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1.30 cvs 6: <title>The Languages of Thot</title>
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1.19 cvs 12: <div class="frontmatter" align="center">
1.18 cvs 13: <h1>The Languages of Thot</h1>
14:
15: <h3>Vincent Quint</h3>
16:
17: <h4>Translated from French by Ethan Munson</h4>
18:
1.38 ! cvs 19: <h4>Version of May 21, 2001</h4>
1.30 cvs 20:
1.37 cvs 21: <p>© 1996-2001 INRIA</p>
22: <hr />
1.18 cvs 23: </div>
24:
25: <div class="tableofcontents">
26: <h2><a href="languages.toc.html">Contents</a></h2>
27: <ul>
1.37 cvs 28: <li><big><a href="#sect2">The document model of Thot</a></big>
1.30 cvs 29: <ul>
30: <li><strong><a href="#sectb21">The logical structure of
31: documents</a></strong></li>
32: <li><strong><a href="#sectb22">Generic and specific
33: structures</a></strong></li>
34: <li><strong><a href="#sectb23">Logical structure and physical
35: structure</a></strong></li>
36: <li><strong><a href="#sectb24">Document structures and object
37: structures</a></strong></li>
38: </ul>
39: </li>
1.37 cvs 40: <li><big><a href="#sect3">The S language</a></big>
1.30 cvs 41: <ul>
1.37 cvs 42: <li><strong><a href="#sectb31">Document meta-structure</a></strong>
1.30 cvs 43: <ul>
44: <li><a href="#sectc311">The basic types</a></li>
45: <li><a href="#sectc312">Constructed elements</a></li>
1.37 cvs 46: <li><a href="#sectc313">Logical structure constructors</a>
1.30 cvs 47: <ul>
48: <li><small><a href="#sectd3131">Aggregate and
49: List</a></small></li>
50: <li><small><a href="#sectd3132">Choice, Schema, and
51: Unit</a></small></li>
52: <li><small><a href="#sectd3133">Reference and
53: Inclusion</a></small></li>
54: <li><small><a href="#sectd3134">Mark pairs</a></small></li>
55: <li><small><a href="#sectd3135">Restrictions and
56: Extensions</a></small></li>
57: <li><small><a href="#sectd3136">Summary</a></small></li>
58: </ul>
59: </li>
60: <li><a href="#sectc315">Attributes</a></li>
61: <li><a href="#sectc316">Discussion of the model</a></li>
62: </ul>
63: </li>
64: <li><strong><a href="#sectb32">The definition language for generic
1.37 cvs 65: structures</a></strong>
1.30 cvs 66: <ul>
67: <li><a href="#sectc321">Writing Conventions</a></li>
68: <li><a href="#sectc322">Extension schemas</a></li>
69: <li><a href="#sectc323">The general organization of structure
70: schemas</a></li>
71: <li><a href="#sectc324">The default presentation</a></li>
72: <li><a href="#sectc325">Global Attributes</a></li>
73: <li><a href="#sectc327">Structured elements</a></li>
1.37 cvs 74: <li><a href="#sectc328">Structure definitions</a>
1.30 cvs 75: <ul>
76: <li><small><a href="#sectd3281">List</a></small></li>
77: <li><small><a href="#sectd3282">Aggregate</a></small></li>
78: <li><small><a href="#sectd3283">Choice</a></small></li>
79: <li><small><a href="#sectd3284">Reference</a></small></li>
80: <li><small><a href="#sectd3285">Mark pairs</a></small></li>
81: </ul>
82: </li>
83: <li><a href="#sectc329">Imports</a></li>
84: <li><a href="#sectc3210">Extension rules</a></li>
85: <li><a href="#sectc3212">Units</a></li>
86: <li><a href="#sectc3213">Skeleton elements</a></li>
87: <li><a href="#sectc3214">Exceptions</a></li>
88: </ul>
89: </li>
1.37 cvs 90: <li><strong><a href="#sectb33">Some examples</a></strong>
1.30 cvs 91: <ul>
92: <li><a href="#sectc331">A class of documents: articles</a></li>
93: <li><a href="#sectc332">A class of objects: mathematical
94: formulas</a></li>
95: </ul>
96: </li>
97: </ul>
98: </li>
1.37 cvs 99: <li><big><a href="#sect4">The P language</a></big>
1.30 cvs 100: <ul>
1.37 cvs 101: <li><strong><a href="#sectb41">Document presentation</a></strong>
1.30 cvs 102: <ul>
103: <li><a href="#sectc411">Two levels of presentation</a></li>
104: <li><a href="#sectc412">Boxes</a></li>
105: <li><a href="#sectc413">Views and visibility</a></li>
106: <li><a href="#sectc414">Pages</a></li>
107: <li><a href="#sectc415">Numbering</a></li>
1.34 cvs 108: <li><a href="#sectc416">Presentation properties</a></li>
1.30 cvs 109: </ul>
110: </li>
111: <li><strong><a href="#sectb42">Presentation description
1.37 cvs 112: language</a></strong>
1.30 cvs 113: <ul>
114: <li><a href="#sectc421">The organization of a presentation
115: schema</a></li>
116: <li><a href="#sectc422">Views</a></li>
117: <li><a href="#sectc423">Print Views</a></li>
118: <li><a href="#sectc424">Counters</a></li>
119: <li><a href="#sectc425">Presentation constants</a></li>
120: <li><a href="#sectc426">Variables</a></li>
121: <li><a href="#sectc427">Default presentation rules</a></li>
122: <li><a href="#sectc428">Presentation and page layout boxes</a></li>
123: <li><a href="#sectc429">Presentation of structured elements</a></li>
124: <li><a href="#sectc4210">Logical attribute presentation</a></li>
125: <li><a href="#sectc4212">Value transmission rules</a></li>
126: <li><a href="#sectc4213">Presentation rules</a></li>
127: <li><a href="#sectc4214">Conditions applying to presentation
1.37 cvs 128: rules</a>
1.30 cvs 129: <ul>
1.37 cvs 130: <li><small><a href="#sectd42141">Conditions based on the
131: logical position of the element</a></small></li>
1.30 cvs 132: <li><small><a href="#sectd42142">Conditions on
133: references</a></small></li>
134: <li><small><a href="#sectd42143">Conditions on logical
135: attributes</a></small></li>
136: <li><small><a href="#sectd42144">Conditions on page
137: breaks</a></small></li>
138: <li><small><a href="#sectd42145">Conditions on the element's
139: content</a></small></li>
140: <li><small><a href="#sectd42146">Conditions on
141: counters</a></small></li>
142: </ul>
143: </li>
144: <li><a href="#sectc4215">A presentation rule</a></li>
145: <li><a href="#sectc4216">Box axes</a></li>
146: <li><a href="#sectc4217">Distance units</a></li>
147: <li><a href="#sectc4218">Relative positions</a></li>
1.37 cvs 148: <li><a href="#sectc4219">Box extents</a>
1.30 cvs 149: <ul>
150: <li><small><a href="#sectd42191">Fixed extents</a></small></li>
151: <li><small><a href="#sectd42192">Relative
152: extents</a></small></li>
153: <li><small><a href="#sectd42193">Elastic
154: extents</a></small></li>
155: </ul>
156: </li>
157: <li><a href="#sectc4220">Overflow</a></li>
158: <li><a href="#sectc4221">Inheritance</a></li>
1.37 cvs 159: <li><a href="#sectc4222">Line breaking</a>
1.30 cvs 160: <ul>
161: <li><small><a href="#sectd42221">Line spacing</a></small></li>
162: <li><small><a href="#sectd42222">First line
163: indentation</a></small></li>
164: <li><small><a href="#sectd42223">Alignment</a></small></li>
165: <li><small><a href="#sectd42225">Hyphenation</a></small></li>
166: <li><small><a href="#sectd42226">Avoiding line
167: breaking</a></small></li>
168: </ul>
169: </li>
170: <li><a href="#sectc4223">Page breaking and line breaking
171: conditions</a></li>
172: <li><a href="#sectc4224">Visibility</a></li>
1.37 cvs 173: <li><a href="#sectc4225">Character style properties</a>
1.30 cvs 174: <ul>
175: <li><small><a href="#sectd42251">Character size</a></small></li>
176: <li><small><a href="#sectd42252">Font and character
177: style</a></small></li>
178: <li><small><a href="#sectd42253">Underlining</a></small></li>
179: </ul>
180: </li>
181: <li><a href="#sectc4226">Stacking order</a></li>
182: <li><a href="#sectc4227">Line style</a></li>
183: <li><a href="#sectc4228">Line thickness</a></li>
184: <li><a href="#sectc4229">Fill pattern</a></li>
185: <li><a href="#sectc4230">Colors</a></li>
186: <li><a href="#sectc4230a">Background color and border</a></li>
187: <li><a href="#sectc4230b">Background pictures</a></li>
188: <li><a href="#sectc4231">Presentation box content</a></li>
189: <li><a href="#sectc4232">Presentation box creation</a></li>
190: <li><a href="#sectc4233">Page layout</a></li>
191: <li><a href="#sectc4234">Box copies</a></li>
192: </ul>
193: </li>
194: </ul>
195: </li>
1.37 cvs 196: <li><big><a href="#sect5">The T language</a></big>
1.30 cvs 197: <ul>
1.37 cvs 198: <li><strong><a href="#sectb51">Document translation</a></strong>
1.30 cvs 199: <ul>
200: <li><a href="#sectc511">Translation principles</a></li>
201: <li><a href="#sectc512">Translation procedure</a></li>
202: </ul>
203: </li>
204: <li><strong><a href="#sectb52">Translation definition
1.37 cvs 205: language</a></strong>
1.30 cvs 206: <ul>
207: <li><a href="#sectc521">Organization of a translation
208: schema</a></li>
209: <li><a href="#sectc522">Line length</a></li>
210: <li><a href="#sectc523">Buffers</a></li>
211: <li><a href="#sectc524">Counters</a></li>
212: <li><a href="#sectc525">Constants</a></li>
213: <li><a href="#sectc526">Variables</a></li>
214: <li><a href="#sectc527">Translating structure elements</a></li>
1.37 cvs 215: <li><a href="#sectc528">Conditional rules</a>
1.30 cvs 216: <ul>
217: <li><small><a href="#sectd5281">Conditions based on the logical
218: position of the element</a></small></li>
219: <li><small><a href="#sectd5282">Conditions on
220: references</a></small></li>
221: <li><small><a href="#sectd5284">Conditions on the
222: alphabets</a></small></li>
223: <li><small><a href="#sectd5285">Conditions on page
224: breaks</a></small></li>
225: <li><small><a href="#sectd5286">Conditions on the element's
226: content</a></small></li>
227: <li><small><a href="#sectd5288">Conditions on the presence of
228: specific presentation rules</a></small></li>
229: <li><small><a href="#sectd5289">Conditions on the presence of
230: logical attributes</a></small></li>
231: <li><small><a href="#sectd52810">Conditions on logical
232: attributes</a></small></li>
233: <li><small><a href="#sectd52811">Conditions on specific
234: presentation rules</a></small></li>
235: </ul>
236: </li>
237: <li><a href="#sectc529">Translation rules</a></li>
238: <li><a href="#sectc5210">The <tt>Create</tt> rule</a></li>
239: <li><a href="#sectc5211">The <tt>Write</tt> rule</a></li>
240: <li><a href="#sectc5212">The <tt>Read</tt> rule</a></li>
241: <li><a href="#sectc5213">The <tt>Include</tt> rule</a></li>
242: <li><a href="#sectc5214">The <tt>Get</tt> rule</a></li>
243: <li><a href="#sectc5215">The <tt>Copy</tt> rule</a></li>
244: <li><a href="#sectc5216">The <tt>Use</tt> rule</a></li>
245: <li><a href="#sectc5217">The <tt>Remove</tt> rule</a></li>
1.31 cvs 246: <li><a href="#sectc5217a">The <code>Ignore</code> rule</a></li>
1.30 cvs 247: <li><a href="#sectc5218">The <tt>NoTranslation</tt> rule</a></li>
248: <li><a href="#sectc5219">The <tt>NoLineBreak</tt> rule</a></li>
249: <li><a href="#sectc5220">The <tt>ChangeMainFile</tt> rule</a></li>
250: <li><a href="#sectc5220a">The <tt>RemoveFile</tt> rule</a></li>
251: <li><a href="#sectc5221">The <tt>Set</tt> and <tt>Add</tt>
252: rules</a></li>
253: <li><a href="#sectc5221a">The <tt>Indent</tt> rule</a></li>
254: <li><a href="#sectc5222">Rule application order</a></li>
255: <li><a href="#sectc5223">Translation of logical attributes</a></li>
256: <li><a href="#sectc5224">Translation of specific
257: presentations</a></li>
258: <li><a href="#sectc5225">Recoding of characters, symbols and
259: graphics</a></li>
260: </ul>
261: </li>
262: </ul>
263: </li>
1.37 cvs 264: <li><big><a href="#sect6">Language grammars</a></big>
1.30 cvs 265: <ul>
266: <li><strong><a href="#sectb61">The M meta-language</a></strong></li>
267: <li><strong><a href="#sectb62">The S language</a></strong></li>
268: <li><strong><a href="#sectb63">The P language</a></strong></li>
269: <li><strong><a href="#sectb64">The T language</a></strong></li>
270: </ul>
271: </li>
1.37 cvs 272: <li><big><a href="#sect7">Character coding</a></big>
1.30 cvs 273: <ul>
274: <li><strong><a href="#sectb71">Characters</a></strong></li>
275: <li><strong><a href="#sectb72">Symbols</a></strong></li>
276: <li><strong><a href="#sectb73">Graphical elements</a></strong></li>
277: </ul>
278: </li>
1.18 cvs 279: </ul>
1.37 cvs 280: <hr />
1.18 cvs 281: </div>
1.1 cvs 282:
1.18 cvs 283: <div class="chapter">
1.37 cvs 284: <h1><a name="sect2" id="sect2">The document model of Thot</a></h1>
1.1 cvs 285:
1.30 cvs 286: <p>All of the services which Thot provides to the user are based on the
1.37 cvs 287: system's internal document representation. This representation is itself
288: derived from the document model which underlies Thot. The model is presented
1.30 cvs 289: here, prior to the description of the languages which permit the generic
290: specification of documents.</p>
1.1 cvs 291:
1.18 cvs 292: <div class="section">
1.37 cvs 293: <h2><a name="sectb21" id="sectb21">The logical structure of documents</a></h2>
1.1 cvs 294:
1.30 cvs 295: <p>The document model of Thot is primarily designed to allow the user to
296: operate on those entities which s/he has in mind when s/he works on a
297: document. The model makes no assumptions about the nature of these entities.
298: It is essentially these logical entities, such as paragraphs, sections,
299: chapters, notes, titles, and cross-references which give a document its
300: logical structure.</p>
301:
302: <p>Because of this model, the author can divide the document into chapters,
1.37 cvs 303: giving each one a title. The content of these chapters can be further divided
304: into sections, subsections, etc. The text is organized into successive
1.2 cvs 305: paragraphs, according to the content. In the writing phase, the lines, pages,
1.37 cvs 306: margins, spacing, fonts, and character styles are not very important. In
307: fact, if the system requires documents to be written in these terms, it gets
308: in the way. So, Thot's model is primarily based on the logical aspect of
309: documents. The creation of a model of this type essentially requires the
310: definition :</p>
1.18 cvs 311: <ul>
1.30 cvs 312: <li>of the entities which can appear in the documents,</li>
313: <li>and the relations between these entities.</li>
1.18 cvs 314: </ul>
1.30 cvs 315:
1.37 cvs 316: <p>The choice of entities to include in the model can be subtle. Some
317: documents require chapters, while others only need various levels of
318: sections. Certain documents contain appendices, others don't. In different
319: documents the same logical entity may go by different names (e.g.
320: ``Conclusion'' and ``Summary''). Certain entities which are absolutely
321: necessary in some documents, such as clauses in a contract or the address of
322: the recipient in a letter, are useless in most other cases.</p>
1.30 cvs 323:
324: <p>The differences between documents result from more than just the entities
325: that appear in them, but also from the relationships between these entities
1.37 cvs 326: and the ways that they are linked. In certain documents, notes are spread
1.30 cvs 327: throughout the document, for example at the bottom of the page containing the
1.1 cvs 328: cross-reference to them, while in other documents they are collected at the
1.37 cvs 329: end of each chapter or even at the end of the work. As another example, the
1.1 cvs 330: introduction of some documents can contain many sections, while in other
331: documents, the introduction is restricted to be a short sequence of
1.18 cvs 332: paragraphs.</p>
1.30 cvs 333:
1.37 cvs 334: <p>All of this makes it unlikely that a single model can describe any
335: document at a relatively high level. It is obviously tempting to make up a
336: list of widely used entities, such as chapters, sections, paragraphs, and
337: titles, and then map all other entities onto the available choices. In this
338: way, an introduction can be supported as a chapter and a contract clause
339: supported as a paragraph or section. However, in trying to widen the range of
340: usage of certain entities, their meaning can be lost and the power of the
341: model reduced. In addition, while this widening partially solves the problem
342: of choosing entities, it does not solve the problem of their organization:
343: when a chapter must be composed of sections, how does one indicate that an
344: introduction has none when it is merely another chapter? One solution is to
1.1 cvs 345: include introductions in the list of supported entities. But then, how does
346: one distinguish those introductions which are allowed to have sections from
1.37 cvs 347: those which are not. Perhaps this could be done by defining two types of
1.1 cvs 348: introduction. Clearly, this approach risks an infinite expansion of the list
1.18 cvs 349: of widely used entities.</p>
350: </div>
1.1 cvs 351:
1.18 cvs 352: <div class="section">
1.37 cvs 353: <h2><a name="sectb22" id="sectb22">Generic and specific structures</a></h2>
1.1 cvs 354:
1.30 cvs 355: <p>Thus, it is apparently impossible to construct an exhaustive inventory of
356: all those entities which are necessary and sufficient to precisely describe
1.37 cvs 357: any document. It also seems impossible to specify all possible arrangements
358: of these entities in a document. This is why Thot uses a <em>meta-model</em>
1.18 cvs 359: instead, which permits the description of numerous <em>models</em>, each one
360: describing a <em>class</em> of documents.</p>
1.30 cvs 361:
1.37 cvs 362: <p>A <em>class</em> is a set of documents having very similar structure.
363: Thus, the collection of research reports published by a laboratory
364: constitutes a class; the set of commercial proposals by the sales department
365: of a company constitutes another class; the set of articles published by a
366: journal constitutes a third class. Clearly, it is not possible to enumerate
367: every possible document class. It is also clear that new document classes
368: must be created to satisfy new needs and applications.</p>
1.30 cvs 369:
370: <p>To give a more rigorous definition of classes, we must introduce the ideas
1.37 cvs 371: of <em>generic structure</em> and <em>specific structure</em>. Each document
1.30 cvs 372: has a <em>specific structure</em> which organizes the various parts which
1.37 cvs 373: comprise it. We illustrate this with the help of a simple example comparing
1.30 cvs 374: two reports, A and B (<a href="#specstruct">see Figure</a>). The report A
1.37 cvs 375: contains an introduction followed by three chapters and a conclusion. The
376: first chapter contains two sections, the second, three sections. That is the
1.18 cvs 377: <em>specific</em> structure of document A. Similarly, the structure of
1.1 cvs 378: document B is: an introduction, two chapters, a conclusion; Chapter 1 has
1.37 cvs 379: three sections while Chapter 2 has four. The specific structures of these two
1.18 cvs 380: documents are thus different.</p>
1.1 cvs 381:
1.18 cvs 382: <div class="figure">
1.37 cvs 383: <hr />
1.18 cvs 384: <pre> Report A Report B
1.1 cvs 385: Introduction Introduction
386: Chapter 1 Chapter 1
387: Section 1.1 Section 1.1
388: Section 1.2 Section 1.2
389: Chapter 2 Section 1.3
390: Section 2.1 Chapter 2
391: Section 2.2 Section 2.1
392: Section 2.3 Section 2.2
393: Chapter 3 Section 2.3
394: Conclusion Section 2.4
1.18 cvs 395: Conclusion</pre>
1.30 cvs 396:
1.37 cvs 397: <p align="center"><em><a name="specstruct" id="specstruct">Two specific
1.30 cvs 398: structures</a></em></p>
1.37 cvs 399: <hr />
1.30 cvs 400: </div>
401:
402: <p>The <em>generic structure</em> defines the ways in which specific
1.37 cvs 403: structures can be constructed. It specifies how to generate specific
404: structures. The reports A and B, though different, are constructed in
1.30 cvs 405: accordance with the same generic structure, which specifies that a report
406: contains an introduction followed by a variable number of chapters and a
407: conclusion, with each chapter containing a variable number of sections.</p>
408:
409: <p>There is a one-to-one correspondence between a class and a generic
1.37 cvs 410: structure: all the documents of a class are constructed in accordance with
411: the same generic structure. Hence the definition of the class: a class is a
412: set of documents whose specific structure is constructed in accordance with
413: the same generic structure. A class is characterized by its generic
1.30 cvs 414: structure.</p>
1.19 cvs 415:
1.30 cvs 416: <p>Thus, a generic structure can be considered to be a model at the level
1.37 cvs 417: which interests us, but only for one class of documents. When the definition
1.30 cvs 418: is limited to a single class of documents, it is possible to define a model
419: which does a good job of representing the documents of the class, including
1.37 cvs 420: the necessary entities and unencumbered by useless entities. The description
1.30 cvs 421: of the organization of the documents in the class can then be sufficiently
1.18 cvs 422: precise.</p>
423: </div>
1.1 cvs 424:
1.18 cvs 425: <div class="section">
1.37 cvs 426: <h2><a name="sectb23" id="sectb23">Logical structure and physical
427: structure</a></h2>
1.1 cvs 428:
1.30 cvs 429: <p>Generic structures only describe the <em>logical</em> organization of
1.18 cvs 430: documents, not their <em>physical</em> presentation on a screen or on sheets
1.37 cvs 431: of paper. However, for a document to be displayed or printed, its graphic
1.18 cvs 432: presentation must be taken into account.</p>
1.30 cvs 433:
434: <p>An examination of current printed documents shows that the details of
1.1 cvs 435: presentation essentially serve to bring out their logical structure. Outside
436: of some particular domains, notably advertising, the presentation is rarely
1.37 cvs 437: independent of the logical organization of the text. Moreover, the art of
1.1 cvs 438: typography consists of enhancing the organization of the text being set,
1.37 cvs 439: without catching the eye of the reader with overly pronounced effects. Thus,
440: italic and boldface type are used to emphasize words or expressions which
441: have greater significance than the rest of the text: keywords, new ideas,
442: citations, book titles, etc. Other effects highlight the organization of the
1.1 cvs 443: text: vertical space, margin changes, page breaks, centering, eventually
444: combined with the changes in the shapes or weight of the characters. These
445: effects serve to indicate the transitions between paragraphs, sections, or
446: chapters: an object's level in the logical structure of the document is shown
1.18 cvs 447: by the markedness of the effects.</p>
1.30 cvs 448:
449: <p>Since the model permits the description of all of the logical structure of
450: the document, the presentation can be derived from the model without being
1.37 cvs 451: submerged in the document itself. It suffices to use the logical structure of
1.1 cvs 452: the document to make the desired changes in its presentation: changes in type
1.18 cvs 453: size, type style, spacing, margin, centering, etc.</p>
1.30 cvs 454:
455: <p>Just as one cannot define a unique generic logical structure for all
456: document classes, one cannot define universal presentation rules which can be
1.37 cvs 457: applied to all document classes. For certain types of documents the chapter
458: titles will be centered on the page and printed in large, bold type. For
459: other documents, the same chapter titles will be printed in small, italic
460: type and aligned on the left margin.</p>
1.30 cvs 461:
462: <p>Therefore, it is necessary to base the presentation specifications for
1.37 cvs 463: documents on their class. Such a specification can be very fine-grained,
1.1 cvs 464: because the presentation is expressed in terms of the entities defined in the
1.37 cvs 465: generic logical structure of the class. Thus, it is possible to specify a
1.1 cvs 466: different presentation for the chapter titles and the section titles, and
467: similarly to specify titles for the sections according to their level in the
1.37 cvs 468: section hierarchy. The set of rules which specify the presentation of all the
1.18 cvs 469: elements defined in a generic logical structure is called a <em>generic
470: presentation</em>.</p>
1.30 cvs 471:
472: <p>There are several advantages derived from having a presentation linked to
473: the generic structure and described by a generic presentation. Homogeneity is
1.37 cvs 474: the first. Since every document in a class corresponds to the same generic
1.1 cvs 475: logical structure, a homogenous presentation for different documents of the
476: same class can be assured by applying the same generic presentation to all
1.37 cvs 477: documents of the class. Homogeneity of presentation can also be found among
478: the entities of a single document: every section heading will be presented in
479: the same way, the first line of every paragraph of the same type will have
480: the same indentation, etc.</p>
1.30 cvs 481:
482: <p>Another advantage of this approach to presentation is that it facilitates
1.37 cvs 483: changes to the graphical aspect of documents. A change to the generic
484: presentation rules attached to each type of entity will alter the
485: presentation of the entire document, and will do so homogenously. In this
486: case, the internal homogeneity of the class is no longer assured, but the way
487: to control it is simple. It suffices to adopt a single generic presentation
488: for the entire class.</p>
1.30 cvs 489:
490: <p>If the presentation of the class does not have to be homogenous, then the
1.37 cvs 491: appearance of the document can be adapted to the way it will be used or to
492: the device used to render it. This quality is sufficient to allow the
493: existence of <a name="mulpres" id="mulpres">many generic presentations</a>
494: for the same document class. By applying one or the other of these
495: presentations to it, the document can be seen under different graphical
496: aspects. It must be emphasized that this type of modification of the
497: presentation is not a change to the document itself (in its specific logical
498: structure or its content), but only in its appearance at the time of editing
499: or printing.</p>
1.18 cvs 500: </div>
1.1 cvs 501:
1.18 cvs 502: <div class="section">
1.37 cvs 503: <h2><a name="sectb24" id="sectb24">Document structures and object
504: structures</a></h2>
1.1 cvs 505:
1.30 cvs 506: <p>So far, we have only discussed the global structure of documents and have
1.37 cvs 507: not considered the contents found in that structure. We could limit ourselves
1.30 cvs 508: to purely textual contents by assuming that a title or a paragraph contains a
1.37 cvs 509: simple linear text. But this model would be too restrictive. In fact, certain
510: documents contain not only text, but also contain tables, diagrams,
511: photographs, mathematical formulas, and program fragments. The model must
1.18 cvs 512: permit the representation of such <em>objects</em>.</p>
1.30 cvs 513:
514: <p>Just as with the whole of the document, the model takes into account the
1.37 cvs 515: logical structure of objects of this type. Some are clearly structured,
516: others are less so. Logical structure can be recognized in mathematical
517: formulas, in tables, and in certain types of diagrams. On the other hand, it
518: is difficult to define the structure of a photograph or of some drawings. But
1.1 cvs 519: in any case, it does not seem possible to define one unique structure which
1.37 cvs 520: can represent every one of these types of objects. The approach taken in the
1.1 cvs 521: definition of meta-structure and document classes also applies to objects.
522: Object classes can be defined which put together objects of similar type,
1.18 cvs 523: constructed from the same generic logical structure.</p>
1.30 cvs 524:
525: <p>Thus, a mathematical class can be defined and have a generic logical
1.37 cvs 526: structure associated with it. But even if a single generic structure can
1.30 cvs 527: represent a sufficient variety of mathematical formulas, for other objects
1.37 cvs 528: with less rigorous structure, multiple classes must be defined. As for
529: documents, using multiple classes assures that the model can describe the
530: full range of objects to be presented. It also permits the system to support
531: objects which were not initially anticipated. Moreover, this comment applies
1.30 cvs 532: equally to mathematics: different classes of formulas can be described
533: depending on the domain of mathematics being described.</p>
534:
535: <p>Since objects have the same level of logical representation as documents,
1.37 cvs 536: they gain the same advantages. In particular, it is possible to define the
1.1 cvs 537: presentation separately from the objects themselves and attach it to the
1.37 cvs 538: class. Thus, as for documents, objects of the same type have a uniform
1.1 cvs 539: presentation and the presentation of every object in a given class can be
1.37 cvs 540: changed simply by changing the generic presentation of the class. Another
1.1 cvs 541: advantage of using this document model is that the system does not bother the
542: user with the details of presentation, but rather allows the user to
1.18 cvs 543: concentrate on the logical aspect of the document and the objects.</p>
1.30 cvs 544:
545: <p>It is clear that the documents in a class do not necessarily use the same
1.1 cvs 546: classes of objects: one technical report will contain tables while another
547: report will have no tables but will use mathematical formulas. The usable
1.2 cvs 548: object classes are not always mentioned in a limiting way in the generic
1.37 cvs 549: logical structure of documents. Rather, they can be chosen freely from a
1.18 cvs 550: large set, independent of the document class.</p>
1.30 cvs 551:
552: <p>Thus, the object classes will be made commonplace and usable in every
1.1 cvs 553: document. The notion of ``object'' can be enlarged to include not only
554: non-textual elements, but also certain types of textual elements which can
1.37 cvs 555: appear in practically every document, whatever their class. Among these
1.2 cvs 556: textual elements, one can mention enumerations, descriptions, examples,
1.18 cvs 557: quotations, even paragraphs.</p>
1.30 cvs 558:
559: <p>Thus, the document model is not a single, general model describing every
1.37 cvs 560: type of document in one place. Rather, it is a meta-model which can be used
1.30 cvs 561: to describe many different models each of which represents either a class of
1.1 cvs 562: similar documents or a class of similar objects which every document can
1.18 cvs 563: include.</p>
564: </div>
1.37 cvs 565: <hr />
1.18 cvs 566: </div>
1.1 cvs 567:
1.18 cvs 568: <div class="chapter">
1.37 cvs 569: <h1><a name="sect3" id="sect3">The S language</a></h1>
1.1 cvs 570:
1.18 cvs 571: <div class="section">
1.37 cvs 572: <h2><a name="sectb31" id="sectb31">Document meta-structure</a></h2>
1.1 cvs 573:
1.30 cvs 574: <p>Since the concept of meta-structure is well suited to the task of
575: describing documents at a high level of abstraction, this meta-structure must
1.37 cvs 576: be precisely defined. Toward that end this section first presents the basic
1.1 cvs 577: elements from which documents and structured objects are composed and then
1.37 cvs 578: specifies the ways in which these basic elements are assembled into
579: structures representing complete documents and objects.</p>
1.1 cvs 580:
1.18 cvs 581: <div class="subsection">
1.37 cvs 582: <h3><a name="sectc311" id="sectc311">The basic types</a></h3>
1.1 cvs 583:
1.37 cvs 584: <p>At the lowest level of a document's structure, the first atom considered
585: is the character. However, since characters are seldom isolated, usually
1.1 cvs 586: appearing as part of a linear sequence, and in order to reduce the complexity
1.18 cvs 587: of the document structure, <em>character strings</em> are used as atoms and
1.37 cvs 588: consecutive characters belonging to the same structural element are grouped
589: in the same character string.</p>
1.30 cvs 590:
1.37 cvs 591: <p>If the structure of a document is not refined to go down to the level of
592: words or phrases, the contents of a simple paragraph can be considered to be
593: a single character string. On the other hand, the title of a chapter, the
594: title of the first section of that chapter, and the text of the first
595: paragraph of that section constitute three different character strings,
596: because they belong to distinct structural elements.</p>
1.30 cvs 597:
598: <p>If, instead, a very fine-grained representation for the structure of a
1.1 cvs 599: document is sought, character strings could be defined to contain only a
1.37 cvs 600: single word, or even just a single character. This is the case, for example,
601: in programs, for which one wants to retain a structure very close to the
602: syntax of the programming language. In this case, an assignment statement
1.1 cvs 603: initializing a simple variable to zero would be composed of two structural
604: elements, the identifier of the variable (a short character string) and the
1.18 cvs 605: assigned value (a string of a single character, `0').</p>
1.30 cvs 606:
607: <p>The character string is not the only atom necessary for representing those
1.37 cvs 608: documents that interest us. It suffices for purely textual documents, but as
1.1 cvs 609: soon as the non-textual objects which we have considered arise, there must be
610: other atoms; the number of objects which are to be represented determines the
1.18 cvs 611: number of types of atoms that are necessary.</p>
1.30 cvs 612:
613: <p>Primitive <em>graphical elements</em> are used for tables and figures of
1.37 cvs 614: different types. These elements are simple geometric shapes like horizontal
1.1 cvs 615: or vertical lines, which are sufficient for tables, or even oblique lines,
1.2 cvs 616: arrows, rectangles, circles, polygons, and curves for use in figures. From
617: these elements and character strings, graphical objects and tables can be
1.18 cvs 618: constructed.</p>
1.30 cvs 619:
620: <p>Photographs, though having very little structure, must still appear in
1.37 cvs 621: documents. They are supported by <em>picture</em> elements, which are
1.18 cvs 622: represented as matrices of pixels.</p>
1.30 cvs 623:
624: <p>Finally, mathematical notations require certain elements which are
1.37 cvs 625: simultaneously characters and graphical elements, the <em>symbols</em>. By
626: way of example, radicals, integration signs, or even large parentheses are
627: examples of this type of atom. The size of each of these symbols is
1.1 cvs 628: determined by its environment, that is to say, by the expression to which it
1.18 cvs 629: is attached.</p>
1.30 cvs 630:
631: <p>To summarize, the primitive elements which are used in the construction of
1.18 cvs 632: documents and structured objects are:</p>
633: <ul>
1.30 cvs 634: <li>character strings,</li>
635: <li>graphical elements,</li>
636: <li>pictures,</li>
637: <li>and mathematical symbols.</li>
1.18 cvs 638: </ul>
639: </div>
1.1 cvs 640:
1.18 cvs 641: <div class="subsection">
1.37 cvs 642: <h3><a name="sectc312" id="sectc312">Constructed elements</a></h3>
1.30 cvs 643:
1.37 cvs 644: <p>A document is evidently formed from primitive elements. But the model of
645: Thot also proposes higher level elements. Thus, in a document composed of
646: several chapters, each chapter is an element, and in the chapters each
647: section is also an element, and so on. A document is thus an organized set of
1.30 cvs 648: elements.</p>
1.1 cvs 649:
1.37 cvs 650: <p>In a document there are different sorts of elements. Each element has a
651: <em>type</em> which indicates the role of the element within the document as
652: a whole. Thus, we have, for example, the chapter and section types. The
1.1 cvs 653: document is made up of typed elements: elements of the type chapter and
1.37 cvs 654: elements of the type section, among others, but also character string
655: elements and graphical elements: the primitive elements are typed elements
656: just as well. At the other extreme, the document itself is also considered to
657: be a typed element.</p>
1.30 cvs 658:
659: <p>The important difference between the primitive elements and the other
1.37 cvs 660: elements of the document is that the primitive elements are atoms (they
661: cannot be decomposed), whereas the others, called <em>constructed
662: elements</em>, are composed of other elements, which can either be primitive
663: elements or constructed elements. A constructed element of type chapter (or
664: more simply, ``a chapter'') is composed of sections, which are also
665: constructed elements. A paragraph, a constructed element, can be made up of
666: character strings, which are primitive elements, and of equations, which are
667: constructed elements.</p>
1.30 cvs 668:
1.37 cvs 669: <p>A document is also a constructed element. This is an important point. In
1.1 cvs 670: particular, it allows a document to be treated as part of another document,
671: and conversely, permits a part of a document to be treated as a complete
1.37 cvs 672: document. Thus, an article presented in a journal is treated by its author as
1.1 cvs 673: a document in itself, while the editor of the journal considers it to be part
1.37 cvs 674: of an issue. A table or a figure appearing in a document can be extracted and
1.1 cvs 675: treated as a complete document, for example to prepare transparencies for a
1.18 cvs 676: conference.</p>
1.30 cvs 677:
678: <p>These thoughts about types and constructed elements apply just as well to
1.37 cvs 679: objects as they do to documents. A table is a constructed element made up of
680: other constructed elements, rows and columns. A row is formed of cells, which
1.1 cvs 681: are also constructed elements which contain primitive elements (character
1.18 cvs 682: strings) and/or constructed elements like equations.</p>
683: </div>
1.1 cvs 684:
1.18 cvs 685: <div class="subsection">
1.37 cvs 686: <h3><a name="sectc313" id="sectc313">Logical structure constructors</a></h3>
1.1 cvs 687:
1.30 cvs 688: <p>Having defined the primitive elements and the constructed elements, it is
689: now time to define the types of organization which allow the building of
1.37 cvs 690: structures. For this, we rely on the notion of the <em>constructor</em>. A
691: constructor defines a way of assembling certain elements in a structure. It
1.1 cvs 692: resides at the level of the meta-structure: it does not describe the existing
1.37 cvs 693: relations in a given structure, but rather defines how elements are assembled
1.18 cvs 694: to build a structure that conforms to a model.</p>
1.30 cvs 695:
696: <p>In defining the overall organization of documents, the first two
697: constructors considered are the aggregate and the list.</p>
1.1 cvs 698:
1.18 cvs 699: <div class="subsubsection">
1.37 cvs 700: <h4><a name="sectd3131" id="sectd3131">Aggregate and List</a></h4>
1.1 cvs 701:
1.30 cvs 702: <p>The <em>aggregate</em> constructor is used to define constructed element
703: types which are collections of a given number of other elements. These
1.37 cvs 704: collections may or may not be ordered. The elements may be either constructed
705: or primitive and are specified by their type. A report (that is, a
706: constructed element of the report type) has an aggregate structure. It is
1.30 cvs 707: formed from a title, an author's name, an introduction, a body, and a
1.37 cvs 708: conclusion, making it a collection of five element types. This type of
1.30 cvs 709: constructor is found in practically every document, and generally at several
710: levels in a document.</p>
711:
712: <p>The <em>list</em> constructor is used to define constructed elements which
713: are ordered sequences of elements (constructed or primitive) having the same
714: type. The minimum and maximum numbers of elements for the sequence can be
715: specified in the list constructor or the number of elements can be left
716: unconstrained. The body of a report is a list of chapters and is typically
717: required to contain a minimum of two chapters (is a chapter useful if it is
718: the only one in the report?) The chapter itself can contain a list of
1.37 cvs 719: sections, each section containing a list of paragraphs. In the same way as
720: the aggregate, the list is a very frequently used constructor in every type
721: of document. However, these two constructors are not sufficient to describe
722: every document structure; thus other constructors supplement them.</p>
1.18 cvs 723: </div>
1.1 cvs 724:
1.18 cvs 725: <div class="subsubsection">
1.37 cvs 726: <h4><a name="sectd3132" id="sectd3132">Choice, Schema, and Unit</a></h4>
1.1 cvs 727:
1.30 cvs 728: <p>The <em>choice</em> constructor is used to define the structure of an
729: element type for which one alternative is chosen from several possibilities.
1.37 cvs 730: Thus, a paragraph can be either a simple text paragraph, or an enumeration,
731: or a citation.</p>
1.30 cvs 732:
733: <p>The choice constructor indicates the complete list of possible options,
734: which can be too restrictive in certain cases, the paragraph being one such
735: case. Two constructors, <em>unit</em> and <em>schema</em>, address this
1.37 cvs 736: inconvenience. They allow more freedom in the choice of an element type. If a
737: paragraph is defined by a schema constructor, it is possible to put in the
1.1 cvs 738: place of a paragraph a table, an equation, a drawing or any other object
1.37 cvs 739: defined by another generic logical structure. It is also possible to define a
1.1 cvs 740: paragraph as a sequence of units, which could be character strings, symbols,
1.37 cvs 741: or pictures. The choice constructor alone defines a generic logical structure
1.1 cvs 742: that is relatively constrained; in contrast, using units and schemas, a very
1.18 cvs 743: open structure can be defined.</p>
1.30 cvs 744:
745: <p>The <em>schema</em> constructor represents an object defined by a generic
1.18 cvs 746: logical structure chosen freely from among those available.</p>
1.30 cvs 747:
748: <p>The <em>unit</em> constructor represents an element whose type can be
749: either a primitive type or an element type defined as a unit in the generic
750: logical structure of the document, or in another generic logical structure
1.37 cvs 751: used in the document. Such an element may be used in document objects
1.30 cvs 752: constructed according to other generic structures.</p>
753:
754: <p>Thus, for example, if a cross-reference to a footnote is defined in the
1.37 cvs 755: generic logical structure ``Article'' as a unit, a table (an object defined
756: by another generic structure) can contain cross-references to footnotes, when
757: they appear in an article. In another type of document, a table defined by
1.1 cvs 758: the same generic structure can contain other types of elements, depending on
1.37 cvs 759: the type of document into which the table is inserted. All that is needed is
1.1 cvs 760: to declare, in the generic structure for tables, that the contents of cells
1.37 cvs 761: are units. In this way, the generic structure of objects is divided up
762: between different types of documents which are able to adapt themselves to
763: the environment into which they are inserted.</p>
1.18 cvs 764: </div>
1.1 cvs 765:
1.18 cvs 766: <div class="subsubsection">
1.37 cvs 767: <h4><a name="sectd3133" id="sectd3133">Reference and Inclusion</a></h4>
1.1 cvs 768:
1.30 cvs 769: <p>The <em>reference</em> is used to define document elements that are
1.18 cvs 770: cross-references to other elements, such as a section, a chapter, a
1.37 cvs 771: bibliographic citation, or a figure. The reference is bi-directional. It can
1.18 cvs 772: be used to access both the element being cross-referenced and each of the
773: elements which make use of the cross-reference.</p>
1.30 cvs 774:
1.37 cvs 775: <p>References can be either <em>internal</em> or <em>external</em>. That is,
1.1 cvs 776: they can designate elements which appear in the same document or in another
1.18 cvs 777: document.</p>
1.30 cvs 778:
1.37 cvs 779: <p>The <em><a name="inclusion" id="inclusion">inclusion</a></em> constructor
780: is a special type of reference. Like the reference, it is an internal or
781: external bidirectional link, but it is not a cross-reference. This link
782: represents the ``live'' inclusion of the designated element; it accesses the
783: most recent version of that element and not a ``dead'' copy, fixed in the
784: state in which it was found at the moment the copy was made. As soon as an
785: element is modified, all of its inclusions are automatically brought up to
786: date. It must be noted that, in addition to inclusion, Thot permits the
787: creation of ``dead'' copies.</p>
1.30 cvs 788:
789: <p>There are three types of inclusions: inclusions with full expansion,
1.1 cvs 790: inclusions with partial expansion, and inclusions without expansion. During
791: editing, inclusions without expansion are represented on the screen by the
792: name of the included document, in a special color, while inclusions with
1.37 cvs 793: expansion (full or partial) are represented by a copy (full or partial) of
794: the included element (also in a special color). The on-screen representation
795: of a partial inclusion is a <a href="#sectc3213">``skeleton''</a> image of
796: the included document.</p>
1.30 cvs 797:
798: <p>Inclusion with complete expansion can be used to include parts of the same
1.37 cvs 799: document or of other documents. Thus, it can be either an internal or an
800: external link. It can be used to include certain bibliographic entries of a
1.1 cvs 801: scientific article in another article, or to copy part of a mathematical
802: formula into another formula of the same document, thus assuring that both
1.18 cvs 803: copies will remain synchronized.</p>
1.30 cvs 804:
805: <p>Inclusion without expansion or with partial expansion is used to include
1.37 cvs 806: complete documents. It is always an external link. It is used primarily to
1.1 cvs 807: divide very large documents into sub-documents that are easier to manipulate,
1.37 cvs 808: especially when there are many authors. So, a book can include some chapters,
1.1 cvs 809: where each chapter is a different document which can be edited separately.
