Annotation of Amaya/doc/languages.html, revision 1.28
1.21 cvs 1: <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"
2: "http://www.w3.org/TR/REC-html40/loose.dtd">
1.18 cvs 3: <html>
4: <head>
1.21 cvs 5: <title>The Languages of Thot</title>
1.18 cvs 6: </head>
7: <body>
8:
1.19 cvs 9: <div class="frontmatter" align="center">
1.18 cvs 10:
11: <h1>The Languages of Thot</h1>
12:
13: <h3>Vincent Quint</h3>
14:
15: <h4>Translated from French by Ethan Munson</h4>
16:
1.26 cvs 17: <h4>Version of January 14, 2000</h4>
1.18 cvs 18: <p>
19: © 1996 INRIA</p>
20: <hr>
1.19 cvs 21:
1.18 cvs 22: </div>
23:
24: <div class="tableofcontents">
25:
26: <h2><a href="languages.toc.html">Contents</a></h2>
27: <ul>
28: <li>
29: <big><a href="#sect2">The document model of Thot</a></big>
30: <ul>
31: <li>
32: <strong><a href="#sectb21">The logical structure of documents</a></strong>
1.19 cvs 33: </li>
1.18 cvs 34: <li>
35: <strong><a href="#sectb22">Generic and specific structures</a></strong>
1.19 cvs 36: </li>
1.18 cvs 37: <li>
38: <strong><a href="#sectb23">Logical structure and physical
39: structure</a></strong>
1.19 cvs 40: </li>
1.18 cvs 41: <li>
42: <strong><a href="#sectb24">Document structures and object
43: structures</a></strong>
1.19 cvs 44: </li>
1.18 cvs 45: </ul>
1.19 cvs 46: </li>
1.18 cvs 47: <li>
48: <big><a href="#sect3">The S language</a></big>
49: <ul>
50: <li>
51: <strong><a href="#sectb31">Document meta-structure</a></strong>
52: <ul>
53: <li>
54: <a href="#sectc311">The basic types</a>
1.19 cvs 55: </li>
1.18 cvs 56: <li>
57: <a href="#sectc312">Constructed elements</a>
1.19 cvs 58: </li>
1.18 cvs 59: <li>
60: <a href="#sectc313">Logical structure constructors</a>
61: <ul>
62: <li>
63: <small><a href="#sectd3131">Aggregate and List</a></small>
1.19 cvs 64: </li>
1.18 cvs 65: <li>
66: <small><a href="#sectd3132">Choice, Schema, and Unit</a></small>
1.19 cvs 67: </li>
1.18 cvs 68: <li>
69: <small><a href="#sectd3133">Reference and Inclusion</a></small>
1.19 cvs 70: </li>
1.18 cvs 71: <li>
72: <small><a href="#sectd3134">Mark pairs</a></small>
1.19 cvs 73: </li>
1.18 cvs 74: <li>
75: <small><a href="#sectd3135">Restrictions and Extensions</a></small>
1.19 cvs 76: </li>
1.18 cvs 77: <li>
78: <small><a href="#sectd3136">Summary</a></small>
1.19 cvs 79: </li>
1.18 cvs 80: </ul>
1.19 cvs 81: </li>
1.18 cvs 82: <li>
83: <a href="#sectc314">Associated Elements</a>
1.19 cvs 84: </li>
1.18 cvs 85: <li>
86: <a href="#sectc315">Attributes</a>
1.19 cvs 87: </li>
1.18 cvs 88: <li>
89: <a href="#sectc316">Discussion of the model</a>
1.19 cvs 90: </li>
1.18 cvs 91: </ul>
1.19 cvs 92: </li>
1.18 cvs 93: <li>
94: <strong><a href="#sectb32">The definition language for generic
95: structures</a></strong>
96: <ul>
97: <li>
98: <a href="#sectc321">Writing Conventions</a>
1.19 cvs 99: </li>
1.18 cvs 100: <li>
101: <a href="#sectc322">Extension schemas</a>
1.19 cvs 102: </li>
1.18 cvs 103: <li>
104: <a href="#sectc323">The general organization of structure schemas</a>
1.19 cvs 105: </li>
1.18 cvs 106: <li>
107: <a href="#sectc324">The default presentation</a>
1.19 cvs 108: </li>
1.18 cvs 109: <li>
110: <a href="#sectc325">Global Attributes</a>
1.19 cvs 111: </li>
1.18 cvs 112: <li>
113: <a href="#sectc326">Parameters</a>
1.19 cvs 114: </li>
1.18 cvs 115: <li>
116: <a href="#sectc327">Structured elements</a>
1.19 cvs 117: </li>
1.18 cvs 118: <li>
119: <a href="#sectc328">Structure definitions</a>
120: <ul>
121: <li>
122: <small><a href="#sectd3281">List</a></small>
1.19 cvs 123: </li>
1.18 cvs 124: <li>
125: <small><a href="#sectd3282">Aggregate</a></small>
1.19 cvs 126: </li>
1.18 cvs 127: <li>
128: <small><a href="#sectd3283">Choice</a></small>
1.19 cvs 129: </li>
1.18 cvs 130: <li>
131: <small><a href="#sectd3284">Reference</a></small>
1.19 cvs 132: </li>
1.18 cvs 133: <li>
134: <small><a href="#sectd3285">Mark pairs</a></small>
1.19 cvs 135: </li>
1.18 cvs 136: </ul>
1.19 cvs 137: </li>
1.18 cvs 138: <li>
139: <a href="#sectc329">Imports</a>
1.19 cvs 140: </li>
1.18 cvs 141: <li>
142: <a href="#sectc3210">Extension rules</a>
1.19 cvs 143: </li>
1.18 cvs 144: <li>
145: <a href="#sectc3211">Associated elements</a>
1.19 cvs 146: </li>
1.18 cvs 147: <li>
148: <a href="#sectc3212">Units</a>
1.19 cvs 149: </li>
1.18 cvs 150: <li>
151: <a href="#sectc3213">Skeleton elements</a>
1.19 cvs 152: </li>
1.18 cvs 153: <li>
154: <a href="#sectc3214">Exceptions</a>
1.19 cvs 155: </li>
1.18 cvs 156: </ul>
1.19 cvs 157: </li>
1.18 cvs 158: <li>
159: <strong><a href="#sectb33">Some examples</a></strong>
160: <ul>
161: <li>
162: <a href="#sectc331">A class of documents: articles</a>
1.19 cvs 163: </li>
1.18 cvs 164: <li>
165: <a href="#sectc332">A class of objects: mathematical formulas</a>
1.19 cvs 166: </li>
1.18 cvs 167: </ul>
1.19 cvs 168: </li>
1.18 cvs 169: </ul>
1.19 cvs 170: </li>
1.18 cvs 171: <li>
172: <big><a href="#sect4">The P language</a></big>
173: <ul>
174: <li>
175: <strong><a href="#sectb41">Document presentation</a></strong>
176: <ul>
177: <li>
178: <a href="#sectc411">Two levels of presentation</a>
1.19 cvs 179: </li>
1.18 cvs 180: <li>
181: <a href="#sectc412">Boxes</a>
1.19 cvs 182: </li>
1.18 cvs 183: <li>
184: <a href="#sectc413">Views and visibility</a>
1.19 cvs 185: </li>
1.18 cvs 186: <li>
187: <a href="#sectc414">Pages</a>
1.19 cvs 188: </li>
1.18 cvs 189: <li>
190: <a href="#sectc415">Numbering</a>
1.19 cvs 191: </li>
1.18 cvs 192: <li>
193: <a href="#sectc416">Presentation parameters</a>
1.19 cvs 194: </li>
1.18 cvs 195: </ul>
1.19 cvs 196: </li>
1.18 cvs 197: <li>
198: <strong><a href="#sectb42">Presentation description language</a></strong>
199: <ul>
200: <li>
201: <a href="#sectc421">The organization of a presentation schema</a>
1.19 cvs 202: </li>
1.18 cvs 203: <li>
204: <a href="#sectc422">Views</a>
1.19 cvs 205: </li>
1.18 cvs 206: <li>
207: <a href="#sectc423">Print Views</a>
1.19 cvs 208: </li>
1.18 cvs 209: <li>
210: <a href="#sectc424">Counters</a>
1.19 cvs 211: </li>
1.18 cvs 212: <li>
213: <a href="#sectc425">Presentation constants</a>
1.19 cvs 214: </li>
1.18 cvs 215: <li>
216: <a href="#sectc426">Variables</a>
1.19 cvs 217: </li>
1.18 cvs 218: <li>
219: <a href="#sectc427">Default presentation rules</a>
1.19 cvs 220: </li>
1.18 cvs 221: <li>
222: <a href="#sectc428">Presentation and page layout boxes</a>
1.19 cvs 223: </li>
1.18 cvs 224: <li>
225: <a href="#sectc429">Presentation of structured elements</a>
1.19 cvs 226: </li>
1.18 cvs 227: <li>
228: <a href="#sectc4210">Logical attribute presentation</a>
1.19 cvs 229: </li>
1.18 cvs 230: <li>
231: <a href="#sectc4212">Value transmission rules</a>
1.19 cvs 232: </li>
1.18 cvs 233: <li>
234: <a href="#sectc4213">Presentation rules</a>
1.19 cvs 235: </li>
1.18 cvs 236: <li>
237: <a href="#sectc4214">Conditions applying to presentation rules</a>
238: <ul>
239: <li>
240: <small><a href="#sectd42141">Conditions based on the logical position of the
241: element</a></small>
1.19 cvs 242: </li>
1.18 cvs 243: <li>
244: <small><a href="#sectd42142">Conditions on references</a></small>
1.19 cvs 245: </li>
1.18 cvs 246: <li>
247: <small><a href="#sectd42143">Conditions on logical attributes</a></small>
1.19 cvs 248: </li>
1.18 cvs 249: <li>
250: <small><a href="#sectd42144">Conditions on page breaks</a></small>
1.19 cvs 251: </li>
1.18 cvs 252: <li>
253: <small><a href="#sectd42145">Conditions on the element's content</a></small>
1.19 cvs 254: </li>
1.18 cvs 255: <li>
256: <small><a href="#sectd42146">Conditions on counters</a></small>
1.19 cvs 257: </li>
1.18 cvs 258: </ul>
1.19 cvs 259: </li>
1.18 cvs 260: <li>
261: <a href="#sectc4215">A presentation rule</a>
1.19 cvs 262: </li>
1.18 cvs 263: <li>
264: <a href="#sectc4216">Box axes</a>
1.19 cvs 265: </li>
1.18 cvs 266: <li>
267: <a href="#sectc4217">Distance units</a>
1.19 cvs 268: </li>
1.18 cvs 269: <li>
270: <a href="#sectc4218">Relative positions</a>
1.19 cvs 271: </li>
1.18 cvs 272: <li>
273: <a href="#sectc4219">Box extents</a>
274: <ul>
275: <li>
276: <small><a href="#sectd42191">Fixed extents</a></small>
1.19 cvs 277: </li>
1.18 cvs 278: <li>
279: <small><a href="#sectd42192">Relative extents</a></small>
1.19 cvs 280: </li>
1.18 cvs 281: <li>
282: <small><a href="#sectd42193">Elastic extents</a></small>
1.19 cvs 283: </li>
1.18 cvs 284: </ul>
1.19 cvs 285: </li>
1.18 cvs 286: <li>
287: <a href="#sectc4220">Overflow</a>
1.19 cvs 288: </li>
1.18 cvs 289: <li>
290: <a href="#sectc4221">Inheritance</a>
1.19 cvs 291: </li>
1.18 cvs 292: <li>
293: <a href="#sectc4222">Line breaking</a>
294: <ul>
295: <li>
296: <small><a href="#sectd42221">Line spacing</a></small>
1.19 cvs 297: </li>
1.18 cvs 298: <li>
299: <small><a href="#sectd42222">First line indentation</a></small>
1.19 cvs 300: </li>
1.18 cvs 301: <li>
302: <small><a href="#sectd42223">Alignment</a></small>
1.19 cvs 303: </li>
1.18 cvs 304: <li>
305: <small><a href="#sectd42224">Justification</a></small>
1.19 cvs 306: </li>
1.18 cvs 307: <li>
308: <small><a href="#sectd42225">Hyphenation</a></small>
1.19 cvs 309: </li>
1.18 cvs 310: <li>
311: <small><a href="#sectd42226">Avoiding line breaking</a></small>
1.19 cvs 312: </li>
1.18 cvs 313: </ul>
1.19 cvs 314: </li>
1.18 cvs 315: <li>
316: <a href="#sectc4223">Page breaking and line breaking conditions</a>
1.19 cvs 317: </li>
1.18 cvs 318: <li>
319: <a href="#sectc4224">Visibility</a>
1.19 cvs 320: </li>
1.18 cvs 321: <li>
322: <a href="#sectc4225">Character style parameters</a>
323: <ul>
324: <li>
325: <small><a href="#sectd42251">Character size</a></small>
1.19 cvs 326: </li>
1.18 cvs 327: <li>
328: <small><a href="#sectd42252">Font and character style</a></small>
1.19 cvs 329: </li>
1.18 cvs 330: <li>
331: <small><a href="#sectd42253">Underlining</a></small>
1.19 cvs 332: </li>
1.18 cvs 333: </ul>
1.19 cvs 334: </li>
1.18 cvs 335: <li>
336: <a href="#sectc4226">Stacking order</a>
1.19 cvs 337: </li>
1.18 cvs 338: <li>
339: <a href="#sectc4227">Line style</a>
1.19 cvs 340: </li>
1.18 cvs 341: <li>
342: <a href="#sectc4228">Line thickness</a>
1.19 cvs 343: </li>
1.18 cvs 344: <li>
345: <a href="#sectc4229">Fill pattern</a>
1.19 cvs 346: </li>
1.18 cvs 347: <li>
348: <a href="#sectc4230">Colors</a>
1.19 cvs 349: </li>
1.18 cvs 350: <li>
351: <a href="#sectc4230a">Background color and border</a>
1.19 cvs 352: </li>
1.18 cvs 353: <li>
354: <a href="#sectc4230b">Background pictures</a>
1.19 cvs 355: </li>
1.18 cvs 356: <li>
357: <a href="#sectc4231">Presentation box content</a>
1.19 cvs 358: </li>
1.18 cvs 359: <li>
360: <a href="#sectc4232">Presentation box creation</a>
1.19 cvs 361: </li>
1.18 cvs 362: <li>
363: <a href="#sectc4233">Page layout</a>
1.19 cvs 364: </li>
1.18 cvs 365: <li>
366: <a href="#sectc4234">Box copies</a>
1.19 cvs 367: </li>
1.18 cvs 368: </ul>
1.19 cvs 369: </li>
1.18 cvs 370: </ul>
1.19 cvs 371: </li>
1.18 cvs 372: <li>
373: <big><a href="#sect5">The T language</a></big>
374: <ul>
375: <li>
376: <strong><a href="#sectb51">Document translation</a></strong>
377: <ul>
378: <li>
379: <a href="#sectc511">Translation principles</a>
1.19 cvs 380: </li>
1.18 cvs 381: <li>
382: <a href="#sectc512">Translation procedure</a>
1.19 cvs 383: </li>
1.18 cvs 384: </ul>
1.19 cvs 385: </li>
1.18 cvs 386: <li>
387: <strong><a href="#sectb52">Translation definition language</a></strong>
388: <ul>
389: <li>
390: <a href="#sectc521">Organization of a translation schema</a>
1.19 cvs 391: </li>
1.18 cvs 392: <li>
393: <a href="#sectc522">Line length</a>
1.19 cvs 394: </li>
1.18 cvs 395: <li>
396: <a href="#sectc523">Buffers</a>
1.19 cvs 397: </li>
1.18 cvs 398: <li>
399: <a href="#sectc524">Counters</a>
1.19 cvs 400: </li>
1.18 cvs 401: <li>
402: <a href="#sectc525">Constants</a>
1.19 cvs 403: </li>
1.18 cvs 404: <li>
405: <a href="#sectc526">Variables</a>
1.19 cvs 406: </li>
1.18 cvs 407: <li>
408: <a href="#sectc527">Translating structure elements</a>
1.19 cvs 409: </li>
1.18 cvs 410: <li>
411: <a href="#sectc528">Conditional rules</a>
412: <ul>
413: <li>
414: <small><a href="#sectd5281">Conditions based on the logical position of the
415: element</a></small>
1.19 cvs 416: </li>
1.18 cvs 417: <li>
418: <small><a href="#sectd5282">Conditions on references</a></small>
1.19 cvs 419: </li>
1.18 cvs 420: <li>
421: <small><a href="#sectd5283">Conditions on the parameters</a></small>
1.19 cvs 422: </li>
1.18 cvs 423: <li>
424: <small><a href="#sectd5284">Conditions on the alphabets</a></small>
1.19 cvs 425: </li>
1.18 cvs 426: <li>
427: <small><a href="#sectd5285">Conditions on page breaks</a></small>
1.19 cvs 428: </li>
1.18 cvs 429: <li>
430: <small><a href="#sectd5286">Conditions on the element's content</a></small>
1.19 cvs 431: </li>
1.18 cvs 432: <li>
433: <small><a href="#sectd5287">Conditions on the presence of comments</a></small>
1.19 cvs 434: </li>
1.18 cvs 435: <li>
436: <small><a href="#sectd5288">Conditions on the presence of specific
437: presentation rules</a></small>
1.19 cvs 438: </li>
1.18 cvs 439: <li>
440: <small><a href="#sectd5289">Conditions on the presence of logical
441: attributes</a></small>
1.19 cvs 442: </li>
1.18 cvs 443: <li>
444: <small><a href="#sectd52810">Conditions on logical attributes</a></small>
1.19 cvs 445: </li>
1.18 cvs 446: <li>
447: <small><a href="#sectd52811">Conditions on specific presentation
448: rules</a></small>
1.19 cvs 449: </li>
1.18 cvs 450: </ul>
1.19 cvs 451: </li>
1.18 cvs 452: <li>
453: <a href="#sectc529">Translation rules</a>
1.19 cvs 454: </li>
1.18 cvs 455: <li>
456: <a href="#sectc5210">The <tt>Create</tt> rule</a>
1.19 cvs 457: </li>
1.18 cvs 458: <li>
459: <a href="#sectc5211">The <tt>Write</tt> rule</a>
1.19 cvs 460: </li>
1.18 cvs 461: <li>
462: <a href="#sectc5212">The <tt>Read</tt> rule</a>
1.19 cvs 463: </li>
1.18 cvs 464: <li>
465: <a href="#sectc5213">The <tt>Include</tt> rule</a>
1.19 cvs 466: </li>
1.18 cvs 467: <li>
468: <a href="#sectc5214">The <tt>Get</tt> rule</a>
1.19 cvs 469: </li>
1.18 cvs 470: <li>
471: <a href="#sectc5215">The <tt>Copy</tt> rule</a>
1.19 cvs 472: </li>
1.18 cvs 473: <li>
474: <a href="#sectc5216">The <tt>Use</tt> rule</a>
1.19 cvs 475: </li>
1.18 cvs 476: <li>
477: <a href="#sectc5217">The <tt>Remove</tt> rule</a>
1.19 cvs 478: </li>
1.18 cvs 479: <li>
480: <a href="#sectc5218">The <tt>NoTranslation</tt> rule</a>
1.19 cvs 481: </li>
1.18 cvs 482: <li>
483: <a href="#sectc5219">The <tt>NoLineBreak</tt> rule</a>
1.19 cvs 484: </li>
1.18 cvs 485: <li>
486: <a href="#sectc5220">The <tt>ChangeMainFile</tt> rule</a>
1.19 cvs 487: </li>
1.18 cvs 488: <li>
489: <a href="#sectc5220a">The <tt>RemoveFile</tt> rule</a>
1.19 cvs 490: </li>
1.18 cvs 491: <li>
492: <a href="#sectc5221">The <tt>Set</tt> and <tt>Add</tt> rules</a>
1.19 cvs 493: </li>
1.18 cvs 494: <li>
495: <a href="#sectc5221a">The <tt>Indent</tt> rule</a>
1.19 cvs 496: </li>
1.18 cvs 497: <li>
498: <a href="#sectc5222">Rule application order</a>
1.19 cvs 499: </li>
1.18 cvs 500: <li>
501: <a href="#sectc5223">Translation of logical attributes</a>
1.19 cvs 502: </li>
1.18 cvs 503: <li>
504: <a href="#sectc5224">Translation of specific presentations</a>
1.19 cvs 505: </li>
1.18 cvs 506: <li>
507: <a href="#sectc5225">Recoding of characters, symbols and graphics</a>
1.19 cvs 508: </li>
1.18 cvs 509: </ul>
1.19 cvs 510: </li>
1.18 cvs 511: </ul>
1.19 cvs 512: </li>
1.18 cvs 513: <li>
514: <big><a href="#sect6">Language grammars</a></big>
515: <ul>
516: <li>
517: <strong><a href="#sectb61">The M meta-language</a></strong>
1.19 cvs 518: </li>
1.18 cvs 519: <li>
520: <strong><a href="#sectb62">The S language</a></strong>
1.19 cvs 521: </li>
1.18 cvs 522: <li>
523: <strong><a href="#sectb63">The P language</a></strong>
1.19 cvs 524: </li>
1.18 cvs 525: <li>
526: <strong><a href="#sectb64">The T language</a></strong>
1.19 cvs 527: </li>
1.18 cvs 528: </ul>
1.19 cvs 529: </li>
1.18 cvs 530: <li>
531: <big><a href="#sect7">Character coding</a></big>
532: <ul>
533: <li>
534: <strong><a href="#sectb71">Characters</a></strong>
1.19 cvs 535: </li>
1.18 cvs 536: <li>
537: <strong><a href="#sectb72">Symbols</a></strong>
1.19 cvs 538: </li>
1.18 cvs 539: <li>
540: <strong><a href="#sectb73">Graphical elements</a></strong>
1.19 cvs 541: </li>
1.18 cvs 542: </ul>
1.19 cvs 543: </li>
1.18 cvs 544: </ul>
545: <hr>
1.19 cvs 546:
1.18 cvs 547: </div>
1.1 cvs 548:
1.18 cvs 549: <div class="chapter">
1.1 cvs 550:
1.18 cvs 551: <h1><a name="sect2">The document model of Thot</a></h1>
552: <p>
1.1 cvs 553: All of the services which Thot provides to the user are based on the system's
554: internal document representation. This representation is itself derived from
555: the document model which underlies Thot. The model is presented here, prior
556: to the description of the languages which permit the generic specification of
1.18 cvs 557: documents.</p>
1.1 cvs 558:
1.18 cvs 559: <div class="section">
1.1 cvs 560:
1.18 cvs 561: <h2><a name="sectb21">The logical structure of documents</a></h2>
562: <p>
1.1 cvs 563: The document model of Thot is primarily designed to allow the user to operate
1.5 cvs 564: on those entities which s/he has in mind when s/he works on a document. The
565: model makes no assumptions about the nature of these entities. It is
566: essentially these logical entities, such as paragraphs, sections, chapters,
567: notes, titles, and cross-references which give a document its logical
1.18 cvs 568: structure.</p>
569: <p>
1.5 cvs 570: Because of this model, the author can divide the document into chapters,
1.1 cvs 571: giving each one a title. The content of these chapters can be further divided
1.2 cvs 572: into sections, subsections, etc. The text is organized into successive
573: paragraphs, according to the content. In the writing phase, the lines, pages,
574: margins, spacing, fonts, and character styles are not very important. In fact,
575: if the system requires documents to be written in these terms, it gets in the
576: way. So, Thot's model is primarily based on the logical aspect of documents.
1.18 cvs 577: The creation of a model of this type essentially requires the definition :</p>
578: <ul>
579: <li>
580: of the entities which can appear in the documents,
1.19 cvs 581: </li>
1.18 cvs 582: <li>
583: and the relations between these entities.
1.19 cvs 584: </li>
1.18 cvs 585: </ul>
586: <p>
1.1 cvs 587: The choice of entities to include in the model can be subtle. Some documents
588: require chapters, while others only need various levels of sections. Certain
589: documents contain appendices, others don't. In different documents the same
590: logical entity may go by different names (e.g. ``Conclusion'' and
591: ``Summary''). Certain entities which are absolutely necessary in some
592: documents, such as clauses in a contract or the address of the recipient in a
1.18 cvs 593: letter, are useless in most other cases.</p>
594: <p>
1.1 cvs 595: The differences between documents result from more than just the entities that
596: appear in them, but also from the relationships between these entities and the
597: ways that they are linked. In certain documents, notes are spread throughout
598: the document, for example at the bottom of the page containing the
599: cross-reference to them, while in other documents they are collected at the
600: end of each chapter or even at the end of the work. As another example, the
601: introduction of some documents can contain many sections, while in other
602: documents, the introduction is restricted to be a short sequence of
1.18 cvs 603: paragraphs.</p>
604: <p>
1.1 cvs 605: All of this makes it unlikely that a single model can describe any document at
606: a relatively high level. It is obviously tempting to make up a list of widely
607: used entities, such as chapters, sections, paragraphs, and titles, and then
608: map all other entities onto the available choices. In this way, an
609: introduction can be supported as a chapter and a contract clause supported as
610: a paragraph or section. However, in trying to widen the range of usage of
611: certain entities, their meaning can be lost and the power of the model
612: reduced. In addition, while this widening partially solves the problem of
613: choosing entities, it does not solve the problem of their organization: when a
614: chapter must be composed of sections, how does one indicate that an
615: introduction has none when it is merely another chapter? One solution is to
616: include introductions in the list of supported entities. But then, how does
617: one distinguish those introductions which are allowed to have sections from
618: those which are not. Perhaps this could be done by defining two types of
619: introduction. Clearly, this approach risks an infinite expansion of the list
1.18 cvs 620: of widely used entities.</p>
621: </div>
1.1 cvs 622:
1.18 cvs 623: <div class="section">
1.1 cvs 624:
1.18 cvs 625: <h2><a name="sectb22">Generic and specific structures</a></h2>
626: <p>
1.1 cvs 627: Thus, it is apparently impossible to construct an exhaustive inventory of all
1.2 cvs 628: those entities which are necessary and sufficient to precisely describe any
629: document. It also seems impossible to specify all possible arrangements of
1.18 cvs 630: these entities in a document. This is why Thot uses a <em>meta-model</em>
631: instead, which permits the description of numerous <em>models</em>, each one
632: describing a <em>class</em> of documents.</p>
633: <p>
634: A <em>class</em> is a set of documents having very similar structure. Thus,
1.1 cvs 635: the collection of research reports published by a laboratory constitutes a
636: class; the set of commercial proposals by the sales department of a company
637: constitutes another class; the set of articles published by a journal
638: constitutes a third class. Clearly, it is not possible to enumerate every
639: possible document class. It is also clear that new document classes must be
1.18 cvs 640: created to satisfy new needs and applications.</p>
641: <p>
1.1 cvs 642: To give a more rigorous definition of classes, we must introduce the ideas of
1.18 cvs 643: <em>generic structure</em> and <em>specific structure</em>. Each document has
644: a <em>specific structure</em> which organizes the various parts which comprise
1.1 cvs 645: it. We illustrate this with the help of a simple example comparing two
1.18 cvs 646: reports, A and B (<a href="#specstruct">see Figure</a>). The report A contains
1.1 cvs 647: an introduction followed by three chapters and a conclusion. The first
648: chapter contains two sections, the second, three sections. That is the
1.18 cvs 649: <em>specific</em> structure of document A. Similarly, the structure of
1.1 cvs 650: document B is: an introduction, two chapters, a conclusion; Chapter 1 has
651: three sections while Chapter 2 has four. The specific structures of these two
1.18 cvs 652: documents are thus different.</p>
1.1 cvs 653:
1.18 cvs 654: <div class="figure">
655: <hr>
1.19 cvs 656:
1.18 cvs 657: <pre> Report A Report B
1.1 cvs 658: Introduction Introduction
659: Chapter 1 Chapter 1
660: Section 1.1 Section 1.1
661: Section 1.2 Section 1.2
662: Chapter 2 Section 1.3
663: Section 2.1 Chapter 2
664: Section 2.2 Section 2.1
665: Section 2.3 Section 2.2
666: Chapter 3 Section 2.3
667: Conclusion Section 2.4
1.18 cvs 668: Conclusion</pre>
1.19 cvs 669: <p align="center">
1.18 cvs 670: <em><a name="specstruct">Two specific structures</a></em></p>
671: <hr>
1.19 cvs 672:
1.18 cvs 673: </div>
674: <p>
675: The <em>generic structure</em> defines the ways in which specific structures
1.1 cvs 676: can be constructed. It specifies how to generate specific structures. The
677: reports A and B, though different, are constructed in accordance with the same
678: generic structure, which specifies that a report contains an introduction
679: followed by a variable number of chapters and a conclusion, with each chapter
1.18 cvs 680: containing a variable number of sections.</p>
681: <p>
1.1 cvs 682: There is a one-to-one correspondence between a class and a generic structure:
683: all the documents of a class are constructed in accordance with the same
684: generic structure. Hence the definition of the class: a class is a set of
685: documents whose specific structure is constructed in accordance with the same
1.18 cvs 686: generic structure. A class is characterized by its generic structure.</p>
687: <p>
1.1 cvs 688: Thus, a generic structure can be considered to be a model at the level which
689: interests us, but only for one class of documents. When the definition is
690: limited to a single class of documents, it is possible to define a model which
691: does a good job of representing the documents of the class, including the
692: necessary entities and unencumbered by useless entities. The description of
693: the organization of the documents in the class can then be sufficiently
1.18 cvs 694: precise.</p>
695: </div>
1.1 cvs 696:
1.18 cvs 697: <div class="section">
1.1 cvs 698:
1.18 cvs 699: <h2><a name="sectb23">Logical structure and physical structure</a></h2>
700: <p>
701: Generic structures only describe the <em>logical</em> organization of
702: documents, not their <em>physical</em> presentation on a screen or on sheets
1.1 cvs 703: of paper. However, for a document to be displayed or printed, its graphic
1.18 cvs 704: presentation must be taken into account.</p>
705: <p>
1.1 cvs 706: An examination of current printed documents shows that the details of
707: presentation essentially serve to bring out their logical structure. Outside
708: of some particular domains, notably advertising, the presentation is rarely
709: independent of the logical organization of the text. Moreover, the art of
710: typography consists of enhancing the organization of the text being set,
711: without catching the eye of the reader with overly pronounced effects. Thus,
712: italic and boldface type are used to emphasize words or expressions which have
713: greater significance than the rest of the text: keywords, new ideas,
714: citations, book titles, etc. Other effects highlight the organization of the
715: text: vertical space, margin changes, page breaks, centering, eventually
716: combined with the changes in the shapes or weight of the characters. These
717: effects serve to indicate the transitions between paragraphs, sections, or
718: chapters: an object's level in the logical structure of the document is shown
1.18 cvs 719: by the markedness of the effects.</p>
720: <p>
1.1 cvs 721: Since the model permits the description of all of the logical structure of the
722: document, the presentation can be derived from the model without being
723: submerged in the document itself. It suffices to use the logical structure of
724: the document to make the desired changes in its presentation: changes in type
1.18 cvs 725: size, type style, spacing, margin, centering, etc.</p>
726: <p>
1.1 cvs 727: Just as one cannot define a unique generic logical structure for all document
728: classes, one cannot define universal presentation rules which can be applied
729: to all document classes. For certain types of documents the chapter titles
730: will be centered on the page and printed in large, bold type. For other
731: documents, the same chapter titles will be printed in small, italic type and
1.18 cvs 732: aligned on the left margin.</p>
733: <p>
1.1 cvs 734: Therefore, it is necessary to base the presentation specifications for
735: documents on their class. Such a specification can be very fine-grained,
736: because the presentation is expressed in terms of the entities defined in the
737: generic logical structure of the class. Thus, it is possible to specify a
738: different presentation for the chapter titles and the section titles, and
739: similarly to specify titles for the sections according to their level in the
740: section hierarchy. The set of rules which specify the presentation of all the
1.18 cvs 741: elements defined in a generic logical structure is called a <em>generic
742: presentation</em>.</p>
743: <p>
1.1 cvs 744: There are several advantages derived from having a presentation linked to the
745: generic structure and described by a generic presentation. Homogeneity is the
746: first. Since every document in a class corresponds to the same generic
747: logical structure, a homogenous presentation for different documents of the
748: same class can be assured by applying the same generic presentation to all
749: documents of the class. Homogeneity of presentation can also be found among
1.2 cvs 750: the entities of a single document: every section heading will be presented in
1.1 cvs 751: the same way, the first line of every paragraph of the same type will have the
1.18 cvs 752: same indentation, etc.</p>
753: <p>
1.1 cvs 754: Another advantage of this approach to presentation is that it facilitates
755: changes to the graphical aspect of documents. A change to the generic
756: presentation rules attached to each type of entity will alter the presentation
757: of the entire document, and will do so homogenously. In this case, the
758: internal homogeneity of the class is no longer assured, but the way to control
759: it is simple. It suffices to adopt a single generic presentation for the
1.18 cvs 760: entire class.</p>
761: <p>
1.1 cvs 762: If the presentation of the class does not have to be homogenous, then the
763: appearance of the document can be adapted to the way it will be used or to the
764: device used to render it. This quality is sufficient to allow the existence
1.18 cvs 765: of <a name="mulpres">many generic presentations</a> for the same document
1.1 cvs 766: class. By applying one or the other of these presentations to it, the document
767: can be seen under different graphical aspects. It must be emphasized that
768: this type of modification of the presentation is not a change to the document
769: itself (in its specific logical structure or its content), but only in its
1.18 cvs 770: appearance at the time of editing or printing.</p>
771: </div>
1.1 cvs 772:
1.18 cvs 773: <div class="section">
1.1 cvs 774:
1.18 cvs 775: <h2><a name="sectb24">Document structures and object structures</a></h2>
776: <p>
1.1 cvs 777: So far, we have only discussed the global structure of documents and have not
778: considered the contents found in that structure. We could limit ourselves to
779: purely textual contents by assuming that a title or a paragraph contains a
780: simple linear text. But this model would be too restrictive. In fact,
781: certain documents contain not only text, but also contain tables, diagrams,
782: photographs, mathematical formulas, and program fragments. The model must
1.18 cvs 783: permit the representation of such <em>objects</em>.</p>
784: <p>
1.1 cvs 785: Just as with the whole of the document, the model takes into account the
786: logical structure of objects of this type. Some are clearly structured,
787: others are less so. Logical structure can be recognized in mathematical
788: formulas, in tables, and in certain types of diagrams. On the other hand, it
789: is difficult to define the structure of a photograph or of some drawings. But
790: in any case, it does not seem possible to define one unique structure which
791: can represent every one of these types of objects. The approach taken in the
792: definition of meta-structure and document classes also applies to objects.
793: Object classes can be defined which put together objects of similar type,
1.18 cvs 794: constructed from the same generic logical structure.</p>
795: <p>
1.1 cvs 796: Thus, a mathematical class can be defined and have a generic logical structure
797: associated with it. But even if a single generic structure can represent a
798: sufficient variety of mathematical formulas, for other objects with less
799: rigorous structure, multiple classes must be defined. As for documents, using
800: multiple classes assures that the model can describe the full range of objects
801: to be presented. It also permits the system to support objects which were not
802: initially anticipated. Moreover, this comment applies equally to mathematics:
803: different classes of formulas can be described depending on the domain of
1.18 cvs 804: mathematics being described.</p>
805: <p>
1.1 cvs 806: Since objects have the same level of logical representation as documents, they
807: gain the same advantages. In particular, it is possible to define the
808: presentation separately from the objects themselves and attach it to the
809: class. Thus, as for documents, objects of the same type have a uniform
810: presentation and the presentation of every object in a given class can be
811: changed simply by changing the generic presentation of the class. Another
812: advantage of using this document model is that the system does not bother the
813: user with the details of presentation, but rather allows the user to
1.18 cvs 814: concentrate on the logical aspect of the document and the objects.</p>
815: <p>
1.1 cvs 816: It is clear that the documents in a class do not necessarily use the same
817: classes of objects: one technical report will contain tables while another
818: report will have no tables but will use mathematical formulas. The usable
1.2 cvs 819: object classes are not always mentioned in a limiting way in the generic
820: logical structure of documents. Rather, they can be chosen freely from a
1.18 cvs 821: large set, independent of the document class.</p>
822: <p>
1.1 cvs 823: Thus, the object classes will be made commonplace and usable in every
824: document. The notion of ``object'' can be enlarged to include not only
825: non-textual elements, but also certain types of textual elements which can
826: appear in practically every document, whatever their class. Among these
1.2 cvs 827: textual elements, one can mention enumerations, descriptions, examples,
1.18 cvs 828: quotations, even paragraphs.</p>
829: <p>
1.1 cvs 830: Thus, the document model is not a single, general model describing every type
831: of document in one place. Rather, it is a meta-model which can be used to
832: describe many different models each of which represents either a class of
833: similar documents or a class of similar objects which every document can
1.18 cvs 834: include.</p>
835: </div>
836: <hr>
1.19 cvs 837:
1.18 cvs 838: </div>
1.1 cvs 839:
1.18 cvs 840: <div class="chapter">
1.1 cvs 841:
1.18 cvs 842: <h1><a name="sect3">The S language</a></h1>
1.1 cvs 843:
1.18 cvs 844: <div class="section">
1.1 cvs 845:
1.18 cvs 846: <h2><a name="sectb31">Document meta-structure</a></h2>
847: <p>
1.1 cvs 848: Since the concept of meta-structure is well suited to the task of describing
849: documents at a high level of abstraction, this meta-structure must be
850: precisely defined. Toward that end this section first presents the basic
851: elements from which documents and structured objects are composed and then
852: specifies the ways in which these basic elements are assembled into structures
1.18 cvs 853: representing complete documents and objects.</p>
1.1 cvs 854:
1.18 cvs 855: <div class="subsection">
1.1 cvs 856:
1.18 cvs 857: <h3><a name="sectc311">The basic types</a></h3>
858: <p>
1.1 cvs 859: At the lowest level of a document's structure, the first atom considered is
860: the character. However, since characters are seldom isolated, usually
861: appearing as part of a linear sequence, and in order to reduce the complexity
1.18 cvs 862: of the document structure, <em>character strings</em> are used as atoms and
1.1 cvs 863: consecutive characters belonging to the same structural element are grouped in
1.18 cvs 864: the same character string.</p>
865: <p>
1.1 cvs 866: If the structure of a document is not refined to go down to the level of
867: words or phrases, the contents of a simple paragraph can be considered to be a
868: single character string. On the other hand, the title of a chapter, the title
869: of the first section of that chapter, and the text of the first paragraph of
870: that section constitute three different character strings, because they belong
1.18 cvs 871: to distinct structural elements.</p>
872: <p>
1.1 cvs 873: If, instead, a very fine-grained representation for the structure of a
874: document is sought, character strings could be defined to contain only a
875: single word, or even just a single character. This is the case, for example,
876: in programs, for which one wants to retain a structure very close to the
1.2 cvs 877: syntax of the programming language. In this case, an assignment statement
1.1 cvs 878: initializing a simple variable to zero would be composed of two structural
879: elements, the identifier of the variable (a short character string) and the
1.18 cvs 880: assigned value (a string of a single character, `0').</p>
881: <p>
1.1 cvs 882: The character string is not the only atom necessary for representing those
883: documents that interest us. It suffices for purely textual documents, but as
884: soon as the non-textual objects which we have considered arise, there must be
885: other atoms; the number of objects which are to be represented determines the
1.18 cvs 886: number of types of atoms that are necessary.</p>
887: <p>
888: Primitive <em>graphical elements</em> are used for tables and figures of
1.1 cvs 889: different types. These elements are simple geometric shapes like horizontal
890: or vertical lines, which are sufficient for tables, or even oblique lines,
1.2 cvs 891: arrows, rectangles, circles, polygons, and curves for use in figures. From
892: these elements and character strings, graphical objects and tables can be
1.18 cvs 893: constructed.</p>
894: <p>
1.1 cvs 895: Photographs, though having very little structure, must still appear in
1.18 cvs 896: documents. They are supported by <em>picture</em> elements, which are
897: represented as matrices of pixels.</p>
898: <p>
1.1 cvs 899: Finally, mathematical notations require certain elements which are
1.18 cvs 900: simultaneously characters and graphical elements, the <em>symbols</em>. By way
1.2 cvs 901: of example, radicals, integration signs, or even large parentheses are
1.1 cvs 902: examples of this type of atom. The size of each of these symbols is
903: determined by its environment, that is to say, by the expression to which it
1.18 cvs 904: is attached.</p>
905: <p>
1.1 cvs 906: To summarize, the primitive elements which are used in the construction of
1.18 cvs 907: documents and structured objects are:</p>
908: <ul>
909: <li>
910: character strings,
1.19 cvs 911: </li>
1.18 cvs 912: <li>
913: graphical elements,
1.19 cvs 914: </li>
1.18 cvs 915: <li>
916: pictures,
1.19 cvs 917: </li>
1.18 cvs 918: <li>
919: and mathematical symbols.
1.19 cvs 920: </li>
1.18 cvs 921: </ul>
922: </div>
1.1 cvs 923:
1.18 cvs 924: <div class="subsection">
1.1 cvs 925:
1.18 cvs 926: <h3><a name="sectc312">Constructed elements</a></h3>
927: <p>
1.1 cvs 928: A document is evidently formed from primitive elements. But the model of Thot
929: also proposes higher level elements. Thus, in a document composed of several
930: chapters, each chapter is an element, and in the chapters each section is also
1.18 cvs 931: an element, and so on. A document is thus an organized set of elements.</p>
932: <p>
1.1 cvs 933: In a document there are different sorts of elements. Each element has a
1.18 cvs 934: <em>type</em> which indicates the role of the element within the document as a
1.1 cvs 935: whole. Thus, we have, for example, the chapter and section types. The
936: document is made up of typed elements: elements of the type chapter and
937: elements of the type section, among others, but also character string elements
938: and graphical elements: the primitive elements are typed elements just as
939: well. At the other extreme, the document itself is also considered to be a
1.18 cvs 940: typed element.</p>
941: <p>
1.1 cvs 942: The important difference between the primitive elements and the other elements
943: of the document is that the primitive elements are atoms (they cannot be
1.18 cvs 944: decomposed), whereas the others, called <em>constructed elements</em>, are
1.1 cvs 945: composed of other elements, which can either be primitive elements or
946: constructed elements. A constructed element of type chapter (or more simply,
947: ``a chapter'') is composed of sections, which are also constructed elements. A
948: paragraph, a constructed element, can be made up of character strings, which
1.18 cvs 949: are primitive elements, and of equations, which are constructed elements.</p>
950: <p>
1.1 cvs 951: A document is also a constructed element. This is an important point. In
952: particular, it allows a document to be treated as part of another document,
953: and conversely, permits a part of a document to be treated as a complete
954: document. Thus, an article presented in a journal is treated by its author as
955: a document in itself, while the editor of the journal considers it to be part
956: of an issue. A table or a figure appearing in a document can be extracted and
957: treated as a complete document, for example to prepare transparencies for a
1.18 cvs 958: conference.</p>
959: <p>
1.1 cvs 960: These thoughts about types and constructed elements apply just as well to
961: objects as they do to documents. A table is a constructed element made up of
962: other constructed elements, rows and columns. A row is formed of cells, which
963: are also constructed elements which contain primitive elements (character
1.18 cvs 964: strings) and/or constructed elements like equations.</p>
965: </div>
1.1 cvs 966:
1.18 cvs 967: <div class="subsection">
1.1 cvs 968:
1.18 cvs 969: <h3><a name="sectc313">Logical structure constructors</a></h3>
970: <p>
1.1 cvs 971: Having defined the primitive elements and the constructed elements, it is now
972: time to define the types of organization which allow the building of
1.18 cvs 973: structures. For this, we rely on the notion of the <em>constructor</em>. A
1.1 cvs 974: constructor defines a way of assembling certain elements in a structure. It
975: resides at the level of the meta-structure: it does not describe the existing
976: relations in a given structure, but rather defines how elements are assembled
1.18 cvs 977: to build a structure that conforms to a model.</p>
978: <p>
1.1 cvs 979: In defining the overall organization of documents, the first two constructors
1.18 cvs 980: considered are the aggregate and the list.</p>
1.1 cvs 981:
1.18 cvs 982: <div class="subsubsection">
1.1 cvs 983:
1.18 cvs 984: <h4><a name="sectd3131">Aggregate and List</a></h4>
985: <p>
986: The <em>aggregate</em> constructor is used to define constructed element types
1.1 cvs 987: which are collections of a given number of other elements. These collections
988: may or may not be ordered. The elements may be either constructed or
989: primitive and are specified by their type. A report (that is, a constructed
990: element of the report type) has an aggregate structure. It is formed from a
991: title, an author's name, an introduction, a body, and a conclusion, making it
992: a collection of five element types. This type of constructor is found in
1.18 cvs 993: practically every document, and generally at several levels in a document.</p>
994: <p>
995: The <em>list</em> constructor is used to define constructed elements which are
1.1 cvs 996: ordered sequences of elements (constructed or primitive) having the same type.
997: The minimum and maximum numbers of elements for the sequence can be specified
998: in the list constructor or the number of elements can be left unconstrained.
999: The body of a report is a list of chapters and is typically required to
1000: contain a minimum of two chapters (is a chapter useful if it is the only one
1001: in the report?) The chapter itself can contain a list of sections, each
1.2 cvs 1002: section containing a list of paragraphs. In the same way as the aggregate,
1.18 cvs 1003: the list is a very frequently used constructor in every type of document.
1.2 cvs 1004: However, these two constructors are not sufficient to describe every document
1.18 cvs 1005: structure; thus other constructors supplement them.</p>
1006: </div>
1.1 cvs 1007:
1.18 cvs 1008: <div class="subsubsection">
1.1 cvs 1009:
1.18 cvs 1010: <h4><a name="sectd3132">Choice, Schema, and Unit</a></h4>
1011: <p>
1012: The <em>choice</em> constructor is used to define the structure of an element
1.1 cvs 1013: type for which one alternative is chosen from several possibilities. Thus, a
1014: paragraph can be either a simple text paragraph, or an enumeration, or a
1.18 cvs 1015: citation.</p>
1016: <p>
1.1 cvs 1017: The choice constructor indicates the complete list of possible options, which
1018: can be too restrictive in certain cases, the paragraph being one such case.
1.18 cvs 1019: Two constructors, <em>unit</em> and <em>schema</em>, address this
1.1 cvs 1020: inconvenience. They allow more freedom in the choice of an element type. If
1021: a paragraph is defined by a schema constructor, it is possible to put in the
1022: place of a paragraph a table, an equation, a drawing or any other object
1023: defined by another generic logical structure. It is also possible to define a
1024: paragraph as a sequence of units, which could be character strings, symbols,
1.2 cvs 1025: or pictures. The choice constructor alone defines a generic logical structure
1.1 cvs 1026: that is relatively constrained; in contrast, using units and schemas, a very
1.18 cvs 1027: open structure can be defined.</p>
1028: <p>
1029: The <em>schema</em> constructor represents an object defined by a generic
1030: logical structure chosen freely from among those available.</p>
1031: <p>
1032: The <em>unit</em> constructor represents an element whose type can be either a
1.1 cvs 1033: primitive type or an element type defined as a unit in the generic logical
1034: structure of the document, or in another generic logical structure used in the
1035: document. Such an element may be used in document objects constructed
1.18 cvs 1036: according to other generic structures.</p>
1037: <p>
1.1 cvs 1038: Thus, for example, if a cross-reference to a footnote is defined in the
1039: generic logical structure ``Article'' as a unit, a table (an object defined by
1040: another generic structure) can contain cross-references to footnotes, when
1041: they appear in an article. In another type of document, a table defined by
1042: the same generic structure can contain other types of elements, depending on
1043: the type of document into which the table is inserted. All that is needed is
1044: to declare, in the generic structure for tables, that the contents of cells
1045: are units. In this way, the generic structure of objects is divided up
1046: between different types of documents which are able to adapt themselves to the
1.18 cvs 1047: environment into which they are inserted.</p>
1048: </div>
1.1 cvs 1049:
1.18 cvs 1050: <div class="subsubsection">
1.1 cvs 1051:
1.18 cvs 1052: <h4><a name="sectd3133">Reference and Inclusion</a></h4>
1053: <p>
1054: The <em>reference</em> is used to define document elements that are
1055: cross-references to other elements, such as a section, a chapter, a
1056: bibliographic citation, or a figure. The reference is bi-directional. It can
1057: be used to access both the element being cross-referenced and each of the
1058: elements which make use of the cross-reference.</p>
1059: <p>
1060: References can be either <em>internal</em> or <em>external</em>. That is,
1.1 cvs 1061: they can designate elements which appear in the same document or in another
1.18 cvs 1062: document.</p>
1063: <p>
1064: The <em><a name="inclusion">inclusion</a></em> constructor is a special type
1.1 cvs 1065: of reference. Like the reference, it is an internal or external bidirectional
1066: link, but it is not a cross-reference. This link represents the ``live''
1067: inclusion of the designated element; it accesses the most recent version of
1068: that element and not a ``dead'' copy, fixed in the state in which it was found
1069: at the moment the copy was made. As soon as an element is modified, all of
1070: its inclusions are automatically brought up to date. It must be noted that,
1.18 cvs 1071: in addition to inclusion, Thot permits the creation of ``dead'' copies.</p>
1072: <p>
1.1 cvs 1073: There are three types of inclusions: inclusions with full expansion,
1074: inclusions with partial expansion, and inclusions without expansion. During
1075: editing, inclusions without expansion are represented on the screen by the
1076: name of the included document, in a special color, while inclusions with
1077: expansion (full or partial) are represented by a copy (full or partial) of the
1078: included element (also in a special color). The on-screen representation of a
1.18 cvs 1079: partial inclusion is a <a href="#sectc3213">``skeleton''</a> image of the
1080: included document.</p>
1081: <p>
1.1 cvs 1082: Inclusion with complete expansion can be used to include parts of the same
1083: document or of other documents. Thus, it can be either an internal or an
1084: external link. It can be used to include certain bibliographic entries of a
1085: scientific article in another article, or to copy part of a mathematical
1086: formula into another formula of the same document, thus assuring that both
1.18 cvs 1087: copies will remain synchronized.</p>
1088: <p>
1.1 cvs 1089: Inclusion without expansion or with partial expansion is used to include
1090: complete documents. It is always an external link. It is used primarily to
1091: divide very large documents into sub-documents that are easier to manipulate,
1092: especially when there are many authors. So, a book can include some chapters,
1093: where each chapter is a different document which can be edited separately.
1094: When viewing the book on the screen, it might be desirable to see only the
1095: titles of the chapters and sections. This can be achieved using inclusion
1.18 cvs 1096: with partial expansion.</p>
1097: <p>
1.1 cvs 1098: During printing, inclusions without expansion or with partial expansion can be
1099: represented either as they were shown on the screen or by a complete (and
1.18 cvs 1100: up-to-date) copy of the included element or document.</p>
1101: <p>
1.1 cvs 1102: The inclusion constructor, whatever its type, respects the generic structure:
1103: only those elements authorized by the generic structure can be included at a
1.18 cvs 1104: given position in a document.</p>
1105: </div>
1.1 cvs 1106:
1.18 cvs 1107: <div class="subsubsection">
1.1 cvs 1108:
1.18 cvs 1109: <h4><a name="sectd3134">Mark pairs</a></h4>
1110: <p>
1.1 cvs 1111: It is often useful to delimit certain parts of a document independently from
1112: the logical structure. For example, one might wish to attach some information
1.18 cvs 1113: (in the form of an <a href="#sectc315">attribute</a>) or a particular
1114: treatment to a group of words or a set of consecutive paragraphs. <em>Mark
1115: pairs</em> are used to do this.</p>
1116: <p>
1.1 cvs 1117: Mark pairs are elements which are always paired and are terminals in the
1118: logical structure of the document. Their position in the structure of the
1119: document is defined in the generic structure. It is important to note that
1.18 cvs 1120: when the terminals of a mark pair are <em>extensions</em> (see the next
1121: section), they can be used quite freely.</p>
1122: </div>
1.1 cvs 1123:
1.18 cvs 1124: <div class="subsubsection">
1.1 cvs 1125:
1.18 cvs 1126: <h4><a name="sectd3135">Restrictions and Extensions</a></h4>
1127: <p>
1.1 cvs 1128: The primitive types and the constructors presented so far permit the
1129: definition of the logical structure of documents and objects in a rigorous
1130: way. But this definition can be very cumbersome in certain cases, notably
1131: when trying to constrain or extend the authorized element types in a
1.18 cvs 1132: particular context. <em>Restrictions</em> and <em>extensions</em> are used to
1133: cope with these cases.</p>
1134: <p>
1135: A restriction associates with a particular element type <em>A</em>, a list of
1136: those element types which elements of type <em>A</em> may not contain, even if
1137: the definition of type <em>A</em> and those of its components authorize them
1.1 cvs 1138: otherwise. This simplifies the writing of generic logical structures and
1139: allows limitations to be placed, when necessary, on the choices offered by the
1.18 cvs 1140: schema and unit constructors.</p>
1141: <p>
1.1 cvs 1142: Extensions are the inverse of restrictions. They identify a list of element
1.18 cvs 1143: types whose presence <em>is</em> permitted, even if its definition and those
1144: of its components do not authorize them otherwise.</p>
1145: </div>
1146:
1147: <div class="subsubsection">
1148:
1149: <h4><a name="sectd3136">Summary</a></h4>
1150: <p>
1151: Thus, four constructors are used to construct a document:</p>
1152: <ul>
1153: <li>
1154: the aggregate constructor (ordered or not),
1.19 cvs 1155: </li>
1.18 cvs 1156: <li>
1157: the list constructor,
1.19 cvs 1158: </li>
1.18 cvs 1159: <li>
1160: the choice constructor and its extensions, the unit and schema constructors,
1.19 cvs 1161: </li>
1.18 cvs 1162: <li>
1163: the reference constructor and its variant, the inclusion.
1.19 cvs 1164: </li>
1.18 cvs 1165: </ul>
1166: <p>
1.1 cvs 1167: These constructors are also sufficient for objects. Thus, these constructors
1168: provide a homogenous meta-model which can describe both the organization of
1169: the document as a whole and that of the various types of objects which it
1170: contains. After presenting the description language for generic structures,
1171: we will present several examples which illustrate the appropriateness of the
1.18 cvs 1172: model.</p>
1173: <p>
1.1 cvs 1174: The first three constructors (aggregate, list and choice) lead to tree-like
1175: structures for documents and objects, the objects being simply the subtrees of
1176: the tree of a document (or even of other objects' subtrees). The reference
1177: constructor introduces other, non-hierarchical, relations which augment those
1178: of the tree: when a paragraph makes reference to a chapter or a section, that
1179: relation leaves the purely tree-like structure. Moreover, external reference
1180: and inclusion constructors permit the establishment of links between different
1.18 cvs 1181: documents, thus creating a hypertext structure.</p>
1182: </div>
1183: </div>
1.1 cvs 1184:
1.18 cvs 1185: <div class="subsection">
1.1 cvs 1186:
1.18 cvs 1187: <h3><a name="sectc314">Associated Elements</a></h3>
1188: <p>
1.1 cvs 1189: Thanks to the list, aggregate and choice constructors, the organization of the
1190: document is specified rigorously, using constructed and primitive elements.
1191: But a document is made up of more than just its elements; it clearly also
1192: contains links between them. There exist elements whose position in the
1193: document's structure is not determinable. This is notably the case for
1194: figures and notes. A figure can be designated at many points in the same
1195: document and its place in the physical document can vary over the life of the
1196: document without any effect on the meaning or clarity of the document. At one
1197: time, it can be placed at the end of the document along with all other
1198: figures. At another time, it can appear at the top of the page which follows
1199: the first mention of the figure. The figures can be dispersed throughout the
1200: document or can be grouped together. The situation is similar for notes,
1201: which can be printed at the bottom of the page on which they are mentioned or
1202: assembled together at the end of the chapter or even the end of the work. Of
1203: course, this brings up questions of the physical position of elements in
1204: documents that are broken into pages, but this reflects the structural
1205: instability of these elements. They cannot be treated the same way as
1206: elements like paragraphs or sections, whose position in the structure is
1.18 cvs 1207: directly linked to the semantics of the document.</p>
1208: <p>
1.1 cvs 1209: Those elements whose position in the structure of the document is not fixed,
1210: even though they are definitely part of the document, are called
1.18 cvs 1211: <em>associated elements</em>. Associated elements are themselves structures,
1.1 cvs 1212: which is to say that their content can be organized logically by the
1.18 cvs 1213: constructors from primitive and constructed elements.</p>
1214: <p>
1.1 cvs 1215: It can happen that the associated elements are totally disconnected from the
1216: structure of the document, as in a commentary or appraisal of the entire work.
1217: But more often, the associated elements are linked to the content of the
1218: document by references. This is generally the case for notes and figures,
1.18 cvs 1219: among others.</p>
1220: <p>
1.1 cvs 1221: Thus, associated elements introduce a new use for the reference constructor.
1222: It not only serves to create links between elements of the principal structure
1223: of the document, but also serves to link the associated elements to the
1.18 cvs 1224: primary structure.</p>
1225: </div>
1.1 cvs 1226:
1.18 cvs 1227: <div class="subsection">
1.1 cvs 1228:
1.18 cvs 1229: <h3><a name="sectc315">Attributes</a></h3>
1230: <p>
1.1 cvs 1231: There remain logical aspects of documents that are not entirely described by
1232: the structure. Certain types of semantic information, which are not stated
1233: explicitly in the text, must also be taken into account. In particular, such
1234: information is shown by typographic effects which do not correspond to a
1235: change between structural elements. In fact, certain titles are set in bold
1236: or italic or are printed in a different typeface from the rest of the text in
1237: order to mark them as structurally distinct. But these same effects
1238: frequently appear in the middle of continuous text (e.g. in the interior of a
1239: paragraph). In this case, there is no change between structural elements; the
1240: effect serves to highlight a word, expression, or phrase. The notion of an
1.18 cvs 1241: <em>attribute</em> is used to express this type of information.</p>
1242: <p>
1.1 cvs 1243: An attribute is a piece of information attached to a structural element which
1244: augments the type of the element and clarifies its function in the document.
1245: Keywords, foreign language words, and titles of other works can all be
1246: represented by character strings with attached attributes. Attributes may
1247: also be attached to constructed elements. Thus, an attribute indicating the
1248: language can be attached to a single word or to a large part of a
1.18 cvs 1249: document.</p>
1250: <p>
1.1 cvs 1251: In fact, an attribute can be any piece of information which is linked to a
1252: part of a document and which can be used by agents which work on the document.
1253: For example, the language in which the document is written determines the set
1254: of characters used by an editor or formatter. It also determines the
1255: algorithm or hyphenation dictionary to be used. The attribute ``keyword''
1256: facilitates the work of an information retrieval system. The attribute
1257: ``index word'' allows a formatter to automatically construct an index at the
1.18 cvs 1258: end of the document.</p>
1259: <p>
1.1 cvs 1260: As with the types of constructed elements, the attributes and the values they
1261: can take are defined separately in each generic logical structure, not in the
1262: meta-model, according to the needs of the document class or the nature of the
1.18 cvs 1263: object.</p>
1264: <p>
1.1 cvs 1265: Many types of attributes are offered: numeric, textual, references, and
1.18 cvs 1266: enumerations:</p>
1267: <ul>
1268: <li>
1269: <em>Numeric attributes</em> can take integer values (negative, positive, or
1270: null).
1.19 cvs 1271: </li>
1.18 cvs 1272: <li>
1273: <em>Textual attributes</em> have as their values character strings.
1.19 cvs 1274: </li>
1.18 cvs 1275: <li>
1276: <em>Reference attributes</em> designate an element of the logical structure.
1.19 cvs 1277: </li>
1.18 cvs 1278: <li>
1279: <em>Enumeration attributes</em> can take one value from a limited list of
1.1 cvs 1280: possible values, each value being a name.
1.19 cvs 1281: </li>
1.18 cvs 1282: </ul>
1283: <p>
1284: In a generic structure, there is a distinction between <em>global
1285: attributes</em> and <em>local attributes</em>. A global attribute can be
1.1 cvs 1286: applied to every element type defined in the generic structure where it is
1287: specified. In contrast, a local attribute can only be applied to certain
1288: types of elements, even only a single type. The ``language'' attribute
1289: presented above is an example of a global attribute. An example of a local
1290: attribute is the rank of an author (principal author of the document or
1291: secondary author): this attribute can only be applied sensibly to an element
1.18 cvs 1292: of the ``author'' type.</p>
1293: <p>
1.1 cvs 1294: Attributes can be assigned to the elements which make up the document in many
1295: different ways. The author can freely and dynamically place them on any part
1.18 cvs 1296: of the document in order to attach supplementary information of his/her
1297: choice. However, attributes may only be assigned in accordance with the rules
1298: of the generic structure; in particular, local attributes can only be assigned
1299: to those element types for which they are defined.</p>
1300: <p>
1.1 cvs 1301: In the generic structure, certain local attributes can be made mandatory for
1.2 cvs 1302: certain element types. In this case, Thot automatically associates the
1303: attribute with the elements of this type and it requires the user to provide a
1.18 cvs 1304: value for this attribute.</p>
1305: <p>
1.1 cvs 1306: Attributes can also be automatically assigned, with a given value, by every
1307: application processing the document in order to systematically add a piece of
1308: information to certain predefined elements of the document. By way of
1309: example, in a report containing a French abstract and an English abstract,
1310: each of the two abstracts is defined as a sequence of paragraphs. The first
1311: abstract has a value of ``French'' for the ``language'' attribute while the
1.18 cvs 1312: second abstract's ``language'' attribute has a value of ``English''.</p>
1313: <p>
1.1 cvs 1314: In the case of mark pairs, attributes are logically associated with the pair
1.18 cvs 1315: as a whole, but are actually attached to the first mark.</p>
1316: </div>
1.1 cvs 1317:
1.18 cvs 1318: <div class="subsection">
1.1 cvs 1319:
1.18 cvs 1320: <h3><a name="sectc316">Discussion of the model</a></h3>
1321: <p>
1.1 cvs 1322: The notions of attribute, constructor, structured element, and associated
1323: element are used in the definition of generic logical structures of documents
1324: and objects. The problem is to assemble them to form generic structures. In
1325: fact, many types of elements and attributes can be found in a variety of
1326: generic structures. Rather than redefine them for each structure in which
1327: they appear, it is best to share them between structures. The object classes
1328: already fill this sharing function. If a mathematical class is defined, its
1329: formulas can be used in many different document classes, without redefining
1330: the structure of each class. This problem arises not only for the objects
1331: considered here; it also arises for the commonplace textual elements found in
1332: many document classes. This is the reason why the notion of object is so
1333: broad and why paragraphs and enumerations are also considered to be objects.
1334: These object classes not only permit the sharing of the structures of
1.18 cvs 1335: elements, but also of the attributes defined in the generic structures.</p>
1336: <p>
1.1 cvs 1337: Structure, such as that presented here, can appear very rigid, and it is
1338: possible to imagine that a document editing system based on this model could
1339: prove very constraining to the user. This is, in fact, a common criticism of
1340: syntax-directed editors. This defect can be avoided with Thot, primarily for
1.18 cvs 1341: three reasons:</p>
1342: <ul>
1343: <li>
1344: the generic structures are not fixed in the model itself,
1.19 cvs 1345: </li>
1.18 cvs 1346: <li>
1347: the model takes the dynamics of documents into account,
1.19 cvs 1348: </li>
1.18 cvs 1349: <li>
1350: the constructors offer great flexibility.
1.19 cvs 1351: </li>
1.18 cvs 1352: </ul>
1353: <p>
1.1 cvs 1354: When the generic structure of a document is not predefined, but rather is
1355: constructed specifically for each document class, it can be carefully adapted
1356: to the current needs. In cases where the generic structure is inadequate for
1357: a particular document of the class, it is always possible either to create a
1358: new class with a generic structure well suited to the new case or to extend
1359: the generic structure of the existing class to take into account the specifics
1360: of the document which poses the problem. These two solutions can also be
1.18 cvs 1361: applied to objects whose structures prove to be poorly designed.</p>
1362: <p>
1.1 cvs 1363: The model is sufficiently flexible to take into account all the phases of the
1364: life of the document. When a generic structure specifies that a report must
1365: contain a title, an abstract, an introduction, at least two chapters, and a
1.18 cvs 1366: conclusion, this means only that a report, <em>upon completion</em>, will have
1.1 cvs 1367: to contain all of these elements. When the author begins writing, none of
1.2 cvs 1368: these elements is present. Thot uses this model. Therefore, it tolerates
1369: documents which do not conform strictly to the generic structure of their
1370: class; it also considers the generic logical structure to be a way of helping
1.18 cvs 1371: the user in the construction of a complex document.</p>
1372: <p>
1.1 cvs 1373: In contrast, other applications may reject a document which does not conform
1374: strictly to its generic structure. This is, for example, what is done by
1375: compilers which refuse to generate code for a program which is not
1376: syntactically correct. This might also occur when using a document
1.18 cvs 1377: application for a report which does not have an abstract or title.</p>
1378: <p>
1.1 cvs 1379: The constructors of the document model bring a great flexibility to the
1380: generic structures. A choice constructor (and even more, a unit or schema
1381: constructor) can represent several, very different elements. The list
1382: constructor permits the addition of more elements of the same type. Used
1383: together, these two constructors permit any series of elements of different
1384: types. Of course, this flexibility can be reduced wherever necessary since a
1385: generic structure can limit the choices or the number of elements in a
1.18 cvs 1386: list.</p>
1387: <p>
1.1 cvs 1388: Another difficulty linked to the use of structure in the document model
1389: resides in the choice of the level of the structure. The structure of a
1390: discussion could be extracted from the text itself via linguistic analysis.
1391: Some studies are exploring this approach, but the model of Thot excludes this
1392: type of structure. It only takes into account the logical structure provided
1.18 cvs 1393: explicitly by the author.</p>
1394: <p>
1.1 cvs 1395: However, the level of structure of the model is not imposed. Each generic
1396: structure defines its own level of structure, adapted to the document class or
1397: object and to the ways in which it will be processed. If it will only be
1398: edited and printed, a relatively simple structure suffices. If more
1399: specialized processing will be applied to it, the structure must represent the
1400: element types on which this processing must act. By way of example, a simple
1401: structure is sufficient for printing formulas, but a more complex structure is
1402: required to perform symbolic or numeric calculations on the mathematical
1.18 cvs 1403: expressions. The document model of Thot allows both types of structure.</p>
1404: </div>
1405: </div>
1.1 cvs 1406:
1.18 cvs 1407: <div class="section">
1.1 cvs 1408:
1.18 cvs 1409: <h2><a name="sectb32">The definition language for generic structures</a></h2>
1410: <p>
1.1 cvs 1411: Generic structures, which form the basis of the document model of Thot, are
1412: specified using a special language. This definition language, called S, is
1.18 cvs 1413: described in this section.</p>
1414: <p>
1.1 cvs 1415: Each generic structure, which defines a class of documents or objects, is
1.2 cvs 1416: specified by a file, written in the S language, which is called a
1.18 cvs 1417: <em>structure schema</em>. Structure schemas are compiled into tables, called
1418: structure tables, which are used by Thot and which determine its behavior.</p>
1.1 cvs 1419:
1.18 cvs 1420: <div class="subsection">
1.1 cvs 1421:
1.18 cvs 1422: <h3><a name="sectc321">Writing Conventions</a></h3>
1423: <p>
1.1 cvs 1424: The grammar of S, like those of the languages P and T presented later, is
1425: described using the meta-language M, derived from the Backus-Naur Form
1.18 cvs 1426: (BNF).</p>
1427: <p>
1.1 cvs 1428: In this meta-language each rule of the grammar is composed of a grammar symbol
1429: followed by an equals sign (`=') and the right part of the rule. The equals
1430: sign plays the same role as the traditional `::=' of BNF: it indicates that
1.18 cvs 1431: the right part defines the symbol of the left part. In the right part,</p>
1432: <dl>
1433: <dt>concatenation</dt>
1434: <dd>
1435: is shown by the juxtaposition of symbols;
1436: </dd>
1437: <dt>character strings</dt>
1438: <dd>
1439: between apostrophes ' represent terminal symbols, that is, keywords in the
1.2 cvs 1440: language defined. Keywords are written here in upper-case letters, but can be
1441: written in any combination of upper and lower-case letters. For example, the
1.18 cvs 1442: keyword <tt>DEFPRES</tt> of S can also be written as <tt>defpres</tt> or
1443: <tt>DefPres</tt>.
1444: </dd>
1445: <dt>material between brackets</dt>
1446: <dd>
1447: (`[' and `]') is optional;
1448: </dd>
1449: <dt>material between angle brackets</dt>
1450: <dd>
1451: (`<' and `>') can be repeated many times or omitted;
1452: </dd>
1453: <dt>the slash</dt>
1454: <dd>
1455: (`/') indicates an alternative, a choice between the options separated by the
1456: slash character;
1457: </dd>
1458: <dt>the period</dt>
1459: <dd>
1460: marks the end of a rule;
1461: </dd>
1462: <dt>text between braces</dt>
1463: <dd>
1464: (`{' and `}') is simply a comment.
1465: </dd>
1466: </dl>
1467: <p>
1.1 cvs 1468: The M meta-language also uses the concepts of identifiers, strings, and
1.18 cvs 1469: integers:</p>
1470: <dl>
1471: <dt><tt>NAME</tt></dt>
1472: <dd>
1473: represents an identifier, a sequence of letters (upper or lower-case), digits,
1474: and underline characters (`_'), beginning with a letter. Also considered a
1475: letter is the sequence of characters `<tt>\nnn</tt>' where the letter
1476: <tt>n</tt> represents the ISO Latin-1 code of the letter in octal. It is thus
1477: possible to use accented letters in identifiers. The maximum length of
1478: identifiers is fixed by the compiler. It is normally 31 characters.
1479: <p>
1.1 cvs 1480: Unlike keywords, upper and lower-case letters are distinct in identifiers.
1.18 cvs 1481: Thus, <tt>Title</tt>, <tt>TITLE</tt>, and <tt>title</tt> are considered
1482: different identifiers.</p>
1483: </dd>
1484: <dt><tt>STRING</tt></dt>
1485: <dd>
1486: represents a string. This is a string of characters delimited by apostrophes.
1487: If an apostrophe must appear in a string, it is doubled. As with identifiers,
1488: strings can contain characters represented by their octal code (after a
1489: backslash). As with apostrophes, if a backslash must appear in a string, it
1490: is doubled.
1491: </dd>
1492: <dt><tt>NUMBER</tt></dt>
1493: <dd>
1494: represents a positive integer or zero (without a sign), or said another way, a
1495: sequence of decimal digits.
1496: </dd>
1497: </dl>
1498: <p>
1499: The M language can be used to define itself as follows:</p>
1500: <pre>{ Any text between braces is a comment. }
1.1 cvs 1501: Grammar = Rule < Rule > 'END' .
1502: { The < and > signs indicate zero }
1503: { or more repetitions. }
1504: { END marks the end of the grammar. }
1505: Rule = Ident '=' RightPart '.' .
1506: { The period indicates the end of a rule }
1507: RightPart = RtTerminal / RtIntermed .
1508: { The slash indicates a choice }
1509: RtTerminal ='NAME' / 'STRING' / 'NUMBER' .
1510: { Right part of a terminal rule }
1511: RtIntermed = Possibility < '/' Possibility > .
1512: { Right part of an intermediate rule }
1513: Possibility = ElemOpt < ElemOpt > .
1514: ElemOpt = Element / '[' Element < Element > ']' /
1515: '<' Element < Element > '>' .
1516: { Brackets delimit optional parts }
1517: Element = Ident / KeyWord .
1518: Ident = NAME .
1519: { Identifier, sequence of characters }
1520: KeyWord = STRING .
1521: { Character string delimited by apostrophes }
1.18 cvs 1522: END</pre>
1523: </div>
1.1 cvs 1524:
1.18 cvs 1525: <div class="subsection">
1.1 cvs 1526:
1.18 cvs 1527: <h3><a name="sectc322">Extension schemas</a></h3>
1528: <p>
1.1 cvs 1529: A structure schema defines the generic logical structure of a class of
1530: documents or objects, independent of the operations which can be performed on
1531: the documents. However, certain applications may require particular
1532: information to be represented by the structure for the documents that they
1533: operate on. Thus a document version manager will need to indicate in the
1534: document the parts which belong to one version or another. An indexing system
1535: will add highly-structured index tables as well as the links between these
1.18 cvs 1536: tables and the rest of the document.</p>
1537: <p>
1.2 cvs 1538: Thus, many applications need to extend the generic structure of the documents
1539: on which they operate to introduce new attributes, associated elements or
1.1 cvs 1540: element types. These additions are specific to each application and must be
1541: able to be applied to any generic structure: users will want to manage
1542: versions or construct indices for many types of documents. Extension schemas
1543: fulfill this role: they define attributes, elements, associated elements,
1544: units, etc., but they can only be used jointly with a structure schema that
1545: they complete. Otherwise, structure schemas can always be used without these
1.18 cvs 1546: extensions when the corresponding applications are not available.</p>
1547: </div>
1.1 cvs 1548:
1.18 cvs 1549: <div class="subsection">
1.1 cvs 1550:
1.18 cvs 1551: <h3><a name="sectc323">The general organization of structure schemas</a></h3>
1552: <p>
1553: Every structure schema begins with the keyword <tt>STRUCTURE</tt> and ends
1554: with the keyword <tt>END</tt>. The keyword <tt>STRUCTURE</tt> is followed by
1555: the keyword <tt>EXTENSION</tt> in the case where the schema defines an
1.1 cvs 1556: extension, then by the name of the generic structure which the schema defines
1557: (the name of the document or object class). The name of the structure is
1.18 cvs 1558: followed by a semicolon.</p>
1559: <p>
1.1 cvs 1560: In the case of a complete schema (that is, a schema which is not an
1561: extension), the definition of the name of the structure is followed by the
1562: declarations of the default presentation schema, the global attributes, the
1563: parameters, the structure rules, the associated elements, the units, the
1564: skeleton elements and the exceptions. Only the definition of the structure
1565: rules is required. Each series of declarations begins with a keyword:
1.18 cvs 1566: <tt>DEFPRES</tt>, <tt>ATTR</tt>, <tt>PARAM</tt>, <tt>STRUCT</tt>,
1567: <tt>ASSOC</tt>, <tt>UNITS</tt>, <tt>EXPORT</tt>, <tt>EXCEPT</tt>.</p>
1568: <p>
1.1 cvs 1569: In the case of an extension schema, there are neither parameters nor skeleton
1.18 cvs 1570: elements and the <tt>STRUCT</tt> section is optional, while that section is
1.1 cvs 1571: required in a schema that is not an extension. On the other hand, extension
1.18 cvs 1572: schemas can contain an <tt>EXTENS</tt> section, which must not appear in a
1.1 cvs 1573: schema which is not an extension; this section defines the complements to
1574: attach to the rules found in the schema to which the extension will be added.
1.18 cvs 1575: The sections <tt>ATTR</tt>, <tt>STRUCT</tt>, <tt>ASSOC</tt>, and
1576: <tt>UNITS</tt> define new attributes, new elements, new associated elements,
1577: and new units which add their definitions to the principal schema.</p>
1578: <pre> StructSchema ='STRUCTURE' ElemID ';'
1.1 cvs 1579: 'DEFPRES' PresID ';'
1580: [ 'ATTR' AttrSeq ]
1581: [ 'PARAM' RulesSeq ]
1582: 'STRUCT' RulesSeq
1583: [ 'ASSOC' RulesSeq ]
1584: [ 'UNITS' RulesSeq ]
1585: [ 'EXPORT' SkeletonSeq ]
1586: [ 'EXCEPT' ExceptSeq ]
1587: 'END' .
1.18 cvs 1588: ElemID = NAME .</pre>
1589: <p>
1590: or</p>
1591: <pre> ExtensSchema ='STRUCTURE' 'EXTENSION' ElemID ';'
1.1 cvs 1592: 'DEFPRES' PresID ';'
1593: [ 'ATTR' AttrSeq ]
1594: [ 'STRUCT' RulesSeq ]
1595: [ 'EXTENS' ExtensRuleSeq ]
1596: [ 'ASSOC' RulesSeq ]
1597: [ 'UNITS' RulesSeq ]
1598: [ 'EXCEPT' ExceptSeq ]
1599: 'END' .
1.18 cvs 1600: ElemID = NAME .</pre>
1601: </div>
1.1 cvs 1602:
1.18 cvs 1603: <div class="subsection">
1.1 cvs 1604:
1.18 cvs 1605: <h3><a name="sectc324">The default presentation</a></h3>
1606: <p>
1607: It was shown <a href="#mulpres">above</a> that many different presentations
1.1 cvs 1608: are possible for documents and objects of the same class. The structure
1.18 cvs 1609: schema defines a preferred presentation for the class, called the <em>default
1610: presentation</em>. Like generic structures, presentations are described by
1611: programs, called <em>presentation schemas</em>, which are written in a
1612: specific language, P, presented <a href="#sectb42">later</a> in this document.
1613: The name appearing after the keyword <tt>DEFPRES</tt> is the name of the
1.2 cvs 1614: default presentation schema. When a new document is created, Thot will use
1615: this presentation schema by default, but the user remains free to choose
1.18 cvs 1616: another if s/he wishes.</p>
1617: <pre> PresID = NAME .</pre>
1618: </div>
1.1 cvs 1619:
1.18 cvs 1620: <div class="subsection">
1.1 cvs 1621:
1.18 cvs 1622: <h3><a name="sectc325">Global Attributes</a></h3>
1623: <p>
1.1 cvs 1624: If the generic structure includes global attributes of its own, they are
1.18 cvs 1625: declared after the keyword <tt>ATTR</tt>. Each global attribute is defined by
1.1 cvs 1626: its name, followed by an equals sign and the definition of its type. The
1.18 cvs 1627: declaration of a global attribute is terminated by a semi-colon.</p>
1628: <p>
1.1 cvs 1629: For attributes of the numeric, textual, or reference types, the type is
1.18 cvs 1630: indicated by a keyword, <tt>INTEGER</tt>, <tt>TEXT</tt>, or <tt>REFERENCE</tt>
1631: respectively.</p>
1632: <p>
1633: In the case of a reference attribute, the keyword <tt>REFERENCE</tt> is
1.1 cvs 1634: followed by the type of the referenced element in parentheses. It can refer
1.18 cvs 1635: to any type at all, specified by using the keyword <tt>ANY</tt>, or to a
1.1 cvs 1636: specific type. In the latter case, the element type designated by the
1.18 cvs 1637: reference can be defined either in the <a href="#sectc327"><tt>STRUCT</tt>
1638: section</a> of the same structure schema or in the <tt>STRUCT</tt> section of
1.1 cvs 1639: another structure schema. When the type is defined in another schema, the
1640: element type is followed by the name of the structure schema (within
1641: parentheses) in which it is defined. The name of the designated element type
1.18 cvs 1642: can be preceded by the keyword <tt>First</tt> or <tt>Second</tt>, but only in
1643: the case where the type is defined as <a href="#sectd3285">a pair</a>. These
1.1 cvs 1644: keywords indicate whether the attribute must designate the first mark of the
1645: pair or the second. If the reference refers to a pair and neither of these
1.18 cvs 1646: two keywords is present, then the first mark is used.</p>
1647: <p>
1.1 cvs 1648: In the case of an enumeration attribute, the equals sign is followed by the
1649: list of names representing the possible values of the attribute, the names
1650: being separated from each other by commas. An enumeration attribute has at
1651: least one possible value; the maximum number of values is defined by the
1.18 cvs 1652: compiler for the S language.</p>
1653: <pre> AttrSeq = Attribute < Attribute > .
1.1 cvs 1654: Attribute = AttrID '=' AttrType ';' .
1655: AttrType = 'INTEGER' / 'TEXT' /
1656: 'REFERENCE' '(' RefType ')' /
1657: ValueSeq .
1658: RefType = 'ANY' / [ FirstSec ] ElemID [ ExtStruct ] .
1659: FirstSec = 'First' / 'Second' .
1660: ExtStruct = '(' ElemID ')' .
1661: ValueSeq = AttrVal < ',' AttrVal > .
1662: AttrID = NAME .
1.18 cvs 1663: AttrVal = NAME .</pre>
1664: <p>
1665: There is a predefined global text attribute, the <em>language</em>, which is
1.2 cvs 1666: automatically added to every Thot structure schema. This attribute allows
1667: Thot to perform certain actions, such as hyphenation and spell-checking, which
1668: cannot be performed without knowing the language in which each part of the
1669: document is written. This attribute can be used just like any explicitly
1.18 cvs 1670: declared attribute: the system acts as if every structure schema contains</p>
1671: <pre>ATTR
1672: Language = TEXT;</pre>
1673: <blockquote class="example">
1674: <p>
1675: <strong>Example:</strong></p>
1676: <p>
1.2 cvs 1677: The following specification defines the global enumeration attribute
1.18 cvs 1678: WordType.</p>
1679: <pre>ATTR
1680: WordType = Definition, IndexWord, DocumentTitle;</pre>
1681: </blockquote>
1682: </div>
1.1 cvs 1683:
1.18 cvs 1684: <div class="subsection">
1.1 cvs 1685:
1.18 cvs 1686: <h3><a name="sectc326">Parameters</a></h3>
1687: <p>
1.1 cvs 1688: A parameter is a document element which can appear many times in the document,
1689: but always has the same value. This value can only be modified in a
1690: controlled way by certain applications. For example, in an advertising
1691: circular, the name of the recipient may appear in the address part and in the
1692: text of the circular. If the recipient's name were a parameter, it might only
1.18 cvs 1693: be able to be changed by a ``mail-merge'' application.</p>
1694: <p>
1.1 cvs 1695: Parameters are not needed for every document class, but if the schema includes
1.18 cvs 1696: parameters they are declared after the keyword <tt>PARAM</tt>. Each parameter
1697: declaration is made in the same way as a <a href="#sectc327">structure element
1698: declaration</a>.</p>
1699: <p>
1.1 cvs 1700: During editing, Thot permits the insertion of parameters wherever the
1701: structure schema allows; it also permits the removal of parameters which are
1702: already in the document but does not allow the modification of the parameter's
1.2 cvs 1703: content in any way. The content is generated automatically by Thot during the
1704: creation of the parameter, based on the value of the parameter in the
1.18 cvs 1705: document.</p>
1706: </div>
1.1 cvs 1707:
1.18 cvs 1708: <div class="subsection">
1.1 cvs 1709:
1.18 cvs 1710: <h3><a name="sectc327">Structured elements</a></h3>
1711: <p>
1.1 cvs 1712: The rules for defining structured elements are required, except in an
1713: extension schema: they constitute the core of a structure schema, since they
1714: define the structure of the different types of elements that occur in a
1.18 cvs 1715: document or object of the class defined by the schema.</p>
1716: <p>
1717: The first structure rule after the keyword <tt>STRUCT</tt> must define the
1.1 cvs 1718: structure of the class whose name appears in the first instruction
1.18 cvs 1719: (<tt>STRUCTURE</tt>) of the schema. This is the root rule of the schema,
1720: defining the root of the document tree or object tree.</p>
1721: <p>
1.1 cvs 1722: The remaining rules may be placed in any order, since the language permits the
1723: definition of element types before or after their use, or even in the same
1724: instruction in which they are used. This last case allows the definition of
1.18 cvs 1725: recursive structures.</p>
1726: <p>
1.1 cvs 1727: Each rule is composed of a name (the name of the element type whose structure
1.18 cvs 1728: is being defined) followed by an equals sign and a structure definition.</p>
1729: <p>
1.1 cvs 1730: If any local attributes are associated with the element type defined by the
1.2 cvs 1731: rule, they appear between parentheses after the type name and before the
1.18 cvs 1732: equals sign. The parentheses contain, first, the keyword <tt>ATTR</tt>, then
1.2 cvs 1733: the list of local attributes, separated by commas. Each local attribute is
1734: composed of the name of the attribute followed by an equals sign and the
1.18 cvs 1735: definition of the attribute's type, just as in the definition of <a
1736: href="#sectc325">global attributes</a>. The name of the attribute can be
1.2 cvs 1737: preceded by an exclamation point to indicate that the attribute must always be
1738: present for this element type. The same attribute, identified by its name,
1739: can be defined as a local attribute for multiple element types. In this
1740: case, the equals sign and definition of the attribute type need only appear in
1741: the first occurrence of the attribute. It should be noted that global
1.18 cvs 1742: attributes cannot also be defined as local attributes.</p>
1743: <p>
1744: If any <a href="#sectd3135">extensions</a> are defined for this element type,
1745: a plus sign follows the structure definition and the names of the extension
1746: element types appear between parentheses after the plus. If there are
1747: multiple extensions, they are separated by commas. These types can either be
1748: defined in the same schema, defined in other schemas, or they may be base
1749: types identified by the keywords <tt>TEXT</tt>, <tt>GRAPHICS</tt>,
1750: <tt>SYMBOL</tt>, or <tt>PICTURE</tt>.</p>
1751: <p>
1752: <a href="#sectd3135">Restrictions</a> are indicated in the same manner as
1753: extensions, but they are introduced by a minus sign and they come after the
1754: extensions, or if there are no extensions, after the structure definition.</p>
1755: <p>
1.1 cvs 1756: If the values of attributes must be attached systematically to this element
1.18 cvs 1757: type, they are introduced by the keyword <tt>WITH</tt> and declared in the
1.1 cvs 1758: form of a list of fixed-value attributes. When such definitions of fixed
1.18 cvs 1759: attribute values appear, they are always the last part of the rule.</p>
1760: <p>
1761: The rule is terminated by a semicolon.</p>
1762: <pre> RuleSeq = Rule < Rule > .
1.1 cvs 1763: Rule = ElemID [ LocAttrSeq ] '=' DefWithAttr ';'.
1764: LocAttrSeq = '(' 'ATTR' LocAttr < ';' LocAttr > ')' .
1765: LocAttr = [ '!' ] AttrID [ '=' AttrType ] .
1766: DefWithAttr = Definition
1767: [ '+' '(' ExtensionSeq ')' ]
1768: [ '-' '(' RestrictSeq ')' ]
1769: [ 'WITH' FixedAttrSeq ] .
1770: ExtensionSeq = ExtensionElem < ',' ExtensionElem > .
1771: ExtensionElem = ElemID / 'TEXT' / 'GRAPHICS' /
1772: 'SYMBOL' / 'PICTURE' .
1773: RestrictSeq = RestrictElem < ',' RestrictElem > .
1774: RestrictElem = ElemID / 'TEXT' / 'GRAPHICS' /
1.18 cvs 1775: 'SYMBOL' / 'PICTURE' .</pre>
1776: <p>
1.1 cvs 1777: The list of fixed-value attributes is composed of a sequence of
1778: attribute-value pairs separated by commas. Each pair contains the name of the
1779: attribute and the fixed value for this element type, the two being separated
1780: by an equals sign. If the sign is preceded by a question mark the given value
1781: is only an initial value that may be modified later rather than a value fixed
1782: for all time. Reference attributes are an exception to this norm. They
1783: cannot be assigned a fixed value, but when the name of such an attribute
1784: appears this indicates that this element type must have a valid value for the
1.2 cvs 1785: attribute. For the other attribute types, the fixed value is indicated by a
1.1 cvs 1786: signed integer (numeric attributes), a character string between apostrophes
1.18 cvs 1787: (textual attributes) or the name of a value (enumeration attributes).</p>
1788: <p>
1789: Fixed-value attributes can either be <a href="#sectc325">global</a> or local
1.1 cvs 1790: to the element type for which they are fixed, but they must be declared before
1.18 cvs 1791: they are used.</p>
1792: <pre> FixedAttrSeq = FixedAttr < ',' FixedAttr > .
1.1 cvs 1793: FixedAttr = AttrID [ FixedOrModifVal ] .
1794: FixedOrModifVal = [ '?' ] '=' FixedValue .
1795: FixedValue = [ '-' ] NumValue / TextVal / AttrVal .
1796: NumValue = NUMBER .
1.18 cvs 1797: TextVal = STRING .</pre>
1798: </div>
1.1 cvs 1799:
1.18 cvs 1800: <div class="subsection">
1.1 cvs 1801:
1.18 cvs 1802: <h3><a name="sectc328">Structure definitions</a></h3>
1803: <p>
1.1 cvs 1804: The structure of an element type can be a simple base type or a constructed
1.18 cvs 1805: type.</p>
1806: <p>
1.1 cvs 1807: For constructed types, it is frequently the case that similar structures
1808: appear in many places in a document. For example the contents of the
1809: abstract, of the introduction, and of a section can have the same structure,
1810: that of a sequence of paragraphs. In this case, a single, common structure
1811: can be defined (the paragraph sequence in this example), and the schema is
1812: written to indicate that each element type possesses this structure, as
1.18 cvs 1813: follows:</p>
1814: <pre> Abstract = Paragraph_sequence;
1.1 cvs 1815: Introduction = Paragraph_sequence;
1.18 cvs 1816: Section_contents = Paragraph_sequence;</pre>
1817: <p>
1818: The equals sign means ``has the same structure as''.</p>
1819: <p>
1.1 cvs 1820: If the element type defined is a simple base type, this is indicated by one of
1.18 cvs 1821: the keywords <tt>TEXT</tt>, <tt>GRAPHICS</tt>, <tt>SYMBOL</tt>, or
1822: <tt>PICTURE</tt>. If some local attributes must be associated with a base
1.1 cvs 1823: type, the keyword of the base type is followed by the declaration of the local
1.18 cvs 1824: attributes using the syntax <a href="#sectc327">presented above.</a></p>
1825: <p>
1.1 cvs 1826: In the case of an open choice, the type is indicated by the keyword
1.18 cvs 1827: <tt>UNIT</tt> for units or the keyword <tt>NATURE</tt> for objects having a
1828: structure defined by any other schema.</p>
1829: <p>
1830: A unit represents one of the two following categories:</p>
1831: <ul>
1832: <li>
1833: a base type: text, graphical element, symbol, picture,
1.19 cvs 1834: </li>
1.18 cvs 1835: <li>
1836: an element whose type is chosen from among the types defined as units in the
1837: <tt>UNITS</tt> section of the document's structure schema. It can also be
1838: chosen from among the types defined as <a href="#sectd3132">units</a> in the
1839: <a href="#sectc3212"><tt>UNITS</tt> section</a> of the structure schemas that
1.2 cvs 1840: defines the ancestors of the element to which the rule is applied.
1.19 cvs 1841: </li>
1.18 cvs 1842: </ul>
1843: <p>
1.2 cvs 1844: Before the creation of an element defined as a unit, Thot asks the user to
1.18 cvs 1845: choose between the categories of elements.</p>
1846: <p>
1.1 cvs 1847: Thus, the contents of a paragraph can be specified as a sequence of units,
1848: which will permit the inclusion in the paragraphs of character strings,
1849: symbols, and various elements, such as cross-references, if these are defined
1.18 cvs 1850: as units.</p>
1851: <p>
1852: A schema object (keyword <tt>NATURE</tt>) represents an object defined by a
1.1 cvs 1853: structure schema freely chosen from among the available schemas; in the case
1854: the element type is defined by the first rule (the root rule) of the chosen
1.18 cvs 1855: schema.</p>
1856: <p>
1.1 cvs 1857: If the element type defined is a constructed type, the list, aggregate,
1858: choice, and reference constructors are used. In this case the definition
1859: begins with a keyword identifying the constructor. This keyword is followed
1.18 cvs 1860: by a syntax specific to each constructor.</p>
1861: <p>
1.1 cvs 1862: The local attribute definitions appear after the name of the element type
1.18 cvs 1863: being defined, if this element type has <a href="#sectc327">local
1864: attributes</a>.</p>
1865: <pre> Definition = BaseType [ LocAttrSeq ] / Constr / Element .
1.1 cvs 1866: BaseType = 'TEXT' / 'GRAPHICS' / 'SYMBOL' / 'PICTURE' /
1867: 'UNIT' / 'NATURE' .
1868: Element = ElemID [ ExtOrDef ] .
1869: ExtOrDef = 'EXTERN' / 'INCLUDED' /
1870: [ LocAttrSeq ] '=' Definition .
1871: Constr = 'LIST' [ '[' min '..' max ']' ] 'OF'
1872: '(' DefWithAttr ')' /
1873: 'BEGIN' DefOptSeq 'END' /
1874: 'AGGREGATE' DefOptSeq 'END' /
1875: 'CASE' 'OF' DefSeq 'END' /
1876: 'REFERENCE' '(' RefType ')' /
1.18 cvs 1877: 'PAIR' .</pre>
1.1 cvs 1878:
1.18 cvs 1879: <div class="subsubsection">
1.1 cvs 1880:
1.18 cvs 1881: <h4><a name="sectd3281">List</a></h4>
1882: <p>
1.1 cvs 1883: The list constructor permits the definition of an element type composed of a
1884: list of elements, all of the same type. A list definition begins with the
1.18 cvs 1885: <tt>LIST</tt> keyword followed by an optional range, the keyword <tt>OF</tt>,
1.1 cvs 1886: and the definition, between parentheses, of the element type which must
1887: compose the list. The optional range is composed of the minimum and maximum
1888: number of elements for the list separated by two periods and enclosed by
1889: brackets. If the range is not present, the number of list elements is
1890: unconstrained. When only one of the two bounds of the range is unconstrained,
1891: it is represented by a star ('*') character. Even when both bounds are
1.18 cvs 1892: unconstrained, they can be specified by <tt>[*..*]</tt>, but it is simpler not
1893: to specify any bound.</p>
1894: <pre> 'LIST' [ '[' min '..' max ']' ]
1.1 cvs 1895: 'OF' '(' DefWithAttr ')'
1896: min = Integer / '*' .
1897: max = Integer / '*' .
1.18 cvs 1898: Integer = NUMBER .</pre>
1899: <p>
1.2 cvs 1900: Before the document is edited, Thot creates the minimum number of elements for
1901: the list. If no minimum was given, it creates a single element. If a maximum
1902: number of elements is given and that number is attained, the editor refuses to
1.18 cvs 1903: create new elements for the list.</p>
1904: <blockquote class="example">
1905: <p>
1906: <strong>Example:</strong></p>
1907: <p>
1.3 cvs 1908: The following two instructions define the body of a document as a sequence of
1909: at least two chapters and the contents of a section as a sequence of
1.18 cvs 1910: paragraphs. A single paragraph can be the entire contents of a section.</p>
1911: <pre>Body = LIST [2..*] OF (Chapter);
1912: Section_contents = LIST OF (Paragraph);</pre>
1913: </blockquote>
1914: </div>
1.1 cvs 1915:
1.18 cvs 1916: <div class="subsubsection">
1.1 cvs 1917:
1.18 cvs 1918: <h4><a name="sectd3282">Aggregate</a></h4>
1919: <p>
1.1 cvs 1920: The aggregate constructor is used to define an element type as a collection of
1921: sub-elements, each having a fixed type. The collection may be ordered or
1922: unordered. The elements composing the collection are called
1.18 cvs 1923: <em>components</em>. In the definition of an aggregate, a keyword indicates
1924: whether or not the aggregate is ordered: <tt>BEGIN</tt> for an ordered
1925: aggregate, <tt>AGGREGATE</tt> for an unordered aggregate. This keyword is
1.1 cvs 1926: followed by the list of component type definitions which is terminated by the
1.18 cvs 1927: <tt>END</tt> keyword. The component type definitions are separated by
1928: commas.</p>
1929: <p>
1.1 cvs 1930: Before creating an aggregate, the Thot editor creates all the aggregate's
1931: components in the order they appear in the structure schema, even for
1932: unordered aggregates. However, unlike ordered aggregates, the components of
1933: an unordered aggregate may be rearranged using operations of the Thot editor.
1934: The exceptions to the rule are any components whose name was preceded by a
1935: question mark character ('?'). These components, which are optional, can be
1936: created by explicit request, possibly at the time the aggregate is created,
1.18 cvs 1937: but they are not created automatically <em>prior</em> to the creation of the
1938: aggregate.</p>
1939: <pre> 'BEGIN' DefOptSeq 'END'
1.1 cvs 1940: DefOptSeq = DefOpt ';' < DefOpt ';' > .
1.18 cvs 1941: DefOpt = [ '?' ] DefWithAttr .</pre>
1942: <blockquote class="example">
1943: <p>
1944: <strong>Example:</strong></p>
1945: <p>
1.3 cvs 1946: In a bilingual document, each paragraph has an English version and a French
1947: version. In certain cases, the translator wants to add a marginal note, but
1948: this note is present in very few paragraphs. Thus, it must not be created
1949: systematically for every paragraph. A bilingual paragraph of this type is
1.18 cvs 1950: declared:</p>
1951: <pre>Bilingual_paragraph = BEGIN
1.1 cvs 1952: French_paragraph = TEXT;
1953: English_paragraph = TEXT;
1954: ? Note = TEXT;
1.18 cvs 1955: END;</pre>
1956: </blockquote>
1957: </div>
1.1 cvs 1958:
1.18 cvs 1959: <div class="subsubsection">
1.1 cvs 1960:
1.18 cvs 1961: <h4><a name="sectd3283">Choice</a></h4>
1962: <p>
1.1 cvs 1963: The choice constructor permits the definition of an element type which is
1.18 cvs 1964: chosen from among a set of possible types. The keywords <tt>CASE</tt> and
1965: <tt>OF</tt> are followed by a list of definitions of possible types, which are
1966: separated by semicolons and terminated by the <tt>END</tt> keyword.</p>
1967: <pre> 'CASE' 'OF' DefSeq 'END'
1968: DefSeq = DefWithAttr ';' < DefWithAttr ';' > .</pre>
1969: <p>
1.1 cvs 1970: Before the creation of an element defined as a choice, the Thot editor
1971: presents the list of possible types for the element to the user. The user has
1.18 cvs 1972: only to select the element type that s/he wants to create from this list.</p>
1973: <p>
1.1 cvs 1974: The order of the type declarations is important. It determines the order of
1975: the list presented to the user before the creation of the element. Also, when
1976: a Choice element is being created automatically, the first type in the list is
1977: used. In fact, using the Thot editor, when an empty Choice element is
1978: selected, it is possible to select this element and to enter its text from
1979: keyboard. In this case, the editor uses the first element type which can
1.18 cvs 1980: contain an atom of the character string type.</p>
1981: <p>
1982: The two special cases of the choice constructor, the <a
1983: href="#sectc328"><em>schema</em></a> and the <a
1984: href="#sectc3212"><em>unit</em></a> are discussed elsewhere.</p>
1985: <blockquote class="example">
1986: <p>
1987: <strong>Example:</strong></p>
1988: <p>
1.3 cvs 1989: It is common in documents to treat a variety of objects as if they were
1990: ordinary paragraphs. Thus, a ``Paragraph'' might actually be composed of a
1991: block of text (an ordinary paragraph), or a mathematical formula whose
1992: structure is defined by another structure schema named Math, or a table, also
1993: defined by another structure schema. Here is a definition of such a
1.18 cvs 1994: paragraph:</p>
1995: <pre>Paragraph = CASE OF
1.1 cvs 1996: Simple_text = TEXT;
1997: Formula = Math;
1998: Table_para = Table;
1.18 cvs 1999: END;</pre>
2000: </blockquote>
2001: </div>
1.1 cvs 2002:
1.18 cvs 2003: <div class="subsubsection">
1.1 cvs 2004:
1.18 cvs 2005: <h4><a name="sectd3284">Reference</a></h4>
2006: <p>
1.1 cvs 2007: Like all elements in Thot, references are typed. An element type defined as a
2008: reference is a cross-reference to an element of some other given type. The
1.18 cvs 2009: keyword <tt>REFERENCE</tt> is followed by the name of a type enclosed in
1.1 cvs 2010: parentheses. When the type which is being cross-referenced is defined in
2011: another structure schema, the type name is itself followed by the name of the
1.18 cvs 2012: external structure schema in which it is defined.</p>
2013: <p>
2014: When the designated element type is a <a href="#sectd3285">mark pair</a>, it
2015: can be preceded by a <tt>FIRST</tt> or <tt>SECOND</tt> keyword. These
2016: keywords indicate whether the reference points to the first or second mark of
2017: the pair. If the reference points to a pair and neither of these two keywords
2018: is present, the reference is considered to point to the first mark of the
2019: pair.</p>
2020: <p>
1.1 cvs 2021: There is an exception to the principle of typed references: it is possible to
2022: define a reference which designates an element of any type, which can either
2023: be in the same document or another document. In this case, it suffices to put
1.18 cvs 2024: the keyword <tt>ANY</tt> in the parentheses which indicate the referenced
2025: element type.</p>
2026: <pre> 'REFERENCE' '(' RefType ')'
2027: RefType = 'ANY' / [ FirstSec ] ElemID [ ExtStruct ] .</pre>
2028: <p>
2029: When defining an inclusion, the <tt>REFERENCE</tt> keyword is not used.
1.1 cvs 2030: Inclusions with complete expansion are not declared as such in the structure
2031: schemas, since any element defined in a structure schema can be replaced by an
2032: element of the same type. Instead, inclusions without expansion or with
2033: partial expansion must be declared explicitly whenever they will include a
2034: complete object ( and not a part of an object). In this case, the object type
2035: to be included (that is, the name of its structure schema) is followed by a
1.18 cvs 2036: keyword: <tt>EXTERN</tt> for inclusion without expansion and <tt>INCLUDED</tt>
2037: for partial expansion.</p>
2038: <p>
1.1 cvs 2039: Before creating a cross-reference or an inclusion, the Thot editor asks the
2040: user to choose, from the document images displayed, the referenced or included
1.18 cvs 2041: element.</p>
2042: <blockquote class="example">
2043: <p>
2044: <strong>Example:</strong></p>
2045: <p>
1.3 cvs 2046: If the types Note and Section are defined in the Article structure schema, it
2047: is possible to define, in the same structure schema, a reference to a note and
1.18 cvs 2048: a reference to a section in this manner:</p>
2049: <pre>Ref_note = REFERENCE (Note);
2050: Ref_section = REFERENCE (Section);</pre>
2051: <p>
1.1 cvs 2052: It is also possible to define the generic structure of a collection of
2053: articles, which include (with partial expansion) objects of the Article class
2054: and which possess an introduction which may include cross-references to
2055: sections of the included articles. In the Collection structure schema, the
1.18 cvs 2056: definitions are:</p>
2057: <pre>Collection = BEGIN
1.6 cvs 2058: Collection_title = TEXT;
2059: Introduction = LIST OF (Elem = CASE OF
1.1 cvs 2060: TEXT;
2061: Ref_sect;
2062: END);
1.6 cvs 2063: Body = LIST OF (Article INCLUDED);
2064: END;
1.18 cvs 2065: Ref_sect = REFERENCE (Section (Article));</pre>
2066: <p>
1.1 cvs 2067: Here we define a Folder document class which has a title and includes
1.18 cvs 2068: documents of different types, particularly Folders:</p>
2069: <pre>Folder = BEGIN
1.6 cvs 2070: Folder_title = TEXT;
2071: Folder_contents = LIST OF (Document);
2072: END;
1.1 cvs 2073:
2074: Document = CASE OF
2075: Article EXTERN;
2076: Collection EXTERN;
2077: Folder EXTERN;
1.18 cvs 2078: END;</pre>
2079: <p>
1.1 cvs 2080: Under this definition, Folder represents either an aggregate which contains a
2081: folder title and the list of included documents or an included folder. To
2082: resolve this ambiguity, in the P language, the placement of a star character
1.18 cvs 2083: in front of the type name (here, Folder) indicates an included document.</p>
2084: </blockquote>
2085: </div>
1.1 cvs 2086:
1.18 cvs 2087: <div class="subsubsection">
1.1 cvs 2088:
1.18 cvs 2089: <h4><a name="sectd3285">Mark pairs</a></h4>
2090: <p>
1.1 cvs 2091: Like other elements, mark pairs are typed. The two marks of the pair have the
2092: same type, but there exist two predefined subtypes which apply to all mark
1.18 cvs 2093: pairs: the first mark of the pair (called <tt>First</tt> in the P and T
2094: languages) and the second mark (called <tt>Second</tt>).</p>
2095: <p>
2096: In the S language, a mark pair is noted simply by the <tt>PAIR</tt>
2097: keyword.</p>
2098: <p>
1.1 cvs 2099: In the Thot editor, marks are always moved or destroyed together. The two
2100: marks of a pair have the same identifier, unique within the document, which
1.18 cvs 2101: permits intertwining mark pairs without risk of ambiguity.</p>
2102: </div>
2103: </div>
1.1 cvs 2104:
1.18 cvs 2105: <div class="subsection">
1.1 cvs 2106:
1.18 cvs 2107: <h3><a name="sectc329">Imports</a></h3>
2108: <p>
1.1 cvs 2109: Because of schema constructors, it is possible, before editing a document, to
2110: use classes defined by other structure schemas whenever they are needed. It is
2111: also possible to assign specific document classes to certain element types. In
2112: this case, these classes are simply designated by their name. In fact, if a
2113: type name is not defined in the structure schema, it is assumed that it
1.18 cvs 2114: specifies a structure defined by another structure schema.</p>
2115: <blockquote class="example">
2116: <p>
2117: <strong>Example:</strong></p>
2118: <p>
1.3 cvs 2119: If the types Math and Table don't appear in the left part of a structure rule
2120: in the schema, the following two rules indicate that a formula has the
2121: structure of an object defined by the structure schema Math and that a table
1.18 cvs 2122: element has the structure of an object defined by the Table schema.</p>
2123: <pre>Formula = Math;
2124: Table_elem = Table;</pre>
2125: </blockquote>
2126: </div>
2127:
2128: <div class="subsection">
2129:
2130: <h3><a name="sectc3210">Extension rules</a></h3>
2131: <p>
2132: The <tt>EXTENS</tt> section, which can only appear in an extension schema,
1.1 cvs 2133: defines complements to the rules in the primary schema (i.e. the structure
2134: schema to which the extension schema will be applied). More precisely, this
2135: section permits the addition to an existing type of local attributes,
1.18 cvs 2136: extensions, restrictions and fixed-value attributes.</p>
2137: <p>
1.1 cvs 2138: These additions can be applied to the root rule of the primary schema,
1.18 cvs 2139: designated by the keyword <tt>Root</tt>, or to any other explicitly named
2140: rule.</p>
2141: <p>
1.1 cvs 2142: Extension rules are separated from each other by a semicolon and each
1.18 cvs 2143: extension rule has the same syntax as a <a href="#sectc327">structure
2144: rule</a>, but the part which defines the constructor is absent.</p>
2145: <pre> ExtenRuleSeq = ExtensRule ';' < ExtensRule ';' > .
1.6 cvs 2146: ExtensRule = RootOrElem [ LocAttrSeq ]
2147: [ '+' '(' ExtensionSeq ')' ]
2148: [ '-' '(' RestrictSeq ')' ]
2149: [ 'WITH' FixedAttrSeq ] .
1.18 cvs 2150: RootOrElem = 'Root' / ElemID .</pre>
2151: </div>
1.1 cvs 2152:
1.18 cvs 2153: <div class="subsection">
1.1 cvs 2154:
1.18 cvs 2155: <h3><a name="sectc3211">Associated elements</a></h3>
2156: <p>
1.1 cvs 2157: If associated elements are necessary, they must be declared in a specific
1.18 cvs 2158: section of the structure schema, introduced by the keyword <tt>ASSOC</tt>.
1.1 cvs 2159: Each associated element type is specified like any other structured element.
2160: However, these types must not appear in any other element types of the schema,
1.18 cvs 2161: except in <tt>REFERENCE</tt> rules.</p>
2162: </div>
1.1 cvs 2163:
1.18 cvs 2164: <div class="subsection">
1.1 cvs 2165:
1.18 cvs 2166: <h3><a name="sectc3212">Units</a></h3>
2167: <p>
2168: The <tt>UNITS</tt> section of the structure schema contains the declarations
1.1 cvs 2169: of the element types which can be used in the external objects making up parts
2170: of the document or in objects of the class defined by the schema. As with
2171: associated elements, these element types are defined just like other
2172: structured element types. They can be used in the other element types of the
1.18 cvs 2173: schema, but they can also be used in any other rule of the schema.</p>
2174: <blockquote class="example">
2175: <p>
2176: <strong>Example:</strong></p>
2177: <p>
2178: If references to notes are declared as units:</p>
2179: <pre>UNITS
2180: Ref_note = REFERENCE (Note);</pre>
2181: <p>
1.3 cvs 2182: then it is possible to use references to notes in a cell of a table, even when
1.18 cvs 2183: <tt>Table</tt> is an external structure schema. The <tt>Table</tt> schema
2184: must declare a cell to be a sequence of units, which can then be base element
2185: types (text, for example) or references to notes in the document.</p>
2186: <pre>Cell = LIST OF (UNITS);</pre>
2187: </blockquote>
2188: </div>
1.1 cvs 2189:
1.18 cvs 2190: <div class="subsection">
1.1 cvs 2191:
1.18 cvs 2192: <h3><a name="sectc3213">Skeleton elements</a></h3>
2193: <p>
1.1 cvs 2194: When editing a document which contains or must contain external references to
2195: several other documents, it may be necessary to load a large number of
2196: documents, simply to see the parts designated by the external references of
2197: the document while editing, or to access the source of included elements. In
2198: this case, the external documents are not modified and it is only necessary to
2199: see the elements of these documents which could be referenced. Because of
2200: this, the editor will suggest that the documents be loaded in ``skeleton''
2201: form. This form contains only the elements of the document explicitly
1.18 cvs 2202: mentioned in the <tt>EXPORT</tt> section of their structure schema and, for
1.1 cvs 2203: these elements, only the part of the contents specified in that section. This
2204: form has the advantage of being very compact, thus requiring very few
2205: resources from the editor. This is also the skeleton form which constitutes
1.18 cvs 2206: the expanded form of <a href="#inclusion">inclusions</a> with partial
2207: expansion.</p>
2208: <p>
2209: Skeleton elements must be declared explicitly in the <tt>EXPORT</tt> section
1.1 cvs 2210: of the structure schema that defines them. This section begins with the
1.18 cvs 2211: keyword <tt>EXPORT</tt> followed by a comma-separated list of the element
1.1 cvs 2212: types which must appear in the skeleton form and ending with a semicolon.
1.18 cvs 2213: These types must have been previously declared in the schema.</p>
2214: <p>
1.1 cvs 2215: For each skeleton element type, the part of the contents which is loaded by
2216: the editor, and therefore displayable, can be specified by putting the keyword
1.18 cvs 2217: <tt>WITH</tt> and the name of the contained element type to be loaded after
1.1 cvs 2218: the name of the skeleton element type. In this case only that named element,
2219: among all the elements contained in the exportable element type, will be
1.18 cvs 2220: loaded. If the <tt>WITH</tt> is absent, the entire contents of the skeleton
1.1 cvs 2221: element will be loaded by the editor. If instead, it is better that the
2222: skeleton form not load the contents of a particular element type, the keyword
1.18 cvs 2223: <tt>WITH</tt> must be followed by the word <tt>Nothing</tt>.</p>
2224: <pre> [ 'EXPORT' SkeletonSeq ]
1.1 cvs 2225:
2226: SkeletonSeq = SkelElem < ',' SkelElem > ';' .
2227: SkelElem = ElemID [ 'WITH' Contents ] .
1.18 cvs 2228: Contents = 'Nothing' / ElemID [ ExtStruct ] .</pre>
2229: <blockquote class="example">
2230: <p>
2231: <strong>Example:</strong></p>
2232: <p>
1.3 cvs 2233: Suppose that, in documents of the article class, the element types
2234: Article_title, Figure, Section, Paragraph, and Biblio should appear in the
2235: skeleton form in order to make it easier to create external references to them
2236: from other documents. When loading an article in its skeleton form, all of
2237: these element types will be loaded except for paragraphs, but only the article
1.18 cvs 2238: title will be loaded in its entirety. For figures, the caption will be
2239: loaded, while for sections, the title will be loaded, and for bibliographic
2240: entries, only the title that they contain will be loaded. Note that
1.3 cvs 2241: bibliographic elements are defined in another structure schema, RefBib. To
2242: produce this result, the following declarations should be placed in the
1.18 cvs 2243: Article structure schema:</p>
2244: <pre>EXPORT
1.1 cvs 2245: Article_title,
1.5 cvs 2246: Figure With Caption,
1.1 cvs 2247: Section With Section_title,
2248: Paragraph With Nothing,
1.18 cvs 2249: Biblio With Biblio_title(RefBib);</pre>
2250: </blockquote>
2251: </div>
1.1 cvs 2252:
1.18 cvs 2253: <div class="subsection">
1.1 cvs 2254:
1.18 cvs 2255: <h3><a name="sectc3214">Exceptions</a></h3>
2256: <p>
1.1 cvs 2257: The behavior of the Thot editor and the actions that it performs are
2258: determined by the structure schemas. These actions are applied to all
2259: document and object types in accordance with their generic structure. For
2260: certain object types, such as tables and graphics, these actions are not
2261: sufficient or are poorly adapted and some special actions must be added to or
2262: substituted for certain standard actions. These special actions are called
1.18 cvs 2263: <em>exceptions</em>.</p>
2264: <p>
1.1 cvs 2265: Exceptions only inhibit or modify certain standard actions, but they can be
1.18 cvs 2266: used freely in every structure schema.</p>
2267: <p>
1.1 cvs 2268: Each structure schema can contain a section defining exceptions. It begins
1.18 cvs 2269: with the keyword <tt>EXCEPT</tt> and is composed of a sequence of exception
1.1 cvs 2270: declarations, separated by semicolons. Each declaration of an exception
2271: begins with the name of an element type or attribute followed by a colon. This
2272: indicates the element type or attribute to which the following exceptions
1.18 cvs 2273: apply. When the given element type name is a <a href="#sectd3285">mark
2274: pair</a>, and only in this case, the type name can be preceded by the keyword
2275: <tt>First</tt> or <tt>Second</tt>, to indicate if the exceptions which follow
1.1 cvs 2276: are associated with the first mark of the pair or the second. In the absence
1.18 cvs 2277: of this keyword, the first mark is used.</p>
2278: <p>
2279: When placed in an <a href="#sectc322">extension schema</a>, the keyword
2280: <tt>EXTERN</tt> indicates that the type name which follows is found in the
1.1 cvs 2281: principal schema (the schema being extended by the extension schema). The
1.18 cvs 2282: exceptions are indicated by a name. They are separated by semicolons.</p>
2283: <pre> [ 'EXCEPT' ExceptSeq ]
1.1 cvs 2284:
2285: ExceptSeq = Except ';' < Except ';' > .
2286: Except = [ 'EXTERN' ] [ FirstSec ] ExcTypeOrAttr
2287: ':' ExcValSeq .
2288: ExcTypeOrAttr = ElemID / AttrID .
2289: ExcValSeq = ExcValue < ',' ExcValue > .
1.19 cvs 2290: ExcValue ='NoCut' / 'NoCreate' / 'NoHMove' /
2291: 'NoVMove' / 'NoHResize' / 'NoVResize' /
2292: 'NoMove' / 'NoResize' / 'MoveResize' /
2293: 'NewWidth' / 'NewHeight' / 'NewHPos' /
2294: 'NewVPos' / 'Invisible' /
1.28 ! cvs 2295: 'NoSelect' / 'NoSpellCheck' /
1.1 cvs 2296: 'Hidden' / 'ActiveRef' /
2297: 'ImportLine' / 'ImportParagraph' /
2298: 'NoPaginate' / 'ParagraphBreak' /
1.19 cvs 2299: 'PageBreak' / 'PageBreakAllowed' / 'PageBreakPlace' /
2300: 'PageBreakRepetition' / 'PageBreakRepBefore' /
1.9 cvs 2301: 'HighlightChildren' / 'ExtendedSelection' /
1.19 cvs 2302: 'ReturnCreateNL' / 'IsDraw' / 'IsTable' /
2303: 'IsRow' / 'IsColHead' / 'IsCell' /
2304: 'NewPercentWidth' / 'ColRef' / 'ColSpan' /
2305: 'RowSpan' / 'SaveDocument' / 'Shadow' .</pre>
1.18 cvs 2306: <p>
2307: The following are the available exceptions:</p>
2308: <dl>
2309: <dt><tt>NoCut</tt></dt>
2310: <dd>
2311: This exception can only be applied to element types. Elements of a type to
1.13 cvs 2312: which this exception is applied cannot be deleted by the editor.
1.18 cvs 2313: </dd>
2314: <dt><tt>NoCreate</tt></dt>
2315: <dd>
2316: This exception can only be applied to element types. Elements of a type to
1.2 cvs 2317: which this exception is applied cannot be created by ordinary commands for
2318: creating new elements. These elements are usually created by special actions
1.13 cvs 2319: associated with other exceptions.
1.18 cvs 2320: </dd>
2321: <dt><tt>NoHMove</tt></dt>
2322: <dd>
2323: This exception can only be applied to element types. Elements of a type to
2324: which this exception is applied cannot be moved horizontally with the mouse.
2325: Their children elements cannot be moved either.
2326: </dd>
2327: <dt><tt>NoVMove</tt></dt>
2328: <dd>
2329: This exception can only be applied to element types. Elements of a type to
2330: which this exception is applied cannot be moved vertically with the mouse.
2331: Their children elements cannot be moved either.
2332: </dd>
2333: <dt><tt>NoMove</tt></dt>
2334: <dd>
2335: This exception can only be applied to element types. Elements of a type to
1.2 cvs 2336: which this exception is applied cannot be moved in any direction with the
1.13 cvs 2337: mouse. Their children elements cannot be moved either.
1.18 cvs 2338: </dd>
2339: <dt><tt>NoHResize</tt></dt>
2340: <dd>
2341: This exception can only be applied to element types. Elements of a type to
2342: which this exception is applied cannot be resized horizontally with the mouse.
2343: Their children elements cannot be resized either.
2344: </dd>
2345: <dt><tt>NoVResize</tt></dt>
2346: <dd>
2347: This exception can only be applied to element types. Elements of a type to
2348: which this exception is applied cannot be resized vertically with the mouse.
2349: Their children elements cannot be resized either.
2350: </dd>
2351: <dt><tt>NoResize</tt></dt>
2352: <dd>
2353: This exception can only be applied to element types. Elements of a type to
1.2 cvs 2354: which this exception is applied cannot be resized in any direction with the
1.13 cvs 2355: mouse. Their children elements cannot be resized either.
1.18 cvs 2356: </dd>
2357: <dt><tt>MoveResize</tt></dt>
2358: <dd>
2359: This exception can only be applied to element types. Elements of a type to
2360: which this exception is applied can be moved and resized in any direction with
2361: the mouse, even if one of their ancestor element has an exception that
1.13 cvs 2362: prevents moving or resizing. Their children elements can also be resized or
2363: moved.
1.18 cvs 2364: </dd>
2365: <dt><tt>NewWidth</tt></dt>
2366: <dd>
2367: This exception can only be applied to numeric attributes. If the width of an
2368: element which has this attribute is modified with the mouse, the value of the
2369: new width will be assigned to the attribute.
2370: </dd>
2371: <dt><tt>NewHeight</tt></dt>
2372: <dd>
2373: This exception can only be applied to numeric attributes. If the height of an
2374: element which has this attribute is modified with the mouse, the value of the
2375: new height will be assigned to the attribute.
2376: </dd>
2377: <dt><tt>NewHPos</tt></dt>
2378: <dd>
2379: This exception can only be applied to numeric attributes. If the horizontal
2380: position of an element which has this attribute is modified with the mouse,
2381: the value of the new horizontal position will be assigned to the attribute.
2382: </dd>
2383: <dt><tt>NewVPos</tt></dt>
2384: <dd>
2385: This exception can only be applied to numeric attributes. If the vertical
2386: position of an element which has this attribute is modified with the mouse,
2387: the value of the new vertical position will be assigned to the attribute.
2388: </dd>
2389: <dt><tt>Invisible</tt></dt>
2390: <dd>
2391: This exception can only be applied to attributes, but can be applied to all
1.2 cvs 2392: attribute types. It indicates that the attribute must not be seen by the user
2393: and that its value must not be changed directly. This exception is usually
1.5 cvs 2394: used when another exception manipulates the value of an attribute.
1.18 cvs 2395: </dd>
1.19 cvs 2396: <dt><tt>NoSelect</tt></dt>
2397: <dd>
2398: This exception can only be applied to element types. Elements of a type to
2399: which this exception is applied cannot be selected directly with the mouse,
2400: but they can be selected by other methods provided by the editor.
2401: </dd>
2402: <dt>NoSpellCheck</dt>
2403: <dd>
2404: This exception can only be applied to element types. Elements of a type to
2405: which this exception is applied are not taken into account by the spell
2406: checker.
2407: </dd>
1.18 cvs 2408: <dt><tt>Hidden</tt></dt>
2409: <dd>
2410: This exception can only be applied to element types. It indicates that
1.2 cvs 2411: elements of this type, although present in the document's structure, must not
1.18 cvs 2412: be shown to the user of the editor. In particular, the creation menus must
2413: not propose this type and the selection message must not pick it.
2414: </dd>
2415: <dt><tt>ActiveRef</tt></dt>
2416: <dd>
2417: This exception can only be applied to attributes of the reference type. It
1.2 cvs 2418: indicates that when the user of the editor makes a double click on an element
2419: which possesses a reference attribute having this exception, the element
2420: designated by the reference attribute will be selected.
1.18 cvs 2421: </dd>
2422: <dt><tt>ImportLine</tt></dt>
2423: <dd>
2424: This exception can only be applied to element types. It indicates that
1.2 cvs 2425: elements of this type should receive the content of imported text files. An
2426: element is created for each line of the imported file. A structure schema
1.18 cvs 2427: cannot contain several exceptions <tt>ImportLine</tt> and, if it contains one,
2428: it should not contain any exception <tt>ImportParagraph</tt>.
2429: </dd>
2430: <dt><tt>ImportParagraph</tt></dt>
2431: <dd>
2432: This exception can only be applied to element types. It indicates that
1.2 cvs 2433: elements of this type should receive the content of imported text files. An
2434: element is created for each paragraph of the imported file. A paragraph is a
2435: sequence of lines without any empty line. A structure schema cannot contain
1.18 cvs 2436: several exceptions <tt>ImportParagraph</tt> and, if it contains one, it should
2437: not contain any exception <tt>ImportLine</tt>.