810: When viewing the book on the screen, it might be desirable to see only the
1.37 cvs 811: titles of the chapters and sections. This can be achieved using inclusion
1.18 cvs 812: with partial expansion.</p>
1.30 cvs 813:
1.37 cvs 814: <p>During printing, inclusions without expansion or with partial expansion
815: can be represented either as they were shown on the screen or by a complete
816: (and up-to-date) copy of the included element or document.</p>
1.30 cvs 817:
818: <p>The inclusion constructor, whatever its type, respects the generic
819: structure: only those elements authorized by the generic structure can be
820: included at a given position in a document.</p>
1.18 cvs 821: </div>
1.1 cvs 822:
1.18 cvs 823: <div class="subsubsection">
1.37 cvs 824: <h4><a name="sectd3134" id="sectd3134">Mark pairs</a></h4>
1.1 cvs 825:
1.30 cvs 826: <p>It is often useful to delimit certain parts of a document independently
1.37 cvs 827: from the logical structure. For example, one might wish to attach some
1.30 cvs 828: information (in the form of an <a href="#sectc315">attribute</a>) or a
829: particular treatment to a group of words or a set of consecutive paragraphs.
830: <em>Mark pairs</em> are used to do this.</p>
831:
832: <p>Mark pairs are elements which are always paired and are terminals in the
1.37 cvs 833: logical structure of the document. Their position in the structure of the
834: document is defined in the generic structure. It is important to note that
1.18 cvs 835: when the terminals of a mark pair are <em>extensions</em> (see the next
836: section), they can be used quite freely.</p>
837: </div>
1.1 cvs 838:
1.18 cvs 839: <div class="subsubsection">
1.37 cvs 840: <h4><a name="sectd3135" id="sectd3135">Restrictions and Extensions</a></h4>
1.1 cvs 841:
1.30 cvs 842: <p>The primitive types and the constructors presented so far permit the
1.1 cvs 843: definition of the logical structure of documents and objects in a rigorous
1.37 cvs 844: way. But this definition can be very cumbersome in certain cases, notably
1.1 cvs 845: when trying to constrain or extend the authorized element types in a
1.37 cvs 846: particular context. <em>Restrictions</em> and <em>extensions</em> are used to
1.18 cvs 847: cope with these cases.</p>
1.30 cvs 848:
849: <p>A restriction associates with a particular element type <em>A</em>, a list
1.37 cvs 850: of those element types which elements of type <em>A</em> may not contain,
851: even if the definition of type <em>A</em> and those of its components
852: authorize them otherwise. This simplifies the writing of generic logical
853: structures and allows limitations to be placed, when necessary, on the
854: choices offered by the schema and unit constructors.</p>
855:
856: <p>Extensions are the inverse of restrictions. They identify a list of
857: element types whose presence <em>is</em> permitted, even if its definition
858: and those of its components do not authorize them otherwise.</p>
1.18 cvs 859: </div>
860:
861: <div class="subsubsection">
1.37 cvs 862: <h4><a name="sectd3136" id="sectd3136">Summary</a></h4>
1.18 cvs 863:
1.30 cvs 864: <p>Thus, four constructors are used to construct a document:</p>
1.18 cvs 865: <ul>
1.30 cvs 866: <li>the aggregate constructor (ordered or not),</li>
867: <li>the list constructor,</li>
868: <li>the choice constructor and its extensions, the unit and schema
869: constructors,</li>
870: <li>the reference constructor and its variant, the inclusion.</li>
871: </ul>
872:
1.37 cvs 873: <p>These constructors are also sufficient for objects. Thus, these
1.30 cvs 874: constructors provide a homogenous meta-model which can describe both the
875: organization of the document as a whole and that of the various types of
1.37 cvs 876: objects which it contains. After presenting the description language for
1.30 cvs 877: generic structures, we will present several examples which illustrate the
878: appropriateness of the model.</p>
879:
1.37 cvs 880: <p>The first three constructors (aggregate, list and choice) lead to
881: tree-like structures for documents and objects, the objects being simply the
882: subtrees of the tree of a document (or even of other objects' subtrees). The
883: reference constructor introduces other, non-hierarchical, relations which
884: augment those of the tree: when a paragraph makes reference to a chapter or a
885: section, that relation leaves the purely tree-like structure. Moreover,
886: external reference and inclusion constructors permit the establishment of
887: links between different documents, thus creating a hypertext structure.</p>
1.18 cvs 888: </div>
889: </div>
1.1 cvs 890:
1.18 cvs 891: <div class="subsection">
1.37 cvs 892: <h3><a name="sectc315" id="sectc315">Attributes</a></h3>
1.1 cvs 893:
1.30 cvs 894: <p>There remain logical aspects of documents that are not entirely described
1.37 cvs 895: by the structure. Certain types of semantic information, which are not stated
896: explicitly in the text, must also be taken into account. In particular, such
1.1 cvs 897: information is shown by typographic effects which do not correspond to a
1.37 cvs 898: change between structural elements. In fact, certain titles are set in bold
1.1 cvs 899: or italic or are printed in a different typeface from the rest of the text in
1.37 cvs 900: order to mark them as structurally distinct. But these same effects
1.1 cvs 901: frequently appear in the middle of continuous text (e.g. in the interior of a
1.37 cvs 902: paragraph). In this case, there is no change between structural elements; the
903: effect serves to highlight a word, expression, or phrase. The notion of an
1.18 cvs 904: <em>attribute</em> is used to express this type of information.</p>
1.30 cvs 905:
906: <p>An attribute is a piece of information attached to a structural element
907: which augments the type of the element and clarifies its function in the
908: document. Keywords, foreign language words, and titles of other works can all
1.37 cvs 909: be represented by character strings with attached attributes. Attributes may
910: also be attached to constructed elements. Thus, an attribute indicating the
1.1 cvs 911: language can be attached to a single word or to a large part of a
1.18 cvs 912: document.</p>
1.30 cvs 913:
914: <p>In fact, an attribute can be any piece of information which is linked to a
1.37 cvs 915: part of a document and which can be used by agents which work on the
916: document. For example, the language in which the document is written
917: determines the set of characters used by an editor or formatter. It also
918: determines the algorithm or hyphenation dictionary to be used. The attribute
919: ``keyword'' facilitates the work of an information retrieval system. The
920: attribute ``index word'' allows a formatter to automatically construct an
921: index at the end of the document.</p>
1.30 cvs 922:
923: <p>As with the types of constructed elements, the attributes and the values
1.37 cvs 924: they can take are defined separately in each generic logical structure, not
925: in the meta-model, according to the needs of the document class or the nature
926: of the object.</p>
1.30 cvs 927:
928: <p>Many types of attributes are offered: numeric, textual, references, and
1.18 cvs 929: enumerations:</p>
930: <ul>
1.37 cvs 931: <li><em>Numeric attributes</em> can take integer values (negative,
932: positive, or null).</li>
1.30 cvs 933: <li><em>Textual attributes</em> have as their values character strings.</li>
934: <li><em>Reference attributes</em> designate an element of the logical
935: structure.</li>
936: <li><em>Enumeration attributes</em> can take one value from a limited list
937: of possible values, each value being a name.</li>
1.18 cvs 938: </ul>
1.30 cvs 939:
940: <p>In a generic structure, there is a distinction between <em>global
1.37 cvs 941: attributes</em> and <em>local attributes</em>. A global attribute can be
1.1 cvs 942: applied to every element type defined in the generic structure where it is
1.37 cvs 943: specified. In contrast, a local attribute can only be applied to certain
944: types of elements, even only a single type. The ``language'' attribute
945: presented above is an example of a global attribute. An example of a local
1.1 cvs 946: attribute is the rank of an author (principal author of the document or
947: secondary author): this attribute can only be applied sensibly to an element
1.18 cvs 948: of the ``author'' type.</p>
1.30 cvs 949:
950: <p>Attributes can be assigned to the elements which make up the document in
1.37 cvs 951: many different ways. The author can freely and dynamically place them on any
1.30 cvs 952: part of the document in order to attach supplementary information of his/her
1.18 cvs 953: choice. However, attributes may only be assigned in accordance with the rules
1.37 cvs 954: of the generic structure; in particular, local attributes can only be
955: assigned to those element types for which they are defined.</p>
1.30 cvs 956:
957: <p>In the generic structure, certain local attributes can be made mandatory
1.37 cvs 958: for certain element types. In this case, Thot automatically associates the
959: attribute with the elements of this type and it requires the user to provide
960: a value for this attribute.</p>
961:
962: <p>Attributes can also be automatically assigned, with a given value, by
963: every application processing the document in order to systematically add a
964: piece of information to certain predefined elements of the document. By way
965: of example, in a report containing a French abstract and an English abstract,
966: each of the two abstracts is defined as a sequence of paragraphs. The first
1.1 cvs 967: abstract has a value of ``French'' for the ``language'' attribute while the
1.18 cvs 968: second abstract's ``language'' attribute has a value of ``English''.</p>
1.30 cvs 969:
970: <p>In the case of mark pairs, attributes are logically associated with the
971: pair as a whole, but are actually attached to the first mark.</p>
1.18 cvs 972: </div>
1.1 cvs 973:
1.18 cvs 974: <div class="subsection">
1.37 cvs 975: <h3><a name="sectc316" id="sectc316">Discussion of the model</a></h3>
1.1 cvs 976:
1.37 cvs 977: <p>The notions of attribute, constructor, and structured element are used in
978: the definition of generic logical structures of documents and objects. The
979: problem is to assemble them to form generic structures. In fact, many types
980: of elements and attributes can be found in a variety of generic structures.
981: Rather than redefine them for each structure in which they appear, it is best
982: to share them between structures. The object classes already fill this
983: sharing function. If a mathematical class is defined, its formulas can be
984: used in many different document classes, without redefining the structure of
985: each class. This problem arises not only for the objects considered here; it
986: also arises for the commonplace textual elements found in many document
987: classes. This is the reason why the notion of object is so broad and why
988: paragraphs and enumerations are also considered to be objects. These object
989: classes not only permit the sharing of the structures of elements, but also
990: of the attributes defined in the generic structures.</p>
1.30 cvs 991:
992: <p>Structure, such as that presented here, can appear very rigid, and it is
1.1 cvs 993: possible to imagine that a document editing system based on this model could
1.37 cvs 994: prove very constraining to the user. This is, in fact, a common criticism of
995: syntax-directed editors. This defect can be avoided with Thot, primarily for
1.18 cvs 996: three reasons:</p>
997: <ul>
1.30 cvs 998: <li>the generic structures are not fixed in the model itself,</li>
999: <li>the model takes the dynamics of documents into account,</li>
1000: <li>the constructors offer great flexibility.</li>
1.18 cvs 1001: </ul>
1.30 cvs 1002:
1003: <p>When the generic structure of a document is not predefined, but rather is
1.1 cvs 1004: constructed specifically for each document class, it can be carefully adapted
1.37 cvs 1005: to the current needs. In cases where the generic structure is inadequate for
1.1 cvs 1006: a particular document of the class, it is always possible either to create a
1007: new class with a generic structure well suited to the new case or to extend
1.37 cvs 1008: the generic structure of the existing class to take into account the
1009: specifics of the document which poses the problem. These two solutions can
1010: also be applied to objects whose structures prove to be poorly designed.</p>
1.30 cvs 1011:
1012: <p>The model is sufficiently flexible to take into account all the phases of
1.37 cvs 1013: the life of the document. When a generic structure specifies that a report
1014: must contain a title, an abstract, an introduction, at least two chapters,
1015: and a conclusion, this means only that a report, <em>upon completion</em>,
1016: will have to contain all of these elements. When the author begins writing,
1017: none of these elements is present. Thot uses this model. Therefore, it
1018: tolerates documents which do not conform strictly to the generic structure of
1019: their class; it also considers the generic logical structure to be a way of
1020: helping the user in the construction of a complex document.</p>
1.30 cvs 1021:
1022: <p>In contrast, other applications may reject a document which does not
1.37 cvs 1023: conform strictly to its generic structure. This is, for example, what is done
1.30 cvs 1024: by compilers which refuse to generate code for a program which is not
1.37 cvs 1025: syntactically correct. This might also occur when using a document
1.18 cvs 1026: application for a report which does not have an abstract or title.</p>
1.30 cvs 1027:
1028: <p>The constructors of the document model bring a great flexibility to the
1.37 cvs 1029: generic structures. A choice constructor (and even more, a unit or schema
1030: constructor) can represent several, very different elements. The list
1031: constructor permits the addition of more elements of the same type. Used
1.1 cvs 1032: together, these two constructors permit any series of elements of different
1.37 cvs 1033: types. Of course, this flexibility can be reduced wherever necessary since a
1.1 cvs 1034: generic structure can limit the choices or the number of elements in a
1.18 cvs 1035: list.</p>
1.30 cvs 1036:
1037: <p>Another difficulty linked to the use of structure in the document model
1.37 cvs 1038: resides in the choice of the level of the structure. The structure of a
1.1 cvs 1039: discussion could be extracted from the text itself via linguistic analysis.
1040: Some studies are exploring this approach, but the model of Thot excludes this
1.37 cvs 1041: type of structure. It only takes into account the logical structure provided
1.18 cvs 1042: explicitly by the author.</p>
1.30 cvs 1043:
1.37 cvs 1044: <p>However, the level of structure of the model is not imposed. Each generic
1045: structure defines its own level of structure, adapted to the document class
1046: or object and to the ways in which it will be processed. If it will only be
1047: edited and printed, a relatively simple structure suffices. If more
1048: specialized processing will be applied to it, the structure must represent
1049: the element types on which this processing must act. By way of example, a
1050: simple structure is sufficient for printing formulas, but a more complex
1051: structure is required to perform symbolic or numeric calculations on the
1052: mathematical expressions. The document model of Thot allows both types of
1053: structure.</p>
1.18 cvs 1054: </div>
1055: </div>
1.1 cvs 1056:
1.18 cvs 1057: <div class="section">
1.37 cvs 1058: <h2><a name="sectb32" id="sectb32">The definition language for generic
1059: structures</a></h2>
1.1 cvs 1060:
1.37 cvs 1061: <p>Generic structures, which form the basis of the document model of Thot,
1062: are specified using a special language. This definition language, called S,
1063: is described in this section.</p>
1.30 cvs 1064:
1065: <p>Each generic structure, which defines a class of documents or objects, is
1.2 cvs 1066: specified by a file, written in the S language, which is called a
1.37 cvs 1067: <em>structure schema</em>. Structure schemas are compiled into tables, called
1.18 cvs 1068: structure tables, which are used by Thot and which determine its behavior.</p>
1.1 cvs 1069:
1.18 cvs 1070: <div class="subsection">
1.37 cvs 1071: <h3><a name="sectc321" id="sectc321">Writing Conventions</a></h3>
1.1 cvs 1072:
1.30 cvs 1073: <p>The grammar of S, like those of the languages P and T presented later, is
1.1 cvs 1074: described using the meta-language M, derived from the Backus-Naur Form
1.18 cvs 1075: (BNF).</p>
1.30 cvs 1076:
1077: <p>In this meta-language each rule of the grammar is composed of a grammar
1.37 cvs 1078: symbol followed by an equals sign (`=') and the right part of the rule. The
1.30 cvs 1079: equals sign plays the same role as the traditional `::=' of BNF: it indicates
1.37 cvs 1080: that the right part defines the symbol of the left part. In the right
1.30 cvs 1081: part,</p>
1.18 cvs 1082: <dl>
1.30 cvs 1083: <dt>concatenation</dt>
1084: <dd>is shown by the juxtaposition of symbols;</dd>
1085: <dt>character strings</dt>
1.37 cvs 1086: <dd>between apostrophes ' represent terminal symbols, that is, keywords
1087: in the language defined. Keywords are written here in upper-case
1088: letters, but can be written in any combination of upper and lower-case
1089: letters. For example, the keyword <tt>DEFPRES</tt> of S can also be
1090: written as <tt>defpres</tt> or <tt>DefPres</tt>.</dd>
1.30 cvs 1091: <dt>material between brackets</dt>
1092: <dd>(`[' and `]') is optional;</dd>
1093: <dt>material between angle brackets</dt>
1094: <dd>(`<' and `>') can be repeated many times or omitted;</dd>
1095: <dt>the slash</dt>
1.37 cvs 1096: <dd>(`/') indicates an alternative, a choice between the options
1097: separated by the slash character;</dd>
1.30 cvs 1098: <dt>the period</dt>
1099: <dd>marks the end of a rule;</dd>
1100: <dt>text between braces</dt>
1101: <dd>(`{' and `}') is simply a comment.</dd>
1.18 cvs 1102: </dl>
1.30 cvs 1103:
1104: <p>The M meta-language also uses the concepts of identifiers, strings, and
1.18 cvs 1105: integers:</p>
1106: <dl>
1.30 cvs 1107: <dt><tt>NAME</tt></dt>
1.37 cvs 1108: <dd>represents an identifier, a sequence of letters (upper or
1109: lower-case), digits, and underline characters (`_'), beginning with a
1110: letter. Also considered a letter is the sequence of characters
1111: `<tt>\nnn</tt>' where the letter <tt>n</tt> represents the ISO Latin-1
1112: code of the letter in octal. It is thus possible to use accented
1113: letters in identifiers. The maximum length of identifiers is fixed by
1114: the compiler. It is normally 31 characters.
1.30 cvs 1115: <p>Unlike keywords, upper and lower-case letters are distinct in
1116: identifiers. Thus, <tt>Title</tt>, <tt>TITLE</tt>, and <tt>title</tt>
1117: are considered different identifiers.</p>
1118: </dd>
1119: <dt><tt>STRING</tt></dt>
1.37 cvs 1120: <dd>represents a string. This is a string of characters delimited by
1121: apostrophes. If an apostrophe must appear in a string, it is doubled.
1122: As with identifiers, strings can contain characters represented by
1123: their octal code (after a backslash). As with apostrophes, if a
1124: backslash must appear in a string, it is doubled.</dd>
1.30 cvs 1125: <dt><tt>NUMBER</tt></dt>
1126: <dd>represents a positive integer or zero (without a sign), or said
1127: another way, a sequence of decimal digits.</dd>
1.18 cvs 1128: </dl>
1.30 cvs 1129:
1130: <p>The M language can be used to define itself as follows:</p>
1.18 cvs 1131: <pre>{ Any text between braces is a comment. }
1.30 cvs 1132: Grammar = Rule < Rule > 'END' .
1133: { The < and > signs indicate zero }
1.1 cvs 1134: { or more repetitions. }
1135: { END marks the end of the grammar. }
1136: Rule = Ident '=' RightPart '.' .
1137: { The period indicates the end of a rule }
1138: RightPart = RtTerminal / RtIntermed .
1139: { The slash indicates a choice }
1140: RtTerminal ='NAME' / 'STRING' / 'NUMBER' .
1141: { Right part of a terminal rule }
1.30 cvs 1142: RtIntermed = Possibility < '/' Possibility > .
1.1 cvs 1143: { Right part of an intermediate rule }
1.30 cvs 1144: Possibility = ElemOpt < ElemOpt > .
1145: ElemOpt = Element / '[' Element < Element > ']' /
1146: '<' Element < Element > '>' .
1.1 cvs 1147: { Brackets delimit optional parts }
1148: Element = Ident / KeyWord .
1149: Ident = NAME .
1150: { Identifier, sequence of characters }
1151: KeyWord = STRING .
1152: { Character string delimited by apostrophes }
1.18 cvs 1153: END</pre>
1154: </div>
1.1 cvs 1155:
1.18 cvs 1156: <div class="subsection">
1.37 cvs 1157: <h3><a name="sectc322" id="sectc322">Extension schemas</a></h3>
1.1 cvs 1158:
1.30 cvs 1159: <p>A structure schema defines the generic logical structure of a class of
1.1 cvs 1160: documents or objects, independent of the operations which can be performed on
1.37 cvs 1161: the documents. However, certain applications may require particular
1.1 cvs 1162: information to be represented by the structure for the documents that they
1.37 cvs 1163: operate on. Thus a document version manager will need to indicate in the
1164: document the parts which belong to one version or another. An indexing system
1.1 cvs 1165: will add highly-structured index tables as well as the links between these
1.18 cvs 1166: tables and the rest of the document.</p>
1.30 cvs 1167:
1168: <p>Thus, many applications need to extend the generic structure of the
1.37 cvs 1169: documents on which they operate to introduce new attributes or element types.
1170: These additions are specific to each application and must be able to be
1171: applied to any generic structure: users will want to manage versions or
1172: construct indices for many types of documents. Extension schemas fulfill this
1173: role: they define attributes, elements, units, etc., but they can only be
1174: used jointly with a structure schema that they complete. Otherwise, structure
1175: schemas can always be used without these extensions when the corresponding
1176: applications are not available.</p>
1.18 cvs 1177: </div>
1.1 cvs 1178:
1.18 cvs 1179: <div class="subsection">
1.37 cvs 1180: <h3><a name="sectc323" id="sectc323">The general organization of structure
1181: schemas</a></h3>
1.1 cvs 1182:
1.30 cvs 1183: <p>Every structure schema begins with the keyword <tt>STRUCTURE</tt> and ends
1.37 cvs 1184: with the keyword <tt>END</tt>. The keyword <tt>STRUCTURE</tt> is followed by
1.18 cvs 1185: the keyword <tt>EXTENSION</tt> in the case where the schema defines an
1.1 cvs 1186: extension, then by the name of the generic structure which the schema defines
1.37 cvs 1187: (the name of the document or object class). The name of the structure is
1.18 cvs 1188: followed by a semicolon.</p>
1.30 cvs 1189:
1190: <p>In the case of a complete schema (that is, a schema which is not an
1.1 cvs 1191: extension), the definition of the name of the structure is followed by the
1192: declarations of the default presentation schema, the global attributes, the
1.37 cvs 1193: structure rules, the units, the skeleton elements and the exceptions. Only
1194: the definition of the structure rules is required. Each series of
1195: declarations begins with a keyword: <tt>DEFPRES</tt>, <tt>ATTR</tt>,
1196: <tt>STRUCT</tt>, <tt>UNITS</tt>, <tt>EXPORT</tt>, <tt>EXCEPT</tt>.</p>
1.34 cvs 1197:
1198: <p>In the case of an extension schema, there are no skeleton elements and the
1199: <tt>STRUCT</tt> section is optional, while that section is required in a
1.37 cvs 1200: schema that is not an extension. On the other hand, extension schemas can
1201: contain an <tt>EXTENS</tt> section, which must not appear in a schema which
1202: is not an extension; this section defines the complements to attach to the
1203: rules found in the schema to which the extension will be added. The sections
1204: <tt>ATTR</tt>, <tt>STRUCT</tt>, and <tt>UNITS</tt> define new attributes, new
1205: elements, and new units which add their definitions to the principal
1206: schema.</p>
1.18 cvs 1207: <pre> StructSchema ='STRUCTURE' ElemID ';'
1.1 cvs 1208: 'DEFPRES' PresID ';'
1209: [ 'ATTR' AttrSeq ]
1210: 'STRUCT' RulesSeq
1211: [ 'UNITS' RulesSeq ]
1212: [ 'EXPORT' SkeletonSeq ]
1213: [ 'EXCEPT' ExceptSeq ]
1214: 'END' .
1.18 cvs 1215: ElemID = NAME .</pre>
1.30 cvs 1216:
1217: <p>or</p>
1.18 cvs 1218: <pre> ExtensSchema ='STRUCTURE' 'EXTENSION' ElemID ';'
1.1 cvs 1219: 'DEFPRES' PresID ';'
1220: [ 'ATTR' AttrSeq ]
1221: [ 'STRUCT' RulesSeq ]
1222: [ 'EXTENS' ExtensRuleSeq ]
1223: [ 'UNITS' RulesSeq ]
1224: [ 'EXCEPT' ExceptSeq ]
1225: 'END' .
1.18 cvs 1226: ElemID = NAME .</pre>
1227: </div>
1.1 cvs 1228:
1.18 cvs 1229: <div class="subsection">
1.37 cvs 1230: <h3><a name="sectc324" id="sectc324">The default presentation</a></h3>
1.1 cvs 1231:
1.37 cvs 1232: <p>It was shown <a href="#mulpres">above</a> that many different
1233: presentations are possible for documents and objects of the same class. The
1234: structure schema defines a preferred presentation for the class, called the
1235: <em>default presentation</em>. Like generic structures, presentations are
1236: described by programs, called <em>presentation schemas</em>, which are
1237: written in a specific language, P, presented <a href="#sectb42">later</a> in
1238: this document. The name appearing after the keyword <tt>DEFPRES</tt> is the
1239: name of the default presentation schema. When a new document is created, Thot
1240: will use this presentation schema by default, but the user remains free to
1241: choose another if s/he wishes.</p>
1.18 cvs 1242: <pre> PresID = NAME .</pre>
1243: </div>
1.1 cvs 1244:
1.18 cvs 1245: <div class="subsection">
1.37 cvs 1246: <h3><a name="sectc325" id="sectc325">Global Attributes</a></h3>
1.1 cvs 1247:
1.30 cvs 1248: <p>If the generic structure includes global attributes of its own, they are
1.37 cvs 1249: declared after the keyword <tt>ATTR</tt>. Each global attribute is defined by
1250: its name, followed by an equals sign and the definition of its type. The
1.18 cvs 1251: declaration of a global attribute is terminated by a semi-colon.</p>
1.30 cvs 1252:
1253: <p>For attributes of the numeric, textual, or reference types, the type is
1.37 cvs 1254: indicated by a keyword, <tt>INTEGER</tt>, <tt>TEXT</tt>, or
1255: <tt>REFERENCE</tt> respectively.</p>
1.30 cvs 1256:
1257: <p>In the case of a reference attribute, the keyword <tt>REFERENCE</tt> is
1.37 cvs 1258: followed by the type of the referenced element in parentheses. It can refer
1.18 cvs 1259: to any type at all, specified by using the keyword <tt>ANY</tt>, or to a
1.37 cvs 1260: specific type. In the latter case, the element type designated by the
1.18 cvs 1261: reference can be defined either in the <a href="#sectc327"><tt>STRUCT</tt>
1262: section</a> of the same structure schema or in the <tt>STRUCT</tt> section of
1.37 cvs 1263: another structure schema. When the type is defined in another schema, the
1.1 cvs 1264: element type is followed by the name of the structure schema (within
1.37 cvs 1265: parentheses) in which it is defined. The name of the designated element type
1.18 cvs 1266: can be preceded by the keyword <tt>First</tt> or <tt>Second</tt>, but only in
1.37 cvs 1267: the case where the type is defined as <a href="#sectd3285">a pair</a>. These
1.1 cvs 1268: keywords indicate whether the attribute must designate the first mark of the
1.37 cvs 1269: pair or the second. If the reference refers to a pair and neither of these
1.18 cvs 1270: two keywords is present, then the first mark is used.</p>
1.30 cvs 1271:
1.37 cvs 1272: <p>In the case of an enumeration attribute, the equals sign is followed by
1273: the list of names representing the possible values of the attribute, the
1274: names being separated from each other by commas. An enumeration attribute has
1275: at least one possible value; the maximum number of values is defined by the
1.18 cvs 1276: compiler for the S language.</p>
1.30 cvs 1277: <pre> AttrSeq = Attribute < Attribute > .
1.1 cvs 1278: Attribute = AttrID '=' AttrType ';' .
1279: AttrType = 'INTEGER' / 'TEXT' /
1280: 'REFERENCE' '(' RefType ')' /
1281: ValueSeq .
1282: RefType = 'ANY' / [ FirstSec ] ElemID [ ExtStruct ] .
1283: FirstSec = 'First' / 'Second' .
1284: ExtStruct = '(' ElemID ')' .
1.30 cvs 1285: ValueSeq = AttrVal < ',' AttrVal > .
1.1 cvs 1286: AttrID = NAME .
1.18 cvs 1287: AttrVal = NAME .</pre>
1.30 cvs 1288:
1289: <p>There is a predefined global text attribute, the <em>language</em>, which
1.37 cvs 1290: is automatically added to every Thot structure schema. This attribute allows
1291: Thot to perform certain actions, such as hyphenation and spell-checking,
1292: which cannot be performed without knowing the language in which each part of
1293: the document is written. This attribute can be used just like any explicitly
1.18 cvs 1294: declared attribute: the system acts as if every structure schema contains</p>
1295: <pre>ATTR
1296: Language = TEXT;</pre>
1.30 cvs 1297:
1.18 cvs 1298: <blockquote class="example">
1.30 cvs 1299: <p><strong>Example:</strong></p>
1300:
1301: <p>The following specification defines the global enumeration attribute
1302: WordType.</p>
1303: <pre>ATTR
1.18 cvs 1304: WordType = Definition, IndexWord, DocumentTitle;</pre>
1305: </blockquote>
1306: </div>
1.1 cvs 1307:
1.18 cvs 1308: <div class="subsection">
1.37 cvs 1309: <h3><a name="sectc327" id="sectc327">Structured elements</a></h3>
1.1 cvs 1310:
1.30 cvs 1311: <p>The rules for defining structured elements are required, except in an
1.1 cvs 1312: extension schema: they constitute the core of a structure schema, since they
1313: define the structure of the different types of elements that occur in a
1.18 cvs 1314: document or object of the class defined by the schema.</p>
1.30 cvs 1315:
1316: <p>The first structure rule after the keyword <tt>STRUCT</tt> must define the
1.1 cvs 1317: structure of the class whose name appears in the first instruction
1.37 cvs 1318: (<tt>STRUCTURE</tt>) of the schema. This is the root rule of the schema,
1.18 cvs 1319: defining the root of the document tree or object tree.</p>
1.30 cvs 1320:
1321: <p>The remaining rules may be placed in any order, since the language permits
1.37 cvs 1322: the definition of element types before or after their use, or even in the
1323: same instruction in which they are used. This last case allows the definition
1324: of recursive structures.</p>
1.30 cvs 1325:
1326: <p>Each rule is composed of a name (the name of the element type whose
1327: structure is being defined) followed by an equals sign and a structure
1328: definition.</p>
1329:
1.37 cvs 1330: <p>If any local attributes are associated with the element type defined by
1331: the rule, they appear between parentheses after the type name and before the
1332: equals sign. The parentheses contain, first, the keyword <tt>ATTR</tt>, then
1333: the list of local attributes, separated by commas. Each local attribute is
1.2 cvs 1334: composed of the name of the attribute followed by an equals sign and the
1.18 cvs 1335: definition of the attribute's type, just as in the definition of <a
1.37 cvs 1336: href="#sectc325">global attributes</a>. The name of the attribute can be
1337: preceded by an exclamation point to indicate that the attribute must always
1338: be present for this element type. The same attribute, identified by its name,
1339: can be defined as a local attribute for multiple element types. In this case,
1340: the equals sign and definition of the attribute type need only appear in the
1341: first occurrence of the attribute. It should be noted that global attributes
1342: cannot also be defined as local attributes.</p>
1.30 cvs 1343:
1344: <p>If any <a href="#sectd3135">extensions</a> are defined for this element
1345: type, a plus sign follows the structure definition and the names of the
1.37 cvs 1346: extension element types appear between parentheses after the plus. If there
1347: are multiple extensions, they are separated by commas. These types can either
1.30 cvs 1348: be defined in the same schema, defined in other schemas, or they may be base
1.18 cvs 1349: types identified by the keywords <tt>TEXT</tt>, <tt>GRAPHICS</tt>,
1350: <tt>SYMBOL</tt>, or <tt>PICTURE</tt>.</p>
1.30 cvs 1351:
1352: <p><a href="#sectd3135">Restrictions</a> are indicated in the same manner as
1.18 cvs 1353: extensions, but they are introduced by a minus sign and they come after the
1354: extensions, or if there are no extensions, after the structure definition.</p>
1.30 cvs 1355:
1.37 cvs 1356: <p>If the values of attributes must be attached systematically to this
1357: element type, they are introduced by the keyword <tt>WITH</tt> and declared
1358: in the form of a list of fixed-value attributes. When such definitions of
1359: fixed attribute values appear, they are always the last part of the rule.</p>
1.30 cvs 1360:
1361: <p>The rule is terminated by a semicolon.</p>
1362: <pre> RuleSeq = Rule < Rule > .
1.1 cvs 1363: Rule = ElemID [ LocAttrSeq ] '=' DefWithAttr ';'.
1.30 cvs 1364: LocAttrSeq = '(' 'ATTR' LocAttr < ';' LocAttr > ')' .
1.1 cvs 1365: LocAttr = [ '!' ] AttrID [ '=' AttrType ] .
1366: DefWithAttr = Definition
1367: [ '+' '(' ExtensionSeq ')' ]
1368: [ '-' '(' RestrictSeq ')' ]
1369: [ 'WITH' FixedAttrSeq ] .
1.30 cvs 1370: ExtensionSeq = ExtensionElem < ',' ExtensionElem > .
1.1 cvs 1371: ExtensionElem = ElemID / 'TEXT' / 'GRAPHICS' /
1372: 'SYMBOL' / 'PICTURE' .
1.30 cvs 1373: RestrictSeq = RestrictElem < ',' RestrictElem > .
1.1 cvs 1374: RestrictElem = ElemID / 'TEXT' / 'GRAPHICS' /
1.18 cvs 1375: 'SYMBOL' / 'PICTURE' .</pre>
1.30 cvs 1376:
1377: <p>The list of fixed-value attributes is composed of a sequence of
1.37 cvs 1378: attribute-value pairs separated by commas. Each pair contains the name of the
1.1 cvs 1379: attribute and the fixed value for this element type, the two being separated
1.37 cvs 1380: by an equals sign. If the sign is preceded by a question mark the given value
1.1 cvs 1381: is only an initial value that may be modified later rather than a value fixed
1.37 cvs 1382: for all time. Reference attributes are an exception to this norm. They cannot
1383: be assigned a fixed value, but when the name of such an attribute appears
1384: this indicates that this element type must have a valid value for the
1385: attribute. For the other attribute types, the fixed value is indicated by a
1.1 cvs 1386: signed integer (numeric attributes), a character string between apostrophes
1.18 cvs 1387: (textual attributes) or the name of a value (enumeration attributes).</p>
1.30 cvs 1388:
1389: <p>Fixed-value attributes can either be <a href="#sectc325">global</a> or
1390: local to the element type for which they are fixed, but they must be declared
1391: before they are used.</p>
1392: <pre> FixedAttrSeq = FixedAttr < ',' FixedAttr > .
1.1 cvs 1393: FixedAttr = AttrID [ FixedOrModifVal ] .
1394: FixedOrModifVal = [ '?' ] '=' FixedValue .
1395: FixedValue = [ '-' ] NumValue / TextVal / AttrVal .
1396: NumValue = NUMBER .
1.18 cvs 1397: TextVal = STRING .</pre>
1398: </div>
1.1 cvs 1399:
1.18 cvs 1400: <div class="subsection">
1.37 cvs 1401: <h3><a name="sectc328" id="sectc328">Structure definitions</a></h3>
1.1 cvs 1402:
1.37 cvs 1403: <p>The structure of an element type can be a simple base type or a
1404: constructed type.</p>
1.30 cvs 1405:
1406: <p>For constructed types, it is frequently the case that similar structures
1.37 cvs 1407: appear in many places in a document. For example the contents of the
1.1 cvs 1408: abstract, of the introduction, and of a section can have the same structure,
1.37 cvs 1409: that of a sequence of paragraphs. In this case, a single, common structure
1.1 cvs 1410: can be defined (the paragraph sequence in this example), and the schema is
1411: written to indicate that each element type possesses this structure, as
1.18 cvs 1412: follows:</p>
1413: <pre> Abstract = Paragraph_sequence;
1.1 cvs 1414: Introduction = Paragraph_sequence;
1.18 cvs 1415: Section_contents = Paragraph_sequence;</pre>
1.30 cvs 1416:
1417: <p>The equals sign means ``has the same structure as''.</p>
1418:
1.37 cvs 1419: <p>If the element type defined is a simple base type, this is indicated by
1420: one of the keywords <tt>TEXT</tt>, <tt>GRAPHICS</tt>, <tt>SYMBOL</tt>, or
1421: <tt>PICTURE</tt>. If some local attributes must be associated with a base
1422: type, the keyword of the base type is followed by the declaration of the
1423: local attributes using the syntax <a href="#sectc327">presented above.</a></p>
1.30 cvs 1424:
1425: <p>In the case of an open choice, the type is indicated by the keyword
1.18 cvs 1426: <tt>UNIT</tt> for units or the keyword <tt>NATURE</tt> for objects having a
1427: structure defined by any other schema.</p>
1.30 cvs 1428:
1429: <p>A unit represents one of the two following categories:</p>
1.18 cvs 1430: <ul>
1.30 cvs 1431: <li>a base type: text, graphical element, symbol, picture,</li>
1.37 cvs 1432: <li>an element whose type is chosen from among the types defined as units
1433: in the <tt>UNITS</tt> section of the document's structure schema. It can
1.30 cvs 1434: also be chosen from among the types defined as <a
1435: href="#sectd3132">units</a> in the <a href="#sectc3212"><tt>UNITS</tt>
1436: section</a> of the structure schemas that defines the ancestors of the
1437: element to which the rule is applied.</li>
1.18 cvs 1438: </ul>
1.30 cvs 1439:
1440: <p>Before the creation of an element defined as a unit, Thot asks the user to
1.18 cvs 1441: choose between the categories of elements.</p>
1.30 cvs 1442:
1443: <p>Thus, the contents of a paragraph can be specified as a sequence of units,
1.1 cvs 1444: which will permit the inclusion in the paragraphs of character strings,
1445: symbols, and various elements, such as cross-references, if these are defined
1.18 cvs 1446: as units.</p>
1.30 cvs 1447:
1.37 cvs 1448: <p>A schema object (keyword <tt>NATURE</tt>) represents an object defined by
1449: a structure schema freely chosen from among the available schemas; in the
1450: case the element type is defined by the first rule (the root rule) of the
1451: chosen schema.</p>
1.30 cvs 1452:
1453: <p>If the element type defined is a constructed type, the list, aggregate,
1.37 cvs 1454: choice, and reference constructors are used. In this case the definition
1455: begins with a keyword identifying the constructor. This keyword is followed
1.18 cvs 1456: by a syntax specific to each constructor.</p>
1.30 cvs 1457:
1458: <p>The local attribute definitions appear after the name of the element type
1.18 cvs 1459: being defined, if this element type has <a href="#sectc327">local
1460: attributes</a>.</p>
1461: <pre> Definition = BaseType [ LocAttrSeq ] / Constr / Element .
1.1 cvs 1462: BaseType = 'TEXT' / 'GRAPHICS' / 'SYMBOL' / 'PICTURE' /
1463: 'UNIT' / 'NATURE' .
1464: Element = ElemID [ ExtOrDef ] .
1465: ExtOrDef = 'EXTERN' / 'INCLUDED' /
1466: [ LocAttrSeq ] '=' Definition .
1467: Constr = 'LIST' [ '[' min '..' max ']' ] 'OF'
1468: '(' DefWithAttr ')' /
1469: 'BEGIN' DefOptSeq 'END' /
1470: 'AGGREGATE' DefOptSeq 'END' /
1471: 'CASE' 'OF' DefSeq 'END' /
1472: 'REFERENCE' '(' RefType ')' /
1.18 cvs 1473: 'PAIR' .</pre>
1.1 cvs 1474:
1.18 cvs 1475: <div class="subsubsection">
1.37 cvs 1476: <h4><a name="sectd3281" id="sectd3281">List</a></h4>
1.1 cvs 1477:
1.30 cvs 1478: <p>The list constructor permits the definition of an element type composed of
1.37 cvs 1479: a list of elements, all of the same type. A list definition begins with the
1.18 cvs 1480: <tt>LIST</tt> keyword followed by an optional range, the keyword <tt>OF</tt>,
1.1 cvs 1481: and the definition, between parentheses, of the element type which must
1.37 cvs 1482: compose the list. The optional range is composed of the minimum and maximum
1.1 cvs 1483: number of elements for the list separated by two periods and enclosed by
1.37 cvs 1484: brackets. If the range is not present, the number of list elements is
1485: unconstrained. When only one of the two bounds of the range is unconstrained,
1486: it is represented by a star ('*') character. Even when both bounds are
1487: unconstrained, they can be specified by <tt>[*..*]</tt>, but it is simpler
1488: not to specify any bound.</p>
1.18 cvs 1489: <pre> 'LIST' [ '[' min '..' max ']' ]
1.1 cvs 1490: 'OF' '(' DefWithAttr ')'
1491: min = Integer / '*' .
1492: max = Integer / '*' .
1.18 cvs 1493: Integer = NUMBER .</pre>
1.30 cvs 1494:
1495: <p>Before the document is edited, Thot creates the minimum number of elements
1.37 cvs 1496: for the list. If no minimum was given, it creates a single element. If a
1.30 cvs 1497: maximum number of elements is given and that number is attained, the editor
1498: refuses to create new elements for the list.</p>
1499:
1500: <blockquote class="example">
1501: <p><strong>Example:</strong></p>
1502:
1503: <p>The following two instructions define the body of a document as a
1504: sequence of at least two chapters and the contents of a section as a
1.37 cvs 1505: sequence of paragraphs. A single paragraph can be the entire contents of a
1.30 cvs 1506: section.</p>
1507: <pre>Body = LIST [2..*] OF (Chapter);
1.18 cvs 1508: Section_contents = LIST OF (Paragraph);</pre>
1509: </blockquote>
1510: </div>
1.1 cvs 1511:
1.18 cvs 1512: <div class="subsubsection">
1.37 cvs 1513: <h4><a name="sectd3282" id="sectd3282">Aggregate</a></h4>
1.1 cvs 1514:
1.37 cvs 1515: <p>The aggregate constructor is used to define an element type as a
1516: collection of sub-elements, each having a fixed type. The collection may be
1517: ordered or unordered. The elements composing the collection are called
1518: <em>components</em>. In the definition of an aggregate, a keyword indicates
1.18 cvs 1519: whether or not the aggregate is ordered: <tt>BEGIN</tt> for an ordered
1520: aggregate, <tt>AGGREGATE</tt> for an unordered aggregate. This keyword is
1.1 cvs 1521: followed by the list of component type definitions which is terminated by the
1.37 cvs 1522: <tt>END</tt> keyword. The component type definitions are separated by
1.18 cvs 1523: commas.</p>
1.30 cvs 1524:
1525: <p>Before creating an aggregate, the Thot editor creates all the aggregate's
1.1 cvs 1526: components in the order they appear in the structure schema, even for
1.37 cvs 1527: unordered aggregates. However, unlike ordered aggregates, the components of
1.1 cvs 1528: an unordered aggregate may be rearranged using operations of the Thot editor.
1529: The exceptions to the rule are any components whose name was preceded by a
1.37 cvs 1530: question mark character ('?'). These components, which are optional, can be
1.1 cvs 1531: created by explicit request, possibly at the time the aggregate is created,
1.18 cvs 1532: but they are not created automatically <em>prior</em> to the creation of the
1533: aggregate.</p>
1534: <pre> 'BEGIN' DefOptSeq 'END'
1.30 cvs 1535: DefOptSeq = DefOpt ';' < DefOpt ';' > .
1.18 cvs 1536: DefOpt = [ '?' ] DefWithAttr .</pre>
1.30 cvs 1537:
1.18 cvs 1538: <blockquote class="example">
1.30 cvs 1539: <p><strong>Example:</strong></p>
1540:
1541: <p>In a bilingual document, each paragraph has an English version and a
1.37 cvs 1542: French version. In certain cases, the translator wants to add a marginal
1543: note, but this note is present in very few paragraphs. Thus, it must not be
1544: created systematically for every paragraph. A bilingual paragraph of this
1.30 cvs 1545: type is declared:</p>
1546: <pre>Bilingual_paragraph = BEGIN
1.1 cvs 1547: French_paragraph = TEXT;
1548: English_paragraph = TEXT;
1549: ? Note = TEXT;
1.18 cvs 1550: END;</pre>
1551: </blockquote>
1552: </div>
1.1 cvs 1553:
1.18 cvs 1554: <div class="subsubsection">
1.37 cvs 1555: <h4><a name="sectd3283" id="sectd3283">Choice</a></h4>
1.1 cvs 1556:
1.30 cvs 1557: <p>The choice constructor permits the definition of an element type which is
1.37 cvs 1558: chosen from among a set of possible types. The keywords <tt>CASE</tt> and
1559: <tt>OF</tt> are followed by a list of definitions of possible types, which
1560: are separated by semicolons and terminated by the <tt>END</tt> keyword.</p>
1.18 cvs 1561: <pre> 'CASE' 'OF' DefSeq 'END'
1.30 cvs 1562: DefSeq = DefWithAttr ';' < DefWithAttr ';' > .</pre>
1563:
1564: <p>Before the creation of an element defined as a choice, the Thot editor
1.37 cvs 1565: presents the list of possible types for the element to the user. The user has
1.18 cvs 1566: only to select the element type that s/he wants to create from this list.</p>
1.30 cvs 1567:
1.37 cvs 1568: <p>The order of the type declarations is important. It determines the order
1569: of the list presented to the user before the creation of the element. Also,
1.30 cvs 1570: when a Choice element is being created automatically, the first type in the
1.37 cvs 1571: list is used. In fact, using the Thot editor, when an empty Choice element is
1.1 cvs 1572: selected, it is possible to select this element and to enter its text from
1573: keyboard. In this case, the editor uses the first element type which can
1.18 cvs 1574: contain an atom of the character string type.</p>
1.30 cvs 1575:
1576: <p>The two special cases of the choice constructor, the <a
1.18 cvs 1577: href="#sectc328"><em>schema</em></a> and the <a
1578: href="#sectc3212"><em>unit</em></a> are discussed elsewhere.</p>
1.30 cvs 1579:
1.18 cvs 1580: <blockquote class="example">
1.30 cvs 1581: <p><strong>Example:</strong></p>
1582:
1583: <p>It is common in documents to treat a variety of objects as if they were
1.37 cvs 1584: ordinary paragraphs. Thus, a ``Paragraph'' might actually be composed of a
1.30 cvs 1585: block of text (an ordinary paragraph), or a mathematical formula whose
1586: structure is defined by another structure schema named Math, or a table,
1.37 cvs 1587: also defined by another structure schema. Here is a definition of such a
1.30 cvs 1588: paragraph:</p>
1589: <pre>Paragraph = CASE OF
1.1 cvs 1590: Simple_text = TEXT;
1591: Formula = Math;
1592: Table_para = Table;
1.18 cvs 1593: END;</pre>
1594: </blockquote>
1595: </div>
1.1 cvs 1596:
1.18 cvs 1597: <div class="subsubsection">
1.37 cvs 1598: <h4><a name="sectd3284" id="sectd3284">Reference</a></h4>
1.1 cvs 1599:
1.37 cvs 1600: <p>Like all elements in Thot, references are typed. An element type defined
1.30 cvs 1601: as a reference is a cross-reference to an element of some other given type.
1602: The keyword <tt>REFERENCE</tt> is followed by the name of a type enclosed in
1.37 cvs 1603: parentheses. When the type which is being cross-referenced is defined in
1.1 cvs 1604: another structure schema, the type name is itself followed by the name of the
1.18 cvs 1605: external structure schema in which it is defined.</p>
1.30 cvs 1606:
1607: <p>When the designated element type is a <a href="#sectd3285">mark pair</a>,
1.37 cvs 1608: it can be preceded by a <tt>FIRST</tt> or <tt>SECOND</tt> keyword. These
1.18 cvs 1609: keywords indicate whether the reference points to the first or second mark of
1610: the pair. If the reference points to a pair and neither of these two keywords
1611: is present, the reference is considered to point to the first mark of the
1612: pair.</p>
1.30 cvs 1613:
1.37 cvs 1614: <p>There is an exception to the principle of typed references: it is possible
1.30 cvs 1615: to define a reference which designates an element of any type, which can
1616: either be in the same document or another document. In this case, it suffices
1617: to put the keyword <tt>ANY</tt> in the parentheses which indicate the
1618: referenced element type.</p>
1.18 cvs 1619: <pre> 'REFERENCE' '(' RefType ')'
1620: RefType = 'ANY' / [ FirstSec ] ElemID [ ExtStruct ] .</pre>
1.30 cvs 1621:
1622: <p>When defining an inclusion, the <tt>REFERENCE</tt> keyword is not used.
1.1 cvs 1623: Inclusions with complete expansion are not declared as such in the structure
1.37 cvs 1624: schemas, since any element defined in a structure schema can be replaced by
1625: an element of the same type. Instead, inclusions without expansion or with
1.1 cvs 1626: partial expansion must be declared explicitly whenever they will include a
1.37 cvs 1627: complete object ( and not a part of an object). In this case, the object type
1.1 cvs 1628: to be included (that is, the name of its structure schema) is followed by a
1.37 cvs 1629: keyword: <tt>EXTERN</tt> for inclusion without expansion and
1630: <tt>INCLUDED</tt> for partial expansion.</p>
1.30 cvs 1631:
1.37 cvs 1632: <p>Before creating a cross-reference or an inclusion, the Thot editor asks
1633: the user to choose, from the document images displayed, the referenced or
1634: included element.</p>
1.30 cvs 1635:
1.18 cvs 1636: <blockquote class="example">
1.30 cvs 1637: <p><strong>Example:</strong></p>
1638:
1639: <p>If the types Note and Section are defined in the Article structure
1640: schema, it is possible to define, in the same structure schema, a reference
1641: to a note and a reference to a section in this manner:</p>
1642: <pre>Ref_note = REFERENCE (Note);
1.18 cvs 1643: Ref_section = REFERENCE (Section);</pre>
1.30 cvs 1644:
1645: <p>It is also possible to define the generic structure of a collection of
1646: articles, which include (with partial expansion) objects of the Article
1647: class and which possess an introduction which may include cross-references
1.37 cvs 1648: to sections of the included articles. In the Collection structure schema,
1.30 cvs 1649: the definitions are:</p>
1650: <pre>Collection = BEGIN
1.6 cvs 1651: Collection_title = TEXT;
1652: Introduction = LIST OF (Elem = CASE OF
1.1 cvs 1653: TEXT;
1654: Ref_sect;
1655: END);
1.6 cvs 1656: Body = LIST OF (Article INCLUDED);
1657: END;
1.18 cvs 1658: Ref_sect = REFERENCE (Section (Article));</pre>
1.30 cvs 1659:
1660: <p>Here we define a Folder document class which has a title and includes
1661: documents of different types, particularly Folders:</p>
1662: <pre>Folder = BEGIN
1.6 cvs 1663: Folder_title = TEXT;
1664: Folder_contents = LIST OF (Document);
1665: END;
1.1 cvs 1666:
1667: Document = CASE OF
1668: Article EXTERN;
1669: Collection EXTERN;
1670: Folder EXTERN;
1.18 cvs 1671: END;</pre>
1.30 cvs 1672:
1673: <p>Under this definition, Folder represents either an aggregate which
1674: contains a folder title and the list of included documents or an included
1.37 cvs 1675: folder. To resolve this ambiguity, in the P language, the placement of a
1.30 cvs 1676: star character in front of the type name (here, Folder) indicates an
1677: included document.</p>
1.18 cvs 1678: </blockquote>
1679: </div>
1.1 cvs 1680:
1.18 cvs 1681: <div class="subsubsection">
1.37 cvs 1682: <h4><a name="sectd3285" id="sectd3285">Mark pairs</a></h4>
1.1 cvs 1683:
1.37 cvs 1684: <p>Like other elements, mark pairs are typed. The two marks of the pair have
1685: the same type, but there exist two predefined subtypes which apply to all
1686: mark pairs: the first mark of the pair (called <tt>First</tt> in the P and T
1.18 cvs 1687: languages) and the second mark (called <tt>Second</tt>).</p>
1.30 cvs 1688:
1689: <p>In the S language, a mark pair is noted simply by the <tt>PAIR</tt>
1.18 cvs 1690: keyword.</p>
1.30 cvs 1691:
1.37 cvs 1692: <p>In the Thot editor, marks are always moved or destroyed together. The two
1.1 cvs 1693: marks of a pair have the same identifier, unique within the document, which
1.18 cvs 1694: permits intertwining mark pairs without risk of ambiguity.</p>
1695: </div>
1696: </div>
1.1 cvs 1697:
1.18 cvs 1698: <div class="subsection">
1.37 cvs 1699: <h3><a name="sectc329" id="sectc329">Imports</a></h3>
1.1 cvs 1700:
1.30 cvs 1701: <p>Because of schema constructors, it is possible, before editing a document,
1.37 cvs 1702: to use classes defined by other structure schemas whenever they are needed.
1703: It is also possible to assign specific document classes to certain element
1704: types. In this case, these classes are simply designated by their name. In
1705: fact, if a type name is not defined in the structure schema, it is assumed
1706: that it specifies a structure defined by another structure schema.</p>
1.30 cvs 1707:
1.18 cvs 1708: <blockquote class="example">
1.30 cvs 1709: <p><strong>Example:</strong></p>
1710:
1711: <p>If the types Math and Table don't appear in the left part of a structure
1712: rule in the schema, the following two rules indicate that a formula has the
1.37 cvs 1713: structure of an object defined by the structure schema Math and that a
1714: table element has the structure of an object defined by the Table
1715: schema.</p>
1.30 cvs 1716: <pre>Formula = Math;
1.18 cvs 1717: Table_elem = Table;</pre>
1718: </blockquote>
1719: </div>
1720:
1721: <div class="subsection">
1.37 cvs 1722: <h3><a name="sectc3210" id="sectc3210">Extension rules</a></h3>
1.18 cvs 1723:
1.30 cvs 1724: <p>The <tt>EXTENS</tt> section, which can only appear in an extension schema,
1.1 cvs 1725: defines complements to the rules in the primary schema (i.e. the structure
1726: schema to which the extension schema will be applied). More precisely, this
1727: section permits the addition to an existing type of local attributes,
1.18 cvs 1728: extensions, restrictions and fixed-value attributes.</p>
1.30 cvs 1729:
1730: <p>These additions can be applied to the root rule of the primary schema,
1.18 cvs 1731: designated by the keyword <tt>Root</tt>, or to any other explicitly named
1732: rule.</p>
1.30 cvs 1733:
1734: <p>Extension rules are separated from each other by a semicolon and each
1.18 cvs 1735: extension rule has the same syntax as a <a href="#sectc327">structure
1736: rule</a>, but the part which defines the constructor is absent.</p>
1.30 cvs 1737: <pre> ExtenRuleSeq = ExtensRule ';' < ExtensRule ';' > .
1.6 cvs 1738: ExtensRule = RootOrElem [ LocAttrSeq ]
1739: [ '+' '(' ExtensionSeq ')' ]
1740: [ '-' '(' RestrictSeq ')' ]
1741: [ 'WITH' FixedAttrSeq ] .
1.18 cvs 1742: RootOrElem = 'Root' / ElemID .</pre>
1743: </div>
1.1 cvs 1744:
1.18 cvs 1745: <div class="subsection">
1.37 cvs 1746: <h3><a name="sectc3212" id="sectc3212">Units</a></h3>
1.30 cvs 1747:
1748: <p>The <tt>UNITS</tt> section of the structure schema contains the
1749: declarations of the element types which can be used in the external objects
1750: making up parts of the document or in objects of the class defined by the
1.37 cvs 1751: schema. These element types are defined just like other structured element
1752: types. They can be used in the other element types of the schema, but they
1753: can also be used in any other rule of the schema.</p>
1.30 cvs 1754:
1755: <blockquote class="example">
1756: <p><strong>Example:</strong></p>
1.1 cvs 1757:
1.30 cvs 1758: <p>If references to notes are declared as units:</p>
1759: <pre>UNITS
1.18 cvs 1760: Ref_note = REFERENCE (Note);</pre>
1.30 cvs 1761:
1.37 cvs 1762: <p>then it is possible to use references to notes in a cell of a table,
1763: even when <tt>Table</tt> is an external structure schema. The
1764: <tt>Table</tt> schema must declare a cell to be a sequence of units, which
1765: can then be base element types (text, for example) or references to notes
1766: in the document.</p>
1.30 cvs 1767: <pre>Cell = LIST OF (UNITS);</pre>
1.18 cvs 1768: </blockquote>
1769: </div>
1.1 cvs 1770:
1.18 cvs 1771: <div class="subsection">
1.37 cvs 1772: <h3><a name="sectc3213" id="sectc3213">Skeleton elements</a></h3>
1.1 cvs 1773:
1.30 cvs 1774: <p>When editing a document which contains or must contain external references
1775: to several other documents, it may be necessary to load a large number of
1.1 cvs 1776: documents, simply to see the parts designated by the external references of
1.37 cvs 1777: the document while editing, or to access the source of included elements. In
1778: this case, the external documents are not modified and it is only necessary
1779: to see the elements of these documents which could be referenced. Because of
1.1 cvs 1780: this, the editor will suggest that the documents be loaded in ``skeleton''
1.37 cvs 1781: form. This form contains only the elements of the document explicitly
1.18 cvs 1782: mentioned in the <tt>EXPORT</tt> section of their structure schema and, for
1.1 cvs 1783: these elements, only the part of the contents specified in that section. This
1784: form has the advantage of being very compact, thus requiring very few
1.37 cvs 1785: resources from the editor. This is also the skeleton form which constitutes
1.18 cvs 1786: the expanded form of <a href="#inclusion">inclusions</a> with partial
1787: expansion.</p>
1.30 cvs 1788:
1789: <p>Skeleton elements must be declared explicitly in the <tt>EXPORT</tt>
1.37 cvs 1790: section of the structure schema that defines them. This section begins with
1.30 cvs 1791: the keyword <tt>EXPORT</tt> followed by a comma-separated list of the element
1.1 cvs 1792: types which must appear in the skeleton form and ending with a semicolon.
1.18 cvs 1793: These types must have been previously declared in the schema.</p>
1.30 cvs 1794:
1.37 cvs 1795: <p>For each skeleton element type, the part of the contents which is loaded
1796: by the editor, and therefore displayable, can be specified by putting the
1797: keyword <tt>WITH</tt> and the name of the contained element type to be loaded
1798: after the name of the skeleton element type. In this case only that named
1799: element, among all the elements contained in the exportable element type,
1800: will be loaded. If the <tt>WITH</tt> is absent, the entire contents of the
1801: skeleton element will be loaded by the editor. If instead, it is better that
1802: the skeleton form not load the contents of a particular element type, the
1803: keyword <tt>WITH</tt> must be followed by the word <tt>Nothing</tt>.</p>
1.18 cvs 1804: <pre> [ 'EXPORT' SkeletonSeq ]
1.1 cvs 1805:
1.30 cvs 1806: SkeletonSeq = SkelElem < ',' SkelElem > ';' .
1.1 cvs 1807: SkelElem = ElemID [ 'WITH' Contents ] .
1.18 cvs 1808: Contents = 'Nothing' / ElemID [ ExtStruct ] .</pre>
1.30 cvs 1809:
1.18 cvs 1810: <blockquote class="example">
1.30 cvs 1811: <p><strong>Example:</strong></p>
1812:
1813: <p>Suppose that, in documents of the article class, the element types
1814: Article_title, Figure, Section, Paragraph, and Biblio should appear in the
1815: skeleton form in order to make it easier to create external references to
1.37 cvs 1816: them from other documents. When loading an article in its skeleton form,
1.30 cvs 1817: all of these element types will be loaded except for paragraphs, but only
1.37 cvs 1818: the article title will be loaded in its entirety. For figures, the caption
1.30 cvs 1819: will be loaded, while for sections, the title will be loaded, and for
1.37 cvs 1820: bibliographic entries, only the title that they contain will be loaded.
1821: Note that bibliographic elements are defined in another structure schema,
1822: RefBib. To produce this result, the following declarations should be placed
1823: in the Article structure schema:</p>
1.30 cvs 1824: <pre>EXPORT
1.1 cvs 1825: Article_title,
1.5 cvs 1826: Figure With Caption,
1.1 cvs 1827: Section With Section_title,
1828: Paragraph With Nothing,
1.18 cvs 1829: Biblio With Biblio_title(RefBib);</pre>
1830: </blockquote>
1831: </div>
1.1 cvs 1832:
1.18 cvs 1833: <div class="subsection">
1.37 cvs 1834: <h3><a name="sectc3214" id="sectc3214">Exceptions</a></h3>
1.1 cvs 1835:
1.30 cvs 1836: <p>The behavior of the Thot editor and the actions that it performs are
1.37 cvs 1837: determined by the structure schemas. These actions are applied to all
1838: document and object types in accordance with their generic structure. For
1.1 cvs 1839: certain object types, such as tables and graphics, these actions are not
1840: sufficient or are poorly adapted and some special actions must be added to or
1.37 cvs 1841: substituted for certain standard actions. These special actions are called
1.18 cvs 1842: <em>exceptions</em>.</p>
1.30 cvs 1843:
1.37 cvs 1844: <p>Exceptions only inhibit or modify certain standard actions, but they can
1845: be used freely in every structure schema.</p>
1.30 cvs 1846:
1.37 cvs 1847: <p>Each structure schema can contain a section defining exceptions. It begins
1.18 cvs 1848: with the keyword <tt>EXCEPT</tt> and is composed of a sequence of exception
1.37 cvs 1849: declarations, separated by semicolons. Each declaration of an exception
1850: begins with the name of an element type or attribute followed by a colon.
1851: This indicates the element type or attribute to which the following
1852: exceptions apply. When the given element type name is a <a
1853: href="#sectd3285">mark pair</a>, and only in this case, the type name can be
1854: preceded by the keyword <tt>First</tt> or <tt>Second</tt>, to indicate if the
1855: exceptions which follow are associated with the first mark of the pair or the
1856: second. In the absence of this keyword, the first mark is used.</p>
1.30 cvs 1857:
1858: <p>When placed in an <a href="#sectc322">extension schema</a>, the keyword
1.18 cvs 1859: <tt>EXTERN</tt> indicates that the type name which follows is found in the
1.37 cvs 1860: principal schema (the schema being extended by the extension schema). The
1861: exceptions are indicated by a name. They are separated by semicolons.</p>
1.18 cvs 1862: <pre> [ 'EXCEPT' ExceptSeq ]
1.1 cvs 1863:
1.30 cvs 1864: ExceptSeq = Except ';' < Except ';' > .
1.1 cvs 1865: Except = [ 'EXTERN' ] [ FirstSec ] ExcTypeOrAttr
1866: ':' ExcValSeq .
1867: ExcTypeOrAttr = ElemID / AttrID .
1.30 cvs 1868: ExcValSeq = ExcValue < ',' ExcValue > .
1.19 cvs 1869: ExcValue ='NoCut' / 'NoCreate' / 'NoHMove' /
1870: 'NoVMove' / 'NoHResize' / 'NoVResize' /
1871: 'NoMove' / 'NoResize' / 'MoveResize' /
1872: 'NewWidth' / 'NewHeight' / 'NewHPos' /
1873: 'NewVPos' / 'Invisible' /
1.28 cvs 1874: 'NoSelect' / 'NoSpellCheck' /
1.1 cvs 1875: 'Hidden' / 'ActiveRef' /
1876: 'ImportLine' / 'ImportParagraph' /
1877: 'NoPaginate' / 'ParagraphBreak' /
1.19 cvs 1878: 'PageBreak' / 'PageBreakAllowed' / 'PageBreakPlace' /
1879: 'PageBreakRepetition' / 'PageBreakRepBefore' /
1.9 cvs 1880: 'HighlightChildren' / 'ExtendedSelection' /
1.36 cvs 1881: 'SelectParent' / 'ClickableSurface' /
1.29 cvs 1882: 'ReturnCreateNL' / 'ReturnCreateWithin' /
1883: 'IsDraw' / 'IsTable' /
1.19 cvs 1884: 'IsRow' / 'IsColHead' / 'IsCell' /
1885: 'NewPercentWidth' / 'ColRef' / 'ColSpan' /
1886: 'RowSpan' / 'SaveDocument' / 'Shadow' .</pre>
1.30 cvs 1887:
1888: <p>The following are the available exceptions:</p>
1.18 cvs 1889: <dl>
1.30 cvs 1890: <dt><tt>NoCut</tt></dt>
1.37 cvs 1891: <dd>This exception can only be applied to element types. Elements of a
1.30 cvs 1892: type to which this exception is applied cannot be deleted by the
1893: editor.</dd>
1894: <dt><tt>NoCreate</tt></dt>
1.37 cvs 1895: <dd>This exception can only be applied to element types. Elements of a
1.30 cvs 1896: type to which this exception is applied cannot be created by ordinary
1.37 cvs 1897: commands for creating new elements. These elements are usually created
1.30 cvs 1898: by special actions associated with other exceptions.</dd>
1899: <dt><tt>NoHMove</tt></dt>
1.37 cvs 1900: <dd>This exception can only be applied to element types. Elements of a
1.30 cvs 1901: type to which this exception is applied cannot be moved horizontally
1902: with the mouse. Their children elements cannot be moved either.</dd>
1903: <dt><tt>NoVMove</tt></dt>
1.37 cvs 1904: <dd>This exception can only be applied to element types. Elements of a
1.30 cvs 1905: type to which this exception is applied cannot be moved vertically with
1906: the mouse. Their children elements cannot be moved either.</dd>
1907: <dt><tt>NoMove</tt></dt>
1.37 cvs 1908: <dd>This exception can only be applied to element types. Elements of a
1909: type to which this exception is applied cannot be moved in any
1910: direction with the mouse. Their children elements cannot be moved
1911: either.</dd>
1.30 cvs 1912: <dt><tt>NoHResize</tt></dt>
1.37 cvs 1913: <dd>This exception can only be applied to element types. Elements of a
1.30 cvs 1914: type to which this exception is applied cannot be resized horizontally
1915: with the mouse. Their children elements cannot be resized either.</dd>
1916: <dt><tt>NoVResize</tt></dt>
1.37 cvs 1917: <dd>This exception can only be applied to element types. Elements of a
1.30 cvs 1918: type to which this exception is applied cannot be resized vertically
1919: with the mouse. Their children elements cannot be resized either.</dd>
1920: <dt><tt>NoResize</tt></dt>
1.37 cvs 1921: <dd>This exception can only be applied to element types. Elements of a
1.30 cvs 1922: type to which this exception is applied cannot be resized in any
1.37 cvs 1923: direction with the mouse. Their children elements cannot be resized
1.30 cvs 1924: either.</dd>
1925: <dt><tt>MoveResize</tt></dt>
1.37 cvs 1926: <dd>This exception can only be applied to element types. Elements of a
1.30 cvs 1927: type to which this exception is applied can be moved and resized in any
1928: direction with the mouse, even if one of their ancestor element has an
1.37 cvs 1929: exception that prevents moving or resizing. Their children elements can
1.30 cvs 1930: also be resized or moved.</dd>
1931: <dt><tt>NewWidth</tt></dt>
1.37 cvs 1932: <dd>This exception can only be applied to numeric attributes. If the
1933: width of an element which has this attribute is modified with the
1934: mouse, the value of the new width will be assigned to the
1935: attribute.</dd>
1.30 cvs 1936: <dt><tt>NewHeight</tt></dt>
1.37 cvs 1937: <dd>This exception can only be applied to numeric attributes. If the
1.30 cvs 1938: height of an element which has this attribute is modified with the
1939: mouse, the value of the new height will be assigned to the
1940: attribute.</dd>
1941: <dt><tt>NewHPos</tt></dt>
1.37 cvs 1942: <dd>This exception can only be applied to numeric attributes. If the
1.30 cvs 1943: horizontal position of an element which has this attribute is modified
1944: with the mouse, the value of the new horizontal position will be
1945: assigned to the attribute.</dd>
1946: <dt><tt>NewVPos</tt></dt>
1.37 cvs 1947: <dd>This exception can only be applied to numeric attributes. If the
1.30 cvs 1948: vertical position of an element which has this attribute is modified
1949: with the mouse, the value of the new vertical position will be assigned
1950: to the attribute.</dd>
1951: <dt><tt>Invisible</tt></dt>
1952: <dd>This exception can only be applied to attributes, but can be applied
1.37 cvs 1953: to all attribute types. It indicates that the attribute must not be
1954: seen by the user and that its value must not be changed directly. This
1.30 cvs 1955: exception is usually used when another exception manipulates the value
1956: of an attribute.</dd>
1957: <dt><tt>NoSelect</tt></dt>
1.37 cvs 1958: <dd>This exception can only be applied to element types. Elements of a
1959: type to which this exception is applied cannot be selected directly
1.30 cvs 1960: with the mouse, but they can be selected by other methods provided by
1961: the editor.</dd>
1962: <dt>NoSpellCheck</dt>
1.37 cvs 1963: <dd>This exception can only be applied to element types. Elements of a
1.30 cvs 1964: type to which this exception is applied are not taken into account by
1965: the spell checker.</dd>
1966: <dt><tt>Hidden</tt></dt>
1.37 cvs 1967: <dd>This exception can only be applied to element types. It indicates
1.30 cvs 1968: that elements of this type, although present in the document's
1.37 cvs 1969: structure, must not be shown to the user of the editor. In particular,
1.30 cvs 1970: the creation menus must not propose this type and the selection message
1971: must not pick it.</dd>
1972: <dt><tt>ActiveRef</tt></dt>
1973: <dd>This exception can only be applied to attributes of the reference
1.37 cvs 1974: type. It indicates that when the user of the editor makes a double
1.30 cvs 1975: click on an element which possesses a reference attribute having this
1976: exception, the element designated by the reference attribute will be
1977: selected.</dd>
1978: <dt><tt>ImportLine</tt></dt>
1.37 cvs 1979: <dd>This exception can only be applied to element types. It indicates
1.30 cvs 1980: that elements of this type should receive the content of imported text
1.37 cvs 1981: files. An element is created for each line of the imported file. A
1.30 cvs 1982: structure schema cannot contain several exceptions <tt>ImportLine</tt>
1983: and, if it contains one, it should not contain any exception
1984: <tt>ImportParagraph</tt>.</dd>
1985: <dt><tt>ImportParagraph</tt></dt>
1.37 cvs 1986: <dd>This exception can only be applied to element types. It indicates
1.30 cvs 1987: that elements of this type should receive the content of imported text
1.37 cvs 1988: files. An element is created for each paragraph of the imported file. A
1989: paragraph is a sequence of lines without any empty line. A structure
1.30 cvs 1990: schema cannot contain several exceptions <tt>ImportParagraph</tt> and,
1991: if it contains one, it should not contain any exception
1992: <tt>ImportLine</tt>.</dd>
1993: <dt><tt>NoPaginate</tt></dt>
1994: <dd>This exception can only be applied to the root element, i.e. the name
1.37 cvs 1995: that appear after the keyword <tt>STRUCTURE</tt> at the beginning of
1996: the structure schema. It indicates that the editor should not allow the
1.30 cvs 1997: user to paginate documents of that type.</dd>
1998: <dt><tt>ParagraphBreak</tt></dt>
1.37 cvs 1999: <dd>This exception can only be applied to element types. When the caret
2000: is within an element of a type to which this exception is applied, it
2001: is that element that will be split when the user hits the Return
2002: key.</dd>
1.30 cvs 2003: <dt><tt>ReturnCreateNL</tt></dt>
1.37 cvs 2004: <dd>This exception can only be applied to element types. When the caret
1.30 cvs 2005: is within an element of a type to which this exception is applied, the
2006: Return key simply inserts a New line character (code \212) at the
2007: current position. The Return key does not create a new element; it does
2008: not split the current element either.</dd>
2009: <dt><tt>ReturnCreateWithin</tt></dt>
1.37 cvs 2010: <dd>This exception can only be applied to element types. When the caret
1.30 cvs 2011: is within an element of a type to which this exception is applied, the
2012: Return key will create a new element within that element, not a sibling
2013: after that element.</dd>
2014: <dt><tt>HighlightChildren</tt></dt>
1.37 cvs 2015: <dd>This exception can only be applied to element types. Elements of a
1.30 cvs 2016: type to which this exception is applied are not highlighted themselves
1.32 cvs 2017: when they are selected in the main view, but all their children are
1.37 cvs 2018: highlighted instead. If children have this exception too, the process
2019: is applied recursively. Only the main view defined in the presentation
1.32 cvs 2020: schema is concerned. Tee exception is ignored for other views.</dd>
1.30 cvs 2021: <dt><tt>ExtendedSelection</tt></dt>
1.37 cvs 2022: <dd>This exception can only be applied to element types. The selection
1.30 cvs 2023: extension command (middle button of the mouse) only add the clicked
2024: element (if it has that exception) to the current selection, without
2025: selecting other elements between the current selection and the clicked
2026: element.</dd>
1.36 cvs 2027: <dt><code>SelectParent</code></dt>
2028: <dd>This exception can only be applied to element types. When the user
1.37 cvs 2029: clicks on an element of that type, the parent of the element is
2030: selected instead of the element itself.</dd>
1.36 cvs 2031: <dt><code>ClickableSurface</code></dt>
2032: <dd>This exception can only be applied to element types. When the user
1.37 cvs 2033: clicks within a child of an element of that type, this child is
2034: selected even if it is a graphic leaf that is not filled.</dd>
1.36 cvs 2035: <dt><code>IsDraw</code>, <code>IsTable</code>, <code>IsColHead</code>,
2036: <code>IsRow</code>, <code>IsCell</code></dt>
1.37 cvs 2037: <dd>These exceptions can only be applied to element types. Elements of a
1.30 cvs 2038: type to which these exceptions are applied are identified as Draws,
2039: Tables, Colheads, Rows or Cells and specific processing are applied to
2040: them.</dd>
1.36 cvs 2041: <dt><code>ColRef</code></dt>
1.30 cvs 2042: <dd>This exception can only be applied to attributes of the reference
2043: type. It indicates that this attribute refers to the column head (see
2044: exception IsColHead) which the element belongs to.</dd>
1.36 cvs 2045: <dt><code>ColSpan</code>, <code>RowSpan</code></dt>
1.31 cvs 2046: <dd>These exceptions can only be applied to numeric attributes of cells.
1.30 cvs 2047: They indicate that attribute values give how many columns or rows the
2048: element spans.</dd>
1.36 cvs 2049: <dt><code>Shadow</code></dt>
1.37 cvs 2050: <dd>This exception can only be applied to element types. Text of elements
1.30 cvs 2051: of a type to which this exception is applied are displayed and printed
2052: as a set of stars ('*').</dd>
1.18 cvs 2053: </dl>
1.30 cvs 2054:
1.18 cvs 2055: <blockquote class="example">
1.30 cvs 2056: <p><strong>Example:</strong></p>
2057:
2058: <p>Consider a structure schema for object-style graphics which defines the
2059: Graphic_object element type with the associated Height and Weight numeric
1.37 cvs 2060: attributes. Suppose that we want documents of this class to have the
1.30 cvs 2061: following qualities:</p>
2062: <ul>
2063: <li>Whenever the width or height of an object is changed using the mouse,
2064: the new values are stored in the object's Width and Height
2065: attributes.</li>
2066: <li>The user should not be able to change the values of the Width and
2067: Height attributes via the Attributes menu of the Thot editor.</li>
2068: </ul>
2069:
2070: <p>The following exceptions will produce this effect.</p>
2071: <pre>STRUCT
1.1 cvs 2072: ...
1.5 cvs 2073: Graphics_object (ATTR Height = Integer; Width = Integer)
1.1 cvs 2074: = GRAPHICS with Height ?= 10, Width ?= 10;
2075: ...
2076: EXCEPT
2077: Height: NewHeight, Invisible;
1.18 cvs 2078: Width: NewWidth, Invisible;</pre>
2079: </blockquote>
2080: </div>
2081: </div>
1.1 cvs 2082:
1.18 cvs 2083: <div class="section">
1.37 cvs 2084: <h2><a name="sectb33" id="sectb33">Some examples</a></h2>
1.1 cvs 2085:
1.30 cvs 2086: <p>In order to illustrate the principles of the document model and the syntax
2087: of the S language, this section presents two examples of structure schemas.
2088: One defines a class of documents, the other defines a class of objects.</p>
1.1 cvs 2089:
1.18 cvs 2090: <div class="subsection">
1.37 cvs 2091: <h3><a name="sectc331" id="sectc331">A class of documents: articles</a></h3>
1.1 cvs 2092:
1.30 cvs 2093: <p>This example shows a possible structure for articles published in a
2094: journal. Text between braces is comments.</p>
1.18 cvs 2095: <pre>STRUCTURE Article; { This schema defines the Article class }
1.1 cvs 2096: DEFPRES ArticleP; { The default presentation schema is
2097: ArticleP }
2098: ATTR { Global attribute definitions }
2099: WordType = Definition, IndexWord, DocumentTitle;
2100: { A single global attribute is defined, with three values }
2101: STRUCT { Definition of the generic structure }
2102: Article = BEGIN { The Article class has an aggregate
2103: structure }
2104: Title = BEGIN { The title is an aggregate }
2105: French_title =
2106: Text WITH Language='Fran\347ais';
2107: English_title =
2108: Text WITH Language='English';
2109: END;
2110: Authors =
2111: LIST OF (Author
2112: (ATTR Author_type=principal,secondary)
2113: { The Author type has a local attribute }
2114: = BEGIN
2115: Author_name = Text;
2116: Info = Paragraphs ;
2117: { Paragraphs is defined later }
2118: Address = Text;
2119: END
2120: );
2121: Keywords = Text;
2122: { The journal's editor introduces the article
2123: with a short introduction, in French and
2124: in English }
2125: Introduction =
2126: BEGIN
2127: French_intr = Paragraphs WITH
2128: Language='Fran\347ais';
2129: English_intr = Paragraphs WITH
2130: Language='English';
2131: END;
2132: Body = Sections; { Sections are defined later }
2133: { Appendixes are only created on demand }
2134: ? Appendices =
2135: LIST OF (Appendix =
2136: BEGIN
2137: Appendix_Title = Text;
2138: Appendix_Contents = Paragraphs;
2139: END
2140: );
1.37 cvs 2141: ? Figures = LIST OF (Figure);
2142: ? Bibliography = LIST OF (Biblio_citation);
2143: ? Notes = LIST OF (Note);
1.1 cvs 2144: END; { End of the Article aggregate }
2145:
2146: Sections = LIST [2..*] OF (
2147: Section = { At least 2 sections }
2148: BEGIN
2149: Section_title = Text;
2150: Section_contents =
2151: BEGIN
2152: Paragraphs;
2153: Sections; { Sections at a lower level }
2154: END;
2155: END
2156: );
2157:
2158: Paragraphs = LIST OF (Paragraph = CASE OF
2159: Enumeration =
2160: LIST [2..*] OF
2161: (Item = Paragraphs);
2162: Isolated_formula = Formula;
2163: LIST OF (UNIT);
2164: END
2165: );
2166:
2167: Figure = BEGIN
1.5 cvs 2168: Figure_caption = Text;
1.1 cvs 2169: Illustration = NATURE;
2170: END;
2171:
2172: Biblio_citation = CASE OF
2173: Ref_Article =
2174: BEGIN
2175: Authors_Bib = Text;
2176: Article_Title = Text;
2177: Journal = Text;
2178: Page_Numbers = Text;
2179: Date = Text;
2180: END;
2181: Ref_Livre =
2182: BEGIN
2183: Authors_Bib; { Defined above }
2184: Book_Title = Text;
2185: Editor = Text;
2186: Date; { Defined above }
2187: END;
2188: END;
2189:
2190: Note = Paragraphs - (Ref_note);
2191:
2192: UNITS { Elements which can be used in objects }
2193:
2194: Ref_note = REFERENCE (Note);
2195: Ref_biblio = REFERENCE (Biblio_citation);
2196: Ref_figure = REFERENCE (Figure);
2197: Ref_formula = REFERENCE (Isolated_formula);
2198:
2199: EXPORT { Skeleton elements }
2200:
2201: Title,
1.5 cvs 2202: Figure with Figure_caption,
1.1 cvs 2203: Section With Section_title;
2204:
1.18 cvs 2205: END { End of the structure schema }</pre>
1.30 cvs 2206:
2207: <p>This schema is very complete since it defines both paragraphs and
1.37 cvs 2208: bibliographic citations. These element types could just as well be defined in
2209: other structure schemas, as is the case with the <tt>Formula</tt> class. All
2210: sorts of other elements can be inserted into an article, since a paragraph
2211: can contain any type of unit. Similarly, figures can be any class of document
2212: or object that the user chooses.</p>
2213:
2214: <p>Generally, an article doesn't contain appendices, but it is possible to
2215: add them on explicit request: this is the effect of the question mark before
2216: the word Appendices.</p>
1.30 cvs 2217:
1.37 cvs 2218: <p>Various types of cross-references can be put in paragraphs. They can also
1.30 cvs 2219: be placed the objects which are part of the article, since the
2220: cross-references are defined as units (<tt>UNITS</tt>).</p>
2221:
2222: <p>There is a single restriction to prevent the creation of Ref_note elements
1.18 cvs 2223: within notes.</p>
1.30 cvs 2224:
2225: <p>It is worth noting that the S language permits the definition of recursive
1.37 cvs 2226: structures like sections: a section can contain other sections (which are
2227: thus at the next lower level of the document tree). Paragraphs are also
2228: recursive elements, since a paragraph can contain an enumeration in which
2229: each element (<tt>Item</tt>) is composed of paragraphs.</p>
1.18 cvs 2230: </div>
1.1 cvs 2231:
1.18 cvs 2232: <div class="subsection">
1.37 cvs 2233: <h3><a name="sectc332" id="sectc332">A class of objects: mathematical
2234: formulas</a></h3>
1.1 cvs 2235:
1.30 cvs 2236: <p>The example below defines the <tt>Formula</tt> class which is used in
1.37 cvs 2237: Article documents. This class represents mathematical formulas with a rather
1.30 cvs 2238: simple structure, but sufficient to produce a correct rendition on the screen
1.37 cvs 2239: or printer. To support more elaborate operations (formal or numeric
2240: calculations), a finer structure should be defined. This class doesn't use
2241: any other class and doesn't define any units.</p>
1.18 cvs 2242: <pre>STRUCTURE Formula;
1.1 cvs 2243: DEFPRES FormulaP;
2244:
2245: ATTR
2246: String_type = Function_name, Variable_name;
2247:
2248: STRUCT
2249: Formula = Expression;
2250: Expression = LIST OF (Construction);
2251: Construction = CASE OF
2252: TEXT; { Simple character string }
2253: Index = Expression;
2254: Exponent = Expression;
2255: Fraction =
2256: BEGIN
1.6 cvs 2257: Numerator = Expression;
1.1 cvs 2258: Denominator = Expression;
2259: END;
2260: Root =
2261: BEGIN
2262: ? Order = TEXT;
2263: Root_Contents = Expression;
2264: END;
2265: Integral =
2266: BEGIN
2267: Integration_Symbol = SYMBOL;
2268: Lower_Bound = Expression;
2269: Upper_Bound = Expression;
2270: END;
2271: Triple =
2272: BEGIN
2273: Princ_Expression = Expression;
2274: Lower_Expression = Expression;
2275: Upper_Expression = Expression;
2276: END;
2277: Column = LIST [2..*] OF
2278: (Element = Expression);
2279: Parentheses_Block =
2280: BEGIN
2281: Opening = SYMBOL;
2282: Contents = Expression;
2283: Closing = SYMBOL;
2284: END;
2285: END; { End of Choice Constructor }
1.18 cvs 2286: END { End of Structure Schema }</pre>
1.30 cvs 2287:
2288: <p>This schema defines a single global attribute which allows functions and
1.37 cvs 2289: variables to be distinguished. In the presentation schema, this attribute can
1.1 cvs 2290: be used to choose between roman (for functions) and italic characters (for
1.18 cvs 2291: variables).</p>
1.30 cvs 2292:
1.37 cvs 2293: <p>A formula's structure is that of a mathematical expression, which is
2294: itself a sequence of mathematical constructions. A mathematical construction
2295: can be either a simple character string, an index, an exponent, a fraction, a
2296: root, etc. Each of these mathematical constructions has a sensible structure
2297: which generally includes one or more expressions, thus making the formula
2298: class's structure definition recursive.</p>
1.30 cvs 2299:
2300: <p>In most cases, the roots which appear in the formulas are square roots and
1.37 cvs 2301: their order (2) is not specified. This is why the Order component is marked
2302: optional by a question mark. When explicitly requested, it is possible to add
1.18 cvs 2303: an order to a root, for example for cube roots (order = 3).</p>
1.30 cvs 2304:
2305: <p>An integral is formed by an integration symbol, chosen by the user (simple
1.37 cvs 2306: integral, double, curvilinear, etc.), and two bounds. A more fine-grained
1.1 cvs 2307: schema would add components for the integrand and the integration variable.