2438: </dd>
2439: <dt><tt>NoPaginate</tt></dt>
2440: <dd>
2441: This exception can only be applied to the root element, i.e. the name that
2442: appear after the keyword <tt>STRUCTURE</tt> at the beginning of the structure
1.2 cvs 2443: schema. It indicates that the editor should not allow the user to paginate
1.1 cvs 2444: documents of that type.
1.18 cvs 2445: </dd>
2446: <dt><tt>ParagraphBreak</tt></dt>
2447: <dd>
2448: This exception can only be applied to element types. When the caret is within
2449: an element of a type to which this exception is applied, it is that element
2450: that will be split when the user hits the Return key.
2451: </dd>
2452: <dt><tt>ReturnCreateNL</tt></dt>
2453: <dd>
2454: This exception can only be applied to element types. When the caret is within
2455: an element of a type to which this exception is applied, the Return key simply
2456: inserts a New line character (code \212) at the current position. The Return
2457: key does not create a new element; it does not split the current element
2458: either.
2459: </dd>
2460: <dt><tt>HighlightChildren</tt></dt>
2461: <dd>
2462: This exception can only be applied to element types. Elements of a type to
1.2 cvs 2463: which this exception is applied are not highlighted themselves when they are
2464: selected, but all their children are highlighted instead.
1.18 cvs 2465: </dd>
2466: <dt><tt>ExtendedSelection</tt></dt>
2467: <dd>
2468: This exception can only be applied to element types. The selection extension
2469: command (middle button of the mouse) only add the clicked element (if it has
2470: that exception) to the current selection, without selecting other elements
2471: between the current selection and the clicked element.
2472: </dd>
1.19 cvs 2473: <dt>IsDraw, IsTable, IsColHead, IsRow, IsCell</dt>
2474: <dd>
2475: These exceptions can only be applied to element types. Elements of a type to
2476: which these exceptions are applied are identified as Draws, Tables, Colheads,
2477: Rows or Cells and specific processing are applied to them.
2478: </dd>
2479: <dt>ColRef</dt>
2480: <dd>
2481: This exception can only be applied to attributes of the reference type. It
2482: indicates that this attribute refers to the column head (see exception
2483: IsColHead) which the element belongs to.
2484: </dd>
2485: <dt>ColSpan, RowSpan</dt>
2486: <dd>
2487: These exceptions can only be applied to numeric attributes of cells. They
2488: indicate that attribute values give how many columns or rows the element
1.20 cvs 2489: spans.
1.19 cvs 2490: </dd>
2491: <dt>Shadow</dt>
2492: <dd>
2493: This exception can only be applied to element types. Text of elements of a
2494: type to which this exception is applied are displayed and printed as a set of
2495: stars ('*').
2496: </dd>
1.18 cvs 2497: </dl>
2498: <blockquote class="example">
2499: <p>
2500: <strong>Example:</strong></p>
2501: <p>
1.3 cvs 2502: Consider a structure schema for object-style graphics which defines the
1.18 cvs 2503: Graphic_object element type with the associated Height and Weight numeric
2504: attributes. Suppose that we want documents of this class to have the
2505: following qualities:</p>
2506: <ul>
2507: <li>
2508: Whenever the width or height of an object is changed using the mouse, the new
2509: values are stored in the object's Width and Height attributes.
1.19 cvs 2510: </li>
1.18 cvs 2511: <li>
2512: The user should not be able to change the values of the Width and Height
1.5 cvs 2513: attributes via the Attributes menu of the Thot editor.
1.19 cvs 2514: </li>
1.18 cvs 2515: </ul>
2516: <p>
2517: The following exceptions will produce this effect.</p>
2518: <pre>STRUCT
1.1 cvs 2519: ...
1.5 cvs 2520: Graphics_object (ATTR Height = Integer; Width = Integer)
1.1 cvs 2521: = GRAPHICS with Height ?= 10, Width ?= 10;
2522: ...
2523: EXCEPT
2524: Height: NewHeight, Invisible;
1.18 cvs 2525: Width: NewWidth, Invisible;</pre>
2526: </blockquote>
2527: </div>
2528: </div>
1.1 cvs 2529:
1.18 cvs 2530: <div class="section">
1.1 cvs 2531:
1.18 cvs 2532: <h2><a name="sectb33">Some examples</a></h2>
2533: <p>
1.1 cvs 2534: In order to illustrate the principles of the document model and the syntax of
2535: the S language, this section presents two examples of structure schemas. One
1.18 cvs 2536: defines a class of documents, the other defines a class of objects.</p>
1.1 cvs 2537:
1.18 cvs 2538: <div class="subsection">
1.1 cvs 2539:
1.18 cvs 2540: <h3><a name="sectc331">A class of documents: articles</a></h3>
2541: <p>
1.1 cvs 2542: This example shows a possible structure for articles published in a journal.
1.18 cvs 2543: Text between braces is comments.</p>
2544: <pre>STRUCTURE Article; { This schema defines the Article class }
1.1 cvs 2545: DEFPRES ArticleP; { The default presentation schema is
2546: ArticleP }
2547: ATTR { Global attribute definitions }
2548: WordType = Definition, IndexWord, DocumentTitle;
2549: { A single global attribute is defined, with three values }
2550: STRUCT { Definition of the generic structure }
2551: Article = BEGIN { The Article class has an aggregate
2552: structure }
2553: Title = BEGIN { The title is an aggregate }
2554: French_title =
2555: Text WITH Language='Fran\347ais';
2556: English_title =
2557: Text WITH Language='English';
2558: END;
2559: Authors =
2560: LIST OF (Author
2561: (ATTR Author_type=principal,secondary)
2562: { The Author type has a local attribute }
2563: = BEGIN
2564: Author_name = Text;
2565: Info = Paragraphs ;
2566: { Paragraphs is defined later }
2567: Address = Text;
2568: END
2569: );
2570: Keywords = Text;
2571: { The journal's editor introduces the article
2572: with a short introduction, in French and
2573: in English }
2574: Introduction =
2575: BEGIN
2576: French_intr = Paragraphs WITH
2577: Language='Fran\347ais';
2578: English_intr = Paragraphs WITH
2579: Language='English';
2580: END;
2581: Body = Sections; { Sections are defined later }
2582: { Appendixes are only created on demand }
2583: ? Appendices =
2584: LIST OF (Appendix =
2585: BEGIN
2586: Appendix_Title = Text;
2587: Appendix_Contents = Paragraphs;
2588: END
2589: );
2590: END; { End of the Article aggregate }
2591:
2592: Sections = LIST [2..*] OF (
2593: Section = { At least 2 sections }
2594: BEGIN
2595: Section_title = Text;
2596: Section_contents =
2597: BEGIN
2598: Paragraphs;
2599: Sections; { Sections at a lower level }
2600: END;
2601: END
2602: );
2603:
2604: Paragraphs = LIST OF (Paragraph = CASE OF
2605: Enumeration =
2606: LIST [2..*] OF
2607: (Item = Paragraphs);
2608: Isolated_formula = Formula;
2609: LIST OF (UNIT);
2610: END
2611: );
2612:
2613: ASSOC { Associated elements definitions }
2614:
2615: Figure = BEGIN
1.5 cvs 2616: Figure_caption = Text;
1.1 cvs 2617: Illustration = NATURE;
2618: END;
2619:
2620: Biblio_citation = CASE OF
2621: Ref_Article =
2622: BEGIN
2623: Authors_Bib = Text;
2624: Article_Title = Text;
2625: Journal = Text;
2626: Page_Numbers = Text;
2627: Date = Text;
2628: END;
2629: Ref_Livre =
2630: BEGIN
2631: Authors_Bib; { Defined above }
2632: Book_Title = Text;
2633: Editor = Text;
2634: Date; { Defined above }
2635: END;
2636: END;
2637:
2638: Note = Paragraphs - (Ref_note);
2639:
2640: UNITS { Elements which can be used in objects }
2641:
2642: Ref_note = REFERENCE (Note);
2643: Ref_biblio = REFERENCE (Biblio_citation);
2644: Ref_figure = REFERENCE (Figure);
2645: Ref_formula = REFERENCE (Isolated_formula);
2646:
2647: EXPORT { Skeleton elements }
2648:
2649: Title,
1.5 cvs 2650: Figure with Figure_caption,
1.1 cvs 2651: Section With Section_title;
2652:
1.18 cvs 2653: END { End of the structure schema }</pre>
2654: <p>
1.1 cvs 2655: This schema is very complete since it defines both paragraphs and
2656: bibliographic citations. These element types could just as well be defined in
1.18 cvs 2657: other structure schemas, as is the case with the <tt>Formula</tt> class. All
1.1 cvs 2658: sorts of other elements can be inserted into an article, since a paragraph can
2659: contain any type of unit. Similarly, figures can be any class of document or
1.18 cvs 2660: object that the user chooses.</p>
2661: <p>
1.1 cvs 2662: Generally, an article doesn't contain appendices, but it is possible to add
2663: them on explicit request: this is the effect of the question mark before the
1.18 cvs 2664: word Appendices.</p>
2665: <p>
1.1 cvs 2666: The Figure, Biblio_citation and Note elements are associated elements. Thus,
1.18 cvs 2667: they are only used in <tt>REFERENCE</tt> statements.</p>
2668: <p>
1.1 cvs 2669: Various types of cross-references can be put in paragraphs. They can also be
2670: placed the objects which are part of the article, since the cross-references
1.18 cvs 2671: are defined as units (<tt>UNITS</tt>).</p>
2672: <p>
1.1 cvs 2673: There is a single restriction to prevent the creation of Ref_note elements
1.18 cvs 2674: within notes.</p>
2675: <p>
1.1 cvs 2676: It is worth noting that the S language permits the definition of recursive
2677: structures like sections: a section can contain other sections (which are thus
2678: at the next lower level of the document tree). Paragraphs are also recursive
2679: elements, since a paragraph can contain an enumeration in which each element
1.18 cvs 2680: (<tt>Item</tt>) is composed of paragraphs.</p>
2681: </div>
1.1 cvs 2682:
1.18 cvs 2683: <div class="subsection">
1.1 cvs 2684:
1.18 cvs 2685: <h3><a name="sectc332">A class of objects: mathematical formulas</a></h3>
2686: <p>
2687: The example below defines the <tt>Formula</tt> class which is used in Article
1.1 cvs 2688: documents. This class represents mathematical formulas with a rather simple
2689: structure, but sufficient to produce a correct rendition on the screen or
2690: printer. To support more elaborate operations (formal or numeric
2691: calculations), a finer structure should be defined. This class doesn't use any
1.18 cvs 2692: other class and doesn't define any associated elements or units.</p>
2693: <pre>STRUCTURE Formula;
1.1 cvs 2694: DEFPRES FormulaP;
2695:
2696: ATTR
2697: String_type = Function_name, Variable_name;
2698:
2699: STRUCT
2700: Formula = Expression;
2701: Expression = LIST OF (Construction);
2702: Construction = CASE OF
2703: TEXT; { Simple character string }
2704: Index = Expression;
2705: Exponent = Expression;
2706: Fraction =
2707: BEGIN
1.6 cvs 2708: Numerator = Expression;
1.1 cvs 2709: Denominator = Expression;
2710: END;
2711: Root =
2712: BEGIN
2713: ? Order = TEXT;
2714: Root_Contents = Expression;
2715: END;
2716: Integral =
2717: BEGIN
2718: Integration_Symbol = SYMBOL;
2719: Lower_Bound = Expression;
2720: Upper_Bound = Expression;
2721: END;
2722: Triple =
2723: BEGIN
2724: Princ_Expression = Expression;
2725: Lower_Expression = Expression;
2726: Upper_Expression = Expression;
2727: END;
2728: Column = LIST [2..*] OF
2729: (Element = Expression);
2730: Parentheses_Block =
2731: BEGIN
2732: Opening = SYMBOL;
2733: Contents = Expression;
2734: Closing = SYMBOL;
2735: END;
2736: END; { End of Choice Constructor }
1.18 cvs 2737: END { End of Structure Schema }</pre>
2738: <p>
1.1 cvs 2739: This schema defines a single global attribute which allows functions and
2740: variables to be distinguished. In the presentation schema, this attribute can
2741: be used to choose between roman (for functions) and italic characters (for
1.18 cvs 2742: variables).</p>
2743: <p>
1.1 cvs 2744: A formula's structure is that of a mathematical expression, which is itself a
2745: sequence of mathematical constructions. A mathematical construction can be
2746: either a simple character string, an index, an exponent, a fraction, a root,
2747: etc. Each of these mathematical constructions has a sensible structure which
2748: generally includes one or more expressions, thus making the formula class's
1.18 cvs 2749: structure definition recursive.</p>
2750: <p>
1.1 cvs 2751: In most cases, the roots which appear in the formulas are square roots and
2752: their order (2) is not specified. This is why the Order component is marked
2753: optional by a question mark. When explicitly requested, it is possible to add
1.18 cvs 2754: an order to a root, for example for cube roots (order = 3).</p>
2755: <p>
1.1 cvs 2756: An integral is formed by an integration symbol, chosen by the user (simple
2757: integral, double, curvilinear, etc.), and two bounds. A more fine-grained
2758: schema would add components for the integrand and the integration variable.
2759: Similarly, the Block_Parentheses construction leaves the choice of opening and
2760: closing symbols to the user. They can be brackets, braces, parentheses,
1.18 cvs 2761: etc.</p>
2762: </div>
2763: </div>
2764: <hr>
1.19 cvs 2765:
1.18 cvs 2766: </div>
1.1 cvs 2767:
1.18 cvs 2768: <div class="chapter">
1.1 cvs 2769:
1.18 cvs 2770: <h1><a name="sect4">The P Language</a></h1>
1.1 cvs 2771:
1.18 cvs 2772: <div class="section">
1.1 cvs 2773:
1.18 cvs 2774: <h2><a name="sectb41">Document presentation</a></h2>
2775: <p>
1.1 cvs 2776: Because of the model adopted for Thot, the presentation of documents is
2777: clearly separated from their structure and content. After having presented
2778: the logical structure of documents, we now detail the principles implemented
1.18 cvs 2779: for their presentation. The concept of <em>presentation</em> encompasses what
1.5 cvs 2780: is often called the page layout, the composition, or the document style. It
1.18 cvs 2781: is the set of operations which display the document on the screen or print it
2782: on paper. Like logical structure, document presentation is defined
2783: generically with the help of a language, called P.</p>
1.1 cvs 2784:
1.18 cvs 2785: <div class="subsection">
1.1 cvs 2786:
1.18 cvs 2787: <h3><a name="sectc411">Two levels of presentation</a></h3>
2788: <p>
1.1 cvs 2789: The link between structure and presentation is clear: the logical organization
2790: of a document is used to carry out its presentation, since the purpose of the
2791: presentation is to make evident the organization of the document. But the
2792: presentation is equally dependent on the device used to render the document.
2793: Certain presentation effects, notably changes of font or character set, cannot
2794: be performed on all printers or on all screens. This is why Thot uses a
2795: two-level approach, where the presentation is first described in abstract
2796: terms, without taking into account each particular device, and then the
1.18 cvs 2797: presentation is realized within the constraints of a given device.</p>
2798: <p>
1.1 cvs 2799: Thus, presentation is only described as a function of the structure of the
2800: documents and the image that would be produced on an idealized device. For
2801: this reason, presentation descriptions do not refer to any device
1.18 cvs 2802: characteristics: they describe <em>abstract presentations</em> which can be
2803: concretized on different devices.</p>
2804: <p>
2805: A presentation description also defines a <em>generic presentation</em>, since
1.1 cvs 2806: it describes the appearance of a class of documents or objects. This generic
2807: presentation must also be applied to document and object instances, each
2808: conforming to its generic logical structure, but with all the allowances that
2809: were called to mind above: missing elements, constructed elements with other
1.18 cvs 2810: logical structures, etc.</p>
2811: <p>
1.1 cvs 2812: In order to preserve the homogeneity between documents and objects,
2813: presentation is described with a single set of tools which support the layout
2814: of a large document as well as the composition of objects like a graphical
2815: figure or mathematical formula. This unity of presentation description tools
2816: contrasts with the traditional approach, which focuses more on documents than
2817: objects and thus is based on the usual typographic conventions, such as the
2818: placement of margins, indentations, vertical spaces, line lengths,
1.18 cvs 2819: justification, font changes, etc.</p>
2820: </div>
1.1 cvs 2821:
1.18 cvs 2822: <div class="subsection">
1.1 cvs 2823:
1.18 cvs 2824: <h3><a name="sectc412">Boxes</a></h3>
2825: <p>
1.1 cvs 2826: To assure the homogeneity of tools, all presentation in Thot, for documents as
2827: well as for the objects which they contain, is based on the notion of the
1.18 cvs 2828: <em>box</em>, such as was implemented in T<sub><big>E</big></sub>X.</p>
2829: <p>
1.1 cvs 2830: Corresponding to each element of the document is a box, which is the
2831: rectangle enclosing the element on the display device (screen or sheet of
1.18 cvs 2832: paper); the outline of this rectangle is not visible, except when a <a
2833: href="#sectc4230a"><tt>ShowBox</tt> rule</a> applies to the element. The sides
2834: of the box are parallel to the sides of the screen or the sheet of paper. By
2835: way of example, a box is associated with a character string, a line of text, a
2836: page, a paragraph, a title, a mathematical formula, or a table cell.</p>
2837: <p>
1.1 cvs 2838: Whatever element it corresponds to, each box possesses four sides and four
1.18 cvs 2839: axes, which we designate as follows (<a href="#boxes">see figure</a>):</p>
2840: <dl>
2841: <dt><tt>Top</tt></dt>
2842: <dd>
2843: the upper side,
2844: </dd>
2845: <dt><tt>Bottom</tt></dt>
2846: <dd>
2847: the lower side,
2848: </dd>
2849: <dt><tt>Left</tt></dt>
2850: <dd>
2851: the left side,
2852: </dd>
2853: <dt><tt>Right</tt></dt>
2854: <dd>
2855: the right side,
2856: </dd>
2857: <dt><tt>VMiddle</tt></dt>
2858: <dd>
2859: the vertical axis passing through the center of the box,
2860: </dd>
2861: <dt><tt>HMiddle</tt></dt>
2862: <dd>
2863: the horizontal axis passing through the center of the box,
2864: </dd>
2865: <dt><tt>VRef</tt></dt>
2866: <dd>
2867: the vertical reference axis,
2868: </dd>
2869: <dt><tt>HRef</tt></dt>
2870: <dd>
2871: the horizontal reference axis.
2872: </dd>
2873: </dl>
2874:
2875: <div class="figure">
2876: <hr>
1.19 cvs 2877:
1.18 cvs 2878: <pre> Left VRef VMiddle Right
1.1 cvs 2879: : :
2880: Top -----------------------------
2881: | : : |
2882: | : : |
2883: | : : |
2884: | : : |
2885: | : : |
2886: HMiddle ..|...........................|..
2887: | : : |
2888: | : : |
2889: HRef ..|...........................|..
2890: | : : |
2891: | : : |
2892: Bottom -----------------------------
1.18 cvs 2893: : :</pre>
1.19 cvs 2894: <p align="center">
1.18 cvs 2895: <em><a name="boxes">The sides and axes of boxes</a><em></em></em></p>
2896: <hr>
1.19 cvs 2897:
1.18 cvs 2898: </div>
2899: <p>
1.1 cvs 2900: The principal role of boxes is to set the extent and position of the images of
2901: the different elements of a document with respect to each other on the
2902: reproduction device. This is done by defining relations between the boxes of
2903: different elements which give relative extents and positions to these
1.18 cvs 2904: boxes.</p>
2905: <p>
2906: There are three types of boxes:</p>
2907: <ul>
2908: <li>
2909: boxes corresponding to structural elements of the document,
1.19 cvs 2910: </li>
1.18 cvs 2911: <li>
2912: presentation boxes,
1.19 cvs 2913: </li>
1.18 cvs 2914: <li>
2915: page layout boxes.
1.19 cvs 2916: </li>
1.18 cvs 2917: </ul>
2918: <p>
2919: <strong>Boxes corresponding to structural elements of the document</strong>
1.1 cvs 2920: are those which linked to each of the elements (base or structured) of the
2921: logical structure of the document. Such a box contains all the contents of
1.18 cvs 2922: the element to which it corresponds (there is an exception: see <a
2923: href="#sectc4220">rules <tt>VertOverflow</tt> and <tt>HorizOverflow</tt></a>).
2924: These boxes form a tree-like structure, identical to that of the structural
2925: elements to which they correspond. This tree expresses the inclusion
2926: relationships between the boxes: a box includes all the boxes of its subtree.
2927: On the other hand, there are no predefined rules for the relative positions of
2928: the included boxes. If they are at the same level, they can overlap, be
2929: contiguous, or be disjoint. The rules expressed in the generic presentation
2930: specify their relative positions.</p>
2931: <p>
2932: <strong>Presentation boxes</strong> represent elements which are not found in
1.1 cvs 2933: the logical structure of the document but which are added to meet the needs of
2934: presentation. These boxes are linked to the elements of the logical structure
2935: that are best suited to bringing them out. For example, they are used to add
2936: the character string ``Summary:'' before the summary in the presentation of a
2937: report or to represent the fraction bar in a formula, or also to make the
2938: title of a field in a form appear. These elements have no role in the logical
2939: structure of the document: the presence of a Summary element in the document
2940: does not require the creation of another structural object to hold the word
2941: ``Summary''. Similarly, if a Fraction element contains both a Numerator
2942: element and a Denominator element, the fraction bar has no purpose
2943: structurally. On the other hand, these elements of the presentation are
2944: important for the reader of the reproduced document or for the user of an
2945: editor. This is why they must appear in the document's image. It is the
2946: generic presentation which specifies the presentation boxes to add by
2947: indicating their content (a base element for which the value is specified) and
2948: the position that they must take in the tree of boxes. During editing, these
1.18 cvs 2949: boxes cannot be modified by the user.</p>
2950: <p>
2951: <strong>Page layout boxes</strong> are boxes created implicitly by the page
1.1 cvs 2952: layout rules. These rules indicate how the contents of a structured element
2953: must be broken into lines and pages. In contrast to presentation boxes, these
2954: line and page boxes do not depend on the logical structure of the document,
1.18 cvs 2955: but rather on the physical constraints of the output devices: character size,
2956: height and width of the window on the screen or of the sheet of paper.</p>
2957: </div>
1.1 cvs 2958:
1.18 cvs 2959: <div class="subsection">
1.1 cvs 2960:
1.18 cvs 2961: <h3><a name="sectc413">Views and visibility</a></h3>
2962: <p>
1.1 cvs 2963: One of the operations that one might wish to perform on a document is to view
2964: it is different ways. For this reason, it is possible to define several
1.18 cvs 2965: <em>views</em> for the same document, or better yet, for all documents of the
1.1 cvs 2966: same class. A view is not a different presentation of the document, but
2967: rather a filter which only allows the display of certain parts of the
2968: document. For example, it might be desirable to see only the titles of
2969: chapters and sections in order to be able to move rapidly through the
2970: document. Such a view could be called a ``table of contents''. It might also
2971: be desirable to see only the mathematical formulas of a document in order to
2972: avoid being distracted by the non-mathematical aspects of the document. A
1.18 cvs 2973: ``mathematics'' view could provide this service.</p>
2974: <p>
1.1 cvs 2975: Views, like presentation, are based on the generic logical structure. Each
2976: document class, and each generic presentation, can be provided with views
2977: which are particularly useful for that class or presentation. For each view,
1.18 cvs 2978: the <em>visibility</em> of elements is defined, indicated whether or not the
1.1 cvs 2979: elements must be presented to the user. The visibility is calculated as a
2980: function of the type of the elements or their hierarchical position in the
2981: structure of the document. Thus, for a table of contents, all the ``Chapter
2982: Title'' and ``Section Title'' elements are made visible. However, the
2983: hierarchical level could be used to make the section titles invisible below a
2984: certain threshold level. By varying this threshold, the granularity of the
2985: view can be varied. In the ``mathematics'' view, only Formula elements would
1.18 cvs 2986: be made visible, no matter what their hierarchical level.</p>
2987: <p>
1.1 cvs 2988: Because views are especially useful for producing a synthetic image of the
2989: document, it is necessary to adapt the presentation of the elements to the
2990: view in which they appear. For example, it is inappropriate to have a page
2991: break before every chapter title in the table of contents. Thus, generic
2992: presentations take into account the possible views and permit each element
1.18 cvs 2993: type's presentation to vary according the view in which its image appears.</p>
2994: <p>
2995: <a name="views">Views</a> are also used, when editing documents, to display
1.1 cvs 2996: the associated elements. So, in addition to the primary view of the document,
2997: there can be a ``notes'' view and a ``figures'' view which contain,
2998: respectively, the associated elements of the Note and Figure types. In this
2999: way, it is possible to see simultaneously the text which refers to these
3000: elements and the elements themselves, even if they will be separated when
1.18 cvs 3001: printed.</p>
3002: </div>
1.1 cvs 3003:
1.18 cvs 3004: <div class="subsection">
1.1 cvs 3005:
1.18 cvs 3006: <h3><a name="sectc414">Pages</a></h3>
3007: <p>
1.1 cvs 3008: Presentation schemas can be defined which display the document as a long
3009: scroll, without page breaks. This type of schema is particularly well-suited
3010: to the initial phase of work on a document, where jumps from page to page
3011: would hinder composing and reading the document on a screen. In this case,
3012: the associated elements (such as notes), which are normally displayed in the
3013: page footer, are presented in a separate window. But, once the document is
3014: written, it may be desirable to display the document on the screen in the same
3015: manner in which it will be printed. So, the presentation schema must define
1.18 cvs 3016: pages.</p>
3017: <p>
1.1 cvs 3018: The P language permits the specification of the dimensions of pages as well as
3019: their composition. It is possible to generate running titles, page numbers,
3020: zones at the bottom of the page for notes, etc. The editor follows this model
3021: and inserts page break marks in the document which are used during printing,
1.18 cvs 3022: insuring that the pages on paper are the same as on the screen.</p>
3023: <p>
1.1 cvs 3024: Once a document has been edited with a presentation schema defining pages, it
3025: contains page marks. But it is always possible to edit the document using a
3026: schema without pages. In this case, the page marks are simply ignored by the
3027: editor. They are considered again as soon as a schema with pages is used.
1.18 cvs 3028: Thus, the user is free to choose between schemas with and without pages.</p>
3029: <p>
1.1 cvs 3030: Thot treats the page break, rather than the page itself, as a box. This page
3031: break box contains all the elements of one page's footer, a rule marking the
3032: edge of this page, and all the elements of the next page's header. The
3033: elements of the header and footer can be running titles, page number,
3034: associated elements (notes, for example), etc. All these elements, as well as
3035: their content and graphical appearance, are defined by the generic
1.18 cvs 3036: presentation.</p>
3037: </div>
1.1 cvs 3038:
1.18 cvs 3039: <div class="subsection">
1.1 cvs 3040:
1.18 cvs 3041: <h3><a name="sectc415">Numbering</a></h3>
3042: <p>
1.1 cvs 3043: Many elements are numbered in documents: pages, chapters, sections, formulas,
3044: theorems, notes, figures, bibliographic references, exercises, examples,
3045: lemmas, etc. Because Thot has a notion of logical structure, all of these
3046: numbers (with the exception of pages) are redundant with information implicit
3047: in the logical structure of the document. Such numbers are simply a way to
3048: make the structure of the document more visible. So, they are part of the
3049: document's presentation and are calculated by the editor from the logical
3050: structure. The structure does not contain numbers as such; it only defines
3051: relative structural positions between elements, which serve as ordering
1.18 cvs 3052: relations on these elements.</p>
3053: <p>
1.1 cvs 3054: If the structure schema defines the body of a document as a sequence of at
1.18 cvs 3055: least two chapters:</p>
3056: <pre>Body = LIST [2..*] OF Chapter;</pre>
3057: <p>
3058: the sequence defined by the list constructor is ordered and each chapter can
3059: be assigned a number based on its rank in the Body list. Therefore, all
3060: elements contained in lists a the structure of a document can be numbered, but
3061: they are not the only ones. The tree structure induced by the aggregate,
3062: list, and choice constructors (excluding references) defines a total order on
3063: the elements of the document's primary structure. So, it is possible to
3064: define a numbering which uses this order, filtering elements according to
3065: their type so that only certain element types are taken into account in the
3066: numbering. In this way, it possible to number all the theorems and lemmas of
3067: a chapter in the same sequence of numbers, even when they are not part of the
3068: same list constructor and appear at different levels of the document's tree.
3069: By changing the filter, they can be numbered separately: one sequence of
3070: numbers for theorems, another for the lemmas.</p>
3071: <p>
1.1 cvs 3072: Associated elements pose a special problem, since they are not part of the
3073: document's primary structure, but are attached only by references, which
3074: violate the total order of the document. Then, these associated elements are
3075: frequently numbered, precisely because the number is an effective way to
3076: visualize the reference. In order to resolve this problem, Thot implicitly
3077: defines a list constructor for each type of associated element, gathering
3078: together (and ordering) these elements. Thus, the associated elements can be
1.18 cvs 3079: numbered by type.</p>
3080: <p>
1.1 cvs 3081: Since they are calculated from the document's logical structure and only for
3082: the needs of the presentation, numbers are presentation elements, described by
3083: presentation boxes, just like the fraction bar or the word ``Summary''.
3084: Nevertheless, numbers differ from these other boxes because their content
3085: varies from instance to instance, even though they are of the same type,
3086: whereas all fraction bars are horizontal lines and the same word ``Summary''
1.18 cvs 3087: appears at the head of every document's summary.</p>
3088: </div>
1.1 cvs 3089:
1.18 cvs 3090: <div class="subsection">
1.1 cvs 3091:
1.18 cvs 3092: <h3><a name="sectc416">Presentation parameters</a></h3>
3093: <p>
1.1 cvs 3094: The principal parameters which determine document presentation are the
1.18 cvs 3095: <em>positions</em> and <em>dimensions</em> of boxes, the <em>font</em>, the
3096: <em>style</em>, the <em>size</em>, the <em>underlining</em> and the
3097: <em>color</em> of their content. From these parameters, and some others of
1.1 cvs 3098: less importance, it is possible to represent the usual typographic parameters
3099: for the textual parts of the document. These same parameters can be used to
3100: describe the geometry of the non-textual elements, even though they are
1.18 cvs 3101: two-dimensional elements unlike the text, which is linear.</p>
3102: <p>
1.1 cvs 3103: As we have already seen, the positions of the boxes always respect the rule
3104: of enclosure: a box in the tree encloses all the boxes of the next lower level
3105: which are attached to it. The positional parameters permit the specification
3106: of the position of each box in relation to the enclosing box or to its sibling
3107: boxes (boxes directly attached to the same enclosing box in the tree of
1.18 cvs 3108: boxes).</p>
3109: <p>
1.1 cvs 3110: The presentation parameters also provide control over the dimensions of the
3111: boxes. The dimensions of a box can depend either on its content or on its
3112: context (its sibling boxes and the enclosing box). Each dimension (height or
1.18 cvs 3113: width) can be defined independently of the other.</p>
3114: <p>
1.1 cvs 3115: Because of the position and dimension parameters, it is possible to do the
3116: same things that are normally done in typography by changing margins, line
3117: lengths, and vertical or horizontal skips. This approach can also align or
1.18 cvs 3118: center elements and groups of elements.</p>
3119: <p>
1.1 cvs 3120: In contrast to the position and dimension parameters, the font, style, size,
3121: underlining, and color do not concern the box itself (the rectangle delimiting
3122: the element), but its content. These parameters indicate the typographic
3123: attributes which must be applied to the text contained in the box, and by
1.18 cvs 3124: extension, to all base elements.</p>
3125: <p>
1.1 cvs 3126: For text, the font parameter is used to change the family of characters
3127: (Times, Helvetica, Courier, etc.); the style is used to obtain italic or
3128: roman, bold or light characters; the size determines the point size of the
3129: characters; underlining defines the type and thickness of the lines drawn
1.18 cvs 3130: above, below, or through the characters.</p>
3131: <p>
1.1 cvs 3132: For graphics, the line style parameter can be either solid, dotted, or dashed;
3133: the line thickness parameter controls the width of the lines; the fill pattern
1.18 cvs 3134: parameter determines how closed geometric figures must be filled.</p>
3135: <p>
1.1 cvs 3136: While some of the parameters which determine the appearance of a box's
3137: contents make sense only for one content type (text or graphic), other
3138: parameters apply to all content types: these are the color parameters. These
1.18 cvs 3139: indicate the color of lines and the background color.</p>
3140: </div>
3141: </div>
1.1 cvs 3142:
1.18 cvs 3143: <div class="section">
1.1 cvs 3144:
1.18 cvs 3145: <h2><a name="sectb42">Presentation description language</a></h2>
3146: <p>
1.1 cvs 3147: A generic presentation defines the values of presentation parameters (or the
3148: way to calculate those values) for a generic structure, or more precisely, for
3149: all the element types and all the global and local attributes defined in that
3150: generic structure. This definition of the presentation parameters is made
3151: with the P language. A program written in this language, that is a generic
1.18 cvs 3152: presentation expressed in P, is call a <em>presentation schema</em>. This
3153: section describes the syntax and semantics of the language, using the same <a
3154: href="#sectc321">meta-language</a> as was used for the definition of the S
3155: language.</p>
3156: <p>
1.1 cvs 3157: Recall that it is possible to write many different presentation schemas for
3158: the same class of documents or objects. This allows users to choose for a
3159: document the graphical appearance which best suits their type of work or
1.18 cvs 3160: their personal taste.</p>
1.1 cvs 3161:
1.18 cvs 3162: <div class="subsection">
1.1 cvs 3163:
1.18 cvs 3164: <h3><a name="sectc421">The organization of a presentation schema</a></h3>
3165: <p>
3166: A presentation schema begins with the word <tt>PRESENTATION</tt> and ends with
3167: the word <tt>END</tt>. The word <tt>PRESENTATION</tt> is followed by the name
1.1 cvs 3168: of the generic structure to which the presentation will be applied. This name
1.18 cvs 3169: must be the same as that which follows the keyword <tt>STRUCTURE</tt> in the
3170: structure schema associated with the presentation schema.</p>
3171: <p>
1.1 cvs 3172: After this declaration of the name of the structure, the following sections
1.18 cvs 3173: appear (in order):</p>
3174: <ul>
3175: <li>
3176: Declarations of
3177: <ul>
3178: <li>
3179: all views,
1.19 cvs 3180: </li>
1.18 cvs 3181: <li>
3182: printed views,
1.19 cvs 3183: </li>
1.18 cvs 3184: <li>
3185: counters,
1.19 cvs 3186: </li>
1.18 cvs 3187: <li>
3188: presentation constants,
1.19 cvs 3189: </li>
1.18 cvs 3190: <li>
3191: variables,
1.19 cvs 3192: </li>
1.18 cvs 3193: </ul>
1.19 cvs 3194: </li>
1.18 cvs 3195: <li>
3196: default presentation rules,
1.19 cvs 3197: </li>
1.18 cvs 3198: <li>
3199: presentation box and page layout box definitions,
1.19 cvs 3200: </li>
1.18 cvs 3201: <li>
3202: presentation rules for structured elements,
1.19 cvs 3203: </li>
1.18 cvs 3204: <li>
3205: presentation rules for attributes,
1.19 cvs 3206: </li>
1.18 cvs 3207: <li>
3208: rules for transmitting values to attributes of included documents.
1.19 cvs 3209: </li>
1.18 cvs 3210: </ul>
3211: <p>
1.1 cvs 3212: Each of these sections is introduced by a keyword which is followed by a
1.18 cvs 3213: sequence of declarations. Every section is optional.</p>
3214: <pre> SchemaPres ='PRESENTATION' ElemID ';'
1.1 cvs 3215: [ 'VIEWS' ViewSeq ]
3216: [ 'PRINT' PrintViewSeq ]
3217: [ 'COUNTERS' CounterSeq ]
3218: [ 'CONST' ConstSeq ]
3219: [ 'VAR' VarSeq ]
3220: [ 'DEFAULT' ViewRuleSeq ]
3221: [ 'BOXES' BoxSeq ]
3222: [ 'RULES' PresentSeq ]
3223: [ 'ATTRIBUTES' PresAttrSeq ]
3224: [ 'TRANSMIT' TransmitSeq ]
3225: 'END' .
1.18 cvs 3226: ElemID = NAME .</pre>
3227: </div>
1.1 cvs 3228:
1.18 cvs 3229: <div class="subsection">
1.1 cvs 3230:
1.18 cvs 3231: <h3><a name="sectc422">Views</a></h3>
3232: <p>
1.1 cvs 3233: Each of the possible views must be declared in the presentation schema. As
1.18 cvs 3234: has <a href="#views">already been described</a>, the presentation rules for an
1.1 cvs 3235: element type can vary according to the view in which the element appears. The
3236: name of the view is used to designate the view to which the presentation rules
1.18 cvs 3237: apply (see the <a href="#inkeyword"><tt>IN</tt> instruction</a>). The
1.1 cvs 3238: definition of the view's contents are dispersed throughout the presentation
3239: rules attached to the different element types and attributes. The
1.18 cvs 3240: <tt>VIEWS</tt> section is simply a sequence of view names separated by commas
3241: and terminated by a semi-colon.</p>
3242: <p>
1.1 cvs 3243: One of the view names (and only one) can be followed by the keyword
1.18 cvs 3244: <tt>EXPORT</tt>. This keyword identifies the view which presents the members
3245: of the document class in <a href="#sectc3213">skeleton form</a>. The
3246: graphical appearance and the content of this view is defined just as with
3247: other views, but it is useless to specify presentation rules concerning this
3248: view for the elements which are not loaded in the skeleton form.</p>
3249: <p>
1.1 cvs 3250: It is not necessary to declare any views; in this case there is a single
3251: unnamed view. If many views are declared, the first view listed is considered
3252: the principal view. The principal view is the one to which all rules that are
1.18 cvs 3253: not preceded by an indication of a view will apply (see the <a
3254: href="#inkeyword">instruction <tt>IN</tt></a>).</p>
3255: <p>
1.1 cvs 3256: The principal view is the the one which the editor presents on the screen when
3257: the user asks to create or edit a document. Thus, it makes sense to put the
3258: most frequently used view at the head of the list. But if the structure
1.18 cvs 3259: schema contains <a href="#sectc3213">skeleton elements</a> and is loaded in
3260: its skeleton form, the view whose name is followed by the keyword
3261: <tt>EXPORT</tt> will be opened and no other views can be opened.</p>
3262: <pre> 'VIEWS' ViewSeq
1.1 cvs 3263: ViewSeq = ViewDeclaration
1.6 cvs 3264: < ',' ViewDeclaration > ';' .
1.1 cvs 3265: ViewDeclaration = ViewID [ 'EXPORT' ] .
1.18 cvs 3266: ViewID = NAME .</pre>
3267: <blockquote class="example">
3268: <p>
3269: <strong>Example:</strong></p>
3270: <p>
1.3 cvs 3271: When editing a report, it might be useful have views of the table of contents
1.18 cvs 3272: and of the mathematical formulas, in addition to the principal view which
3273: shows the document in its entirety. To achieve this, a presentation schema
3274: for the Report class would have the following <tt>VIEWS</tt> section:</p>
3275: <pre>VIEWS
3276: Full_text, Table_of_contents, Formulas;</pre>
3277: <p>
1.1 cvs 3278: The contents of these views are specified in the presentation rules of the
1.18 cvs 3279: schema.</p>
3280: </blockquote>
3281: </div>
1.1 cvs 3282:
1.18 cvs 3283: <div class="subsection">
1.1 cvs 3284:
1.18 cvs 3285: <h3><a name="sectc423">Print Views</a></h3>
3286: <p>
1.1 cvs 3287: When editing a document, each view is presented in a different window. In
1.18 cvs 3288: addition to the views specified by the <tt>VIEWS</tt> instruction, the user
1.1 cvs 3289: can display the associated elements with one window for each type of
1.18 cvs 3290: associated element.</p>
3291: <p>
1.1 cvs 3292: When printing a document, it is possible to print any number of views, chosen
3293: from among all the views which the editor can display (views in the strict
3294: sense or associated elements). Print views, as well as the order in which
1.18 cvs 3295: they must be printed, are indicated by the <tt>PRINT</tt> instruction. It
3296: appears after the <tt>VIEWS</tt> instruction and is formed of the keyword
3297: <tt>PRINT</tt> followed by the ordered list of print view names. The print
1.1 cvs 3298: view names are separated by commas and followed by a semi-colon. A print view
1.18 cvs 3299: name is either a view name declared in the <tt>VIEWS</tt> instruction or the
1.1 cvs 3300: name of an associated element type (with an ``s'' added to the end). The
1.18 cvs 3301: associated element must have been declared in the <tt>ASSOC</tt> section of
3302: the structure schema.</p>
3303: <pre> 'PRINT' PrintViewSeq
1.1 cvs 3304: PrintViewSeq = PrintView < ',' PrintView > ';' .
1.18 cvs 3305: PrintView = ViewID / ElemID .</pre>
3306: <p>
3307: If the <tt>PRINT</tt> instruction is absent, the printing program will print
3308: only the principal view (the first view specified by the <tt>VIEWS</tt>
3309: instruction or the single, unnamed view when there is no <tt>VIEWS</tt>
3310: instruction).</p>
3311: <blockquote class="example">
3312: <p>
3313: <strong>Example:</strong></p>
3314: <p>
1.3 cvs 3315: Consider a Report presentation using the view declarations from the preceding
3316: example. Suppose we want to print the full text and table of contents views,
3317: but not the Formulas view, which is only useful when editing. In addition,
3318: suppose that we also want to print the bibliographic citations, which are
1.18 cvs 3319: associated elements (of type <tt>Citation</tt>). A sensible printing order
1.3 cvs 3320: would be to print the full text then the bibliography and finally the table of
3321: contents. To obtain this result when printing, the presentation schema would
1.18 cvs 3322: say:</p>
3323: <pre>PRINT
3324: Full_text, Citations, Table_of_contents;</pre>
3325: </blockquote>
3326: </div>
3327:
3328: <div class="subsection">
3329:
3330: <h3><a name="sectc424">Counters</a></h3>
3331: <p>
3332: A presentation has a <em>counter</em> for each type of number in the
1.1 cvs 3333: presentation. All counters, and therefore all types of numbers, used in the
1.18 cvs 3334: schema must be declared after the <tt>COUNTERS</tt> keyword.</p>
3335: <p>
1.1 cvs 3336: Each counter declaration is composed of a name identifying the counter
3337: followed by a colon and the counting function to be applied to the counter.
1.18 cvs 3338: The counter declaration ends with a semi-colon.</p>
3339: <p>
1.1 cvs 3340: The counting function indicates how the counter values will be calculated.
1.16 cvs 3341: Three types of counting functions are available. The first type is used to
3342: count the elements of a list or aggregate: it assigns to the counter the rank
1.18 cvs 3343: of the element in the list or aggregate. More precisely, the function</p>
3344: <pre>RANK OF ElemID [ LevelAsc ] [ INIT AttrID ]
3345: [ 'REINIT' AttrID ]</pre>
3346: <p>
3347: indicates that when an element creates, by a creation rule (see the <a
3348: href="#sectc4232"><tt>Create</tt> instructions</a>), a presentation box
1.5 cvs 3349: containing the counter value, this value is the rank of the creating element,
1.18 cvs 3350: if it is of type <tt>ElemID</tt>, otherwise the rank of the first element of
3351: type <tt>ElemID</tt> which encloses the creating element in the logical
3352: structure of the document.</p>
3353: <p>
1.1 cvs 3354: The type name can be preceded by a star in the special case where the
1.18 cvs 3355: structure schema defines an element of whose <tt>ElemID</tt> is the same as
3356: that of an <a href="#sectd3284">inclusion</a> without expansion or with
3357: partial expansion. To resolve this ambiguity, the <tt>ElemID</tt> alone
3358: refers to the type defined in the structure schema while the <tt>ElemID</tt>
3359: preceded by a star refers to the included type.</p>
3360: <p>
3361: The type name <tt>ElemID</tt> can be followed by an integer. That number
1.1 cvs 3362: represents the relative level, among the ancestors of the creating element, of
1.18 cvs 3363: the element whose rank is asked. If that relative level <i>n</i> is unsigned,
3364: the <i>n</i><sup>th</sup> element of type <tt>ElemID</tt> encountered when
1.1 cvs 3365: travelling the logical structure from the root to the creating element is
1.16 cvs 3366: taken into account. If the relative level is negative, the logical structure
3367: is travelled in the other direction, from the creating element to the
1.18 cvs 3368: root.</p>
3369: <p>
3370: The function can end with the keyword <tt>INIT</tt> followed by the name of a
1.1 cvs 3371: numeric attribute (and only a numeric attribute). Then, the rank of the first
3372: element of the list or aggregate is considered to be the value of this
3373: attribute, rather than the default value of 1, and the rank of the other
3374: elements is shifted accordingly. The attribute which determines the initial
1.18 cvs 3375: value is searched on the element itself and on its ancestors.</p>
3376: <p>
3377: The function can end with the keyword <tt>REINIT</tt> followed by the name of
1.1 cvs 3378: a numeric attribute (and only a numeric attribute). Then, if an element to be
3379: counted has this attribute, the counter value for this element is the
3380: attribute value and the following elements are numbered starting from this
1.18 cvs 3381: value.</p>
3382: <p>
3383: When the <tt>RANK</tt> function is written</p>
3384: <pre>RANK OF Page [ ViewID ] [ INIT AttrID ]</pre>
3385: <p>
3386: (<tt>Page</tt>is a keyword of the P language), the counter takes as its value
1.5 cvs 3387: the number of the page on which the element which creates the presentation box
3388: containing the number appears. This is done as if the pages of the document
3389: form a list for each view. The counter only takes into account the pages of
3390: the relevant view, that is the view displaying the presentation box whose
1.18 cvs 3391: contents take the value of the number. However, if the keyword <tt>Page</tt>
1.5 cvs 3392: is followed by the name of a view (between parentheses), it is the pages of
3393: that view that are taken into account. As in the preceding form, the
1.18 cvs 3394: <tt>RANK</tt> function applied to pages can end with the <tt>INIT</tt> keyword
1.5 cvs 3395: followed by the name of a numeric attribute which sets the value of the first
3396: page's number. This attribute must be a local attribute of the document
1.18 cvs 3397: itself, and not of one of its components.</p>
3398: <p>
1.1 cvs 3399: The second counting function is used to count the occurrences of a certain
1.18 cvs 3400: element type in a specified context. The instruction</p>
3401: <pre>SET n ON Type1 ADD m ON Type2 [ INIT AttrID ]</pre>
3402: <p>
1.5 cvs 3403: says that when the document is traversed from beginning to end (in the order
1.18 cvs 3404: induced by the logical structure), the counter is assigned the value
3405: <tt>n</tt> each time an element of type <tt>Type1</tt> is encountered, no
3406: matter what the current value of the counter, and the value <tt>m</tt> is
3407: added to the current value of the counter each time an element of type
3408: <tt>Type2</tt> is encountered.</p>
3409: <p>
3410: As with the <tt>RANK</tt> function, the type names can be preceded by a star
3411: to resolve the ambiguity of included elements.</p>
3412: <p>
3413: If the function ends with the keyword <tt>INIT</tt> followed by the name of an
1.1 cvs 3414: attribute and if the document possesses this attribute, the value of this
1.18 cvs 3415: attribute is used in place of <tt>n</tt>. The attribute must be numeric. It
3416: is searched on the element itself and on its ancestors.</p>
3417: <p>
3418: This function can also be used with the <tt>Page</tt> keyword in the place of
3419: <tt>Type1</tt> or <tt>Type2</tt>. In the first case, the counter is
3420: reinitialized on each page with the value <tt>n</tt>, while in the second
3421: case, it is incremented by <tt>m</tt> on each page. As with the preceding
3422: counting function, the word <tt>Page</tt> can be followed by a name between
1.1 cvs 3423: parentheses. In this case, the name specifies a view whose pages are taken
1.18 cvs 3424: into account.</p>
3425: <p>
3426: The definition of a counter can contain several <tt>SET</tt> functions and
3427: several <tt>ADD</tt> functions, each with a different value. The total number
3428: of counting functions must not be greater than 6.</p>
3429: <p>
1.1 cvs 3430: The third counting function is used to count the elements of a certain type
1.16 cvs 3431: encountered when travelling from the creating element to the root of the
3432: logical structure. The creating element is included if it is of that type.
1.18 cvs 3433: That function is written</p>
3434: <pre>RLEVEL OF Type</pre>
3435: <p>
3436: where <tt>Type</tt> represents the type of the elements to be counted.</p>
3437: <p>
3438: The formal definition of counter declarations is:</p>
3439: <pre> 'COUNTERS' CounterSeq
1.1 cvs 3440: CounterSeq = Counter < Counter > .
3441: Counter = CounterID ':' CounterFunc ';' .
3442: CounterID = NAME .
3443: CounterFunc = 'RANK' 'OF' TypeOrPage [ SLevelAsc ]
1.16 cvs 3444: [ 'INIT' AttrID ] [ 'REINIT' AttrID ] /
1.1 cvs 3445: SetFunction < SetFunction >
1.16 cvs 3446: AddFunction < AddFunction >
3447: [ 'INIT' AttrID ] /
3448: 'RLEVEL' 'OF' ElemID .
1.1 cvs 3449: SLevelAsc = [ '-' ] LevelAsc .
3450: LevelAsc = NUMBER .
3451: SetFunction = 'SET' CounterValue 'ON' TypeOrPage .
3452: AddFunction = 'ADD' CounterValue 'ON' TypeOrPage .
3453: TypeOrPage = 'Page' [ '(' ViewID ')' ] /
1.16 cvs 3454: [ '*' ] ElemID .
1.18 cvs 3455: CounterValue = NUMBER .</pre>
3456: <blockquote class="example">
3457: <p>
3458: <strong>Example:</strong></p>
3459: <p>
1.3 cvs 3460: If the body of a chapter is defined as a sequence of sections in the structure
1.18 cvs 3461: schema:</p>
3462: <pre>Chapter_body = LIST OF (Section =
1.1 cvs 3463: BEGIN
3464: Section_Title = Text;
3465: Section_Body = Paragraphs;
3466: END
1.18 cvs 3467: );</pre>
3468: <p>
3469: the section counter is declared:</p>
3470: <pre>SectionCtr : RANK OF Section;</pre>
3471: <p>
3472: and the display of the section number before the section title is obtained by
3473: a <a href="#sectc4232"><tt>CreateBefore</tt> rule</a> attached the
3474: <tt>Section_Title</tt> type, which creates a presentation box whose content is
3475: the value of the <tt>SectionCtr</tt> counter (see the <a
3476: href="#sectc4231"><tt>Content</tt> instruction</a>).</p>
3477: <p>
1.1 cvs 3478: In order to number the formulas separately within each chapter, the formula
1.18 cvs 3479: counter is declared:</p>
3480: <pre>FormulaCtr : SET 0 ON Chapter ADD 1 ON Formula;</pre>
3481: <p>
1.4 cvs 3482: and the display of the formula number in the right margin, alongside each
1.18 cvs 3483: formula, is obtained by a <tt>CreateAfter</tt> instruction attached to the
3484: <tt>Formula</tt> type, which creates a presentation box whose content is the
3485: value of the <tt>FormulaCtr</tt> counter.</p>
3486: <p>
1.1 cvs 3487: To number the page chapter by chapter, with the first page of each chapter
1.18 cvs 3488: having the number 1, the counter definition would be</p>
3489: <pre>ChapterPageCtr : SET 0 ON Chapter ADD 1 ON Page;</pre>
3490: <p>
3491: If there is also a chapter counter</p>
3492: <pre>ChapterCtr : RANK OF Chapter;</pre>
3493: <p>
3494: the <a href="#sectc4231">content</a> of a presentation box created at the top
3495: of each page could be defined as:</p>
3496: <pre>Content : (VALUE(ChapterCtr, URoman) TEXT '-'
3497: VALUE(ChapterPageCtr, Arabic));</pre>
3498: <p>
1.5 cvs 3499: Thus, the presentation box contains the number of the chapter in upper-case
1.18 cvs 3500: roman numerals followed by a hyphen and the number of the page within the
3501: chapter in arabic numerals.</p>
3502: </blockquote>
3503: <blockquote class="example">
3504: <p>
3505: <strong>Example:</strong></p>
3506: <p>
1.3 cvs 3507: To count tables and figures together in a document of the chapter type, a
1.18 cvs 3508: counter could be defined using:</p>
3509: <pre>CommonCtr : SET 0 ON Chapter ADD 1 ON Table
3510: ADD 1 ON Figure;</pre>
3511: </blockquote>
3512: </div>
1.1 cvs 3513:
1.18 cvs 3514: <div class="subsection">
1.1 cvs 3515:
1.18 cvs 3516: <h3><a name="sectc425">Presentation constants</a></h3>
3517: <p>
1.1 cvs 3518: Presentation constants are used in the definition of the content of
1.18 cvs 3519: presentation boxes. This content is used in <a href="#sectc426">variable
3520: definitions</a> and in the <a href="#sectc4231"><tt>Content</tt> rule</a>. The
1.1 cvs 3521: only presentation constants which can be used are character strings,
1.2 cvs 3522: mathematical symbols, graphical elements, and pictures, that is to say, base
1.18 cvs 3523: elements.</p>
3524: <p>
1.1 cvs 3525: Constants can be defined directly in the variables or presentation boxes
1.18 cvs 3526: (<tt>Content</tt> rule) which use them. But it is only necessary them to
1.1 cvs 3527: declare once, in the constant declaration section, even though they are used
3528: in many variables or boxes. Thus, each declared constant has a name, which
3529: allows it to be designated whenever it is used, a type (one of the four base
3530: types) and a value (a character string or a single character for mathematical
1.18 cvs 3531: symbols and graphical elements).</p>
3532: <p>
3533: The constant declarations appear after the keyword <tt>CONST</tt>. Each
1.1 cvs 3534: declaration is composed of the name of the constant, an equals sign, a keyword
1.18 cvs 3535: representing its type (<tt>Text</tt>, <tt>Symbol</tt>, <tt>Graphics</tt> or
3536: <tt>Picture</tt>) and the string representing its value. A semi-colon
3537: terminates each declaration.</p>
3538: <p>
3539: In the case of a character string, the keyword <tt>Text</tt> can be followed
3540: by the name of an alphabet (for example, <tt>Greek</tt> or <tt>Latin</tt>) in
1.1 cvs 3541: which the constant's text should be expressed. If the alphabet name is
3542: absent, the Latin alphabet is used. When the alphabet name is present, only
3543: the first letter of the alphabet name is interpreted. Thus, the words
1.18 cvs 3544: <tt>Greek</tt> and <tt>Grec</tt> designate the same alphabet. In current
3545: versions of Thot, only the Greek and Latin alphabets are available.</p>
3546: <pre> 'CONST' ConstSeq
1.1 cvs 3547: ConstSeq = Const < Const > .
3548: Const = ConstID '=' ConstType ConstValue ';' .
3549: ConstID = NAME .
3550: ConstType ='Text' [ Alphabet ] / 'Symbol' /
3551: 'Graphics' / 'Picture' .
3552: ConstValue = STRING .
1.18 cvs 3553: Alphabet = NAME .</pre>
3554: <p>
1.5 cvs 3555: For character strings in the Latin alphabet (ISO Latin-1 character set),
1.1 cvs 3556: characters having codes higher than 127 (decimal) are represented by their
1.18 cvs 3557: code in octal.</p>
3558: <p>
1.1 cvs 3559: In the case of a symbol or graphical element, the value only contains a single
3560: character, between apostrophes, which indicates the form of the element which
3561: must be drawn in the box whose content is the constant. The symbol or
3562: graphical element takes the dimensions of the box, which are determined by the
1.18 cvs 3563: <tt>Height</tt> and <tt>Width</tt> rules. See <a href="#sectb72">table of
3564: codes</a> for the symbols and graphical elements.</p>
3565: <blockquote class="example">
3566: <p>
3567: <strong>Example:</strong></p>
3568: <p>
1.3 cvs 3569: The constants ``Summary:'' and fraction bar, which were described earlier, are
1.18 cvs 3570: declared:</p>
3571: <pre>CONST
1.1 cvs 3572: SummaryConst = Text 'Summary:';
1.18 cvs 3573: Bar = Graphics 'h';</pre>
3574: </blockquote>
3575: </div>
1.1 cvs 3576:
1.18 cvs 3577: <div class="subsection">
1.1 cvs 3578:
1.18 cvs 3579: <h3><a name="sectc426">Variables</a></h3>
3580: <p>
1.1 cvs 3581: Variables permit the definition of computed content for presentation boxes. A
1.18 cvs 3582: variable is associated with a presentation box by a <tt>Content</tt> rule; but
3583: before being used in a <tt>Content</tt> rule, a variable can be defined in the
3584: <tt>VAR</tt> section. It is also possible to define a variable at the time of
3585: its use in a <tt>Content</tt> rule, as can be done with a constant.</p>
3586: <p>
1.1 cvs 3587: A variable has a name and a value which is a character string resulting from
3588: the concatenation of the values of a sequence of functions. Each variable
3589: declaration is composed of the variable name followed by a colon and the
3590: sequence of functions which produces its value, separated by spaces. Each
1.18 cvs 3591: declaration is terminated by a semi-colon.</p>
3592: <pre> 'VAR' VarSeq
1.1 cvs 3593: VarSeq = Variable < Variable > .
3594: Variable = VarID ':' FunctionSeq ';' .
3595: VarID = NAME .
1.18 cvs 3596: FunctionSeq = Function < Function > .</pre>
3597: <p>
1.1 cvs 3598: Several functions are available. The first two return, in the form of a
1.18 cvs 3599: character string, the current date. <tt>DATE</tt> returns the date in
3600: English, while <tt>FDATE</tt> returns the date in french.</p>
3601: <p>
3602: Two other functions, <tt>DocName</tt> and <tt>DirName</tt>, return the
3603: document name and the directory where the document is stored.</p>
3604: <p>
3605: Function <tt>ElemName</tt> returns the type of the element which created the
3606: presentation box whose contents are the variable.</p>
3607: <p>
1.1 cvs 3608: Another function simply returns the value of a presentation constant. For any
1.18 cvs 3609: constant declared in the <tt>CONST</tt> section, it is sufficient to give the
1.1 cvs 3610: name of the constant. Otherwise, the type and value of the constant must be
1.18 cvs 3611: given, using the same form as in a <a href="#sectc425">constant
3612: declaration</a>. If the constant is not of type text, (types <tt>Symbol</tt>,
3613: <tt>Graphics</tt> or <tt>Picture</tt>), it must be alone in the variable
3614: definition; only constants of type <tt>Text</tt> can be mixed with other
3615: functions.</p>
3616: <p>
1.1 cvs 3617: It is also possible to obtain the value of an attribute, simply by mentioning
3618: the attribute's name. The value of this function is the value of the
3619: attribute for the element which created the presentation box whose contents
3620: are the variable. If the creating element does not have the indicated
3621: attribute, the value is an empty string. In the case of a numeric attribute,
3622: the attribute is translated into a decimal number in arabic numerals. If
1.18 cvs 3623: another form is desired, the <tt>VALUE</tt> function must be used.</p>
3624: <p>
1.1 cvs 3625: The last available function returns, as a character string, the value of a
3626: counter, an attribute or a page number. This value can be presented in
1.18 cvs 3627: different styles. The keyword <tt>VALUE</tt> is followed (between
1.1 cvs 3628: parentheses) by the name of the counter, the name of the attribute, or the
1.18 cvs 3629: keyword <tt>PageNumber</tt> and the desired style, the two parameters being
1.1 cvs 3630: separated by a comma. The style is a keyword which indicates whether the
1.18 cvs 3631: value should be presented in arabic numerals (<tt>Arabic</tt>), lower-case
3632: roman numerals (<tt>LRoman</tt>), or upper-case roman numerals
3633: (<tt>URoman</tt>), or by an upper-case letter (<tt>Uppercase</tt>) or
3634: lower-case letter (<tt>Lowercase</tt>).</p>
3635: <p>
3636: For a page counter, the keyword <tt>PageNumber</tt> can be followed, between
1.1 cvs 3637: parentheses, by the name of the view from which to obtain the page number. By
1.18 cvs 3638: default, the first view declared in the <tt>VIEWS</tt> section is used. The
1.1 cvs 3639: value obtained is the number of the page on which is found the element that is
1.18 cvs 3640: using the variable in a <tt>Content</tt> rule.</p>
3641: <p>
1.1 cvs 3642: For an ordinary counter, the name of the counter can be preceded by the
1.18 cvs 3643: keyword <tt>MaxRangeVal</tt> or <tt>MinRangeVal</tt>. These keywords mean
1.1 cvs 3644: that the value returned by the function is the maximum (minimum resp.) value
3645: taken by the counter in the whole document, not the value for the element
1.18 cvs 3646: concerned by the function.</p>
3647: <pre> Function = 'DATE' / 'FDATE' /
1.1 cvs 3648: 'DocName' / 'DirName' /
3649: 'ElemName' / 'AttributeName' /
3650: ConstID / ConstType ConstValue /
3651: AttrID /
3652: 'VALUE' '(' PageAttrCtr ','
3653: CounterStyle ')' .