1.37 cvs 2308: Similarly, the Block_Parentheses construction leaves the choice of opening
2309: and closing symbols to the user. They can be brackets, braces, parentheses,
1.18 cvs 2310: etc.</p>
2311: </div>
2312: </div>
1.37 cvs 2313: <hr />
1.18 cvs 2314: </div>
1.1 cvs 2315:
1.18 cvs 2316: <div class="chapter">
1.37 cvs 2317: <h1><a name="sect4" id="sect4">The P Language</a></h1>
1.1 cvs 2318:
1.18 cvs 2319: <div class="section">
1.37 cvs 2320: <h2><a name="sectb41" id="sectb41">Document presentation</a></h2>
1.1 cvs 2321:
1.30 cvs 2322: <p>Because of the model adopted for Thot, the presentation of documents is
1.37 cvs 2323: clearly separated from their structure and content. After having presented
1.1 cvs 2324: the logical structure of documents, we now detail the principles implemented
1.37 cvs 2325: for their presentation. The concept of <em>presentation</em> encompasses what
2326: is often called the page layout, the composition, or the document style. It
1.18 cvs 2327: is the set of operations which display the document on the screen or print it
1.37 cvs 2328: on paper. Like logical structure, document presentation is defined
1.18 cvs 2329: generically with the help of a language, called P.</p>
1.1 cvs 2330:
1.18 cvs 2331: <div class="subsection">
1.37 cvs 2332: <h3><a name="sectc411" id="sectc411">Two levels of presentation</a></h3>
1.1 cvs 2333:
1.30 cvs 2334: <p>The link between structure and presentation is clear: the logical
2335: organization of a document is used to carry out its presentation, since the
2336: purpose of the presentation is to make evident the organization of the
1.37 cvs 2337: document. But the presentation is equally dependent on the device used to
1.30 cvs 2338: render the document. Certain presentation effects, notably changes of font or
1.37 cvs 2339: character set, cannot be performed on all printers or on all screens. This is
1.30 cvs 2340: why Thot uses a two-level approach, where the presentation is first described
2341: in abstract terms, without taking into account each particular device, and
2342: then the presentation is realized within the constraints of a given
2343: device.</p>
2344:
2345: <p>Thus, presentation is only described as a function of the structure of the
1.37 cvs 2346: documents and the image that would be produced on an idealized device. For
1.1 cvs 2347: this reason, presentation descriptions do not refer to any device
1.18 cvs 2348: characteristics: they describe <em>abstract presentations</em> which can be
2349: concretized on different devices.</p>
1.30 cvs 2350:
2351: <p>A presentation description also defines a <em>generic presentation</em>,
2352: since it describes the appearance of a class of documents or objects. This
2353: generic presentation must also be applied to document and object instances,
2354: each conforming to its generic logical structure, but with all the allowances
2355: that were called to mind above: missing elements, constructed elements with
2356: other logical structures, etc.</p>
2357:
2358: <p>In order to preserve the homogeneity between documents and objects,
1.1 cvs 2359: presentation is described with a single set of tools which support the layout
2360: of a large document as well as the composition of objects like a graphical
1.37 cvs 2361: figure or mathematical formula. This unity of presentation description tools
1.1 cvs 2362: contrasts with the traditional approach, which focuses more on documents than
2363: objects and thus is based on the usual typographic conventions, such as the
2364: placement of margins, indentations, vertical spaces, line lengths,
1.18 cvs 2365: justification, font changes, etc.</p>
2366: </div>
1.1 cvs 2367:
1.18 cvs 2368: <div class="subsection">
1.37 cvs 2369: <h3><a name="sectc412" id="sectc412">Boxes</a></h3>
1.1 cvs 2370:
1.37 cvs 2371: <p>To assure the homogeneity of tools, all presentation in Thot, for
2372: documents as well as for the objects which they contain, is based on the
2373: notion of the <em>box</em>, such as was implemented in
2374: T<sub><big>E</big></sub>X.</p>
1.30 cvs 2375:
1.37 cvs 2376: <p>Corresponding to each element of the document is a box, which is the
1.1 cvs 2377: rectangle enclosing the element on the display device (screen or sheet of
1.37 cvs 2378: paper); the outline of this rectangle is not visible, except when a <a
2379: href="#sectc4230a"><tt>ShowBox</tt> rule</a> applies to the element. The
2380: sides of the box are parallel to the sides of the screen or the sheet of
2381: paper. By way of example, a box is associated with a character string, a line
2382: of text, a page, a paragraph, a title, a mathematical formula, or a table
2383: cell.</p>
1.30 cvs 2384:
2385: <p>Whatever element it corresponds to, each box possesses four sides and four
1.18 cvs 2386: axes, which we designate as follows (<a href="#boxes">see figure</a>):</p>
2387: <dl>
1.30 cvs 2388: <dt><tt>Top</tt></dt>
2389: <dd>the upper side,</dd>
2390: <dt><tt>Bottom</tt></dt>
2391: <dd>the lower side,</dd>
2392: <dt><tt>Left</tt></dt>
2393: <dd>the left side,</dd>
2394: <dt><tt>Right</tt></dt>
2395: <dd>the right side,</dd>
2396: <dt><tt>VMiddle</tt></dt>
2397: <dd>the vertical axis passing through the center of the box,</dd>
2398: <dt><tt>HMiddle</tt></dt>
2399: <dd>the horizontal axis passing through the center of the box,</dd>
2400: <dt><tt>VRef</tt></dt>
2401: <dd>the vertical reference axis,</dd>
2402: <dt><tt>HRef</tt></dt>
2403: <dd>the horizontal reference axis.</dd>
1.18 cvs 2404: </dl>
2405:
2406: <div class="figure">
1.37 cvs 2407: <hr />
1.18 cvs 2408: <pre> Left VRef VMiddle Right
1.1 cvs 2409: : :
2410: Top -----------------------------
2411: | : : |
2412: | : : |
2413: | : : |
2414: | : : |
2415: | : : |
2416: HMiddle ..|...........................|..
2417: | : : |
2418: | : : |
2419: HRef ..|...........................|..
2420: | : : |
2421: | : : |
2422: Bottom -----------------------------
1.18 cvs 2423: : :</pre>
1.30 cvs 2424:
1.37 cvs 2425: <p align="center"><em><a name="boxes" id="boxes">The sides and axes of
1.30 cvs 2426: boxes</a><em></em></em></p>
1.37 cvs 2427: <hr />
1.30 cvs 2428: </div>
1.19 cvs 2429:
1.37 cvs 2430: <p>The principal role of boxes is to set the extent and position of the
2431: images of the different elements of a document with respect to each other on
2432: the reproduction device. This is done by defining relations between the boxes
2433: of different elements which give relative extents and positions to these
1.18 cvs 2434: boxes.</p>
1.30 cvs 2435:
2436: <p>There are three types of boxes:</p>
1.18 cvs 2437: <ul>
1.30 cvs 2438: <li>boxes corresponding to structural elements of the document,</li>
2439: <li>presentation boxes,</li>
2440: <li>page layout boxes.</li>
1.18 cvs 2441: </ul>
1.30 cvs 2442:
1.37 cvs 2443: <p><strong>Boxes corresponding to structural elements of the
2444: document</strong> are those which linked to each of the elements (base or
2445: structured) of the logical structure of the document. Such a box contains all
2446: the contents of the element to which it corresponds (there is an exception:
2447: see <a href="#sectc4220">rules <tt>VertOverflow</tt> and
2448: <tt>HorizOverflow</tt></a>). These boxes form a tree-like structure,
2449: identical to that of the structural elements to which they correspond. This
2450: tree expresses the inclusion relationships between the boxes: a box includes
2451: all the boxes of its subtree. On the other hand, there are no predefined
2452: rules for the relative positions of the included boxes. If they are at the
2453: same level, they can overlap, be contiguous, or be disjoint. The rules
2454: expressed in the generic presentation specify their relative positions.</p>
1.30 cvs 2455:
2456: <p><strong>Presentation boxes</strong> represent elements which are not found
1.37 cvs 2457: in the logical structure of the document but which are added to meet the
2458: needs of presentation. These boxes are linked to the elements of the logical
1.30 cvs 2459: structure that are best suited to bringing them out. For example, they are
2460: used to add the character string ``Summary:'' before the summary in the
2461: presentation of a report or to represent the fraction bar in a formula, or
1.37 cvs 2462: also to make the title of a field in a form appear. These elements have no
1.30 cvs 2463: role in the logical structure of the document: the presence of a Summary
2464: element in the document does not require the creation of another structural
1.37 cvs 2465: object to hold the word ``Summary''. Similarly, if a Fraction element
2466: contains both a Numerator element and a Denominator element, the fraction bar
2467: has no purpose structurally. On the other hand, these elements of the
2468: presentation are important for the reader of the reproduced document or for
2469: the user of an editor. This is why they must appear in the document's image.
2470: It is the generic presentation which specifies the presentation boxes to add
2471: by indicating their content (a base element for which the value is specified)
2472: and the position that they must take in the tree of boxes. During editing,
2473: these boxes cannot be modified by the user.</p>
2474:
2475: <p><strong>Page layout boxes</strong> are boxes created implicitly by the
2476: page layout rules. These rules indicate how the contents of a structured
2477: element must be broken into lines and pages. In contrast to presentation
2478: boxes, these line and page boxes do not depend on the logical structure of
2479: the document, but rather on the physical constraints of the output devices:
2480: character size, height and width of the window on the screen or of the sheet
2481: of paper.</p>
1.18 cvs 2482: </div>
1.1 cvs 2483:
1.18 cvs 2484: <div class="subsection">
1.37 cvs 2485: <h3><a name="sectc413" id="sectc413">Views and visibility</a></h3>
1.1 cvs 2486:
1.30 cvs 2487: <p>One of the operations that one might wish to perform on a document is to
1.37 cvs 2488: view it is different ways. For this reason, it is possible to define several
1.18 cvs 2489: <em>views</em> for the same document, or better yet, for all documents of the
1.37 cvs 2490: same class. A view is not a different presentation of the document, but
1.1 cvs 2491: rather a filter which only allows the display of certain parts of the
1.37 cvs 2492: document. For example, it might be desirable to see only the titles of
1.1 cvs 2493: chapters and sections in order to be able to move rapidly through the
1.37 cvs 2494: document. Such a view could be called a ``table of contents''. It might also
1.1 cvs 2495: be desirable to see only the mathematical formulas of a document in order to
1.37 cvs 2496: avoid being distracted by the non-mathematical aspects of the document. A
1.18 cvs 2497: ``mathematics'' view could provide this service.</p>
1.30 cvs 2498:
2499: <p>Views, like presentation, are based on the generic logical structure. Each
1.1 cvs 2500: document class, and each generic presentation, can be provided with views
1.37 cvs 2501: which are particularly useful for that class or presentation. For each view,
1.18 cvs 2502: the <em>visibility</em> of elements is defined, indicated whether or not the
1.37 cvs 2503: elements must be presented to the user. The visibility is calculated as a
1.1 cvs 2504: function of the type of the elements or their hierarchical position in the
1.37 cvs 2505: structure of the document. Thus, for a table of contents, all the ``Chapter
2506: Title'' and ``Section Title'' elements are made visible. However, the
1.1 cvs 2507: hierarchical level could be used to make the section titles invisible below a
1.37 cvs 2508: certain threshold level. By varying this threshold, the granularity of the
2509: view can be varied. In the ``mathematics'' view, only Formula elements would
1.18 cvs 2510: be made visible, no matter what their hierarchical level.</p>
1.30 cvs 2511:
2512: <p>Because views are especially useful for producing a synthetic image of the
1.1 cvs 2513: document, it is necessary to adapt the presentation of the elements to the
1.37 cvs 2514: view in which they appear. For example, it is inappropriate to have a page
2515: break before every chapter title in the table of contents. Thus, generic
1.1 cvs 2516: presentations take into account the possible views and permit each element
1.18 cvs 2517: type's presentation to vary according the view in which its image appears.</p>
2518: </div>
1.1 cvs 2519:
1.18 cvs 2520: <div class="subsection">
1.37 cvs 2521: <h3><a name="sectc414" id="sectc414">Pages</a></h3>
1.1 cvs 2522:
1.30 cvs 2523: <p>Presentation schemas can be defined which display the document as a long
1.37 cvs 2524: scroll, without page breaks. This type of schema is particularly well-suited
1.1 cvs 2525: to the initial phase of work on a document, where jumps from page to page
1.37 cvs 2526: would hinder composing and reading the document on a screen. But, once the
2527: document is written, it may be desirable to display the document on the
2528: screen in the same manner in which it will be printed. So, the presentation
2529: schema must define pages.</p>
2530:
2531: <p>The P language permits the specification of the dimensions of pages as
2532: well as their composition. It is possible to generate running titles, page
2533: numbers, zones at the bottom of the page for notes, etc. The editor follows
1.30 cvs 2534: this model and inserts page break marks in the document which are used during
2535: printing, insuring that the pages on paper are the same as on the screen.</p>
2536:
2537: <p>Once a document has been edited with a presentation schema defining pages,
1.37 cvs 2538: it contains page marks. But it is always possible to edit the document using
2539: a schema without pages. In this case, the page marks are simply ignored by
2540: the editor. They are considered again as soon as a schema with pages is used.
1.18 cvs 2541: Thus, the user is free to choose between schemas with and without pages.</p>
1.30 cvs 2542:
2543: <p>Thot treats the page break, rather than the page itself, as a box. This
2544: page break box contains all the elements of one page's footer, a rule marking
1.37 cvs 2545: the edge of this page, and all the elements of the next page's header. The
2546: elements of the header and footer can be running titles, page number, notes,
2547: etc. All these elements, as well as their content and graphical appearance,
2548: are defined by the generic presentation.</p>
1.18 cvs 2549: </div>
1.1 cvs 2550:
1.18 cvs 2551: <div class="subsection">
1.37 cvs 2552: <h3><a name="sectc415" id="sectc415">Numbering</a></h3>
1.1 cvs 2553:
1.30 cvs 2554: <p>Many elements are numbered in documents: pages, chapters, sections,
2555: formulas, theorems, notes, figures, bibliographic references, exercises,
1.37 cvs 2556: examples, lemmas, etc. Because Thot has a notion of logical structure, all of
1.30 cvs 2557: these numbers (with the exception of pages) are redundant with information
1.37 cvs 2558: implicit in the logical structure of the document. Such numbers are simply a
2559: way to make the structure of the document more visible. So, they are part of
1.30 cvs 2560: the document's presentation and are calculated by the editor from the logical
1.37 cvs 2561: structure. The structure does not contain numbers as such; it only defines
1.1 cvs 2562: relative structural positions between elements, which serve as ordering
1.18 cvs 2563: relations on these elements.</p>
1.30 cvs 2564:
2565: <p>If the structure schema defines the body of a document as a sequence of at
1.18 cvs 2566: least two chapters:</p>
2567: <pre>Body = LIST [2..*] OF Chapter;</pre>
1.30 cvs 2568:
2569: <p>the sequence defined by the list constructor is ordered and each chapter
1.37 cvs 2570: can be assigned a number based on its rank in the Body list. Therefore, all
2571: elements contained in lists a the structure of a document can be numbered,
2572: but they are not the only ones. The tree structure induced by the aggregate,
1.18 cvs 2573: list, and choice constructors (excluding references) defines a total order on
1.37 cvs 2574: the elements of the document's primary structure. So, it is possible to
1.18 cvs 2575: define a numbering which uses this order, filtering elements according to
2576: their type so that only certain element types are taken into account in the
1.37 cvs 2577: numbering. In this way, it possible to number all the theorems and lemmas of
1.18 cvs 2578: a chapter in the same sequence of numbers, even when they are not part of the
2579: same list constructor and appear at different levels of the document's tree.
2580: By changing the filter, they can be numbered separately: one sequence of
2581: numbers for theorems, another for the lemmas.</p>
1.30 cvs 2582:
2583: <p>Since they are calculated from the document's logical structure and only
2584: for the needs of the presentation, numbers are presentation elements,
2585: described by presentation boxes, just like the fraction bar or the word
1.37 cvs 2586: ``Summary''. Nevertheless, numbers differ from these other boxes because
2587: their content varies from instance to instance, even though they are of the
2588: same type, whereas all fraction bars are horizontal lines and the same word
1.30 cvs 2589: ``Summary'' appears at the head of every document's summary.</p>
1.18 cvs 2590: </div>
1.1 cvs 2591:
1.18 cvs 2592: <div class="subsection">
1.37 cvs 2593: <h3><a name="sectc416" id="sectc416">Presentation properties</a></h3>
1.1 cvs 2594:
1.34 cvs 2595: <p>The principal properties which determine document presentation are the
1.18 cvs 2596: <em>positions</em> and <em>dimensions</em> of boxes, the <em>font</em>, the
2597: <em>style</em>, the <em>size</em>, the <em>underlining</em> and the
1.37 cvs 2598: <em>color</em> of their content. From these properties, and some others of
1.34 cvs 2599: less importance, it is possible to represent the usual typographic properties
1.37 cvs 2600: for the textual parts of the document. These same properties can be used to
1.1 cvs 2601: describe the geometry of the non-textual elements, even though they are
1.18 cvs 2602: two-dimensional elements unlike the text, which is linear.</p>
1.30 cvs 2603:
1.37 cvs 2604: <p>As we have already seen, the positions of the boxes always respect the
1.30 cvs 2605: rule of enclosure: a box in the tree encloses all the boxes of the next lower
1.37 cvs 2606: level which are attached to it. The positional properties permit the
1.30 cvs 2607: specification of the position of each box in relation to the enclosing box or
1.37 cvs 2608: to its sibling boxes (boxes directly attached to the same enclosing box in
2609: the tree of boxes).</p>
1.30 cvs 2610:
1.37 cvs 2611: <p>The presentation properties also provide control over the dimensions of
2612: the boxes. The dimensions of a box can depend either on its content or on its
1.1 cvs 2613: context (its sibling boxes and the enclosing box). Each dimension (height or
1.18 cvs 2614: width) can be defined independently of the other.</p>
1.30 cvs 2615:
1.34 cvs 2616: <p>Because of the position and dimension properties, it is possible to do the
1.1 cvs 2617: same things that are normally done in typography by changing margins, line
1.37 cvs 2618: lengths, and vertical or horizontal skips. This approach can also align or
1.18 cvs 2619: center elements and groups of elements.</p>
1.30 cvs 2620:
1.34 cvs 2621: <p>In contrast to the position and dimension properties, the font, style,
1.30 cvs 2622: size, underlining, and color do not concern the box itself (the rectangle
1.37 cvs 2623: delimiting the element), but its content. These properties indicate the
2624: typographic attributes which must be applied to the text contained in the
2625: box, and by extension, to all base elements.</p>
1.30 cvs 2626:
1.34 cvs 2627: <p>For text, the font property is used to change the family of characters
1.1 cvs 2628: (Times, Helvetica, Courier, etc.); the style is used to obtain italic or
1.37 cvs 2629: roman, bold or light characters; the size determines the point size of the
1.1 cvs 2630: characters; underlining defines the type and thickness of the lines drawn
1.18 cvs 2631: above, below, or through the characters.</p>
1.30 cvs 2632:
1.34 cvs 2633: <p>For graphics, the line style property can be either solid, dotted, or
2634: dashed; the line thickness property controls the width of the lines; the fill
2635: pattern property determines how closed geometric figures must be filled.</p>
1.30 cvs 2636:
1.34 cvs 2637: <p>While some of the properties which determine the appearance of a box's
1.1 cvs 2638: contents make sense only for one content type (text or graphic), other
1.34 cvs 2639: properties apply to all content types: these are the color properties. These
1.18 cvs 2640: indicate the color of lines and the background color.</p>
2641: </div>
2642: </div>
1.1 cvs 2643:
1.18 cvs 2644: <div class="section">
1.37 cvs 2645: <h2><a name="sectb42" id="sectb42">Presentation description language</a></h2>
1.30 cvs 2646:
1.34 cvs 2647: <p>A generic presentation defines the values of presentation properties (or
1.37 cvs 2648: the way to calculate those values) for a generic structure, or more
2649: precisely, for all the element types and all the global and local attributes
2650: defined in that generic structure. This definition of the presentation
2651: properties is made with the P language. A program written in this language,
2652: that is a generic presentation expressed in P, is call a <em>presentation
2653: schema</em>. This section describes the syntax and semantics of the language,
2654: using the same <a href="#sectc321">meta-language</a> as was used for the
2655: definition of the S language.</p>
2656:
2657: <p>Recall that it is possible to write many different presentation schemas
2658: for the same class of documents or objects. This allows users to choose for a
2659: document the graphical appearance which best suits their type of work or
1.18 cvs 2660: their personal taste.</p>
1.1 cvs 2661:
1.18 cvs 2662: <div class="subsection">
1.37 cvs 2663: <h3><a name="sectc421" id="sectc421">The organization of a presentation
2664: schema</a></h3>
1.1 cvs 2665:
1.30 cvs 2666: <p>A presentation schema begins with the word <tt>PRESENTATION</tt> and ends
1.37 cvs 2667: with the word <tt>END</tt>. The word <tt>PRESENTATION</tt> is followed by the
2668: name of the generic structure to which the presentation will be applied. This
1.30 cvs 2669: name must be the same as that which follows the keyword <tt>STRUCTURE</tt> in
2670: the structure schema associated with the presentation schema.</p>
2671:
1.37 cvs 2672: <p>After this declaration of the name of the structure, the following
2673: sections appear (in order):</p>
1.18 cvs 2674: <ul>
1.37 cvs 2675: <li>Declarations of
1.30 cvs 2676: <ul>
2677: <li>all views,</li>
2678: <li>printed views,</li>
2679: <li>counters,</li>
2680: <li>presentation constants,</li>
2681: <li>variables,</li>
2682: </ul>
2683: </li>
2684: <li>default presentation rules,</li>
2685: <li>presentation box and page layout box definitions,</li>
2686: <li>presentation rules for structured elements,</li>
2687: <li>presentation rules for attributes,</li>
2688: <li>rules for transmitting values to attributes of included documents.</li>
1.18 cvs 2689: </ul>
1.30 cvs 2690:
2691: <p>Each of these sections is introduced by a keyword which is followed by a
1.37 cvs 2692: sequence of declarations. Every section is optional.</p>
1.18 cvs 2693: <pre> SchemaPres ='PRESENTATION' ElemID ';'
1.1 cvs 2694: [ 'VIEWS' ViewSeq ]
2695: [ 'PRINT' PrintViewSeq ]
2696: [ 'COUNTERS' CounterSeq ]
2697: [ 'CONST' ConstSeq ]
2698: [ 'VAR' VarSeq ]
2699: [ 'DEFAULT' ViewRuleSeq ]
2700: [ 'BOXES' BoxSeq ]
2701: [ 'RULES' PresentSeq ]
2702: [ 'ATTRIBUTES' PresAttrSeq ]
2703: [ 'TRANSMIT' TransmitSeq ]
2704: 'END' .
1.18 cvs 2705: ElemID = NAME .</pre>
2706: </div>
1.1 cvs 2707:
1.18 cvs 2708: <div class="subsection">
1.37 cvs 2709: <h3><a name="sectc422" id="sectc422">Views</a></h3>
1.1 cvs 2710:
1.37 cvs 2711: <p>Each of the possible views must be declared in the presentation schema. As
2712: has <a href="#views">already been described</a>, the presentation rules for
2713: an element type can vary according to the view in which the element appears.
2714: The name of the view is used to designate the view to which the presentation
2715: rules apply (see the <a href="#inkeyword"><tt>IN</tt> instruction</a>). The
1.1 cvs 2716: definition of the view's contents are dispersed throughout the presentation
1.37 cvs 2717: rules attached to the different element types and attributes. The
1.18 cvs 2718: <tt>VIEWS</tt> section is simply a sequence of view names separated by commas
2719: and terminated by a semi-colon.</p>
1.30 cvs 2720:
2721: <p>One of the view names (and only one) can be followed by the keyword
1.37 cvs 2722: <tt>EXPORT</tt>. This keyword identifies the view which presents the members
2723: of the document class in <a href="#sectc3213">skeleton form</a>. The
2724: graphical appearance and the content of this view is defined just as with
1.18 cvs 2725: other views, but it is useless to specify presentation rules concerning this
2726: view for the elements which are not loaded in the skeleton form.</p>
1.30 cvs 2727:
2728: <p>It is not necessary to declare any views; in this case there is a single
1.37 cvs 2729: unnamed view. If many views are declared, the first view listed is considered
2730: the principal view. The principal view is the one to which all rules that are
1.18 cvs 2731: not preceded by an indication of a view will apply (see the <a
2732: href="#inkeyword">instruction <tt>IN</tt></a>).</p>
1.30 cvs 2733:
2734: <p>The principal view is the the one which the editor presents on the screen
1.37 cvs 2735: when the user asks to create or edit a document. Thus, it makes sense to put
2736: the most frequently used view at the head of the list. But if the structure
1.18 cvs 2737: schema contains <a href="#sectc3213">skeleton elements</a> and is loaded in
2738: its skeleton form, the view whose name is followed by the keyword
2739: <tt>EXPORT</tt> will be opened and no other views can be opened.</p>
2740: <pre> 'VIEWS' ViewSeq
1.1 cvs 2741: ViewSeq = ViewDeclaration
1.30 cvs 2742: < ',' ViewDeclaration > ';' .
1.1 cvs 2743: ViewDeclaration = ViewID [ 'EXPORT' ] .
1.18 cvs 2744: ViewID = NAME .</pre>
1.30 cvs 2745:
1.18 cvs 2746: <blockquote class="example">
1.30 cvs 2747: <p><strong>Example:</strong></p>
2748:
2749: <p>When editing a report, it might be useful have views of the table of
1.37 cvs 2750: contents and of the mathematical formulas, in addition to the principal
2751: view which shows the document in its entirety. To achieve this, a
2752: presentation schema for the Report class would have the following
2753: <tt>VIEWS</tt> section:</p>
1.30 cvs 2754: <pre>VIEWS
1.18 cvs 2755: Full_text, Table_of_contents, Formulas;</pre>
1.30 cvs 2756:
2757: <p>The contents of these views are specified in the presentation rules of
2758: the schema.</p>
1.18 cvs 2759: </blockquote>
2760: </div>
1.1 cvs 2761:
1.18 cvs 2762: <div class="subsection">
1.37 cvs 2763: <h3><a name="sectc423" id="sectc423">Print Views</a></h3>
1.1 cvs 2764:
1.37 cvs 2765: <p>When editing a document, each view specified by the <tt>VIEWS</tt>
2766: instruction is presented in a different window.</p>
1.30 cvs 2767:
2768: <p>When printing a document, it is possible to print any number of views,
1.37 cvs 2769: chosen from among all the views which the editor can display. Print views, as
2770: well as the order in which they must be printed, are indicated by the
2771: <tt>PRINT</tt> instruction. It appears after the <tt>VIEWS</tt> instruction
2772: and is formed of the keyword <tt>PRINT</tt> followed by the ordered list of
2773: print view names. The print view names are separated by commas and followed
2774: by a semi-colon. A print view name is a view name declared in the
2775: <tt>VIEWS</tt> instruction.</p>
1.18 cvs 2776: <pre> 'PRINT' PrintViewSeq
1.30 cvs 2777: PrintViewSeq = PrintView < ',' PrintView > ';' .
1.37 cvs 2778: PrintView = ViewID .</pre>
1.30 cvs 2779:
2780: <p>If the <tt>PRINT</tt> instruction is absent, the printing program will
2781: print only the principal view (the first view specified by the <tt>VIEWS</tt>
1.18 cvs 2782: instruction or the single, unnamed view when there is no <tt>VIEWS</tt>
2783: instruction).</p>
1.30 cvs 2784:
1.18 cvs 2785: <blockquote class="example">
1.30 cvs 2786: <p><strong>Example:</strong></p>
2787:
2788: <p>Consider a Report presentation using the view declarations from the
1.37 cvs 2789: preceding example. Suppose we want to print the full text and table of
1.30 cvs 2790: contents views, but not the Formulas view, which is only useful when
1.37 cvs 2791: editing. A sensible printing order would be to print the full text followed
2792: by the table of contents. To obtain this result when printing, the
2793: presentation schema would say:</p>
1.30 cvs 2794: <pre>PRINT
1.37 cvs 2795: Full_text, Table_of_contents;</pre>
1.18 cvs 2796: </blockquote>
2797: </div>
2798:
2799: <div class="subsection">
1.37 cvs 2800: <h3><a name="sectc424" id="sectc424">Counters</a></h3>
1.18 cvs 2801:
1.30 cvs 2802: <p>A presentation has a <em>counter</em> for each type of number in the
1.37 cvs 2803: presentation. All counters, and therefore all types of numbers, used in the
1.18 cvs 2804: schema must be declared after the <tt>COUNTERS</tt> keyword.</p>
1.30 cvs 2805:
2806: <p>Each counter declaration is composed of a name identifying the counter
1.1 cvs 2807: followed by a colon and the counting function to be applied to the counter.
1.18 cvs 2808: The counter declaration ends with a semi-colon.</p>
1.30 cvs 2809:
2810: <p>The counting function indicates how the counter values will be calculated.
1.37 cvs 2811: Three types of counting functions are available. The first type is used to
1.16 cvs 2812: count the elements of a list or aggregate: it assigns to the counter the rank
1.37 cvs 2813: of the element in the list or aggregate. More precisely, the function</p>
1.18 cvs 2814: <pre>RANK OF ElemID [ LevelAsc ] [ INIT AttrID ]
2815: [ 'REINIT' AttrID ]</pre>
1.30 cvs 2816:
2817: <p>indicates that when an element creates, by a creation rule (see the <a
1.18 cvs 2818: href="#sectc4232"><tt>Create</tt> instructions</a>), a presentation box
1.37 cvs 2819: containing the counter value, this value is the rank of the creating element,
1.18 cvs 2820: if it is of type <tt>ElemID</tt>, otherwise the rank of the first element of
2821: type <tt>ElemID</tt> which encloses the creating element in the logical
2822: structure of the document.</p>
1.30 cvs 2823:
2824: <p>The type name can be preceded by a star in the special case where the
1.18 cvs 2825: structure schema defines an element of whose <tt>ElemID</tt> is the same as
2826: that of an <a href="#sectd3284">inclusion</a> without expansion or with
1.37 cvs 2827: partial expansion. To resolve this ambiguity, the <tt>ElemID</tt> alone
1.18 cvs 2828: refers to the type defined in the structure schema while the <tt>ElemID</tt>
2829: preceded by a star refers to the included type.</p>
1.30 cvs 2830:
1.37 cvs 2831: <p>The type name <tt>ElemID</tt> can be followed by an integer. That number
2832: represents the relative level, among the ancestors of the creating element,
2833: of the element whose rank is asked. If that relative level <i>n</i> is
2834: unsigned, the <i>n</i><sup>th</sup> element of type <tt>ElemID</tt>
2835: encountered when travelling the logical structure from the root to the
2836: creating element is taken into account. If the relative level is negative,
2837: the logical structure is travelled in the other direction, from the creating
2838: element to the root.</p>
1.30 cvs 2839:
1.37 cvs 2840: <p>The function can end with the keyword <tt>INIT</tt> followed by the name
2841: of a numeric attribute (and only a numeric attribute). Then, the rank of the
1.30 cvs 2842: first element of the list or aggregate is considered to be the value of this
1.1 cvs 2843: attribute, rather than the default value of 1, and the rank of the other
1.37 cvs 2844: elements is shifted accordingly. The attribute which determines the initial
1.18 cvs 2845: value is searched on the element itself and on its ancestors.</p>
1.30 cvs 2846:
2847: <p>The function can end with the keyword <tt>REINIT</tt> followed by the name
1.37 cvs 2848: of a numeric attribute (and only a numeric attribute). Then, if an element to
1.30 cvs 2849: be counted has this attribute, the counter value for this element is the
1.1 cvs 2850: attribute value and the following elements are numbered starting from this
1.18 cvs 2851: value.</p>
1.30 cvs 2852:
2853: <p>When the <tt>RANK</tt> function is written</p>
1.18 cvs 2854: <pre>RANK OF Page [ ViewID ] [ INIT AttrID ]</pre>
1.30 cvs 2855:
2856: <p>(<tt>Page</tt>is a keyword of the P language), the counter takes as its
2857: value the number of the page on which the element which creates the
1.37 cvs 2858: presentation box containing the number appears. This is done as if the pages
2859: of the document form a list for each view. The counter only takes into
1.30 cvs 2860: account the pages of the relevant view, that is the view displaying the
1.37 cvs 2861: presentation box whose contents take the value of the number. However, if the
2862: keyword <tt>Page</tt> is followed by the name of a view (between
2863: parentheses), it is the pages of that view that are taken into account. As in
2864: the preceding form, the <tt>RANK</tt> function applied to pages can end with
2865: the <tt>INIT</tt> keyword followed by the name of a numeric attribute which
2866: sets the value of the first page's number. This attribute must be a local
1.30 cvs 2867: attribute of the document itself, and not of one of its components.</p>
2868:
2869: <p>The second counting function is used to count the occurrences of a certain
1.37 cvs 2870: element type in a specified context. The instruction</p>
1.18 cvs 2871: <pre>SET n ON Type1 ADD m ON Type2 [ INIT AttrID ]</pre>
1.30 cvs 2872:
2873: <p>says that when the document is traversed from beginning to end (in the
2874: order induced by the logical structure), the counter is assigned the value
1.18 cvs 2875: <tt>n</tt> each time an element of type <tt>Type1</tt> is encountered, no
2876: matter what the current value of the counter, and the value <tt>m</tt> is
2877: added to the current value of the counter each time an element of type
2878: <tt>Type2</tt> is encountered.</p>
1.30 cvs 2879:
2880: <p>As with the <tt>RANK</tt> function, the type names can be preceded by a
2881: star to resolve the ambiguity of included elements.</p>
2882:
1.37 cvs 2883: <p>If the function ends with the keyword <tt>INIT</tt> followed by the name
2884: of an attribute and if the document possesses this attribute, the value of
2885: this attribute is used in place of <tt>n</tt>. The attribute must be numeric.
2886: It is searched on the element itself and on its ancestors.</p>
1.30 cvs 2887:
2888: <p>This function can also be used with the <tt>Page</tt> keyword in the place
1.37 cvs 2889: of <tt>Type1</tt> or <tt>Type2</tt>. In the first case, the counter is
1.18 cvs 2890: reinitialized on each page with the value <tt>n</tt>, while in the second
1.37 cvs 2891: case, it is incremented by <tt>m</tt> on each page. As with the preceding
1.18 cvs 2892: counting function, the word <tt>Page</tt> can be followed by a name between
1.37 cvs 2893: parentheses. In this case, the name specifies a view whose pages are taken
1.18 cvs 2894: into account.</p>
1.30 cvs 2895:
2896: <p>The definition of a counter can contain several <tt>SET</tt> functions and
1.37 cvs 2897: several <tt>ADD</tt> functions, each with a different value. The total number
1.18 cvs 2898: of counting functions must not be greater than 6.</p>
1.30 cvs 2899:
1.37 cvs 2900: <p>The third counting function is used to count the elements of a certain
2901: type encountered when travelling from the creating element to the root of the
2902: logical structure. The creating element is included if it is of that type.
1.18 cvs 2903: That function is written</p>
2904: <pre>RLEVEL OF Type</pre>
1.30 cvs 2905:
2906: <p>where <tt>Type</tt> represents the type of the elements to be counted.</p>
2907:
2908: <p>The formal definition of counter declarations is:</p>
1.18 cvs 2909: <pre> 'COUNTERS' CounterSeq
1.30 cvs 2910: CounterSeq = Counter < Counter > .
1.1 cvs 2911: Counter = CounterID ':' CounterFunc ';' .
2912: CounterID = NAME .
2913: CounterFunc = 'RANK' 'OF' TypeOrPage [ SLevelAsc ]
1.16 cvs 2914: [ 'INIT' AttrID ] [ 'REINIT' AttrID ] /
1.30 cvs 2915: SetFunction < SetFunction >
2916: AddFunction < AddFunction >
1.16 cvs 2917: [ 'INIT' AttrID ] /
2918: 'RLEVEL' 'OF' ElemID .
1.1 cvs 2919: SLevelAsc = [ '-' ] LevelAsc .
2920: LevelAsc = NUMBER .
2921: SetFunction = 'SET' CounterValue 'ON' TypeOrPage .
2922: AddFunction = 'ADD' CounterValue 'ON' TypeOrPage .
2923: TypeOrPage = 'Page' [ '(' ViewID ')' ] /
1.16 cvs 2924: [ '*' ] ElemID .
1.18 cvs 2925: CounterValue = NUMBER .</pre>
1.30 cvs 2926:
1.18 cvs 2927: <blockquote class="example">
1.30 cvs 2928: <p><strong>Example:</strong></p>
2929:
2930: <p>If the body of a chapter is defined as a sequence of sections in the
2931: structure schema:</p>
2932: <pre>Chapter_body = LIST OF (Section =
1.1 cvs 2933: BEGIN
2934: Section_Title = Text;
2935: Section_Body = Paragraphs;
2936: END
1.18 cvs 2937: );</pre>
1.30 cvs 2938:
2939: <p>the section counter is declared:</p>
2940: <pre>SectionCtr : RANK OF Section;</pre>
2941:
2942: <p>and the display of the section number before the section title is
2943: obtained by a <a href="#sectc4232"><tt>CreateBefore</tt> rule</a> attached
2944: the <tt>Section_Title</tt> type, which creates a presentation box whose
2945: content is the value of the <tt>SectionCtr</tt> counter (see the <a
2946: href="#sectc4231"><tt>Content</tt> instruction</a>).</p>
2947:
2948: <p>In order to number the formulas separately within each chapter, the
2949: formula counter is declared:</p>
2950: <pre>FormulaCtr : SET 0 ON Chapter ADD 1 ON Formula;</pre>
2951:
1.37 cvs 2952: <p>and the display of the formula number in the right margin, alongside
2953: each formula, is obtained by a <tt>CreateAfter</tt> instruction attached to
2954: the <tt>Formula</tt> type, which creates a presentation box whose content
2955: is the value of the <tt>FormulaCtr</tt> counter.</p>
1.30 cvs 2956:
2957: <p>To number the page chapter by chapter, with the first page of each
2958: chapter having the number 1, the counter definition would be</p>
2959: <pre>ChapterPageCtr : SET 0 ON Chapter ADD 1 ON Page;</pre>
2960:
2961: <p>If there is also a chapter counter</p>
2962: <pre>ChapterCtr : RANK OF Chapter;</pre>
2963:
1.37 cvs 2964: <p>the <a href="#sectc4231">content</a> of a presentation box created at
2965: the top of each page could be defined as:</p>
1.30 cvs 2966: <pre>Content : (VALUE(ChapterCtr, URoman) TEXT '-'
1.18 cvs 2967: VALUE(ChapterPageCtr, Arabic));</pre>
1.30 cvs 2968:
2969: <p>Thus, the presentation box contains the number of the chapter in
2970: upper-case roman numerals followed by a hyphen and the number of the page
2971: within the chapter in arabic numerals.</p>
1.18 cvs 2972: </blockquote>
1.30 cvs 2973:
1.18 cvs 2974: <blockquote class="example">
1.30 cvs 2975: <p><strong>Example:</strong></p>
2976:
1.37 cvs 2977: <p>To count tables and figures together in a document of the chapter type,
2978: a counter could be defined using:</p>
1.30 cvs 2979: <pre>CommonCtr : SET 0 ON Chapter ADD 1 ON Table
1.18 cvs 2980: ADD 1 ON Figure;</pre>
2981: </blockquote>
2982: </div>
1.1 cvs 2983:
1.18 cvs 2984: <div class="subsection">
1.37 cvs 2985: <h3><a name="sectc425" id="sectc425">Presentation constants</a></h3>
1.1 cvs 2986:
1.30 cvs 2987: <p>Presentation constants are used in the definition of the content of
1.37 cvs 2988: presentation boxes. This content is used in <a href="#sectc426">variable
2989: definitions</a> and in the <a href="#sectc4231"><tt>Content</tt> rule</a>.