1.6 cvs 3654: PageAttrCtr = 'PageNumber' [ '(' ViewID ')' ] /
1.1 cvs 3655: [ MinMax ] CounterID / AttrID .
3656: CounterStyle = 'Arabic' / 'LRoman' / 'URoman' /
3657: 'Uppercase' / 'Lowercase' .
1.18 cvs 3658: MinMax = 'MaxRangeVal' / 'MinRangeVal' .</pre>
3659: <blockquote class="example">
3660: <p>
3661: <strong>Example:</strong></p>
3662: <p>
3663: To make today's date appear at the top of the first page of a report, a <a
3664: href="#sectc4232"><tt>CREATE</tt> rule</a> associated with the Report_Title
1.3 cvs 3665: element type generates a presentation box whose content (specified by the
1.18 cvs 3666: <tt>Content</tt> rule of that presentation box) is the variable:</p>
3667: <pre>VAR
3668: Todays_date : TEXT 'Version of ' DATE;</pre>
3669: <p>
1.1 cvs 3670: To produce, before each section title, the chapter number (in upper-case roman
3671: numerals) followed by the section number (in arabic numerals), two counters
1.18 cvs 3672: must be defined:</p>
3673: <pre>COUNTERS
1.1 cvs 3674: ChapterCtr : RANK OF Chapter;
1.18 cvs 3675: SectionCtr : RANK OF Section;</pre>
3676: <p>
1.4 cvs 3677: and the Section_Title element must create a presentation box whose content is
1.18 cvs 3678: the variable</p>
3679: <pre>VAR
1.1 cvs 3680: SectionNum : VALUE (ChapterCtr, URoman) TEXT '-'
1.18 cvs 3681: VALUE (SectionCtr, Arabic);</pre>
3682: <p>
1.1 cvs 3683: In order to make the page number on which each section begins appear in the
3684: table of contents view next to the section title, each Section_Title element
3685: must create a presentation box, visible only in the table of contents view,
1.18 cvs 3686: whose content is the variable:</p>
3687: <pre>VAR
1.1 cvs 3688: TitlePageNume :
1.18 cvs 3689: VALUE (PageNumber(Full_text), Arabic);</pre>
3690: </blockquote>
3691: </div>
1.1 cvs 3692:
1.18 cvs 3693: <div class="subsection">
1.1 cvs 3694:
1.18 cvs 3695: <h3><a name="sectc427">Default presentation rules</a></h3>
3696: <p>
1.1 cvs 3697: In order to avoid having to specify, for each element type defined in the
3698: structure schema, values for every one of the numerous presentation
3699: parameters, the presentation schema allows the definition of a set of default
3700: presentation rules. These rules apply to all the boxes of the elements
3701: defined in the structure schema and to the presentation boxes and page layout
3702: boxes defined in the presentation schema. Only rules which differ from these
1.18 cvs 3703: default need to be specified in other sections of the presentation schema.</p>
3704: <p>
1.1 cvs 3705: For the primary view, the default rules can define every presentation
1.18 cvs 3706: parameter, but not the <a href="#presfunct">presentation functions</a> or the
3707: <a href="#sectc4223">linebreaking conditions</a> (the <tt>NoBreak1</tt>,
3708: <tt>NoBreak2</tt>, and <tt>Gather</tt> rules).</p>
3709: <p>
1.1 cvs 3710: In a presentation schema, the default presentation rules section is optional;
1.18 cvs 3711: in this case, the <tt>DEFAULT</tt> keyword is also absent and the following
3712: rules are considered to be the default rules:</p>
1.26 cvs 3713: <pre> Visibility: Enclosing =;
3714: VertRef: * . Left;
3715: HorizRef: Enclosed . HRef;
3716: Height: Enclosed . Height;
3717: Width: Enclosed . Width;
3718: VertPos: Top = Previous . Bottom;
3719: HorizPos: Left = Enclosing . Left;
3720: MarginTop: 0;
3721: MarginRight: 0;
3722: MarginBottom: 0;
3723: MarginLeft: 0;
3724: PaddingTop: 0;
3725: PaddingRight: 0;
3726: PaddingBottom: 0;
3727: PaddingLeft: 0;
3728: BorderTopWidth: 0;
3729: BorderRightWidth: 0;
3730: BorderBottomWidth: 0;
3731: BorderLeftWidth: 0;
3732: BorderTopColor: Foreground;
3733: BorderRightColor: Foreground;
3734: BorderBottomColor: Foreground;
3735: BorderLeftColor: Foreground;
3736: BorderTopStyle: None;
3737: BorderRightStyle: None;
3738: BorderBottomStyle: None;
3739: BorderLeftStyle: None;
3740: VertOverflow: No;
3741: HorizOverflow: No;
3742: Size: Enclosing =;
3743: Style: Enclosing =;
3744: Weight: Enclosing =;
3745: Font: Enclosing =;
3746: Underline: Enclosing =;
3747: Thickness: Enclosing =;
3748: Indent: Enclosing =;
3749: LineSpacing: Enclosing =;
3750: Adjust: Enclosing =;
3751: Justify: Enclosing =;
3752: Hyphenate: Enclosing =;
3753: PageBreak: Yes;
3754: LineBreak: Yes;
3755: InLine: Yes;
3756: Depth: 0;
3757: LineStyle: Enclosing =;
3758: LineWeight: Enclosing =;
3759: FillPattern: Enclosing =;
3760: Background: Enclosing =;
3761: Foreground: Enclosing =;</pre>
1.18 cvs 3762: <p>
1.1 cvs 3763: If other values are desired for the default rules, they must be defined
3764: explicitly in the default rules section. In fact, it is only necessary to
3765: define those default rules which differ from the ones above, since the rules
1.18 cvs 3766: above will be used whenever a rule is not explicitly named.</p>
3767: <p>
1.1 cvs 3768: Default rules for views other than the primary view can also be specified.
3769: Otherwise, the default rules for the primary views are applied to the other
1.18 cvs 3770: views.</p>
3771: <p>
3772: Default rules are expressed in the same way as <a href="#sectc4215">explicit
3773: rules for document elements</a>.</p>
3774: </div>
1.1 cvs 3775:
1.18 cvs 3776: <div class="subsection">
1.1 cvs 3777:
1.18 cvs 3778: <h3><a name="sectc428">Presentation and page layout boxes</a></h3>
3779: <p>
1.1 cvs 3780: The presentation process uses elements which are not part of the logical
3781: structure of the document, such as pages (which are the page layout boxes) or
3782: alternatively, rules, numbers, or words introducing certain parts of the
3783: document, such as ``Summary'', ``Appendices'', ``Bibliography'', etc. (which
1.18 cvs 3784: are presentation boxes).</p>
3785: <p>
3786: After the word <tt>BOXES</tt>, each presentation or page layout box is defined
1.1 cvs 3787: by its name and a sequence of presentation rules which indicate how they must
3788: be displayed. These rules are the same as those which define the boxes
3789: associated with element of the logical structure of the document, with a
1.18 cvs 3790: single exception, the <a href="#sectc4231"><tt>Content</tt> rule</a> which is
1.1 cvs 3791: used only to specify the content of presentation boxes. The content of boxes
3792: associated with elements of the document structure is defined in each document
3793: or object and thus is not specified in the presentation schema, which applies
1.18 cvs 3794: to all documents or objects of a class.</p>
3795: <p>
1.1 cvs 3796: Among the rules which define a presentation box, certain ones can refer to
3797: another presentation box (for example, in their positional rules). If the
3798: designated box is defined after the box which designates it, a
1.18 cvs 3799: <tt>FORWARD</tt> instruction followed by the name of the designated box must
3800: appear before the designation.</p>
3801: <pre> 'BOXES' BoxSeq
1.1 cvs 3802: BoxSeq = Box < Box > .
3803: Box ='FORWARD' BoxID ';' /
3804: BoxID ':' ViewRuleSeq .
1.18 cvs 3805: BoxID = NAME .</pre>
3806: </div>
1.1 cvs 3807:
1.18 cvs 3808: <div class="subsection">
1.1 cvs 3809:
1.18 cvs 3810: <h3><a name="sectc429">Presentation of structured elements</a></h3>
3811: <p>
3812: After the words <tt>RULES</tt>, the presentation schema gives the presentation
1.1 cvs 3813: rules that apply to the elements whose types are defined in the structure
1.18 cvs 3814: schema. Only those rules which differ from the <a
3815: href="#sectc427">default</a> must be specified in the <tt>RULES</tt>
3816: section.</p>
3817: <p>
1.1 cvs 3818: The rule definitions for each element type are composed of the name of the
3819: element type (as specified in the structure schema) followed by a colon and
1.18 cvs 3820: the set of rules specific to that type.</p>
3821: <p>
1.1 cvs 3822: The type name can be preceded by a star in the special case where the
1.18 cvs 3823: structure schema defines an <a href="#sectd3284">inclusion</a> without
1.1 cvs 3824: expansion (or with partial expansion) of a type with the same name as an
1.18 cvs 3825: element of defined in the structure schema.</p>
3826: <p>
3827: In the case where the element is a <a href="#sectd3285">mark pair</a>, but
3828: only in this case, the type name can be preceded by the keywords
3829: <tt>First</tt> or <tt>Second</tt>. These keywords indicate whether the rules
3830: that follow apply to the first or second mark of the pair.</p>
3831: <pre> 'RULES' PresentSeq
1.1 cvs 3832: PresentSeq = Present < Present > .
1.6 cvs 3833: Present = [ '*' ] [ FirstSec ] ElemID ':'
3834: ViewRuleSeq .
1.18 cvs 3835: FirstSec = 'First' / 'Second' .</pre>
3836: <p>
1.1 cvs 3837: A presentation schema can define presentation rules for base elements, which
3838: are defined implicitly in the structure schemas. In the English version of
3839: the presentation schema compiler, the base type names are the same as in the S
1.18 cvs 3840: language, but they are terminated by the <tt>_UNIT</tt> suffix:
3841: <tt>TEXT_UNIT</tt>, <tt>PICTURE_UNIT</tt>, <tt>SYMBOL_UNIT</tt>,
3842: <tt>GRAPHICS_UNIT</tt>. The base type names are written in upper-case
3843: letters.</p>
3844: </div>
3845:
3846: <div class="subsection">
3847:
3848: <h3><a name="sectc4210">Logical attribute presentation</a></h3>
3849: <p>
3850: After the keyword <tt>ATTRIBUTES</tt>, all attributes which are to have some
1.1 cvs 3851: effect on the presentation of the element to which they are attached must be
3852: mentioned, along with the corresponding presentation rules. This is true for
3853: both global attributes (which can be attached to all element types) and local
1.18 cvs 3854: attributes (which can only be attached to certain element types).</p>
3855: <p>
1.1 cvs 3856: Also mentioned in this section are attributes which imply an effect on
3857: elements in the subtree of the element to which they are attached. The
3858: presentation of these descendants can be modified as a function of the value
3859: of the attribute which they inherit, just as if it was attached to them
1.18 cvs 3860: directly.</p>
3861: <p>
1.1 cvs 3862: The specification for each attribute includes the attribute's name, followed
3863: by an optional value specification and, after a colon, a set of rules. The
1.18 cvs 3864: set of rules must contain at least one rule.</p>
3865: <p>
1.1 cvs 3866: When there is no value specification, the rules are applied to all elements
3867: which carry the attribute, no matter what their value. When the rules must
3868: only apply when the attribute has certain values, these values must be
1.18 cvs 3869: specified. Thus, the same attribute can appear in the <tt>ATTRIBUTES</tt>
1.1 cvs 3870: section several times, with each appearance having a different value
3871: specification. However, reference attributes never have a value specification
1.18 cvs 3872: and, as a result, can only appear once in the <tt>ATTRIBUTES</tt> section.</p>
3873: <p>
1.1 cvs 3874: To specify that the presentation rules apply to some of the descendants of the
3875: element having the attribute, the name of the affected element type is given,
3876: between parentheses, after the attribute name. This way, the presentation
3877: rules for the attribute will be applied to the element having the attribute,
3878: if it is of the given type, and to all of its descendants of the given type.
1.18 cvs 3879: In the case where this type is a <a href="#sectd3285">mark pair</a>, but only
3880: in this case, the type name can be preceded by the keywords <tt>First</tt> or
3881: <tt>Second</tt>. These keywords indicate whether the rules that follow apply
1.1 cvs 3882: to the first or second mark of the pair. If the rule must apply to several
3883: different element types, the specification must be repeated for each element
1.18 cvs 3884: type.</p>
3885: <p>
1.1 cvs 3886: The specification of values for which the presentation rules will be applied
1.18 cvs 3887: varies according to the type of the attribute:</p>
3888: <dl>
3889: <dt>numeric attribute</dt>
3890: <dd>
3891: If the rules are to apply for one value of the attribute, then the attribute
3892: name is followed by an equals sign and this value. If the rules are to apply
3893: for all values less than (or greater than) a threshold value, non-inclusive,
3894: the attribute name followed by a '<' sign (or a '>' sign, respectively) and
3895: the threshold value. If the rules must apply to a range of values, the
3896: attribute name is followed by the word '<tt>IN</tt>' and the two bounds of the
3897: range, enclosed in brackets and separated by two periods ('<tt>..</tt>'). In
3898: the case of ranges, the values of the bounds are included in the range.
3899: <p>
1.1 cvs 3900: The threshold value in the comparisons can be the value of an attribute
3901: attached to an ancestor element. In this case, the attribute name is given
1.18 cvs 3902: instead of a constant value.</p>
3903: <p>
1.1 cvs 3904: It is also possible to write rules which apply only when a comparison between
3905: two different attributes of the element's ancestors is true. In this case, the
3906: first attribute name is followed by a comparison keyword and the name of the
1.18 cvs 3907: second attribute. The comparison keywords are <tt>EQUAL</tt> (simple
3908: equality), <tt>LESS</tt> (non-inclusive less than), and <tt>GREATER</tt>
3909: (non-inclusive greater than).</p>
3910: </dd>
3911: <dt>text attribute</dt>
3912: <dd>
3913: If the rules are to apply for one value of the attribute, then the attribute
3914: name is followed by an equals sign and this value.
3915: </dd>
3916: <dt>reference attribute</dt>
3917: <dd>
3918: There is never a value specification; the rules apply no matter what element
3919: is designated by the attribute.
3920: </dd>
3921: <dt>enumerated attribute</dt>
3922: <dd>
3923: If the rules are to apply for one value of the attribute, then the attribute
3924: name is followed by an equals sign and this value.
3925: </dd>
3926: </dl>
3927: <p>
1.1 cvs 3928: The order in which the rules associated with a numeric attribute are defined
3929: is important. When multiple sets of rules can be applied, the first set
1.18 cvs 3930: declared is the one used.</p>
3931: <p>
1.1 cvs 3932: Rules for attributes have priority over both default rules and rules
3933: associated with element types. The attribute rules apply to the element to
3934: which the attribute is attached. It is the rules which apply to the
3935: surrounding elements (and especially to the descendants) which determine the
3936: effect of the attribute rules on the environment ( and especially on the
1.18 cvs 3937: terminal elements of the structure).</p>
3938: <pre> 'ATTRIBUTES' PresAttrSeq
1.1 cvs 3939: PresAttrSeq = PresAttr < PresAttr > .
3940: PresAttr = AttrID [ '(' [ FirstSec ] ElemID ')' ]
3941: [ AttrRelation ] ':' ViewRuleSeq .
3942: AttrID = NAME .
3943: AttrRelation ='=' AttrVal /
3944: '>' [ '-' ] MinValue /
3945: '<' [ '-' ] MaxValue /
3946: 'IN' '[' [ '-' ] LowerBound '..'
3947: [ '-' ] UpperBound ']' /
3948: 'GREATER' AttrID /
3949: 'EQUAL' AttrID /
3950: 'LESS' AttrID .
3951: AttrVal = [ '-' ] EqualNum / EqualText /
3952: AttrValue .
3953: MinValue = NUMBER .
3954: MaxValue = NUMBER .
3955: LowerBound = NUMBER .
3956: UpperBound = NUMBER.
3957: EqualNum = NUMBER .
3958: EqualText = STRING .
1.18 cvs 3959: AttrValue = NAME .</pre>
3960: <p>
1.1 cvs 3961: In presentation rules associated with a numeric attribute (and only in such
3962: rules), the attribute name can be used in place of a numeric value. In this
3963: case, the value of the attribute is used in the application of the rule. Thus,
3964: the attribute can represent a relation between the size of two boxes, the
3965: height and width of a box, the height of an area where page breaks are
3966: prohibited, the distance between two boxes, the position of the reference axis
3967: of a box, the interline spacing, the indentation of the first line, the
1.18 cvs 3968: visibility, the depth (z-order), or the character set.</p>
3969: <p>
1.1 cvs 3970: The presentation rules associated with reference attributes, it is possible to
3971: use the element designated by the attribute as a reference box in a positional
1.18 cvs 3972: or extent rule. This element is represented in the <a
3973: href="#sectc4218">position</a> or <a href="#sectc4219">extent</a> rule by the
3974: keyword <tt>Referred</tt>.</p>
3975: <blockquote class="example">
3976: <p>
3977: <strong>Example:</strong></p>
3978: <p>
1.3 cvs 3979: In all structure schemas, there is a global Language attribute defined as
1.18 cvs 3980: follows:</p>
3981: <pre>ATTR
3982: Language = TEXT;</pre>
3983: <p>
3984: The following rules would make French text be displayed in roman characters
3985: and English text be displayed in italics:</p>
3986: <pre>ATTRIBUTES
1.1 cvs 3987: Language = 'French' :
1.6 cvs 3988: Style : Roman;
1.1 cvs 3989: Language = 'English' :
1.18 cvs 3990: Style : Italics;</pre>
3991: <p>
1.4 cvs 3992: Using these rules, when the user puts the Language attribute with the value
3993: 'English' on the summary of a document, every character string (terminal
1.18 cvs 3994: elements) contained in the summary are displayed in italics. See the <a
3995: href="#sectd42252"><tt>Style</tt> rule</a>.</p>
3996: </blockquote>
3997: <blockquote class="example">
3998: <p>
3999: <strong>Example:</strong></p>
4000: <p>
1.3 cvs 4001: A numeric attribute representing the importance of the part of the document to
1.18 cvs 4002: which it is attached can be defined:</p>
4003: <pre>ATTR
4004: Importance = INTEGER;</pre>
4005: <p>
1.4 cvs 4006: In the presentation schema, the importance of an element is reflected in the
1.18 cvs 4007: choice of character size, using the following rules.</p>
4008: <pre>ATTRIBUTES
1.1 cvs 4009: Importance < 2 :
4010: Size : 1;
4011: Importance IN [2..4] :
4012: Size : Importance;
4013: Importance = 10 :
4014: Size : 5;
4015: Importance > 4 :
1.18 cvs 4016: Size : 4;</pre>
4017: <p>
1.4 cvs 4018: Thus, the character size corresponds to the value of the Importance attribute;
1.18 cvs 4019: its value is</p>
4020: <ul>
4021: <li>
4022: the value of the Importance attribute when the value is between 2 and 4
1.1 cvs 4023: (inclusive),
1.19 cvs 4024: </li>
1.18 cvs 4025: <li>
4026: 1, when the value of the Importance attribute is less than 2,
1.19 cvs 4027: </li>
1.18 cvs 4028: <li>
4029: 4, when the value of the Importance attribute is greater than 4,
1.19 cvs 4030: </li>
1.18 cvs 4031: <li>
4032: 5, when the value of the Importance attribute is 10.
1.19 cvs 4033: </li>
1.18 cvs 4034: </ul>
4035: <p>
1.4 cvs 4036: The last case (value 5) must be defined before the case which handles all
4037: Importance values greater than 4, because the two rules are not disjoint and
4038: the first one defined will have priority. Otherwise, when the Importance
1.18 cvs 4039: attribute has value 10, the font size will be 4.</p>
4040: </blockquote>
4041: <blockquote class="example">
4042: <p>
4043: <strong>Example:</strong></p>
4044: <p>
1.3 cvs 4045: Suppose the structure defines a list element which can have an attribute
1.18 cvs 4046: defining the type of list (numbered or not):</p>
4047: <pre>STRUCT
1.1 cvs 4048: list (ATTR list_type = enumeration, dash)
1.18 cvs 4049: = LIST OF (list_item = TEXT);</pre>
4050: <p>
1.4 cvs 4051: Then, the presentation schema could use the attribute placed on the list
4052: element to put either a dash or a number before the each element of the
1.18 cvs 4053: list:</p>
4054: <pre>ATTRIBUTES
1.1 cvs 4055: list_type (list_item) = enumeration :
4056: CreateBefore (NumberBox);
4057: list_type (list_item) = dash :
1.18 cvs 4058: CreateBefore (DashBox);</pre>
4059: </blockquote>
4060: <blockquote class="example">
4061: <p>
4062: <strong>Example:</strong></p>
4063: <p>
1.3 cvs 4064: Suppose that two attributes are defined in the structure schema. The first is
4065: a numeric global attribute called ``version''. The other is a local attribute
1.18 cvs 4066: defined on the root of the document called ``Document_version'':</p>
4067: <pre>STRUCTURE Document
1.1 cvs 4068: ATTR
4069: version = INTEGER;
4070: STRUCT
4071: Document (ATTR Document_version = INTEGER) =
4072: BEGIN
4073: SomeElement ;
4074: ...
4075: SomeOtherElement ;
4076: END ;
1.18 cvs 4077: ...</pre>
4078: <p>
4079: These attributes can be used in the presentation schema to place change bars
4080: in the margin next to elements whose version attribute has a value equal to
4081: the Document_version attribute of the root and to place a star in margin of
1.4 cvs 4082: elements whose version attribute is less than the value of the root's
1.18 cvs 4083: Document_version attribute:</p>
4084: <pre>ATTRIBUTES
1.1 cvs 4085: version EQUAL Document_version :
4086: CreateBefore (ChangeBarBox) ;
4087: version LESS Document_version :
1.18 cvs 4088: CreateBefore (StarBox) ;</pre>
4089: </blockquote>
4090: </div>
1.1 cvs 4091:
1.18 cvs 4092: <div class="subsection">
1.1 cvs 4093:
1.18 cvs 4094: <h3><a name="sectc4212">Value transmission rules</a></h3>
4095: <p>
1.1 cvs 4096: The last section of a presentation schema, which is optional, serves to
4097: defines the way in which a document transmits certain values to its
1.18 cvs 4098: sub-documents. A sub-document is an document <a
4099: href="#inclusion">included</a> without expansion or with partial expansion.
1.1 cvs 4100: The primary document can transmit to its sub-documents the values of certain
4101: counters or the textual content of certain of its elements, as a function of
1.18 cvs 4102: their type.</p>
4103: <p>
1.1 cvs 4104: The sub-documents receive these values in attributes which must be defined in
4105: their structure schema as local attributes of the root element. The types of
4106: these attributes must correspond to the type of the value which they receive:
4107: numeric attributes for receiving the value of a counter, textual attributes
1.18 cvs 4108: for receiving the content of an element.</p>
4109: <p>
1.1 cvs 4110: In the structure schema of the primary document, there appears at the end,
1.18 cvs 4111: after the <tt>TRANSMIT</tt> keyword, a sequence of transmission rules. Each
1.1 cvs 4112: rule begins with the name of the counter to transmit or of the element type
4113: whose textual content will be transmitted. This name is followed by the
1.18 cvs 4114: keyword <tt>To</tt> and the name of the attribute of the sub-document to which
1.1 cvs 4115: the value is transmitted. The sub-document class is indicated between
4116: parentheses after the name of the attribute. The transmission rule ends with
1.18 cvs 4117: a semicolon.</p>
4118: <pre> TransmitSeq = Transmit < Transmit > .
1.1 cvs 4119: Transmit = TypeOrCounter 'To' ExternAttr
4120: '(' ElemID ')' ';' .
4121: TypeOrCounter = CounterID / ElemID .
1.18 cvs 4122: ExternAttr = NAME .</pre>
4123: <blockquote class="example">
4124: <p>
4125: <strong>Example:</strong></p>
4126: <p>
4127: Consider a Book document class which includes instances of the Chapter
4128: document class. These classes might have the following schemas:</p>
4129: <pre>STRUCTURE Book
1.1 cvs 4130: STRUCT
4131: Book = BEGIN
4132: Title = Text;
4133: Body = LIST OF (Chapter INCLUDED);
4134: END;
4135: ...
4136:
4137: STRUCTURE Chapter
4138: STRUCT
4139: Chapter (ATTR FirstPageNum = Integer;
4140: ChapterNum = Integer;
4141: CurrentTitle = Text) =
1.6 cvs 4142: BEGIN
4143: ChapterTitle = Text;
4144: ...
4145: END;
1.18 cvs 4146: ...</pre>
4147: <p>
1.1 cvs 4148: Then the presentation schema for books could define chapter and page counters.
4149: The following transmission rules in the book presentation schema would
4150: transmit values for the three attributes defined at the root of each chapter
1.18 cvs 4151: sub-document.</p>
4152: <pre>PRESENTATION Book;
1.1 cvs 4153: VIEWS
4154: Full_text;
4155: COUNTERS
4156: ChapterCtr: Rank of Chapter;
4157: PageCtr: Rank of Page(Full_text);
4158: ...
4159: TRANSMIT
4160: PageCtr TO FirstPageNum(Chapter);
4161: ChapterCtr TO ChapterNum(Chapter);
4162: Title TO CurrentTitle(Chapter);
1.18 cvs 4163: END</pre>
4164: <p>
1.1 cvs 4165: Thus, each chapter included in a book can number its pages as a function of
4166: the number of pages preceding it in the book, can make the chapter's number
4167: appear before the number of each of its sections, or can place the title of
1.18 cvs 4168: the book at the top of each page.</p>
4169: </blockquote>
4170: </div>
1.1 cvs 4171:
1.18 cvs 4172: <div class="subsection">
1.1 cvs 4173:
1.18 cvs 4174: <h3><a name="sectc4213">Presentation rules</a></h3>
4175: <p>
1.1 cvs 4176: Whether defining the appearance of a presentation or page layout box, an
4177: element type, or an attribute value, the set of presentation rules that apply
1.18 cvs 4178: is always defined in the same way.</p>
4179: <p>
1.1 cvs 4180: Normally, a set of presentation rules is placed between the keywords
1.18 cvs 4181: <tt>BEGIN</tt> and <tt>END</tt>, the keyword <tt>END</tt> being followed by a
1.1 cvs 4182: semicolon. The first section of this block defines the rules that apply to
1.18 cvs 4183: the primary view, if the <a href="#sectc427">default rules</a> are not
1.1 cvs 4184: completely suitable. Next comes the rules which apply to specific other
4185: views, with a rule sequence for each view for which the default rules are not
4186: satisfactory. If the default rules are suitable for the non-primary views,
4187: there will not be any specific rules for these views. If there is only one
1.18 cvs 4188: rule which applies to all views then the keywords <tt>BEGIN</tt> and
4189: <tt>END</tt> need not appear.</p>
4190: <p>
1.1 cvs 4191: For each view, it is only necessary to specify those rules which differ from
4192: the default rules for the view, so that for certain views (or even all views),
1.18 cvs 4193: there may be no specific rules.</p>
4194: <p>
4195: The specific rules for a non-primary view are introduced by the <a
4196: name="inkeyword"><tt>IN</tt> keyword</a>, followed by the view name. The
4197: rules for that view follow, delimited by the keywords <tt>BEGIN</tt> and
4198: <tt>END</tt>, or without these two keywords when there is only one rule.</p>
4199: <p>
4200: <strong>Note:</strong> the view name which follows the <tt>IN</tt> keyword
1.1 cvs 4201: must not be the name of the primary view, since the rules for that view are
1.18 cvs 4202: found before the rules for the other views.</p>
4203: <p>
1.1 cvs 4204: Within each block concerning a view, other blocks can appear, delimited by the
1.18 cvs 4205: same keywords <tt>BEGIN</tt> and <tt>END</tt>. Each of these blocks gathers
1.1 cvs 4206: the presentation rules that apply, for a given view, only when a given
4207: condition is satisfied. Each block is preceded by a condition introduced by
1.18 cvs 4208: the <tt>IF</tt> keyword. If such a conditional block contains only one rule,
4209: the keywords <tt>BEGIN</tt> and <tt>END</tt> can be omitted.</p>
4210: <p>
1.1 cvs 4211: Although the syntax allows any presentation rule to appear in a conditional
1.18 cvs 4212: block, only <a href="#sectc4232">creation rules</a> are allowed after any
4213: condition; other rules are allowed only after conditions <tt>Within</tt> and
1.1 cvs 4214: ElemID. In addition, the following rules cannot be conditional:
1.18 cvs 4215: <tt>PageBreak, LineBreak, Inline, Gather</tt>.</p>
4216: <p>
1.1 cvs 4217: For a given view, the rules that apply without any condition must appear
4218: before the first conditional block. If some rules apply only when none of the
4219: specified condition holds, they are grouped in a block preceded by the keyword
1.18 cvs 4220: <tt>Otherwise</tt>, and that block must appear after the last conditionnal
4221: block concerning the same view.</p>
4222: <pre> ViewRuleSeq = 'BEGIN' < RulesAndCond > < ViewRules >
1.1 cvs 4223: 'END' ';' /
4224: ViewRules / CondRules / Rule .
4225: RulesAndCond = CondRules / Rule .
4226: ViewRules = 'IN' ViewID CondRuleSeq .
4227: CondRuleSeq = 'BEGIN' < RulesAndCond > 'END' ';' /
4228: CondRules / Rule .
4229: CondRules = CondRule < CondRule >
4230: [ 'Otherwise' RuleSeq ] .
4231: CondRule = 'IF' ConditionSeq RuleSeq .
4232: RulesSeq = 'BEGIN' Rule < Rule > 'END' ';' /
1.18 cvs 4233: Rule .</pre>
4234: <blockquote class="example">
4235: <p>
4236: <strong>Example:</strong></p>
4237: <p>
1.3 cvs 4238: The following rules for a report's title make the title visible in the primary
4239: view and invisible in the table of contents and in the formula views (see the
1.18 cvs 4240: <a href="#sectc4224"><tt>Visibility</tt> rule</a>).</p>
4241: <pre>Title : BEGIN
1.1 cvs 4242: Visibility : 1;
4243: ... {Other rules for the primary view}
4244: IN Table_of_contents
4245: Visibility : 0;
4246: IN Formulas
4247: Visibility : 0;
1.18 cvs 4248: END;</pre>
4249: </blockquote>
4250: </div>
1.1 cvs 4251:
1.18 cvs 4252: <div class="subsection">
1.1 cvs 4253:
1.18 cvs 4254: <h3><a name="sectc4214">Conditions applying to presentation rules</a></h3>
4255: <p>
1.1 cvs 4256: Many conditions can be applied to presentation rules. Conditions allow
4257: certain presentation rules to apply only in certain cases. These conditions
4258: can be based on the structural position of the element. They can be based on
4259: whether the element has references, and what type of references, whether the
4260: element has attributes, whether the element is empty or not. They can also be
1.18 cvs 4261: based on the value of a counter.</p>
4262: <p>
1.1 cvs 4263: It is possible to specify several conditions which must all be true for the
1.18 cvs 4264: rules to apply.</p>
4265: <p>
4266: A set of conditions is specified by the <tt>IF</tt> keyword. This keyword is
4267: followed by the sequence of conditions, separated by the <tt>AND</tt> keyword.
1.1 cvs 4268: Each condition is specified by a keyword which defines the condition type. In
4269: some cases, the keyword is followed by other data, which specify the condition
1.18 cvs 4270: more precisely.</p>
4271: <p>
1.1 cvs 4272: An elementary condition can be negative; it is then preceded by the
1.18 cvs 4273: <tt>NOT</tt> keyword.</p>
4274: <p>
1.1 cvs 4275: When the presentation rule(s) controlled by the condition apply to a reference
4276: element or a reference attribute, an elementary condition can also apply to
1.18 cvs 4277: element referred by this reference. The <tt>Target</tt> keyword is used for
1.1 cvs 4278: that purpose. It must appear before the keyword defining the condition
1.18 cvs 4279: type.</p>
4280: <pre> CondRule ='IF' ConditionSeq RuleSeq .
1.1 cvs 4281: ConditionSeq = Condition < 'AND' Condition > .
4282: Condition = [ 'NOT' ] [ 'Target' ] ConditionElem .
4283: ConditionElem ='First' / 'Last' /
4284: [ 'Immediately' ] 'Within' [ NumParent ]
4285: ElemID [ ExtStruct ] /
4286: ElemID /
4287: 'Referred' / 'FirstRef' / 'LastRef' /
4288: 'ExternalRef' / 'InternalRef' / 'CopyRef' /
4289: 'AnyAttributes' / 'FirstAttr' / 'LastAttr' /
4290: 'UserPage' / 'StartPage' / 'ComputedPage' /
4291: 'Empty' /
4292: '(' [ MinMax ] CounterName CounterCond ')' /
4293: CondPage '(' CounterID ')' .
4294: NumParent = [ GreaterLess ] NParent .
1.6 cvs 4295: GreaterLess ='>' / '<' .
1.1 cvs 4296: NParent = NUMBER.
1.6 cvs 4297: ExtStruct ='(' ElemID ')' .
1.1 cvs 4298: CounterCond ='<' MaxCtrVal / '>' MinCtrVal /
4299: '=' EqCtrVal /
4300: 'IN' '[' ['-'] MinCtrBound '.' '.'
4301: ['-'] MaxCtrBound ']' .
4302: PageCond ='Even' / 'Odd' / 'One' .
4303: MaxCtrVal = NUMBER .
4304: MinCtrVal = NUMBER .
4305: EqCtrVal = NUMBER .
4306: MaxCtrBound = NUMBER .
1.18 cvs 4307: MinCtrBound = NUMBER .</pre>
1.1 cvs 4308:
1.18 cvs 4309: <div class="subsubsection">
1.1 cvs 4310:
1.18 cvs 4311: <h4><a name="sectd42141">Conditions based on the logical position of the
4312: element</a></h4>
4313: <p>
1.1 cvs 4314: The condition can be on the position of the element in the document's logical
4315: structure tree. It is possible to test whether the element is the first
1.18 cvs 4316: (<tt>First</tt>) or last (<tt>Last</tt>) among its siblings or if it is not
4317: the first (<tt>NOT First</tt>) or not the last (<tt>NOT Last</tt>). These
4318: conditions can be associated only with <a href="#sectc4232">creation
4319: rules</a>.</p>
4320: <p>
1.1 cvs 4321: It is also possible to test if the element is contained in an element of a
1.18 cvs 4322: given type (<tt>Within</tt>) or if it is not (<tt>NOT Within</tt>). The type
4323: is indicated after the keyword <tt>Within</tt>. If that element type is
1.1 cvs 4324: defined in a structure schema which is not the one which corresponds to the
4325: presentation schema, the type name of this element must be followed, between
1.18 cvs 4326: parentheses, by the name of the structure schema which defines it.</p>
4327: <p>
4328: If the keyword <tt>Within</tt> is preceded by <tt>Immediately</tt>, the
4329: condition is satisfied only if the <em>parent</em> element has the type
4330: indicated. If the word <tt>Immediately</tt> is missing, the condition is
4331: satisfied if any <em>ancestor</em> has the type indicated.</p>
4332: <p>
4333: An integer <i>n</i> can appear between the keyword <tt>Within</tt> and the
1.1 cvs 4334: type. It specifies the number of ancestors of the indicated type that must be
4335: present for the condition to be satisfied. If the keyword
1.18 cvs 4336: <tt>Immediately</tt> is also present, the <i>n</i> immediate ancestors of the
4337: element must have the indicated type. The integer <i>n</i> must be positive
4338: or zero. It can be preceded by <tt><</tt> or <tt>></tt> to indicate a
1.1 cvs 4339: maximum or minimum number of ancestors. If these symbols are missing, the
1.18 cvs 4340: condition is satisfied only if it exists exactly <i>n</i> ancestors. When
4341: this number is missing, it is equivalent to > 0.</p>
4342: <p>
1.1 cvs 4343: If the condition applies to presentation rules associated with an attribute,
1.18 cvs 4344: in the <tt>ATTRIBUTES</tt> section of the presentation schema, the condition
1.1 cvs 4345: can be simply an element name. Presentation rules are then executed only if
1.18 cvs 4346: the attribute is attached to an element of that type. The keyword <tt>NOT</tt>
1.1 cvs 4347: before the element name indicates that the presentation rules must be executed
1.18 cvs 4348: only if the element is not of the type indicated.</p>
4349: </div>
1.1 cvs 4350:
1.18 cvs 4351: <div class="subsubsection">
1.1 cvs 4352:
1.18 cvs 4353: <h4><a name="sectd42142">Conditions on references</a></h4>
4354: <p>
1.1 cvs 4355: References may be taken into account in conditions, which can be based on the
4356: fact that the element, or one of its ancestors, is designated by a at least
1.18 cvs 4357: one reference (<tt>Referred</tt>) or by none (<tt>NOT Referred</tt>).</p>
4358: <p>
1.1 cvs 4359: If the element or attribute to which the condition is attached is a reference,
4360: the condition can be based on the fact that it acts as the first reference to
1.18 cvs 4361: the designated element (<tt>FirstRef</tt>), or as the last (<tt>LastRef</tt>),
1.1 cvs 4362: or as a reference to an element located in another document
1.18 cvs 4363: (<tt>ExternalRef</tt>) or in the same document (<tt>InternalRef</tt>).</p>
4364: <p>
4365: The condition can also be based on the fact that the element is an <a
4366: href="#inclusion">inclusion</a>. This is noted (<tt>CopyRef</tt>).</p>
4367: <p>
1.1 cvs 4368: Like all conditions, conditions on references can be inverted by the
1.18 cvs 4369: <tt>NOT</tt> keyword. These conditions can be associated only with <a
4370: href="#sectc4232">creation rules</a>.</p>
4371: </div>
1.1 cvs 4372:
1.18 cvs 4373: <div class="subsubsection">
1.1 cvs 4374:
1.18 cvs 4375: <h4><a name="sectd42143">Conditions on logical attributes</a></h4>
4376: <p>
1.1 cvs 4377: The condition can be based on the presence or absence of attributes associated
4378: with the element, no matter what the attributes or their values. The
1.18 cvs 4379: <tt>AnyAttributes</tt> keyword expresses this condition.</p>
4380: <p>
1.1 cvs 4381: If the condition appears in the presentation rules of an attribute, the
1.18 cvs 4382: <tt>FirstAttr</tt> and <tt>LastAttr</tt> keywords can be used to indicate that
1.1 cvs 4383: the rules must only be applied if this attribute is the first attribute for
4384: the element or if it is the last (respectively). These conditions can also be
1.18 cvs 4385: inverted by the <tt>NOT</tt> keyword. These conditions can be associated only
4386: with <a href="#sectc4232">creation rules</a>.</p>
4387: <p>
1.1 cvs 4388: It is also possible to apply certain presentation rules only when the element
4389: being processed or one of its ancestors has a certain attribute, perhaps with
1.18 cvs 4390: a certain value. This can be done in the <a
4391: href="#sectc4210"><tt>ATTRIBUTES</tt> section</a>.</p>
4392: </div>
1.1 cvs 4393:
1.18 cvs 4394: <div class="subsubsection">
1.1 cvs 4395:
1.18 cvs 4396: <h4><a name="sectd42144">Conditions on page breaks</a></h4>
4397: <p>
1.1 cvs 4398: The page break base type (and only this type) can use the following
1.18 cvs 4399: conditions: <tt>ComputedPage</tt>, <tt>StartPage</tt>, and <tt>UserPage</tt>.
4400: The <tt>ComputedPage</tt> condition indicates that the presentation rule(s)
1.1 cvs 4401: should apply if the page break was created automatically by Thot; the
1.18 cvs 4402: <tt>StartPage</tt> condition is true if the page break is generated before the
4403: element by the <tt>Page</tt> rule; and the <tt>UserPage</tt> condition applies
4404: if the page break was inserted by the user.</p>
4405: <p>
4406: These conditions can be associated only with <a href="#sectc4232">creation
4407: rules</a>.</p>
4408: </div>
1.1 cvs 4409:
1.18 cvs 4410: <div class="subsubsection">
1.1 cvs 4411:
1.18 cvs 4412: <h4><a name="sectd42145">Conditions on the element's content</a></h4>
4413: <p>
1.1 cvs 4414: The condition can be based on whether or not the element is empty. An element
4415: which has no children or whose leaves are all empty is considered to be empty
1.18 cvs 4416: itself. This condition is expressed by the <tt>Empty</tt> keyword, optionally
4417: preceded by the <tt>NOT</tt> keyword. This condition can be associated only
4418: with <a href="#sectc4232">creation rules</a>.</p>
4419: </div>
1.1 cvs 4420:
1.18 cvs 4421: <div class="subsubsection">
1.1 cvs 4422:
1.18 cvs 4423: <h4><a name="sectd42146">Conditions on counters</a></h4>
4424: <p>
1.1 cvs 4425: Presentation rules can apply when the counter's value is one, is even or odd,
4426: is equal, greater than or less than a given value or falls in a range of
4427: values. This is particularly useful for creating header and footer boxes.
1.18 cvs 4428: These conditions can be associated only with <a href="#sectc4232">creation
4429: rules</a>.</p>
4430: <p>
1.1 cvs 4431: To compare the value of a counter to a given value, a comparison is given
4432: between parentheses. The comparison is composed of the counter name followed
4433: by an equals, greater than, or less than sign and the value to which the
4434: counter will be compared. A test for whether or not a counter's value falls
4435: in a range also appears within parentheses. In this case, the counter name is
1.18 cvs 4436: followed by the <tt>IN</tt> keyword and the range definition within brackets.
4437: The <tt>Even</tt>, <tt>Odd</tt> and <tt>One</tt> are used to test a counter's
4438: value and are followed by the counter name between parentheses.</p>
4439: <p>
4440: The list of possible conditions on counters is:</p>
4441: <dl>
4442: <dt><tt>Even (Counter)</tt></dt>
4443: <dd>
4444: the box is created only if the counter has an even value.
4445: </dd>
4446: <dt><tt>Odd (Counter)</tt></dt>
4447: <dd>
4448: the box is created only if the counter has an odd value.
4449: </dd>
4450: <dt><tt>One (Counter)</tt></dt>
4451: <dd>
4452: the box is created only the counter's value is 1.
4453: </dd>
4454: <dt><tt>NOT One (Counter)</tt></dt>
4455: <dd>
4456: the box is created, unless the counter's value is 1.
4457: </dd>
4458: <dt><tt>(Counter < Value)</tt></dt>
4459: <dd>
4460: the box is created only if the counter's value is less than Value.
4461: </dd>
4462: <dt><tt>(Counter > Value)</tt></dt>
4463: <dd>
4464: the box is created only if the counter's value is greater than Value.
4465: </dd>
4466: <dt><tt>(Counter = Value)</tt></dt>
4467: <dd>
4468: the box is created only if the counter's value is equal to Value.
4469: </dd>
4470: <dt><tt>NOT (Counter = Value)</tt></dt>
4471: <dd>
4472: the is created only if the counter's value is different than Value.
4473: </dd>
4474: <dt><tt>(Counter IN [MinValue..MaxValue])</tt></dt>
4475: <dd>
4476: the box is created only if the counter's value falls in the range bounded by
4477: MinValue and MaxValue (inclusive).
4478: </dd>
4479: <dt><tt>NOT (Counter IN [MinValue..MaxValue])</tt></dt>
4480: <dd>
4481: the box is created only if the value of the counter does not fall in the range
4482: bounded by MinValue and MaxValue (inclusive).
4483: </dd>
4484: </dl>
4485: <p>
4486: <strong>Note:</strong> the <tt>NOT Even</tt> and <tt>NOT Odd</tt> conditions
4487: are syntactically correct but can be expressed more simply by <tt>Odd</tt> and
4488: <tt>Even</tt>, respectively.</p>
4489: </div>
4490: </div>
1.1 cvs 4491:
1.18 cvs 4492: <div class="subsection">
1.1 cvs 4493:
1.18 cvs 4494: <h3><a name="sectc4215">A presentation rule</a></h3>
4495: <p>
1.1 cvs 4496: A presentation rule defines either a presentation parameter or presentation
1.18 cvs 4497: function. The parameters are:</p>
4498: <ul>
4499: <li>
4500: the position of the vertical and horizontal reference axes of the box,
1.19 cvs 4501: </li>
1.18 cvs 4502: <li>
4503: the position of the box in relation to other boxes,
1.19 cvs 4504: </li>
1.18 cvs 4505: <li>
4506: the height or width of the box, with overflow exceptions,
1.19 cvs 4507: </li>
1.18 cvs 4508: <li>
1.26 cvs 4509: the margins, padding and borders of the box,
4510: </li>
4511: <li>
1.18 cvs 4512: the characteristics of the lines contained in the box: linespacing,
1.1 cvs 4513: indentation of the first line, justification, hyphenation,
1.19 cvs 4514: </li>
1.18 cvs 4515: <li>
4516: the conditions for breaking the box across pages,
1.19 cvs 4517: </li>
1.18 cvs 4518: <li>
4519: the characteristics of the characters contained in the box: size, font, style,
4520: underlining,
1.19 cvs 4521: </li>
1.18 cvs 4522: <li>
4523: the depth of the box among overlapping boxes (often called stacking order),
1.19 cvs 4524: </li>
1.18 cvs 4525: <li>
4526: the characteristics of graphic elements contained in the box: style and
1.1 cvs 4527: thickness of lines, fill pattern for closed objects,
1.19 cvs 4528: </li>
1.18 cvs 4529: <li>
4530: the colors in text, graphics, pictures, and symbols contained in the box are
4531: displayed or printed,
1.19 cvs 4532: </li>
1.18 cvs 4533: <li>
4534: for presentation boxes only, the contents of the box.
1.19 cvs 4535: </li>
1.18 cvs 4536: </ul>
4537: <p>
4538: The <a name="presfunct">presentation functions</a> are:</p>
4539: <ul>
4540: <li>
4541: the creation of a presentation box
1.19 cvs 4542: </li>
1.18 cvs 4543: <li>
4544: the line-breaking or page-breaking style,
1.19 cvs 4545: </li>
1.18 cvs 4546: <li>
4547: the copying of another box,
1.19 cvs 4548: </li>
1.18 cvs 4549: <li>
4550: the display of the box background and border,
1.19 cvs 4551: </li>
1.18 cvs 4552: <li>
4553: the display of a background picture and its aspect.
1.19 cvs 4554: </li>
1.18 cvs 4555: </ul>
4556: <p>
1.1 cvs 4557: For each box and each view, every presentation parameter is defined once and
1.18 cvs 4558: only once, either explicitly or by the <a href="#sectc427">default rules</a>.
4559: In contrast, presentation functions are not obligatory and can appear many
4560: times for the same element. for example an element can create many
4561: presentation boxes. Another element may not use any presentation
4562: functions.</p>
4563: <p>
1.1 cvs 4564: Each rule defining a presentation parameter begins with a keyword followed by
1.18 cvs 4565: a colon. The keyword indicates the parameter which is the subject of the
4566: rule. After the keyword and the colon, the remainder of the rule varies. All
4567: rules are terminated by a semicolon.</p>
4568: <pre> Rule = PresParam ';' / PresFunc ';' .
1.6 cvs 4569: PresParam ='VertRef' ':' PositionHoriz /
4570: 'HorizRef' ':' PositionVert /
4571: 'VertPos' ':' VPos /
4572: 'HorizPos' ':' HPos /
4573: 'Height' ':' Dimension /
4574: 'Width' ':' Dimension /
4575: 'VertOverflow' ':' Boolean /
1.1 cvs 4576: 'HorizOverflow' ':' Boolean /
1.26 cvs 4577: 'MarginTop' ':' MarginWidth /
4578: 'MarginRight' ':' MarginWidth /
4579: 'MarginBottom' ':' MarginWidth /
4580: 'MarginLeft' ':' MarginWidth /
4581: 'PaddingTop' ':' PaddingWidth /
4582: 'PaddingRight' ':' PaddingWidth /
4583: 'PaddingBottom' ':' PaddingWidth /
4584: 'PaddingLeft' ':' PaddingWidth /
4585: 'BorderTopWidth' ':' BorderWidth /
4586: 'BorderRightWidth' ':' BorderWidth /
4587: 'BorderBottomWidth' ':' BorderWidth /
4588: 'BorderLeftWidth' ':' BorderWidth /
4589: 'BorderTopColor' ':' BorderColor /
4590: 'BorderRightColor' ':' BorderColor /
4591: 'BorderBottomColor' ':' BorderColor /
4592: 'BorderLeftColor' ':' BorderColor /
4593: 'BorderTopStyle' ':' BorderStyle /
4594: 'BorderRightStyle' ':' BorderStyle /
4595: 'BorderBottomStyle' ':' BorderStyle /
4596: 'BorderLeftStyle' ':' BorderStyle .
1.6 cvs 4597: 'LineSpacing' ':' DistanceInherit /
4598: 'Indent' ':' DistanceInherit /
4599: 'Adjust' ':' AdjustInherit /
4600: 'Justify' ':' BoolInherit /
4601: 'Hyphenate' ':' BoolInherit /
4602: 'PageBreak' ':' Boolean /
4603: 'LineBreak' ':' Boolean /
4604: 'InLine' ':' Boolean /
4605: 'NoBreak1' ':' AbsDist /
4606: 'NoBreak2' ':' AbsDist /
4607: 'Gather' ':' Boolean /
4608: 'Visibility' ':' NumberInherit /
4609: 'Size' ':' SizeInherit /
4610: 'Font' ':' NameInherit /
4611: 'Style' ':' StyleInherit /
1.23 cvs 4612: 'Weight' ':' WeightInherit /
1.6 cvs 4613: 'Underline' ':' UnderLineInherit /
4614: 'Thickness' ':' ThicknessInherit /
4615: 'Depth' ':' NumberInherit /
4616: 'LineStyle' ':' LineStyleInherit /
4617: 'LineWeight' ':' DistanceInherit /
4618: 'FillPattern' ':' NameInherit /
4619: 'Background' ':' NameInherit /
1.13 cvs 4620: 'Foreground' ':' NameInherit /
1.6 cvs 4621: 'Content' ':' VarConst .
1.1 cvs 4622: PresFunc = Creation '(' BoxID ')' /
4623: 'Line' /
4624: 'NoLine' /
4625: 'Page' '(' BoxID ')' /
1.13 cvs 4626: 'Copy' '(' BoxTypeToCopy ')' /
4627: 'ShowBox' /
1.18 cvs 4628: 'BackgroundPicture' ':' FileName /
4629: 'PictureMode' ':' PictMode /</pre>
4630: </div>
4631:
4632: <div class="subsection">
4633:
4634: <h3><a name="sectc4216">Box axes</a></h3>
4635: <p>
4636: The position of the middle axes <tt>VMiddle</tt> and <tt>HMiddle</tt> in
1.1 cvs 4637: relation to their box is always calculated automatically as a function of the
4638: height and width of the box and is not specified by the presentation rules. In
4639: the presentation schema, these middle axes are used only to position their box
4640: with respect to another by specifying the distance between the middle axis and
1.18 cvs 4641: an axis or a side of another box (see the <a href="#sectc4218">relative
4642: position</a>).</p>
4643: <p>
1.1 cvs 4644: The reference axes of a box are also used to position their box in relation to
4645: another, but in contrast to the middle axes, the presentation schema must make
4646: their position explicit, either in relation to a side or the middle axis of
1.18 cvs 4647: the box itself, or in relation to an axis of an enclosed box.</p>
4648: <p>
1.1 cvs 4649: Only boxes of base elements have predefined reference axes. For character
4650: string boxes, the horizontal reference axis is the baseline of the characters
4651: (the line which passes immediately under the upper-case letters, ignoring the
4652: letter Q) and the vertical reference axis is at the left edge of the first
1.18 cvs 4653: character of the string.</p>
4654: <p>
4655: The positions of a box's reference axes are defined by the <tt>VertRef</tt>
4656: and <tt>HorizRef</tt> rules which specify the <a href="#distance">distance</a>
1.1 cvs 4657: between the reference axis and an axis or parallel side of the same box or of
1.18 cvs 4658: an enclosed box.</p>
4659: <pre> 'VertRef' ':' PositionHoriz
4660: 'HorizRef' ':' PositionVert</pre>
4661: <blockquote class="example">
4662: <p>
4663: <strong>Example:</strong></p>
4664: <p>
1.3 cvs 4665: If, in the structure schema for mathematical formulas, the fraction element is
1.18 cvs 4666: defined by</p>
4667: <pre>Fraction = BEGIN
1.1 cvs 4668: Numerator = Expression;
4669: Denominator = Expression;
1.18 cvs 4670: END;</pre>
4671: <p>
1.3 cvs 4672: then the horizontal reference axis of the fraction can be positioned on top of
1.18 cvs 4673: the denominator by the rule:</p>
4674: <pre>Fraction :
1.1 cvs 4675: BEGIN
4676: HorizRef : Enclosed Denominator . Top;
4677: ...
1.18 cvs 4678: END;</pre>
4679: <p>
4680: To put the horizontal reference axis of a column at its middle:</p>
4681: <pre>Column :
1.1 cvs 4682: BEGIN
4683: HorizRef : * . HMiddle;
4684: ...
1.18 cvs 4685: END;</pre>
4686: </blockquote>
4687: </div>
1.1 cvs 4688:
1.18 cvs 4689: <div class="subsection">
1.1 cvs 4690:
1.18 cvs 4691: <h3><a name="sectc4217">Distance units</a></h3>
4692: <p>
1.1 cvs 4693: Some distances and dimensions appear in many rules of a presentation schema,
1.18 cvs 4694: especially in position rules (<tt>VertPos, HorizPos</tt>), in extent rules for
4695: boxes (<tt>Height, Width</tt>), in rules defining lines (<tt>LineSpacing,
4696: Indent</tt>), in rules controlling pagination (<tt>NoBreak1, NoBreak2</tt>)
4697: and in rules specifying the thickness of strokes (<tt>LineWeight</tt>).</p>
4698: <p>
4699: In all these rules, the distance or extent can be expressed</p>
4700: <ul>
4701: <li>
4702: either in relative units, which depend on the size of the characters in the
4703: current font: height of the element's font or height of the letter 'x',
1.19 cvs 4704: </li>
1.18 cvs 4705: <li>
4706: or in absolute units: centimeter, millimeter, inch, typographer's point, pica
4707: or pixel.
1.19 cvs 4708: </li>
1.18 cvs 4709: </ul>
4710: <p>
1.5 cvs 4711: Units can be chosen freely. Thus, it is possible to use relative units in one
1.18 cvs 4712: rule, centimeters in the next rule, and typographer's points in another.</p>
4713: <p>
1.1 cvs 4714: Absolute units are used to set rigid rules for the appearance of documents. In
4715: contrast, relative units allow changes of scale. The editor lets the value of
4716: relative units be changed dynamically. Such changes affect every box using
4717: relative units simultaneously and in the same proportion. Changing the value
4718: of the relative units affects the size of the characters and graphical
1.18 cvs 4719: elements, and the size of the boxes and the distances between them.</p>
4720: <p>
4721: A <a name="distance">distance</a> or extent is specified by a number, which
1.1 cvs 4722: may be followed by one or more spaces and a units keyword. When there is no
4723: units keyword, the number specifies the number of relative units, where a
4724: relative unit is the height of a character in the current font (an em). When
4725: the number is followed by a units keyword, the keyword indicates the type of
1.18 cvs 4726: absolute units:</p>
4727: <ul>
4728: <li>
4729: <tt>em</tt>: height of the element's font,
1.19 cvs 4730: </li>
1.18 cvs 4731: <li>
4732: <tt>ex</tt>: height of the letter 'x',
1.19 cvs 4733: </li>
1.18 cvs 4734: <li>
4735: <tt>cm</tt>: centimeter,
1.19 cvs 4736: </li>
1.18 cvs 4737: <li>
4738: <tt>mm</tt>: millimeter,
1.19 cvs 4739: </li>
1.18 cvs 4740: <li>
4741: <tt>in</tt>: inch (1 in = 2.54 cm),
1.19 cvs 4742: </li>
1.18 cvs 4743: <li>
4744: <tt>pt</tt>: point (1 pt = 1/72 in),
1.19 cvs 4745: </li>
1.18 cvs 4746: <li>
4747: <tt>pc</tt>: pica (1 pc = 12 pt),
1.19 cvs 4748: </li>
1.18 cvs 4749: <li>
4750: <tt>px</tt>: pixel.
1.19 cvs 4751: </li>
1.18 cvs 4752: </ul>
4753: <p>
1.1 cvs 4754: Whatever the chosen unit, relative or absolute, the number is not necessarily
4755: an integer and may be expressed in fixed point notation (using the American
1.18 cvs 4756: convention of a period to express the decimal point).</p>
4757: <p>
1.1 cvs 4758: If the distance appears in a presentation rule for a numeric attribute, the
4759: number can be replaced by the name of an attribute. In this case, the value
4760: of the attribute is used. Obviously, the attribute name cannot be followed by
4761: a decimal point and a fractional part, but it can be followed a units keyword.
1.18 cvs 4762: However, the choice of units is limited to em, ex, pt and px.</p>
4763: <pre> Distance = [ Sign ] AbsDist .
1.1 cvs 4764: Sign ='+' / '-' .
4765: AbsDist = IntegerOrAttr [ '.' DecimalPart ]
4766: [ Unit ].
4767: IntegerOrAttr = IntegerPart / AttrID .
4768: IntegerPart = NUMBER .
4769: DecimalPart = NUMBER .
4770: Unit ='em' / 'ex' / 'cm' / 'mm' / 'in' / 'pt' /
1.18 cvs 4771: 'pc' / 'px' / '%' .</pre>
4772: <blockquote class="example">
4773: <p>
4774: <strong>Example:</strong></p>
4775: <p>
1.3 cvs 4776: The following rules specify that a box has a height of 10.5 centimeters and a
1.18 cvs 4777: width of 5.3 ems:</p>
4778: <pre>Height : 10.5 cm;
4779: Width : 5.3;</pre>
4780: </blockquote>
4781: </div>
1.1 cvs 4782:
1.18 cvs 4783: <div class="subsection">
1.1 cvs 4784:
1.18 cvs 4785: <h3><a name="sectc4218">Relative positions</a></h3>
4786: <p>
1.1 cvs 4787: The positioning of boxes uses the eight axes and sides, the sides generally
4788: being used to define the juxtapositioning (vertical or horizontal) of boxes,
4789: the middle axes being used to define centering, and the reference axes being
1.18 cvs 4790: used for alignment.</p>
4791: <p>
4792: Two rules allow a box to be placed relative to other boxes. The
4793: <tt>VertPos</tt> rule positions the box vertically. The <tt>HorizPos</tt>
4794: rule positions the box horizontally. It is possible that a box's position
4795: could be entirely determined by other boxes positioned relative to it. In this
4796: case, the position is implicit and the word <tt>nil</tt> can be used to
4797: specify that no position rule is needed. Otherwise, an explicit rule must be
4798: given by indicating the axis or side which defines the position of the box,
4799: followed by an equals sign and the distance between between this axis or side
4800: and a parallel axis or side of another box, called the reference box. The box
4801: for which the rule is written will be positioned relative to the reference
4802: box.</p>
4803: <pre> 'VertPos' ':' VPos
1.6 cvs 4804: 'HorizPos' ':' HPos
4805: HPos = 'nil' / VertAxis '=' HorizPosition
4806: [ 'UserSpecified' ].
4807: VPos = 'nil' / HorizAxis '=' VertPosition
4808: [ 'UserSpecified' ].
1.1 cvs 4809: VertAxis = 'Left' / 'VMiddle' / 'VRef' / 'Right' .
1.18 cvs 4810: HorizAxis = 'Top' / 'HMiddle' / 'HRef' / 'Bottom' .</pre>
4811: <p>
1.1 cvs 4812: The reference box is an adjacent box: enclosing, enclosed or adjacent. When a
4813: rule is associated with a reference type attribute (and only in this case), it
4814: can be a box of the element designated by the attribute. The reference box
1.18 cvs 4815: can be either a presentation box previously defined in the <tt>BOXES</tt>
1.1 cvs 4816: section of the schema and created by a creation function, or the box
1.18 cvs 4817: associated with a structured element.</p>
4818: <p>
1.1 cvs 4819: The structural position of the reference box (relative to the box for which
1.18 cvs 4820: the rule is being written) is indicated by a keyword: <tt>Enclosing</tt>,
4821: <tt>Enclosed</tt>, or, for sibling boxes, <tt>Previous</tt> or <tt>Next</tt>.