2990: The only presentation constants which can be used are character strings,
1.2 cvs 2991: mathematical symbols, graphical elements, and pictures, that is to say, base
1.18 cvs 2992: elements.</p>
1.30 cvs 2993:
2994: <p>Constants can be defined directly in the variables or presentation boxes
1.37 cvs 2995: (<tt>Content</tt> rule) which use them. But it is only necessary them to
1.1 cvs 2996: declare once, in the constant declaration section, even though they are used
1.37 cvs 2997: in many variables or boxes. Thus, each declared constant has a name, which
1.1 cvs 2998: allows it to be designated whenever it is used, a type (one of the four base
2999: types) and a value (a character string or a single character for mathematical
1.18 cvs 3000: symbols and graphical elements).</p>
1.30 cvs 3001:
1.37 cvs 3002: <p>The constant declarations appear after the keyword <tt>CONST</tt>. Each
3003: declaration is composed of the name of the constant, an equals sign, a
3004: keyword representing its type (<tt>Text</tt>, <tt>Symbol</tt>,
3005: <tt>Graphics</tt> or <tt>Picture</tt>) and the string representing its value.
3006: A semi-colon terminates each declaration.</p>
1.30 cvs 3007:
3008: <p>In the case of a character string, the keyword <tt>Text</tt> can be
3009: followed by the name of an alphabet (for example, <tt>Greek</tt> or
1.37 cvs 3010: <tt>Latin</tt>) in which the constant's text should be expressed. If the
3011: alphabet name is absent, the Latin alphabet is used. When the alphabet name
3012: is present, only the first letter of the alphabet name is interpreted. Thus,
3013: the words <tt>Greek</tt> and <tt>Grec</tt> designate the same alphabet. In
1.30 cvs 3014: current versions of Thot, only the Greek and Latin alphabets are
3015: available.</p>
1.18 cvs 3016: <pre> 'CONST' ConstSeq
1.30 cvs 3017: ConstSeq = Const < Const > .
1.1 cvs 3018: Const = ConstID '=' ConstType ConstValue ';' .
3019: ConstID = NAME .
3020: ConstType ='Text' [ Alphabet ] / 'Symbol' /
3021: 'Graphics' / 'Picture' .
3022: ConstValue = STRING .
1.18 cvs 3023: Alphabet = NAME .</pre>
1.30 cvs 3024:
3025: <p>For character strings in the Latin alphabet (ISO Latin-1 character set),
1.1 cvs 3026: characters having codes higher than 127 (decimal) are represented by their
1.18 cvs 3027: code in octal.</p>
1.30 cvs 3028:
3029: <p>In the case of a symbol or graphical element, the value only contains a
1.37 cvs 3030: single character, between apostrophes, which indicates the form of the
3031: element which must be drawn in the box whose content is the constant. The
3032: symbol or graphical element takes the dimensions of the box, which are
3033: determined by the <tt>Height</tt> and <tt>Width</tt> rules. See <a
3034: href="#sectb72">table of codes</a> for the symbols and graphical elements.</p>
1.30 cvs 3035:
1.18 cvs 3036: <blockquote class="example">
1.30 cvs 3037: <p><strong>Example:</strong></p>
3038:
3039: <p>The constants ``Summary:'' and fraction bar, which were described
3040: earlier, are declared:</p>
3041: <pre>CONST
1.1 cvs 3042: SummaryConst = Text 'Summary:';
1.18 cvs 3043: Bar = Graphics 'h';</pre>
3044: </blockquote>
3045: </div>
1.1 cvs 3046:
1.18 cvs 3047: <div class="subsection">
1.37 cvs 3048: <h3><a name="sectc426" id="sectc426">Variables</a></h3>
1.1 cvs 3049:
1.37 cvs 3050: <p>Variables permit the definition of computed content for presentation
3051: boxes. A variable is associated with a presentation box by a <tt>Content</tt>
3052: rule; but before being used in a <tt>Content</tt> rule, a variable can be
3053: defined in the <tt>VAR</tt> section. It is also possible to define a variable
3054: at the time of its use in a <tt>Content</tt> rule, as can be done with a
1.30 cvs 3055: constant.</p>
3056:
3057: <p>A variable has a name and a value which is a character string resulting
1.37 cvs 3058: from the concatenation of the values of a sequence of functions. Each
1.30 cvs 3059: variable declaration is composed of the variable name followed by a colon and
1.37 cvs 3060: the sequence of functions which produces its value, separated by spaces. Each
1.18 cvs 3061: declaration is terminated by a semi-colon.</p>
3062: <pre> 'VAR' VarSeq
1.30 cvs 3063: VarSeq = Variable < Variable > .
1.1 cvs 3064: Variable = VarID ':' FunctionSeq ';' .
3065: VarID = NAME .
1.30 cvs 3066: FunctionSeq = Function < Function > .</pre>
3067:
1.37 cvs 3068: <p>Several functions are available. The first two return, in the form of a
3069: character string, the current date. <tt>DATE</tt> returns the date in
1.18 cvs 3070: English, while <tt>FDATE</tt> returns the date in french.</p>
1.30 cvs 3071:
3072: <p>Two other functions, <tt>DocName</tt> and <tt>DirName</tt>, return the
1.18 cvs 3073: document name and the directory where the document is stored.</p>
1.30 cvs 3074:
1.38 ! cvs 3075: <p>Function <tt>ElemName</tt> returns the name of the element which created
1.30 cvs 3076: the presentation box whose contents are the variable.</p>
3077:
1.38 ! cvs 3078: <p>Function <tt>AttributeName</tt> returns the name of the attribute which
! 3079: created the presentation box whose contents are the variable. The
! 3080: presentation box must be created by an attribute.</p>
! 3081:
! 3082: <p>Function <tt>AttributeValue</tt> returns the value of the attribute which
! 3083: created the presentation box whose contents are the variable. The
! 3084: presentation box must be created by an attribute.</p>
! 3085:
1.30 cvs 3086: <p>Another function simply returns the value of a presentation constant. For
3087: any constant declared in the <tt>CONST</tt> section, it is sufficient to give
1.37 cvs 3088: the name of the constant. Otherwise, the type and value of the constant must
1.30 cvs 3089: be given, using the same form as in a <a href="#sectc425">constant
1.18 cvs 3090: declaration</a>. If the constant is not of type text, (types <tt>Symbol</tt>,
3091: <tt>Graphics</tt> or <tt>Picture</tt>), it must be alone in the variable
3092: definition; only constants of type <tt>Text</tt> can be mixed with other
3093: functions.</p>
1.30 cvs 3094:
3095: <p>It is also possible to obtain the value of an attribute, simply by
1.37 cvs 3096: mentioning the attribute's name. The value of this function is the value of
1.30 cvs 3097: the attribute for the element which created the presentation box whose
1.37 cvs 3098: contents are the variable. If the creating element does not have the
3099: indicated attribute, the value is an empty string. In the case of a numeric
1.30 cvs 3100: attribute, the attribute is translated into a decimal number in arabic
1.37 cvs 3101: numerals. If another form is desired, the <tt>VALUE</tt> function must be
1.30 cvs 3102: used.</p>
3103:
3104: <p>The last available function returns, as a character string, the value of a
1.1 cvs 3105: counter, an attribute or a page number. This value can be presented in
1.37 cvs 3106: different styles. The keyword <tt>VALUE</tt> is followed (between
1.1 cvs 3107: parentheses) by the name of the counter, the name of the attribute, or the
1.18 cvs 3108: keyword <tt>PageNumber</tt> and the desired style, the two parameters being
1.37 cvs 3109: separated by a comma. The style is a keyword which indicates whether the
1.18 cvs 3110: value should be presented in arabic numerals (<tt>Arabic</tt>), lower-case
3111: roman numerals (<tt>LRoman</tt>), or upper-case roman numerals
3112: (<tt>URoman</tt>), or by an upper-case letter (<tt>Uppercase</tt>) or
3113: lower-case letter (<tt>Lowercase</tt>).</p>
1.30 cvs 3114:
3115: <p>For a page counter, the keyword <tt>PageNumber</tt> can be followed,
3116: between parentheses, by the name of the view from which to obtain the page
1.37 cvs 3117: number. By default, the first view declared in the <tt>VIEWS</tt> section is
3118: used. The value obtained is the number of the page on which is found the
1.30 cvs 3119: element that is using the variable in a <tt>Content</tt> rule.</p>
3120:
3121: <p>For an ordinary counter, the name of the counter can be preceded by the
1.37 cvs 3122: keyword <tt>MaxRangeVal</tt> or <tt>MinRangeVal</tt>. These keywords mean
1.1 cvs 3123: that the value returned by the function is the maximum (minimum resp.) value
3124: taken by the counter in the whole document, not the value for the element
1.18 cvs 3125: concerned by the function.</p>
3126: <pre> Function = 'DATE' / 'FDATE' /
1.1 cvs 3127: 'DocName' / 'DirName' /
1.38 ! cvs 3128: 'ElemName' / 'AttributeName' / 'AttributeValue' /
1.1 cvs 3129: ConstID / ConstType ConstValue /
3130: AttrID /
3131: 'VALUE' '(' PageAttrCtr ','
3132: CounterStyle ')' .
1.6 cvs 3133: PageAttrCtr = 'PageNumber' [ '(' ViewID ')' ] /
1.1 cvs 3134: [ MinMax ] CounterID / AttrID .
3135: CounterStyle = 'Arabic' / 'LRoman' / 'URoman' /
3136: 'Uppercase' / 'Lowercase' .
1.18 cvs 3137: MinMax = 'MaxRangeVal' / 'MinRangeVal' .</pre>
1.30 cvs 3138:
1.18 cvs 3139: <blockquote class="example">
1.30 cvs 3140: <p><strong>Example:</strong></p>
3141:
3142: <p>To make today's date appear at the top of the first page of a report, a
3143: <a href="#sectc4232"><tt>CREATE</tt> rule</a> associated with the
3144: Report_Title element type generates a presentation box whose content
3145: (specified by the <tt>Content</tt> rule of that presentation box) is the
3146: variable:</p>
3147: <pre>VAR
1.18 cvs 3148: Todays_date : TEXT 'Version of ' DATE;</pre>
1.30 cvs 3149:
3150: <p>To produce, before each section title, the chapter number (in upper-case
3151: roman numerals) followed by the section number (in arabic numerals), two
3152: counters must be defined:</p>
3153: <pre>COUNTERS
1.1 cvs 3154: ChapterCtr : RANK OF Chapter;
1.18 cvs 3155: SectionCtr : RANK OF Section;</pre>
1.30 cvs 3156:
3157: <p>and the Section_Title element must create a presentation box whose
3158: content is the variable</p>
3159: <pre>VAR
1.1 cvs 3160: SectionNum : VALUE (ChapterCtr, URoman) TEXT '-'
1.18 cvs 3161: VALUE (SectionCtr, Arabic);</pre>
1.30 cvs 3162:
3163: <p>In order to make the page number on which each section begins appear in
3164: the table of contents view next to the section title, each Section_Title
3165: element must create a presentation box, visible only in the table of
3166: contents view, whose content is the variable:</p>
3167: <pre>VAR
1.1 cvs 3168: TitlePageNume :
1.18 cvs 3169: VALUE (PageNumber(Full_text), Arabic);</pre>
3170: </blockquote>
3171: </div>
1.1 cvs 3172:
1.18 cvs 3173: <div class="subsection">
1.37 cvs 3174: <h3><a name="sectc427" id="sectc427">Default presentation rules</a></h3>
1.1 cvs 3175:
1.30 cvs 3176: <p>In order to avoid having to specify, for each element type defined in the
1.1 cvs 3177: structure schema, values for every one of the numerous presentation
1.34 cvs 3178: properties, the presentation schema allows the definition of a set of default
1.37 cvs 3179: presentation rules. These rules apply to all the boxes of the elements
1.1 cvs 3180: defined in the structure schema and to the presentation boxes and page layout
1.37 cvs 3181: boxes defined in the presentation schema. Only rules which differ from these
1.18 cvs 3182: default need to be specified in other sections of the presentation schema.</p>
1.30 cvs 3183:
3184: <p>For the primary view, the default rules can define every presentation
1.34 cvs 3185: property, but not the <a href="#presfunct">presentation functions</a> or the
1.18 cvs 3186: <a href="#sectc4223">linebreaking conditions</a> (the <tt>NoBreak1</tt>,
3187: <tt>NoBreak2</tt>, and <tt>Gather</tt> rules).</p>
1.30 cvs 3188:
3189: <p>In a presentation schema, the default presentation rules section is
3190: optional; in this case, the <tt>DEFAULT</tt> keyword is also absent and the
3191: following rules are considered to be the default rules:</p>
1.26 cvs 3192: <pre> Visibility: Enclosing =;
3193: VertRef: * . Left;
3194: HorizRef: Enclosed . HRef;
3195: Height: Enclosed . Height;
3196: Width: Enclosed . Width;
3197: VertPos: Top = Previous . Bottom;
3198: HorizPos: Left = Enclosing . Left;
3199: MarginTop: 0;
3200: MarginRight: 0;
3201: MarginBottom: 0;
3202: MarginLeft: 0;
3203: PaddingTop: 0;
3204: PaddingRight: 0;
3205: PaddingBottom: 0;
3206: PaddingLeft: 0;
3207: BorderTopWidth: 0;
3208: BorderRightWidth: 0;
3209: BorderBottomWidth: 0;
3210: BorderLeftWidth: 0;
3211: BorderTopColor: Foreground;
3212: BorderRightColor: Foreground;
3213: BorderBottomColor: Foreground;
3214: BorderLeftColor: Foreground;
3215: BorderTopStyle: None;
3216: BorderRightStyle: None;
3217: BorderBottomStyle: None;
3218: BorderLeftStyle: None;
3219: VertOverflow: No;
3220: HorizOverflow: No;
3221: Size: Enclosing =;
3222: Style: Enclosing =;
3223: Weight: Enclosing =;
3224: Font: Enclosing =;
3225: Underline: Enclosing =;
3226: Thickness: Enclosing =;
3227: Indent: Enclosing =;
3228: LineSpacing: Enclosing =;
3229: Adjust: Enclosing =;
3230: Hyphenate: Enclosing =;
3231: PageBreak: Yes;
3232: LineBreak: Yes;
3233: InLine: Yes;
3234: Depth: 0;
3235: LineStyle: Enclosing =;
3236: LineWeight: Enclosing =;
3237: FillPattern: Enclosing =;
3238: Background: Enclosing =;
3239: Foreground: Enclosing =;</pre>
1.30 cvs 3240:
3241: <p>If other values are desired for the default rules, they must be defined
1.37 cvs 3242: explicitly in the default rules section. In fact, it is only necessary to
1.1 cvs 3243: define those default rules which differ from the ones above, since the rules
1.18 cvs 3244: above will be used whenever a rule is not explicitly named.</p>
1.30 cvs 3245:
1.37 cvs 3246: <p>Default rules for views other than the primary view can also be specified.
1.1 cvs 3247: Otherwise, the default rules for the primary views are applied to the other
1.18 cvs 3248: views.</p>
1.30 cvs 3249:
3250: <p>Default rules are expressed in the same way as <a
3251: href="#sectc4215">explicit rules for document elements</a>.</p>
1.18 cvs 3252: </div>
1.1 cvs 3253:
1.18 cvs 3254: <div class="subsection">
1.37 cvs 3255: <h3><a name="sectc428" id="sectc428">Presentation and page layout
3256: boxes</a></h3>
1.1 cvs 3257:
1.30 cvs 3258: <p>The presentation process uses elements which are not part of the logical
1.1 cvs 3259: structure of the document, such as pages (which are the page layout boxes) or
3260: alternatively, rules, numbers, or words introducing certain parts of the
3261: document, such as ``Summary'', ``Appendices'', ``Bibliography'', etc. (which
1.18 cvs 3262: are presentation boxes).</p>
1.30 cvs 3263:
3264: <p>After the word <tt>BOXES</tt>, each presentation or page layout box is
3265: defined by its name and a sequence of presentation rules which indicate how
1.37 cvs 3266: they must be displayed. These rules are the same as those which define the
3267: boxes associated with element of the logical structure of the document, with
3268: a single exception, the <a href="#sectc4231"><tt>Content</tt> rule</a> which
3269: is used only to specify the content of presentation boxes. The content of
3270: boxes associated with elements of the document structure is defined in each
3271: document or object and thus is not specified in the presentation schema,
3272: which applies to all documents or objects of a class.</p>
1.30 cvs 3273:
3274: <p>Among the rules which define a presentation box, certain ones can refer to
1.37 cvs 3275: another presentation box (for example, in their positional rules). If the
1.1 cvs 3276: designated box is defined after the box which designates it, a
1.18 cvs 3277: <tt>FORWARD</tt> instruction followed by the name of the designated box must
3278: appear before the designation.</p>
3279: <pre> 'BOXES' BoxSeq
1.30 cvs 3280: BoxSeq = Box < Box > .
1.1 cvs 3281: Box ='FORWARD' BoxID ';' /
3282: BoxID ':' ViewRuleSeq .
1.18 cvs 3283: BoxID = NAME .</pre>
3284: </div>
1.1 cvs 3285:
1.18 cvs 3286: <div class="subsection">
1.37 cvs 3287: <h3><a name="sectc429" id="sectc429">Presentation of structured
3288: elements</a></h3>
1.1 cvs 3289:
1.30 cvs 3290: <p>After the words <tt>RULES</tt>, the presentation schema gives the
3291: presentation rules that apply to the elements whose types are defined in the
1.37 cvs 3292: structure schema. Only those rules which differ from the <a
1.18 cvs 3293: href="#sectc427">default</a> must be specified in the <tt>RULES</tt>
3294: section.</p>
1.30 cvs 3295:
3296: <p>The rule definitions for each element type are composed of the name of the
1.1 cvs 3297: element type (as specified in the structure schema) followed by a colon and
1.18 cvs 3298: the set of rules specific to that type.</p>
1.30 cvs 3299:
3300: <p>The type name can be preceded by a star in the special case where the
1.18 cvs 3301: structure schema defines an <a href="#sectd3284">inclusion</a> without
1.1 cvs 3302: expansion (or with partial expansion) of a type with the same name as an
1.18 cvs 3303: element of defined in the structure schema.</p>
1.30 cvs 3304:
3305: <p>In the case where the element is a <a href="#sectd3285">mark pair</a>, but
1.18 cvs 3306: only in this case, the type name can be preceded by the keywords
1.37 cvs 3307: <tt>First</tt> or <tt>Second</tt>. These keywords indicate whether the rules
1.18 cvs 3308: that follow apply to the first or second mark of the pair.</p>
3309: <pre> 'RULES' PresentSeq
1.30 cvs 3310: PresentSeq = Present < Present > .
1.6 cvs 3311: Present = [ '*' ] [ FirstSec ] ElemID ':'
3312: ViewRuleSeq .
1.18 cvs 3313: FirstSec = 'First' / 'Second' .</pre>
1.30 cvs 3314:
3315: <p>A presentation schema can define presentation rules for base elements,
1.37 cvs 3316: which are defined implicitly in the structure schemas. In the English version
1.30 cvs 3317: of the presentation schema compiler, the base type names are the same as in
3318: the S language, but they are terminated by the <tt>_UNIT</tt> suffix:
1.18 cvs 3319: <tt>TEXT_UNIT</tt>, <tt>PICTURE_UNIT</tt>, <tt>SYMBOL_UNIT</tt>,
1.37 cvs 3320: <tt>GRAPHICS_UNIT</tt>. The base type names are written in upper-case
1.18 cvs 3321: letters.</p>
3322: </div>
3323:
3324: <div class="subsection">
1.37 cvs 3325: <h3><a name="sectc4210" id="sectc4210">Logical attribute presentation</a></h3>
1.18 cvs 3326:
1.30 cvs 3327: <p>After the keyword <tt>ATTRIBUTES</tt>, all attributes which are to have
1.37 cvs 3328: some effect on the presentation of the element to which they are attached
3329: must be mentioned, along with the corresponding presentation rules. This is
3330: true for both global attributes (which can be attached to all element types)
3331: and local attributes (which can only be attached to certain element
3332: types).</p>
1.30 cvs 3333:
3334: <p>Also mentioned in this section are attributes which imply an effect on
1.1 cvs 3335: elements in the subtree of the element to which they are attached. The
1.37 cvs 3336: presentation of these descendants can be modified as a function of the value
1.1 cvs 3337: of the attribute which they inherit, just as if it was attached to them
1.18 cvs 3338: directly.</p>
1.30 cvs 3339:
3340: <p>The specification for each attribute includes the attribute's name,
3341: followed by an optional value specification and, after a colon, a set of
1.37 cvs 3342: rules. The set of rules must contain at least one rule.</p>
1.30 cvs 3343:
1.37 cvs 3344: <p>When there is no value specification, the rules are applied to all
3345: elements which carry the attribute, no matter what their value. When the
3346: rules must only apply when the attribute has certain values, these values
3347: must be specified. Thus, the same attribute can appear in the
3348: <tt>ATTRIBUTES</tt> section several times, with each appearance having a
3349: different value specification. However, reference attributes never have a
3350: value specification and, as a result, can only appear once in the
3351: <tt>ATTRIBUTES</tt> section.</p>
1.30 cvs 3352:
3353: <p>To specify that the presentation rules apply to some of the descendants of
3354: the element having the attribute, the name of the affected element type is
1.37 cvs 3355: given, between parentheses, after the attribute name. This way, the
3356: presentation rules for the attribute will be applied to the element having
3357: the attribute, if it is of the given type, and to all of its descendants of
3358: the given type. In the case where this type is a <a href="#sectd3285">mark
3359: pair</a>, but only in this case, the type name can be preceded by the
3360: keywords <tt>First</tt> or <tt>Second</tt>. These keywords indicate whether
3361: the rules that follow apply to the first or second mark of the pair. If the
3362: rule must apply to several different element types, the specification must be
3363: repeated for each element type.</p>
1.30 cvs 3364:
3365: <p>The specification of values for which the presentation rules will be
3366: applied varies according to the type of the attribute:</p>
1.18 cvs 3367: <dl>
1.30 cvs 3368: <dt>numeric attribute</dt>
3369: <dd>If the rules are to apply for one value of the attribute, then the
1.37 cvs 3370: attribute name is followed by an equals sign and this value. If the
1.30 cvs 3371: rules are to apply for all values less than (or greater than) a
3372: threshold value, non-inclusive, the attribute name followed by a '<'
1.37 cvs 3373: sign (or a '>' sign, respectively) and the threshold value. If the
3374: rules must apply to a range of values, the attribute name is followed
3375: by the word '<tt>IN</tt>' and the two bounds of the range, enclosed in
3376: brackets and separated by two periods ('<tt>..</tt>'). In the case of
3377: ranges, the values of the bounds are included in the range.
1.30 cvs 3378: <p>The threshold value in the comparisons can be the value of an
1.37 cvs 3379: attribute attached to an ancestor element. In this case, the attribute
1.30 cvs 3380: name is given instead of a constant value.</p>
1.37 cvs 3381: <p>It is also possible to write rules which apply only when a
3382: comparison between two different attributes of the element's ancestors
3383: is true. In this case, the first attribute name is followed by a
3384: comparison keyword and the name of the second attribute. The comparison
3385: keywords are <tt>EQUAL</tt> (simple equality), <tt>LESS</tt>
3386: (non-inclusive less than), and <tt>GREATER</tt> (non-inclusive greater
3387: than).</p>
1.30 cvs 3388: </dd>
3389: <dt>text attribute</dt>
3390: <dd>If the rules are to apply for one value of the attribute, then the
3391: attribute name is followed by an equals sign and this value.</dd>
3392: <dt>reference attribute</dt>
3393: <dd>There is never a value specification; the rules apply no matter what
3394: element is designated by the attribute.</dd>
3395: <dt>enumerated attribute</dt>
3396: <dd>If the rules are to apply for one value of the attribute, then the
3397: attribute name is followed by an equals sign and this value.</dd>
1.18 cvs 3398: </dl>
1.30 cvs 3399:
3400: <p>The order in which the rules associated with a numeric attribute are
1.37 cvs 3401: defined is important. When multiple sets of rules can be applied, the first
1.30 cvs 3402: set declared is the one used.</p>
3403:
3404: <p>Rules for attributes have priority over both default rules and rules
1.37 cvs 3405: associated with element types. The attribute rules apply to the element to
3406: which the attribute is attached. It is the rules which apply to the
1.1 cvs 3407: surrounding elements (and especially to the descendants) which determine the
3408: effect of the attribute rules on the environment ( and especially on the
1.18 cvs 3409: terminal elements of the structure).</p>
3410: <pre> 'ATTRIBUTES' PresAttrSeq
1.30 cvs 3411: PresAttrSeq = PresAttr < PresAttr > .
1.1 cvs 3412: PresAttr = AttrID [ '(' [ FirstSec ] ElemID ')' ]
3413: [ AttrRelation ] ':' ViewRuleSeq .
3414: AttrID = NAME .
3415: AttrRelation ='=' AttrVal /
1.30 cvs 3416: '>' [ '-' ] MinValue /
1.1 cvs 3417: '<' [ '-' ] MaxValue /
3418: 'IN' '[' [ '-' ] LowerBound '..'
3419: [ '-' ] UpperBound ']' /
3420: 'GREATER' AttrID /
3421: 'EQUAL' AttrID /
3422: 'LESS' AttrID .
3423: AttrVal = [ '-' ] EqualNum / EqualText /
3424: AttrValue .
3425: MinValue = NUMBER .
3426: MaxValue = NUMBER .
3427: LowerBound = NUMBER .
3428: UpperBound = NUMBER.
3429: EqualNum = NUMBER .
3430: EqualText = STRING .
1.18 cvs 3431: AttrValue = NAME .</pre>
1.30 cvs 3432:
1.37 cvs 3433: <p>In presentation rules associated with a numeric attribute (and only in
3434: such rules), the attribute name can be used in place of a numeric value. In
3435: this case, the value of the attribute is used in the application of the rule.
3436: Thus, the attribute can represent a relation between the size of two boxes,
3437: the height and width of a box, the height of an area where page breaks are
3438: prohibited, the distance between two boxes, the position of the reference
3439: axis of a box, the interline spacing, the indentation of the first line, the
1.18 cvs 3440: visibility, the depth (z-order), or the character set.</p>
1.30 cvs 3441:
1.37 cvs 3442: <p>The presentation rules associated with reference attributes, it is
3443: possible to use the element designated by the attribute as a reference box in
3444: a positional or extent rule. This element is represented in the <a
1.18 cvs 3445: href="#sectc4218">position</a> or <a href="#sectc4219">extent</a> rule by the
3446: keyword <tt>Referred</tt>.</p>
1.30 cvs 3447:
1.18 cvs 3448: <blockquote class="example">
1.30 cvs 3449: <p><strong>Example:</strong></p>
3450:
1.37 cvs 3451: <p>In all structure schemas, there is a global Language attribute defined
3452: as follows:</p>
1.30 cvs 3453: <pre>ATTR
1.18 cvs 3454: Language = TEXT;</pre>
1.30 cvs 3455:
3456: <p>The following rules would make French text be displayed in roman
3457: characters and English text be displayed in italics:</p>
3458: <pre>ATTRIBUTES
1.1 cvs 3459: Language = 'French' :
1.6 cvs 3460: Style : Roman;
1.1 cvs 3461: Language = 'English' :
1.18 cvs 3462: Style : Italics;</pre>
1.30 cvs 3463:
3464: <p>Using these rules, when the user puts the Language attribute with the
3465: value 'English' on the summary of a document, every character string
1.37 cvs 3466: (terminal elements) contained in the summary are displayed in italics. See
1.30 cvs 3467: the <a href="#sectd42252"><tt>Style</tt> rule</a>.</p>
1.18 cvs 3468: </blockquote>
1.30 cvs 3469:
1.18 cvs 3470: <blockquote class="example">
1.30 cvs 3471: <p><strong>Example:</strong></p>
3472:
3473: <p>A numeric attribute representing the importance of the part of the
3474: document to which it is attached can be defined:</p>
3475: <pre>ATTR
1.18 cvs 3476: Importance = INTEGER;</pre>
1.30 cvs 3477:
3478: <p>In the presentation schema, the importance of an element is reflected in
3479: the choice of character size, using the following rules.</p>
3480: <pre>ATTRIBUTES
1.1 cvs 3481: Importance < 2 :
3482: Size : 1;
3483: Importance IN [2..4] :
3484: Size : Importance;
3485: Importance = 10 :
3486: Size : 5;
1.30 cvs 3487: Importance > 4 :
1.18 cvs 3488: Size : 4;</pre>
1.30 cvs 3489:
3490: <p>Thus, the character size corresponds to the value of the Importance
3491: attribute; its value is</p>
3492: <ul>
3493: <li>the value of the Importance attribute when the value is between 2 and
3494: 4 (inclusive),</li>
3495: <li>1, when the value of the Importance attribute is less than 2,</li>
3496: <li>4, when the value of the Importance attribute is greater than 4,</li>
3497: <li>5, when the value of the Importance attribute is 10.</li>
3498: </ul>
3499:
1.37 cvs 3500: <p>The last case (value 5) must be defined before the case which handles
3501: all Importance values greater than 4, because the two rules are not
3502: disjoint and the first one defined will have priority. Otherwise, when the
3503: Importance attribute has value 10, the font size will be 4.</p>
1.18 cvs 3504: </blockquote>
1.30 cvs 3505:
1.18 cvs 3506: <blockquote class="example">
1.30 cvs 3507: <p><strong>Example:</strong></p>
3508:
3509: <p>Suppose the structure defines a list element which can have an attribute
3510: defining the type of list (numbered or not):</p>
3511: <pre>STRUCT
1.1 cvs 3512: list (ATTR list_type = enumeration, dash)
1.18 cvs 3513: = LIST OF (list_item = TEXT);</pre>
1.30 cvs 3514:
3515: <p>Then, the presentation schema could use the attribute placed on the list
3516: element to put either a dash or a number before the each element of the
3517: list:</p>
3518: <pre>ATTRIBUTES
1.1 cvs 3519: list_type (list_item) = enumeration :
3520: CreateBefore (NumberBox);
3521: list_type (list_item) = dash :
1.18 cvs 3522: CreateBefore (DashBox);</pre>
3523: </blockquote>
1.30 cvs 3524:
1.18 cvs 3525: <blockquote class="example">
1.30 cvs 3526: <p><strong>Example:</strong></p>
3527:
1.37 cvs 3528: <p>Suppose that two attributes are defined in the structure schema. The
3529: first is a numeric global attribute called ``version''. The other is a
1.30 cvs 3530: local attribute defined on the root of the document called
3531: ``Document_version'':</p>
3532: <pre>STRUCTURE Document
1.1 cvs 3533: ATTR
3534: version = INTEGER;
3535: STRUCT
3536: Document (ATTR Document_version = INTEGER) =
3537: BEGIN
3538: SomeElement ;
3539: ...
3540: SomeOtherElement ;
3541: END ;
1.18 cvs 3542: ...</pre>
1.30 cvs 3543:
3544: <p>These attributes can be used in the presentation schema to place change
3545: bars in the margin next to elements whose version attribute has a value
3546: equal to the Document_version attribute of the root and to place a star in
3547: margin of elements whose version attribute is less than the value of the
3548: root's Document_version attribute:</p>
3549: <pre>ATTRIBUTES
1.1 cvs 3550: version EQUAL Document_version :
3551: CreateBefore (ChangeBarBox) ;
3552: version LESS Document_version :
1.18 cvs 3553: CreateBefore (StarBox) ;</pre>
3554: </blockquote>
3555: </div>
1.1 cvs 3556:
1.18 cvs 3557: <div class="subsection">
1.37 cvs 3558: <h3><a name="sectc4212" id="sectc4212">Value transmission rules</a></h3>
1.1 cvs 3559:
1.30 cvs 3560: <p>The last section of a presentation schema, which is optional, serves to
1.1 cvs 3561: defines the way in which a document transmits certain values to its
1.37 cvs 3562: sub-documents. A sub-document is an document <a
1.18 cvs 3563: href="#inclusion">included</a> without expansion or with partial expansion.
1.1 cvs 3564: The primary document can transmit to its sub-documents the values of certain
3565: counters or the textual content of certain of its elements, as a function of
1.18 cvs 3566: their type.</p>
1.30 cvs 3567:
3568: <p>The sub-documents receive these values in attributes which must be defined
1.37 cvs 3569: in their structure schema as local attributes of the root element. The types
1.30 cvs 3570: of these attributes must correspond to the type of the value which they
3571: receive: numeric attributes for receiving the value of a counter, textual
3572: attributes for receiving the content of an element.</p>
3573:
3574: <p>In the structure schema of the primary document, there appears at the end,
1.37 cvs 3575: after the <tt>TRANSMIT</tt> keyword, a sequence of transmission rules. Each
1.1 cvs 3576: rule begins with the name of the counter to transmit or of the element type
1.37 cvs 3577: whose textual content will be transmitted. This name is followed by the
3578: keyword <tt>To</tt> and the name of the attribute of the sub-document to
3579: which the value is transmitted. The sub-document class is indicated between
3580: parentheses after the name of the attribute. The transmission rule ends with
1.18 cvs 3581: a semicolon.</p>
1.30 cvs 3582: <pre> TransmitSeq = Transmit < Transmit > .
1.1 cvs 3583: Transmit = TypeOrCounter 'To' ExternAttr
3584: '(' ElemID ')' ';' .
3585: TypeOrCounter = CounterID / ElemID .
1.18 cvs 3586: ExternAttr = NAME .</pre>
1.30 cvs 3587:
1.18 cvs 3588: <blockquote class="example">
1.30 cvs 3589: <p><strong>Example:</strong></p>
3590:
3591: <p>Consider a Book document class which includes instances of the Chapter
1.37 cvs 3592: document class. These classes might have the following schemas:</p>
1.30 cvs 3593: <pre>STRUCTURE Book
1.1 cvs 3594: STRUCT
3595: Book = BEGIN
3596: Title = Text;
3597: Body = LIST OF (Chapter INCLUDED);
3598: END;
3599: ...
3600:
3601: STRUCTURE Chapter
3602: STRUCT
3603: Chapter (ATTR FirstPageNum = Integer;
3604: ChapterNum = Integer;
3605: CurrentTitle = Text) =
1.6 cvs 3606: BEGIN
3607: ChapterTitle = Text;
3608: ...
3609: END;
1.18 cvs 3610: ...</pre>
1.30 cvs 3611:
3612: <p>Then the presentation schema for books could define chapter and page
3613: counters. The following transmission rules in the book presentation schema
3614: would transmit values for the three attributes defined at the root of each
3615: chapter sub-document.</p>
3616: <pre>PRESENTATION Book;
1.1 cvs 3617: VIEWS
3618: Full_text;
3619: COUNTERS
3620: ChapterCtr: Rank of Chapter;
3621: PageCtr: Rank of Page(Full_text);
3622: ...
3623: TRANSMIT
3624: PageCtr TO FirstPageNum(Chapter);
3625: ChapterCtr TO ChapterNum(Chapter);
3626: Title TO CurrentTitle(Chapter);
1.18 cvs 3627: END</pre>
1.30 cvs 3628:
3629: <p>Thus, each chapter included in a book can number its pages as a function
3630: of the number of pages preceding it in the book, can make the chapter's
3631: number appear before the number of each of its sections, or can place the
3632: title of the book at the top of each page.</p>
1.18 cvs 3633: </blockquote>
3634: </div>
1.1 cvs 3635:
1.18 cvs 3636: <div class="subsection">
1.37 cvs 3637: <h3><a name="sectc4213" id="sectc4213">Presentation rules</a></h3>
1.1 cvs 3638:
1.30 cvs 3639: <p>Whether defining the appearance of a presentation or page layout box, an
1.1 cvs 3640: element type, or an attribute value, the set of presentation rules that apply
1.18 cvs 3641: is always defined in the same way.</p>
1.30 cvs 3642:
3643: <p>Normally, a set of presentation rules is placed between the keywords
1.18 cvs 3644: <tt>BEGIN</tt> and <tt>END</tt>, the keyword <tt>END</tt> being followed by a
1.37 cvs 3645: semicolon. The first section of this block defines the rules that apply to
1.18 cvs 3646: the primary view, if the <a href="#sectc427">default rules</a> are not
1.37 cvs 3647: completely suitable. Next comes the rules which apply to specific other
1.1 cvs 3648: views, with a rule sequence for each view for which the default rules are not
1.37 cvs 3649: satisfactory. If the default rules are suitable for the non-primary views,
3650: there will not be any specific rules for these views. If there is only one
1.18 cvs 3651: rule which applies to all views then the keywords <tt>BEGIN</tt> and
3652: <tt>END</tt> need not appear.</p>
1.30 cvs 3653:
3654: <p>For each view, it is only necessary to specify those rules which differ
3655: from the default rules for the view, so that for certain views (or even all
3656: views), there may be no specific rules.</p>
3657:
3658: <p>The specific rules for a non-primary view are introduced by the <a
1.37 cvs 3659: name="inkeyword" id="inkeyword"><tt>IN</tt> keyword</a>, followed by the view
3660: name. The rules for that view follow, delimited by the keywords
3661: <tt>BEGIN</tt> and <tt>END</tt>, or without these two keywords when there is
3662: only one rule.</p>
1.30 cvs 3663:
3664: <p><strong>Note:</strong> the view name which follows the <tt>IN</tt> keyword
1.1 cvs 3665: must not be the name of the primary view, since the rules for that view are
1.18 cvs 3666: found before the rules for the other views.</p>
1.30 cvs 3667:
3668: <p>Within each block concerning a view, other blocks can appear, delimited by
1.37 cvs 3669: the same keywords <tt>BEGIN</tt> and <tt>END</tt>. Each of these blocks
3670: gathers the presentation rules that apply, for a given view, only when a
3671: given condition is satisfied. Each block is preceded by a condition
3672: introduced by the <tt>IF</tt> keyword. If such a conditional block contains
3673: only one rule, the keywords <tt>BEGIN</tt> and <tt>END</tt> can be
3674: omitted.</p>
3675:
3676: <p>Although the syntax allows any presentation rule to appear in a
3677: conditional block, only <a href="#sectc4232">creation rules</a> are allowed
3678: after any condition; other rules are allowed only after conditions
3679: <tt>Within</tt> and ElemID. In addition, the following rules cannot be
3680: conditional: <tt>PageBreak, LineBreak, Inline, Gather</tt>.</p>
1.30 cvs 3681:
3682: <p>For a given view, the rules that apply without any condition must appear
1.37 cvs 3683: before the first conditional block. If some rules apply only when none of the
3684: specified condition holds, they are grouped in a block preceded by the
3685: keyword <tt>Otherwise</tt>, and that block must appear after the last
3686: conditionnal block concerning the same view.</p>
1.30 cvs 3687: <pre> ViewRuleSeq = 'BEGIN' < RulesAndCond > < ViewRules >
1.1 cvs 3688: 'END' ';' /
3689: ViewRules / CondRules / Rule .
3690: RulesAndCond = CondRules / Rule .
3691: ViewRules = 'IN' ViewID CondRuleSeq .
1.30 cvs 3692: CondRuleSeq = 'BEGIN' < RulesAndCond > 'END' ';' /
1.1 cvs 3693: CondRules / Rule .
1.30 cvs 3694: CondRules = CondRule < CondRule >
1.1 cvs 3695: [ 'Otherwise' RuleSeq ] .
3696: CondRule = 'IF' ConditionSeq RuleSeq .
1.30 cvs 3697: RulesSeq = 'BEGIN' Rule < Rule > 'END' ';' /
1.18 cvs 3698: Rule .</pre>
1.30 cvs 3699:
1.18 cvs 3700: <blockquote class="example">
1.30 cvs 3701: <p><strong>Example:</strong></p>
3702:
3703: <p>The following rules for a report's title make the title visible in the
1.37 cvs 3704: primary view and invisible in the table of contents and in the formula
3705: views (see the <a href="#sectc4224"><tt>Visibility</tt> rule</a>).</p>
1.30 cvs 3706: <pre>Title : BEGIN
1.1 cvs 3707: Visibility : 1;
3708: ... {Other rules for the primary view}
3709: IN Table_of_contents
3710: Visibility : 0;
3711: IN Formulas
3712: Visibility : 0;
1.18 cvs 3713: END;</pre>
3714: </blockquote>
3715: </div>
1.1 cvs 3716:
1.18 cvs 3717: <div class="subsection">
1.37 cvs 3718: <h3><a name="sectc4214" id="sectc4214">Conditions applying to presentation
3719: rules</a></h3>
1.1 cvs 3720:
1.37 cvs 3721: <p>Many conditions can be applied to presentation rules. Conditions allow
3722: certain presentation rules to apply only in certain cases. These conditions
3723: can be based on the structural position of the element. They can be based on
1.1 cvs 3724: whether the element has references, and what type of references, whether the
1.33 cvs 3725: element has attributes, whether the element is empty or not, whether the
3726: element is the root of its document or not. They can also be based on the
3727: value of a counter.</p>
1.30 cvs 3728:
1.37 cvs 3729: <p>It is possible to specify several conditions which must all be true for
3730: the rules to apply.</p>
1.30 cvs 3731:
1.37 cvs 3732: <p>A set of conditions is specified by the <tt>IF</tt> keyword. This keyword
1.30 cvs 3733: is followed by the sequence of conditions, separated by the <tt>AND</tt>
3734: keyword. Each condition is specified by a keyword which defines the condition
3735: type. In some cases, the keyword is followed by other data, which specify the
3736: condition more precisely.</p>
3737:
3738: <p>An elementary condition can be negative; it is then preceded by the
1.18 cvs 3739: <tt>NOT</tt> keyword.</p>
1.30 cvs 3740:
3741: <p>When the presentation rule(s) controlled by the condition apply to a
3742: reference element or a reference attribute, an elementary condition can also
1.37 cvs 3743: apply to element referred by this reference. The <tt>Target</tt> keyword is
3744: used for that purpose. It must appear before the keyword defining the
1.30 cvs 3745: condition type.</p>
1.18 cvs 3746: <pre> CondRule ='IF' ConditionSeq RuleSeq .
1.30 cvs 3747: ConditionSeq = Condition < 'AND' Condition > .
1.1 cvs 3748: Condition = [ 'NOT' ] [ 'Target' ] ConditionElem .