1.1 cvs 4822: The reference attributes, or presentation boxes created by a reference
1.18 cvs 4823: attribute, the <tt>Referred</tt> keyword may be used to designate the element
4824: which the reference points to. The keyword <tt>Creator</tt> can be used in
1.1 cvs 4825: rules for presentation boxes to designate the box of the element which created
1.18 cvs 4826: the presentation box. Finally, the <tt>Root</tt> keyword can be used to
4827: designate the root of the document.</p>
4828: <p>
4829: When the keyword is ambiguous, it is followed by the name of an element type
4830: or presentation box which resolves the ambiguity (the <tt>Creator</tt> and
4831: <tt>Root</tt> keywords are never ambiguous). If this name is not given, then
1.1 cvs 4832: the first box encountered is used as the reference box. It is also possible to
1.18 cvs 4833: use just the name of an element type or presentation box without an initial
4834: keyword. In this case, a sibling having that name will be used. If the name
4835: is preceded by the keyword <tt>NOT</tt>, then the reference box will be the
4836: first box whose type is not the named one.</p>
4837: <p>
4838: In place of the box or type name, the keywords <tt>AnyElem</tt>,
4839: <tt>AnyBox</tt> and <tt>ElemWithAttr</tt> can be used, representing
1.17 cvs 4840: respectively, any structured element box, any presentation box, and the box
4841: corresponding to any structured element having a particular attribute,
4842: whatever its value; the name of this attribute must follow the keyword
1.18 cvs 4843: <tt>ElemWithAttr</tt>.</p>
4844: <p>
1.17 cvs 4845: A type name may be preceded by a star in order to resolve the ambiguity in the
1.18 cvs 4846: special case where the structure schema defines an <a
4847: href="#sectd3284">inclusion</a> without expansion (or with partial expansion)
4848: of the same type as an element of the scheme. For mark pairs (and only for <a
4849: href="#sectd3285">mark pairs</a>) the type name <em>must</em> be preceded by
4850: the <tt>First</tt> or <tt>Second</tt> keyword, which indicates which of the
4851: two marks of the pair should be used as the reference box.</p>
4852: <p>
4853: The star character ('<tt>*</tt>') used alone designates the box to which the
1.1 cvs 4854: rule applies (in this case, it is obviously useless to specify the type of the
1.18 cvs 4855: reference box).</p>
4856: <p>
4857: The keywords <tt>Enclosing</tt> and <tt>Enclosed</tt> can be used no matter
1.1 cvs 4858: what constructor defines the type to which the rule applies. When applied to
1.18 cvs 4859: the element which represents the entire document, <tt>Enclosing</tt>
1.1 cvs 4860: designates the window or page in which the document's image is displayed for
4861: the view to which the rule applies. A box or type name without a keyword is
4862: used for aggregate elements and designates another element of the same
4863: aggregate. It can also be used to designate a presentation or page layout
1.18 cvs 4864: box. The keywords <tt>Previous</tt> and <tt>Next</tt> are primarily used to
1.1 cvs 4865: denote list elements, but can also be used to denote elements of an
1.18 cvs 4866: aggregate.</p>
4867: <p>
1.1 cvs 4868: In the position rule, the structural position relative to the reference box is
4869: followed, after a period, by the name of an axis or side. The rule specifies
4870: its node's position as being some distance from this axis or side of the
4871: reference box. If this distance is zero, then the distance does not appear in
4872: the rule. Otherwise, it does appear as a positive or negative number (the
4873: sign is required for negative numbers). The sign takes into account the
4874: orientation of the coordinate axes: for top to bottom for the vertical axis
4875: and from left to right for the horizontal axis. Thus, a negative distance in
4876: a vertical position indicates that the side or axis specified in the rule is
1.18 cvs 4877: above the side or axis of the reference box.</p>
4878: <p>
4879: The distance can be followed by the <tt>UserSpecified</tt> keyword (even if
4880: the distance is nil and does not appear, the <tt>UserSpecified</tt> keyword
1.1 cvs 4881: can be used). It indicates that when the element to which the rule applies is
4882: being created, the editor will ask the user to specify the distance himself,
4883: using the mouse. In this case, the distance specified in the rule is a
4884: default distance which is suggested to the user but can be modified. The
1.18 cvs 4885: <tt>UserSpecified</tt> keyword can be used either in the vertical position
4886: rule, the horizontal position rule, or both.</p>
4887: <pre> VertPosition = Reference '.' HorizAxis [ Distance ] .
1.1 cvs 4888: HorizPosition = Reference '.' VertAxis [ Distance ] .
4889: Reference ='Enclosing' [ BoxTypeNot ] /
4890: 'Enclosed' [ BoxTypeNot ] /
4891: 'Previous' [ BoxTypeNot ] /
4892: 'Next' [ BoxTypeNot ] /
4893: 'Referred' [ BoxTypeNot ] /
4894: 'Creator' /
4895: 'Root' /
4896: '*' /
4897: BoxOrType .
4898: BoxOrType = BoxID /
4899: [ '*' ] [ FirstSec ] ElemID /
1.17 cvs 4900: 'AnyElem' / 'AnyBox' /
4901: 'ElemWithAttr' AttrID .
1.18 cvs 4902: BoxTypeNot = [ 'NOT' ] BoxOrType .</pre>
4903: <blockquote class="example">
4904: <p>
4905: <strong>Example:</strong></p>
4906: <p>
4907: If a <a name="expos1">report</a> is defined by the following structure
4908: schema:</p>
4909: <pre>Report = BEGIN
1.6 cvs 4910: Title = Text;
4911: Summary = Text;
4912: Keywords = Text;
4913: ...
1.18 cvs 4914: END;</pre>
4915: <p>
4916: then the presentation schema could contain the rules:</p>
4917: <pre>Report : BEGIN
1.6 cvs 4918: VertPos : Top = Enclosing . Top;
4919: HorizPos : Left = Enclosing . Left;
4920: ...
1.18 cvs 4921: END;</pre>
4922: <p>
4923: These rules place the <a name="reportexample">report</a> in the upper left
4924: corner of the enclosing box, which is the window in which the document is
4925: being edited.</p>
4926: <pre>Title : BEGIN
1.6 cvs 4927: VertPos : Top = Enclosing . Top + 1;
4928: HorizPos : VMiddle = Enclosing . VMiddle;
4929: ...
1.18 cvs 4930: END;</pre>
4931: <p>
1.3 cvs 4932: The top of the title is one line (a line has the height of the characters of
4933: the title) from the top of the report, which is also the top of the editing
1.18 cvs 4934: window. The title is centered horizontally in the window (see <a
4935: href="#posdim">figure</a>).</p>
4936: <pre>Summary : BEGIN
1.1 cvs 4937: VertPos : Top = Title . Bottom + 1.5;
4938: HorizPos : Left = Enclosing . Left + 2 cm;
4939: ...
1.18 cvs 4940: END;</pre>
4941: <p>
4942: The top of the summary is place a line and a half below the bottom of the
4943: title and is shifted two centimeters from the side of the window.</p>
4944: </blockquote>
4945: <blockquote class="example">
4946: <p>
4947: <strong>Example:</strong></p>
4948: <p>
4949: Suppose there is a <a name="expos2">Design</a> logical structure which
4950: contains graphical elements:</p>
4951: <pre>Design = LIST OF (ElemGraph = GRAPHICS);</pre>
4952: <p>
1.3 cvs 4953: The following rules allow the user to freely choose the position of each
1.18 cvs 4954: element when it is created:</p>
4955: <pre>ElemGraph =
1.1 cvs 4956: BEGIN
4957: VertPos : Top = Enclosing . Top + 1 cm UserSpecified;
4958: HorizPos: Left = Enclosing . Left UserSpecified;
4959: ...
1.18 cvs 4960: END;</pre>
4961: <p>
4962: Thus, when a graphical element is created, its default placement is at the
4963: left of the window and 1 cm from the top, but the user can move it
4964: immediately, simply by moving the mouse.</p>
4965: </blockquote>
4966: </div>
1.1 cvs 4967:
1.18 cvs 4968: <div class="subsection">
1.1 cvs 4969:
1.18 cvs 4970: <h3><a name="sectc4219">Box extents</a></h3>
4971: <p>
1.1 cvs 4972: The extents (height and width) of each box are defined by the two rules
1.18 cvs 4973: <tt>Height</tt> and <tt>Width</tt>. There are three types of extents: fixed,
4974: relative, and elastic.</p>
1.1 cvs 4975:
1.18 cvs 4976: <div class="subsubsection">
1.1 cvs 4977:
1.18 cvs 4978: <h4><a name="sectd42191">Fixed extents</a></h4>
4979: <p>
1.1 cvs 4980: A fixed dimension sets the height or width of the box independently of all
1.18 cvs 4981: other boxes. It is expressed in <a href="#sectc4217">distance units</a>. The
4982: extent can be followed by the <tt>UserSpecified</tt> keyword which indicates
1.1 cvs 4983: that when the element to which the rule applies is being created, the editor
4984: will ask the user to specify the extent himself, using the mouse. In this
4985: case, the extent specified in the rule is a default extent which is suggested
1.18 cvs 4986: to the user but can be modified. The <tt>UserSpecified</tt> keyword can be
4987: used either in the <tt>Height</tt> rule, the <tt>Width</tt> rule, or both.</p>
4988: <p>
4989: A fixed extent rule can be ended by the <tt>Min</tt> keyword, which signifies
1.1 cvs 4990: that the indicated value is a minimum, and that, if the contents of the box
1.18 cvs 4991: require it, a larger extent is possible.</p>
4992: <pre> 'Height' ':' Dimension
1.1 cvs 4993: 'Width' ':' Dimension
4994: Dimension = AbsDist [ 'UserSpecified' ] [ 'Min' ] /
1.18 cvs 4995: ...</pre>
4996: <blockquote class="example">
4997: <p>
4998: <strong>Example:</strong></p>
4999: <p>
5000: Continuing with the <a href="#expos2">previous example</a>, it is possible to
1.3 cvs 5001: allow the user to choose the size of each graphical element as it is
1.18 cvs 5002: created:</p>
5003: <pre>ElemGraph : BEGIN
1.6 cvs 5004: Width : 2 cm UserSpecified;
1.1 cvs 5005: Height : 1 cm UserSpecified;
5006: ...
1.18 cvs 5007: END;</pre>
5008: <p>
1.1 cvs 5009: Thus, when a graphical element is create, it is drawn by default with a width
5010: of 2 cm and a height of 1 cm, but the user is free to resize it immediately
1.18 cvs 5011: with the mouse.</p>
5012: <pre>Summary : BEGIN
1.1 cvs 5013: Height : 5 cm Min;
5014: ...
5015: END;
5016: Keywords : BEGIN
5017: VertPos : Top = Summary . Bottom;
5018: ...
1.18 cvs 5019: END;</pre>
5020: </blockquote>
5021: </div>
1.1 cvs 5022:
1.18 cvs 5023: <div class="subsubsection">
1.1 cvs 5024:
1.18 cvs 5025: <h4><a name="sectd42192">Relative extents</a></h4>
5026: <p>
1.1 cvs 5027: A relative extent determines the extent as a function of the extent of another
5028: box, just as a relative position places a box in relation to another. The
5029: reference box in an extent rule is designated using the same syntax as is used
1.18 cvs 5030: in a relative position rule. It is followed by a period and a <tt>Height</tt>
5031: or <tt>Width</tt> keyword, depending on the extent being referred to. Next
1.1 cvs 5032: comes the relation between the extent being defined and the extent of the
1.18 cvs 5033: reference box. This relation can be either a percentage or a difference.</p>
5034: <p>
1.1 cvs 5035: A percentage is indicated by a star (the multiplication symbol) followed by
5036: the numeric percentage value (which may be greater than or less than 100) and
5037: the percent (`%') character. A difference is simply indicated by a signed
1.18 cvs 5038: difference.</p>
5039: <p>
1.1 cvs 5040: If the rule appears in the presentation rules of a numeric attribute, the
5041: percentage value can be replaced by the name of the attribute. This attribute
1.18 cvs 5042: is then used as a percentage. The attribute can also be used as part of a <a
5043: href="#distance">difference</a>.</p>
5044: <p>
1.1 cvs 5045: Just as with a fixed extent, a relative extent rule can end with the
1.18 cvs 5046: <tt>Min</tt> keyword, which signifies that the extent is a minimum and that,
5047: if the contents of the box require it, a larger extent is possible.</p>
5048: <p>
5049: A special case of relative extent rules is:</p>
5050: <pre>Height : Enclosed . Height;</pre>
5051: <p>
5052: or</p>
5053: <pre>Width : Enclosed . Width;</pre>
5054: <p>
1.5 cvs 5055: which specifies that the box has a height (or width) such that it encloses all
1.18 cvs 5056: the boxes which it contains, excluding boxes having a rule <tt>VertOverflow:
5057: Yes;</tt> or <tt>HorizOverflow: Yes;</tt>.</p>
5058: <p>
5059: <strong>Note:</strong> character strings (type <tt>TEXT_UNIT</tt>) generally
1.1 cvs 5060: must use the sum of the widths of the characters which compose them as their
1.18 cvs 5061: width, which is expressed by the rule:</p>
5062: <pre>TEXT_UNIT :
5063: Width : Enclosed . Width;</pre>
5064: <p>
5065: If this rule is not the default <tt>Width</tt> rule, it must be given
5066: explicitly in the <tt>RULES</tt> section which defines the presentation rules
5067: of the logical elements.</p>
5068: <pre> 'Height' ':' Extent
1.1 cvs 5069: 'Width' ':' Extent
5070: Extent = Reference '.' HeightWidth [ Relation ]
5071: [ 'Min' ] / ...
5072: HeightWidth ='Height' / 'Width' .
5073: Relation ='*' ExtentAttr '%' / Distance .
5074: ExtentAttr = ExtentVal / AttrID .
1.18 cvs 5075: ExtentVal = NUMBER .</pre>
5076: <blockquote class="example">
5077: <p>
5078: <strong>Example:</strong></p>
5079: <p>
5080: Completing the <a href="#expos1">above example</a>, it is possible to specify
5081: that the report takes its width from the editing window and its height from
5082: the size of its contents (this can obviously be greater than that of the
5083: window):</p>
5084: <pre>Report : BEGIN
1.1 cvs 5085: Width : Enclosing . Width;
5086: Height : Enclosed . Height;
5087: ...
1.18 cvs 5088: END;</pre>
5089: <p>
1.3 cvs 5090: Then, the following rules make the title occupy 60% of the width of the report
5091: (which is that of the window) and is broken into centered lines of this width
1.18 cvs 5092: (see the <a href="#sectc4222"><tt>Line</tt> rule</a>).</p>
5093: <pre>Title : BEGIN
1.1 cvs 5094: Width : Enclosing . Width * 60%;
5095: Height : Enclosed . Height;
5096: Line;
5097: Adjust : VMiddle;
5098: ...
1.18 cvs 5099: END;</pre>
5100: <p>
5101: The summary occupy the entire width of the window, with the exception of a 2
5102: cm margin reserved by the horizontal position rule:</p>
5103: <pre>Summary : BEGIN
1.1 cvs 5104: Width : Enclosing . Width - 2 cm;
5105: Height : Enclosed . Height;
5106: ...
1.18 cvs 5107: END;</pre>
5108: <p>
5109: This set of rules, plus the <a href="#reportexample">position rules given
5110: above</a>, produce the layout of boxes shown in the following<a
5111: href="#posdim">figure</a>.</p>
5112:
5113: <div class="figure">
5114: <hr>
1.19 cvs 5115:
1.18 cvs 5116: <pre>-------------------------------------------------------------
1.1 cvs 5117: | Window and Report ^ |
5118: | | 1 line |
5119: | v |
5120: | ------------------------------------- |
5121: | | | |
5122: : 20% : Title : 20% :
5123: :<--------->: :<--------->:
5124: : : 60% : :
5125: : :<--------------------------------->: :
5126: | | | |
5127: | ------------------------------------- |
5128: | ^ |
5129: | | 1.5 line |
5130: | | |
5131: | v |
5132: | ---------------------------------------------------|
5133: | 2 cm | |
5134: |<------>| Summary |
1.18 cvs 5135: : : :</pre>
1.19 cvs 5136: <p align="center">
1.18 cvs 5137: <em><a name="posdim">Box position and extent</a><em></em></em></p>
5138: <hr>
1.19 cvs 5139:
1.18 cvs 5140: </div>
5141: </blockquote>
5142: </div>
1.1 cvs 5143:
1.18 cvs 5144: <div class="subsubsection">
1.1 cvs 5145:
1.18 cvs 5146: <h4><a name="sectd42193">Elastic extents</a></h4>
5147: <p>
1.1 cvs 5148: The last type of extent is the elastic extent. Either one or both extents can
5149: be elastic. A box has an elastic extent when two opposite sides are linked by
1.18 cvs 5150: distance constraints to two sides or axes of other boxes.</p>
5151: <p>
1.1 cvs 5152: One of the sides of the elastic box is linked by a position rule
1.18 cvs 5153: (<tt>VertPos</tt> or <tt>HorizPos</tt>) to a neighboring box. The other side
5154: is link to another box by a <tt>Height</tt> or <tt>Width</tt> rule, which
1.1 cvs 5155: takes the same form as the position rule. For the elastic box itself, the
5156: notions of sides (left or right, top or bottom) are fuzzy, since the movement
5157: of either one of the two reference boxes can, for example, make the left side
5158: of the elastic box move to the right of its right side. This is not
5159: important. The only requirement is that the two sides of the elastic box used
1.18 cvs 5160: in the position and extent rule are opposite sides of the box.</p>
5161: <pre> 'Height' ':' Extent
1.6 cvs 5162: 'Width' ':' Extent
1.18 cvs 5163: Extent = HPos / VPos / ...</pre>
5164: <blockquote class="example">
5165: <p>
5166: <strong>Example:</strong></p>
5167: <p>
1.3 cvs 5168: Suppose we want to draw an elastic arrow or line between the middle of the
5169: bottom side of box A and the upper left corner of box B. To do this, we would
5170: define a graphics box whose upper left corner coincides with the middle of the
5171: bottom side of A (a position rule) and whose lower right corner coincides with
1.18 cvs 5172: with the upper left corner of B (dimension rules):</p>
5173: <pre>LinkedBox :
1.1 cvs 5174: BEGIN
1.6 cvs 5175: VertPos : Top = A .Bottom;
1.1 cvs 5176: HorizPos : Left = A . VMiddle;
1.6 cvs 5177: Height : Bottom = B . Top;
5178: Width : Right = B . Left;
1.18 cvs 5179: END;</pre>
5180: </blockquote>
5181: <blockquote class="example">
5182: <p>
5183: <strong>Example:</strong></p>
5184: <p>
1.3 cvs 5185: The element SectionTitle creates a presentation box called SectionNum which
5186: contains the number of the section. Suppose we want to align the SectionNum
5187: and SectionTitle horizontally, have the SectionNum take its width from its
5188: contents (the section number), have the SectionTitle box begin 0.5 cm to the
5189: right of the SectionNum box and end at the right edge of its enclosing box.
1.18 cvs 5190: This would make the SectionTitle box elastic, since its width is defined by
5191: the position of its left and right sides. The following rules produce this
5192: effect:</p>
5193: <pre>SectionNum :
1.1 cvs 5194: BEGIN
5195: HorizPos : Left = Enclosing . Left;
5196: Width : Enclosed . Width;
5197: ...
5198: END;
5199:
5200: SectionTitle :
5201: BEGIN
5202: HorizPos : Left = SectionNum . Right + 0.5 cm;
5203: Width : Right = Enclosing . Right;
5204: ...
1.18 cvs 5205: END;</pre>
5206: </blockquote>
5207: </div>
5208: </div>
1.1 cvs 5209:
1.18 cvs 5210: <div class="subsection">
1.1 cvs 5211:
1.18 cvs 5212: <h3><a name="sectc4220">Overflow</a></h3>
5213: <p>
1.1 cvs 5214: A boxes corresponding to a structural element normally contain all boxes
5215: corresponding to the elements of its subtree. However, in some cases, it
5216: could be necessary to allow a box to jut out from its parent box. Two
5217: presentation rules indicate that such an overflow is allowed, one for
1.18 cvs 5218: horizontal overflow, one for vertical overflow.</p>
5219: <p>
1.1 cvs 5220: Each of these rules is expressed by a keyword followed by a colon and the
1.18 cvs 5221: keyword <tt>Yes</tt> or <tt>No</tt>.</p>
5222: <pre> 'VertOverflow' ':' Boolean /
1.1 cvs 5223: 'HorizOverflow' ':' Boolean .
1.18 cvs 5224: Boolean = 'Yes' / 'No' .</pre>
5225: </div>
1.1 cvs 5226:
1.26 cvs 5227: <p>@@@@@ ****** </p>
5228: <p>Explain Margin, Padding and Border. Refer to CSS2.</p>
5229: <pre> 'MarginTop' ':' MarginWidth /
5230: 'MarginRight' ':' MarginWidth /
5231: 'MarginBottom' ':' MarginWidth /
5232: 'MarginLeft' ':' MarginWidth /
5233: 'PaddingTop' ':' PaddingWidth /
5234: 'PaddingRight' ':' PaddingWidth /
5235: 'PaddingBottom' ':' PaddingWidth /
5236: 'PaddingLeft' ':' PaddingWidth /
5237: 'BorderTopWidth' ':' BorderWidth /
5238: 'BorderRightWidth' ':' BorderWidth /
5239: 'BorderBottomWidth' ':' BorderWidth /
5240: 'BorderLeftWidth' ':' BorderWidth /
5241: 'BorderTopColor' ':' BorderColor /
5242: 'BorderRightColor' ':' BorderColor /
5243: 'BorderBottomColor' ':' BorderColor /
5244: 'BorderLeftColor' ':' BorderColor /
5245: 'BorderTopStyle' ':' BorderStyle /
5246: 'BorderRightStyle' ':' BorderStyle /
5247: 'BorderBottomStyle' ':' BorderStyle /
5248: 'BorderLeftStyle' ':' BorderStyle .
5249:
5250: MarginWidth = InheritParent / 'Auto' / Distance .
5251: PaddingWidth = InheritParent / Distance .
5252: BorderWidth = InheritParent / 'Thin' / 'Medium' / 'Thick' / Distance .
5253: BorderColor = InheritParent / 'Transparent' / 'Foreground' /
5254: ColorName .
5255: BorderStyle = InheritParent /
5256: 'None' / 'Hidden' / 'Dotted' / 'Dashed' / 'Solid' /
5257: 'Double' / 'Groove' / 'Ridge' / 'Inset' / 'Outset' .
1.27 cvs 5258: InheritParent = 'Enclosing' '=' / 'Creator' '=' .
1.26 cvs 5259: ColorName = NAME .</pre>
5260: <p>@@@@@ ****** </p>
5261:
1.18 cvs 5262: <div class="subsection">
1.1 cvs 5263:
1.18 cvs 5264: <h3><a name="sectc4221">Inheritance</a></h3>
5265: <p>
1.1 cvs 5266: A presentation parameter can be defined by reference to the same parameter of
5267: another box in the tree of boxes. These structural links are expressed by
5268: kinship. The reference box can be that of the element immediately above in
1.18 cvs 5269: the structure (<tt>Enclosing</tt>), two levels above (<tt>GrandFather</tt>),
5270: immediately below (<tt>Enclosed</tt>) or immediately before
5271: (<tt>Previous</tt>). In the case of a presentation box, and only in that
1.1 cvs 5272: case, the reference box may be the element which created the presentation box
1.18 cvs 5273: (<tt>Creator</tt>).</p>
5274: <p>
1.1 cvs 5275: Kinship is expressed in terms of the logical structure of the document and not
5276: in terms of the tree of boxes. The presentation box cannot transmit any of
5277: their parameters by inheritance; only structured element boxes can do so. As
5278: an example, consider an element B which follows an element A in the logical
5279: structure. The element B creates a presentation box P in front of itself,
1.18 cvs 5280: using the <tt>CreateBefore</tt> rule (see the <a href="#sectc4232">creation
5281: rules</a>). If element B's box inherits its character style using the
5282: <tt>Previous</tt> kinship operation, it gets its character style from A's box,
1.1 cvs 5283: not from P's box. Inheritance works differently for positions and extents,
1.18 cvs 5284: which can refer to presentation boxes.</p>
5285: <p>
1.1 cvs 5286: The inherited parameter value can be the same as that of the reference box.
5287: This is indicated by an equals sign. However, for numeric parameters, a
5288: different value can be obtained by adding or subtracting a number from the
5289: reference box's parameter value. Addition is indicated by a plus sign before
5290: the number, while subtraction is specified with a minus sign. The value of a
5291: parameter can also be given a maximum (if the sign is a plus) or minimum (if
1.18 cvs 5292: the sign is a minus).</p>
5293: <p>
1.1 cvs 5294: If the rule is being applied to a numeric attribute, the number to add or
5295: subtract can be replaced by the attribute name. The value of a maximum or
5296: minimum may also be replaced by an attribute name. In these cases, the value
1.18 cvs 5297: of the attribute is used.</p>
5298: <pre> Inheritance = Kinship InheritedValue .
1.6 cvs 5299: Kinship ='Enclosing' / 'GrandFather' / 'Enclosed' /
5300: 'Previous' / 'Creator' .
1.1 cvs 5301: InheritedValue ='+' PosIntAttr [ 'Max' maximumA ] /
1.6 cvs 5302: '-' NegIntAttr [ 'Min' minimumA ] /
5303: '=' .
5304: PosIntAttr = PosInt / AttrID .
5305: PosInt = NUMBER .
5306: NegIntAttr = NegInt / AttrID .
5307: NegInt = NUMBER .
5308: maximumA = maximum / AttrID .
5309: maximum = NUMBER .
5310: minimumA = minimum / AttrID .
1.18 cvs 5311: minimum = NUMBER .</pre>
5312: <p>
1.1 cvs 5313: The parameters which can be obtained by inheritance are justification,
5314: hyphenation, interline spacing, character font (font family), font style, font
5315: size, visibility, indentation, underlining, alignment of text, stacking order
5316: of objects, the style and thickness of lines, fill pattern and the colors of
1.18 cvs 5317: lines and characters.</p>
5318: </div>
1.1 cvs 5319:
1.18 cvs 5320: <div class="subsection">
1.1 cvs 5321:
1.18 cvs 5322: <h3><a name="sectc4222">Line breaking</a></h3>
5323: <p>
5324: The <tt>Line</tt> rule specifies that the contents of the box should be broken
1.1 cvs 5325: into lines: the boxes included in the box to which this rule is attached are
5326: displayed one after the other, from left to right, with their horizontal
5327: reference axes aligned so that they form a series of lines. The length of
1.18 cvs 5328: these lines is equal to the width of the box to which the <tt>Line</tt> rule
5329: is attached.</p>
5330: <p>
1.1 cvs 5331: When an included box overflows the current line, it is either carried forward
1.18 cvs 5332: to the next line, cur, or left the way it is. The <a
5333: href="#sectc4223"><tt>LineBreak</tt> rule</a> is used to allow or prevent the
1.1 cvs 5334: breaking of included boxes. If the included box is not breakable but is
5335: longer than the space remaining on the line, it is left as is. When a
5336: character string box is breakable, the line is broken between words or, if
1.18 cvs 5337: necessary, by <a href="#sectd42225">hyphenating a word</a>. When a compound
5338: box is breakable, the box is transparent in regard to line breaking. The boxes
5339: included in the compound box are treated just like included boxes which have
5340: the <tt>LineBreak</tt> rule. Thus, it is possible to traverse a complete
5341: subtree of boxes to line break the text leaves of a complex structure.</p>
5342: <p>
1.1 cvs 5343: The relative position rules of the included boxes are ignored, since the boxes
1.18 cvs 5344: will be placed according to the line breaking rules.</p>
5345: <p>
5346: The <tt>Line</tt> rule does not have a parameter. The characteristics of the
5347: lines that will be constructed are determined by the <tt>LineSpacing</tt>,
5348: <tt>Indent</tt>, <tt>Adjust</tt>, <tt>Justify</tt>, and <tt>Hyphenate</tt>
5349: rules. Moreover, the <a href="#insectd42226"><tt>Inline</tt> rule</a> permits
5350: the exclusion of certain elements from the line breaking process.</p>
5351: <p>
5352: When the <tt>Line</tt> rule appears in the rules sequence of a non-primary
5353: view, it applies only to that view, but when the <tt>Line</tt> rule appears in
1.1 cvs 5354: the rules sequence of the primary view, it also applies to the other views by
1.18 cvs 5355: default, except for those views which explicitly invoke the <tt>NoLine</tt>
5356: rule. Thus, the <tt>NoLine</tt> rule can be used in a non-primary view to
5357: override the primary view's <tt>Line</tt> rule. The <tt>NoLine</tt> rule must
5358: not be used with the primary view because the absence of the <tt>Line</tt>
5359: rule has the same effect. Like the <tt>Line</tt> rule, the <tt>NoLine</tt>
5360: rule does not take any parameters.</p>
5361: <pre> 'Line'
5362: 'NoLine'</pre>
5363:
5364: <div class="subsubsection">
5365:
5366: <h4><a name="sectd42221">Line spacing</a></h4>
5367: <p>
5368: The <tt>LineSpacing</tt> rule defines the line spacing to be used in the line
1.1 cvs 5369: breaking process. The line spacing is the distance between the baselines
5370: (horizontal reference axis) of the successive lines produced by the
1.18 cvs 5371: <tt>Line</tt> rule. The value of the line spacing can be specified as a
5372: constant or by inheritance. It is expressed in any of the available <a
5373: href="#sectc4217">distance units</a>.</p>
5374: <p>
1.1 cvs 5375: Inheritance allows the value to be obtained from a relative in the structure
5376: tree, either without change (an equals sign appears after the inheritance
5377: keyword), with a positive difference (a plus sign), or a negative difference
5378: (a minus sign). When the rule uses a difference, the value of the difference
1.18 cvs 5379: follows the sign and is expressed as a <a href="#sectc4217">distance</a>.</p>
5380: <pre> 'LineSpacing' ':' DistOrInherit
1.6 cvs 5381: DistOrInherit = Kinship InheritedDist / Distance .
1.18 cvs 5382: InheritedDist = '=' / '+' AbsDist / '-' AbsDist .</pre>
5383: <p>
1.1 cvs 5384: When the line spacing value (or its difference from another element) is
5385: expressed in relative units, it changes with the size of the characters. Thus,
5386: when a larger font is chosen for a part of the document, the line spacing of
5387: that part expands proportionally. In contrast, when the line spacing value is
5388: expressed in absolute units (centimeters, inches, typographer's points), it is
5389: independent of the characters, which permits the maintenance of a consistent
5390: line spacing, whatever the character font. Either approach can be taken,
1.18 cvs 5391: depending on the desired effect.</p>
5392: </div>
1.1 cvs 5393:
1.18 cvs 5394: <div class="subsubsection">
1.1 cvs 5395:
1.18 cvs 5396: <h4><a name="sectd42222">First line indentation</a></h4>
5397: <p>
5398: The <tt>Indent</tt> rule is used to specify the indentation of the first line
5399: of the elements broken into lines by the <tt>Line</tt> function. The
1.1 cvs 5400: indentation determines how far the first line of the element is shifted with
5401: respect to the other lines of the same element. It can be specified as a
5402: constant or by inheritance. The constant value is a positive integer (shifted
5403: to the right; the sign is optional), a negative integer (shifted to the left)
1.18 cvs 5404: or zero (no shift). All available <a href="#sectc4217">units</a> can be
5405: used.</p>
5406: <p>
1.1 cvs 5407: Indentation can be defined for any box, regardless of whether the box is line
5408: broken, and transmitted by inheritance to elements that are line broken. The
1.18 cvs 5409: size of the indentation is specified in the same manner as the <a
5410: href="#sectd42221">line spacing</a>.</p>
5411: <pre> 'Indent' ':' DistOrInherit</pre>
5412: </div>
1.1 cvs 5413:
1.18 cvs 5414: <div class="subsubsection">
1.1 cvs 5415:
1.18 cvs 5416: <h4><a name="sectd42223">Alignment</a></h4>
5417: <p>
1.1 cvs 5418: The alignment style of the lines constructed during line breaking is defined
1.18 cvs 5419: by the <tt>Adjust</tt> rule. The alignment value can be a constant or
5420: inherited. A constant value is specified by a keyword:</p>
5421: <ul>
5422: <li>
5423: <tt>Left</tt>: at the left edge,
1.19 cvs 5424: </li>
1.18 cvs 5425: <li>
5426: <tt>Right</tt>: at the right edge,
1.19 cvs 5427: </li>
1.18 cvs 5428: <li>
5429: <tt>VMiddle</tt>: centered
1.19 cvs 5430: </li>
1.18 cvs 5431: <li>
5432: <tt>LeftWithDots</tt>: at the left edge with a dotted line filling out the
1.1 cvs 5433: last line up to the right edge of the line breaking box.
1.19 cvs 5434: </li>
1.18 cvs 5435: </ul>
5436: <p>
1.1 cvs 5437: An inherited value can only be the same as that of the reference box and is
1.18 cvs 5438: specified by a kinship keyword followed by an equals sign.</p>
5439: <pre> 'Adjust' ':' AlignOrInherit
1.1 cvs 5440: AlignOrInherit = Kinship '=' / Alignment .
5441: Alignment = 'Left' / 'Right' / 'VMiddle' /
1.18 cvs 5442: 'LeftWithDots' .</pre>
5443: </div>
1.1 cvs 5444:
1.18 cvs 5445: <div class="subsubsection">
1.1 cvs 5446:
1.18 cvs 5447: <h4><a name="sectd42224">Justification</a></h4>
5448: <p>
5449: The <tt>Justify</tt> rule indicates whether the lines contained in the box and
5450: produced by a <tt>Line</tt> rule should be extended horizontally to occupy the
1.1 cvs 5451: entire width of their enclosing box. The first and last lines are treated
5452: specially: the position of the beginning of the first line is fixed by the
1.18 cvs 5453: <tt>Indent</tt> rule and last line is not extended. The justification
1.1 cvs 5454: parameter defined by this rule takes a boolean value, which can be a constant
5455: or inherited. A constant boolean value is expressed by either the
1.18 cvs 5456: <tt>Yes</tt> or the <tt>No</tt> keyword. An inherited value can only be the
1.1 cvs 5457: same as that of the reference box and is specified by a kinship keyword
1.18 cvs 5458: followed by an equals sign.</p>
5459: <pre> 'Justify' ':' BoolInherit
1.1 cvs 5460: BoolInherit = Boolean / Kinship '=' .
1.18 cvs 5461: Boolean ='Yes' / 'No' .</pre>
5462: <p>
1.1 cvs 5463: When the lines are justified, the alignment parameter specified in the
1.18 cvs 5464: <tt>Adjust</tt> rule has no influence, other than on the last line produced.
1.1 cvs 5465: This occurs because, when the other are extended to the limits of the box, the
1.18 cvs 5466: alignment style is no longer perceptible.</p>
5467: <blockquote class="example">
5468: <p>
5469: <strong>Example:</strong></p>
5470: <p>
1.3 cvs 5471: An important use of inheritance is to vary the characteristics of lines for an
5472: element type (for example, Paragraph) according to the enclosing environment
5473: (for example, Summary or Section), and thus obtain different line breaking
5474: styles for the same elements when they appear in different environments. The
1.18 cvs 5475: following rules specify that paragraphs inherit their alignment,
5476: justification, and line spacing:</p>
5477: <pre>Paragraph :
1.1 cvs 5478: BEGIN
5479: Justify : Enclosing = ;
5480: LineSpacing : Enclosing = ;
5481: Adjust : Enclosing =;
5482: Line;
1.18 cvs 5483: END;</pre>
5484: <p>
1.5 cvs 5485: If the alignment, justification, and line spacing of the Section and Summary
1.18 cvs 5486: elements is fixed:</p>
5487: <pre>Section :
1.1 cvs 5488: BEGIN
5489: Adjust : Left;
5490: Justify : Yes;
5491: LineSpacing : 1;
5492: END;
5493: Summary :
5494: BEGIN
5495: Adjust : VMiddle;
5496: Justify : No;
5497: LineSpacing : 1.3;
1.18 cvs 5498: END;</pre>
5499: <p>
1.4 cvs 5500: then the paragraphs appearing in sections are justified with a simple line
5501: spacing while those appearing in summaries are centered and not justified and
5502: have a larger line spacing. These are nevertheless the very same type of
1.18 cvs 5503: paragraph defined in the logical structure schema.</p>
5504: </blockquote>
5505: </div>
5506:
5507: <div class="subsubsection">
5508:
5509: <h4><a name="sectd42225">Hyphenation</a></h4>
5510: <p>
5511: The <tt>Hyphenate</tt> rule indicates whether or not words should be broken by
1.1 cvs 5512: hyphenation at the end of lines. It affects the lines produced by the
1.18 cvs 5513: <tt>Line</tt> rule and contained in the box carrying the <tt>Hyphenate</tt>
5514: rule.</p>
5515: <p>
1.1 cvs 5516: The hyphenation parameter takes a boolean value, which can be either constant
5517: or inherited. A constant boolean value is expressed by either the
1.18 cvs 5518: <tt>Yes</tt> or the <tt>No</tt> keyword. An inherited value can only be the
1.1 cvs 5519: same as that of the reference box and is specified by a kinship keyword
1.18 cvs 5520: followed by an equals sign.</p>
5521: <pre> 'Hyphenate' ':' BoolInherit
1.1 cvs 5522: BoolInherit = Boolean / Kinship '=' .
1.18 cvs 5523: Boolean = 'Yes' / 'No' .</pre>
5524: </div>
5525:
5526: <div class="subsubsection">
5527:
5528: <h4><a name="sectd42226">Avoiding line breaking</a></h4>
5529: <p>
5530: The <tt>InLine</tt> rule is used to specify that a box that would otherwise
5531: participate in line breaking asked for by the <tt>Line</tt> rule of an
1.1 cvs 5532: enclosing box, instead avoids the line breaking process and positions itself
1.18 cvs 5533: according to the <tt>HorizPos</tt> and <tt>VertPos</tt> rules that apply to
5534: it. When the <tt>InLine</tt> rule applies to a box which would not be line
5535: broken, it has no effect.</p>
5536: <p>
5537: The rule is expressed by the <tt>InLine</tt> keyword followed by a colon and
5538: the keyword <tt>Yes</tt>, if the box should participate in line breaking, or
5539: the keyword <tt>No</tt>, if it should not. This is the only form possible:
1.1 cvs 5540: this rule cannot be inherited. Moreover, it can only appear in the rules of
5541: the primary view and applies to all views defined in the presentation
1.18 cvs 5542: schema.</p>
5543: <pre> 'InLine' ':' Boolean .
5544: Boolean = 'Yes' / 'No' .</pre>
5545: <blockquote class="example">
5546: <p>
5547: <strong>Example:</strong></p>
5548: <p>
5549: Suppose the structure schema defines a logical attribute called <tt>New</tt>
5550: which is used to identify the passages in a document which were recently
5551: modified. It would be nice to have the presentation schema make a bar appear
5552: in the left margin next to each passage having the <tt>New</tt> attribute. A
5553: new passage can be an entire element, such as a paragraph or section, or it
5554: can be some words in the middle of a paragraph. To produce the desired
5555: effect, the <tt>New</tt> attribute is given a creation rule which generates a
5556: <tt>VerticalBar</tt> presentation box.</p>
5557: <p>
5558: When the <tt>New</tt> attribute is attached to a character string which is
1.1 cvs 5559: inside a line broken element (inside a paragraph, for example), the bar is one
5560: of the elements which participates in line breaking and it is placed normally
5561: in the current line, at the end of the character string which has the
1.18 cvs 5562: attribute. To avoid this, the <tt>InLine</tt> rule is used in the following
5563: way:</p>
5564: <pre>BOXES
1.1 cvs 5565: VerticalBar:
5566: BEGIN
5567: Content: Graphics 'l';
5568: HorizPos: Left = Root . Left;
5569: VertPos: Top = Creator . Top;
5570: Height: Bottom = Creator . Bottom;
5571: Width: 1 pt;
5572: InLine: No;
5573: ...
5574: END;
5575: ...
5576: ATTRIBUTES
5577: Nouveau:
5578: BEGIN
5579: CreateAfter(VerticalBar);
1.18 cvs 5580: END;</pre>
5581: </blockquote>
5582: </div>
5583: </div>
1.1 cvs 5584:
1.18 cvs 5585: <div class="subsection">
1.1 cvs 5586:
1.18 cvs 5587: <h3><a name="sectc4223">Page breaking and line breaking conditions</a></h3>
5588: <p>
1.1 cvs 5589: Pages are constructed by the editor in accordance with the model specified by
1.18 cvs 5590: a <a href="#sectc4233"><tt>Page</tt> rule</a>. The page model describes only
5591: the composition of the pages but does not give any rules for breaking
5592: different element types across pages. Now, it is possible that certain
5593: elements must not be cut by page breaks, while others can be cut anywhere. The
5594: <tt>PageBreak</tt>, <tt>NoBreak1</tt>, and <tt>NoBreak2</tt> rules are used to
5595: specify the conditions under which each element type can be cut.</p>
5596: <p>
5597: The <tt>PageBreak</tt> rule is used to indicate whether or not the box can be
1.1 cvs 5598: cut during the construction of pages. If cutting is authorized, the box can
5599: be cut, with one part appearing at the bottom of a page and the other part
5600: appearing at the top of the next page. The rule is formed by the
1.18 cvs 5601: <tt>PageBreak</tt> keyword followed by a colon and a constant boolean value
5602: (<tt>Yes</tt> or <tt>No</tt>). This is the only form possible: this rule
1.1 cvs 5603: cannot be inherited. Moreover, it can only appear in the rules of the primary
1.18 cvs 5604: view and applies to all views defined in the presentation schema.</p>
5605: <p>
1.1 cvs 5606: Whether objects can be cut by line breaks can be controlled in a similar way
1.18 cvs 5607: using the <tt>LineBreak</tt> rule. This rule allows the specification of
1.1 cvs 5608: whether or not the box can be cut during the construction of lines. If
5609: cutting is authorized, the box can be cut, with one part appearing at the end
5610: of a line and the other part appearing at the beginning of the next line. The
1.18 cvs 5611: rule is formed by the <tt>LineBreak</tt> keyword followed by a colon and a
5612: constant boolean value (<tt>Yes</tt> or <tt>No</tt>). This is the only form
1.1 cvs 5613: possible: this rule cannot be inherited. Moreover, it can only appear in the
5614: rules of the primary view and applies to all views defined in the presentation
1.18 cvs 5615: schema.</p>
5616: <pre> 'PageBreak' ':' Boolean .
1.1 cvs 5617: 'LineBreak' ':' Boolean .
1.18 cvs 5618: Boolean = 'Yes' / 'No' .</pre>
5619: <p>
1.1 cvs 5620: When a box can be cut by a page break, it is possible that a page break will
5621: fall an inappropriate spot, creating, for example, a widow or orphan, or
5622: separating the title of a section from the first paragraph of the section. The
1.18 cvs 5623: <tt>NoBreak1</tt> and <tt>NoBreak2</tt> rules are used to avoid this. They
5624: specify that the box of the element to which they apply cannot be cut within a
5625: certain zone at the top (<tt>NoBreak1</tt> rule) or at the bottom
5626: (<tt>NoBreak2</tt> rule). These two rules specify the height of the zones in
5627: which page breaks are prohibited.</p>
5628: <p>
5629: The <tt>NoBreak1</tt> and <tt>NoBreak2</tt> rules give the height of the zone
1.1 cvs 5630: in which page breaking is prohibited. The height is given as a constant value
1.18 cvs 5631: using any of the <a href="#sectc4217">available units</a>, absolute or
5632: relative. The value may not be inherited.</p>
5633: <pre> 'NoBreak1' ':' AbsDist .
5634: 'NoBreak2' ':' AbsDist .</pre>
5635: <blockquote class="example">
5636: <p>
5637: <strong>Example:</strong></p>
5638: <p>
5639: The following rules prevent widows and orphans in a paragraph:</p>
5640: <pre>Paragraph :
1.1 cvs 5641: BEGIN
5642: NoBreak1 : 2;
5643: NoBreak2 : 2;
1.18 cvs 5644: END;</pre>
5645: <p>
1.3 cvs 5646: This rule prevents a section title from becoming separated from the first
5647: paragraph of the section by prohibiting page breaks at the beginning of the
1.18 cvs 5648: section rule:</p>
5649: <pre>Section :
5650: NoBreak1 : 1.5 cm;</pre>
5651: <p>
5652: Finally, this rule prevents a figure from being page broken in any way:</p>
5653: <pre>Figure :
5654: PageBreak : No;</pre>
5655: </blockquote>
5656: <p>
1.1 cvs 5657: The Thot editor constructs the document images displayed on the screen
5658: dynamically. As the user moves in the document or makes the document scroll
5659: in a window, the editor constructs the image to be displayed in little bits,
5660: filling the gaps which are produced in the course of these operations. It
5661: stops filling in the image when an element reaches the edge of the window in
5662: which the gap appears. If the appearance of the document is complex, it is
5663: possible that the image in incomplete, even though the edge of the window was
5664: reached. For example, an element might need to be presented to the side of
5665: the last element displayed, but its image was not constructed. The user will
5666: not know whether the element is really absent or if its image has simply not
1.18 cvs 5667: been constructed.</p>
5668: <p>
5669: The <tt>Gather</tt> rule is used to remedy this problem. When the rule
5670: <tt>Gather : Yes;</tt> is associated with an element type, the image of such
5671: elements is constructed as a block by the editor: it is never split up.</p>
5672: <p>
5673: The <tt>Gather</tt> rule may not appear in the <a href="#sectc427">default
5674: rules</a>. Elements which do not have the <tt>Gather</tt> rule are considered
5675: susceptible to being split up during display. Thus, it is not necessary to
5676: use the <tt>Gather : No;</tt> form. This rule must be used prudently and only
5677: for those elements which truly need it. If used incorrectly, it can
5678: pointlessly increase the size of the image constructed by the editor and lead
5679: to excessive memory consumption by the editor.</p>
5680: <p>
5681: Like the <tt>PageBreak</tt> and <tt>LineBreak</tt> rules, the <tt>Gather</tt>
1.1 cvs 5682: rule can only appear in rules of the primary view and applies to all views
1.18 cvs 5683: defined in the presentation schema.</p>
5684: <pre> 'Gather' ':' Boolean .</pre>
5685: </div>
1.1 cvs 5686:
1.18 cvs 5687: <div class="subsection">
1.1 cvs 5688:
1.18 cvs 5689: <h3><a name="sectc4224">Visibility</a></h3>
5690: <p>
1.1 cvs 5691: The visibility parameter is used to control which elements should or should
5692: not be displayed, based on context. An element can have different
5693: visibilities in different views. If an element's visibility is zero for a
5694: view, that element is not displayed in that view and does not occupy any space
1.18 cvs 5695: (its extents are zero).</p>
5696: <p>
1.1 cvs 5697: Visibility takes non-negative integer values (positive or zero). If values
5698: greater than 1 are used, they allow the user to choose a degree of visibility
5699: and, thus, to see only those boxes whose visibility parameter exceeds a
5700: certain threshold. This gives the user control over the granularity of the
1.18 cvs 5701: displayed pictures.</p>
5702: <p>
1.1 cvs 5703: The visibility parameter can be defined as a constant or by inheritance. If
5704: defined by inheritance, it cannot be based on the value of the next or
1.18 cvs 5705: previous box. Visibility can only be inherited from above.</p>
5706: <p>
1.1 cvs 5707: If it is a numeric attribute's presentation rule, the visibility can be
5708: specified by the attribute's name, in which case the value of the attribute is
1.18 cvs 5709: used.</p>
5710: <pre> 'Visibility' ':' NumberInherit
1.1 cvs 5711: NumberInherit = Integer / AttrID / Inheritance .
1.18 cvs 5712: Integer = NUMBER .</pre>
5713: <blockquote class="example">
5714: <p>
5715: <strong>Example:</strong></p>
5716: <p>
5717: Suppose that only <tt>Formula</tt> elements should be displayed in the
5718: <tt>MathView</tt> view. Then, the default rules should include:</p>
5719: <pre>DEFAULT
5720: IN MathView Visibility:0;</pre>
5721: <p>
5722: which makes all elements invisible in the <tt>MathView</tt> view. However,
5723: the <tt>Formula</tt> element also has a <tt>Visibility</tt> rule:</p>
5724: <pre>Formula :
5725: IN MathView Visibility:5;</pre>
5726: <p>
5727: which makes formulas, and only formulas, visible.</p>
5728: </blockquote>
5729: </div>
1.1 cvs 5730:
1.18 cvs 5731: <div class="subsection">
1.1 cvs 5732:
1.18 cvs 5733: <h3><a name="sectc4225">Character style parameters</a></h3>
5734: <p>
1.1 cvs 5735: Four parameters are used to determine which characters are used to display
1.18 cvs 5736: text. They are size, font, style, and underlining.</p>
1.1 cvs 5737:
1.18 cvs 5738: <div class="subsubsection">
1.1 cvs 5739:
1.18 cvs 5740: <h4><a name="sectd42251">Character size</a></h4>
5741: <p>
1.1 cvs 5742: The size parameter has two effects. First, it is used to specify the actual
1.18 cvs 5743: size and distance units for boxes defined in <a href="#sectc4217">relative
5744: units</a>. Second, it defines the size of the characters contained in the
5745: box.</p>
5746: <p>
1.1 cvs 5747: As a distance or length, the size can be expressed in abstract or absolute
5748: units. It can also be inherited. If it is not inherited, it is expressed
1.18 cvs 5749: simply as an integer followed by the <tt>pt</tt> keyword, which indicates that
5750: the size is expressed in typographer's points. The absence of the <tt>pt</tt>
1.1 cvs 5751: keyword indicates that it is in abstract units in which the value 1 represents
5752: the smallest size while the value 16 is the largest size. The relationship
5753: between these abstract sizes and the real character sizes is controlled by a
5754: table which can be modified statically or even dynamically during the
1.18 cvs 5755: execution of the Thot editor.</p>
5756: <p>
1.22 cvs 5757: If the <tt>Size</tt> rule is a numeric attribute's presentation rule, the
5758: value of the size parameter can be specified by the attribute's name, in
5759: which case the value of the attribute is used.</p>
1.18 cvs 5760: <p>
5761: <strong>Note:</strong> the only unit available for defining an absolute size
5762: is the typographer's point. Centimeters and inches may not be used.</p>
5763: <p>
1.1 cvs 5764: If the size is inherited, the rule must specify the relative from which to
1.22 cvs 5765: inherit and any percentage or difference from that relative's value.
1.25 cvs 5766: A percentage is indicated by a <tt>*</tt> followed by the value of the
1.22 cvs 5767: percentage and a <tt>%</tt>.
5768: A difference can be expressed in either typographer's points or in abstract
5769: units and the maximum or minimum size can be specified, but without
5770: specifying the unit: it is the same as was specified for the difference.</p>
5771: <p>
5772: In a numeric attribute's presentation rule, the difference in size or the
5773: percentage can be indicated by the attribute's name instead of the numeric
5774: value, which means that the attribute's value should be used as the difference
5775: or percentage. The attribute can also be used as the minimum or maximum size
5776: for a difference.</p>
5777: <pre> 'Size' ':' SizeInherit
5778: SizeInherit = SizeAttr [ 'pt' ] /
5779: Kinship InheritedSize .
5780: InheritedSize ='+' SizeAttr [ 'pt' ]
5781: [ 'Max' MaxSizeAttr ] /
5782: '-' SizeAttr [ 'pt' ]
5783: [ 'Min' MinSizeAttr ] /
5784: '*' PercentSizeAttr '%' /
5785: '=' .
5786: SizeAttr = Size / AttrID .
5787: Size = NUMBER .
5788: MaxSizeAttr = MaxSize / AttrID .
5789: MaxSize = NUMBER .
5790: MinSizeAttr = MinSize / AttrID .
5791: MinSize = NUMBER .
5792: PercentSizeAttr = PercentSize / AttrID .
5793: PercentSize = NUMBER .</pre>
1.18 cvs 5794: <blockquote class="example">
5795: <p>
5796: <strong>Example:</strong></p>
5797: <p>
5798: The rule</p>
5799: <pre>Size : Enclosing - 2 pt Min 7;</pre>
5800: <p>
5801: states that the character size is 2 points less than that of the enclosing
5802: box, but that it may not be less than 7 points, whatever the enclosing box's
5803: value.</p>
5804: <p>
1.1 cvs 5805: The following rules make the text of a report be displayed with medium-sized
5806: characters (for example, size 5), while the title is displayed with larger
1.18 cvs 5807: characters and the summary is displayed with smaller characters:</p>
5808: <pre>Report :
1.1 cvs 5809: Size : 5;
5810: Title :
5811: Size : Enclosing + 2;
5812: Summary :
1.18 cvs 5813: Size : Enclosing - 1;</pre>
5814: <p>
5815: Thus, the character sizes in the entire document can be changed by changing
5816: the size parameter of the Report element, while preserving the relationships
5817: between the sizes of the different elements.</p>
5818: </blockquote>
5819: </div>
5820:
5821: <div class="subsubsection">
5822:
5823: <h4><a name="sectd42252">Font and character style</a></h4>
5824: <p>
5825: The <tt>Font</tt> rule determines the font family to be used to display the
5826: characters contained in the box, while the <tt>Style</tt> rule determines
1.23 cvs 5827: their style and the <tt>Weight</tt> rule determines their weight. Thot
5828: recognizes three character fonts (Times, Helvetica, and Courier), three
5829: styles: Roman, Italics, and Oblique, and two weights: Normal and Bold.</p>
5830: <p>
5831: The font family, style and weight can be specified by a named constant or
5832: can be inherited. For the name of the font family only the first character
5833: is used.</p>
5834: <p>
5835: Only identical inheritance is allowed: the box takes the same font, style or
5836: weight as the box from which it inherits. This is indicated by an equals
5837: sign after the kinship specification.</p>
5838: <pre> 'Font' ':' NameInherit /
5839: 'Style' ':' StyleInherit /
5840: 'Weight' ':' WeightInherit /
5841:
5842: NameInherit = Kinship '=' / FontName .
5843: FontName = NAME .
5844: StyleInherit = Kinship '=' /
5845: 'Roman' / 'Italics' / 'Oblique' .
5846: WeightInherit = Kinship '=' /
5847: 'Normal' / 'Bold' .</pre>
1.18 cvs 5848: <blockquote class="example">
5849: <p>
5850: <strong>Example:</strong></p>
5851: <p>
1.3 cvs 5852: To specify that the summary uses the font family of the rest of the document,
1.18 cvs 5853: but in the italic style, the following rules are used:</p>
5854: <pre>Summary :
1.1 cvs 5855: BEGIN
5856: Font : Enclosing =;
5857: Style : Italics;
1.18 cvs 5858: END;</pre>
5859: </blockquote>
5860: </div>
5861:
5862: <div class="subsubsection">
5863:
5864: <h4><a name="sectd42253">Underlining</a></h4>
5865: <p>
5866: The <tt>Underline</tt> rule is used to specify if the characters contained in
1.1 cvs 5867: a box should have lines drawn on or near them. There are four underlining
1.18 cvs 5868: styles: <tt>Underlined</tt>, <tt>Overlined</tt>, <tt>CrossedOut</tt>, and
5869: <tt>NoUnderline</tt>. The <tt>Thickness</tt> rule specifies the thickness of
5870: the line, <tt>Thin</tt> or <tt>Thick</tt>.</p>
5871: <p>
1.1 cvs 5872: As with font family and style, only identical inheritance is allowed: the box
5873: has the same underlining type as the box from which it inherits the value.
1.18 cvs 5874: This is indicated by an equals sign after the kinship specification.</p>
5875: <pre> 'Underline' ':' UnderLineInherit /
1.1 cvs 5876: 'Thickness' ':' ThicknessInherit /
5877:
5878: UnderLineInherit = Kinship '=' / 'NoUnderline' /
5879: 'Underlined' /
5880: 'Overlined' / 'CrossedOut' .
1.18 cvs 5881: ThicknessInherit = Kinship '=' / 'Thick' / 'Thin' .</pre>
5882: </div>
5883: </div>
5884:
5885: <div class="subsection">
5886:
5887: <h3><a name="sectc4226">Stacking order</a></h3>
5888: <p>
5889: The <tt>Depth</tt> rule is used to define the stacking order of terminal boxes
1.1 cvs 5890: when multiple boxes at least partially overlap. This rule defines how the
5891: depth parameter, which is zero or a positive integer, is calculated. The
5892: depth parameter has a value for all boxes. For terminal boxes in the
5893: structure and for presentation boxes, the depth value is used during display
5894: and printing: the boxes with the lowest value overlap those with higher
5895: depths. For non-terminal boxes, the depth is not interpreted during display,
1.18 cvs 5896: but it is used to calculate the depth of terminal boxes by inheritance.</p>
5897: <p>
5898: Like most other rules, the depth rule is defined in the <a
5899: href="#sectc427">default rules</a> of each presentation schema. Thus, there
5900: is always a depth value, even when it is not necessary because there is no
5901: overlapping. To avoid useless operations, a zero value can be given to the
5902: depth parameter, which signifies that overlapping is never a problem.</p>
5903: <p>
5904: The depth rule has the same form as the <a href="#sectc4224">visibility
5905: rule</a>. It can be defined by inheritance or by a constant numeric value.
5906: When the rule is attached to a numeric attribute, it can take the value of
5907: that attribute.</p>
5908: <pre> 'Depth' ':' NumberInherit</pre>
5909: <blockquote class="example">
5910: <p>
5911: <strong>Example:</strong></p>
5912: <p>
1.3 cvs 5913: For a purely textual document, in which overlapping never poses a problem, a
1.18 cvs 5914: single default <tt>Depth</tt> rule in the presentation schema is
5915: sufficient:</p>
5916: <pre>DEFAULT
1.1 cvs 5917: Depth : 0;
1.18 cvs 5918: ...</pre>
5919: <p>
1.1 cvs 5920: To make the text of examples appear on a light blue background, a presentation
1.18 cvs 5921: box is defined:</p>
5922: <pre>BOXES
1.1 cvs 5923: BlueBG :
5924: BEGIN
5925: Content : Graphics 'R';
5926: Background : LightBlue3;
5927: FillPattern: backgroundcolor;
5928: Depth : 2;
5929: ...
1.18 cvs 5930: END;</pre>
5931: <p>
5932: and is created by the <tt>Example</tt> element, which has the rules:</p>
5933: <pre>RULES
1.1 cvs 5934: Example :
5935: BEGIN
5936: CreateFirst (BlueBG);
5937: Depth : 1;
5938: ...
1.18 cvs 5939: END;</pre>
5940: <p>
5941: In this way, the text of an example (if it inherits its depth from its
5942: ancestor) will be superimposed on a light blue background, and not the
5943: reverse).</p>
5944: </blockquote>
5945: </div>
5946:
5947: <div class="subsection">
5948:
5949: <h3><a name="sectc4227">Line style</a></h3>
5950: <p>
5951: The <tt>LineStyle</tt> rule determines the style of line which should be used
5952: to draw all the elements contained in the box and the box itself, if it has a
5953: <a href="#sectc4230a"><tt>ShowBox</tt> rule</a>. The line style can be
5954: indicated by a name (<tt>Solid</tt>, <tt>Dashed</tt>, <tt>Dotted</tt>) or it
1.13 cvs 5955: can be inherited. All elements of the graphic base type are affected by this
1.1 cvs 5956: rule, but it can be attached to any box and transmitted by inheritance to the
1.18 cvs 5957: graphic elements. The border of elements having a <a
5958: href="#sectc4230a"><tt>ShowBox</tt> rule</a> is drawn according to the line
5959: style specified by this rule.</p>
5960: <p>
1.1 cvs 5961: Only identical inheritance is allowed: the box takes the same line style as
5962: the box from which it inherits. This is indicated by an equals sign after the
1.18 cvs 5963: kinship specification.</p>
5964: <pre> 'LineStyle' ':' LineStyleInherit
1.1 cvs 5965: LineStyleInherit = Kinship '=' /
1.18 cvs 5966: 'Solid' / 'Dashed' / 'Dotted' .</pre>
5967: <blockquote class="example">
5968: <p>
5969: <strong>Example:</strong></p>
5970: <p>
1.3 cvs 5971: To specify that, in Figures, the graphical parts should be drawn in solid
1.18 cvs 5972: lines, the Figure element is given a rule using the <tt>Solid</tt> name:</p>
5973: <pre>Figure :
5974: LineStyle : Solid;</pre>
5975: <p>
5976: and the elements composing figures are given an inheritance rule:</p>
5977: <pre> LineStyle : Enclosing =;</pre>
5978: </blockquote>
5979: </div>
5980:
5981: <div class="subsection">
5982:
5983: <h3><a name="sectc4228">Line thickness</a></h3>
5984: <p>
5985: The <tt>LineWeight</tt> rule determines the thickness of the lines of all
1.1 cvs 5986: graphical elements which appear in the box, no matter what their line style.
5987: Line thickness can be specified by a constant value or by inheritance. A
5988: constant value is a positive number followed by an optional unit specification
1.18 cvs 5989: (which is absent when using relative units). All available <a
5990: href="#sectc4217">distance units</a> can be used. Line thickness is expressed
5991: in the same way as <a href="#sectd42221">line spacing</a>.</p>
5992: <pre> 'LineWeight' ':' DistOrInherit</pre>
5993: <p>
5994: All elements of the graphic base type are affected by this rule, but it can be
5995: attached to any box and transmitted by inheritance to the graphic elements.