3749: ConditionElem ='First' / 'Last' /
3750: [ 'Immediately' ] 'Within' [ NumParent ]
3751: ElemID [ ExtStruct ] /
3752: ElemID /
3753: 'Referred' / 'FirstRef' / 'LastRef' /
3754: 'ExternalRef' / 'InternalRef' / 'CopyRef' /
3755: 'AnyAttributes' / 'FirstAttr' / 'LastAttr' /
3756: 'UserPage' / 'StartPage' / 'ComputedPage' /
1.33 cvs 3757: 'Empty' / 'Root' /
1.1 cvs 3758: '(' [ MinMax ] CounterName CounterCond ')' /
3759: CondPage '(' CounterID ')' .
3760: NumParent = [ GreaterLess ] NParent .
1.30 cvs 3761: GreaterLess ='>' / '<' .
1.1 cvs 3762: NParent = NUMBER.
1.6 cvs 3763: ExtStruct ='(' ElemID ')' .
1.30 cvs 3764: CounterCond ='<' MaxCtrVal / '>' MinCtrVal /
1.1 cvs 3765: '=' EqCtrVal /
3766: 'IN' '[' ['-'] MinCtrBound '.' '.'
3767: ['-'] MaxCtrBound ']' .
3768: PageCond ='Even' / 'Odd' / 'One' .
3769: MaxCtrVal = NUMBER .
3770: MinCtrVal = NUMBER .
3771: EqCtrVal = NUMBER .
3772: MaxCtrBound = NUMBER .
1.18 cvs 3773: MinCtrBound = NUMBER .</pre>
1.1 cvs 3774:
1.18 cvs 3775: <div class="subsubsection">
1.37 cvs 3776: <h4><a name="sectd42141" id="sectd42141">Conditions based on the logical
3777: position of the element</a></h4>
1.30 cvs 3778:
3779: <p>The condition can be on the position of the element in the document's
1.37 cvs 3780: logical structure tree. It is possible to test whether the element is the
1.30 cvs 3781: first (<tt>First</tt>) or last (<tt>Last</tt>) among its siblings or if it is
3782: not the first (<tt>NOT First</tt>) or not the last (<tt>NOT Last</tt>). These
1.18 cvs 3783: conditions can be associated only with <a href="#sectc4232">creation
3784: rules</a>.</p>
1.30 cvs 3785:
1.33 cvs 3786: <p>It is possible to test if the element is the root of its document (keyword
3787: <code>Root</code>).</p>
3788:
1.30 cvs 3789: <p>It is also possible to test if the element is contained in an element of a
1.18 cvs 3790: given type (<tt>Within</tt>) or if it is not (<tt>NOT Within</tt>). The type
3791: is indicated after the keyword <tt>Within</tt>. If that element type is
1.1 cvs 3792: defined in a structure schema which is not the one which corresponds to the
3793: presentation schema, the type name of this element must be followed, between
1.18 cvs 3794: parentheses, by the name of the structure schema which defines it.</p>
1.30 cvs 3795:
3796: <p>If the keyword <tt>Within</tt> is preceded by <tt>Immediately</tt>, the
1.18 cvs 3797: condition is satisfied only if the <em>parent</em> element has the type
3798: indicated. If the word <tt>Immediately</tt> is missing, the condition is
3799: satisfied if any <em>ancestor</em> has the type indicated.</p>
1.30 cvs 3800:
3801: <p>An integer <i>n</i> can appear between the keyword <tt>Within</tt> and the
1.37 cvs 3802: type. It specifies the number of ancestors of the indicated type that must be
3803: present for the condition to be satisfied. If the keyword
1.18 cvs 3804: <tt>Immediately</tt> is also present, the <i>n</i> immediate ancestors of the
1.37 cvs 3805: element must have the indicated type. The integer <i>n</i> must be positive
3806: or zero. It can be preceded by <tt><</tt> or <tt>></tt> to indicate a
3807: maximum or minimum number of ancestors. If these symbols are missing, the
3808: condition is satisfied only if it exists exactly <i>n</i> ancestors. When
1.30 cvs 3809: this number is missing, it is equivalent to > 0.</p>
3810:
3811: <p>If the condition applies to presentation rules associated with an
3812: attribute, in the <tt>ATTRIBUTES</tt> section of the presentation schema, the
3813: condition can be simply an element name. Presentation rules are then executed
3814: only if the attribute is attached to an element of that type. The keyword
3815: <tt>NOT</tt> before the element name indicates that the presentation rules
3816: must be executed only if the element is not of the type indicated.</p>
1.18 cvs 3817: </div>
1.1 cvs 3818:
1.18 cvs 3819: <div class="subsubsection">
1.37 cvs 3820: <h4><a name="sectd42142" id="sectd42142">Conditions on references</a></h4>
1.30 cvs 3821:
3822: <p>References may be taken into account in conditions, which can be based on
3823: the fact that the element, or one of its ancestors, is designated by a at
3824: least one reference (<tt>Referred</tt>) or by none (<tt>NOT
3825: Referred</tt>).</p>
3826:
3827: <p>If the element or attribute to which the condition is attached is a
3828: reference, the condition can be based on the fact that it acts as the first
3829: reference to the designated element (<tt>FirstRef</tt>), or as the last
3830: (<tt>LastRef</tt>), or as a reference to an element located in another
3831: document (<tt>ExternalRef</tt>) or in the same document
3832: (<tt>InternalRef</tt>).</p>
1.1 cvs 3833:
1.30 cvs 3834: <p>The condition can also be based on the fact that the element is an <a
1.37 cvs 3835: href="#inclusion">inclusion</a>. This is noted (<tt>CopyRef</tt>).</p>
1.30 cvs 3836:
3837: <p>Like all conditions, conditions on references can be inverted by the
1.18 cvs 3838: <tt>NOT</tt> keyword. These conditions can be associated only with <a
3839: href="#sectc4232">creation rules</a>.</p>
3840: </div>
1.1 cvs 3841:
1.18 cvs 3842: <div class="subsubsection">
1.37 cvs 3843: <h4><a name="sectd42143" id="sectd42143">Conditions on logical
3844: attributes</a></h4>
1.30 cvs 3845:
3846: <p>The condition can be based on the presence or absence of attributes
3847: associated with the element, no matter what the attributes or their values.
3848: The <tt>AnyAttributes</tt> keyword expresses this condition.</p>
1.1 cvs 3849:
1.30 cvs 3850: <p>If the condition appears in the presentation rules of an attribute, the
1.37 cvs 3851: <tt>FirstAttr</tt> and <tt>LastAttr</tt> keywords can be used to indicate
3852: that the rules must only be applied if this attribute is the first attribute
3853: for the element or if it is the last (respectively). These conditions can
3854: also be inverted by the <tt>NOT</tt> keyword. These conditions can be
3855: associated only with <a href="#sectc4232">creation rules</a>.</p>
1.30 cvs 3856:
3857: <p>It is also possible to apply certain presentation rules only when the
3858: element being processed or one of its ancestors has a certain attribute,
1.37 cvs 3859: perhaps with a certain value. This can be done in the <a
1.18 cvs 3860: href="#sectc4210"><tt>ATTRIBUTES</tt> section</a>.</p>
3861: </div>
1.1 cvs 3862:
1.18 cvs 3863: <div class="subsubsection">
1.37 cvs 3864: <h4><a name="sectd42144" id="sectd42144">Conditions on page breaks</a></h4>
1.1 cvs 3865:
1.30 cvs 3866: <p>The page break base type (and only this type) can use the following
1.18 cvs 3867: conditions: <tt>ComputedPage</tt>, <tt>StartPage</tt>, and <tt>UserPage</tt>.
3868: The <tt>ComputedPage</tt> condition indicates that the presentation rule(s)
1.37 cvs 3869: should apply if the page break was created automatically by Thot; the
3870: <tt>StartPage</tt> condition is true if the page break is generated before
3871: the element by the <tt>Page</tt> rule; and the <tt>UserPage</tt> condition
3872: applies if the page break was inserted by the user.</p>
1.30 cvs 3873:
3874: <p>These conditions can be associated only with <a href="#sectc4232">creation
1.18 cvs 3875: rules</a>.</p>
3876: </div>
1.1 cvs 3877:
1.18 cvs 3878: <div class="subsubsection">
1.37 cvs 3879: <h4><a name="sectd42145" id="sectd42145">Conditions on the element's
3880: content</a></h4>
1.1 cvs 3881:
1.37 cvs 3882: <p>The condition can be based on whether or not the element is empty. An
1.30 cvs 3883: element which has no children or whose leaves are all empty is considered to
1.37 cvs 3884: be empty itself. This condition is expressed by the <tt>Empty</tt> keyword,
1.30 cvs 3885: optionally preceded by the <tt>NOT</tt> keyword. This condition can be
3886: associated only with <a href="#sectc4232">creation rules</a>.</p>
1.18 cvs 3887: </div>
1.1 cvs 3888:
1.18 cvs 3889: <div class="subsubsection">
1.37 cvs 3890: <h4><a name="sectd42146" id="sectd42146">Conditions on counters</a></h4>
1.1 cvs 3891:
1.30 cvs 3892: <p>Presentation rules can apply when the counter's value is one, is even or
3893: odd, is equal, greater than or less than a given value or falls in a range of
1.37 cvs 3894: values. This is particularly useful for creating header and footer boxes.
1.18 cvs 3895: These conditions can be associated only with <a href="#sectc4232">creation
3896: rules</a>.</p>
1.30 cvs 3897:
3898: <p>To compare the value of a counter to a given value, a comparison is given
1.1 cvs 3899: between parentheses. The comparison is composed of the counter name followed
3900: by an equals, greater than, or less than sign and the value to which the
1.37 cvs 3901: counter will be compared. A test for whether or not a counter's value falls
3902: in a range also appears within parentheses. In this case, the counter name is
1.18 cvs 3903: followed by the <tt>IN</tt> keyword and the range definition within brackets.
3904: The <tt>Even</tt>, <tt>Odd</tt> and <tt>One</tt> are used to test a counter's
3905: value and are followed by the counter name between parentheses.</p>
1.30 cvs 3906:
3907: <p>The list of possible conditions on counters is:</p>
1.18 cvs 3908: <dl>
1.30 cvs 3909: <dt><tt>Even (Counter)</tt></dt>
3910: <dd>the box is created only if the counter has an even value.</dd>
3911: <dt><tt>Odd (Counter)</tt></dt>
3912: <dd>the box is created only if the counter has an odd value.</dd>
3913: <dt><tt>One (Counter)</tt></dt>
3914: <dd>the box is created only the counter's value is 1.</dd>
3915: <dt><tt>NOT One (Counter)</tt></dt>
3916: <dd>the box is created, unless the counter's value is 1.</dd>
3917: <dt><tt>(Counter < Value)</tt></dt>
3918: <dd>the box is created only if the counter's value is less than
3919: Value.</dd>
3920: <dt><tt>(Counter > Value)</tt></dt>
3921: <dd>the box is created only if the counter's value is greater than
3922: Value.</dd>
3923: <dt><tt>(Counter = Value)</tt></dt>
3924: <dd>the box is created only if the counter's value is equal to Value.</dd>
3925: <dt><tt>NOT (Counter = Value)</tt></dt>
3926: <dd>the is created only if the counter's value is different than
3927: Value.</dd>
3928: <dt><tt>(Counter IN [MinValue..MaxValue])</tt></dt>
3929: <dd>the box is created only if the counter's value falls in the range
3930: bounded by MinValue and MaxValue (inclusive).</dd>
3931: <dt><tt>NOT (Counter IN [MinValue..MaxValue])</tt></dt>
3932: <dd>the box is created only if the value of the counter does not fall in
3933: the range bounded by MinValue and MaxValue (inclusive).</dd>
1.18 cvs 3934: </dl>
1.30 cvs 3935:
3936: <p><strong>Note:</strong> the <tt>NOT Even</tt> and <tt>NOT Odd</tt>
3937: conditions are syntactically correct but can be expressed more simply by
3938: <tt>Odd</tt> and <tt>Even</tt>, respectively.</p>
1.18 cvs 3939: </div>
3940: </div>
1.1 cvs 3941:
1.18 cvs 3942: <div class="subsection">
1.37 cvs 3943: <h3><a name="sectc4215" id="sectc4215">A presentation rule</a></h3>
1.1 cvs 3944:
1.34 cvs 3945: <p>A presentation rule defines either a presentation property or presentation
1.37 cvs 3946: function. The properties are:</p>
1.18 cvs 3947: <ul>
1.30 cvs 3948: <li>the position of the vertical and horizontal reference axes of the
3949: box,</li>
3950: <li>the position of the box in relation to other boxes,</li>
3951: <li>the height or width of the box, with overflow exceptions,</li>
3952: <li>the margins, padding and borders of the box,</li>
3953: <li>the characteristics of the lines contained in the box: linespacing,
1.35 cvs 3954: indentation of the first line, hyphenation,</li>
1.30 cvs 3955: <li>the conditions for breaking the box across pages,</li>
3956: <li>the characteristics of the characters contained in the box: size, font,
3957: style, underlining,</li>
3958: <li>the depth of the box among overlapping boxes (often called stacking
3959: order),</li>
3960: <li>the characteristics of graphic elements contained in the box: style and
3961: thickness of lines, fill pattern for closed objects,</li>
1.37 cvs 3962: <li>the colors in text, graphics, pictures, and symbols contained in the
3963: box are displayed or printed,</li>
1.30 cvs 3964: <li>for presentation boxes only, the contents of the box.</li>
3965: </ul>
3966:
1.37 cvs 3967: <p>The <a name="presfunct" id="presfunct">presentation functions</a> are:</p>
1.30 cvs 3968: <ul>
3969: <li>the creation of a presentation box</li>
3970: <li>the line-breaking or page-breaking style,</li>
3971: <li>the copying of another box,</li>
3972: <li>the display of the box background and border,</li>
3973: <li>the display of a background picture and its aspect.</li>
3974: </ul>
3975:
1.37 cvs 3976: <p>For each box and each view, every presentation property is defined once
3977: and only once, either explicitly or by the <a href="#sectc427">default
3978: rules</a>. In contrast, presentation functions are not obligatory and can
3979: appear many times for the same element. for example an element can create
3980: many presentation boxes. Another element may not use any presentation
1.18 cvs 3981: functions.</p>
1.30 cvs 3982:
1.34 cvs 3983: <p>Each rule defining a presentation property begins with a keyword followed
1.37 cvs 3984: by a colon. The keyword indicates the property which is the subject of the
3985: rule. After the keyword and the colon, the remainder of the rule varies. All
1.18 cvs 3986: rules are terminated by a semicolon.</p>
1.34 cvs 3987: <pre> Rule = Property ';' / PresFunc ';' .
3988: Property ='VertRef' ':' PositionHoriz /
1.6 cvs 3989: 'HorizRef' ':' PositionVert /
3990: 'VertPos' ':' VPos /
3991: 'HorizPos' ':' HPos /
3992: 'Height' ':' Dimension /
3993: 'Width' ':' Dimension /
3994: 'VertOverflow' ':' Boolean /
1.1 cvs 3995: 'HorizOverflow' ':' Boolean /
1.26 cvs 3996: 'MarginTop' ':' MarginWidth /
3997: 'MarginRight' ':' MarginWidth /
3998: 'MarginBottom' ':' MarginWidth /
3999: 'MarginLeft' ':' MarginWidth /
4000: 'PaddingTop' ':' PaddingWidth /
4001: 'PaddingRight' ':' PaddingWidth /
4002: 'PaddingBottom' ':' PaddingWidth /
4003: 'PaddingLeft' ':' PaddingWidth /
4004: 'BorderTopWidth' ':' BorderWidth /
4005: 'BorderRightWidth' ':' BorderWidth /
4006: 'BorderBottomWidth' ':' BorderWidth /
4007: 'BorderLeftWidth' ':' BorderWidth /
4008: 'BorderTopColor' ':' BorderColor /
4009: 'BorderRightColor' ':' BorderColor /
4010: 'BorderBottomColor' ':' BorderColor /
4011: 'BorderLeftColor' ':' BorderColor /
4012: 'BorderTopStyle' ':' BorderStyle /
4013: 'BorderRightStyle' ':' BorderStyle /
4014: 'BorderBottomStyle' ':' BorderStyle /
4015: 'BorderLeftStyle' ':' BorderStyle .
1.6 cvs 4016: 'LineSpacing' ':' DistanceInherit /
4017: 'Indent' ':' DistanceInherit /
4018: 'Adjust' ':' AdjustInherit /
4019: 'Hyphenate' ':' BoolInherit /
4020: 'PageBreak' ':' Boolean /
4021: 'LineBreak' ':' Boolean /
4022: 'InLine' ':' Boolean /
4023: 'NoBreak1' ':' AbsDist /
4024: 'NoBreak2' ':' AbsDist /
4025: 'Gather' ':' Boolean /
4026: 'Visibility' ':' NumberInherit /
4027: 'Size' ':' SizeInherit /
4028: 'Font' ':' NameInherit /
4029: 'Style' ':' StyleInherit /
1.23 cvs 4030: 'Weight' ':' WeightInherit /
1.6 cvs 4031: 'Underline' ':' UnderLineInherit /
4032: 'Thickness' ':' ThicknessInherit /
4033: 'Depth' ':' NumberInherit /
4034: 'LineStyle' ':' LineStyleInherit /
4035: 'LineWeight' ':' DistanceInherit /
4036: 'FillPattern' ':' NameInherit /
4037: 'Background' ':' NameInherit /
1.13 cvs 4038: 'Foreground' ':' NameInherit /
1.6 cvs 4039: 'Content' ':' VarConst .
1.1 cvs 4040: PresFunc = Creation '(' BoxID ')' /
4041: 'Line' /
4042: 'NoLine' /
4043: 'Page' '(' BoxID ')' /
1.13 cvs 4044: 'Copy' '(' BoxTypeToCopy ')' /
4045: 'ShowBox' /
1.18 cvs 4046: 'BackgroundPicture' ':' FileName /
4047: 'PictureMode' ':' PictMode /</pre>
4048: </div>
4049:
4050: <div class="subsection">
1.37 cvs 4051: <h3><a name="sectc4216" id="sectc4216">Box axes</a></h3>
1.18 cvs 4052:
1.30 cvs 4053: <p>The position of the middle axes <tt>VMiddle</tt> and <tt>HMiddle</tt> in
1.1 cvs 4054: relation to their box is always calculated automatically as a function of the
1.37 cvs 4055: height and width of the box and is not specified by the presentation rules.
4056: In the presentation schema, these middle axes are used only to position their
4057: box with respect to another by specifying the distance between the middle
4058: axis and an axis or a side of another box (see the <a
4059: href="#sectc4218">relative position</a>).</p>
4060:
4061: <p>The reference axes of a box are also used to position their box in
4062: relation to another, but in contrast to the middle axes, the presentation
4063: schema must make their position explicit, either in relation to a side or the
4064: middle axis of the box itself, or in relation to an axis of an enclosed
4065: box.</p>
1.30 cvs 4066:
1.37 cvs 4067: <p>Only boxes of base elements have predefined reference axes. For character
1.1 cvs 4068: string boxes, the horizontal reference axis is the baseline of the characters
4069: (the line which passes immediately under the upper-case letters, ignoring the
4070: letter Q) and the vertical reference axis is at the left edge of the first
1.18 cvs 4071: character of the string.</p>
1.30 cvs 4072:
1.37 cvs 4073: <p>The positions of a box's reference axes are defined by the
4074: <tt>VertRef</tt> and <tt>HorizRef</tt> rules which specify the <a
4075: href="#distance">distance</a> between the reference axis and an axis or
4076: parallel side of the same box or of an enclosed box.</p>
1.18 cvs 4077: <pre> 'VertRef' ':' PositionHoriz
4078: 'HorizRef' ':' PositionVert</pre>
1.30 cvs 4079:
1.18 cvs 4080: <blockquote class="example">
1.30 cvs 4081: <p><strong>Example:</strong></p>
4082:
4083: <p>If, in the structure schema for mathematical formulas, the fraction
4084: element is defined by</p>
4085: <pre>Fraction = BEGIN
1.1 cvs 4086: Numerator = Expression;
4087: Denominator = Expression;
1.18 cvs 4088: END;</pre>
1.30 cvs 4089:
4090: <p>then the horizontal reference axis of the fraction can be positioned on
4091: top of the denominator by the rule:</p>
4092: <pre>Fraction :
1.1 cvs 4093: BEGIN
4094: HorizRef : Enclosed Denominator . Top;
4095: ...
1.18 cvs 4096: END;</pre>
1.30 cvs 4097:
4098: <p>To put the horizontal reference axis of a column at its middle:</p>
4099: <pre>Column :
1.1 cvs 4100: BEGIN
4101: HorizRef : * . HMiddle;
4102: ...
1.18 cvs 4103: END;</pre>
4104: </blockquote>
4105: </div>
1.1 cvs 4106:
1.18 cvs 4107: <div class="subsection">
1.37 cvs 4108: <h3><a name="sectc4217" id="sectc4217">Distance units</a></h3>
1.1 cvs 4109:
1.30 cvs 4110: <p>Some distances and dimensions appear in many rules of a presentation
4111: schema, especially in position rules (<tt>VertPos, HorizPos</tt>), in extent
4112: rules for boxes (<tt>Height, Width</tt>), in rules defining lines
1.37 cvs 4113: (<tt>LineSpacing, Indent</tt>), in rules controlling pagination
4114: (<tt>NoBreak1, NoBreak2</tt>) and in rules specifying the thickness of
4115: strokes (<tt>LineWeight</tt>).</p>
1.30 cvs 4116:
4117: <p>In all these rules, the distance or extent can be expressed</p>
4118: <ul>
4119: <li>either in relative units, which depend on the size of the characters in
4120: the current font: height of the element's font or height of the letter
4121: 'x',</li>
1.37 cvs 4122: <li>or in absolute units: centimeter, millimeter, inch, typographer's
4123: point, pica or pixel.</li>
1.30 cvs 4124: </ul>
4125:
1.37 cvs 4126: <p>Units can be chosen freely. Thus, it is possible to use relative units in
1.30 cvs 4127: one rule, centimeters in the next rule, and typographer's points in
4128: another.</p>
4129:
1.37 cvs 4130: <p>Absolute units are used to set rigid rules for the appearance of
4131: documents. In contrast, relative units allow changes of scale. The editor
4132: lets the value of relative units be changed dynamically. Such changes affect
4133: every box using relative units simultaneously and in the same proportion.
4134: Changing the value of the relative units affects the size of the characters
4135: and graphical elements, and the size of the boxes and the distances between
4136: them.</p>
4137:
4138: <p>A <a name="distance" id="distance">distance</a> or extent is specified by
4139: a number, which may be followed by one or more spaces and a units keyword.
4140: When there is no units keyword, the number specifies the number of relative
4141: units, where a relative unit is the height of a character in the current font
4142: (an em). When the number is followed by a units keyword, the keyword
4143: indicates the type of absolute units:</p>
1.18 cvs 4144: <ul>
1.30 cvs 4145: <li><tt>em</tt>: height of the element's font,</li>
4146: <li><tt>ex</tt>: height of the letter 'x',</li>
4147: <li><tt>cm</tt>: centimeter,</li>
4148: <li><tt>mm</tt>: millimeter,</li>
4149: <li><tt>in</tt>: inch (1 in = 2.54 cm),</li>
4150: <li><tt>pt</tt>: point (1 pt = 1/72 in),</li>
4151: <li><tt>pc</tt>: pica (1 pc = 12 pt),</li>
4152: <li><tt>px</tt>: pixel.</li>
1.18 cvs 4153: </ul>
1.30 cvs 4154:
4155: <p>Whatever the chosen unit, relative or absolute, the number is not
1.37 cvs 4156: necessarily an integer and may be expressed in fixed point notation (using
4157: the American convention of a period to express the decimal point).</p>
1.30 cvs 4158:
1.37 cvs 4159: <p>If the distance appears in a presentation rule for a numeric attribute,
4160: the number can be replaced by the name of an attribute. In this case, the
4161: value of the attribute is used. Obviously, the attribute name cannot be
4162: followed by a decimal point and a fractional part, but it can be followed a
4163: units keyword. However, the choice of units is limited to em, ex, pt and
4164: px.</p>
1.18 cvs 4165: <pre> Distance = [ Sign ] AbsDist .
1.1 cvs 4166: Sign ='+' / '-' .
4167: AbsDist = IntegerOrAttr [ '.' DecimalPart ]
4168: [ Unit ].
4169: IntegerOrAttr = IntegerPart / AttrID .
4170: IntegerPart = NUMBER .
4171: DecimalPart = NUMBER .
4172: Unit ='em' / 'ex' / 'cm' / 'mm' / 'in' / 'pt' /
1.18 cvs 4173: 'pc' / 'px' / '%' .</pre>
1.30 cvs 4174:
1.18 cvs 4175: <blockquote class="example">
1.30 cvs 4176: <p><strong>Example:</strong></p>
4177:
4178: <p>The following rules specify that a box has a height of 10.5 centimeters
4179: and a width of 5.3 ems:</p>
4180: <pre>Height : 10.5 cm;
1.18 cvs 4181: Width : 5.3;</pre>
4182: </blockquote>
4183: </div>
1.1 cvs 4184:
1.18 cvs 4185: <div class="subsection">
1.37 cvs 4186: <h3><a name="sectc4218" id="sectc4218">Relative positions</a></h3>
1.1 cvs 4187:
1.37 cvs 4188: <p>The positioning of boxes uses the eight axes and sides, the sides
4189: generally being used to define the juxtapositioning (vertical or horizontal)
4190: of boxes, the middle axes being used to define centering, and the reference
4191: axes being used for alignment.</p>
4192:
4193: <p>Two rules allow a box to be placed relative to other boxes. The
4194: <tt>VertPos</tt> rule positions the box vertically. The <tt>HorizPos</tt>
4195: rule positions the box horizontally. It is possible that a box's position
4196: could be entirely determined by other boxes positioned relative to it. In
4197: this case, the position is implicit and the word <tt>nil</tt> can be used to
4198: specify that no position rule is needed. Otherwise, an explicit rule must be
1.18 cvs 4199: given by indicating the axis or side which defines the position of the box,
4200: followed by an equals sign and the distance between between this axis or side
1.37 cvs 4201: and a parallel axis or side of another box, called the reference box. The box
1.18 cvs 4202: for which the rule is written will be positioned relative to the reference
4203: box.</p>
4204: <pre> 'VertPos' ':' VPos
1.6 cvs 4205: 'HorizPos' ':' HPos
4206: HPos = 'nil' / VertAxis '=' HorizPosition
4207: [ 'UserSpecified' ].
4208: VPos = 'nil' / HorizAxis '=' VertPosition
4209: [ 'UserSpecified' ].
1.1 cvs 4210: VertAxis = 'Left' / 'VMiddle' / 'VRef' / 'Right' .
1.18 cvs 4211: HorizAxis = 'Top' / 'HMiddle' / 'HRef' / 'Bottom' .</pre>
1.30 cvs 4212:
1.37 cvs 4213: <p>The reference box is an adjacent box: enclosing, enclosed or adjacent.
4214: When a rule is associated with a reference type attribute (and only in this
4215: case), it can be a box of the element designated by the attribute. The
4216: reference box can be either a presentation box previously defined in the
4217: <tt>BOXES</tt> section of the schema and created by a creation function, or
4218: the box associated with a structured element.</p>
4219:
4220: <p>The structural position of the reference box (relative to the box for
4221: which the rule is being written) is indicated by a keyword:
4222: <tt>Enclosing</tt>, <tt>Enclosed</tt>, or, for sibling boxes,
4223: <tt>Previous</tt> or <tt>Next</tt>. The reference attributes, or presentation
4224: boxes created by a reference attribute, the <tt>Referred</tt> keyword may be
4225: used to designate the element which the reference points to. The keyword
4226: <tt>Creator</tt> can be used in rules for presentation boxes to designate the
4227: box of the element which created the presentation box. Finally, the
4228: <tt>Root</tt> keyword can be used to designate the root of the document.</p>
1.30 cvs 4229:
4230: <p>When the keyword is ambiguous, it is followed by the name of an element
4231: type or presentation box which resolves the ambiguity (the <tt>Creator</tt>
1.37 cvs 4232: and <tt>Root</tt> keywords are never ambiguous). If this name is not given,
1.30 cvs 4233: then the first box encountered is used as the reference box. It is also
4234: possible to use just the name of an element type or presentation box without
1.37 cvs 4235: an initial keyword. In this case, a sibling having that name will be used. If
1.30 cvs 4236: the name is preceded by the keyword <tt>NOT</tt>, then the reference box will
4237: be the first box whose type is not the named one.</p>
4238:
4239: <p>In place of the box or type name, the keywords <tt>AnyElem</tt>,
1.18 cvs 4240: <tt>AnyBox</tt> and <tt>ElemWithAttr</tt> can be used, representing
1.17 cvs 4241: respectively, any structured element box, any presentation box, and the box
4242: corresponding to any structured element having a particular attribute,
4243: whatever its value; the name of this attribute must follow the keyword
1.18 cvs 4244: <tt>ElemWithAttr</tt>.</p>
1.30 cvs 4245:
4246: <p>A type name may be preceded by a star in order to resolve the ambiguity in
4247: the special case where the structure schema defines an <a
1.18 cvs 4248: href="#sectd3284">inclusion</a> without expansion (or with partial expansion)
1.37 cvs 4249: of the same type as an element of the scheme. For mark pairs (and only for <a
1.18 cvs 4250: href="#sectd3285">mark pairs</a>) the type name <em>must</em> be preceded by
4251: the <tt>First</tt> or <tt>Second</tt> keyword, which indicates which of the
1.37 cvs 4252: two marks of the pair should be used as the reference box.</p>
1.30 cvs 4253:
4254: <p>The star character ('<tt>*</tt>') used alone designates the box to which
1.37 cvs 4255: the rule applies (in this case, it is obviously useless to specify the type
4256: of the reference box).</p>
1.30 cvs 4257:
1.37 cvs 4258: <p>The keywords <tt>Enclosing</tt> and <tt>Enclosed</tt> can be used no
4259: matter what constructor defines the type to which the rule applies. When
4260: applied to the element which represents the entire document,
4261: <tt>Enclosing</tt> designates the window or page in which the document's
4262: image is displayed for the view to which the rule applies. A box or type name
4263: without a keyword is used for aggregate elements and designates another
4264: element of the same aggregate. It can also be used to designate a
4265: presentation or page layout box. The keywords <tt>Previous</tt> and
4266: <tt>Next</tt> are primarily used to denote list elements, but can also be
4267: used to denote elements of an aggregate.</p>
4268:
4269: <p>In the position rule, the structural position relative to the reference
4270: box is followed, after a period, by the name of an axis or side. The rule
4271: specifies its node's position as being some distance from this axis or side
4272: of the reference box. If this distance is zero, then the distance does not
4273: appear in the rule. Otherwise, it does appear as a positive or negative
1.30 cvs 4274: number (the sign is required for negative numbers). The sign takes into
4275: account the orientation of the coordinate axes: for top to bottom for the
1.37 cvs 4276: vertical axis and from left to right for the horizontal axis. Thus, a
1.30 cvs 4277: negative distance in a vertical position indicates that the side or axis
4278: specified in the rule is above the side or axis of the reference box.</p>
4279:
1.37 cvs 4280: <p>The distance can be followed by the <tt>UserSpecified</tt> keyword (even
4281: if the distance is nil and does not appear, the <tt>UserSpecified</tt>
4282: keyword can be used). It indicates that when the element to which the rule
4283: applies is being created, the editor will ask the user to specify the
4284: distance himself, using the mouse. In this case, the distance specified in
4285: the rule is a default distance which is suggested to the user but can be
4286: modified. The <tt>UserSpecified</tt> keyword can be used either in the
4287: vertical position rule, the horizontal position rule, or both.</p>
1.18 cvs 4288: <pre> VertPosition = Reference '.' HorizAxis [ Distance ] .
1.1 cvs 4289: HorizPosition = Reference '.' VertAxis [ Distance ] .
4290: Reference ='Enclosing' [ BoxTypeNot ] /
4291: 'Enclosed' [ BoxTypeNot ] /
4292: 'Previous' [ BoxTypeNot ] /
4293: 'Next' [ BoxTypeNot ] /
4294: 'Referred' [ BoxTypeNot ] /
4295: 'Creator' /
4296: 'Root' /
4297: '*' /
4298: BoxOrType .
4299: BoxOrType = BoxID /
4300: [ '*' ] [ FirstSec ] ElemID /
1.17 cvs 4301: 'AnyElem' / 'AnyBox' /
4302: 'ElemWithAttr' AttrID .
1.18 cvs 4303: BoxTypeNot = [ 'NOT' ] BoxOrType .</pre>
1.30 cvs 4304:
1.18 cvs 4305: <blockquote class="example">
1.30 cvs 4306: <p><strong>Example:</strong></p>
4307:
1.37 cvs 4308: <p>If a <a name="expos1" id="expos1">report</a> is defined by the following
4309: structure schema:</p>
1.30 cvs 4310: <pre>Report = BEGIN
1.6 cvs 4311: Title = Text;
4312: Summary = Text;
4313: Keywords = Text;
4314: ...
1.18 cvs 4315: END;</pre>
1.30 cvs 4316:
4317: <p>then the presentation schema could contain the rules:</p>
4318: <pre>Report : BEGIN
1.6 cvs 4319: VertPos : Top = Enclosing . Top;
4320: HorizPos : Left = Enclosing . Left;
4321: ...
1.18 cvs 4322: END;</pre>
1.30 cvs 4323:
1.37 cvs 4324: <p>These rules place the <a name="reportexample"
4325: id="reportexample">report</a> in the upper left corner of the enclosing
4326: box, which is the window in which the document is being edited.</p>
1.30 cvs 4327: <pre>Title : BEGIN
1.6 cvs 4328: VertPos : Top = Enclosing . Top + 1;
4329: HorizPos : VMiddle = Enclosing . VMiddle;
4330: ...
1.18 cvs 4331: END;</pre>
1.30 cvs 4332:
1.37 cvs 4333: <p>The top of the title is one line (a line has the height of the
4334: characters of the title) from the top of the report, which is also the top
4335: of the editing window. The title is centered horizontally in the window
4336: (see <a href="#posdim">figure</a>).</p>
1.30 cvs 4337: <pre>Summary : BEGIN
1.1 cvs 4338: VertPos : Top = Title . Bottom + 1.5;
4339: HorizPos : Left = Enclosing . Left + 2 cm;
4340: ...
1.18 cvs 4341: END;</pre>
1.30 cvs 4342:
1.37 cvs 4343: <p>The top of the summary is place a line and a half below the bottom of
4344: the title and is shifted two centimeters from the side of the window.</p>
1.18 cvs 4345: </blockquote>
1.30 cvs 4346:
1.18 cvs 4347: <blockquote class="example">
1.30 cvs 4348: <p><strong>Example:</strong></p>
4349:
1.37 cvs 4350: <p>Suppose there is a <a name="expos2" id="expos2">Design</a> logical
4351: structure which contains graphical elements:</p>
1.30 cvs 4352: <pre>Design = LIST OF (ElemGraph = GRAPHICS);</pre>
4353:
4354: <p>The following rules allow the user to freely choose the position of each
4355: element when it is created:</p>
4356: <pre>ElemGraph =
1.1 cvs 4357: BEGIN
4358: VertPos : Top = Enclosing . Top + 1 cm UserSpecified;
4359: HorizPos: Left = Enclosing . Left UserSpecified;
4360: ...
1.18 cvs 4361: END;</pre>
1.30 cvs 4362:
4363: <p>Thus, when a graphical element is created, its default placement is at
4364: the left of the window and 1 cm from the top, but the user can move it
4365: immediately, simply by moving the mouse.</p>
1.18 cvs 4366: </blockquote>
4367: </div>
1.1 cvs 4368:
1.18 cvs 4369: <div class="subsection">
1.37 cvs 4370: <h3><a name="sectc4219" id="sectc4219">Box extents</a></h3>
1.1 cvs 4371:
1.30 cvs 4372: <p>The extents (height and width) of each box are defined by the two rules
1.37 cvs 4373: <tt>Height</tt> and <tt>Width</tt>. There are three types of extents: fixed,
1.18 cvs 4374: relative, and elastic.</p>
1.1 cvs 4375:
1.18 cvs 4376: <div class="subsubsection">
1.37 cvs 4377: <h4><a name="sectd42191" id="sectd42191">Fixed extents</a></h4>
1.1 cvs 4378:
1.30 cvs 4379: <p>A fixed dimension sets the height or width of the box independently of all
1.37 cvs 4380: other boxes. It is expressed in <a href="#sectc4217">distance units</a>. The
1.18 cvs 4381: extent can be followed by the <tt>UserSpecified</tt> keyword which indicates
1.1 cvs 4382: that when the element to which the rule applies is being created, the editor
1.37 cvs 4383: will ask the user to specify the extent himself, using the mouse. In this
1.1 cvs 4384: case, the extent specified in the rule is a default extent which is suggested
1.37 cvs 4385: to the user but can be modified. The <tt>UserSpecified</tt> keyword can be
1.18 cvs 4386: used either in the <tt>Height</tt> rule, the <tt>Width</tt> rule, or both.</p>
1.30 cvs 4387:
4388: <p>A fixed extent rule can be ended by the <tt>Min</tt> keyword, which
4389: signifies that the indicated value is a minimum, and that, if the contents of
4390: the box require it, a larger extent is possible.</p>
1.18 cvs 4391: <pre> 'Height' ':' Dimension
1.1 cvs 4392: 'Width' ':' Dimension
4393: Dimension = AbsDist [ 'UserSpecified' ] [ 'Min' ] /
1.18 cvs 4394: ...</pre>
1.30 cvs 4395:
1.18 cvs 4396: <blockquote class="example">
1.30 cvs 4397: <p><strong>Example:</strong></p>
4398:
4399: <p>Continuing with the <a href="#expos2">previous example</a>, it is
4400: possible to allow the user to choose the size of each graphical element as
4401: it is created:</p>
4402: <pre>ElemGraph : BEGIN
1.6 cvs 4403: Width : 2 cm UserSpecified;
1.1 cvs 4404: Height : 1 cm UserSpecified;
4405: ...
1.18 cvs 4406: END;</pre>
1.30 cvs 4407:
4408: <p>Thus, when a graphical element is create, it is drawn by default with a
4409: width of 2 cm and a height of 1 cm, but the user is free to resize it
4410: immediately with the mouse.</p>
4411: <pre>Summary : BEGIN
1.1 cvs 4412: Height : 5 cm Min;
4413: ...
4414: END;
4415: Keywords : BEGIN
4416: VertPos : Top = Summary . Bottom;
4417: ...
1.18 cvs 4418: END;</pre>
4419: </blockquote>
4420: </div>
1.1 cvs 4421:
1.18 cvs 4422: <div class="subsubsection">
1.37 cvs 4423: <h4><a name="sectd42192" id="sectd42192">Relative extents</a></h4>
1.30 cvs 4424:
4425: <p>A relative extent determines the extent as a function of the extent of
4426: another box, just as a relative position places a box in relation to another.
4427: The reference box in an extent rule is designated using the same syntax as is
1.37 cvs 4428: used in a relative position rule. It is followed by a period and a
1.30 cvs 4429: <tt>Height</tt> or <tt>Width</tt> keyword, depending on the extent being
1.37 cvs 4430: referred to. Next comes the relation between the extent being defined and the
4431: extent of the reference box. This relation can be either a percentage or a
1.30 cvs 4432: difference.</p>
1.1 cvs 4433:
1.37 cvs 4434: <p>A percentage is indicated by a star (the multiplication symbol) followed
4435: by the numeric percentage value (which may be greater than or less than 100)
4436: and the percent (`%') character. A difference is simply indicated by a signed
1.18 cvs 4437: difference.</p>
1.30 cvs 4438:
4439: <p>If the rule appears in the presentation rules of a numeric attribute, the
1.1 cvs 4440: percentage value can be replaced by the name of the attribute. This attribute
1.37 cvs 4441: is then used as a percentage. The attribute can also be used as part of a <a
1.18 cvs 4442: href="#distance">difference</a>.</p>
1.30 cvs 4443:
4444: <p>Just as with a fixed extent, a relative extent rule can end with the
1.18 cvs 4445: <tt>Min</tt> keyword, which signifies that the extent is a minimum and that,
4446: if the contents of the box require it, a larger extent is possible.</p>
1.30 cvs 4447:
4448: <p>A special case of relative extent rules is:</p>
1.18 cvs 4449: <pre>Height : Enclosed . Height;</pre>
1.30 cvs 4450:
4451: <p>or</p>
1.18 cvs 4452: <pre>Width : Enclosed . Width;</pre>
1.30 cvs 4453:
4454: <p>which specifies that the box has a height (or width) such that it encloses
4455: all the boxes which it contains, excluding boxes having a rule
4456: <tt>VertOverflow: Yes;</tt> or <tt>HorizOverflow: Yes;</tt>.</p>
4457:
4458: <p><strong>Note:</strong> character strings (type <tt>TEXT_UNIT</tt>)
4459: generally must use the sum of the widths of the characters which compose them
4460: as their width, which is expressed by the rule:</p>
1.18 cvs 4461: <pre>TEXT_UNIT :
4462: Width : Enclosed . Width;</pre>
1.30 cvs 4463:
4464: <p>If this rule is not the default <tt>Width</tt> rule, it must be given
1.18 cvs 4465: explicitly in the <tt>RULES</tt> section which defines the presentation rules
4466: of the logical elements.</p>
4467: <pre> 'Height' ':' Extent
1.1 cvs 4468: 'Width' ':' Extent
4469: Extent = Reference '.' HeightWidth [ Relation ]
4470: [ 'Min' ] / ...
4471: HeightWidth ='Height' / 'Width' .
4472: Relation ='*' ExtentAttr '%' / Distance .
4473: ExtentAttr = ExtentVal / AttrID .
1.18 cvs 4474: ExtentVal = NUMBER .</pre>
1.30 cvs 4475:
1.18 cvs 4476: <blockquote class="example">
1.30 cvs 4477: <p><strong>Example:</strong></p>
4478:
4479: <p>Completing the <a href="#expos1">above example</a>, it is possible to
4480: specify that the report takes its width from the editing window and its
4481: height from the size of its contents (this can obviously be greater than
4482: that of the window):</p>
4483: <pre>Report : BEGIN
1.1 cvs 4484: Width : Enclosing . Width;
4485: Height : Enclosed . Height;
4486: ...
1.18 cvs 4487: END;</pre>
1.30 cvs 4488:
4489: <p>Then, the following rules make the title occupy 60% of the width of the
4490: report (which is that of the window) and is broken into centered lines of
4491: this width (see the <a href="#sectc4222"><tt>Line</tt> rule</a>).</p>
4492: <pre>Title : BEGIN
1.1 cvs 4493: Width : Enclosing . Width * 60%;
4494: Height : Enclosed . Height;
4495: Line;
4496: Adjust : VMiddle;
4497: ...
1.18 cvs 4498: END;</pre>
1.30 cvs 4499:
4500: <p>The summary occupy the entire width of the window, with the exception of
4501: a 2 cm margin reserved by the horizontal position rule:</p>
4502: <pre>Summary : BEGIN
1.1 cvs 4503: Width : Enclosing . Width - 2 cm;
4504: Height : Enclosed . Height;
4505: ...
1.18 cvs 4506: END;</pre>
4507:
1.37 cvs 4508: <p>This set of rules, plus the <a href="#reportexample">position rules
4509: given above</a>, produce the layout of boxes shown in the following<a
1.30 cvs 4510: href="#posdim">figure</a>.</p>
4511:
4512: <div class="figure">
1.37 cvs 4513: <hr />
1.30 cvs 4514: <pre>-------------------------------------------------------------
1.1 cvs 4515: | Window and Report ^ |
4516: | | 1 line |
4517: | v |
4518: | ------------------------------------- |
4519: | | | |
4520: : 20% : Title : 20% :
1.30 cvs 4521: :<--------->: :<--------->:
1.1 cvs 4522: : : 60% : :
1.30 cvs 4523: : :<--------------------------------->: :
1.1 cvs 4524: | | | |
4525: | ------------------------------------- |
4526: | ^ |
4527: | | 1.5 line |
4528: | | |
4529: | v |
4530: | ---------------------------------------------------|
4531: | 2 cm | |
1.30 cvs 4532: |<------>| Summary |
1.18 cvs 4533: : : :</pre>
1.19 cvs 4534:
1.37 cvs 4535: <p align="center"><em><a name="posdim" id="posdim">Box position and
1.30 cvs 4536: extent</a><em></em></em></p>
1.37 cvs 4537: <hr />
1.30 cvs 4538: </div>
1.18 cvs 4539: </blockquote>
4540: </div>
1.1 cvs 4541:
1.18 cvs 4542: <div class="subsubsection">
1.37 cvs 4543: <h4><a name="sectd42193" id="sectd42193">Elastic extents</a></h4>
1.1 cvs 4544:
1.37 cvs 4545: <p>The last type of extent is the elastic extent. Either one or both extents
4546: can be elastic. A box has an elastic extent when two opposite sides are
1.30 cvs 4547: linked by distance constraints to two sides or axes of other boxes.</p>
4548:
4549: <p>One of the sides of the elastic box is linked by a position rule
1.37 cvs 4550: (<tt>VertPos</tt> or <tt>HorizPos</tt>) to a neighboring box. The other side
1.18 cvs 4551: is link to another box by a <tt>Height</tt> or <tt>Width</tt> rule, which
1.37 cvs 4552: takes the same form as the position rule. For the elastic box itself, the
1.1 cvs 4553: notions of sides (left or right, top or bottom) are fuzzy, since the movement
4554: of either one of the two reference boxes can, for example, make the left side
1.37 cvs 4555: of the elastic box move to the right of its right side. This is not
4556: important. The only requirement is that the two sides of the elastic box used
1.18 cvs 4557: in the position and extent rule are opposite sides of the box.</p>
4558: <pre> 'Height' ':' Extent
1.6 cvs 4559: 'Width' ':' Extent
1.18 cvs 4560: Extent = HPos / VPos / ...</pre>
1.30 cvs 4561:
1.18 cvs 4562: <blockquote class="example">
1.30 cvs 4563: <p><strong>Example:</strong></p>
4564:
4565: <p>Suppose we want to draw an elastic arrow or line between the middle of
1.37 cvs 4566: the bottom side of box A and the upper left corner of box B. To do this, we
1.30 cvs 4567: would define a graphics box whose upper left corner coincides with the
4568: middle of the bottom side of A (a position rule) and whose lower right
4569: corner coincides with with the upper left corner of B (dimension rules):</p>
4570: <pre>LinkedBox :
1.1 cvs 4571: BEGIN
1.6 cvs 4572: VertPos : Top = A .Bottom;
1.1 cvs 4573: HorizPos : Left = A . VMiddle;
1.6 cvs 4574: Height : Bottom = B . Top;
4575: Width : Right = B . Left;
1.18 cvs 4576: END;</pre>
4577: </blockquote>
1.30 cvs 4578:
1.18 cvs 4579: <blockquote class="example">
1.30 cvs 4580: <p><strong>Example:</strong></p>
4581:
4582: <p>The element SectionTitle creates a presentation box called SectionNum
1.37 cvs 4583: which contains the number of the section. Suppose we want to align the
4584: SectionNum and SectionTitle horizontally, have the SectionNum take its
4585: width from its contents (the section number), have the SectionTitle box
4586: begin 0.5 cm to the right of the SectionNum box and end at the right edge
4587: of its enclosing box. This would make the SectionTitle box elastic, since
4588: its width is defined by the position of its left and right sides. The
4589: following rules produce this effect:</p>
1.30 cvs 4590: <pre>SectionNum :
1.1 cvs 4591: BEGIN
4592: HorizPos : Left = Enclosing . Left;
4593: Width : Enclosed . Width;
4594: ...
4595: END;
4596:
4597: SectionTitle :
4598: BEGIN
4599: HorizPos : Left = SectionNum . Right + 0.5 cm;
4600: Width : Right = Enclosing . Right;
4601: ...
1.18 cvs 4602: END;</pre>
4603: </blockquote>
4604: </div>
4605: </div>
1.1 cvs 4606:
1.18 cvs 4607: <div class="subsection">
1.37 cvs 4608: <h3><a name="sectc4220" id="sectc4220">Overflow</a></h3>
1.1 cvs 4609:
1.30 cvs 4610: <p>A boxes corresponding to a structural element normally contain all boxes
1.37 cvs 4611: corresponding to the elements of its subtree. However, in some cases, it
1.1 cvs 4612: could be necessary to allow a box to jut out from its parent box. Two
4613: presentation rules indicate that such an overflow is allowed, one for
1.18 cvs 4614: horizontal overflow, one for vertical overflow.</p>
1.30 cvs 4615:
4616: <p>Each of these rules is expressed by a keyword followed by a colon and the
1.18 cvs 4617: keyword <tt>Yes</tt> or <tt>No</tt>.</p>
4618: <pre> 'VertOverflow' ':' Boolean /
1.1 cvs 4619: 'HorizOverflow' ':' Boolean .
1.18 cvs 4620: Boolean = 'Yes' / 'No' .</pre>
4621: </div>
1.1 cvs 4622:
1.30 cvs 4623: <p>@@@@@ ******</p>
4624:
1.26 cvs 4625: <p>Explain Margin, Padding and Border. Refer to CSS2.</p>
4626: <pre> 'MarginTop' ':' MarginWidth /
4627: 'MarginRight' ':' MarginWidth /
4628: 'MarginBottom' ':' MarginWidth /
4629: 'MarginLeft' ':' MarginWidth /
4630: 'PaddingTop' ':' PaddingWidth /
4631: 'PaddingRight' ':' PaddingWidth /
4632: 'PaddingBottom' ':' PaddingWidth /
4633: 'PaddingLeft' ':' PaddingWidth /
4634: 'BorderTopWidth' ':' BorderWidth /
4635: 'BorderRightWidth' ':' BorderWidth /
4636: 'BorderBottomWidth' ':' BorderWidth /
4637: 'BorderLeftWidth' ':' BorderWidth /
4638: 'BorderTopColor' ':' BorderColor /
4639: 'BorderRightColor' ':' BorderColor /
4640: 'BorderBottomColor' ':' BorderColor /
4641: 'BorderLeftColor' ':' BorderColor /
4642: 'BorderTopStyle' ':' BorderStyle /
4643: 'BorderRightStyle' ':' BorderStyle /
4644: 'BorderBottomStyle' ':' BorderStyle /
4645: 'BorderLeftStyle' ':' BorderStyle .
4646:
4647: MarginWidth = InheritParent / 'Auto' / Distance .
4648: PaddingWidth = InheritParent / Distance .
4649: BorderWidth = InheritParent / 'Thin' / 'Medium' / 'Thick' / Distance .
4650: BorderColor = InheritParent / 'Transparent' / 'Foreground' /
4651: ColorName .
4652: BorderStyle = InheritParent /
4653: 'None' / 'Hidden' / 'Dotted' / 'Dashed' / 'Solid' /
4654: 'Double' / 'Groove' / 'Ridge' / 'Inset' / 'Outset' .
1.27 cvs 4655: InheritParent = 'Enclosing' '=' / 'Creator' '=' .
1.26 cvs 4656: ColorName = NAME .</pre>
1.30 cvs 4657:
4658: <p>@@@@@ ******</p>
1.26 cvs 4659:
1.18 cvs 4660: <div class="subsection">
1.37 cvs 4661: <h3><a name="sectc4221" id="sectc4221">Inheritance</a></h3>
1.1 cvs 4662:
1.37 cvs 4663: <p>A presentation property can be defined by reference to the same property
4664: of another box in the tree of boxes. These structural links are expressed by
4665: kinship. The reference box can be that of the element immediately above in
1.18 cvs 4666: the structure (<tt>Enclosing</tt>), two levels above (<tt>GrandFather</tt>),
4667: immediately below (<tt>Enclosed</tt>) or immediately before
1.37 cvs 4668: (<tt>Previous</tt>). In the case of a presentation box, and only in that
1.1 cvs 4669: case, the reference box may be the element which created the presentation box
1.18 cvs 4670: (<tt>Creator</tt>).</p>
1.30 cvs 4671:
4672: <p>Kinship is expressed in terms of the logical structure of the document and
1.37 cvs 4673: not in terms of the tree of boxes. The presentation box cannot transmit any
1.34 cvs 4674: of their properties by inheritance; only structured element boxes can do so.
1.37 cvs 4675: As an example, consider an element B which follows an element A in the
4676: logical structure. The element B creates a presentation box P in front of
4677: itself, using the <tt>CreateBefore</tt> rule (see the <a
4678: href="#sectc4232">creation rules</a>). If element B's box inherits its
4679: character style using the <tt>Previous</tt> kinship operation, it gets its
4680: character style from A's box, not from P's box. Inheritance works differently
4681: for positions and extents, which can refer to presentation boxes.</p>
1.30 cvs 4682:
1.34 cvs 4683: <p>The inherited property value can be the same as that of the reference box.
1.37 cvs 4684: This is indicated by an equals sign. However, for numeric properties, a
1.1 cvs 4685: different value can be obtained by adding or subtracting a number from the
1.37 cvs 4686: reference box's property value. Addition is indicated by a plus sign before
4687: the number, while subtraction is specified with a minus sign. The value of a
1.34 cvs 4688: property can also be given a maximum (if the sign is a plus) or minimum (if
1.18 cvs 4689: the sign is a minus).</p>
1.30 cvs 4690:
4691: <p>If the rule is being applied to a numeric attribute, the number to add or
1.37 cvs 4692: subtract can be replaced by the attribute name. The value of a maximum or
4693: minimum may also be replaced by an attribute name. In these cases, the value
1.18 cvs 4694: of the attribute is used.</p>
4695: <pre> Inheritance = Kinship InheritedValue .
1.6 cvs 4696: Kinship ='Enclosing' / 'GrandFather' / 'Enclosed' /
4697: 'Previous' / 'Creator' .
1.1 cvs 4698: InheritedValue ='+' PosIntAttr [ 'Max' maximumA ] /
1.6 cvs 4699: '-' NegIntAttr [ 'Min' minimumA ] /
4700: '=' .
4701: PosIntAttr = PosInt / AttrID .
4702: PosInt = NUMBER .
4703: NegIntAttr = NegInt / AttrID .
4704: NegInt = NUMBER .
4705: maximumA = maximum / AttrID .
4706: maximum = NUMBER .
4707: minimumA = minimum / AttrID .
1.18 cvs 4708: minimum = NUMBER .</pre>
1.30 cvs 4709:
1.36 cvs 4710: <p>The properties which can be obtained by inheritance are hyphenation,
4711: interline spacing, character font (font family), font style, font size,
4712: visibility, indentation, underlining, alignment of text, stacking order of
4713: objects, the style and thickness of lines, fill pattern and the colors of
1.18 cvs 4714: lines and characters.</p>
4715: </div>
1.1 cvs 4716:
1.18 cvs 4717: <div class="subsection">
1.37 cvs 4718: <h3><a name="sectc4222" id="sectc4222">Line breaking</a></h3>
1.1 cvs 4719:
1.30 cvs 4720: <p>The <tt>Line</tt> rule specifies that the contents of the box should be
4721: broken into lines: the boxes included in the box to which this rule is
4722: attached are displayed one after the other, from left to right, with their
1.37 cvs 4723: horizontal reference axes aligned so that they form a series of lines. The
1.30 cvs 4724: length of these lines is equal to the width of the box to which the
4725: <tt>Line</tt> rule is attached.</p>
4726:
4727: <p>When an included box overflows the current line, it is either carried
1.37 cvs 4728: forward to the next line, cur, or left the way it is. The <a
1.18 cvs 4729: href="#sectc4223"><tt>LineBreak</tt> rule</a> is used to allow or prevent the
1.37 cvs 4730: breaking of included boxes. If the included box is not breakable but is
4731: longer than the space remaining on the line, it is left as is. When a
1.1 cvs 4732: character string box is breakable, the line is broken between words or, if
1.37 cvs 4733: necessary, by <a href="#sectd42225">hyphenating a word</a>. When a compound
4734: box is breakable, the box is transparent in regard to line breaking. The
4735: boxes included in the compound box are treated just like included boxes which
4736: have the <tt>LineBreak</tt> rule. Thus, it is possible to traverse a complete
1.18 cvs 4737: subtree of boxes to line break the text leaves of a complex structure.</p>
1.30 cvs 4738:
4739: <p>The relative position rules of the included boxes are ignored, since the
4740: boxes will be placed according to the line breaking rules.</p>
4741:
1.37 cvs 4742: <p>The <tt>Line</tt> rule does not have a parameter. The characteristics of
4743: the lines that will be constructed are determined by the
4744: <tt>LineSpacing</tt>, <tt>Indent</tt>, <tt>Adjust</tt>, and
4745: <tt>Hyphenate</tt> rules. Moreover, the <a
4746: href="#insectd42226"><tt>Inline</tt> rule</a> permits the exclusion of
1.36 cvs 4747: certain elements from the line breaking process.</p>
1.30 cvs 4748:
4749: <p>When the <tt>Line</tt> rule appears in the rules sequence of a non-primary
1.37 cvs 4750: view, it applies only to that view, but when the <tt>Line</tt> rule appears
4751: in the rules sequence of the primary view, it also applies to the other views
4752: by default, except for those views which explicitly invoke the
4753: <tt>NoLine</tt> rule. Thus, the <tt>NoLine</tt> rule can be used in a
4754: non-primary view to override the primary view's <tt>Line</tt> rule. The
4755: <tt>NoLine</tt> rule must not be used with the primary view because the
4756: absence of the <tt>Line</tt> rule has the same effect. Like the <tt>Line</tt>
4757: rule, the <tt>NoLine</tt> rule does not take any parameters.</p>
1.18 cvs 4758: <pre> 'Line'
4759: 'NoLine'</pre>
4760:
4761: <div class="subsubsection">
1.37 cvs 4762: <h4><a name="sectd42221" id="sectd42221">Line spacing</a></h4>
1.18 cvs 4763:
1.30 cvs 4764: <p>The <tt>LineSpacing</tt> rule defines the line spacing to be used in the
1.37 cvs 4765: line breaking process. The line spacing is the distance between the baselines
1.1 cvs 4766: (horizontal reference axis) of the successive lines produced by the
1.37 cvs 4767: <tt>Line</tt> rule. The value of the line spacing can be specified as a
4768: constant or by inheritance. It is expressed in any of the available <a
1.18 cvs 4769: href="#sectc4217">distance units</a>.</p>
1.30 cvs 4770:
4771: <p>Inheritance allows the value to be obtained from a relative in the
4772: structure tree, either without change (an equals sign appears after the
4773: inheritance keyword), with a positive difference (a plus sign), or a negative
1.37 cvs 4774: difference (a minus sign). When the rule uses a difference, the value of the
1.30 cvs 4775: difference follows the sign and is expressed as a <a
4776: href="#sectc4217">distance</a>.</p>
1.18 cvs 4777: <pre> 'LineSpacing' ':' DistOrInherit
1.6 cvs 4778: DistOrInherit = Kinship InheritedDist / Distance .
1.18 cvs 4779: InheritedDist = '=' / '+' AbsDist / '-' AbsDist .</pre>
1.30 cvs 4780:
4781: <p>When the line spacing value (or its difference from another element) is
1.37 cvs 4782: expressed in relative units, it changes with the size of the characters.
4783: Thus, when a larger font is chosen for a part of the document, the line
4784: spacing of that part expands proportionally. In contrast, when the line
4785: spacing value is expressed in absolute units (centimeters, inches,
4786: typographer's points), it is independent of the characters, which permits the
4787: maintenance of a consistent line spacing, whatever the character font. Either
4788: approach can be taken, depending on the desired effect.</p>
1.18 cvs 4789: </div>
1.1 cvs 4790:
1.18 cvs 4791: <div class="subsubsection">
1.37 cvs 4792: <h4><a name="sectd42222" id="sectd42222">First line indentation</a></h4>
1.1 cvs 4793:
1.30 cvs 4794: <p>The <tt>Indent</tt> rule is used to specify the indentation of the first
4795: line of the elements broken into lines by the <tt>Line</tt> function. The
1.1 cvs 4796: indentation determines how far the first line of the element is shifted with
1.37 cvs 4797: respect to the other lines of the same element. It can be specified as a
4798: constant or by inheritance. The constant value is a positive integer (shifted
1.1 cvs 4799: to the right; the sign is optional), a negative integer (shifted to the left)
1.37 cvs 4800: or zero (no shift). All available <a href="#sectc4217">units</a> can be
1.18 cvs 4801: used.</p>
1.30 cvs 4802:
4803: <p>Indentation can be defined for any box, regardless of whether the box is
4804: line broken, and transmitted by inheritance to elements that are line broken.
4805: The size of the indentation is specified in the same manner as the <a
1.18 cvs 4806: href="#sectd42221">line spacing</a>.</p>
4807: <pre> 'Indent' ':' DistOrInherit</pre>
4808: </div>
1.1 cvs 4809:
1.18 cvs 4810: <div class="subsubsection">
1.37 cvs 4811: <h4><a name="sectd42223" id="sectd42223">Alignment</a></h4>
1.1 cvs 4812:
1.30 cvs 4813: <p>The alignment style of the lines constructed during line breaking is
1.37 cvs 4814: defined by the <tt>Adjust</tt> rule. The alignment value can be a constant or
4815: inherited. A constant value is specified by a keyword:</p>
1.18 cvs 4816: <ul>
1.30 cvs 4817: <li><tt>Left</tt>: at the left edge,</li>
4818: <li><tt>Right</tt>: at the right edge,</li>
4819: <li><tt>VMiddle</tt>: centered</li>
1.35 cvs 4820: <li><tt>Justify</tt>: justified</li>
1.30 cvs 4821: <li><tt>LeftWithDots</tt>: at the left edge with a dotted line filling out
4822: the last line up to the right edge of the line breaking box.</li>
1.18 cvs 4823: </ul>
1.30 cvs 4824:
1.37 cvs 4825: <p>An inherited value can only be the same as that of the reference box and
4826: is specified by a kinship keyword followed by an equals sign.</p>
1.18 cvs 4827: <pre> 'Adjust' ':' AlignOrInherit
1.1 cvs 4828: AlignOrInherit = Kinship '=' / Alignment .
1.35 cvs 4829: Alignment = 'Left' / 'Right' / 'VMiddle' / 'Justify' /
1.18 cvs 4830: 'LeftWithDots' .</pre>
4831: </div>
1.1 cvs 4832:
1.18 cvs 4833: <div class="subsubsection">
1.37 cvs 4834: <h4><a name="sectd42225" id="sectd42225">Hyphenation</a></h4>
1.18 cvs 4835:
1.37 cvs 4836: <p>The <tt>Hyphenate</tt> rule indicates whether or not words should be
4837: broken by hyphenation at the end of lines. It affects the lines produced by
4838: the <tt>Line</tt> rule and contained in the box carrying the
4839: <tt>Hyphenate</tt> rule.</p>
1.30 cvs 4840:
1.34 cvs 4841: <p>The hyphenation property takes a boolean value, which can be either
1.37 cvs 4842: constant or inherited. A constant boolean value is expressed by either the
4843: <tt>Yes</tt> or the <tt>No</tt> keyword. An inherited value can only be the
1.1 cvs 4844: same as that of the reference box and is specified by a kinship keyword
1.18 cvs 4845: followed by an equals sign.</p>
4846: <pre> 'Hyphenate' ':' BoolInherit
1.1 cvs 4847: BoolInherit = Boolean / Kinship '=' .
1.18 cvs 4848: Boolean = 'Yes' / 'No' .</pre>
4849: </div>
4850:
4851: <div class="subsubsection">
1.37 cvs 4852: <h4><a name="sectd42226" id="sectd42226">Avoiding line breaking</a></h4>
1.18 cvs 4853:
1.37 cvs 4854: <p>The <tt>InLine</tt> rule is used to specify that a box that would
4855: otherwise participate in line breaking asked for by the <tt>Line</tt> rule of
4856: an enclosing box, instead avoids the line breaking process and positions
4857: itself according to the <tt>HorizPos</tt> and <tt>VertPos</tt> rules that
4858: apply to it. When the <tt>InLine</tt> rule applies to a box which would not
4859: be line broken, it has no effect.</p>
1.30 cvs 4860:
4861: <p>The rule is expressed by the <tt>InLine</tt> keyword followed by a colon
4862: and the keyword <tt>Yes</tt>, if the box should participate in line breaking,
1.37 cvs 4863: or the keyword <tt>No</tt>, if it should not. This is the only form possible:
4864: this rule cannot be inherited. Moreover, it can only appear in the rules of
1.1 cvs 4865: the primary view and applies to all views defined in the presentation
1.18 cvs 4866: schema.</p>
4867: <pre> 'InLine' ':' Boolean .
4868: Boolean = 'Yes' / 'No' .</pre>
1.30 cvs 4869:
1.18 cvs 4870: <blockquote class="example">
1.30 cvs 4871: <p><strong>Example:</strong></p>
4872:
4873: <p>Suppose the structure schema defines a logical attribute called
1.37 cvs 4874: <tt>New</tt> which is used to identify the passages in a document which
4875: were recently modified. It would be nice to have the presentation schema
4876: make a bar appear in the left margin next to each passage having the
4877: <tt>New</tt> attribute. A new passage can be an entire element, such as a
4878: paragraph or section, or it can be some words in the middle of a paragraph.
4879: To produce the desired effect, the <tt>New</tt> attribute is given a
4880: creation rule which generates a <tt>VerticalBar</tt> presentation box.</p>
1.30 cvs 4881:
4882: <p>When the <tt>New</tt> attribute is attached to a character string which
4883: is inside a line broken element (inside a paragraph, for example), the bar
4884: is one of the elements which participates in line breaking and it is placed
4885: normally in the current line, at the end of the character string which has
1.37 cvs 4886: the attribute. To avoid this, the <tt>InLine</tt> rule is used in the
1.30 cvs 4887: following way:</p>
4888: <pre>BOXES
1.1 cvs 4889: VerticalBar:
4890: BEGIN
4891: Content: Graphics 'l';
4892: HorizPos: Left = Root . Left;
4893: VertPos: Top = Creator . Top;
4894: Height: Bottom = Creator . Bottom;
4895: Width: 1 pt;
4896: InLine: No;
4897: ...
4898: END;
4899: ...
4900: ATTRIBUTES
4901: Nouveau:
4902: BEGIN
4903: CreateAfter(VerticalBar);
1.18 cvs 4904: END;</pre>
4905: </blockquote>
4906: </div>
4907: </div>
1.1 cvs 4908:
1.18 cvs 4909: <div class="subsection">
1.37 cvs 4910: <h3><a name="sectc4223" id="sectc4223">Page breaking and line breaking
4911: conditions</a></h3>
1.1 cvs 4912:
1.30 cvs 4913: <p>Pages are constructed by the editor in accordance with the model specified
1.37 cvs 4914: by a <a href="#sectc4233"><tt>Page</tt> rule</a>. The page model describes
1.30 cvs 4915: only the composition of the pages but does not give any rules for breaking
1.37 cvs 4916: different element types across pages. Now, it is possible that certain
4917: elements must not be cut by page breaks, while others can be cut anywhere.
4918: The <tt>PageBreak</tt>, <tt>NoBreak1</tt>, and <tt>NoBreak2</tt> rules are
4919: used to specify the conditions under which each element type can be cut.</p>
1.30 cvs 4920:
4921: <p>The <tt>PageBreak</tt> rule is used to indicate whether or not the box can
1.37 cvs 4922: be cut during the construction of pages. If cutting is authorized, the box
4923: can be cut, with one part appearing at the bottom of a page and the other
4924: part appearing at the top of the next page. The rule is formed by the
1.18 cvs 4925: <tt>PageBreak</tt> keyword followed by a colon and a constant boolean value
1.37 cvs 4926: (<tt>Yes</tt> or <tt>No</tt>). This is the only form possible: this rule
4927: cannot be inherited. Moreover, it can only appear in the rules of the primary
1.18 cvs 4928: view and applies to all views defined in the presentation schema.</p>
1.30 cvs 4929:
4930: <p>Whether objects can be cut by line breaks can be controlled in a similar
1.37 cvs 4931: way using the <tt>LineBreak</tt> rule. This rule allows the specification of
4932: whether or not the box can be cut during the construction of lines. If
1.1 cvs 4933: cutting is authorized, the box can be cut, with one part appearing at the end
1.37 cvs 4934: of a line and the other part appearing at the beginning of the next line. The
1.18 cvs 4935: rule is formed by the <tt>LineBreak</tt> keyword followed by a colon and a
1.37 cvs 4936: constant boolean value (<tt>Yes</tt> or <tt>No</tt>). This is the only form
4937: possible: this rule cannot be inherited. Moreover, it can only appear in the
4938: rules of the primary view and applies to all views defined in the
4939: presentation schema.</p>
1.18 cvs 4940: <pre> 'PageBreak' ':' Boolean .
1.1 cvs 4941: 'LineBreak' ':' Boolean .
1.18 cvs 4942: Boolean = 'Yes' / 'No' .</pre>
1.30 cvs 4943:
4944: <p>When a box can be cut by a page break, it is possible that a page break
4945: will fall an inappropriate spot, creating, for example, a widow or orphan, or
1.37 cvs 4946: separating the title of a section from the first paragraph of the section.
4947: The <tt>NoBreak1</tt> and <tt>NoBreak2</tt> rules are used to avoid this.
4948: They specify that the box of the element to which they apply cannot be cut
4949: within a certain zone at the top (<tt>NoBreak1</tt> rule) or at the bottom
4950: (<tt>NoBreak2</tt> rule). These two rules specify the height of the zones in
1.18 cvs 4951: which page breaks are prohibited.</p>
1.30 cvs 4952:
4953: <p>The <tt>NoBreak1</tt> and <tt>NoBreak2</tt> rules give the height of the
1.37 cvs 4954: zone in which page breaking is prohibited. The height is given as a constant
1.30 cvs 4955: value using any of the <a href="#sectc4217">available units</a>, absolute or
1.37 cvs 4956: relative. The value may not be inherited.</p>
1.18 cvs 4957: <pre> 'NoBreak1' ':' AbsDist .
4958: 'NoBreak2' ':' AbsDist .</pre>
1.30 cvs 4959:
1.18 cvs 4960: <blockquote class="example">
1.30 cvs 4961: <p><strong>Example:</strong></p>
4962:
4963: <p>The following rules prevent widows and orphans in a paragraph:</p>
4964: <pre>Paragraph :
1.1 cvs 4965: BEGIN
4966: NoBreak1 : 2;
4967: NoBreak2 : 2;
1.18 cvs 4968: END;</pre>
1.30 cvs 4969:
1.37 cvs 4970: <p>This rule prevents a section title from becoming separated from the
4971: first paragraph of the section by prohibiting page breaks at the beginning
4972: of the section rule:</p>
1.30 cvs 4973: <pre>Section :
1.18 cvs 4974: NoBreak1 : 1.5 cm;</pre>
1.30 cvs 4975:
4976: <p>Finally, this rule prevents a figure from being page broken in any
4977: way:</p>
4978: <pre>Figure :
1.18 cvs 4979: PageBreak : No;</pre>
4980: </blockquote>
1.30 cvs 4981:
4982: <p>The Thot editor constructs the document images displayed on the screen
1.37 cvs 4983: dynamically. As the user moves in the document or makes the document scroll
1.1 cvs 4984: in a window, the editor constructs the image to be displayed in little bits,
1.37 cvs 4985: filling the gaps which are produced in the course of these operations. It
1.1 cvs 4986: stops filling in the image when an element reaches the edge of the window in
1.37 cvs 4987: which the gap appears. If the appearance of the document is complex, it is
1.1 cvs 4988: possible that the image in incomplete, even though the edge of the window was
1.37 cvs 4989: reached. For example, an element might need to be presented to the side of
4990: the last element displayed, but its image was not constructed. The user will
1.1 cvs 4991: not know whether the element is really absent or if its image has simply not
1.18 cvs 4992: been constructed.</p>
1.30 cvs 4993:
1.37 cvs 4994: <p>The <tt>Gather</tt> rule is used to remedy this problem. When the rule
1.18 cvs 4995: <tt>Gather : Yes;</tt> is associated with an element type, the image of such
4996: elements is constructed as a block by the editor: it is never split up.</p>
1.30 cvs 4997:
4998: <p>The <tt>Gather</tt> rule may not appear in the <a href="#sectc427">default
1.37 cvs 4999: rules</a>. Elements which do not have the <tt>Gather</tt> rule are considered
5000: susceptible to being split up during display. Thus, it is not necessary to
1.18 cvs 5001: use the <tt>Gather : No;</tt> form. This rule must be used prudently and only
1.37 cvs 5002: for those elements which truly need it. If used incorrectly, it can
1.18 cvs 5003: pointlessly increase the size of the image constructed by the editor and lead
5004: to excessive memory consumption by the editor.</p>
1.30 cvs 5005:
5006: <p>Like the <tt>PageBreak</tt> and <tt>LineBreak</tt> rules, the
5007: <tt>Gather</tt> rule can only appear in rules of the primary view and applies
5008: to all views defined in the presentation schema.</p>
1.18 cvs 5009: <pre> 'Gather' ':' Boolean .</pre>
5010: </div>
1.1 cvs 5011:
1.18 cvs 5012: <div class="subsection">
1.37 cvs 5013: <h3><a name="sectc4224" id="sectc4224">Visibility</a></h3>
1.1 cvs 5014:
1.34 cvs 5015: <p>The visibility property is used to control which elements should or should
1.37 cvs 5016: not be displayed, based on context. An element can have different
5017: visibilities in different views. If an element's visibility is zero for a
5018: view, that element is not displayed in that view and does not occupy any
5019: space (its extents are zero).</p>
1.30 cvs 5020:
1.37 cvs 5021: <p>Visibility takes non-negative integer values (positive or zero). If values
1.1 cvs 5022: greater than 1 are used, they allow the user to choose a degree of visibility
1.37 cvs 5023: and, thus, to see only those boxes whose visibility property exceeds a
5024: certain threshold. This gives the user control over the granularity of the
5025: displayed pictures.</p>
1.30 cvs 5026:
1.34 cvs 5027: <p>The visibility property can be defined as a constant or by inheritance. If
1.1 cvs 5028: defined by inheritance, it cannot be based on the value of the next or
1.37 cvs 5029: previous box. Visibility can only be inherited from above.</p>
1.30 cvs 5030:
5031: <p>If it is a numeric attribute's presentation rule, the visibility can be
1.37 cvs 5032: specified by the attribute's name, in which case the value of the attribute
5033: is used.</p>
1.18 cvs 5034: <pre> 'Visibility' ':' NumberInherit
1.1 cvs 5035: NumberInherit = Integer / AttrID / Inheritance .
1.18 cvs 5036: Integer = NUMBER .</pre>
1.30 cvs 5037:
1.18 cvs 5038: <blockquote class="example">
1.30 cvs 5039: <p><strong>Example:</strong></p>
5040:
5041: <p>Suppose that only <tt>Formula</tt> elements should be displayed in the
1.37 cvs 5042: <tt>MathView</tt> view. Then, the default rules should include:</p>
1.30 cvs 5043: <pre>DEFAULT
1.18 cvs 5044: IN MathView Visibility:0;</pre>
1.30 cvs 5045:
1.31 cvs 5046: <p>which makes all elements invisible in the <tt>MathView</tt> view.
1.30 cvs 5047: However, the <tt>Formula</tt> element also has a <tt>Visibility</tt>
5048: rule:</p>
5049: <pre>Formula :
1.18 cvs 5050: IN MathView Visibility:5;</pre>
1.30 cvs 5051:
5052: <p>which makes formulas, and only formulas, visible.</p>
1.18 cvs 5053: </blockquote>
5054: </div>
1.1 cvs 5055:
1.18 cvs 5056: <div class="subsection">
1.37 cvs 5057: <h3><a name="sectc4225" id="sectc4225">Character style properties</a></h3>
1.1 cvs 5058:
1.34 cvs 5059: <p>Four properties are used to determine which characters are used to display
1.37 cvs 5060: text. They are size, font, style, and underlining.</p>
1.1 cvs 5061:
1.18 cvs 5062: <div class="subsubsection">
1.37 cvs 5063: <h4><a name="sectd42251" id="sectd42251">Character size</a></h4>
1.30 cvs 5064:
1.37 cvs 5065: <p>The size property has two effects. First, it is used to specify the actual
1.34 cvs 5066: size and distance units for boxes defined in <a href="#sectc4217">relative
1.37 cvs 5067: units</a>. Second, it defines the size of the characters contained in the
1.34 cvs 5068: box.</p>
1.1 cvs 5069:
1.30 cvs 5070: <p>As a distance or length, the size can be expressed in abstract or absolute
1.37 cvs 5071: units. It can also be inherited. If it is not inherited, it is expressed
5072: simply as an integer followed by the <tt>pt</tt> keyword, which indicates
5073: that the size is expressed in typographer's points. The absence of the
5074: <tt>pt</tt> keyword indicates that it is in abstract units in which the value
5075: 1 represents the smallest size while the value 16 is the largest size. The
5076: relationship between these abstract sizes and the real character sizes is
5077: controlled by a table which can be modified statically or even dynamically
5078: during the execution of the Thot editor.</p>
1.30 cvs 5079:
5080: <p>If the <tt>Size</tt> rule is a numeric attribute's presentation rule, the
1.34 cvs 5081: value of the size property can be specified by the attribute's name, in which
1.30 cvs 5082: case the value of the attribute is used.</p>
5083:
1.37 cvs 5084: <p><strong>Note:</strong> the only unit available for defining an absolute
5085: size is the typographer's point. Centimeters and inches may not be used.</p>
1.30 cvs 5086:
5087: <p>If the size is inherited, the rule must specify the relative from which to
5088: inherit and any percentage or difference from that relative's value. A
5089: percentage is indicated by a <tt>*</tt> followed by the value of the
5090: percentage and a <tt>%</tt>. A difference can be expressed in either
5091: typographer's points or in abstract units and the maximum or minimum size can
1.37 cvs 5092: be specified, but without specifying the unit: it is the same as was
5093: specified for the difference.</p>
1.30 cvs 5094:
5095: <p>In a numeric attribute's presentation rule, the difference in size or the
1.22 cvs 5096: percentage can be indicated by the attribute's name instead of the numeric
1.37 cvs 5097: value, which means that the attribute's value should be used as the
5098: difference or percentage. The attribute can also be used as the minimum or
5099: maximum size for a difference.</p>
1.22 cvs 5100: <pre> 'Size' ':' SizeInherit
5101: SizeInherit = SizeAttr [ 'pt' ] /
5102: Kinship InheritedSize .
5103: InheritedSize ='+' SizeAttr [ 'pt' ]
5104: [ 'Max' MaxSizeAttr ] /
5105: '-' SizeAttr [ 'pt' ]
5106: [ 'Min' MinSizeAttr ] /
5107: '*' PercentSizeAttr '%' /
5108: '=' .
5109: SizeAttr = Size / AttrID .
5110: Size = NUMBER .
5111: MaxSizeAttr = MaxSize / AttrID .
5112: MaxSize = NUMBER .
5113: MinSizeAttr = MinSize / AttrID .
5114: MinSize = NUMBER .
5115: PercentSizeAttr = PercentSize / AttrID .
5116: PercentSize = NUMBER .</pre>
1.30 cvs 5117:
1.18 cvs 5118: <blockquote class="example">
1.30 cvs 5119: <p><strong>Example:</strong></p>
5120:
5121: <p>The rule</p>
5122: <pre>Size : Enclosing - 2 pt Min 7;</pre>
5123:
5124: <p>states that the character size is 2 points less than that of the
5125: enclosing box, but that it may not be less than 7 points, whatever the
5126: enclosing box's value.</p>
5127:
5128: <p>The following rules make the text of a report be displayed with
5129: medium-sized characters (for example, size 5), while the title is displayed
5130: with larger characters and the summary is displayed with smaller
5131: characters:</p>
5132: <pre>Report :
1.1 cvs 5133: Size : 5;
5134: Title :
5135: Size : Enclosing + 2;
5136: Summary :
1.18 cvs 5137: Size : Enclosing - 1;</pre>
1.30 cvs 5138:
5139: <p>Thus, the character sizes in the entire document can be changed by
1.34 cvs 5140: changing the size property of the Report element, while preserving the
1.30 cvs 5141: relationships between the sizes of the different elements.</p>
1.18 cvs 5142: </blockquote>
5143: </div>
5144:
5145: <div class="subsubsection">
1.37 cvs 5146: <h4><a name="sectd42252" id="sectd42252">Font and character style</a></h4>
1.18 cvs 5147:
1.37 cvs 5148: <p>The <tt>Font</tt> rule determines the font family to be used to display
5149: the characters contained in the box, while the <tt>Style</tt> rule determines
5150: their style and the <tt>Weight</tt> rule determines their weight. Thot
1.23 cvs 5151: recognizes three character fonts (Times, Helvetica, and Courier), three
5152: styles: Roman, Italics, and Oblique, and two weights: Normal and Bold.</p>
1.30 cvs 5153:
5154: <p>The font family, style and weight can be specified by a named constant or
1.37 cvs 5155: can be inherited. For the name of the font family only the first character is
1.30 cvs 5156: used.</p>
5157:
5158: <p>Only identical inheritance is allowed: the box takes the same font, style
1.37 cvs 5159: or weight as the box from which it inherits. This is indicated by an equals
1.23 cvs 5160: sign after the kinship specification.</p>
5161: <pre> 'Font' ':' NameInherit /
5162: 'Style' ':' StyleInherit /
5163: 'Weight' ':' WeightInherit /
5164:
5165: NameInherit = Kinship '=' / FontName .
5166: FontName = NAME .
5167: StyleInherit = Kinship '=' /
5168: 'Roman' / 'Italics' / 'Oblique' .
5169: WeightInherit = Kinship '=' /
5170: 'Normal' / 'Bold' .</pre>
1.30 cvs 5171:
1.18 cvs 5172: <blockquote class="example">
1.30 cvs 5173: <p><strong>Example:</strong></p>
5174:
5175: <p>To specify that the summary uses the font family of the rest of the
5176: document, but in the italic style, the following rules are used:</p>
5177: <pre>Summary :
1.1 cvs 5178: BEGIN
5179: Font : Enclosing =;
5180: Style : Italics;
1.18 cvs 5181: END;</pre>
5182: </blockquote>
5183: </div>
5184:
5185: <div class="subsubsection">
1.37 cvs 5186: <h4><a name="sectd42253" id="sectd42253">Underlining</a></h4>
1.18 cvs 5187:
1.30 cvs 5188: <p>The <tt>Underline</tt> rule is used to specify if the characters contained
1.37 cvs 5189: in a box should have lines drawn on or near them. There are four underlining
1.18 cvs 5190: styles: <tt>Underlined</tt>, <tt>Overlined</tt>, <tt>CrossedOut</tt>, and
1.37 cvs 5191: <tt>NoUnderline</tt>. The <tt>Thickness</tt> rule specifies the thickness of
1.18 cvs 5192: the line, <tt>Thin</tt> or <tt>Thick</tt>.</p>
1.30 cvs 5193:
5194: <p>As with font family and style, only identical inheritance is allowed: the
1.37 cvs 5195: box has the same underlining type as the box from which it inherits the
5196: value. This is indicated by an equals sign after the kinship
5197: specification.</p>
1.18 cvs 5198: <pre> 'Underline' ':' UnderLineInherit /
1.1 cvs 5199: 'Thickness' ':' ThicknessInherit /
5200:
5201: UnderLineInherit = Kinship '=' / 'NoUnderline' /
5202: 'Underlined' /
5203: 'Overlined' / 'CrossedOut' .
1.18 cvs 5204: ThicknessInherit = Kinship '=' / 'Thick' / 'Thin' .</pre>
5205: </div>
5206: </div>
5207:
5208: <div class="subsection">
1.37 cvs 5209: <h3><a name="sectc4226" id="sectc4226">Stacking order</a></h3>
1.18 cvs 5210:
1.30 cvs 5211: <p>The <tt>Depth</tt> rule is used to define the stacking order of terminal
1.37 cvs 5212: boxes when multiple boxes at least partially overlap. This rule defines how
5213: the depth property, which is zero or a positive integer, is calculated. The
5214: depth property has a value for all boxes. For terminal boxes in the structure
1.34 cvs 5215: and for presentation boxes, the depth value is used during display and
5216: printing: the boxes with the lowest value overlap those with higher depths.