5996: The border of element having a <a href="#sectc4230a"><tt>ShowBox</tt> rule</a>
5997: is also drawn according to the thickness specified by this rule.</p>
5998: <blockquote class="example">
5999: <p>
6000: <strong>Example:</strong></p>
6001: <p>
6002: To specify that, in Figures, the graphical parts should be drawn with lines
6003: 0.3 pt thick, the Figure element is given this rule:</p>
6004: <pre>Figure :
6005: LineWeight : 0.3 pt;</pre>
6006: <p>
6007: and the elements composing figures are given an inheritance rule:</p>
6008: <pre> LineWeight : Enclosing =;</pre>
6009: </blockquote>
6010: </div>
6011:
6012: <div class="subsection">
6013:
6014: <h3><a name="sectc4229">Fill pattern</a></h3>
6015: <p>
6016: The <tt>FillPattern</tt> rule determines the pattern used to fill closed
1.1 cvs 6017: graphical elements (circles, rectangles, etc.) which appear in the box. This
1.18 cvs 6018: rule also specifies the pattern used to fill the box associated with elements
6019: having a <a href="#sectc4230a"><tt>ShowBox</tt> rule</a><a>. This pattern can
6020: be indicated by a named constant or by inheritance. The named constant
6021: identifies one of the patterns available in Thot. The names of the available
6022: patterns are: nopattern, foregroundcolor, backgroundcolor, gray1, gray2,
6023: gray3, gray4, gray5, gray6, gray7, horiz1, horiz2, horiz3, vert1, vert2,
6024: vert3, left1, left2, left3, right1, right2, right3, square1, square2, square3,
6025: lozenge, brick, tile, sea, basket.</a></p>
6026: <p>
6027: Like the other rules peculiar to graphics, <tt>LineStyle</tt> and
6028: <tt>LineWeight</tt>, only elements of the graphic base type are affected by
6029: the <tt>FillPattern</tt> rule, but the rule can be attached to any box and
1.1 cvs 6030: transmitted by inheritance to the graphic elements. As with the other rules
1.18 cvs 6031: specific to graphics, only identical inheritance is allowed.</p>
6032: <p>
6033: The <tt>FillPattern</tt> rule can also be used to determine whether or not
1.12 cvs 6034: text characters, symbols and pictures should be colored. For these element
6035: types (text, symbols, and pictures), the only valid values are
1.18 cvs 6036: <tt>nopattern</tt>, <tt>foregroundcolor</tt>, and <tt>backgroundcolor</tt>.
6037: When <tt>FillPattern</tt> has the value <tt>backgroundcolor</tt>, text
6038: characters, symbols, and bitmaps are given the color specified by the <a
6039: href="#sectc4230"><tt>Background</tt> rule</a> which applies to these
6040: elements. When <tt>FillPattern</tt> has the value <tt>foregroundcolor</tt>,
6041: these same elements are given the color specified by the <a
6042: href="#sectc4230"><tt>Foreground</tt> rule</a> which applies to these
6043: elements. In all other case, text characters are not colored.</p>
6044: <pre> 'FillPattern' ':' NameInherit</pre>
6045: <blockquote class="example">
6046: <p>
6047: <strong>Example:</strong></p>
6048: <p>
1.3 cvs 6049: To specify that, in Figures, the closed graphical elements should be filled
6050: with a pattern resembling a brick wall, the Figure element is given this
1.18 cvs 6051: rule:</p>
6052: <pre>Figure :
6053: FillPattern : brick;</pre>
6054: <p>
6055: and the elements composing figures are given an inheritance rule:</p>
6056: <pre> FillPattern : Enclosing =;</pre>
6057: </blockquote>
6058: </div>
6059:
6060: <div class="subsection">
6061:
6062: <h3><a name="sectc4230">Colors</a></h3>
6063: <p>
6064: The <tt>Foreground</tt> and <tt>Background</tt> rules determine the foreground
1.13 cvs 6065: and background colors of the base elements which appear in the box. They also
1.18 cvs 6066: control the color of boxes associated with elements having a <a
6067: href="#sectc4230a"><tt>ShowBox</tt> rule</a>. These colors can be specified
6068: with a named constant or by inheritance. The named constants specify one of
6069: the available colors in Thot. The available color names can be found in the
6070: file <tt>thot.color</tt>.</p>
6071: <p>
6072: The color rules affect the same way all base elements and elements having a <a
6073: href="#sectc4230a"><tt>ShowBox</tt> rule</a>, no matter what their type (text,
6074: graphics, pictures, symbols). The color rules can be associated with any box
6075: and can be transmitted by inheritance to the base elements or the elements
6076: having a <a href="#sectc4230a"><tt>ShowBox</tt> rule</a>. Like the preceding
6077: rules, only inheritance of the same value is allowed.</p>
6078: <pre> 'Foreground' ':' NameInherit
6079: 'Background' ':' NameInherit</pre>
6080: <p>
6081: <strong>Note:</strong> text colors only appear for text elements whose <a
6082: href="#sectc4229">fill pattern</a> does not prevent the use of color.</p>
6083: <blockquote class="example">
6084: <p>
6085: <strong>Example:</strong></p>
6086: <p>
1.3 cvs 6087: To specify that, in Figures, everything must be drawn in blue on a background
1.18 cvs 6088: of yellow, the Figure element is given these rules:</p>
6089: <pre>Figure :
1.1 cvs 6090: BEGIN
6091: Foreground : Blue;
6092: Background : Yellow;
6093: Fillpattern : backgroundcolor;
1.18 cvs 6094: END;</pre>
6095: <p>
6096: and the elements composing figures are given inheritance rules:</p>
6097: <pre> Foreground : Enclosing =;
1.1 cvs 6098: Background : Enclosing =;
1.18 cvs 6099: FillPattern : Enclosing =;</pre>
6100: </blockquote>
6101: </div>
6102:
6103: <div class="subsection">
6104:
6105: <h3><a name="sectc4230a">Background color and border</a></h3>
6106: <p>
6107: Boxes associated with structural elements are normally not visible, but it is
6108: possible to draw their border and/or to paint their area when it is needed.
6109: This is achieved by associating the <tt>ShowBox</tt> rule with the concerned
1.13 cvs 6110: element. This rule has no parameter and no value. It is simply written
1.18 cvs 6111: <tt>Showbox;</tt>. It is not inherited nor transmitted to any other element.
6112: It applies only to the element with which it is associated.</p>
6113: <pre> 'ShowBox'</pre>
6114: <p>
6115: When an element has a <tt>ShowBox</tt> rule, the border is drawn only if the
6116: <tt>LineWeight</tt> rule that applies to that element has a non-zero value
6117: (this value can be inherited). The color, style and thickness of the border
6118: are defined by the <tt>Foreground</tt>, <tt>LineStyle</tt>, and
6119: <tt>LineWeight</tt> rules that apply to the element.</p>
6120: <p>
6121: When an element has a <tt>ShowBox</tt> rule, the background of this element is
6122: paint only if the value of the <tt>FillPattern</tt> rule that applies to that
6123: element is not <tt>nopattern</tt>. The pattern and color(s) of the background
6124: are defined by the <tt>FillPattern</tt>, <tt>Background</tt>, and
6125: <tt>Foreground</tt> rules that apply to the element.</p>
6126: </div>
6127:
6128: <div class="subsection">
6129:
6130: <h3><a name="sectc4230b">Background pictures</a></h3>
6131: <p>
6132: The <tt>BackgroundPicture</tt> rule allows to display a picture as the
1.13 cvs 6133: background of an element. It has a single parameter, the file name of the
1.18 cvs 6134: picture. This is a string delimited by single quotes. If the first character
6135: in this string is '/', it is considered as an absolute path, otherwise the
6136: file is searched for along the schema directory path. This file may contain a
6137: picture in any format accepted by Thot (xbm, xpm, gif, jpeg, png, etc.)</p>
6138: <p>
6139: The <tt>BackgroundPicture</tt> and <tt>PictureMode</tt> rules apply only to
1.13 cvs 6140: the element with which they are associated. They are not inherited nor
1.18 cvs 6141: transmitted to children elements.</p>
6142: <p>
1.13 cvs 6143: The background picture has not always the same size as the element's box.
6144: There are diffrent ways to fill the element box with the picture. This is
1.18 cvs 6145: specified by the <tt>PictureMode</tt> rule, which should be associated to the
6146: same element. This rule may take one of the following values:</p>
6147: <dl>
6148: <dt><tt>NormalSize</tt></dt>
6149: <dd>
6150: The picture is centered in the box, and clipped if it is too large.
6151: </dd>
6152: <dt><tt>Scale</tt></dt>
6153: <dd>
6154: The picture is zoomed to fit the box size.
6155: </dd>
6156: <dt><tt>RepeatX</tt></dt>
6157: <dd>
6158: The picture is repeated horizontally to fit the box width.
6159: </dd>
6160: <dt><tt>RepeatY</tt></dt>
6161: <dd>
6162: The picture is repeated vertically to fit the box height.
6163: </dd>
6164: <dt><tt>RepeatXY</tt></dt>
6165: <dd>
6166: The picture is repeated both horizontally and vertically to fill the box.
6167: </dd>
6168: </dl>
6169: <p>
6170: If an element has a <tt>BackgroundPicture</tt> rule and no
6171: <tt>PictureMode</tt> rule, the <tt>NormalSize</tt> value is assumed.</p>
6172: <pre> 'BackgroundPicture' ':' FileName /
1.13 cvs 6173: 'PictureMode' ':' PictMode .
6174:
6175: FileName = STRING .
1.18 cvs 6176: PictMode = 'NormalSize' / 'Scale' / 'RepeatXY' / 'RepeatX' / 'RepeatY' .</pre>
6177: <p>
6178: The <tt>BackgroundPicture</tt> and <tt>PictureMode</tt> rules apply only to
1.13 cvs 6179: the element with which they are associated. They are not inherited nor
1.18 cvs 6180: transmitted to children elements.</p>
6181: </div>
1.13 cvs 6182:
1.18 cvs 6183: <div class="subsection">
1.1 cvs 6184:
1.18 cvs 6185: <h3><a name="sectc4231">Presentation box content</a></h3>
6186: <p>
6187: The <tt>Content</tt> rule applies to presentation boxes. It indicates the
1.1 cvs 6188: content given to a box. This content is either a variable's value or a
1.18 cvs 6189: constant value. In the special case of <a href="#sectc4233">header or footer
6190: boxes</a>, the content can also be a structured element type.</p>
6191: <p>
1.1 cvs 6192: If the content is a constant, it can be specified, as in a variable
1.18 cvs 6193: declaration, either by the name of a constant declared in the <tt>CONST</tt>
1.1 cvs 6194: section or by direct specification of the type and value of the box's
1.18 cvs 6195: content.</p>
6196: <p>
1.1 cvs 6197: Similarly, if it is a variable, the name of a variable declared in
1.18 cvs 6198: <tt>VAR</tt> section can be given or the variable may be defined within
6199: parentheses. The content inside the parentheses has the same syntax as a <a
6200: href="#sectc426">variable declaration</a>.</p>
6201: <p>
1.1 cvs 6202: When the content is a structured element type, the name of the element type is
6203: given after the colon. In this case, the box's content is all elements of
6204: the named type which are designated by references which are part of the page
1.18 cvs 6205: on which the header or footer with this <tt>Content</tt> rule appears. Only
6206: associated elements can appear in a <tt>Content</tt> rule and the structure
1.1 cvs 6207: must provide references to these elements. Moreover, the box whose content
6208: they are must be a header or footer box generated by a page box of the primary
1.18 cvs 6209: view.</p>
6210: <pre> 'Content' ':' VarConst
1.1 cvs 6211: VarConst = ConstID / ConstType ConstValue /
6212: VarID / '(' FunctionSeq ')' /
1.18 cvs 6213: ElemID .</pre>
6214: <p>
6215: A presentation box can have only one <tt>Content</tt> rule, which means that
1.1 cvs 6216: the content of a presentation box cannot vary from view to view. However, such
6217: an effect can be achieved by creating several presentation boxes, each with
1.18 cvs 6218: different content and visible in different views.</p>
6219: <p>
6220: The <tt>Content</tt> rule also applies to elements defined as references in
1.1 cvs 6221: the structure schema. In this case, the content defined by the rule must be
6222: a constant. It is this content which appears on the screen or paper to
6223: represent references of the type to which the rule applies. A reference can
1.18 cvs 6224: have a <tt>Content</tt> rule or a <a href="#sectc4234"><tt>Copy</tt> rule</a>
1.1 cvs 6225: for each view. If neither of these rules appears, the reference is displayed
1.18 cvs 6226: as <tt>[*]</tt>, which is equivalent to the rule:</p>
6227: <pre> Content: Text '[*]';</pre>
6228: <blockquote class="example">
6229: <p>
6230: <strong>Example:</strong></p>
6231: <p>
1.3 cvs 6232: The content of the presentation box created to make the chapter number and
1.18 cvs 6233: section number appear before each section title can be defined by:</p>
6234: <pre>BOXES
1.1 cvs 6235: SectionNumBox :
6236: BEGIN
6237: Content : NumSection;
6238: ...
1.18 cvs 6239: END;</pre>
6240: <p>
6241: if the <tt>NumSection</tt> variable has been defined in the variable
6242: definition section of the presentation schema. Otherwise the <tt>Content</tt>
6243: would be written:</p>
6244: <pre>BOXES
1.1 cvs 6245: SectionNumBox :
6246: BEGIN
6247: Content : (VALUE (ChapterCtr, Roman) TEXT '.'
6248: VALUE (SectionCtr, Arabic));
6249: ...
1.18 cvs 6250: END;</pre>
6251: <p>
6252: To specify that a page footer should contain all elements of the <tt>Note</tt>
6253: type are referred to in the page, the following rule is written:</p>
6254: <pre>BOXES
1.1 cvs 6255: NotesFooterBox :
6256: BEGIN
6257: Content : Note;
6258: ...
1.18 cvs 6259: END;</pre>
6260: <p>
6261: <tt>Note</tt> is defined as an associated element in the structure schema and
6262: NotesFooterBox is created by a page box of the primary view.</p>
6263: </blockquote>
6264: </div>
1.1 cvs 6265:
1.18 cvs 6266: <div class="subsection">
1.1 cvs 6267:
1.18 cvs 6268: <h3><a name="sectc4232">Presentation box creation</a></h3>
6269: <p>
1.1 cvs 6270: A creation rule specifies that a presentation box should be created when an
1.18 cvs 6271: element of the type to which the rule is attached appears in the document.</p>
6272: <p>
1.1 cvs 6273: A keyword specifies the position, relative to the creating box, at which the
1.18 cvs 6274: created box will be placed in the structure:</p>
6275: <dl>
6276: <dt><tt>CreateFirst</tt></dt>
6277: <dd>
6278: specifies that the box should be created as the first box of the next lower
1.2 cvs 6279: level, before any already existing boxes, and only if the beginning of the
1.1 cvs 6280: creating element is visible;
1.18 cvs 6281: </dd>
6282: <dt><tt>CreateLast</tt></dt>
6283: <dd>
6284: specifies that the box should be created as the last box of the next lower
6285: level, after any existing boxes, and only if the end of the creating element
6286: is visible;
6287: </dd>
6288: <dt><tt>CreateBefore</tt></dt>
6289: <dd>
6290: specifies that the box should be created before the creating box, on the same
6291: level as the creating box, and only if the beginning of the creating element
6292: is visible;
6293: </dd>
6294: <dt><tt>CreateAfter</tt></dt>
6295: <dd>
6296: specifies that the box should be created after the creating box, on the same
6297: level as the creating box, and only if the beginning of the creating element
6298: is visible;
6299: </dd>
6300: <dt><tt>CreateEnclosing</tt></dt>
6301: <dd>
6302: specifies that the box should be created at the upper level relatively to the
6303: creating box, and that it must contain that creating box and all presentation
6304: boxes created by the same creating box.
6305: </dd>
6306: </dl>
6307: <p>
6308: This keyword can be followed by the <tt>Repeated</tt> keyword to indicate that
1.1 cvs 6309: the box must be created for each part of the creating element. These parts
6310: result from the division of the element by page breaks or column changes. If
1.18 cvs 6311: the <tt>Repeated</tt> keyword is missing, the box is only created for the
6312: first part of the creating element (<tt>CreateFirst</tt> and
6313: <tt>CreateBefore</tt> rules) or for the last part (<tt>CreateLast</tt> and
6314: <tt>CreateAfter</tt> rules).</p>
6315: <p>
1.1 cvs 6316: The type of presentation to be created is specified at the end of the rule
1.18 cvs 6317: between parentheses.</p>
6318: <p>
6319: Creation rules cannot appear in the <a href="#sectc427">default presentation
6320: rules</a>. The boxes being created should have a <tt>Content</tt> rule which
6321: indicates their <a href="#sectc4231">content</a>.</p>
6322: <p>
1.1 cvs 6323: Creation rules can only appear in the block of rules for the primary view;
6324: creation is provoked by a document element for all views. However, for each
6325: view, the presentation box is only created if the creating element is itself a
6326: box in the view. Moreover, the visibility parameter of the presentation box
6327: can be adjusted to control the creation of the box on a view-by-view
1.18 cvs 6328: basis.</p>
6329: <pre> Creation '(' BoxID ')'
1.1 cvs 6330: Creation = Create [ 'Repeated' ] .
6331: Create ='CreateFirst' / 'CreateLast' /
6332: 'CreateBefore' / 'CreateAfter' /
1.18 cvs 6333: 'CreateEnclosing' .</pre>
6334: <blockquote class="example">
6335: <p>
6336: <strong>Example:</strong></p>
6337: <p>
1.3 cvs 6338: Let us define an object type, called Table, which is composed of a sequence of
6339: columns, all having the same fixed width, where the columns are separated by
1.18 cvs 6340: vertical lines. There is a line to the left of the first column and one to
6341: the right of the last. Each column has a variable number of cells, placed one
6342: on top of the other and separated by horizontal lines. There are no
6343: horizontal lines above the first cell or below the last cell. The text
6344: contained in each cell is broken into lines and these lines are centered
6345: horizontally in the cell. The logical structure of this object is defined
6346: by:</p>
6347: <pre>Table = LIST OF (Column);
6348: Column = LIST OF (Cell = Text);</pre>
6349:
6350: <div class="figure">
6351: <hr>
1.19 cvs 6352:
1.18 cvs 6353: <pre>| | | |
1.1 cvs 6354: | xx xxxx xxxx |x xxxx xxx xxxxx| x xxx x xxx |
6355: | xxx xxx xxxx x | x xx x xxx | xxxxx xxxx xx |
6356: | xxxxx xxxx |----------------| xxx xxxxx x |
6357: | xxxxx xxx xxxx | xxxx xx xx xxx | xx xx |
6358: | xxx xxxx x xxx | xxxx x xxx x |---------------|
6359: |----------------| xxx xxxx xxxxx | xxxxx xxxxx |
6360: | xxx xxx xxxxxx |----------------| xxx xxxx xxxx |
6361: | xxxx xxxx xx | xxxx xx x xx | xxx xx x xx |
6362: |----------------| xxx xxxxx xxxx | xxxx xxxx xxx |
6363: | xxxxx xxx xxxx | xxxx xx x xx | xxxxx xxx |
1.18 cvs 6364: |xxxx xx x xxxxxx| xxxx xx xxxxxx | xxxxx xxxxx |</pre>
1.19 cvs 6365: <p align="center">
1.18 cvs 6366: <em><a name="table">The design of a table</a></em></p>
6367: <hr>
1.19 cvs 6368:
1.18 cvs 6369: </div>
6370: <p>
6371: The presentation of the table should resemble the design of the above <a
6372: href="#table">figure</a>. It is defined by the following presentation schema
6373: fragment:</p>
6374: <pre>BOXES
1.1 cvs 6375: VertLine : BEGIN
6376: Width : 0.3 cm;
6377: Height : Enclosing . Height;
6378: VertPos : Top = Enclosing . Top;
6379: HorizPos : Left = Previous . Right;
6380: Content : Graphics 'v';
6381: END;
6382:
6383: HorizLine: BEGIN
6384: Width : Enclosing . Width;
6385: Height : 0.3 cm;
6386: VertPos : Top = Previous . Bottom;
6387: HorizPos : Left = Enclosing . Left;
6388: Content : Graphics 'h';
6389: END;
6390:
6391: RULES
1.6 cvs 6392: Column : BEGIN
6393: CreateBefore (VertLine);
6394: IF LAST CreateAfter (VertLine);
6395: Width : 2.8 cm;
6396: Height : Enclosed . Height;
6397: VertPos : Top = Enclosing . Top;
6398: HorizPos : Left = Previous . Right;
6399: END;
6400:
6401: Cell : BEGIN
6402: IF NOT FIRST CreateBefore (HorizLine);
6403: Width : Enclosing . Width;
6404: Height : Enclosed . Height;
6405: VertPos : Top = Previous . Bottom;
6406: HorizPos : Left = Enclosing . Left;
6407: Line;
6408: Adjust : VMiddle;
1.18 cvs 6409: END;</pre>
6410: <p>
1.1 cvs 6411: It is useful to note that the horizontal position rule of the first vertical
6412: line will not be applied, since there is no preceding box. In this case, the
1.18 cvs 6413: box is simply placed on the left side of the enclosing box.</p>
6414: </blockquote>
6415: </div>
6416:
6417: <div class="subsection">
6418:
6419: <h3><a name="sectc4233">Page layout</a></h3>
6420: <p>
6421: The page models specified in the <tt>Page</tt> rule are defined by boxes
6422: declared in the <tt>BOXES</tt> section of the presentation schema. Pages are
1.1 cvs 6423: not described as frames which will be filled by the document's text, but as
6424: element are inserted in the flow of the document and which mark the page
6425: breaks. Each of these page break elements contains presentation boxes which
6426: represent the footer boxes of a page followed by header boxes of the next
6427: page. The page box itself is the simple line which separates two pages on the
6428: screen. Both the footer and header boxes placed themselves with respect to
6429: this page box, with the footer being placed above it and the header boxes
1.18 cvs 6430: being placed above it.</p>
6431: <p>
1.1 cvs 6432: The boxes created by a page box are headers and footers and can only place
6433: themselves vertically with respect to the page box itself (which is in fact
6434: the separation between two pages). Besides, it is their vertical position
6435: rule which determines whether they are header or footer boxes. Header and
6436: footer boxes must have an explicit vertical position rule (they must not use
1.18 cvs 6437: the default rule).</p>
6438: <p>
1.1 cvs 6439: Footer boxes must have an absolute height or inherit the height of their
1.18 cvs 6440: contents:</p>
6441: <pre>Height : Enclosed . Height;</pre>
6442: <p>
1.1 cvs 6443: A page box must have height and width rules and these two rules must be
6444: specified with constant values, expressed in centimeters, inches, or
6445: typographer's points. These two rules are interpreted in a special way for
6446: page boxes: they determine the width of the page and the vertical distance
6447: between two page separators, which is the height of the page and its header
1.18 cvs 6448: and footer together.</p>
6449: <p>
1.1 cvs 6450: A page box should also have vertical and horizontal position rules and these
6451: two rules should specify the position on the sheet of paper of the rectangle
6452: enclosing the page's contents. These two rules must position the upper left
6453: corner of the enclosing rectangle in relation to the upper left corner of the
6454: sheet of paper, considered to be the enclosing element. In both rules,
1.18 cvs 6455: distances must be expressed in fixed units: centimeters (<tt>cm</tt>), inches
6456: (<tt>in</tt>), or typographer's points (<tt>pt</tt>). Thus, rules similar to
6457: the following should be found in the rules for a page box:</p>
6458: <pre>BOXES
1.1 cvs 6459: ThePage :
6460: BEGIN
6461: VertPos : Top = Enclosing . Top + 3 cm;
6462: HorizPos : Left = Enclosing . Left + 2.5 cm;
6463: Width : 16 cm;
6464: Height : 22.5 cm;
1.18 cvs 6465: END;</pre>
6466: <p>
1.1 cvs 6467: When a document must be page broken, the page models to be constructed are
1.18 cvs 6468: defined in the <tt>BOXES</tt> section of the presentation schema by declaring
6469: page boxes and header and footer boxes. Also, the <tt>Page</tt> rule is used
1.1 cvs 6470: to specify to which parts of the document and to which views each model should
1.18 cvs 6471: be applied.</p>
6472: <p>
6473: The <tt>Page</tt> rule has only one parameter, given between parentheses after
6474: the <tt>Page</tt> keyword. This parameter is the name of the box which must
6475: serve as the model for page construction. When a <tt>Page</tt> rule is
1.1 cvs 6476: attached to an element type, each time such an element appears in a document,
6477: a page break takes place and the page model indicated in the rule is applied
6478: to all following pages, until reaching the next element which has a
1.18 cvs 6479: <tt>Page</tt> rule.</p>
6480: <p>
6481: The <tt>Page</tt> rule applies to only one view; if it appears in the primary
6482: view's block of rules, a <tt>Page</tt> rule applies only to that view. Thus,
1.1 cvs 6483: different page models can be defined for the full document and for its table
6484: of contents, which is another view of the same document. Some views can be
6485: specified with pages, and other views of the same document can be specified
1.18 cvs 6486: without pages.</p>
6487: <pre> 'Page' '(' BoxID ')'</pre>
6488: </div>
6489:
6490: <div class="subsection">
6491:
6492: <h3><a name="sectc4234">Box copies</a></h3>
6493: <p>
6494: The <tt>Copy</tt> rule can be used for an element which is defined as a
1.7 cvs 6495: reference in the structure schema. In this case, the rule specifies, between
1.18 cvs 6496: parenthesis, the name of the box (declared in the <tt>BOXES</tt> section)
1.1 cvs 6497: which must be produced when this reference appears in the structure of a
6498: document. The box produced is a copy (same contents, but possible different
6499: presentation) of the box type indicated by the parameter between parentheses,
6500: and which is in the element designated by the reference. The name of a box
6501: can be replaced by type name. Then what is copied is the contents of the
1.18 cvs 6502: element of this type which is inside the referenced element.</p>
6503: <p>
1.1 cvs 6504: Whether a box name or type name is given, it may be followed by the name of a
6505: structure schema between parentheses. This signifies that the box or type is
6506: defined in the indicated structure schema and not in the structure schema with
1.18 cvs 6507: which the rule's presentation schema is associated.</p>
6508: <p>
6509: The <tt>Copy</tt> rule can also be applied to a presentation box. If the
1.1 cvs 6510: presentation box was created by a reference attribute, the rule is applied as
6511: in the case of a reference element: the contents of the box having the
1.18 cvs 6512: <tt>Copy</tt> rule are based on the element designated by the reference
6513: attribute. For other presentation boxes, the <tt>Copy</tt> rule takes a type
1.1 cvs 6514: name parameter which can be followed, between parentheses, by the name of the
6515: structure schema in which the type is defined, if it is not defined in the
6516: same schema. The contents of the box which has this rule are a copy of the
6517: element of this type which is in the element creating the presentation box, or
6518: by default, the box of this type which precedes the presentation box. This
6519: last facility is used, for example, to define the running titles in headers or
1.18 cvs 6520: footers.</p>
6521: <pre> 'Copy' '(' BoxTypeToCopy ')' .
1.1 cvs 6522: BoxTypeToCopy = BoxID [ ExtStruct ] /
1.6 cvs 6523: ElemID [ ExtStruct ] .
1.18 cvs 6524: ExtStruct = '(' ElemID ')' .</pre>
6525: <p>
6526: Like the creation rules, the <tt>Copy</tt> rule cannot appear in the <a
6527: href="#sectc427">default presentation rules</a>. Moreover, this rule can only
6528: appear in the primary view's block of rules; the copy rule is applied to all
6529: views.</p>
6530: <blockquote class="example">
6531: <p>
6532: <strong>Example:</strong></p>
6533: <p>
6534: If the following definitions are in the structure schema:</p>
6535: <pre>Body = LIST OF (Chapter =
1.1 cvs 6536: BEGIN
6537: ChapterTitle = Text;
6538: ChapterBody = SectionSeq;
6539: END);
1.18 cvs 6540: RefChapter = REFERENCE (Chapter);</pre>
6541: <p>
6542: then the following presentation rules (among many other rules in the
6543: presentation schema) can be specified:</p>
6544: <pre>COUNTERS
1.1 cvs 6545: ChapterCtr : RANK OF Chapter;
6546: BOXES
6547: ChapterNumber :
6548: BEGIN
6549: Content : (VALUE (ChapterCtr, URoman));
6550: ...
6551: END;
6552: RULES
6553: Chapter :
6554: BEGIN
6555: CreateFirst (ChapterNumber);
6556: ...
6557: END;
6558: RefChapter :
6559: BEGIN
6560: Copy (ChapterNumber);
6561: ...
1.18 cvs 6562: END;</pre>
6563: <p>
1.4 cvs 6564: which makes the number of the chapter designated by the reference appear in
6565: uppercase roman numerals, in place of the reference to a chapter itself.
6566: Alternatively, the chapter title can be made to appear in place of the
1.18 cvs 6567: reference by writing this <tt>Copy</tt>rule:</p>
6568: <pre> Copy (ChapterTitle);</pre>
6569: <p>
6570: To define a header box, named <tt>RunningTitle</tt>, which contains the title
6571: of the current chapter, the box's contents are defined in this way:</p>
6572: <pre>BOXES
1.1 cvs 6573: RunningTitle :
1.18 cvs 6574: Copy (ChapterTitle);</pre>
6575: </blockquote>
6576: </div>
6577: </div>
6578: <hr>
1.19 cvs 6579:
1.18 cvs 6580: </div>
1.1 cvs 6581:
1.18 cvs 6582: <div class="chapter">
1.1 cvs 6583:
1.18 cvs 6584: <h1><a name="sect5">The T language</a></h1>
1.1 cvs 6585:
1.18 cvs 6586: <div class="section">
1.1 cvs 6587:
1.18 cvs 6588: <h2><a name="sectb51">Document translation</a></h2>
6589: <p>
1.1 cvs 6590: Because of its document model, Thot can produce documents in a high-level
1.18 cvs 6591: abstract form. This form, called the <em>canonical form</em> is specific to
1.1 cvs 6592: Thot; it is well suited to the editor's manipulations, but it does not
6593: necessarily suit other operations which might be applied to documents. Because
6594: of this, the Thot editor offers the choice of saving documents in its own form
6595: (the canonical form) or a format defined by the user. In the latter case, the
6596: Thot document is transformed by the translation program. This facility can
6597: also be used to export documents from Thot to systems using other
1.18 cvs 6598: formalisms.</p>
1.1 cvs 6599:
1.18 cvs 6600: <div class="subsection">
1.1 cvs 6601:
1.18 cvs 6602: <h3><a name="sectc511">Translation principles</a></h3>
6603: <p>
1.1 cvs 6604: Document translation allows the export of documents to other systems which do
6605: not accept Thot's canonical form. Translation can be used to export document
1.18 cvs 6606: to source-based formatters like T<sub><big>E</big></sub>X,
6607: L<sup>A</sup>T<sub><big>E</big></sub>X, and <tt>troff</tt>. It can also be
1.1 cvs 6608: used to translate documents into interchange formats like SGML or HTML. To
6609: allow the widest range of possible exports, Thot does not limit the choice of
6610: translations, but rather allows the user to define the formalisms into which
1.18 cvs 6611: documents can be translated.</p>
6612: <p>
1.1 cvs 6613: For each document or object class, a set of translation rules can be defined,
6614: specifying how the canonical form should be transformed into a given
1.18 cvs 6615: formalism. These translation rules are grouped into <em>translation
6616: schemas</em>, each schema containing the rules necessary to translate a
1.1 cvs 6617: generic logical structure (document or object structure) into a particular
6618: formalism. The same generic logical structure can have several different
6619: translation schemas, each defining translation rules for a different
1.18 cvs 6620: formalism.</p>
6621: <p>
1.1 cvs 6622: Like presentation schemas, translation schemas are generic. Thus, they apply
6623: to an entire object or document class and permit translation of all documents
1.18 cvs 6624: or objects of that class.</p>
6625: </div>
1.1 cvs 6626:
1.18 cvs 6627: <div class="subsection">
1.1 cvs 6628:
1.18 cvs 6629: <h3><a name="sectc512">Translation procedure</a></h3>
6630: <p>
1.1 cvs 6631: The translator works on the specific logical structure of the document being
6632: translated. It traverses the primary tree of this logical structure in
6633: pre-order and, at each node encountered, it applies the corresponding
6634: translation rules defined in the translation schema. Translation can be
1.18 cvs 6635: associated:</p>
6636: <ul>
6637: <li>
6638: with element types defined in the structure schema,
1.19 cvs 6639: </li>
1.18 cvs 6640: <li>
6641: with global or local attributes defined in the structure schema,
1.19 cvs 6642: </li>
1.18 cvs 6643: <li>
6644: with specific presentation rules,
1.19 cvs 6645: </li>
1.18 cvs 6646: <li>
6647: with the content of the leaves of the structure (characters, symbols and
1.1 cvs 6648: graphical elements)
1.19 cvs 6649: </li>
1.18 cvs 6650: </ul>
6651: <p>
1.1 cvs 6652: Thus, for each node, the translator applies all rules associated with the
6653: element type, all rules associated with each attribute (local or global)
6654: carried by the element, and if the element is a leaf of the tree, it also
1.10 cvs 6655: applies translation rules for characters, symbols, or graphical elements,
1.18 cvs 6656: depending on the type of the leaf.</p>
6657: <p>
1.1 cvs 6658: Rules associated with the content of leaves are different from all other
6659: rules: they specify only how to translate character strings, symbols, and
6660: graphical elements. All other rules, whether associated with element types,
6661: with specific presentation rules or with attributes, are treated similarly.
1.18 cvs 6662: These rules primarily allow:</p>
6663: <ul>
6664: <li>
6665: generation of a text constant or variable before or after the contents of an
6666: element,
1.19 cvs 6667: </li>
1.18 cvs 6668: <li>
6669: modification of the order in which elements appear after translation,
1.19 cvs 6670: </li>
1.18 cvs 6671: <li>
6672: removal of an element in the translated document,
1.19 cvs 6673: </li>
1.18 cvs 6674: <li>
6675: and writing messages on the user's terminal during translation.
1.19 cvs 6676: </li>
1.18 cvs 6677: </ul>
6678: </div>
6679: </div>
1.1 cvs 6680:
1.18 cvs 6681: <div class="section">
1.1 cvs 6682:
1.18 cvs 6683: <h2><a name="sectb52">Translation definition language</a></h2>
6684: <p>
1.1 cvs 6685: Translation schemas are written in a custom language, called T, which is
6686: described in the rest of this chapter. The grammar of T is specified using
1.18 cvs 6687: the same <a href="#sectc321">meta-language</a> as was used for the S and P
1.1 cvs 6688: languages and the translation schemas are written using the same conventions
6689: as the structure and presentation schemas. In particular, the keywords of the
6690: T language (the stings between apostrophes in the following syntax rules) can
6691: be written in any combination of upper-case and lower-case letters, but
6692: identifiers created by the programmer must always be written in the same
1.18 cvs 6693: way.</p>
1.1 cvs 6694:
1.18 cvs 6695: <div class="subsection">
1.1 cvs 6696:
1.18 cvs 6697: <h3><a name="sectc521">Organization of a translation schema</a></h3>
6698: <p>
6699: A translation schema is begun by the <tt>TRANSLATION</tt> keyword and is
6700: terminated by the <tt>END</tt> keyword. The <tt>TRANSLATION</tt> keyword is
1.1 cvs 6701: followed by the name of the generic structure for which a translation is being
6702: defined and a semicolon. This name must be identical to the name which
1.18 cvs 6703: appears after the <tt>STRUCTURE</tt> keyword in the corresponding structure
6704: schema.</p>
6705: <p>
1.1 cvs 6706: After this declaration of the structure, the following material appears in
1.18 cvs 6707: order:</p>
6708: <ul>
6709: <li>
6710: the length of lines produced by the translation,
1.19 cvs 6711: </li>
1.18 cvs 6712: <li>
6713: the character delimiting the end of the line,
1.19 cvs 6714: </li>
1.18 cvs 6715: <li>
6716: the character string which the translator will insert if it must line-break
6717: the translated text,
1.19 cvs 6718: </li>
1.18 cvs 6719: <li>
6720: declarations of
6721: <ul>
6722: <li>
6723: buffers,
1.19 cvs 6724: </li>
1.18 cvs 6725: <li>
6726: counters,
1.19 cvs 6727: </li>
1.18 cvs 6728: <li>
6729: constants,
1.19 cvs 6730: </li>
1.18 cvs 6731: <li>
6732: variables,
1.19 cvs 6733: </li>
1.18 cvs 6734: </ul>
1.19 cvs 6735: </li>
1.18 cvs 6736: <li>
6737: translation rules associated with element types,
1.19 cvs 6738: </li>
1.18 cvs 6739: <li>
6740: translation rules associated with attributes,
1.19 cvs 6741: </li>
1.18 cvs 6742: <li>
6743: translation rules associated with specific presentation rules,
1.19 cvs 6744: </li>
1.18 cvs 6745: <li>
6746: translation rules associated with characters strings, symbols and graphical
6747: elements.
1.19 cvs 6748: </li>
1.18 cvs 6749: </ul>
6750: <p>
1.1 cvs 6751: Each of these sections is introduced by a keyword followed by a sequence of
6752: declarations. All of these sections are optional, expect for the translation
1.18 cvs 6753: rules associated with element types. Many <tt>TEXTTRANSLATE</tt> sections can
1.1 cvs 6754: appear, each defining the rules for translating character strings of a
1.18 cvs 6755: particular alphabet.</p>
6756: <pre> TransSchema ='TRANSLATION' ElemID ';'
1.1 cvs 6757: [ 'LINELENGTH' LineLength ';' ]
6758: [ 'LINEEND' CHARACTER ';' ]
6759: [ 'LINEENDINSERT' STRING ';' ]
6760: [ 'BUFFERS' BufferSeq ]
6761: [ 'COUNTERS' CounterSeq ]
6762: [ 'CONST' ConstSeq ]
6763: [ 'VAR' VariableSeq ]
6764: 'RULES' ElemSeq
6765: [ 'ATTRIBUTES' AttrSeq ]
6766: [ 'PRESENTATION' PresSeq ]
6767: < 'TEXTTRANSLATE' TextTransSeq >
6768: [ 'SYMBTRANSLATE' TransSeq ]
6769: [ 'GRAPHTRANSLATE' TransSeq ]
1.18 cvs 6770: 'END' .</pre>
6771: </div>
1.1 cvs 6772:
1.18 cvs 6773: <div class="subsection">
1.1 cvs 6774:
1.18 cvs 6775: <h3><a name="sectc522">Line length</a></h3>
6776: <p>
6777: If a <tt>LINELENGTH</tt> instruction is present after the structure
1.1 cvs 6778: declaration, the translator divides the text it produces into lines, each line
6779: having a length less than or equal to the integer which follows the
1.18 cvs 6780: <tt>LINELENGTH</tt> keyword. This maximum line length is expressed as a
1.1 cvs 6781: number of characters. The end of the line is marked by the character defined
1.18 cvs 6782: by the <tt>LINEEND</tt> instruction. When the translator breaks the lines on
1.1 cvs 6783: a space character in generated text, this space will be replaced by the
1.18 cvs 6784: character string defined by the <tt>LINEENDINSERT</tt> instruction.</p>
6785: <p>
6786: If the <tt>LINEEND</tt> instruction is not defined then the linefeed character
1.1 cvs 6787: (octal code 12) is used as the default line end character. If the
1.18 cvs 6788: <tt>LINEENDINSERT</tt> instruction is not defined, the linefeed character is
6789: inserted at the end of the produced lines. If there is no <tt>LINELENGTH</tt>
1.1 cvs 6790: instruction, the translated text is not divided into lines. Otherwise, if the
6791: translation rules generate line end marks, these marks remain in the
6792: translated text, but the length of the lines is not controlled by the
1.18 cvs 6793: translator.</p>
6794: <pre> LineLength = NUMBER .</pre>
6795: <blockquote class="example">
6796: <p>
6797: <strong>Example:</strong></p>
6798: <p>
6799: To limit the lines produced by the translator to a length of 80 characters,
6800: the following rule is written at the beginning of the translation schema.</p>
6801: <pre>LineLength 80;</pre>
6802: </blockquote>
6803: </div>
1.1 cvs 6804:
1.18 cvs 6805: <div class="subsection">
1.1 cvs 6806:
1.18 cvs 6807: <h3><a name="sectc523">Buffers</a></h3>
6808: <p>
1.1 cvs 6809: A buffer is a unit of memory managed by the translator, which can either
1.18 cvs 6810: contain text read from the terminal during the translation (see the <a
6811: href="#sectc5212"><tt>Read</tt> rule</a>), or the name of the last picture
1.1 cvs 6812: (bit-map) encountered by the translator in its traversal of the document.
1.2 cvs 6813: Remember the pictures are stored in files that are separate for the document
1.1 cvs 6814: files and that the canonical form contains only the names of the files in
1.18 cvs 6815: which the pictures are found.</p>
6816: <p>
1.1 cvs 6817: Thus, there are two types of buffers: buffers for reading from the terminal
1.18 cvs 6818: (filled by the <tt>Read</tt> rule) and the buffer of picture names (containing
1.2 cvs 6819: the name of the last picture encountered). A translation schema can use
6820: either type, one or several read buffers and one (and only one) picture name
1.18 cvs 6821: buffer.</p>
6822: <p>
6823: If any buffers are used, the <tt>BUFFERS</tt> keyword must be present,
1.1 cvs 6824: followed by declarations of every buffer used in the translation schema. Each
6825: buffer declaration is composed only of the name of the buffer, chosen freely
1.2 cvs 6826: by the programmer. The picture name buffer is identified by the
1.18 cvs 6827: <tt>Picture</tt> keyword, between parentheses, following the buffer name. The
6828: <tt>Picture</tt> keyword may only appear once. Each buffer declaration is
6829: terminated by a semicolon.</p>
6830: <pre> BufferSeq = Buffer < Buffer > .
1.1 cvs 6831: Buffer = BufferID [ '(' 'Picture' ')' ] ';' .
1.18 cvs 6832: BufferID = NAME .</pre>
6833: <blockquote class="example">
6834: <p>
6835: <strong>Example:</strong></p>
6836: <p>
1.3 cvs 6837: The following buffer declarations create a picture name buffer named
1.18 cvs 6838: <tt>pictureName</tt> and a read buffer named <a
6839: name="destname"><tt>DestName</tt></a>:</p>
6840: <pre>BUFFERS
6841: pictureName (Picture); DestName;</pre>
6842: </blockquote>
6843: </div>
1.1 cvs 6844:
1.18 cvs 6845: <div class="subsection">
1.1 cvs 6846:
1.18 cvs 6847: <h3><a name="sectc524">Counters</a></h3>
6848: <p>
1.1 cvs 6849: Certain translation rules generate text that varies according to the context
6850: of the element to which the rules apply. Variable text is defined either in
1.18 cvs 6851: the <a href="#sectc526"><tt>VAR</tt> section</a> of the translation schema or
6852: in the rule itself (see the <tt>Create</tt> and <tt>Write</tt> rules). Both
1.1 cvs 6853: types of definition rely on counters for the calculation of variable
1.18 cvs 6854: material.</p>
6855: <p>
1.1 cvs 6856: There are two types of counter: counters whose value is explicitely computed
1.18 cvs 6857: by applying <a href="#sectc5221"><tt>Set</tt> and <tt>Add</tt> rules</a>, and
1.1 cvs 6858: counters whose value is computed by a function associated with the counter.
6859: Those functions allow the same calculations as can be used in presentation
6860: schemas. As in a presentation schema, counters must be defined in the
1.18 cvs 6861: <tt>COUNTERS</tt> section of the translation schema before they are used.</p>
6862: <p>
6863: When counters are used in a translation schema, the <tt>COUNTERS</tt> keyword
1.1 cvs 6864: is followed by the declarations of every counter used. Each declaration is
6865: composed of the counter's name possibly followed by a colon and the counting
6866: function to be used for the counter. The declaration is terminated by a
1.18 cvs 6867: semi-colon. If the counter is explicitely computed by <tt>Set</tt> and
6868: <tt>Add</tt> rules, no counting function is indicated. If a counting function
6869: is indicated, <tt>Set</tt> and <tt>Add</tt> rules cannot be applied to that
6870: counter.</p>
6871: <p>
1.1 cvs 6872: The counting function indicates how the counter's value will be computed.
1.18 cvs 6873: Three functions are available: <tt>Rank</tt>, <tt>Rlevel</tt>, and
6874: <tt>Set</tt>.</p>
6875: <ul>
6876: <li>
6877: <tt>Rank of ElemID</tt> indicates that the counter's value is the rank of the
6878: element of type <tt>ElemID</tt> which encloses the element for which the
1.2 cvs 6879: counter is being evaluated. For the purposes of this function, an element of
1.18 cvs 6880: type <tt>ElemID</tt> is considered to enclose itself. This function is
6881: primarily used when the element of type <tt>ElemID</tt> is part of an
1.2 cvs 6882: aggregate or list, in which case the counter's value is the element's rank in
1.18 cvs 6883: its list or aggregate. Note that, unlike the <tt>Rank</tt> function for
6884: presentation schemas, the <tt>Page</tt> keyword cannot be used in place of the
6885: <tt>ElemID</tt>.
6886: <p>
6887: The type name <tt>ElemID</tt> can be followed by an integer. That number
1.1 cvs 6888: represents the relative level, among the ancestors of the concerned element,
1.18 cvs 6889: of the element whose rank is asked. If that relative level <i>n</i> is
6890: unsigned, the <i>n<sup>th</sup></i> element of type <tt>ElemID</tt>
6891: encountered when travelling the logical structure from the root to the
6892: concerned element is taken into account. If the relative level is negative,
6893: the logical structure is travelled in the other direction, from the concerned
6894: element to the root.</p>
1.19 cvs 6895: </li>
1.18 cvs 6896: <li>
6897: <tt>Rlevel of ElemID</tt> indicates that the counter's values is the relative
6898: level in the tree of the element for which the counter is being evaluated. The
6899: counter counts the number of elements of type <tt>ElemID</tt> which are found
6900: on the path between the root of the document's logical structure tree and the
6901: element (inclusive).
1.19 cvs 6902: </li>
1.18 cvs 6903: <li>
6904: <tt>Set n on Type1 Add m on Type2</tt> indicates that the counter's value is
6905: calculated as follows: in traversing the document from the beginning to the
6906: element for which the counter is being evaluated, the counter is set to the
6907: value <tt>n</tt> each time a <tt>Type1</tt> element is encountered and is
6908: incremented by the amount <tt>m</tt> each time a <tt>Type2</tt> element is
6909: encountered. The initial value <tt>n</tt> and the increment <tt>m</tt> are
1.1 cvs 6910: integers.
1.19 cvs 6911: </li>
1.18 cvs 6912: </ul>
6913: <p>
6914: As in a presentation schema, the <tt>Rank</tt> and <tt>Set</tt> functions can
1.1 cvs 6915: be modified by a numeric attribute which changes their initial value. This is
1.18 cvs 6916: indicated by the <tt>Init</tt> keyword followed by the numeric attribute's
6917: name. The <tt>Set</tt> function takes the value of the attribute instead of
6918: the <tt>InitValue</tt> (<tt>n</tt>). For the <tt>Rank</tt> function, the
1.1 cvs 6919: value of the attribute is considered to be the rank of the first element of
6920: the list (rather than the normal value of 1). Subsequent items in the list
6921: have their ranks shifted accordingly. In both cases, the attribute must be
1.18 cvs 6922: numeric and must be a local attribute of the root of the document itself.</p>
6923: <pre> CounterSeq = Counter < Counter > .
1.1 cvs 6924: Counter = CounterID [ ':' CounterFunc ] ';' .
6925: CounterID = NAME .
6926: CounterFunc = 'Rank' 'of' ElemID [ SLevelAsc ]
6927: [ 'Init' AttrID ] /
6928: 'Rlevel' 'of' ElemID /
6929: 'Set' InitValue 'On' ElemID
6930: 'Add' Increment 'On' ElemID
6931: [ 'Init' AttrID ] .
6932: SLevelAsc = [ '-' ] LevelAsc .
6933: LevelAsc = NUMBER .
6934: InitValue = NUMBER .
6935: Increment = NUMBER .
6936: ElemID = NAME .
1.18 cvs 6937: AttrID = NAME .</pre>
6938: <blockquote class="example">
6939: <p>
6940: <strong>Example:</strong></p>
6941: <p>
6942: If the body of a chapter is defined in the structure schema by:</p>
6943: <pre>Chapter_Body = LIST OF
1.1 cvs 6944: (Section = BEGIN
6945: Section_Title = Text;
6946: Section_Body = BEGIN
6947: Paragraphs;
6948: Section;
6949: END;
6950: END
1.18 cvs 6951: );</pre>
6952: <p>
6953: (sections are defined recursively), a counter can be defined giving the <a
6954: name="sectnum">number of a section</a> within its level in the hierarchy:</p>
6955: <pre>COUNTERS
6956: SectionNumber : Rank of Section;</pre>
6957: <p>
6958: A counter holding the hierarchic level of a section:</p>
6959: <pre> SectionLevel : Rlevel of Section;</pre>
6960: <p>
6961: A <a name="uniquenum">counter</a> which sequentially numbers all the
6962: document's sections, whatever their hierarchic level:</p>
6963: <pre> UniqueSectNum : Set 0 on Document Add 1 on Section;</pre>
6964: </blockquote>
6965: </div>
1.1 cvs 6966:
1.18 cvs 6967: <div class="subsection">
1.1 cvs 6968:
1.18 cvs 6969: <h3><a name="sectc525">Constants</a></h3>
6970: <p>
1.1 cvs 6971: A common feature of translation rules is the generation of constant text. This
1.18 cvs 6972: text can be defined in the rule that generates it (see for example the <a
6973: href="#sectc5210"><tt>Create</tt></a> and <a
6974: href="#sectc5211"><tt>Write</tt></a> rules); but it can also be defined once
6975: in the constant declaration section and used many times in different rules.
6976: The latter option is preferable when the same text is used in several rules or
6977: several <a href="#sectc526">variables</a>.</p>
6978: <p>
6979: The <tt>CONST</tt> keyword begins the constant declaration section of the
1.1 cvs 6980: translation schema. It must be omitted if no constants are declared. Each
6981: constant declaration is composed of the constant name, an equals sign, and the
6982: constant's value, which is a character string between apostrophes. A constant
1.18 cvs 6983: declaration is terminated by a semicolon.</p>
6984: <pre> ConstSeq = Const < Const > .
1.1 cvs 6985: Const = ConstID '=' ConstValue ';' .
6986: ConstID = NAME .
1.18 cvs 6987: ConstValue = STRING .</pre>
6988: <blockquote class="example">
6989: <p>
6990: <strong><a name="levelexample">Example:</a></strong></p>
6991: <p>
6992: The following rule assigns the name <tt>TxtLevel</tt> to the character string
6993: ``Level'':</p>
6994: <pre>CONST
6995: TxtLevel = 'Level';</pre>
6996: </blockquote>
6997: </div>
1.1 cvs 6998:
1.18 cvs 6999: <div class="subsection">
1.1 cvs 7000:
1.18 cvs 7001: <h3><a name="sectc526">Variables</a></h3>
7002: <p>
1.10 cvs 7003: Variables allow to define variable text which is generated by the
1.18 cvs 7004: <tt>Create</tt> and <tt>Write</tt> rules. They are also used to define file
7005: names which are used in the <tt>Create</tt>, <tt>ChangeMainFile</tt>,
7006: <tt>RemoveFile</tt>, and <tt>Indent</tt> rules. Variables can be defined
7007: either in the <tt>VAR</tt> section of the translation schema or directly in
7008: the rules which use them. Variables that define file names must be declared
7009: in the <tt>VAR</tt> section, and when the same variable is used several times
7010: in the translation schema, it makes sense to define it globally in the
7011: <tt>VAR</tt> section. This section is only present if at least one variable
7012: is defined globally.</p>
7013: <p>
7014: After the <tt>VAR</tt> keyword, each global variable is defined by its name, a
1.1 cvs 7015: colon separator and a sequence of functions (at least one function). Each
7016: variable definition is terminated by a semicolon. Functions determine the
7017: different parts which together give the value of the variable. The value is
7018: obtained by concatenating the strings produced by each of the functions. Seven
7019: types of functions are available. Each variable definition may use any number
1.18 cvs 7020: of functions of each type.</p>
7021: <ul>
7022: <li>
7023: The function <tt>Value(Counter)</tt>returns a string representing the value
7024: taken by the counter when it is evaluated for the element in whose rule the
7025: variable is used. The counter must have been declared in the
7026: <tt>COUNTERS</tt> section of the translation schema. When the counter is
1.2 cvs 7027: expressed in arabic numerals, the counter name can be followed by a colon and
7028: an integer indicating a minimum length (number of characters) for the string;
7029: if the counter's value is normally expressed with fewer characters than the
7030: required minimum, zeroes are added to the front of the string to achieve the
1.5 cvs 7031: minimum length.
1.18 cvs 7032: <p>
1.1 cvs 7033: By default, the counter value is written in arabic digits. If another
7034: representation of that value is needed, the counter name must be followed by a
1.18 cvs 7035: comma and one of the following keywords:</p>
7036: <ul>
7037: <li>
7038: <tt>Arabic</tt>: arabic numerals (default value),
1.19 cvs 7039: </li>
1.18 cvs 7040: <li>
7041: <tt>LRoman</tt>: lower-case roman numerals,
1.19 cvs 7042: </li>
1.18 cvs 7043: <li>
7044: <tt>URoman</tt>: upper-case roman numerals,
1.19 cvs 7045: </li>
1.18 cvs 7046: <li>
7047: <tt>Uppercase</tt>: upper-case letter,
1.19 cvs 7048: </li>
1.18 cvs 7049: <li>
7050: <tt>Lowercase</tt>: lower-case letter.
1.19 cvs 7051: </li>
1.18 cvs 7052: </ul>
1.19 cvs 7053: </li>
1.18 cvs 7054: <li>
7055: The function <tt>FileDir</tt>, without parameter, returns a string
1.2 cvs 7056: representing the name of the directory of the output file that has been given
7057: as a parameter to the translation program. The string includes a character '/'
7058: at the end.
1.19 cvs 7059: </li>
1.18 cvs 7060: <li>
7061: The function <tt>FileName</tt>, without parameter, returns a string
1.2 cvs 7062: representing the name of the output file that has been given as a parameter to
7063: the translation program. The file extension (the character string that
7064: terminate the file name, after a dot) is not part of that string.
1.19 cvs 7065: </li>
1.18 cvs 7066: <li>
7067: The function <tt>Extension</tt>, without parameter, returns a string
1.2 cvs 7068: representing the extension of the file name. That string is empty if the file
7069: name that has been given as a parameter to the translation program has no
7070: extension. If there is an extension, its first character is a dot.
1.19 cvs 7071: </li>
1.18 cvs 7072: <li>
7073: The function <tt>DocumentName</tt>, without parameter, returns a string
1.2 cvs 7074: representing the name of the document being translated.
1.19 cvs 7075: </li>
1.18 cvs 7076: <li>
7077: The function <tt>DocumentDir</tt>, without parameter, returns a string
1.2 cvs 7078: representing the directory containing the document being translated.
1.19 cvs 7079: </li>
1.18 cvs 7080: <li>
7081: The function formed by the name of a constant returns that constant's value.
1.19 cvs 7082: </li>
1.18 cvs 7083: <li>
7084: The function formed by a character string between apostrophes returns that
1.1 cvs 7085: string.
1.19 cvs 7086: </li>
1.18 cvs 7087: <li>
7088: The function formed by the name of a buffer returns the contents of that
1.2 cvs 7089: buffer. If the named buffer is the picture buffer, then the name of the last
7090: picture encountered is returned. Otherwise, the buffer is a read buffer and
7091: the value returned is text previously read from the terminal. If the buffer
1.18 cvs 7092: is empty (no picture has been encountered or the <tt>Read</tt> rule has not
1.2 cvs 7093: been executed for the buffer), then the empty string is returned.
1.19 cvs 7094: </li>
1.18 cvs 7095: <li>
7096: The function formed by an attribute name takes the value of the indicated
1.2 cvs 7097: attribute for the element to which the variable applies. If the element does
7098: not have that attribute, then the element's ancestor are searched toward the
7099: root of the tree. If one of the ancestors does have the attribute then its
7100: value is used. If no ancestors have the attribute, then the value of the
1.1 cvs 7101: function is the empty string.
1.19 cvs 7102: </li>
1.18 cvs 7103: </ul>
7104: <pre> VariableSeq = Variable < Variable > .
1.1 cvs 7105: Variable = VarID ':' Function < Function > ';' .
7106: VarID = NAME .
7107: Function ='Value' '(' CounterID [ ':' Length ]
7108: [ ',' CounterStyle ] ')' /
7109: 'FileDir' / 'FileName' / 'Extension' /
7110: 'DocumentName' / 'DocumentDir' /
7111: ConstID / CharString /
7112: BufferID / AttrID .
7113: Length = NUMBER .
7114: CounterStyle= 'Arabic' / 'LRoman' / 'URoman' /
7115: 'Uppercase' / 'Lowercase' .
1.18 cvs 7116: CharString = STRING .</pre>
7117: <blockquote class="example">
7118: <p>
7119: <strong>Example:</strong></p>
7120: <p>
1.3 cvs 7121: To create, at the beginning of each section of the translated document, text
7122: composed of the string ``Section'' followed by the section number, the
1.18 cvs 7123: following <a name="varsectexample">variable definition</a> might be used:</p>
7124: <pre>VAR
7125: SectionVar : 'Section' Value(SectionNumber);</pre>
7126: <p>
7127: (see the definition of <a href="#sectnum"><tt>SectionNumber</tt></a>).</p>
7128: <p>
1.1 cvs 7129: The following variable definition can be used to create, at the beginning of
7130: each section, the text ``Level'' followed by the hierarchical level of the
1.18 cvs 7131: section. It used the constant defined above.</p>
7132: <pre> LevelVar : TxtLevel Value(SectionLevel);</pre>
7133: <p>
7134: (see the definitions of <a href="#sectnum"><tt>SectionLevel</tt></a> and of <a
7135: href="#levelexample"><tt>TxtLevel</tt></a>).</p>
7136: <p>
7137: To generate the translation of each section in a different file (see <a
7138: href="#sectc5220">rule <tt>ChangeMainFile</tt></a>), the name of these files
7139: might be defined by the following variable:</p>
7140: <pre> VarOutpuFile : FileName Value(SectionNumber)
7141: Extension;</pre>
7142: <p>
7143: If <tt>output.txt</tt> is the name of the <a name="varoutputfile">output
7144: file</a> specified when starting the translation program, translated sections
7145: are written in files <tt>output1.txt</tt>, <tt>output2.txt</tt>, etc.</p>
7146: </blockquote>
7147: </div>
7148:
7149: <div class="subsection">
7150:
7151: <h3><a name="sectc527">Translating structure elements</a></h3>
7152: <p>
7153: The <tt>RULES</tt> keyword introduces the translation rules which will be
1.1 cvs 7154: applied to the various structured element types. Translation rules can be
7155: specified for each element type defined in the structure schema, including the
1.18 cvs 7156: base types defined implicitly, whose names are <tt>TEXT_UNIT</tt>,
7157: <tt>PICTURE_UNIT</tt>, <tt>SYMBOL_UNIT</tt>, <tt>GRAPHIC_UNIT</tt> and
7158: <tt>PAGE_UNIT</tt>. But it is not necessary to specify rules for every
7159: defined type.</p>
7160: <p>
1.1 cvs 7161: If there are no translation rules for an element type, the elements that it
7162: contains (and which may have rules themselves) will still be translated, but
7163: the translator will produce nothing for the element itself. To make the
1.18 cvs 7164: translator completely ignore the content of an element the <a
7165: href="#sectc5217"><tt>Remove</tt> rule</a> must be used.</p>
7166: <p>
1.1 cvs 7167: The translation rules for an element type defined in the structure schema are
7168: written using the name of the type followed by a colon and the list of
1.18 cvs 7169: applicable rules. When the element type is a <a href="#sectd3285">mark
7170: pair</a>, but only in this case, the type name must be preceded by the
7171: <tt>First</tt> or <tt>Second</tt> keyword. This keyword indicates whether the
7172: rules that follow apply to the first or second mark of the pair.</p>
7173: <p>
1.1 cvs 7174: The list of rules can take several forms. It may be a simple non-conditional
7175: rule. It can also be formed by a condition followed by one or more simple
1.18 cvs 7176: rules. Or it can be a block of rules beginning with the <tt>BEGIN</tt>
7177: keyword and ending with the <tt>END</tt> keyword and a semicolon. This block
1.1 cvs 7178: of rules can contain one or more simple rules and/or one or more conditions,
1.18 cvs 7179: each followed by one or more simple rules.</p>
7180: <pre> ElemSeq = TransType < TransType > .
1.1 cvs 7181: TransType = [ FirstSec ] ElemID ':' RuleSeq .
7182: FirstSec = 'First' / 'Second' .
7183: RuleSeq = Rule / 'BEGIN' < Rule > 'END' ';' .
7184: Rule = SimpleRule / ConditionBlock .
7185: ConditionBlock = 'IF' ConditionSeq SimpleRuleSeq .
7186: SimpleRuleSeq = 'BEGIN' < SimpleRule > 'END' ';' /
1.18 cvs 7187: SimpleRule .</pre>
7188: </div>
1.1 cvs 7189:
1.18 cvs 7190: <div class="subsection">
1.1 cvs 7191:
1.18 cvs 7192: <h3><a name="sectc528">Conditional rules</a></h3>
7193: <p>
1.1 cvs 7194: In a translation schema, the translation rules are either associated with
7195: element types or with attribute values or with a specific presentation. They
7196: are applied by the translator each time an element of the corresponding type
7197: is encountered in the translated document or each time the attribute value is
7198: carried by an element or also, each time the specific translation is attached
7199: to an element. This systematic application of the rules can be relaxed: it is
7200: possible to add a condition to one or more rules, so that these rules are only
1.18 cvs 7201: applied when the condition is true.</p>
7202: <p>
7203: A condition begins with the keyword <tt>IF</tt>, followed by a sequence of
1.1 cvs 7204: elementary conditions. Elementary conditions are separated from each other by
1.18 cvs 7205: the <tt>AND</tt> keyword. If there is only one elementary condition, this
1.1 cvs 7206: keyword is absent. The rules are only applied if all the elementary
7207: conditions are true. The elementary condition can be negative; it is then
1.18 cvs 7208: preceded by the <tt>NOT</tt> keyword.</p>
7209: <p>
1.1 cvs 7210: When the translation rule(s) controlled by the condition apply to a reference
7211: element or a reference attribute, an elementary condition can also apply to
1.18 cvs 7212: element referred by this reference. The <tt>Target</tt> keyword is used for
1.1 cvs 7213: that purpose. It must appear before the keyword defining the condition
1.18 cvs 7214: type.</p>
7215: <p>
1.1 cvs 7216: Depending on their type, some conditions may apply either to the element with
1.5 cvs 7217: which they are associated, or to one of its ancestor. In the case of an
1.18 cvs 7218: ancestor, the key word <tt>Ancestor</tt> must be used, followed by</p>
7219: <ul>
7220: <li>
7221: either an integer which represents the number of levels in the tree between
7222: the element and the ancestor of interest,
1.19 cvs 7223: </li>
1.18 cvs 7224: <li>
7225: or the type name of the ancestor of interest. If that type is defined in a
7226: separate structure schema, the name of that schema must follow between
1.1 cvs 7227: parentheses.
1.19 cvs 7228: </li>
1.18 cvs 7229: </ul>
7230: <p>
1.2 cvs 7231: There is a special case for the parent element, which can be simply written
1.18 cvs 7232: <tt>Parent</tt> instead of <tt>Ancestor 1</tt>.</p>
7233: <p>
7234: Only conditions <tt>First</tt>, <tt>Last</tt>, <tt>Referred</tt>,
7235: <tt>Within</tt>, <tt>Attributes</tt>, <tt>Presentation</tt>, <tt>Comment</tt>
1.1 cvs 7236: and those concerning an attribute or a specific presentation can apply to an
1.18 cvs 7237: ancestor. Conditions <tt>Defined</tt>, <tt>FirstRef</tt>, <tt>LastRef</tt>,
7238: <tt>ExternalRef</tt>, <tt>Alphabet</tt>, <tt>FirstAttr</tt>,
7239: <tt>LastAttr</tt>, <tt>ComputedPage</tt>, <tt>StartPage</tt>,
7240: <tt>UserPage</tt>, <tt>ReminderPage</tt>, <tt>Empty</tt> cannot be preceded by
7241: keywords <tt>Parent</tt> or <tt>Ancestor</tt>.</p>
7242: <p>
7243: In condition <tt>Referred</tt> and in the condition that applies to a named
7244: attribute, a symbol '<tt>*</tt>' can indicate that the condition is related
1.5 cvs 7245: only to the element itself. If this symbol is not present, not only the
1.18 cvs 7246: element is considered, but also its ancestor, at any level.</p>
7247: <p>
1.1 cvs 7248: The form of an elementary condition varies according to the type of
1.18 cvs 7249: condition.</p>
1.1 cvs 7250:
1.18 cvs 7251: <div class="subsubsection">
1.1 cvs 7252:
1.18 cvs 7253: <h4><a name="sectd5281">Conditions based on the logical position of the
7254: element</a></h4>
7255: <p>
1.1 cvs 7256: The condition can be on the position of the element in the document's logical
7257: structure tree. It is possible to test whether the element is the first
1.18 cvs 7258: (<tt>First</tt>) or last (<tt>Last</tt>) among its siblings or if it is not
7259: the first (<tt>NOT First</tt>) or not the last (<tt>NOT Last</tt>).</p>
7260: <p>
1.1 cvs 7261: It is also possible to test if the element is contained in an element of a
1.18 cvs 7262: given type (<tt>Within</tt>) or if it is not (<tt>NOT Within</tt>). If that
1.1 cvs 7263: element type is defined in a structure schema which is not the one which
7264: corresponds to the translation schema, the type name of this element must be
7265: followed, between parentheses, by the name of the structure schema which
1.18 cvs 7266: defines it.</p>
7267: <p>
7268: If the keyword <tt>Within</tt> is preceded by <tt>Immediately</tt>, the
7269: condition is satisfied only if the <em>parent</em> element has the type
7270: indicated. If the word <tt>Immediately</tt> is missing, the condition is
7271: satisfied if any <em>ancestor</em> has the type indicated.</p>
7272: <p>
7273: An integer <i>n</i> can appear between the keyword <tt>Within</tt> and the
1.1 cvs 7274: type. It specifies the number of ancestors of the indicated type that must be
7275: present for the condition to be satisfied. If the keyword
1.18 cvs 7276: <tt>Immediately</tt> is also present, the <i>n</i> immediate ancestors of the
7277: element must have the indicated type. The integer <i>n</i> must be positive
7278: or zero. It can be preceded by <tt><</tt> or <tt>></tt> to indicate a
1.1 cvs 7279: maximum or minimum number of ancestors. If these symbols are missing, the
1.18 cvs 7280: condition is satisfied only if it exists exactly <i>n</i> ancestors. When
7281: this number is missing, it is equivalent to > 0.</p>
7282: <p>
1.11 cvs 7283: If the condition applies to translation rules associated with an attribute,
1.18 cvs 7284: i.e. if it is in the <tt>ATTRIBUTES</tt> section of the presentation schema,
1.11 cvs 7285: the condition can be simply an element name. Translation rules are then
1.18 cvs 7286: executed only if the attribute is attached to an element of that type. The
7287: keyword <tt>NOT</tt> before the element name indicates that the translation
7288: rules must be executed only if the element is not of the type indicated.</p>
7289: </div>
1.1 cvs 7290:
1.18 cvs 7291: <div class="subsubsection">
1.1 cvs 7292:
1.18 cvs 7293: <h4><a name="sectd5282">Conditions on references</a></h4>
7294: <p>
1.1 cvs 7295: References may be taken into account in conditions, which can be based on the
1.18 cvs 7296: fact that the element, or one of its ancestors (unless symbol <tt>*</tt> is
7297: present), is designated by a at least one reference (<tt>Referred</tt>) or by
7298: none (<tt>NOT Referred</tt>). If the element or attribute to which the
1.1 cvs 7299: condition is attached is a reference, the condition can be based on the fact
7300: that it acts as the first reference to the designated element
1.18 cvs 7301: (<tt>FirstRef</tt>), or as the last (<tt>LastRef</tt>), or as a reference to
7302: an element located in another document (<tt>ExternalRef</tt>). Like all
7303: conditions, conditions on references can be inverted by the <tt>NOT</tt>
7304: keyword.</p>
7305: </div>
7306:
7307: <div class="subsubsection">
7308:
7309: <h4><a name="sectd5283">Conditions on the parameters</a></h4>
7310: <p>
7311: Elements which are <a href="#sectc326">parameters</a> can be given a
7312: particular condition which is based on whether or not the parameter is given a
7313: value in the document (<tt>Defined</tt> or <tt>NOT Defined</tt>,
7314: respectively).</p>
7315: </div>
1.1 cvs 7316:
1.18 cvs 7317: <div class="subsubsection">
1.1 cvs 7318:
1.18 cvs 7319: <h4><a name="sectd5284">Conditions on the alphabets</a></h4>
7320: <p>
1.1 cvs 7321: The character string base type (and only this type) can use the condition
1.18 cvs 7322: <tt>Alphabet = a</tt> which indicates that the translation rule(s) should only
1.1 cvs 7323: apply if the alphabet of the character string is the one whose name appears
1.18 cvs 7324: after the equals sign (or is not, if there is a preceding <tt>NOT</tt>
1.1 cvs 7325: keyword). This condition cannot be applied to translation rules of an
1.18 cvs 7326: attribute.</p>
7327: <p>
1.1 cvs 7328: In the current implementation of Thot, the available alphabets are the
1.18 cvs 7329: <tt>Latin</tt> alphabet and the <tt>Greek</tt> alphabet.</p>
7330: </div>
1.1 cvs 7331:
1.18 cvs 7332: <div class="subsubsection">
1.1 cvs 7333:
1.18 cvs 7334: <h4><a name="sectd5285">Conditions on page breaks</a></h4>
7335: <p>
1.1 cvs 7336: The page break base type (and only this type) can use the following
1.18 cvs 7337: conditions: <tt>ComputedPage</tt>, <tt>StartPage</tt>, <tt>UserPage</tt>, and
7338: <tt>ReminderPage</tt>. The <tt>ComputedPage</tt> condition indicates that the
1.1 cvs 7339: translation rule(s) should apply if the page break was created automatically
1.18 cvs 7340: by Thot; the <tt>StartPage</tt> condition is true if the page break is
7341: generated before the element by the <tt>Page</tt> rule of the P language; the
7342: <tt>UserPage</tt> condition applies if the page break was inserted by the
7343: user; and the <tt>ReminderPage</tt> is applied if the page break is a reminder
7344: of page breaking.</p>
7345: </div>
1.1 cvs 7346:
1.18 cvs 7347: <div class="subsubsection">
1.1 cvs 7348:
1.18 cvs 7349: <h4><a name="sectd5286">Conditions on the element's content</a></h4>
7350: <p>
1.1 cvs 7351: The condition can be based on whether or not the element is empty. An element
7352: which has no children or whose leaves are all empty is considered to be empty
1.18 cvs 7353: itself. This condition is expressed by the <tt>Empty</tt> keyword, optionally
7354: preceded by the <tt>NOT</tt> keyword.</p>
7355: </div>
1.1 cvs 7356:
1.18 cvs 7357: <div class="subsubsection">
1.1 cvs 7358:
1.18 cvs 7359: <h4><a name="sectd5287">Conditions on the presence of comments</a></h4>
7360: <p>
1.1 cvs 7361: The condition can be based on the presence or absence of comments associated
7362: with the translated element. This condition is expressed by the keyword
1.18 cvs 7363: <tt>Comment</tt>, optionally preceded by the keyword <tt>NOT</tt>.</p>
7364: </div>
1.1 cvs 7365:
1.18 cvs 7366: <div class="subsubsection">
1.1 cvs 7367:
1.18 cvs 7368: <h4><a name="sectd5288">Conditions on the presence of specific presentation
7369: rules</a></h4>
7370: <p>
1.1 cvs 7371: The condition can be based on the presence or absence of specific presentation
7372: rules associated with the translated element, whatever the rules, their value
7373: or their number. This condition is expressed by the keyword
1.18 cvs 7374: <tt>Presentation</tt>, optionally preceded by the <tt>NOT</tt> keyword.</p>
7375: </div>
1.1 cvs 7376:
1.18 cvs 7377: <div class="subsubsection">
1.1 cvs 7378:
1.18 cvs 7379: <h4><a name="sectd5289">Conditions on the presence of logical
7380: attributes</a></h4>
7381: <p>
1.1 cvs 7382: In the same way, the condition can be based on the presence or absence of
7383: attributes associated with the translated elements, no matter what the
1.18 cvs 7384: attributes or their values. The <tt>Attributes</tt> keyword expresses this
7385: condition.</p>
7386: </div>
1.1 cvs 7387:
1.18 cvs 7388: <div class="subsubsection">
1.1 cvs 7389:
1.18 cvs 7390: <h4><a name="sectd52810">Conditions on logical attributes</a></h4>
7391: <p>
1.1 cvs 7392: If the condition appears in the translation rules of an attribute, the
1.18 cvs 7393: <tt>FirstAttr</tt> and <tt>LastAttr</tt> keywords can be used to indicate that
1.1 cvs 7394: the rules must only be applied if this attribute is the first attribute for
7395: the translated element or if it is the last (respectively). These conditions
1.18 cvs 7396: can also be inverted by the <tt>NOT</tt> keyword.</p>
7397: <p>
1.1 cvs 7398: Another type of condition can only be applied to the translation rules when
1.18 cvs 7399: the element being processed (or one of its ancestors if symbol <tt>*</tt> is
1.1 cvs 7400: missing) has a certain attribute, perhaps with a certain value or, in
7401: contrast, when the element does not have this attribute with this value. The
7402: condition is specified by writing the name of the attribute after the keyword
1.18 cvs 7403: <tt>IF</tt> or <tt>AND</tt>. The <tt>NOT</tt> keyword can be used to invert
1.1 cvs 7404: the condition. If the translation rules must be applied to any element which
7405: has this attribute (or does not have it, if the condition is inverted) no
7406: matter what the attribute's value, the condition is complete. If, in
7407: contrast, the condition applies to one or more values of the attribute, these
7408: are indicated after the name of the attribute, except for reference attributes
1.18 cvs 7409: which do not have values.</p>
7410: <p>
7411: The representation of the values of an <a name="relattr">attribute</a> in a
1.1 cvs 7412: condition depends on the attribute's type. For attributes with enumerated or
7413: textual types, the value (a name or character string between apostrophes,
7414: respectively) is simply preceded by an equals sign. For numeric attributes,
7415: the condition can be based on a single value or on a range of values. In the
7416: case of a unique value, this value (an integer) is simply preceded by an
1.18 cvs 7417: equals sign. Conditions based on ranges of values have several forms:</p>
7418: <ul>
7419: <li>
7420: all values less than a given value (the value is preceded by a ``less than''
7421: sign).
1.19 cvs 7422: </li>
1.18 cvs 7423: <li>
7424: all values greater than a given value (the value is preceded by a ``greater
1.1 cvs 7425: than'' sign).
1.19 cvs 7426: </li>
1.18 cvs 7427: <li>
7428: all values falling in an interval, bounds included. The range of values is
7429: then specified <tt>IN [</tt>Minimum <tt>..</tt>Maximum<tt>]</tt>, where
1.2 cvs 7430: Minimum and Maximum are integers.
1.19 cvs 7431: </li>
1.18 cvs 7432: </ul>
7433: <p>
1.2 cvs 7434: All numeric values may be negative. The integer is simply preceded by a minus
1.18 cvs 7435: sign.</p>
7436: <p>
7437: Both local and global attributes can be used in conditions.</p>
7438: </div>
1.1 cvs 7439:
1.18 cvs 7440: <div class="subsubsection">
1.1 cvs 7441:
1.18 cvs 7442: <h4><a name="sectd52811">Conditions on specific presentation rules</a></h4>
7443: <p>
1.1 cvs 7444: It is possible to apply translation rules only when the element being
7445: processed has or does not have a specific presentation rule, possibly with a
7446: certain value. The condition is specified by writing the name of the
1.18 cvs 7447: presentation rule after the keyword <tt>IF</tt> or <tt>AND</tt>. The
7448: <tt>NOT</tt> keyword can be used to invert the condition. If the translation
1.1 cvs 7449: rules must be applied to any element which has this presentation rule (or does
7450: not have it, if the condition is inverted) no matter what the rule's value,
7451: the condition is complete. If, in contrast, the condition applies to one or
7452: more values of the rule, these are indicated after the name of the
1.18 cvs 7453: attribute.</p>
7454: <p>
1.1 cvs 7455: The representation of presentation rule values in a condition is similar to
7456: that for attribute values. The representation of these values depend on the
7457: type of the presentation rule. There are three categories of presentation
1.18 cvs 7458: rules:</p>
7459: <ul>
7460: <li>
7461: those taking numeric values (<tt>Size, Indent, LineSpacing, LineWeight</tt>),
1.19 cvs 7462: </li>
1.18 cvs 7463: <li>
7464: those with values taken from a predefined list (<tt>Adjust, Justify,
1.24 cvs 7465: Hyphenate, Style, Weight, Font, UnderLine, Thickness, LineStyle</tt>),
1.19 cvs 7466: </li>
1.18 cvs 7467: <li>
7468: those whose value is a name (<tt>FillPattern, Background, Foreground</tt>).
1.19 cvs 7469: </li>
1.18 cvs 7470: </ul>
7471: <p>
1.1 cvs 7472: For presentation rules which take numeric values, the condition can take a
7473: unique value or a range of values. In the case of a unique value, this value
7474: (an integer) is simply preceded by an equals sign. Conditions based on ranges
1.18 cvs 7475: of values have several forms:</p>
7476: <ul>
7477: <li>
7478: all values less than a given value (the value is preceded by a ``less than''
7479: sign).
1.19 cvs 7480: </li>
1.18 cvs 7481: <li>
7482: all values greater than a given value (the value is preceded by a ``greater
1.1 cvs 7483: than'' sign).
1.19 cvs 7484: </li>
1.18 cvs 7485: <li>
7486: all values falling in an interval, bounds included. The range of values is
7487: then specified <tt>IN [</tt>Minimum <tt>..</tt>Maximum<tt>]</tt>, where
1.2 cvs 7488: Minimum and Maximum are integers.
1.19 cvs 7489: </li>
1.18 cvs 7490: </ul>
7491: <p>
7492: Values for the <tt>Indent</tt>rule may be negative. The integer is then
1.2 cvs 7493: simply preceded by a minus sign and represents how far the first line starts
1.18 cvs 7494: to the left of the other lines.</p>
7495: <p>
1.1 cvs 7496: For presentation rules whose values are taken from predefined lists, the value
7497: which satisfies the condition is indicated by an equals sign followed by the
1.18 cvs 7498: name of the value.</p>
7499: <p>
1.1 cvs 7500: For presentation rule whose values are names, the value which satisfies the
7501: condition is indicated by the equals sign followed by the value's name. The
1.18 cvs 7502: names of fill patterns (the <tt>FillPattern</tt> rule) and of colors (the
7503: <tt>Foreground</tt> and <tt>Background</tt> rules) known to Thot are the same
7504: as in the P language.</p>
7505: <p>
1.1 cvs 7506: The syntax of conditions based on the specific presentation is the same as the
1.18 cvs 7507: syntax used to express the <a href="#sectc5224">translation of specific
7508: presentation rules</a>.</p>
7509: <p>
1.1 cvs 7510: When a condition has only one rule, the condition is simply followed by that
7511: rule. If it has several rules, they are placed after the condition between
1.18 cvs 7512: the keywords <tt>BEGIN</tt> and <tt>END</tt>.</p>
7513: <pre> ConditionSeq = Condition [ 'AND' Condition ] .
1.1 cvs 7514: Condition = [ 'NOT' ] [ 'Target' ] Cond .
7515: Cond = CondElem / CondAscend .
7516: CondElem ='FirstRef' / 'LastRef' /
7517: 'ExternalRef' /
7518: 'Defined' /
7519: 'Alphabet' '=' Alphabet /
7520: 'ComputedPage' / 'StartPage' /
7521: 'UserPage' / 'ReminderPage' /
7522: 'Empty' /
1.11 cvs 7523: ElemID /
1.1 cvs 7524: 'FirstAttr' / 'LastAttr' .
7525: CondAscend = [ Ascend ] CondOnAscend .
7526: Ascend = '*' / 'Parent' / 'Ancestor' LevelOrType .
7527: LevelOrType = CondRelLevel / ElemID [ ExtStruct ] .
7528: CondRelLevel = NUMBER .
7529: CondOnAscend ='First' / 'Last' /
7530: 'Referred' /
7531: [ 'Immediately' ] 'Within' [ NumParent ]
7532: ElemID [ ExtStruct ] /
7533: 'Attributes' /
7534: AttrID [ RelatAttr ] /
7535: 'Presentation' /
7536: PresRule /
7537: 'Comment' .
7538: NumParent = [ GreaterLess ] NParent .
7539: GreaterLess = '>' / '<' .
7540: NParent = NUMBER.
7541: ExtStruct = '(' ElemID ')' .
7542: Alphabet = NAME .
7543: RelatAttr ='=' Value /
7544: '>' [ '-' ] Minimum /
7545: '<' [ '-' ] Maximum /
7546: 'IN' '[' [ '-' ] MinInterval '..'
7547: [ '-' ] MaxInterval ']' .
7548: Value = [ '-' ] IntegerVal / TextVal / AttrValue .
7549: Minimum = NUMBER .
7550: Maximum = NUMBER .
7551: MinInterval = NUMBER .
7552: MaxInterval = NUMBER .
7553: IntegerVal = NUMBER .
7554: TextVal = STRING .
1.18 cvs 7555: AttrValue = NAME .</pre>
7556: <blockquote class="example">
7557: <p>
7558: <strong>Example:</strong></p>
7559: <p>
1.3 cvs 7560: Suppose that after each element of type Section_Title it is useful to produce
1.18 cvs 7561: the text <tt>\label{SectX}</tt> where <tt>X</tt> represents the section
7562: number, but only if the section is designated by one or more references in the
7563: document. The following conditional rule produces this effect:</p>
7564: <pre>RULES
1.1 cvs 7565: Section_Title :
7566: IF Referred
1.18 cvs 7567: Create ('\label{Sect' Value(UniqueSectNum) '}\12') After;</pre>
7568: <p>
7569: (the declaration of the <a href="#sectc5224"><tt>UniqueSectNum</tt>
7570: counter</a> is given above). The string <tt>\12</tt> represents a line
7571: break.</p>
7572: </blockquote>
7573: <blockquote class="example">
7574: <p>
7575: <strong>Example:</strong></p>
7576: <p>
1.3 cvs 7577: Suppose that for elements of the Elmnt type it would be useful to produce a
7578: character indicating the value of the numeric attribute Level associated with
7579: the element: an ``A'' for all values of Level less than 3, a ``B'' for values
7580: between 3 and 10 and a ``C'' for values greater than 10. This can be achieved
1.18 cvs 7581: by writing the following rules for the Elmnt type:</p>
7582: <pre>RULES
1.1 cvs 7583: Elmnt :
7584: BEGIN
7585: IF Level < 3
7586: Create 'A';
7587: IF Level IN [3..10]
7588: Create 'B';
7589: IF Level > 10
7590: Create 'C';
1.18 cvs 7591: END;</pre>
7592: </blockquote>
7593: </div>
7594: </div>
1.1 cvs 7595:
1.18 cvs 7596: <div class="subsection">
1.1 cvs 7597:
1.18 cvs 7598: <h3><a name="sectc529">Translation rules</a></h3>
7599: <p>
1.14 cvs 7600: Fifteen types of translation rules can be associated with element types and
1.18 cvs 7601: attribute values. They are the <tt>Create</tt>, <tt>Write</tt>,
7602: <tt>Read</tt>, <tt>Include</tt>, <tt>Get</tt>, <tt>Copy</tt>, <tt>Use</tt>,
7603: <tt>Remove</tt>, <tt>NoTranslation</tt>, <tt>NoLineBreak</tt>,
7604: <tt>ChangeMainFile</tt>, <tt>RemoveFile</tt>, <tt>Set</tt>, <tt>Add</tt>,
7605: <tt>Indent</tt>, rules. Each rule has its own syntax, although they are all
7606: based on very similar models.</p>
7607: <pre> SimpleRule = 'Create' [ 'IN' VarID ] Object
1.1 cvs 7608: [ Position ] ';' /
7609: 'Write' Object [ Position ] ';' /
7610: 'Read' BufferID [ Position ] ';' /
7611: 'Include' File [ Position ] ';' /
7612: 'Get' [ RelPosition ] ElemID
7613: [ ExtStruct ]
7614: [ Position ] ';' /
7615: 'Copy' [ RelPosition ] ElemID
7616: [ ExtStruct ]
7617: [ Position ] ';' /
7618: 'Use' TrSchema [ 'For' ElemID ] ';' /
7619: 'Remove' ';' /
7620: 'NoTranslation' ';' /
7621: 'NoLineBreak' ';' /
7622: 'ChangeMainFile' VarID [ Position ] ';' /
1.14 cvs 7623: 'RemoveFile' VarID [ Position ] ';' /
1.10 cvs 7624: 'Set' CounterID InitValue [ Position ] ';' /
7625: 'Add' CounterID Increment [ Position ] ';' /
1.25 cvs 7626: 'Indent' [ 'IN' VarID ] Indent [ Position ] ';' .</pre>
1.18 cvs 7627: </div>
7628:
7629: <div class="subsection">
7630:
7631: <h3><a name="sectc5210">The <tt>Create</tt> rule</a></h3>
7632: <p>
7633: The most frequently used rule is undoubtedly the <tt>Create</tt> rule, which
7634: generates fixed or variable text (called an <em>object</em>) in the output
1.1 cvs 7635: file. The generated text can be made to appear either before or after the
7636: content of the element to which the rule applies. The rule begins with the
1.18 cvs 7637: <tt>Create</tt> keyword, followed by a specifier for the object and a keyword
7638: (<tt>Before</tt> or <tt>After</tt>) indicating the position of the generated
7639: text (<a href="#sectc5222">before or after</a> the element's content). If the
1.1 cvs 7640: position is not indicated, the object will be generated before the element's
7641: content. This rule, like all translation rules, is terminated by a
1.18 cvs 7642: semicolon.</p>
7643: <p>
7644: The <tt>Create</tt> keyword can be followed by the <tt>IN</tt> keyword and by
1.1 cvs 7645: the name of a variable. This means that the text generated by the rule must
7646: not be written in the main output file, but in the file whose name is
1.18 cvs 7647: specified by the variable.</p>
7648: <p>
1.1 cvs 7649: This allows the translation program to generate text in different files during
1.14 cvs 7650: the same run. These files do not need to be explicitely declared or opened.
1.18 cvs 7651: They do not need to be closed either, but if they contain temporary data, they
7652: can be removed (see the <a href="#sectc5220a"><tt>RemoveFile</tt> rule</a>).
7653: As soon as the translation program executes a <tt>Create</tt> rule for a file
7654: that is not yet open, it opens the file. These files are closed when the
7655: translation is finished.</p>
7656: <pre> 'Create' [ 'IN' VarID ] Object
1.1 cvs 7657: [ Position ] ';'
7658: Object = ConstID / CharString /
7659: BufferID /
7660: VarID /
7661: '(' Function < Function > ')' /
1.21 cvs 7662: [ 'Translated' ] AttrID /
1.1 cvs 7663: 'Value' /
7664: 'Content' /
7665: 'Comment' /
7666: 'Attributes' /
7667: 'Presentation' /
7668: 'RefId' /
7669: 'PairId' /
7670: 'FileDir' /
7671: 'FileName' /
7672: 'Extension' /
7673: 'DocumentName' /
7674: 'DocumentDir' /
7675: [ 'Referred' ] ReferredObject .
7676: Position ='After' / 'Before' .
7677:
7678: ReferredObject = VarID /
7679: ElemID [ ExtStruct ] /
7680: 'RefId' /
7681: 'DocumentName' /
1.18 cvs 7682: 'DocumentDir' .</pre>
7683: <p>
7684: The object to be generated can be:</p>
7685: <ul>
7686: <li>
7687: a constant string, specified by its name if it is declared in the schema's
7688: <tt>CONST</tt> section, or given directly as a value between apostrophes;
1.19 cvs 7689: </li>
1.18 cvs 7690: <li>
7691: the contents of a buffer, designated by the name of the buffer;
1.19 cvs 7692: </li>
1.18 cvs 7693: <li>
7694: a variable, designated by its name if it is declared in the translation
7695: schema's <tt>VAR</tt> section, or given directly between parentheses. The
7696: text generated is the value of that variable evaluated for the element to
7697: which the rule applies.
1.19 cvs 7698: </li>
1.18 cvs 7699: <li>
7700: the value of an attribute, if the element being translated has this attribute.
1.21 cvs 7701: The attribute is specified by its name. If it's a text attribute, it can be
7702: preceded by the <code>Translated</code> keyword, which causes the attribute
7703: value to be recoded using the text translation table defined by section
7704: <code><a href="#sectc5225">TEXTTRANSLATE</a></code>;
1.19 cvs 7705: </li>
1.18 cvs 7706: <li>
7707: the value of a specific presentation rule. This object can only be generated
7708: if the translation rule is for a <a href="#prestransl">specific presentation
7709: rule</a>. It is specified by the <tt>Value</tt> keyword;
1.19 cvs 7710: </li>
1.18 cvs 7711: <li>
7712: the element's content. That is, the content of the leaves of the subtree of
7713: the translated element. This is specified by the <tt>Content</tt> keyword;
1.19 cvs 7714: </li>
1.18 cvs 7715: <li>
7716: the comment attached to the element. When the element doesn't have a comment,
7717: nothing is generated. This is indicated by the <tt>Comment</tt> keyword;
1.19 cvs 7718: </li>
1.18 cvs 7719: <li>
7720: the translation of all attributes of the element (which is primarily used to
7721: apply the attribute translation rules <a href="#sectc5222">before</a> those of
7722: the element type). This is specified by the <tt>Attributes</tt> keyword.
1.19 cvs 7723: </li>
1.18 cvs 7724: <li>
7725: the translation of all of the element's specific presentation rules (which is
7726: primarily used to apply the translation rules for the specific presentation
7727: rules <a href="#sectc5222">before</a> those of the element or its attributes).
7728: This option is specified by the <tt>Presentation</tt> keyword;
1.19 cvs 7729: </li>
1.18 cvs 7730: <li>
7731: The value of the reference's identifier.<br>
7732: Thot associates a unique identifier with each element in a document. This
7733: identifier (called <em>reference's identifier</em> or <em>label</em>) is a
7734: character string containing the letter `L' followed by digits. Thot uses it
7735: in references for identifying the referred element.<br>
7736: The <tt>RefId</tt> keyword produces the reference's identifier of the element
7737: to which the translation rule is applied, or the reference's identifier of its
7738: first ancestor that is referred by a reference or that can be referred by a
7739: reference.
1.19 cvs 7740: </li>
1.18 cvs 7741: <li>
7742: the value of a mark pair's unique identifier. This may only be used for <a
7743: href="#sectd3285">mark pairs</a> and is indicated by the <tt>PairId</tt>
1.2 cvs 7744: keyword.
1.19 cvs 7745: </li>
1.18 cvs 7746: <li>
7747: the directory containing the file being generated (this string includes an
7748: ending '/', if it is not empty). This is indicated by the <tt>FileDir</tt>
1.2 cvs 7749: keyword.
1.19 cvs 7750: </li>
1.18 cvs 7751: <li>
7752: the name of the file being generated (only the name, without the directory and
7753: without the extension). This is indicated by the <tt>FileName</tt> keyword.
1.19 cvs 7754: </li>
1.18 cvs 7755: <li>
7756: the extension of the file being generated (this string starts with a dot, if
7757: it is not empty). This is indicated by the <tt>Extension</tt> keyword.
1.19 cvs 7758: </li>
1.18 cvs 7759: <li>
7760: the name of the document being translated. This is indicated by the
7761: <tt>DocumentName</tt> keyword.
1.19 cvs 7762: </li>
1.18 cvs 7763: <li>
7764: the directory containing the document being translated. This is indicated by
7765: the <tt>DocumentDir</tt> keyword.
1.19 cvs 7766: </li>
1.18 cvs 7767: </ul>
7768: <p>
1.1 cvs 7769: When the rule applies to a reference (an element or an attribute defined as a
7770: reference in the structure schema), it can generate a text related to the
1.21 cvs 7771: element referred by that reference. The rule name is then followed by the
1.18 cvs 7772: <tt>Referred</tt> keyword and a specification of the object to be generated
7773: for the referred element. This specification can be:</p>
7774: <ul>
7775: <li>
7776: the name of a variable. The rule generates the value of that variable,
1.1 cvs 7777: computed for the referred element.
1.19 cvs 7778: </li>
1.18 cvs 7779: <li>
7780: an element type. The rule generates the translation of the element of that
7781: type, which is in the subtree of the referred element. If this element is not
7782: defined in the structure schema which corresponds to the translation schema
7783: (that is, an object defined in another schema), the element's type name must
7784: be followed by the name of its structure schema between parentheses.
1.19 cvs 7785: </li>
1.18 cvs 7786: <li>
7787: the <tt>RefId</tt> keyword. The rule generates the reference's identifier of
7788: the referred element.
1.19 cvs 7789: </li>
1.18 cvs 7790: <li>
7791: the <tt>DocumentName</tt> keyword. The rule generates the name of the
1.1 cvs 7792: document to which the referred element belongs.
1.19 cvs 7793: </li>
1.18 cvs 7794: <li>
7795: the <tt>DocumentDir</tt> keyword. The rule generates the name of the
1.1 cvs 7796: directory that contains the document of the referred element.
1.19 cvs 7797: </li>
1.18 cvs 7798: </ul>
7799: </div>
1.1 cvs 7800:
1.18 cvs 7801: <div class="subsection">
1.1 cvs 7802:
1.18 cvs 7803: <h3><a name="sectc5211">The <tt>Write</tt> rule</a></h3>
7804: <p>
7805: The <tt>Write</tt> has the same syntax as the <tt>Create</tt> rule. It also
1.1 cvs 7806: produces the same effect, but the generated text is displayed on the user's
7807: terminal during the translation of the document, instead of being produced in
7808: the translated document. This is useful for helping the user keep track of
7809: the progress of the translation and for prompting the user on the terminal for
1.18 cvs 7810: input required by the <tt>Read</tt> rule.</p>
7811: <pre> 'Write' Object [ Position ] ';'</pre>
7812: <p>
1.1 cvs 7813: Notice: if the translator is launched by the editor (by the ``Save as''
1.18 cvs 7814: command), messages produced by the <tt>Write</tt> rule are not displayed.</p>
7815: <blockquote class="example">
7816: <p>
7817: <strong>Example:</strong></p>
7818: <p>
1.3 cvs 7819: To make the translator display the number of each section being translated on
1.18 cvs 7820: the user's terminal, the following rule is specified for the <tt>Section</tt>
7821: element type:</p>
7822: <pre>Section : BEGIN
1.1 cvs 7823: Write VarSection;
7824: ...
1.18 cvs 7825: END;</pre>
7826: <p>
7827: (see <a href="#varsectexample">above</a> for the definition of the
7828: <tt>VarSection</tt> variable).</p>
7829: <p>
1.1 cvs 7830: To display text on the terminal before issuing a read operation with the
1.18 cvs 7831: <tt>Read</tt> rule, the following rule is used:</p>
7832: <pre>BEGIN
1.1 cvs 7833: Write 'Enter the name of the destination: ';
7834: ...
1.18 cvs 7835: END;</pre>
7836: </blockquote>
7837: </div>
7838:
7839: <div class="subsection">
7840:
7841: <h3><a name="sectc5212">The <tt>Read</tt> rule</a></h3>
7842: <p>
7843: The <tt>Read</tt> rule reads text from the terminal during the translation of
1.1 cvs 7844: the document and saves the text read in one of the buffers declared in the
1.18 cvs 7845: <tt>BUFFERS</tt> section of the schema. The buffer to be used is indicated by
7846: its name, after the <tt>READ</tt> keyword. This name can be followed, as in
7847: the <tt>Create</tt> and <tt>Write</tt> rules, by a keyword indicating if the
7848: read operation must be performed <tt>Before</tt> or <tt>After</tt> the
1.1 cvs 7849: translation of the element's content. If this keyword is absent, the read
7850: operation is done beforehand. The text is read into the buffer and remains
1.5 cvs 7851: there until a rule using the same buffer - possibly the same rule - is
1.18 cvs 7852: applied.</p>
7853: <pre> 'Read' BufferID [ Position ] ';'</pre>
7854: <blockquote class="example">
7855: <p>
7856: <strong>Example:</strong></p>
7857: <p>
1.3 cvs 7858: The following set of rules tells the user that the translator is waiting for
7859: the entry of some text, reads this text into a buffer and copies the text into
1.18 cvs 7860: the translated document.</p>
7861: <pre>BEGIN
1.1 cvs 7862: Write 'Enter the name of the destination: ';
7863: Read DestName;
7864: Create DestName;
7865: ...
1.18 cvs 7866: END;</pre>
7867: <p>
7868: (see <a href="#destname">above</a> the definition of <tt>DestName</tt>).</p>
7869: </blockquote>
7870: </div>
7871:
7872: <div class="subsection">
7873:
7874: <h3><a name="sectc5213">The <tt>Include</tt> rule</a></h3>
7875: <p>
7876: The <tt>Include</tt> rule, like the <tt>Create</tt> rule, is used to produce
1.1 cvs 7877: text in the translated document. It inserts constant text which is not
7878: defined in the translation schema, but is instead taken from a file. The
1.18 cvs 7879: file's name is specified after the <tt>Include</tt> keyword, either directly
1.1 cvs 7880: as a character string between apostrophes or as the name of one of the buffers
1.18 cvs 7881: declared in the <tt>BUFFERS</tt> section of the schema. In the latter case,
1.1 cvs 7882: the buffer is assumed to contain the file's name. This can be used when the
7883: included file's name is known only at the moment of translation. This only
1.18 cvs 7884: requires that the <tt>Include</tt> rule is preceded by a <tt>Read</tt> rule
7885: which puts the name of the file desired by the user into the buffer.</p>
7886: <p>
1.1 cvs 7887: Like the other rules, it is possible to specify whether the inclusion will
7888: occur before or after the element's content, with the default being before.
7889: The file inclusion is only done at the moment of translation, not during the
7890: compilation of the translation schema. Thus, the file to be included need not
7891: exist during the compilation, but it must be accessible at the time of
7892: translation. Its contents can also be modified between two translations, thus
7893: producing different results, even if neither the document or the translation
1.18 cvs 7894: schema are modified.</p>
7895: <p>
1.1 cvs 7896: During translation, the file to be included is searched for along the schema
1.18 cvs 7897: directory path (indicated by the environment variable <tt>THOTSCH</tt>). The
1.1 cvs 7898: file name is normally only composed of a simple name, without specification of
1.12 cvs 7899: a complete file path. However, if the filename starts with a '/', it is
1.18 cvs 7900: considered as an absolute path.</p>
7901: <pre> 'Include' File [ Position ] ';'
1.6 cvs 7902: File = FileName / BufferID .
1.18 cvs 7903: FileName = STRING .</pre>
7904: <blockquote class="example">
7905: <p>
7906: <strong>Example:</strong></p>
7907: <p>
1.3 cvs 7908: Suppose that it is desirable to print documents of the Article class with a
7909: formatter which requires a number of declarations and definitions at the
1.18 cvs 7910: beginning of the file. The <tt>Include</tt>rule can be used to achieve this.
1.3 cvs 7911: All the declarations and definitions a replaced in a file called
1.18 cvs 7912: <tt>DeclarArt</tt> and then the <tt>Article</tt> element type is given the
7913: following rule:</p>
7914: <pre>Article : BEGIN
1.1 cvs 7915: Include 'DeclarArt' Before;
7916: ...
1.18 cvs 7917: END;</pre>
7918: </blockquote>
7919: </div>
7920:
7921: <div class="subsection">
7922:
7923: <h3><a name="sectc5214">The <tt>Get</tt> rule</a></h3>
7924: <p>
7925: The <tt>Get</tt> rule is used to change the order in which the elements appear
1.1 cvs 7926: in the translated document. More precisely, it produces the translation of a
7927: specified element before or after the translation of the content of the
1.18 cvs 7928: element to which the rule applies. The <tt>Before</tt> and <tt>After</tt>
1.1 cvs 7929: keywords are placed at the end of the rule to specify whether the operation
7930: should be performed before or after translation of the rule's element (the
7931: default is before). The type of the element to be moved must be specified
1.18 cvs 7932: after the <tt>Get</tt> keyword, optionally preceded by a keyword indicating
7933: where the element will be found in the logical structure of the document:</p>
7934: <dl>
7935: <dt><tt>Included</tt></dt>
7936: <dd>
7937: The element to be moved is the first element of the indicated type which is
1.1 cvs 7938: found inside the element to which the rule applies.
1.18 cvs 7939: </dd>
7940: <dt><tt>Referred</tt></dt>
7941: <dd>
7942: This keyword can only be used if the rule applies to a reference element. The
7943: element to be moved is either the element designated by the reference (if that
7944: element is of the specified type), or the first element of the desired type
7945: contained within the element designated by the reference.
7946: </dd>
7947: <dt>no keyword</dt>
7948: <dd>
7949: If the element to be moved is an associated element, defined in the <a
7950: href="#sectc314"><tt>ASSOC</tt> section</a> of the structure schema, all
1.2 cvs 7951: associated elements of this type which have not been translated yet are then
7952: translated. Certain elements may in fact have already been translated by a
1.18 cvs 7953: <tt>Get Referred</tt> rule.
7954: <p>
1.1 cvs 7955: If the element to be moved is not an associated element, the translator takes
7956: the first element of the indicated type from among the siblings of the rule's
7957: element. This is primarily used to change the order of the components of an
1.18 cvs 7958: aggregate.</p>
7959: </dd>
7960: </dl>
7961: <p>
1.1 cvs 7962: If the element to be moved is defined in a structure schema which is not the
7963: one which corresponds to the translation schema (in the case of an included
7964: object with a different schema), the type name of this element must be
7965: followed, between parentheses, by the name of the structure schema which
1.18 cvs 7966: defines it.</p>
7967: <pre> 'Get' [ RelPosition ] ElemID
1.6 cvs 7968: [ ExtStruct ]
7969: [ Position ] ';' /
7970: RelPosition = 'Included' / 'Referred' .
1.18 cvs 7971: ExtStruct = '(' ElemID ')' .</pre>
7972: <p>
7973: The <tt>Get</tt> rule has no effect if the element which it is supposed to
1.1 cvs 7974: move has already been translated. Thus, the element will not be duplicated.
7975: It is generally best to associate the rule with the first element which will
7976: be encountered by the translator in its traversal of the document. Suppose an
1.18 cvs 7977: aggregate has two elements <tt>A</tt> and <tt>B</tt>, with <tt>A</tt>
1.1 cvs 7978: appearing first in the logical structure. To permute these two elements, a
1.18 cvs 7979: <tt>Get B before</tt> rule should be associated with the <tt>A</tt> element
7980: type, not the inverse. Similarly, a rule of the form <tt>Get Included X
7981: After</tt>, even though syntactically correct, makes no sense since, by the
1.1 cvs 7982: time it will be applied, after the translation of the contents of the element
1.18 cvs 7983: to which it is attached, the <tt>X</tt> element will already have been
7984: translated.</p>
7985: <p>
7986: The <tt>Get</tt> rule is the only way to obtain the translation of the
1.1 cvs 7987: associated elements. In fact, the translator only traverses the primary tree
7988: of the document and thus does not translate the associated elements, except
1.18 cvs 7989: when the translation is explicitly required by a <tt>Get Referred Type</tt> or
7990: <tt>Get Type</tt> rule where <tt>Type</tt> is an associated element type.</p>
7991: <blockquote class="example">
7992: <p>
7993: <strong>Example:</strong></p>
7994: <p>
1.3 cvs 7995: The structure schema defined figures as associated element which are composed
7996: of some content and a caption. Moreover, it is possible to make references to
1.18 cvs 7997: figures, using elements of the <tt>RefFigure</tt> type:</p>
7998: <pre> ...
1.1 cvs 7999: RefFigure = REFERENCE(Figure);
8000: ASSOC
1.6 cvs 8001: Figure = BEGIN
8002: Content = NATURE;
8003: Caption = Text;
8004: END;
1.18 cvs 8005: ...</pre>
8006: <p>
1.3 cvs 8007: Suppose it would be useful to make a figure appear in the translated document
8008: at the place in the text where the first reference to the figure is made. If
8009: some figures are not referenced, then they would appear at the end of the
8010: document. Also, each figure's caption should appear before the content. The
1.18 cvs 8011: following rules in the translation schema will produce this result:</p>
8012: <pre>Article : BEGIN
1.1 cvs 8013: ...
8014: Get Figures After;
8015: END;
8016: RefFigure : BEGIN
8017: If FirstRef Get Referred Figure;
8018: ...
8019: END;
8020: Content : BEGIN
8021: Get Caption Before;
8022: ...
1.18 cvs 8023: END;</pre>
8024: </blockquote>
8025: </div>
8026:
8027: <div class="subsection">
8028:
8029: <h3><a name="sectc5215">The <tt>Copy</tt> rule</a></h3>
8030: <p>
8031: Like the <tt>Get</tt> rule, the <tt>Copy</tt> rule generates the translation
1.1 cvs 8032: of a specified element, but it acts even if the element has already been
8033: translated and it allows to copy it or to translate it later. Both rules have
1.18 cvs 8034: the same syntax.</p>
8035: <pre> 'Copy' [ RelPosition ] ElemID
8036: [ ExtStruct ] [ Position ] ';'</pre>
8037: </div>
8038:
8039: <div class="subsection">
8040:
8041: <h3><a name="sectc5216">The <tt>Use</tt> rule</a></h3>
8042: <p>
8043: The <tt>Use</tt> rule specifies the translation schema to be applied to
1.1 cvs 8044: objects of a certain class that are part of the document. This rule only
8045: appears in the rules for the root element of the document (the first type
1.18 cvs 8046: defined after the <tt>STRUCT</tt> keyword in the structure schema) or the
1.1 cvs 8047: rules of an element defined by an external structure (by another structure
1.18 cvs 8048: schema). Also, the <tt>Use</tt> rule cannot be conditional.</p>
8049: <p>
1.1 cvs 8050: If the rule is applied to an element defined by an external structure, the
1.18 cvs 8051: <tt>Use</tt> keyword is simply followed by the name of the translation schema
1.1 cvs 8052: to be used for element constructed according to that external structure. If
8053: the rule is applied to the document's root element, it is formed by the
1.18 cvs 8054: <tt>Use</tt> keyword followed by the translation schema's name, the
8055: <tt>For</tt> keyword and the name of the external structure to which the
8056: indicated translation schema should be applied.</p>
8057: <pre> 'Use' TrSchema [ 'For' ElemID ] ';'
8058: TrSchema = NAME .</pre>
8059: <p>
8060: If no <tt>Use</tt> rule defines the translation schema to be used for an
1.1 cvs 8061: external structure which appears in a document, the translator asks the user,
8062: during the translation process, which schema should be used. Thus, it is not
1.18 cvs 8063: necessary to give the translation schema a <tt>Use</tt> rule for every
1.1 cvs 8064: external structure used, especially when the choice of translation schemas is
1.18 cvs 8065: to be left to the user.</p>
8066: <p>
1.1 cvs 8067: Notice: if the translator is launched by the editor (by the ``Save as''
1.18 cvs 8068: command), prompts are not displayed.</p>
8069: <blockquote class="example">
8070: <p>
8071: <strong>Example:</strong></p>
8072: <p>
8073: The <tt>Article</tt> structure schema uses the <tt>Formula</tt> external
8074: structure, defined by another structure schema, for mathematical formulas:</p>
8075: <pre>STRUCTURE Article;
1.1 cvs 8076: ...
8077: STRUCT
8078: Article = ...
8079: ...
8080: Formula_in_text = Formula;
8081: Isolated_formula = Formula;
8082: ...
1.18 cvs 8083: END</pre>
8084: <p>
8085: Suppose that it would be useful to use the <tt>FormulaT</tt> translation
8086: schema for the formulas of an article. This can be expressed in two different
8087: ways in the <tt>Article</tt> class translation schema, using the rules:</p>
8088: <pre>RULES
1.1 cvs 8089: Article :
1.18 cvs 8090: Use FormulaT for Formula;</pre>
8091: <p>
8092: or:</p>
8093: <pre>RULES
1.1 cvs 8094: ...
8095: Formula :
1.18 cvs 8096: Use FormulaT;</pre>
8097: </blockquote>
8098: </div>
8099:
8100: <div class="subsection">
8101:
8102: <h3><a name="sectc5217">The <tt>Remove</tt> rule</a></h3>
8103: <p>
8104: The <tt>Remove</tt> rule indicates that nothing should be generated, in the
1.1 cvs 8105: translated document, for the content of the element to which the rule applies.
8106: The content of that element is simply ignored by the translator. This does
8107: not prevent the generation of text for the element itself, using the
1.18 cvs 8108: <tt>Create</tt> or <tt>Include</tt> rules, for example.</p>
8109: <p>
8110: The <tt>Remove</tt> rule is simply written with the <tt>Remove</tt> keyword.
8111: It is terminated, like all rules, by a semicolon.</p>
8112: <pre> 'Remove' ';'</pre>
8113: </div>
8114:
8115: <div class="subsection">
8116:
8117: <h3><a name="sectc5218">The <tt>NoTranslation</tt> rule</a></h3>
8118: <p>
8119: The <tt>NoTranslation</tt> rule indicates to the translator that it must not
1.1 cvs 8120: translate the content of the leaves of the element to which it applies. In
1.18 cvs 8121: contrast to the <tt>Remove</tt> rule, it does not suppress the content of the
1.1 cvs 8122: element, but it inhibits the translation of character strings, symbols, and
8123: graphical elements contained in the element. These are retrieved so that
1.18 cvs 8124: after the translation of the document, the rules of the <a
8125: href="#sectc5225"><tt>TEXTTRANSLATE</tt>, <tt>SYMBTRANSLATE</tt> and
8126: <tt>GRAPHTRANSLATE</tt> sections</a> will not be applied to them.</p>
8127: <p>
8128: The <tt>NoTranslation</tt> rule is written with the <tt>NoTranslation</tt>
8129: keyword followed by a semicolon.</p>
8130: <pre> 'NoTranslation' ';'</pre>
8131: </div>
8132:
8133: <div class="subsection">
8134:
8135: <h3><a name="sectc5219">The <tt>NoLineBreak</tt> rule</a></h3>
8136: <p>
8137: The <tt>NoLineBreak</tt> rule indicates to the translator that it must not
1.1 cvs 8138: generate additional line breaks in the output produced for the element to
1.18 cvs 8139: which it applies. This is as if it was an <a href="#sectc522">instruction
8140: <tt>LINELENGTH 0;</tt></a> at the beginning of the translation schema, but
8141: only for the current element.</p>
8142: <p>
8143: The <tt>NoLineBreak</tt> rule is written with the <tt>NoLineBreak</tt> keyword
8144: followed by a semicolon.</p>
8145: <pre> 'NoLineBreak' ';'</pre>
8146: </div>
1.1 cvs 8147:
1.18 cvs 8148: <div class="subsection">
1.1 cvs 8149:
1.18 cvs 8150: <h3><a name="sectc5220">The <tt>ChangeMainFile</tt> rule</a></h3>
8151: <p>
1.1 cvs 8152: When the translation program starts, it opens a main output file, whose name
1.18 cvs 8153: is given as a parameter of the translator. All <a
8154: href="#sectc5210"><tt>Create</tt> rules</a> without explicit indication of the
8155: output file write sequentially in this file. When a <tt>ChangeMainFile</tt>
8156: rule is executed, the main output file is closed and it is replaced by a new
8157: one, whose name is specified in the <tt>ChangeMainFile</tt> rule. The
8158: <tt>Create</tt> rules without indication of the output file that are then
8159: executed write in this new file. Several <tt>ChangeMainFile</tt> rules can be
8160: executed during the same translation, for dividing the main output into
8161: several files.</p>
8162: <p>
8163: This rule is written with the <tt>ChangeMainFile</tt> keyword followed by the
1.14 cvs 8164: name of a variable that specifies the name of the new main file. The keyword
1.18 cvs 8165: <tt>Before</tt> or <tt>After</tt> can be placed at the end of the rule to
1.1 cvs 8166: specify whether the operation should be performed before or after translation
8167: of the rule's element (the default is before). This rule, like all translation
1.18 cvs 8168: rules, is terminated by a semicolon.</p>
8169: <pre> 'ChangeMainFile' VarID [ Position ] ';'</pre>
8170: <blockquote class="example">
8171: <p>
8172: <strong>Example:</strong></p>
8173: <p>
1.3 cvs 8174: To generate the translation of each section in a different file, the following
1.18 cvs 8175: rule can be associated with type <tt>Section</tt>. That rule uses the <a
8176: href="#varoutputfile"><tt>VarOutpuFile</tt> variable</a> defined above.</p>
8177: <pre> Section:
8178: ChangeMainFile VarOutpuFile Before;</pre>
8179: <p>
8180: If <tt>output.txt</tt> is the name of the output file specified when starting
1.3 cvs 8181: the translation program, translated sections are written in files
1.18 cvs 8182: <tt>output1.txt</tt>, <tt>output2.txt</tt>, etc.</p>
8183: </blockquote>
8184: </div>
1.1 cvs 8185:
1.18 cvs 8186: <div class="subsection">
1.14 cvs 8187:
1.18 cvs 8188: <h3><a name="sectc5220a">The <tt>RemoveFile</tt> rule</a></h3>
8189: <p>
1.14 cvs 8190: Files may be used for storing temporary data that are no longer needed when
1.18 cvs 8191: the translation of a document is complete. These files may be removed by the
8192: <tt>RemoveFile</tt> rule.</p>
8193: <p>
8194: This rule is written with the <tt>RemoveFile</tt> keyword followed by the name
8195: of a variable that specifies the name of the file to be removed. The keyword
8196: <tt>Before</tt> or <tt>After</tt> can be placed at the end of the rule to
8197: specify whether the operation should be performed before or after translation
8198: of the rule's element (the default is before). This rule, like all
8199: translation rules, is terminated by a semicolon.</p>
8200: <pre> 'RemoveFile' VarID [ Position ] ';'</pre>
8201: </div>
8202:
8203: <div class="subsection">
8204:
8205: <h3><a name="sectc5221">The <tt>Set</tt> and <tt>Add</tt> rules</a></h3>
8206: <p>
8207: The <tt>Set</tt> and <tt>Add</tt> rules are used for modifying the value of
8208: counters that have no <a href="#sectc524">counting function</a>. Only this
8209: type of counter can be used in the <tt>Set</tt> and <tt>Add</tt> rules.</p>
8210: <p>
8211: Both rules have the same syntax: after the keyword <tt>Set</tt> or
8212: <tt>Add</tt> appear the counter name and the value to assign to the counter
8213: (<tt>Set</tt> rule) or the value to be added to the counter (<tt>Add</tt>
8214: rule). The keyword <tt>Before</tt> or <tt>After</tt> can follow that value to
1.1 cvs 8215: indicate when the rule must be applied: before or after the element's content
1.18 cvs 8216: is translated. By default, <tt>Before</tt> is assumed. A semicolon terminates
8217: the rule.</p>
8218: <pre> 'Set' CounterID InitValue [ Position ] ';' /
8219: 'Add' CounterID Increment [ Position ] ';'</pre>
8220: </div>
8221:
8222: <div class="subsection">
8223:
8224: <h3><a name="sectc5221a">The <tt>Indent</tt> rule</a></h3>
8225: <p>
8226: The <tt>Indent</tt> rule is used to modify the value of text indentation in
8227: the output files.</p>
8228: <p>
8229: Each time the translator creates a new line in an output file, it generates a
8230: variable number of space characters at the beginning of the new line. By
1.25 cvs 8231: default, the number of these characters (the indentation value) is 0. It can
8232: be changed with the <tt>Indent</tt> rule.</p>
1.18 cvs 8233: <p>
1.25 cvs 8234: In its simple form, the rule begins with the <tt>Indent</tt> keyword,
8235: followed by the indentation sign (optional) and value and a keyword
8236: <tt>Before</tt> or <tt>After</tt> indicating that the indentation should
8237: be changed <a href="#sectc5222">before or after</a> the element's content
8238: is generated. If the position is not indicated, the indentation is changed
8239: before the element's content is generated. This rule, like all translation
8240: rules, is terminated by a semicolon.</p>
1.18 cvs 8241: <p>
8242: The indentation value is indicated by an integer, which is the number of space
8243: characters to be generated at the beginning of each new line. A sign
8244: (<tt>+</tt> or <tt>-</tt>) can appear before the integer to indicate that the
8245: value is relative: the current value of indentation is incremented (if sign is
8246: <tt>+</tt>) or decremented (if sign is <tt>-</tt>) by the specified value.</p>
8247: <p>
1.25 cvs 8248: Keyword <tt>Suspend</tt> or <tt>Resume</tt> can appear instead of the
8249: (possibly signed) identation value. <tt>Suspend</tt> means that the new
8250: indentation value to be used is zero until another <tt>Indent</tt> rule
8251: is executed and changes the indentation value. <tt>Resume</tt> means that
8252: the indentation value that was used before the last <tt>Indent Suspend</tt>
8253: was executed becomes the new value. Only one <tt>Suspend</tt> can be used
8254: before a <tt>Resume</tt>; <tt>Supend</tt>-<tt>Resume</tt> pairs can not be
8255: nested.
8256: <p>
1.18 cvs 8257: Like the <a href="#sectc5210"><tt>Create</tt> rule</a>, the <tt>Indent</tt>
8258: keyword can be followed by the <tt>IN</tt> keyword and by the name of a <a
8259: href="#sectc526">variable</a>. This means that the rule must not change
1.10 cvs 8260: indentation in the main output file, but in the file whose name is specified
8261: by the variable (by default, indentation is changed in the main output
1.18 cvs 8262: file).</p>
1.25 cvs 8263: <pre> 'Indent' [ 'IN' VarID ] Indent [ Position ] ';' .
1.10 cvs 8264:
1.25 cvs 8265: Indent = 'Suspend' / 'Resume' / [ IndentSign ] IndentValue .
1.10 cvs 8266: IndentSign = '+' / '-' .
1.18 cvs 8267: IndentValue = NUMBER .</pre>
8268: </div>
1.10 cvs 8269:
1.18 cvs 8270: <div class="subsection">
1.1 cvs 8271:
1.18 cvs 8272: <h3><a name="sectc5222">Rule application order</a></h3>
8273: <p>
1.1 cvs 8274: The translator translates the elements which comprise the document in the
1.18 cvs 8275: order induced by the tree structure, except when the <tt>Get</tt> rule is used
1.1 cvs 8276: to change the order of translation. For each element, the translator first
8277: applies the rules specified for the element's type that must be applied before
1.18 cvs 8278: translation of the element's content (rules ending with the <tt>Before</tt>
1.1 cvs 8279: keyword or which have no position keyword). If several rules meet these
8280: criteria, the translator applies them in the order in where they appear in the
1.18 cvs 8281: translation schema.</p>
8282: <p>
8283: It then applies all <a href="#sectc5223">rules for the attributes</a> which
1.1 cvs 8284: the element has and which must be applied before the translation of the
1.18 cvs 8285: element's content (rules ending with the <tt>Before</tt> keyword or which have
1.1 cvs 8286: no position keyword). For one attribute value, the translator applies the
1.18 cvs 8287: rules in the order in which they are defined in the translation schema.</p>
8288: <p>
1.1 cvs 8289: The same procedure is followed with translation rules for specific
1.18 cvs 8290: presentations.</p>
8291: <p>
8292: Next, the element's content is translated, as long as a <tt>Remove</tt> rule
8293: does not apply.</p>
8294: <p>
1.1 cvs 8295: In the next step, the translator applies rules for the specific presentation
8296: of the element that are to be applied after translation of the content (rules
1.18 cvs 8297: which end with the <tt>After</tt> keyword). The rules for each type of
1.1 cvs 8298: presentation rule or each value are applied in the order in which the
1.18 cvs 8299: translation appear in the schema.</p>
8300: <p>
1.1 cvs 8301: Then, the same procedure is followed for translation rules for attributes of
1.18 cvs 8302: the element.</p>
8303: <p>
1.1 cvs 8304: Finally, the translator applies rules for the element which must be applied
8305: after translation of the element's content. These rules are applied in the
8306: order that they appear in the translation schema. When the translation of an
8307: element is done, the translator procedes to translate the following
1.18 cvs 8308: element.</p>
8309: <p>
8310: This order can be changed with the <tt>Attributes</tt> and
8311: <tt>Presentation</tt> options of the <a href="#sectc5210"><tt>Create</tt>
8312: rule</a>.</p>
8313: </div>
1.1 cvs 8314:
1.18 cvs 8315: <div class="subsection">
1.1 cvs 8316:
1.18 cvs 8317: <h3><a name="sectc5223">Translation of logical attributes</a></h3>
8318: <p>
1.1 cvs 8319: After the rules for the element types, the translation schema defines rules
1.18 cvs 8320: for attribute values. This section begins with the <tt>ATTRIBUTES</tt>
1.1 cvs 8321: keyword and is composed of a sequence of rule blocks each preceded by an
1.18 cvs 8322: attribute name and an optional value or value range.</p>
8323: <p>
1.1 cvs 8324: If the attribute's name appears alone before the rule block, the rule are
8325: applied to all element which have the attribute, no matter what value the
8326: attribute has. In this case, the attribute name is followed by a colon before
1.18 cvs 8327: the beginning of the rule block.</p>
8328: <p>
1.1 cvs 8329: The attribute's name can be followed by the name of an element type between
8330: parentheses. This says, as in presentation schemas, that the rule block which
8331: follows applies not to the element which has the attribute, but to its
1.18 cvs 8332: descendants of the type indicated between the parentheses.</p>
8333: <p>
1.1 cvs 8334: If values are given after the attribute name (or after the name of the element
8335: type), the rules are applied only when the attribute has the indicated values.
8336: The same attribute can appear several times, with different values and
8337: different translation rules. Attribute values are indicated in the same way
1.18 cvs 8338: as in <a href="#sectc528">conditions</a> and are followed by a colon before
8339: the block of rules.</p>
8340: <p>
1.1 cvs 8341: The rule block associated with an attribute is either a simple rule or a
1.18 cvs 8342: sequence of rules delimited by the <tt>BEGIN</tt> and <tt>END</tt> keywords.
8343: Note that rules associated with attribute values cannot be conditional.</p>
8344: <p>
1.1 cvs 8345: Translation rules are not required for all attributes (or their values)
8346: defined in a structure schema. Only those attributes for which a particular
8347: action must be performed by the translator must have such rules. The rules
1.18 cvs 8348: that can be used are those described above, from <a
8349: href="#sectc5210"><tt>Create</tt></a> to <a
8350: href="#sectc5218"><tt>NoTranslation</tt></a>.</p>
8351: <pre> AttrSeq = TransAttr < TransAttr > .
1.1 cvs 8352: TransAttr = AttrID [ '(' ElemID ')' ]
8353: [ RelatAttr ] ':' RuleSeq .
8354: AttrID = NAME .
1.18 cvs 8355: ElemID = NAME .</pre>
8356: <blockquote class="example">
8357: <p>
8358: <strong>Example:</strong></p>
8359: <p>
1.3 cvs 8360: The structure defined the ``Language'' attribute which can take the values
8361: ``French'' and ``English''. To have the French parts of the original document
8362: removed and prevent the translation of the leaves of the English parts, the
1.18 cvs 8363: following rules would be used:</p>
8364: <pre>ATTRIBUTES
1.1 cvs 8365: Language=French :
8366: Remove;
8367: Language=English :
1.18 cvs 8368: NoTranslation;</pre>
8369: </blockquote>
8370: </div>
1.1 cvs 8371:
1.18 cvs 8372: <div class="subsection">
1.1 cvs 8373:
1.18 cvs 8374: <h3><a name="sectc5224">Translation of specific presentations</a></h3>
8375: <p>
1.1 cvs 8376: After the rules for attributes, the translation schema defines rules for the
1.18 cvs 8377: specific presentation. This section begins with the <tt>PRESENTATION</tt>
1.1 cvs 8378: keyword and is composed of a sequence of translation rule blocks each preceded
8379: by a presentation rule name, optionally accompanied by a part which depends on
1.18 cvs 8380: the particular presentation rule.</p>
8381: <p>
1.1 cvs 8382: Each of these translation rule blocks is applied when the translator operates
8383: on an element which has a specific presentation rule of the type indicated at
8384: the head of the block. Depending on the type of the specific presentation
8385: rule, it is possible to specify values of the presentation rule for which the
1.18 cvs 8386: translation rule block should be applied.</p>
8387: <p>
8388: There are three categories of the presentation rules:</p>
8389: <ul>
8390: <li>
8391: rules taking numeric values: <tt>Size</tt>, <tt>Indent</tt>,
8392: <tt>LineSpacing</tt>, <tt>LineWeight</tt>,
1.19 cvs 8393: </li>
1.18 cvs 8394: <li>
8395: rules whose values are taken from a predefined list (i.e. whose type is an
8396: enumeration): <tt>Adjust</tt>, <tt>Justify</tt>, <tt>Hyphenate,/TT>,
1.24 cvs 8397: <tt>Style</tt>, <tt>Weight</tt>, <tt>Font</tt>, <tt>UnderLine</tt>,
8398: <tt>Thickness</tt>, <tt>LineStyle</tt>,</tt>
1.19 cvs 8399: </li>
1.18 cvs 8400: <li>
8401: rules whose value is a name: <tt>FillPattern</tt>, <tt>Background</tt>,
8402: <tt>Foreground</tt>.
1.19 cvs 8403: </li>
1.18 cvs 8404: </ul>
8405: <p>
1.1 cvs 8406: For presentation rules of the first category, the values which provoke
8407: application of the translation rules are indicated in the same manner as for
1.18 cvs 8408: <a href="#relattr">numeric attributes</a>. This can be either a unique value
1.1 cvs 8409: or range of values. For a unique value, the value (an integer) is simply
8410: preceded by an equals sign. Value ranges can be specified in one of three
1.18 cvs 8411: ways:</p>
8412: <ul>
8413: <li>
8414: all values less than a given value (this value is preceded by a ``less than''
8415: sign '<tt><</tt>'),
1.19 cvs 8416: </li>
1.18 cvs 8417: <li>
8418: all values greater than a given value (this value is preceded by a` `greater
8419: than'' sign '<tt>></tt>'),
1.19 cvs 8420: </li>
1.18 cvs 8421: <li>
8422: all values falling in an interval, bounds included. The range of values is
8423: then specified <tt>IN [</tt>Minimum<tt>..</tt>Maximum<tt>]</tt>, where Minimum
8424: and Maximum are integers.
1.19 cvs 8425: </li>
1.18 cvs 8426: </ul>
8427: <p>
1.2 cvs 8428: All numeric values can be negative, in which case the integer is preceded by a
1.18 cvs 8429: minus sign. All values must be given in typographers points.</p>
8430: <p>
1.1 cvs 8431: For presentation rules whose values are taken from a predefined list, the
8432: value which provokes application of the translation rules is simply indicated
1.18 cvs 8433: by the equals sign followed by the name of the value.</p>
8434: <p>
1.1 cvs 8435: For presentation rules whose values are names, the value which provokes the
8436: application of translation rules is simply indicated by the equals sign
8437: followed by the name of the value. The names of the fill patterns (the
1.18 cvs 8438: <tt>FillPattern</tt> rule) and of the colors (the <tt>Foreground</tt> and
8439: <tt>Background</tt> rules) used in Thot are the same as in the P language.</p>
8440: <pre> PresSeq = PresTrans < PresTrans > .
1.1 cvs 8441: PresTrans = PresRule ':' RuleSeq .
8442: PresRule = 'Size' [ PresRelation ] /
8443: 'Indent' [ PresRelation ] /
8444: 'LineSpacing' [ PresRelation ] /
8445: 'Adjust' [ '=' AdjustVal ] /
8446: 'Justify' [ '=' BoolVal ] /
8447: 'Hyphenate' [ '=' BoolVal ] /
8448: 'Style' [ '=' StyleVal ] /
1.24 cvs 8449: 'Weight' [ '=' WeightVal ] /
1.1 cvs 8450: 'Font' [ '=' FontVal ] /
8451: 'UnderLine' [ '=' UnderLineVal ] /
8452: 'Thickness' [ '=' ThicknessVal ] /
8453: 'LineStyle' [ '=' LineStyleVal ] /
8454: 'LineWeight' [ PresRelation ] /
8455: 'FillPattern' [ '=' Pattern ] /
8456: 'Background' [ '=' Color ] /
8457: 'Foreground' [ '=' Color ] .
8458:
8459: PresRelation = '=' PresValue /
8460: '>' [ '-' ] PresMinimum /
8461: '<' [ '-' ] PresMaximum /
8462: 'IN' '[' [ '-' ] PresIntervalMin '..'
8463: [ '-' ] PresIntervalMax ']' .
8464: AdjustVal = 'Left' / 'Right' / 'VMiddle' /
8465: 'LeftWithDots' .
8466: BoolVal = 'Yes' / 'No' .
1.24 cvs 8467: StyleVal = 'Roman' / 'Italics' / 'Oblique' .
8468: WeightVal = 'Normal' / 'Bold' .
1.1 cvs 8469: FontVal = 'Times' / 'Helvetica' / 'Courier' .
8470: UnderLineVal = 'NoUnderline' / 'UnderLined' /
8471: 'OverLined' / 'CrossedOut' .
8472: ThicknessVal = 'Thick' / 'Thin' .
1.6 cvs 8473: LineStyleVal = 'Solid' / 'Dashed' / 'Dotted' .
1.1 cvs 8474: Pattern = NAME .
8475: Color = NAME .
8476: PresMinimum = NUMBER .
8477: PresMaximum = NUMBER .
8478: PresIntervalMin= NUMBER .
8479: PresIntervalMax= NUMBER .
8480: PresValue = [ '-' ] PresVal .
1.18 cvs 8481: PresVal = NUMBER .</pre>
8482: <p>
8483: The <a name="prestransl">translation rules associated with specific
8484: presentation rules</a> can use the value of the specific presentation rule
1.1 cvs 8485: that causes them to be applied. This behavior is designated by the keyword
1.18 cvs 8486: <tt>Value</tt>. For numerically-valued presentation rules, the numeric value
1.1 cvs 8487: is produced. For other presentation rules, the name of the value is
1.18 cvs 8488: produced.</p>
8489: <p>
1.1 cvs 8490: It should be noted that modifications to the layout of the document's elements
8491: that are made using the combination of the control key and a mouse button will
1.18 cvs 8492: have no effect on the translation of the document.</p>
8493: <blockquote class="example">
8494: <p>
8495: <strong>Example:</strong></p>
8496: <p>
1.3 cvs 8497: Suppose that it is desirable to use the same font sizes as in the specific
1.18 cvs 8498: presentation, but the font size must be between 10 and 18 typographer's
8499: points. If font size is set in the translated document by the string
8500: <tt>pointsize=n</tt> where <tt>n</tt> is the font size in typographer's points
8501: then the following rules will suffice:</p>
8502: <pre>PRESENTATION
1.1 cvs 8503: Size < 10 :
8504: Create 'pointsize=10';
8505: Size in [10..18] :
8506: BEGIN
8507: Create 'pointsize=';
8508: Create Value;
8509: END;
8510: Size > 18 :
1.18 cvs 8511: Create 'pointsize=18';</pre>
8512: </blockquote>
8513: </div>
1.1 cvs 8514:
1.18 cvs 8515: <div class="subsection">
1.1 cvs 8516:
1.18 cvs 8517: <h3><a name="sectc5225">Recoding of characters, symbols and graphics</a></h3>
8518: <p>
1.1 cvs 8519: The coding of characters, graphical elements and symbols as defined in Thot
8520: does not necessarily correspond to what is required by an application to which
8521: a Thot document must be exported. Because of this the translator can recode
8522: these terminal elements of the documents structure. The last sections of a
8523: translation schema are intended for this purpose, each specifying the recoding
1.18 cvs 8524: rules for one type of terminal element.</p>
8525: <p>
1.1 cvs 8526: The recoding rules for character strings are grouped by alphabets. There is a
8527: group of rules for each alphabet of the Thot document that must be translated.
1.18 cvs 8528: Each such group of rules begins with the <tt>TEXTTRANSLATE</tt> keyword,
1.1 cvs 8529: followed by the specification of the alphabet to translate and the recoding
1.18 cvs 8530: rules, between the <tt>BEGIN</tt> and <tt>END</tt> keywords unless there is
1.1 cvs 8531: only one recoding rule for the alphabet. The specification of the alphabet is
8532: not required: by default it is assumed to the Latin alphabet (the ISO Latin-1
1.18 cvs 8533: character set).</p>
8534: <p>
1.1 cvs 8535: Each recoding rule is formed by a source string between apostrophes and a
8536: target string, also between apostrophes, the two strings being separated by
1.18 cvs 8537: the arrow symbol (<tt>-></tt>), formed by the ``minus'' and ``greater than''
8538: characters. The rule is terminated by a semi-colon.</p>
8539: <pre> TextTransSeq = [ Alphabet ] TransSeq .
1.1 cvs 8540: Alphabet = NAME .
8541: TransSeq ='BEGIN' < Translation > 'END' ';' /
8542: Translation .
8543: Translation = Source [ '->' Target ] ';' .
8544: Source = STRING .
1.18 cvs 8545: Target = STRING .</pre>
8546: <p>
1.1 cvs 8547: One such rule signifies that when the source string appears in a text leaf of
8548: the document being translated, the translator must replace it, in the
8549: translated document, with the target string. The source string and the target
8550: string can have different lengths and the target string can be empty. In this
8551: last case, the translator simply suppresses every occurrence of the source
1.18 cvs 8552: string in the translated document.</p>
8553: <p>
1.1 cvs 8554: For a given alphabet, the order of the rules is not important and has no
8555: significance because the T language compiler reorders the rules in ways that
8556: speed up the translator's work. The total number of recoding rules is limited
1.18 cvs 8557: by the compiler as is the maximum length of the source and target strings.</p>
8558: <p>
1.1 cvs 8559: The recoding rules for symbols and graphical elements are written in the same
8560: manner as the recoding rules for character strings. They are preceded,
1.18 cvs 8561: respectively, by the <tt>SYMBTRANSLATE</tt> and <tt>GRAPHTRANSLATE</tt> and so
1.1 cvs 8562: not require a specification of the alphabet. Their source string is limited to
8563: one character, since, in Thot, each symbol and each graphical element is
8564: represented by a single character. The symbol and graphical element codes are
1.18 cvs 8565: defined along with the <a href="#sect7">non-standard character codes</a>.</p>
8566: <blockquote class="example">
8567: <p>
8568: <strong>Example:</strong></p>
8569: <p>
8570: In a translation schema producing documents destined for use with the
8571: L<sup>A</sup>T<sub><big>E</big></sub>X formatter, the Latin
1.1 cvs 8572: characters``é'' (octal code 351 in Thot) and ``è'' (octal code
1.18 cvs 8573: 350 in Thot) must be converted to their representation in
8574: L<sup>A</sup>T<sub><big>E</big></sub>X:</p>
8575: <pre>TEXTTRANSLATE Latin
1.1 cvs 8576: BEGIN
8577: '\350' -> '\`{e}'; { e grave }
8578: '\351' -> '\''{e}'; { e acute }
1.18 cvs 8579: END;</pre>
8580: </blockquote>
8581: </div>
8582: </div>
8583: <hr>
1.19 cvs 8584:
1.18 cvs 8585: </div>
1.1 cvs 8586:
1.18 cvs 8587: <div class="chapter">
1.1 cvs 8588:
1.18 cvs 8589: <h1><a name="sect6">Language grammars</a></h1>
8590: <p>
1.1 cvs 8591: This chapter gives the complete grammars of the languages of Thot. The
8592: grammars were presented and described in the preceding chapters, which also
8593: specify the semantics of the languages. This section gives only the
1.18 cvs 8594: syntax.</p>
1.1 cvs 8595:
1.18 cvs 8596: <div class="section">
1.1 cvs 8597:
1.18 cvs 8598: <h2><a name="sectb61">The M meta-language</a></h2>
8599: <p>
1.1 cvs 8600: The language grammars are all expressed in the same formalism, the M
1.18 cvs 8601: meta-language, which is defined in this section.</p>
8602: <pre>{ Any text between braces is a comment. }
1.1 cvs 8603: Grammar = Rule < Rule > 'END' .
8604: { The < and > signs indicate zero }
8605: { or more repetitions. }
8606: { END marks the end of the grammar. }
8607: Rule = Ident '=' RightPart '.' .
8608: { The period indicates the end of a rule }
8609: RightPart = RtTerminal / RtIntermed .
8610: { The slash indicates a choice }
8611: RtTerminal ='NAME' / 'STRING' / 'NUMBER' .
8612: { Right part of a terminal rule }
8613: RtIntermed = Possibility < '/' Possibility > .
8614: { Right part of an intermediate rule }
8615: Possibility = ElemOpt < ElemOpt > .
8616: ElemOpt = Element / '[' Element < Element > ']' /
8617: '<' Element < Element > '>' .
8618: { Brackets delimit optional parts }
8619: Element = Ident / KeyWord .
8620: Ident = NAME .
8621: { Identifier, sequence of characters
8622: KeyWord = STRING .
8623: { Character string delimited by apostrophes }
1.18 cvs 8624: END</pre>
8625: </div>
1.1 cvs 8626:
1.18 cvs 8627: <div class="section">
1.1 cvs 8628:
1.18 cvs 8629: <h2><a name="sectb62">The S language</a></h2>
8630: <p>
1.1 cvs 8631: The S language is used to write structure schemas, which contain the generic
8632: logical structures of document and object classes. It is described here in
1.18 cvs 8633: the M meta-language.</p>
8634: <pre>StructSchema = 'STRUCTURE' [ 'EXTENSION' ] ElemID ';'
1.1 cvs 8635: 'DEFPRES' PresID ';'
8636: [ 'ATTR' AttrSeq ]
8637: [ 'PARAM' RulesSeq ]
8638: [ 'STRUCT' RulesSeq ]
8639: [ 'EXTENS' ExtensRuleSeq ]
8640: [ 'ASSOC' RulesSeq ]
8641: [ 'UNITS' RulesSeq ]
8642: [ 'EXPORT' SkeletonSeq ]
8643: [ 'EXCEPT' ExceptSeq ]
8644: 'END' .
8645:
8646: ElemID = NAME .
8647: PresID = NAME .
8648:
8649: AttrSeq = Attribute < Attribute > .
8650: Attribute = AttrID '=' AttrType ';' .
8651: AttrType = 'INTEGER' / 'TEXT' /
8652: 'REFERENCE' '(' RefType ')' /
8653: ValueSeq .
8654: RefType = 'ANY' /
8655: [ FirstSec ] ElemID [ ExtStruct ] .
8656: ValueSeq = AttrVal < ',' AttrVal > .
8657: AttrID = NAME .
8658: FirstSec = 'First' / 'Second' .
8659: ExtStruct = '(' ElemID ')' .
8660: AttrVal = NAME .
8661:
8662: RulesSeq = Rule < Rule > .
8663: Rule = ElemID [ LocAttrSeq ] '='
8664: DefWithAttr ';' .
8665: LocAttrSeq = '(' 'ATTR' LocalAttr
8666: < ';' LocalAttr > ')' .
8667: LocalAttr = [ '!' ] AttrID [ '=' AttrType ] .
8668: DefWithAttr = Definition
8669: [ '+' '(' ExtensionSeq ')' ]
8670: [ '-' '(' RestrictSeq ')' ]
8671: [ 'WITH' FixedAttrSeq ] .
8672: ExtensionSeq = ExtensionElem < ',' ExtensionElem > .
8673: ExtensionElem = ElemID / 'TEXT' / 'GRAPHICS' /
8674: 'SYMBOL' / 'PICTURE' .
8675: RestrictSeq = RestrictElem < ',' RestrictElem > .
8676: RestrictElem = ElemID / 'TEXT' / 'GRAPHICS' /
8677: 'SYMBOL' / 'PICTURE' .
8678: FixedAttrSeq = FixedAttr < ',' FixedAttr > .
8679: FixedAttr = AttrID [ FixedOrModifVal ] .
8680: FixedOrModifVal= [ '?' ] '=' FixedValue .
8681: FixedValue = [ '-' ] NumValue / TextValue / AttrVal .
8682: NumValue = NUMBER .
8683: TextValue = STRING .
8684:
8685: Definition = BaseType [ LocAttrSeq ] / Constr /
8686: Element .
8687: BaseType = 'TEXT' / 'GRAPHICS' / 'SYMBOL' /
8688: 'PICTURE' / 'UNIT' / 'NATURE' .
8689: Element = ElemID [ ExtOrDef ] .
8690: ExtOrDef = 'EXTERN' / 'INCLUDED' /
8691: [ LocAttrSeq ] '=' Definition .
8692:
8693: Constr = 'LIST' [ '[' min '..' max ']' ] 'OF'
8694: '(' DefWithAttr ')' /
8695: 'BEGIN' DefOptSeq 'END' /
8696: 'AGGREGATE' DefOptSeq 'END' /
8697: 'CASE' 'OF' DefSeq 'END' /
8698: 'REFERENCE' '(' RefType ')' /
8699: 'PAIR' .
8700:
8701: min = Integer / '*' .
8702: max = Integer / '*' .
8703: Integer = NUMBER .
8704:
8705: DefOptSeq = DefOpt ';' < DefOpt ';' > .
8706: DefOpt = [ '?' ] DefWithAttr .
8707:
8708: DefSeq = DefWithAttr ';' < DefWithAttr ';' > .
8709:
8710: SkeletonSeq = SkeletonElem < ',' SkeletonElem > ';' .
8711: SkeletonElem = ElemID [ 'WITH' Contents ] .
8712: Contents = 'Nothing' / ElemID [ ExtStruct ] .
8713:
8714: ExceptSeq = Except ';' < Except ';' > .
8715: Except = [ 'EXTERN' ] [ FirstSec ] ExcTypeOrAttr ':'
8716: ExcValSeq .
8717: ExcTypeOrAttr = ElemID / AttrID .
8718: ExcValSeq = ExcValue < ',' ExcValue > .
8719: ExcValue = 'NoCut' / 'NoCreate' /
8720: 'NoHMove' / 'NoVMove' / 'NoMove' /
8721: 'NoHResize' / 'NoVResize' / 'NoResize' /
1.18 cvs 8722: 'MoveResize' /
1.1 cvs 8723: 'NewWidth' / 'NewHeight' /
8724: 'NewHPos' / 'NewVPos' /
8725: 'Invisible' / 'NoSelect' /
8726: 'Hidden' / 'ActiveRef' /
8727: 'ImportLine' / 'ImportParagraph' /
1.9 cvs 8728: 'NoPaginate' / 'ParagraphBreak' /
8729: 'HighlightChildren' / 'ExtendedSelection' /
8730: 'ReturnCreateNL' .
1.1 cvs 8731:
8732: ExtensRuleSeq = ExtensRule ';' < ExtensRule ';' > .
8733: ExtensRule = RootOrElem [ LocAttrSeq ]
8734: [ '+' '(' ExtensionSeq ')' ]
8735: [ '-' '(' RestrictSeq ')' ]
8736: [ 'WITH' FixedAttrSeq ] .
8737: RootOrElem = 'Root' / ElemID .
8738:
1.18 cvs 8739: END</pre>
8740: </div>
1.1 cvs 8741:
1.18 cvs 8742: <div class="section">
1.1 cvs 8743:
1.18 cvs 8744: <h2><a name="sectb63">The P language</a></h2>
8745: <p>
1.1 cvs 8746: The P language is used to write presentation schemas, which define the
8747: graphical presentation rules to be applied to different classes of documents
1.18 cvs 8748: and objects. It is described here in the M meta-language.</p>
8749: <pre>PresSchema = 'PRESENTATION' ElemID ';'
1.1 cvs 8750: [ 'VIEWS' ViewSeq ]
8751: [ 'PRINT' PrintViewSeq ]
8752: [ 'COUNTERS' CounterSeq ]
8753: [ 'CONST' ConstSeq ]
8754: [ 'VAR' VarSeq ]
8755: [ 'DEFAULT' ViewRuleSeq ]
8756: [ 'BOXES' BoxSeq ]
8757: [ 'RULES' PresentSeq ]
8758: [ 'ATTRIBUTES' PresAttrSeq ]
8759: [ 'TRANSMIT' TransmitSeq ]
8760: 'END' .
8761:
8762: ElemID = NAME .
8763:
8764: ViewSeq = ViewDeclaration
8765: < ',' ViewDeclaration > ';' .
8766: ViewDeclaration = ViewID [ 'EXPORT' ] .
8767: ViewID = NAME .
8768:
8769: PrintViewSeq = PrintView < ',' PrintView > ';' .
8770: PrintView = ViewID / ElemID .
8771:
8772: CounterSeq = Counter < Counter > .
8773: Counter = CounterID ':' CounterFunc ';' .
8774: CounterID = NAME .
8775: CounterFunc = 'RANK' 'OF' TypeOrPage [ SLevelAsc ]
8776: [ 'INIT' AttrID ] [ 'REINIT' AttrID ] /
8777: SetFunction < SetFunction >
8778: AddFunction < AddFunction >
8779: [ 'INIT' AttrID ] /
1.16 cvs 8780: 'RLEVEL' 'OF' ElemID .
1.1 cvs 8781: SLevelAsc = [ '-' ] LevelAsc .
8782: LevelAsc = NUMBER .
8783: SetFunction = 'SET' CounterValue 'ON' TypeOrPage .
8784: AddFunction = 'ADD' CounterValue 'ON' TypeOrPage .
8785: TypeOrPage = 'Page' [ '(' ViewID ')' ] /
1.16 cvs 8786: [ '*' ] ElemID .
1.1 cvs 8787: CounterValue = NUMBER .
8788:
8789: ConstSeq = Const < Const > .
8790: Const = ConstID '=' ConstType ConstValue ';' .
8791: ConstID = NAME .
8792: ConstType = 'Text' [ Alphabet ] / 'Symbol' /
8793: 'Graphics' / 'Picture' .
8794: ConstValue = STRING .
8795: Alphabet = NAME .
8796:
8797: VarSeq = Variable < Variable > .
8798: Variable = VarID ':' FunctionSeq ';' .
8799: VarID = NAME .
8800: FunctionSeq = Function < Function > .
8801: Function = 'DATE' / 'FDATE' /
8802: 'DocName' / 'DirName' /
8803: 'ElemName' / 'AttributeName' /
8804: ConstID / ConstType ConstValue /
8805: AttrID /
8806: 'VALUE' '(' PageAttrCtr ','
8807: CounterStyle ')' .
8808: PageAttrCtr = 'PageNumber' [ '(' ViewID ')' ] /
8809: [ MinMax ] CounterID / AttrID .
8810: CounterStyle = 'Arabic' / 'LRoman' / 'URoman' /
8811: 'Uppercase' / 'Lowercase' .
8812: MinMax = 'MaxRangeVal' / 'MinRangeVal' .
8813:
8814: BoxSeq = Box < Box > .
8815: Box = 'FORWARD' BoxID ';' /
8816: BoxID ':' ViewRuleSeq .
8817: BoxID = NAME .
8818:
8819: PresentSeq = Present < Present > .
8820: Present = [ '*' ] [ FirstSec ] ElemID ':'
8821: ViewRuleSeq .
8822: FirstSec = 'First' / 'Second' .
8823:
8824: PresAttrSeq = PresAttr < PresAttr > .
8825: PresAttr = AttrID [ '(' [ FirstSec ] ElemID ')' ]
8826: [ AttrRelation ] ':' ViewRuleSeq .
8827: AttrID = NAME .
8828: AttrRelation = '=' AttrVal /
8829: '>' [ '-' ] MinValue /
8830: '<' [ '-' ] MaxValue /
8831: 'IN' '[' [ '-' ] LowerBound '..'
8832: [ '-' ] UpperBound ']' /
8833: 'GREATER' AttrID /
8834: 'EQUAL' AttrID /
8835: 'LESS' AttrID .
8836: AttrVal = [ '-' ] EqualNum / EqualText / AttrValue .
8837: MinValue = NUMBER .
8838: MaxValue = NUMBER .
8839: LowerBound = NUMBER .
8840: UpperBound = NUMBER.
8841: EqualNum = NUMBER .
8842: EqualText = STRING .
8843: AttrValue = NAME .
8844:
8845: ViewRuleSeq = 'BEGIN' < RulesAndCond > < ViewRules >
8846: 'END' ';' /
8847: ViewRules / CondRules / Rule .
8848: RulesAndCond = CondRules / Rule .
8849: ViewRules = 'IN' ViewID CondRuleSeq .
8850: CondRuleSeq = 'BEGIN' < RulesAndCond > 'END' ';' /
8851: CondRules / Rule .
8852: CondRules = CondRule < CondRule >
8853: [ 'Otherwise' RuleSeq ] .
8854: CondRule = 'IF' ConditionSeq RuleSeq .
8855: RulesSeq = 'BEGIN' Rule < Rule > 'END' ';' / Rule .
8856:
1.6 cvs 8857: ConditionSeq = Condition < 'AND' Condition > .
8858: Condition = [ 'NOT' ] [ 'Target' ] ConditionElem .
8859: ConditionElem = 'First' / 'Last' /
8860: [ 'Immediately' ] 'Within' [ NumParent ]
8861: ElemID [ ExtStruct ] /
8862: ElemID /
8863: 'Referred' / 'FirstRef' / 'LastRef' /
8864: 'ExternalRef' / 'InternalRef' / 'CopyRef' /
8865: 'AnyAttributes' / 'FirstAttr' / 'LastAttr' /
8866: 'UserPage' / 'StartPage' / 'ComputedPage' /
8867: 'Empty' /
8868: '(' [ MinMax ] CounterName CounterCond ')' /
8869: CondPage '(' CounterID ')' .
8870: NumParent = [ GreaterLess ] NParent .
8871: GreaterLess = '>' / '<' .
8872: NParent = NUMBER.
8873: CounterCond = '<' MaxCtrVal / '>' MinCtrVal /
8874: '=' EqCtrVal /
8875: 'IN' '[' ['-'] MinCtrBound '..'
8876: ['-'] MaxCtrBound ']' .
8877: PageCond = 'Even' / 'Odd' / 'One' .
8878: MaxCtrVal = NUMBER .
8879: MinCtrVal = NUMBER .
8880: EqCtrVal = NUMBER .
8881: MaxCtrBound = NUMBER .
8882: MinCtrBound = NUMBER .
1.1 cvs 8883:
8884: Rule = PresParam ';' / PresFunc ';' .
8885: PresParam = 'VertRef' ':' HorizPosition /
8886: 'HorizRef' ':' VertPosition /
8887: 'VertPos' ':' VPos /
8888: 'HorizPos' ':' HPos /
8889: 'Height' ':' Extent /
8890: 'Width' ':' Extent /
8891: 'VertOverflow' ':' Boolean /
8892: 'HorizOverflow' ':' Boolean /
1.26 cvs 8893: 'MarginTop' ':' MarginWidth /
8894: 'MarginRight' ':' MarginWidth /
8895: 'MarginBottom' ':' MarginWidth /
8896: 'MarginLeft' ':' MarginWidth /
8897: 'PaddingTop' ':' PaddingWidth /
8898: 'PaddingRight' ':' PaddingWidth /
8899: 'PaddingBottom' ':' PaddingWidth /
8900: 'PaddingLeft' ':' PaddingWidth /
8901: 'BorderTopWidth' ':' BorderWidth /
8902: 'BorderRightWidth' ':' BorderWidth /
8903: 'BorderBottomWidth' ':' BorderWidth /
8904: 'BorderLeftWidth' ':' BorderWidth /
8905: 'BorderTopColor' ':' BorderColor /
8906: 'BorderRightColor' ':' BorderColor /
8907: 'BorderBottomColor' ':' BorderColor /
8908: 'BorderLeftColor' ':' BorderColor /
8909: 'BorderTopStyle' ':' BorderStyle /
8910: 'BorderRightStyle' ':' BorderStyle /
8911: 'BorderBottomStyle' ':' BorderStyle /
8912: 'BorderLeftStyle' ':' BorderStyle .
1.1 cvs 8913: 'LineSpacing' ':' DistOrInherit /
8914: 'Indent' ':' DistOrInherit /
8915: 'Adjust' ':' AlignOrInherit /
8916: 'Justify' ':' BoolInherit /
8917: 'Hyphenate' ':' BoolInherit /
8918: 'PageBreak' ':' Boolean /
8919: 'LineBreak' ':' Boolean /
8920: 'InLine' ':' Boolean /
8921: 'NoBreak1' ':' AbsDist /
8922: 'NoBreak2' ':' AbsDist /
8923: 'Gather' ':' Boolean /
8924: 'Visibility' ':' NumberInherit /
8925: 'Size' ':' SizeInherit /
8926: 'Font' ':' NameInherit /
8927: 'Style' ':' StyleInherit /
1.23 cvs 8928: 'Weight' ':' WeightInherit /
1.1 cvs 8929: 'Underline' ':' UnderLineInherit /
8930: 'Thickness' ':' ThicknessInherit /
8931: 'Depth' ':' NumberInherit /
8932: 'LineStyle' ':' LineStyleInherit /
8933: 'LineWeight' ':' DistOrInherit /
8934: 'FillPattern' ':' NameInherit /
8935: 'Background' ':' NameInherit /
1.13 cvs 8936: 'Foreground' ':' NameInherit /
1.1 cvs 8937: 'Content' ':' VarConst .
8938: PresFunc = Creation '(' BoxID ')' /
8939: 'Line' /
8940: 'NoLine' /
8941: 'Page' '(' BoxID ')' /
1.13 cvs 8942: 'Copy' '(' BoxTypeToCopy ')' /
8943: 'ShowBox' /
1.18 cvs 8944: 'BackgroundPicture' ':' FileName /
8945: 'PictureMode' ':' PictMode .
1.1 cvs 8946:
8947: BoxTypeToCopy = BoxID [ ExtStruct ] /
8948: ElemID [ ExtStruct ] .
8949: ExtStruct = '(' ElemID ')' .
8950:
8951: Distance = [ Sign ] AbsDist .
8952: Sign = '+' / '-' .
8953: AbsDist = IntegerOrAttr [ '.' DecimalPart ]
8954: [ Unit ] .
8955: IntegerOrAttr = IntegerPart / AttrID .
8956: IntegerPart = NUMBER .
8957: DecimalPart = NUMBER .
8958: Unit = 'em' / 'ex' / 'cm' / 'mm' / 'in' / 'pt' /
8959: 'pc' / 'px' / '%' .
8960:
8961: HPos = 'nil' / VertAxis '=' HorizPosition
8962: [ 'UserSpecified' ] .
8963: VPos = 'nil' / HorizAxis '=' VertPosition
8964: [ 'UserSpecified' ] .
8965: VertAxis = 'Left' / 'VMiddle' / 'VRef' / 'Right' .
8966: HorizAxis = 'Top' / 'HMiddle' / 'HRef' / 'Bottom' .
8967:
1.6 cvs 8968: VertPosition = Reference '.' HorizAxis [ Distance ] .
8969: HorizPosition = Reference '.' VertAxis [ Distance ] .
8970: Reference = 'Enclosing' [ BoxTypeNot ] /
8971: 'Enclosed' [ BoxTypeNot ] /
8972: 'Previous' [ BoxTypeNot ] /
8973: 'Next' [ BoxTypeNot ] /
8974: 'Referred' [ BoxTypeNot ] /
8975: 'Creator' /
8976: 'Root' /
8977: '*' /
8978: BoxOrType .
8979: BoxOrType = BoxID /
8980: [ '*' ] [ FirstSec ] ElemID /
1.17 cvs 8981: 'AnyElem' / 'AnyBox' /
8982: 'ElemWithAttr' AttrID .
1.6 cvs 8983: BoxTypeNot = [ 'NOT' ] BoxOrType .
8984:
8985: Extent = Reference '.' HeightWidth
8986: [ Relation ] [ 'Min' ] /
8987: AbsDist [ 'UserSpecified' ] [ 'Min' ] /
8988: HPos / VPos .
8989: HeightWidth = 'Height' / 'Width' .
8990: Relation = '*' ExtentAttr '%' / Distance .
8991: ExtentAttr = ExtentVal / AttrID .
8992: ExtentVal = NUMBER .
1.26 cvs 8993:
8994: MarginWidth = InheritParent / 'Auto' / Distance .
8995: PaddingWidth = InheritParent / Distance .
8996: BorderWidth = InheritParent / 'Thin' / 'Medium' / 'Thick' / Distance .
8997: BorderColor = InheritParent / 'Transparent' / 'Foreground' /
8998: ColorName .
8999: BorderStyle = InheritParent /
9000: 'None' / 'Hidden' / 'Dotted' / 'Dashed' / 'Solid' /
9001: 'Double' / 'Groove' / 'Ridge' / 'Inset' / 'Outset' .
1.27 cvs 9002: InheritParent = 'Enclosing' '=' / 'Creator' '=' .
1.26 cvs 9003: ColorName = NAME .
1.6 cvs 9004:
9005: Inheritance = Kinship InheritedValue .
9006: Kinship = 'Enclosing' / 'GrandFather'/ 'Enclosed' /
9007: 'Previous' / 'Creator' .
9008: InheritedValue = '+' PosIntAttr [ 'Max' maximumA ] /
9009: '-' NegIntAttr [ 'Min' minimumA ] /
9010: '=' .
9011: PosIntAttr = PosInt / AttrID .
9012: PosInt = NUMBER .
9013: NegIntAttr = NegInt / AttrID .
9014: NegInt = NUMBER .
9015: maximumA = maximum / AttrID .
9016: maximum = NUMBER .
9017: minimumA = minimum / AttrID .
9018: minimum = NUMBER .
9019:
9020: AlignOrInherit = Kinship '=' / Alignment .
9021: Alignment = 'Left' / 'Right' / 'VMiddle' /
9022: 'LeftWithDots' .
1.1 cvs 9023:
1.6 cvs 9024: DistOrInherit = Kinship InheritedDist / Distance .
9025: InheritedDist = '=' / '+' AbsDist / '-' AbsDist .
1.1 cvs 9026:
1.6 cvs 9027: BoolInherit = Boolean / Kinship '=' .
9028: Boolean = 'Yes' / 'No' .
1.1 cvs 9029:
1.6 cvs 9030: NumberInherit = Integer / AttrID / Inheritance .
9031: Integer = NUMBER .
1.1 cvs 9032:
9033: LineStyleInherit= Kinship '=' / 'Solid' / 'Dashed' /
9034: 'Dotted' .
9035:
1.6 cvs 9036: SizeInherit = SizeAttr [ 'pt' ] / Kinship InheritedSize .
9037: InheritedSize = '+' SizeAttr [ 'pt' ]
9038: [ 'Max' MaxSizeAttr ] /
9039: '-' SizeAttr [ 'pt' ]
9040: [ 'Min' MinSizeAttr ] /
1.22 cvs 9041: '*' PercentSizeAttr '%' /
1.6 cvs 9042: '=' .
9043: SizeAttr = Size / AttrID .
9044: Size = NUMBER .
9045: MaxSizeAttr = MaxSize / AttrID .
9046: MaxSize = NUMBER .
9047: MinSizeAttr = MinSize / AttrID .
9048: MinSize = NUMBER .
1.22 cvs 9049: PercentSizeAttr = PercentSize / AttrID .
9050: PercentSize = NUMBER .
1.6 cvs 9051:
9052: NameInherit = Kinship '=' / FontName .
9053: FontName = NAME .
9054: StyleInherit = Kinship '=' /
1.23 cvs 9055: 'Roman' / 'Italics' / 'Oblique' .
9056: WeightInherit = Kinship '=' /
9057: 'Normal' / 'Bold' .
1.1 cvs 9058: UnderLineInherit= Kinship '=' /
1.6 cvs 9059: 'NoUnderline' / 'Underlined' /
9060: 'Overlined' / 'CrossedOut' .
1.1 cvs 9061: ThicknessInherit= Kinship '=' / 'Thick' / 'Thin' .
1.13 cvs 9062:
9063: FileName = STRING .
9064: PictMode = 'NormalSize' / 'Scale' /
9065: 'RepeatXY' / 'RepeatX' / 'RepeatY' .
1.1 cvs 9066:
1.6 cvs 9067: VarConst = ConstID / ConstType ConstValue /
9068: VarID / '(' FunctionSeq ')' /
9069: ElemID .
9070:
9071: Creation = Create [ 'Repeated' ] .
9072: Create = 'CreateFirst' / 'CreateLast' /
9073: 'CreateBefore' / 'CreateAfter' /
9074: 'CreateEnclosing' .
9075:
9076: TransmitSeq = Transmit < Transmit > .
9077: Transmit = TypeOrCounter 'To' ExternAttr
9078: '(' ElemID ')' ';' .
9079: TypeOrCounter = CounterID / ElemID .
9080: ExternAttr = NAME .
1.1 cvs 9081:
1.18 cvs 9082: END</pre>
9083: </div>
1.1 cvs 9084:
1.18 cvs 9085: <div class="section">
1.1 cvs 9086:
1.18 cvs 9087: <h2><a name="sectb64">The T language</a></h2>
9088: <pre>TransSchema = 'TRANSLATION' ElemID ';'
1.1 cvs 9089: [ 'LINELENGTH' LineLength ';' ]
9090: [ 'LINEEND' CHARACTER ';' ]
9091: [ 'LINEENDINSERT' STRING ';' ]
9092: [ 'BUFFERS' BufferSeq ]
9093: [ 'COUNTERS' CounterSeq ]
9094: [ 'CONST' ConstSeq ]
9095: [ 'VAR' VariableSeq ]
9096: 'RULES' ElemSeq
9097: [ 'ATTRIBUTES' AttrSeq ]
9098: [ 'PRESENTATION' PresSeq ]
9099: < 'TEXTTRANSLATE' TextTransSeq >
9100: [ 'SYMBTRANSLATE' TransSeq ]
9101: [ 'GRAPHTRANSLATE' TransSeq ]
9102: 'END' .
9103:
9104: LineLength = NUMBER .
9105:
9106: BufferSeq = Buffer < Buffer > .
9107: Buffer = BufferID [ '(' 'Picture' ')' ] ';' .
9108: BufferID = NAME .
9109:
9110: CounterSeq = Counter < Counter > .
9111: Counter = CounterID [ ':' CounterFunc ] ';' .
9112: CounterID = NAME .
9113: CounterFunc = 'Rank' 'of' ElemID [ SLevelAsc ]
9114: [ 'Init' AttrID ] /
9115: 'Rlevel' 'of' ElemID /
9116: 'Set' InitValue 'On' ElemID
9117: 'Add' Increment 'On' ElemID
9118: [ 'Init' AttrID ] .
9119: SLevelAsc = [ '-' ] LevelAsc .
9120: LevelAsc = NUMBER .
9121: InitValue = NUMBER .
9122: Increment = NUMBER .
9123: ElemID = NAME .
9124: AttrID = NAME .
9125:
9126: ConstSeq = Const < Const > .
9127: Const = ConstID '=' ConstValue ';' .
9128: ConstID = NAME .
9129: ConstValue = STRING .
9130:
9131: VariableSeq = Variable < Variable > .
9132: Variable = VarID ':' Function < Function > ';' .
9133: VarID = NAME .
9134: Function = 'Value' '(' CounterID [ ':' Length ]
9135: [ ',' CounterStyle ] ')' /
9136: 'FileDir' / 'FileName' / 'Extension' /
9137: 'DocumentName' / 'DocumentDir' /
9138: ConstID / CharString /
9139: BufferID / AttrID .
9140: Length = NUMBER .
9141: CounterStyle= 'Arabic' / 'LRoman' / 'URoman' /
9142: 'Uppercase' / 'Lowercase' .
9143: CharString = STRING .
9144:
9145: ElemSeq = TransType < TransType > .
9146: TransType = [ FirstSec ] ElemID ':' RuleSeq .
9147: FirstSec = 'First' / 'Second' .
9148: RuleSeq = Rule / 'BEGIN' < Rule > 'END' ';' .
9149: Rule = SimpleRule / ConditionBlock .
9150: ConditionBlock= 'IF' ConditionSeq SimpleRuleSeq .
9151: SimpleRuleSeq = 'BEGIN' < SimpleRule > 'END' ';' /
9152: SimpleRule .
9153:
9154: ConditionSeq = Condition [ 'AND' Condition ] .
9155: Condition = [ 'NOT' ] [ 'Target' ] Cond .
9156: Cond = CondElem / CondAscend .
9157: CondElem = 'FirstRef' / 'LastRef' /
9158: 'ExternalRef' /
9159: 'Defined' /
9160: 'Alphabet' '=' Alphabet /
9161: 'ComputedPage' / 'StartPage' /
9162: 'UserPage' / 'ReminderPage' /
9163: 'Empty' /
1.18 cvs 9164: ElemID /
1.1 cvs 9165: 'FirstAttr' / 'LastAttr' .
9166: CondAscend = [ Ascend ] CondOnAscend .
9167: Ascend = '*' / 'Parent' / 'Ancestor' LevelOrType .
9168: LevelOrType = CondRelLevel / ElemID [ ExtStruct ] .
9169: CondRelLevel = NUMBER .
9170: CondOnAscend = 'First' / 'Last' /
9171: 'Referred' /
9172: [ 'Immediately' ] 'Within' [ NumParent ]
9173: ElemID [ ExtStruct ] /
9174: 'Attributes' /
9175: AttrID [ RelatAttr ] /
9176: 'Presentation' /
9177: PresRule /
9178: 'Comment' .
9179: NumParent = [ GreaterLess ] NParent .
9180: GreaterLess = '>' / '<' .
9181: NParent = NUMBER.
9182: Alphabet = NAME .
9183: RelatAttr = '=' Value /
9184: '>' [ '-' ] Minimum /
9185: '<' [ '-' ] Maximum /
9186: 'IN' '[' [ '-' ] MinInterval '..'
9187: [ '-' ] MaxInterval ']' .
9188: Value = [ '-' ] IntegerVal / TextVal / AttrValue .
9189: Minimum = NUMBER .
9190: Maximum = NUMBER .
9191: MinInterval = NUMBER .
9192: MaxInterval = NUMBER .
9193: IntegerVal = NUMBER .
9194: TextVal = STRING .
9195: AttrValue = NAME .
9196:
9197: SimpleRule = 'Create' [ 'IN' VarID ] Object
9198: [ Position ] ';' /
9199: 'Write' Object [ Position ] ';' /
9200: 'Read' BufferID [ Position ] ';' /
9201: 'Include' File [ Position ] ';' /
1.6 cvs 9202: 'Get' [ RelPosition ] ElemID
9203: [ ExtStruct ]
9204: [ Position ] ';' /
1.1 cvs 9205: 'Copy' [ RelPosition ] ElemID
9206: [ ExtStruct ]
9207: [ Position ] ';' /
9208: 'Use' TrSchema [ 'For' ElemID ] ';' /
9209: 'Remove' ';' /
9210: 'NoTranslation' ';' /
9211: 'NoLineBreak' ';' /
9212: 'ChangeMainFile' VarID [ Position ] ';' /
1.14 cvs 9213: 'RemoveFile' VarID [ Position ] ';' /
1.10 cvs 9214: 'Set' CounterID InitValue [ Position ] ';' /
9215: 'Add' CounterID Increment [ Position ] ';' /
1.25 cvs 9216: 'Indent' [ 'IN' VarID ] Indent [ Position ] ';' .
1.10 cvs 9217:
1.25 cvs 9218: Indent = 'Suspend' / 'Resume' / [ IndentSign ] IndentValue .
1.10 cvs 9219: IndentSign = '+' / '-' .
9220: IndentValue = NUMBER .
1.1 cvs 9221:
9222: Object = ConstID / CharString /
9223: BufferID /
9224: VarID /
9225: '(' Function < Function > ')' /
1.21 cvs 9226: [ 'Translated' ] AttrID /
1.1 cvs 9227: 'Value' /
9228: 'Content' /
9229: 'Comment' /
9230: 'Attributes' /
9231: 'Presentation' /
9232: 'RefId' /
9233: 'PairId' /
9234: 'FileDir' / 'FileName' / 'Extension' /
9235: 'DocumentName' / 'DocumentDir' /
9236: [ 'Referred' ] ReferredObject .
9237: Position = 'After' / 'Before' .
9238:
1.6 cvs 9239: ReferredObject= VarID /
9240: ElemID [ ExtStruct ] /
9241: 'RefId' /
9242: 'DocumentName' / 'DocumentDir' .
1.1 cvs 9243:
1.6 cvs 9244: File = FileName / BufferID .
9245: FileName = STRING .
1.1 cvs 9246:
1.6 cvs 9247: RelPosition = 'Included' / 'Referred' .
9248: ExtStruct = '(' ElemID ')' .
1.1 cvs 9249:
1.6 cvs 9250: TrSchema = NAME .
9251:
9252: AttrSeq = TransAttr < TransAttr > .
9253: TransAttr = AttrID [ '(' ElemID ')' ]
9254: [ RelatAttr ] ':' RuleSeq .
9255:
9256: PresSeq = PresTrans < PresTrans > .
9257: PresTrans = PresRule ':' RuleSeq .
9258: PresRule = 'Size' [ PresRelation ] /
9259: 'Indent' [ PresRelation ] /
9260: 'LineSpacing' [ PresRelation ] /
9261: 'Adjust' [ '=' AdjustVal ] /
9262: 'Justify' [ '=' BoolVal ] /
9263: 'Hyphenate' [ '=' BoolVal ] /
9264: 'Style' [ '=' StyleVal ] /
1.24 cvs 9265: 'Weight' [ '=' WeightVal ] /
1.6 cvs 9266: 'Font' [ '=' FontVal ] /
9267: 'UnderLine' [ '=' UnderLineVal ] /
9268: 'Thickness' [ '=' ThicknessVal ] /
9269: 'LineStyle' [ '=' LineStyleVal ] /
9270: 'LineWeight' [ PresRelation ] /
9271: 'FillPattern' [ '=' Pattern ] /
9272: 'Background' [ '=' Color ] /
9273: 'Foreground' [ '=' Color ] .
9274:
9275: PresRelation = '=' PresValue /
9276: '>' [ '-' ] PresMinimum /
9277: '<' [ '-' ] PresMaximum /
9278: 'IN' '[' [ '-' ] PresIntervalMin '..'
9279: [ '-' ] PresIntervalMax ']' .
9280: AdjustVal = 'Left' / 'Right' / 'VMiddle' /
9281: 'LeftWithDots' .
9282: BoolVal = 'Yes' / 'No' .
1.24 cvs 9283: StyleVal = 'Roman' / 'Italics' / 'Oblique' .
9284: WeightVal = 'Normal' / 'Bold' .
1.6 cvs 9285: FontVal = 'Times' / 'Helvetica' / 'Courier' .
9286: UnderLineVal = 'NoUnderline' / 'UnderLined' /
9287: 'OverLined' / 'CrossedOut' .
9288: ThicknessVal = 'Thick' / 'Thin' .
9289: LineStyleVal = 'Solid' / 'Dashed' / 'Dotted' .
9290: Pattern = NAME .
9291: Color = NAME .
9292: PresMinimum = NUMBER .
9293: PresMaximum = NUMBER .
1.1 cvs 9294: PresIntervalMin= NUMBER .
9295: PresIntervalMax= NUMBER .
1.6 cvs 9296: PresValue = [ '-' ] PresVal .
9297: PresVal = NUMBER .
1.1 cvs 9298:
1.6 cvs 9299: TextTransSeq = [ Alphabet ] TransSeq .
9300: Alphabet = NAME .
9301: TransSeq = 'BEGIN' < Translation > 'END' ';' /
9302: Translation .
9303: Translation = Source [ '->' Target ] ';' .
9304: Source = STRING .
1.18 cvs 9305: Target = STRING .</pre>
9306: </div>
9307: <hr>
1.19 cvs 9308:
1.18 cvs 9309: </div>
1.1 cvs 9310:
1.18 cvs 9311: <div class="chapter">
1.1 cvs 9312:
1.18 cvs 9313: <h1><a name="sect7">Character coding</a></h1>
1.1 cvs 9314:
1.18 cvs 9315: <div class="section">
1.1 cvs 9316:
1.18 cvs 9317: <h2><a name="sectb71">Characters</a></h2>
9318: <p>
1.1 cvs 9319: The characters of the Latin alphabet follow the encoding defined in the ISO
1.5 cvs 9320: 8859-1 (ISO Latin-1) standard. The characters of the Greek alphabet follow
1.18 cvs 9321: the encoding defined by Adobe for its Symbol font (Adobe FontSpecific).</p>
9322: <p>
1.1 cvs 9323: Characters whose octal code is greater than 0200 are written in the form of
9324: their octal code preceded by a backslash character (``\''). For example, the
1.18 cvs 9325: French word 'Résumé' is written <tt>R\351sum\351</tt>.</p>
9326: <p>
1.2 cvs 9327: To the ISO 8859-1 encoding four characters with the following codes have been
1.18 cvs 9328: added:<br>
9329: <tt>212</tt>: line break<br>
9330: <tt>240</tt>: sticky space<br>
9331: <tt>201</tt>: thin space<br>
9332: <tt>202</tt>: en space</p>
9333: <p>
9334: The <tt>212</tt> character is a ``line break'' character which forces a line
9335: break. The <tt>240</tt> character is a ``sticky space'', which cannot be
9336: replaced by a line break.</p>
9337: </div>
1.1 cvs 9338:
1.18 cvs 9339: <div class="section">
1.1 cvs 9340:
1.18 cvs 9341: <h2><a name="sectb72">Symbols</a></h2>
9342: <p>
1.1 cvs 9343: The table below gives the codes for the symbols of Thot. Symbols can be used
9344: in presentation schemas constants and in transcoding rules of translation
1.18 cvs 9345: schemas. Each symbol is represented by a single character.</p>
9346: <ul>
9347: <li>
9348: <tt>r</tt>: a radical
1.19 cvs 9349: </li>
1.18 cvs 9350: <li>
9351: <tt>i</tt>: a simple integral
1.19 cvs 9352: </li>
1.18 cvs 9353: <li>
9354: <tt>c</tt>: a curvilinear integral
1.19 cvs 9355: </li>
1.18 cvs 9356: <li>
9357: <tt>d</tt>: a double integral
1.19 cvs 9358: </li>
1.18 cvs 9359: <li>
9360: <tt>t</tt>: a triple integral
1.19 cvs 9361: </li>
1.18 cvs 9362: <li>
9363: <tt>S</tt>: the summation symbol
1.19 cvs 9364: </li>
1.18 cvs 9365: <li>
9366: <tt>P</tt>: the product symbol
1.19 cvs 9367: </li>
1.18 cvs 9368: <li>
9369: <tt>U</tt>: the union symbol
1.19 cvs 9370: </li>
1.18 cvs 9371: <li>
9372: <tt>I</tt>: the intersection symbol
1.19 cvs 9373: </li>
1.18 cvs 9374: <li>
9375: <tt>></tt>: a right arrow
1.19 cvs 9376: </li>
1.18 cvs 9377: <li>
9378: <tt><</tt>: a left arrow
1.19 cvs 9379: </li>
1.18 cvs 9380: <li>
9381: <tt>^</tt>: an up arrow
1.19 cvs 9382: </li>
1.18 cvs 9383: <li>
9384: <tt>V</tt>: a down arrow
1.19 cvs 9385: </li>
1.18 cvs 9386: <li>
9387: <tt>(</tt>: an opening parenthesis
1.19 cvs 9388: </li>
1.18 cvs 9389: <li>
9390: <tt>)</tt>: a closing parenthesis
1.19 cvs 9391: </li>
1.18 cvs 9392: <li>
9393: <tt>{</tt>: an opening brace
1.19 cvs 9394: </li>
1.18 cvs 9395: <li>
9396: <tt>}</tt>: a closing brace
1.19 cvs 9397: </li>
1.18 cvs 9398: <li>
9399: <tt>[</tt>: an opening bracket
1.19 cvs 9400: </li>
1.18 cvs 9401: <li>
9402: <tt>]</tt>: a closing bracket
1.19 cvs 9403: </li>
1.18 cvs 9404: </ul>
9405: </div>
1.1 cvs 9406:
1.18 cvs 9407: <div class="section">
1.1 cvs 9408:
1.18 cvs 9409: <h2><a name="sectb73">Graphical elements</a></h2>
9410: <p>
1.1 cvs 9411: The table below gives the codes for the graphical elements of Thot. These
9412: elements can be used in presentation schemas constants and in transcoding
9413: rules of translation schemas. Each graphical element is represented by a
1.18 cvs 9414: single character.</p>
9415: <ul>
9416: <li>
9417: a: a circle
1.19 cvs 9418: </li>
1.18 cvs 9419: <li><p>
9420: <tt>A</tt>: an open curve with an arrow head at the end</p>
1.19 cvs 9421: </li>
1.18 cvs 9422: <li>
9423: <tt>b</tt>: a horizontal line along the lower side of the box
1.19 cvs 9424: </li>
1.18 cvs 9425: <li>
9426: <tt>B</tt>: an open curve
1.19 cvs 9427: </li>
1.18 cvs 9428: <li>
9429: <tt>c</tt>: an ellipse inscribed in the box
1.19 cvs 9430: </li>
1.18 cvs 9431: <li>
9432: <tt>C</tt>: a rectangle with rounded corners
1.19 cvs 9433: </li>
1.18 cvs 9434: <li>
9435: <tt>D</tt>: an open curve with two arrow heads
1.19 cvs 9436: </li>
1.18 cvs 9437: <li>
9438: <tt>e</tt>: The northwest/southeast diagonal of the box with an arrowhead at
9439: the bottom
1.19 cvs 9440: </li>
1.18 cvs 9441: <li>
9442: <tt>E</tt>: The southwest/northeast diagonal of the box with an arrowhead at
9443: the top
1.19 cvs 9444: </li>
1.18 cvs 9445: <li>
9446: <tt>F</tt>: an open curve with an arrow head at start
1.28 ! cvs 9447: </li>
! 9448: <li>
! 9449: <tt>g</tt>: a line from the origin of the box to its opposite corner
1.19 cvs 9450: </li>
1.18 cvs 9451: <li>
9452: <tt>h</tt>: a horizontal line as wide as the box and placed in its middle
1.19 cvs 9453: </li>
1.18 cvs 9454: <li>
9455: <tt>l</tt>: a vertical line on the left side of the box
1.19 cvs 9456: </li>
1.18 cvs 9457: <li>
9458: <tt>L</tt>: a lozenge
1.19 cvs 9459: </li>
1.18 cvs 9460: <li>
9461: <tt>M</tt>: an open broken line with two arrow heads
1.19 cvs 9462: </li>
1.18 cvs 9463: <li>
9464: <tt>N</tt>: an open broken line with an arrow head at start
1.19 cvs 9465: </li>
1.18 cvs 9466: <li>
9467: <tt>o</tt>: The southwest/northeast diagonal of the box with an arrowhead at
9468: the bottom
1.19 cvs 9469: </li>
1.18 cvs 9470: <li>
9471: <tt>O</tt>: The northwest/southeast diagonal of the box with an arrowhead at
9472: the top
1.19 cvs 9473: </li>
1.18 cvs 9474: <li>
9475: <tt>p</tt>: a polygon
1.19 cvs 9476: </li>
1.18 cvs 9477: <li>
9478: <tt>P</tt>: a rectangle with round corners and a horizontal bar at the top
1.19 cvs 9479: </li>
1.18 cvs 9480: <li>
9481: <tt>Q</tt>: an ellipse with a horizontal bar at the top
1.19 cvs 9482: </li>
1.18 cvs 9483: <li>
9484: <tt>r</tt>: a vertical line on the right side of the box
1.19 cvs 9485: </li>
1.18 cvs 9486: <li>
9487: <tt>R</tt>: a rectangle which is the shape of the box
1.19 cvs 9488: </li>
1.18 cvs 9489: <li>
9490: <tt>s</tt>: a closed curve
1.19 cvs 9491: </li>
1.18 cvs 9492: <li>
9493: <tt>S</tt>: an open broken line
1.19 cvs 9494: </li>
1.18 cvs 9495: <li>
9496: <tt>t</tt>: a horizontal line along the upper side of the box
1.19 cvs 9497: </li>
1.18 cvs 9498: <li>
9499: <tt>U</tt>: an open broken line with an arrow head at the end
1.19 cvs 9500: </li>
1.18 cvs 9501: <li>
9502: <tt>v</tt>: a vertical line as tall as the box and placed in its middle
1.19 cvs 9503: </li>
1.18 cvs 9504: <li>
9505: <tt>V</tt>: a down arrow as tall as the box and in its middle
1.19 cvs 9506: </li>
1.18 cvs 9507: <li>
9508: w: a segment (2 points)
1.19 cvs 9509: </li>
1.18 cvs 9510: <li>
9511: <tt>W</tt>: the upper right corner
1.19 cvs 9512: </li>
1.18 cvs 9513: <li>
9514: x: a segment (2 points) with an arrow head at the end
1.19 cvs 9515: </li>
1.18 cvs 9516: <li>
9517: <tt>X</tt>: the lower right corner
1.19 cvs 9518: </li>
1.18 cvs 9519: <li>
9520: y: a segment (2 points) with an arrow head at the end
1.19 cvs 9521: </li>
1.18 cvs 9522: <li>
9523: <tt>Y</tt>: the lower left corner
1.19 cvs 9524: </li>
1.18 cvs 9525: <li>
9526: z: a segment (2 points) with an arrow head at the end
1.19 cvs 9527: </li>
1.18 cvs 9528: <li>
9529: <tt>Z</tt>: the upper left corner
1.19 cvs 9530: </li>
1.18 cvs 9531: <li>
9532: <tt>space</tt>: a transparent element
1.19 cvs 9533: </li>
1.18 cvs 9534: <li>
9535: <tt>^</tt>: an up arrow as tall as the box and in its middle
1.19 cvs 9536: </li>
1.18 cvs 9537: <li>
9538: <tt>></tt>: a right arrow as long as the box's width and in its middle
1.19 cvs 9539: </li>
1.18 cvs 9540: <li>
9541: <tt>></tt>: a left arrow as long as the box's width and in its middle
1.19 cvs 9542: </li>
1.18 cvs 9543: <li>
9544: <tt>/</tt>: The southwest/northeast diagonal of the box
1.19 cvs 9545: </li>
1.18 cvs 9546: <li>
9547: <tt>\</tt>: the northwest/southeast diagonal of the box
1.19 cvs 9548: </li>
1.18 cvs 9549: </ul>
9550: <hr>
1.19 cvs 9551:
1.18 cvs 9552: </div>
9553: </div>
9554: </body>
9555: </html>
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