1.37 cvs 5217: For non-terminal boxes, the depth is not interpreted during display, but it
5218: is used to calculate the depth of terminal boxes by inheritance.</p>
1.30 cvs 5219:
5220: <p>Like most other rules, the depth rule is defined in the <a
1.37 cvs 5221: href="#sectc427">default rules</a> of each presentation schema. Thus, there
1.18 cvs 5222: is always a depth value, even when it is not necessary because there is no
1.37 cvs 5223: overlapping. To avoid useless operations, a zero value can be given to the
1.34 cvs 5224: depth property, which signifies that overlapping is never a problem.</p>
1.30 cvs 5225:
5226: <p>The depth rule has the same form as the <a href="#sectc4224">visibility
1.18 cvs 5227: rule</a>. It can be defined by inheritance or by a constant numeric value.
5228: When the rule is attached to a numeric attribute, it can take the value of
5229: that attribute.</p>
5230: <pre> 'Depth' ':' NumberInherit</pre>
1.30 cvs 5231:
1.18 cvs 5232: <blockquote class="example">
1.30 cvs 5233: <p><strong>Example:</strong></p>
5234:
5235: <p>For a purely textual document, in which overlapping never poses a
5236: problem, a single default <tt>Depth</tt> rule in the presentation schema is
5237: sufficient:</p>
5238: <pre>DEFAULT
1.1 cvs 5239: Depth : 0;
1.18 cvs 5240: ...</pre>
1.30 cvs 5241:
5242: <p>To make the text of examples appear on a light blue background, a
5243: presentation box is defined:</p>
5244: <pre>BOXES
1.1 cvs 5245: BlueBG :
5246: BEGIN
5247: Content : Graphics 'R';
5248: Background : LightBlue3;
5249: FillPattern: backgroundcolor;
5250: Depth : 2;
5251: ...
1.18 cvs 5252: END;</pre>
1.30 cvs 5253:
5254: <p>and is created by the <tt>Example</tt> element, which has the rules:</p>
5255: <pre>RULES
1.1 cvs 5256: Example :
5257: BEGIN
5258: CreateFirst (BlueBG);
5259: Depth : 1;
5260: ...
1.18 cvs 5261: END;</pre>
1.30 cvs 5262:
5263: <p>In this way, the text of an example (if it inherits its depth from its
5264: ancestor) will be superimposed on a light blue background, and not the
5265: reverse).</p>
1.18 cvs 5266: </blockquote>
5267: </div>
5268:
5269: <div class="subsection">
1.37 cvs 5270: <h3><a name="sectc4227" id="sectc4227">Line style</a></h3>
1.18 cvs 5271:
1.30 cvs 5272: <p>The <tt>LineStyle</tt> rule determines the style of line which should be
5273: used to draw all the elements contained in the box and the box itself, if it
1.37 cvs 5274: has a <a href="#sectc4230a"><tt>ShowBox</tt> rule</a>. The line style can be
1.18 cvs 5275: indicated by a name (<tt>Solid</tt>, <tt>Dashed</tt>, <tt>Dotted</tt>) or it
1.37 cvs 5276: can be inherited. All elements of the graphic base type are affected by this
1.1 cvs 5277: rule, but it can be attached to any box and transmitted by inheritance to the
1.37 cvs 5278: graphic elements. The border of elements having a <a
1.18 cvs 5279: href="#sectc4230a"><tt>ShowBox</tt> rule</a> is drawn according to the line
5280: style specified by this rule.</p>
1.30 cvs 5281:
1.37 cvs 5282: <p>Only identical inheritance is allowed: the box takes the same line style
5283: as the box from which it inherits. This is indicated by an equals sign after
5284: the kinship specification.</p>
1.18 cvs 5285: <pre> 'LineStyle' ':' LineStyleInherit
1.1 cvs 5286: LineStyleInherit = Kinship '=' /
1.18 cvs 5287: 'Solid' / 'Dashed' / 'Dotted' .</pre>
1.30 cvs 5288:
1.18 cvs 5289: <blockquote class="example">
1.30 cvs 5290: <p><strong>Example:</strong></p>
5291:
1.37 cvs 5292: <p>To specify that, in Figures, the graphical parts should be drawn in
5293: solid lines, the Figure element is given a rule using the <tt>Solid</tt>
5294: name:</p>
1.30 cvs 5295: <pre>Figure :
1.18 cvs 5296: LineStyle : Solid;</pre>
1.30 cvs 5297:
5298: <p>and the elements composing figures are given an inheritance rule:</p>
5299: <pre> LineStyle : Enclosing =;</pre>
1.18 cvs 5300: </blockquote>
5301: </div>
5302:
5303: <div class="subsection">
1.37 cvs 5304: <h3><a name="sectc4228" id="sectc4228">Line thickness</a></h3>
1.18 cvs 5305:
1.37 cvs 5306: <p>The <tt>LineWeight</tt> rule determines the thickness of the lines of all
1.1 cvs 5307: graphical elements which appear in the box, no matter what their line style.
1.37 cvs 5308: Line thickness can be specified by a constant value or by inheritance. A
5309: constant value is a positive number followed by an optional unit
5310: specification (which is absent when using relative units). All available <a
5311: href="#sectc4217">distance units</a> can be used. Line thickness is expressed
1.18 cvs 5312: in the same way as <a href="#sectd42221">line spacing</a>.</p>
5313: <pre> 'LineWeight' ':' DistOrInherit</pre>
1.30 cvs 5314:
1.37 cvs 5315: <p>All elements of the graphic base type are affected by this rule, but it
5316: can be attached to any box and transmitted by inheritance to the graphic
5317: elements. The border of element having a <a
5318: href="#sectc4230a"><tt>ShowBox</tt> rule</a> is also drawn according to the
5319: thickness specified by this rule.</p>
1.30 cvs 5320:
1.18 cvs 5321: <blockquote class="example">
1.30 cvs 5322: <p><strong>Example:</strong></p>
5323:
5324: <p>To specify that, in Figures, the graphical parts should be drawn with
5325: lines 0.3 pt thick, the Figure element is given this rule:</p>
5326: <pre>Figure :
1.18 cvs 5327: LineWeight : 0.3 pt;</pre>
1.30 cvs 5328:
5329: <p>and the elements composing figures are given an inheritance rule:</p>
5330: <pre> LineWeight : Enclosing =;</pre>
1.18 cvs 5331: </blockquote>
5332: </div>
5333:
5334: <div class="subsection">
1.37 cvs 5335: <h3><a name="sectc4229" id="sectc4229">Fill pattern</a></h3>
1.18 cvs 5336:
1.30 cvs 5337: <p>The <tt>FillPattern</tt> rule determines the pattern used to fill closed
1.37 cvs 5338: graphical elements (circles, rectangles, etc.) which appear in the box. This
1.18 cvs 5339: rule also specifies the pattern used to fill the box associated with elements
1.37 cvs 5340: having a <a href="#sectc4230a"><tt>ShowBox</tt> rule</a><a>. This pattern can
5341: be indicated by a named constant or by inheritance. The named constant
5342: identifies one of the patterns available in Thot. The names of the available
1.18 cvs 5343: patterns are: nopattern, foregroundcolor, backgroundcolor, gray1, gray2,
5344: gray3, gray4, gray5, gray6, gray7, horiz1, horiz2, horiz3, vert1, vert2,
1.37 cvs 5345: vert3, left1, left2, left3, right1, right2, right3, square1, square2,
5346: square3, lozenge, brick, tile, sea, basket.</a></p>
1.30 cvs 5347:
5348: <p>Like the other rules peculiar to graphics, <tt>LineStyle</tt> and
1.18 cvs 5349: <tt>LineWeight</tt>, only elements of the graphic base type are affected by
5350: the <tt>FillPattern</tt> rule, but the rule can be attached to any box and
1.37 cvs 5351: transmitted by inheritance to the graphic elements. As with the other rules
1.18 cvs 5352: specific to graphics, only identical inheritance is allowed.</p>
1.30 cvs 5353:
5354: <p>The <tt>FillPattern</tt> rule can also be used to determine whether or not
1.37 cvs 5355: text characters, symbols and pictures should be colored. For these element
1.12 cvs 5356: types (text, symbols, and pictures), the only valid values are
1.18 cvs 5357: <tt>nopattern</tt>, <tt>foregroundcolor</tt>, and <tt>backgroundcolor</tt>.
5358: When <tt>FillPattern</tt> has the value <tt>backgroundcolor</tt>, text
5359: characters, symbols, and bitmaps are given the color specified by the <a
5360: href="#sectc4230"><tt>Background</tt> rule</a> which applies to these
1.37 cvs 5361: elements. When <tt>FillPattern</tt> has the value <tt>foregroundcolor</tt>,
1.18 cvs 5362: these same elements are given the color specified by the <a
5363: href="#sectc4230"><tt>Foreground</tt> rule</a> which applies to these
1.37 cvs 5364: elements. In all other case, text characters are not colored.</p>
1.18 cvs 5365: <pre> 'FillPattern' ':' NameInherit</pre>
1.30 cvs 5366:
1.18 cvs 5367: <blockquote class="example">
1.30 cvs 5368: <p><strong>Example:</strong></p>
5369:
5370: <p>To specify that, in Figures, the closed graphical elements should be
5371: filled with a pattern resembling a brick wall, the Figure element is given
5372: this rule:</p>
5373: <pre>Figure :
1.18 cvs 5374: FillPattern : brick;</pre>
1.30 cvs 5375:
5376: <p>and the elements composing figures are given an inheritance rule:</p>
5377: <pre> FillPattern : Enclosing =;</pre>
1.18 cvs 5378: </blockquote>
5379: </div>
5380:
5381: <div class="subsection">
1.37 cvs 5382: <h3><a name="sectc4230" id="sectc4230">Colors</a></h3>
1.18 cvs 5383:
1.30 cvs 5384: <p>The <tt>Foreground</tt> and <tt>Background</tt> rules determine the
1.37 cvs 5385: foreground and background colors of the base elements which appear in the
5386: box. They also control the color of boxes associated with elements having a
5387: <a href="#sectc4230a"><tt>ShowBox</tt> rule</a>. These colors can be
5388: specified with a named constant or by inheritance. The named constants
5389: specify one of the available colors in Thot. The available color names can be
5390: found in the file <tt>thot.color</tt>. In addition to those names, you can
5391: use the keyword <code>Transparent</code>, to not draw anything.</p>
5392:
5393: <p>The color rules affect the same way all base elements and elements having
5394: a <a href="#sectc4230a"><tt>ShowBox</tt> rule</a>, no matter what their type
5395: (text, graphics, pictures, symbols). The color rules can be associated with
1.30 cvs 5396: any box and can be transmitted by inheritance to the base elements or the
1.37 cvs 5397: elements having a <a href="#sectc4230a"><tt>ShowBox</tt> rule</a>. Like the
1.30 cvs 5398: preceding rules, only inheritance of the same value is allowed.</p>
5399: <pre> 'Foreground' ':' Color
5400: 'Background' ':' Color
5401: Color = 'Transparent' / Link '=' / FontColorName .</pre>
5402:
5403: <p><strong>Note:</strong> text colors only appear for text elements whose <a
1.18 cvs 5404: href="#sectc4229">fill pattern</a> does not prevent the use of color.</p>
1.30 cvs 5405:
1.18 cvs 5406: <blockquote class="example">
1.30 cvs 5407: <p><strong>Example:</strong></p>
5408:
5409: <p>To specify that, in Figures, everything must be drawn in blue on a
5410: background of yellow, the Figure element is given these rules:</p>
5411: <pre>Figure :
1.1 cvs 5412: BEGIN
5413: Foreground : Blue;
5414: Background : Yellow;
5415: Fillpattern : backgroundcolor;
1.18 cvs 5416: END;</pre>
1.30 cvs 5417:
5418: <p>and the elements composing figures are given inheritance rules:</p>
5419: <pre> Foreground : Enclosing =;
1.1 cvs 5420: Background : Enclosing =;
1.18 cvs 5421: FillPattern : Enclosing =;</pre>
5422: </blockquote>
5423: </div>
5424:
5425: <div class="subsection">
1.37 cvs 5426: <h3><a name="sectc4230a" id="sectc4230a">Background color and border</a></h3>
1.18 cvs 5427:
1.30 cvs 5428: <p>Boxes associated with structural elements are normally not visible, but it
1.37 cvs 5429: is possible to draw their border and/or to paint their area when it is
5430: needed. This is achieved by associating the <tt>ShowBox</tt> rule with the
5431: concerned element. This rule has no parameter and no value. It is simply
5432: written <tt>Showbox;</tt>. It is not inherited nor transmitted to any other
5433: element. It applies only to the element with which it is associated.</p>
1.18 cvs 5434: <pre> 'ShowBox'</pre>
1.30 cvs 5435:
5436: <p>When an element has a <tt>ShowBox</tt> rule, the border is drawn only if
1.37 cvs 5437: the <tt>LineWeight</tt> rule that applies to that element has a non-zero
5438: value (this value can be inherited). The color, style and thickness of the
5439: border are defined by the <tt>Foreground</tt>, <tt>LineStyle</tt>, and
1.18 cvs 5440: <tt>LineWeight</tt> rules that apply to the element.</p>
1.30 cvs 5441:
1.37 cvs 5442: <p>When an element has a <tt>ShowBox</tt> rule, the background of this
5443: element is paint only if the value of the <tt>FillPattern</tt> rule that
5444: applies to that element is not <tt>nopattern</tt>. The pattern and color(s)
5445: of the background are defined by the <tt>FillPattern</tt>,
5446: <tt>Background</tt>, and <tt>Foreground</tt> rules that apply to the
5447: element.</p>
1.18 cvs 5448: </div>
5449:
5450: <div class="subsection">
1.37 cvs 5451: <h3><a name="sectc4230b" id="sectc4230b">Background pictures</a></h3>
1.18 cvs 5452:
1.30 cvs 5453: <p>The <tt>BackgroundPicture</tt> rule allows to display a picture as the
1.37 cvs 5454: background of an element. It has a single parameter, the file name of the
5455: picture. This is a string delimited by single quotes. If the first character
1.18 cvs 5456: in this string is '/', it is considered as an absolute path, otherwise the
1.37 cvs 5457: file is searched for along the schema directory path. This file may contain a
1.18 cvs 5458: picture in any format accepted by Thot (xbm, xpm, gif, jpeg, png, etc.)</p>
1.30 cvs 5459:
1.37 cvs 5460: <p>The <tt>BackgroundPicture</tt> and <tt>PictureMode</tt> rules apply only
5461: to the element with which they are associated. They are not inherited nor
1.18 cvs 5462: transmitted to children elements.</p>
1.30 cvs 5463:
5464: <p>The background picture has not always the same size as the element's box.
1.37 cvs 5465: There are diffrent ways to fill the element box with the picture. This is
1.18 cvs 5466: specified by the <tt>PictureMode</tt> rule, which should be associated to the
1.37 cvs 5467: same element. This rule may take one of the following values:</p>
1.18 cvs 5468: <dl>
1.30 cvs 5469: <dt><tt>NormalSize</tt></dt>
5470: <dd>The picture is centered in the box, and clipped if it is too
5471: large.</dd>
5472: <dt><tt>Scale</tt></dt>
5473: <dd>The picture is zoomed to fit the box size.</dd>
5474: <dt><tt>RepeatX</tt></dt>
5475: <dd>The picture is repeated horizontally to fit the box width.</dd>
5476: <dt><tt>RepeatY</tt></dt>
5477: <dd>The picture is repeated vertically to fit the box height.</dd>
5478: <dt><tt>RepeatXY</tt></dt>
5479: <dd>The picture is repeated both horizontally and vertically to fill the
5480: box.</dd>
1.18 cvs 5481: </dl>
1.30 cvs 5482:
5483: <p>If an element has a <tt>BackgroundPicture</tt> rule and no
1.18 cvs 5484: <tt>PictureMode</tt> rule, the <tt>NormalSize</tt> value is assumed.</p>
5485: <pre> 'BackgroundPicture' ':' FileName /
1.13 cvs 5486: 'PictureMode' ':' PictMode .
5487:
5488: FileName = STRING .
1.18 cvs 5489: PictMode = 'NormalSize' / 'Scale' / 'RepeatXY' / 'RepeatX' / 'RepeatY' .</pre>
1.30 cvs 5490:
1.37 cvs 5491: <p>The <tt>BackgroundPicture</tt> and <tt>PictureMode</tt> rules apply only
5492: to the element with which they are associated. They are not inherited nor
1.18 cvs 5493: transmitted to children elements.</p>
5494: </div>
1.13 cvs 5495:
1.18 cvs 5496: <div class="subsection">
1.37 cvs 5497: <h3><a name="sectc4231" id="sectc4231">Presentation box content</a></h3>
1.1 cvs 5498:
1.37 cvs 5499: <p>The <tt>Content</tt> rule applies to presentation boxes. It indicates the
5500: content given to a box. This content is either a variable's value or a
5501: constant value.</p>
1.30 cvs 5502:
5503: <p>If the content is a constant, it can be specified, as in a variable
1.18 cvs 5504: declaration, either by the name of a constant declared in the <tt>CONST</tt>
1.1 cvs 5505: section or by direct specification of the type and value of the box's
1.18 cvs 5506: content.</p>
1.30 cvs 5507:
5508: <p>Similarly, if it is a variable, the name of a variable declared in
1.18 cvs 5509: <tt>VAR</tt> section can be given or the variable may be defined within
1.37 cvs 5510: parentheses. The content inside the parentheses has the same syntax as a <a
1.18 cvs 5511: href="#sectc426">variable declaration</a>.</p>
5512: <pre> 'Content' ':' VarConst
1.1 cvs 5513: VarConst = ConstID / ConstType ConstValue /
1.38 ! cvs 5514: VarID / '(' FunctionSeq ')' .</pre>
1.30 cvs 5515:
5516: <p>A presentation box can have only one <tt>Content</tt> rule, which means
1.37 cvs 5517: that the content of a presentation box cannot vary from view to view.
5518: However, such an effect can be achieved by creating several presentation
5519: boxes, each with different content and visible in different views.</p>
5520:
5521: <p>The <tt>Content</tt> rule also applies to elements defined as references
5522: in the structure schema. In this case, the content defined by the rule must
5523: be a constant. It is this content which appears on the screen or paper to
5524: represent references of the type to which the rule applies. A reference can
1.18 cvs 5525: have a <tt>Content</tt> rule or a <a href="#sectc4234"><tt>Copy</tt> rule</a>
1.37 cvs 5526: for each view. If neither of these rules appears, the reference is displayed
1.18 cvs 5527: as <tt>[*]</tt>, which is equivalent to the rule:</p>
5528: <pre> Content: Text '[*]';</pre>
1.30 cvs 5529:
1.18 cvs 5530: <blockquote class="example">
1.30 cvs 5531: <p><strong>Example:</strong></p>
5532:
5533: <p>The content of the presentation box created to make the chapter number
5534: and section number appear before each section title can be defined by:</p>
5535: <pre>BOXES
1.1 cvs 5536: SectionNumBox :
5537: BEGIN
5538: Content : NumSection;
5539: ...
1.18 cvs 5540: END;</pre>
1.30 cvs 5541:
5542: <p>if the <tt>NumSection</tt> variable has been defined in the variable
1.37 cvs 5543: definition section of the presentation schema. Otherwise the
1.30 cvs 5544: <tt>Content</tt> would be written:</p>
5545: <pre>BOXES
1.1 cvs 5546: SectionNumBox :
5547: BEGIN
5548: Content : (VALUE (ChapterCtr, Roman) TEXT '.'
5549: VALUE (SectionCtr, Arabic));
5550: ...
1.18 cvs 5551: END;</pre>
5552: </blockquote>
5553: </div>
1.1 cvs 5554:
1.18 cvs 5555: <div class="subsection">
1.37 cvs 5556: <h3><a name="sectc4232" id="sectc4232">Presentation box creation</a></h3>
1.1 cvs 5557:
1.37 cvs 5558: <p>A creation rule specifies that a presentation box should be created when
5559: an element of the type to which the rule is attached appears in the
5560: document.</p>
1.30 cvs 5561:
5562: <p>A keyword specifies the position, relative to the creating box, at which
5563: the created box will be placed in the structure:</p>
1.18 cvs 5564: <dl>
1.30 cvs 5565: <dt><tt>CreateFirst</tt></dt>
5566: <dd>specifies that the box should be created as the first box of the next
5567: lower level, before any already existing boxes, and only if the
5568: beginning of the creating element is visible;</dd>
5569: <dt><tt>CreateLast</tt></dt>
5570: <dd>specifies that the box should be created as the last box of the next
5571: lower level, after any existing boxes, and only if the end of the
5572: creating element is visible;</dd>
5573: <dt><tt>CreateBefore</tt></dt>
5574: <dd>specifies that the box should be created before the creating box, on
5575: the same level as the creating box, and only if the beginning of the
5576: creating element is visible;</dd>
5577: <dt><tt>CreateAfter</tt></dt>
5578: <dd>specifies that the box should be created after the creating box, on
5579: the same level as the creating box, and only if the beginning of the
5580: creating element is visible;</dd>
5581: <dt><tt>CreateEnclosing</tt></dt>
1.37 cvs 5582: <dd>specifies that the box should be created at the upper level
5583: relatively to the creating box, and that it must contain that creating
5584: box and all presentation boxes created by the same creating box.</dd>
1.18 cvs 5585: </dl>
1.30 cvs 5586:
5587: <p>This keyword can be followed by the <tt>Repeated</tt> keyword to indicate
5588: that the box must be created for each part of the creating element. These
5589: parts result from the division of the element by page breaks or column
1.37 cvs 5590: changes. If the <tt>Repeated</tt> keyword is missing, the box is only created
1.30 cvs 5591: for the first part of the creating element (<tt>CreateFirst</tt> and
1.18 cvs 5592: <tt>CreateBefore</tt> rules) or for the last part (<tt>CreateLast</tt> and
5593: <tt>CreateAfter</tt> rules).</p>
1.30 cvs 5594:
5595: <p>The type of presentation to be created is specified at the end of the rule
1.18 cvs 5596: between parentheses.</p>
1.30 cvs 5597:
5598: <p>Creation rules cannot appear in the <a href="#sectc427">default
1.37 cvs 5599: presentation rules</a>. The boxes being created should have a
1.30 cvs 5600: <tt>Content</tt> rule which indicates their <a
5601: href="#sectc4231">content</a>.</p>
5602:
5603: <p>Creation rules can only appear in the block of rules for the primary view;
1.1 cvs 5604: creation is provoked by a document element for all views. However, for each
1.37 cvs 5605: view, the presentation box is only created if the creating element is itself
5606: a box in the view. Moreover, the visibility property of the presentation box
5607: can be adjusted to control the creation of the box on a view-by-view
5608: basis.</p>
1.18 cvs 5609: <pre> Creation '(' BoxID ')'
1.1 cvs 5610: Creation = Create [ 'Repeated' ] .
5611: Create ='CreateFirst' / 'CreateLast' /
5612: 'CreateBefore' / 'CreateAfter' /
1.18 cvs 5613: 'CreateEnclosing' .</pre>
1.30 cvs 5614:
1.18 cvs 5615: <blockquote class="example">
1.30 cvs 5616: <p><strong>Example:</strong></p>
5617:
5618: <p>Let us define an object type, called Table, which is composed of a
5619: sequence of columns, all having the same fixed width, where the columns are
1.37 cvs 5620: separated by vertical lines. There is a line to the left of the first
5621: column and one to the right of the last. Each column has a variable number
1.31 cvs 5622: of cells, placed one on top of the other and separated by horizontal lines.
5623: There are no horizontal lines above the first cell or below the last cell.
1.37 cvs 5624: The text contained in each cell is broken into lines and these lines are
1.30 cvs 5625: centered horizontally in the cell. The logical structure of this object is
5626: defined by:</p>
5627: <pre>Table = LIST OF (Column);
1.18 cvs 5628: Column = LIST OF (Cell = Text);</pre>
5629:
1.30 cvs 5630: <div class="figure">
1.37 cvs 5631: <hr />
1.30 cvs 5632: <pre>| | | |
1.1 cvs 5633: | xx xxxx xxxx |x xxxx xxx xxxxx| x xxx x xxx |
5634: | xxx xxx xxxx x | x xx x xxx | xxxxx xxxx xx |
5635: | xxxxx xxxx |----------------| xxx xxxxx x |
5636: | xxxxx xxx xxxx | xxxx xx xx xxx | xx xx |
5637: | xxx xxxx x xxx | xxxx x xxx x |---------------|
5638: |----------------| xxx xxxx xxxxx | xxxxx xxxxx |
5639: | xxx xxx xxxxxx |----------------| xxx xxxx xxxx |
5640: | xxxx xxxx xx | xxxx xx x xx | xxx xx x xx |
5641: |----------------| xxx xxxxx xxxx | xxxx xxxx xxx |
5642: | xxxxx xxx xxxx | xxxx xx x xx | xxxxx xxx |
1.18 cvs 5643: |xxxx xx x xxxxxx| xxxx xx xxxxxx | xxxxx xxxxx |</pre>
1.19 cvs 5644:
1.37 cvs 5645: <p align="center"><em><a name="table" id="table">The design of a
5646: table</a></em></p>
5647: <hr />
1.30 cvs 5648: </div>
5649:
5650: <p>The presentation of the table should resemble the design of the above <a
1.37 cvs 5651: href="#table">figure</a>. It is defined by the following presentation
1.30 cvs 5652: schema fragment:</p>
5653: <pre>BOXES
1.1 cvs 5654: VertLine : BEGIN
5655: Width : 0.3 cm;
5656: Height : Enclosing . Height;
5657: VertPos : Top = Enclosing . Top;
5658: HorizPos : Left = Previous . Right;
5659: Content : Graphics 'v';
5660: END;
5661:
5662: HorizLine: BEGIN
5663: Width : Enclosing . Width;
5664: Height : 0.3 cm;
5665: VertPos : Top = Previous . Bottom;
5666: HorizPos : Left = Enclosing . Left;
5667: Content : Graphics 'h';
5668: END;
5669:
5670: RULES
1.6 cvs 5671: Column : BEGIN
5672: CreateBefore (VertLine);
5673: IF LAST CreateAfter (VertLine);
5674: Width : 2.8 cm;
5675: Height : Enclosed . Height;
5676: VertPos : Top = Enclosing . Top;
5677: HorizPos : Left = Previous . Right;
5678: END;
5679:
5680: Cell : BEGIN
5681: IF NOT FIRST CreateBefore (HorizLine);
5682: Width : Enclosing . Width;
5683: Height : Enclosed . Height;
5684: VertPos : Top = Previous . Bottom;
5685: HorizPos : Left = Enclosing . Left;
5686: Line;
5687: Adjust : VMiddle;
1.18 cvs 5688: END;</pre>
1.30 cvs 5689:
5690: <p>It is useful to note that the horizontal position rule of the first
5691: vertical line will not be applied, since there is no preceding box. In this
5692: case, the box is simply placed on the left side of the enclosing box.</p>
1.18 cvs 5693: </blockquote>
5694: </div>
5695:
5696: <div class="subsection">
1.37 cvs 5697: <h3><a name="sectc4233" id="sectc4233">Page layout</a></h3>
1.18 cvs 5698:
1.30 cvs 5699: <p>The page models specified in the <tt>Page</tt> rule are defined by boxes
1.37 cvs 5700: declared in the <tt>BOXES</tt> section of the presentation schema. Pages are
1.1 cvs 5701: not described as frames which will be filled by the document's text, but as
5702: element are inserted in the flow of the document and which mark the page
1.37 cvs 5703: breaks. Each of these page break elements contains presentation boxes which
1.1 cvs 5704: represent the footer boxes of a page followed by header boxes of the next
1.37 cvs 5705: page. The page box itself is the simple line which separates two pages on the
5706: screen. Both the footer and header boxes placed themselves with respect to
1.1 cvs 5707: this page box, with the footer being placed above it and the header boxes
1.18 cvs 5708: being placed above it.</p>
1.30 cvs 5709:
5710: <p>The boxes created by a page box are headers and footers and can only place
1.1 cvs 5711: themselves vertically with respect to the page box itself (which is in fact
1.37 cvs 5712: the separation between two pages). Besides, it is their vertical position
5713: rule which determines whether they are header or footer boxes. Header and
1.1 cvs 5714: footer boxes must have an explicit vertical position rule (they must not use
1.18 cvs 5715: the default rule).</p>
1.30 cvs 5716:
5717: <p>Footer boxes must have an absolute height or inherit the height of their
1.18 cvs 5718: contents:</p>
5719: <pre>Height : Enclosed . Height;</pre>
1.30 cvs 5720:
5721: <p>A page box must have height and width rules and these two rules must be
1.1 cvs 5722: specified with constant values, expressed in centimeters, inches, or
1.37 cvs 5723: typographer's points. These two rules are interpreted in a special way for
5724: page boxes: they determine the width of the page and the vertical distance
1.1 cvs 5725: between two page separators, which is the height of the page and its header
1.18 cvs 5726: and footer together.</p>
1.30 cvs 5727:
5728: <p>A page box should also have vertical and horizontal position rules and
5729: these two rules should specify the position on the sheet of paper of the
1.37 cvs 5730: rectangle enclosing the page's contents. These two rules must position the
1.30 cvs 5731: upper left corner of the enclosing rectangle in relation to the upper left
1.37 cvs 5732: corner of the sheet of paper, considered to be the enclosing element. In both
1.30 cvs 5733: rules, distances must be expressed in fixed units: centimeters (<tt>cm</tt>),
1.37 cvs 5734: inches (<tt>in</tt>), or typographer's points (<tt>pt</tt>). Thus, rules
1.30 cvs 5735: similar to the following should be found in the rules for a page box:</p>
1.18 cvs 5736: <pre>BOXES
1.1 cvs 5737: ThePage :
5738: BEGIN
5739: VertPos : Top = Enclosing . Top + 3 cm;
5740: HorizPos : Left = Enclosing . Left + 2.5 cm;
5741: Width : 16 cm;
5742: Height : 22.5 cm;
1.18 cvs 5743: END;</pre>
1.30 cvs 5744:
5745: <p>When a document must be page broken, the page models to be constructed are
1.18 cvs 5746: defined in the <tt>BOXES</tt> section of the presentation schema by declaring
1.37 cvs 5747: page boxes and header and footer boxes. Also, the <tt>Page</tt> rule is used
5748: to specify to which parts of the document and to which views each model
5749: should be applied.</p>
1.30 cvs 5750:
5751: <p>The <tt>Page</tt> rule has only one parameter, given between parentheses
1.37 cvs 5752: after the <tt>Page</tt> keyword. This parameter is the name of the box which
5753: must serve as the model for page construction. When a <tt>Page</tt> rule is
1.1 cvs 5754: attached to an element type, each time such an element appears in a document,
5755: a page break takes place and the page model indicated in the rule is applied
5756: to all following pages, until reaching the next element which has a
1.18 cvs 5757: <tt>Page</tt> rule.</p>
1.30 cvs 5758:
5759: <p>The <tt>Page</tt> rule applies to only one view; if it appears in the
1.37 cvs 5760: primary view's block of rules, a <tt>Page</tt> rule applies only to that
5761: view. Thus, different page models can be defined for the full document and
5762: for its table of contents, which is another view of the same document. Some
5763: views can be specified with pages, and other views of the same document can
5764: be specified without pages.</p>
1.18 cvs 5765: <pre> 'Page' '(' BoxID ')'</pre>
5766: </div>
5767:
5768: <div class="subsection">
1.37 cvs 5769: <h3><a name="sectc4234" id="sectc4234">Box copies</a></h3>
1.18 cvs 5770:
1.30 cvs 5771: <p>The <tt>Copy</tt> rule can be used for an element which is defined as a
1.37 cvs 5772: reference in the structure schema. In this case, the rule specifies, between
1.18 cvs 5773: parenthesis, the name of the box (declared in the <tt>BOXES</tt> section)
1.1 cvs 5774: which must be produced when this reference appears in the structure of a
1.37 cvs 5775: document. The box produced is a copy (same contents, but possible different
1.1 cvs 5776: presentation) of the box type indicated by the parameter between parentheses,
1.37 cvs 5777: and which is in the element designated by the reference. The name of a box
1.1 cvs 5778: can be replaced by type name. Then what is copied is the contents of the
1.18 cvs 5779: element of this type which is inside the referenced element.</p>
1.30 cvs 5780:
1.37 cvs 5781: <p>Whether a box name or type name is given, it may be followed by the name
5782: of a structure schema between parentheses. This signifies that the box or
5783: type is defined in the indicated structure schema and not in the structure
5784: schema with which the rule's presentation schema is associated.</p>
1.30 cvs 5785:
1.37 cvs 5786: <p>The <tt>Copy</tt> rule can also be applied to a presentation box. If the
1.1 cvs 5787: presentation box was created by a reference attribute, the rule is applied as
5788: in the case of a reference element: the contents of the box having the
1.18 cvs 5789: <tt>Copy</tt> rule are based on the element designated by the reference
1.37 cvs 5790: attribute. For other presentation boxes, the <tt>Copy</tt> rule takes a type
1.1 cvs 5791: name parameter which can be followed, between parentheses, by the name of the
5792: structure schema in which the type is defined, if it is not defined in the
1.37 cvs 5793: same schema. The contents of the box which has this rule are a copy of the
5794: element of this type which is in the element creating the presentation box,
5795: or by default, the box of this type which precedes the presentation box. This
5796: last facility is used, for example, to define the running titles in headers
5797: or footers.</p>
1.18 cvs 5798: <pre> 'Copy' '(' BoxTypeToCopy ')' .
1.1 cvs 5799: BoxTypeToCopy = BoxID [ ExtStruct ] /
1.6 cvs 5800: ElemID [ ExtStruct ] .
1.18 cvs 5801: ExtStruct = '(' ElemID ')' .</pre>
1.30 cvs 5802:
5803: <p>Like the creation rules, the <tt>Copy</tt> rule cannot appear in the <a
1.37 cvs 5804: href="#sectc427">default presentation rules</a>. Moreover, this rule can only
1.18 cvs 5805: appear in the primary view's block of rules; the copy rule is applied to all
5806: views.</p>
1.30 cvs 5807:
1.18 cvs 5808: <blockquote class="example">
1.30 cvs 5809: <p><strong>Example:</strong></p>
5810:
5811: <p>If the following definitions are in the structure schema:</p>
5812: <pre>Body = LIST OF (Chapter =
1.1 cvs 5813: BEGIN
5814: ChapterTitle = Text;
5815: ChapterBody = SectionSeq;
5816: END);
1.18 cvs 5817: RefChapter = REFERENCE (Chapter);</pre>
1.30 cvs 5818:
5819: <p>then the following presentation rules (among many other rules in the
5820: presentation schema) can be specified:</p>
5821: <pre>COUNTERS
1.1 cvs 5822: ChapterCtr : RANK OF Chapter;
5823: BOXES
5824: ChapterNumber :
5825: BEGIN
5826: Content : (VALUE (ChapterCtr, URoman));
5827: ...
5828: END;
5829: RULES
5830: Chapter :
5831: BEGIN
5832: CreateFirst (ChapterNumber);
5833: ...
5834: END;
5835: RefChapter :
5836: BEGIN
5837: Copy (ChapterNumber);
5838: ...
1.18 cvs 5839: END;</pre>
1.30 cvs 5840:
5841: <p>which makes the number of the chapter designated by the reference appear
5842: in uppercase roman numerals, in place of the reference to a chapter itself.
5843: Alternatively, the chapter title can be made to appear in place of the
5844: reference by writing this <tt>Copy</tt>rule:</p>
5845: <pre> Copy (ChapterTitle);</pre>
5846:
5847: <p>To define a header box, named <tt>RunningTitle</tt>, which contains the
5848: title of the current chapter, the box's contents are defined in this
5849: way:</p>
5850: <pre>BOXES
1.1 cvs 5851: RunningTitle :
1.18 cvs 5852: Copy (ChapterTitle);</pre>
5853: </blockquote>
5854: </div>
5855: </div>
1.37 cvs 5856: <hr />
1.18 cvs 5857: </div>
1.1 cvs 5858:
1.18 cvs 5859: <div class="chapter">
1.37 cvs 5860: <h1><a name="sect5" id="sect5">The T language</a></h1>
1.1 cvs 5861:
1.18 cvs 5862: <div class="section">
1.37 cvs 5863: <h2><a name="sectb51" id="sectb51">Document translation</a></h2>
1.1 cvs 5864:
1.30 cvs 5865: <p>Because of its document model, Thot can produce documents in a high-level
1.37 cvs 5866: abstract form. This form, called the <em>canonical form</em> is specific to
1.1 cvs 5867: Thot; it is well suited to the editor's manipulations, but it does not
1.37 cvs 5868: necessarily suit other operations which might be applied to documents.
5869: Because of this, the Thot editor offers the choice of saving documents in its
5870: own form (the canonical form) or a format defined by the user. In the latter
5871: case, the Thot document is transformed by the translation program. This
5872: facility can also be used to export documents from Thot to systems using
5873: other formalisms.</p>
1.1 cvs 5874:
1.18 cvs 5875: <div class="subsection">
1.37 cvs 5876: <h3><a name="sectc511" id="sectc511">Translation principles</a></h3>
1.1 cvs 5877:
1.30 cvs 5878: <p>Document translation allows the export of documents to other systems which
1.37 cvs 5879: do not accept Thot's canonical form. Translation can be used to export
1.30 cvs 5880: document to source-based formatters like T<sub><big>E</big></sub>X,
1.37 cvs 5881: L<sup>A</sup>T<sub><big>E</big></sub>X, and <tt>troff</tt>. It can also be
5882: used to translate documents into interchange formats like SGML or HTML. To
1.1 cvs 5883: allow the widest range of possible exports, Thot does not limit the choice of
5884: translations, but rather allows the user to define the formalisms into which
1.18 cvs 5885: documents can be translated.</p>
1.30 cvs 5886:
5887: <p>For each document or object class, a set of translation rules can be
5888: defined, specifying how the canonical form should be transformed into a given
1.37 cvs 5889: formalism. These translation rules are grouped into <em>translation
1.18 cvs 5890: schemas</em>, each schema containing the rules necessary to translate a
1.1 cvs 5891: generic logical structure (document or object structure) into a particular
1.37 cvs 5892: formalism. The same generic logical structure can have several different
1.1 cvs 5893: translation schemas, each defining translation rules for a different
1.18 cvs 5894: formalism.</p>
1.30 cvs 5895:
1.37 cvs 5896: <p>Like presentation schemas, translation schemas are generic. Thus, they
1.30 cvs 5897: apply to an entire object or document class and permit translation of all
5898: documents or objects of that class.</p>
1.18 cvs 5899: </div>
1.1 cvs 5900:
1.18 cvs 5901: <div class="subsection">
1.37 cvs 5902: <h3><a name="sectc512" id="sectc512">Translation procedure</a></h3>
1.1 cvs 5903:
1.30 cvs 5904: <p>The translator works on the specific logical structure of the document
1.37 cvs 5905: being translated. It traverses the primary tree of this logical structure in
1.1 cvs 5906: pre-order and, at each node encountered, it applies the corresponding
5907: translation rules defined in the translation schema. Translation can be
1.18 cvs 5908: associated:</p>
5909: <ul>
1.30 cvs 5910: <li>with element types defined in the structure schema,</li>
5911: <li>with global or local attributes defined in the structure schema,</li>
5912: <li>with specific presentation rules,</li>
1.37 cvs 5913: <li>with the content of the leaves of the structure (characters, symbols
1.30 cvs 5914: and graphical elements)</li>
1.18 cvs 5915: </ul>
1.30 cvs 5916:
5917: <p>Thus, for each node, the translator applies all rules associated with the
1.1 cvs 5918: element type, all rules associated with each attribute (local or global)
5919: carried by the element, and if the element is a leaf of the tree, it also
1.10 cvs 5920: applies translation rules for characters, symbols, or graphical elements,
1.18 cvs 5921: depending on the type of the leaf.</p>
1.30 cvs 5922:
5923: <p>Rules associated with the content of leaves are different from all other
1.1 cvs 5924: rules: they specify only how to translate character strings, symbols, and
1.37 cvs 5925: graphical elements. All other rules, whether associated with element types,
1.1 cvs 5926: with specific presentation rules or with attributes, are treated similarly.
1.18 cvs 5927: These rules primarily allow:</p>
5928: <ul>
1.30 cvs 5929: <li>generation of a text constant or variable before or after the contents
5930: of an element,</li>
5931: <li>modification of the order in which elements appear after
5932: translation,</li>
5933: <li>removal of an element in the translated document,</li>
5934: <li>and writing messages on the user's terminal during translation.</li>
1.18 cvs 5935: </ul>
5936: </div>
5937: </div>
1.1 cvs 5938:
1.18 cvs 5939: <div class="section">
1.37 cvs 5940: <h2><a name="sectb52" id="sectb52">Translation definition language</a></h2>
1.1 cvs 5941:
1.30 cvs 5942: <p>Translation schemas are written in a custom language, called T, which is
1.37 cvs 5943: described in the rest of this chapter. The grammar of T is specified using
1.18 cvs 5944: the same <a href="#sectc321">meta-language</a> as was used for the S and P
1.1 cvs 5945: languages and the translation schemas are written using the same conventions
1.37 cvs 5946: as the structure and presentation schemas. In particular, the keywords of the
1.1 cvs 5947: T language (the stings between apostrophes in the following syntax rules) can
5948: be written in any combination of upper-case and lower-case letters, but
5949: identifiers created by the programmer must always be written in the same
1.18 cvs 5950: way.</p>
1.1 cvs 5951:
1.18 cvs 5952: <div class="subsection">
1.37 cvs 5953: <h3><a name="sectc521" id="sectc521">Organization of a translation
5954: schema</a></h3>
1.1 cvs 5955:
1.30 cvs 5956: <p>A translation schema is begun by the <tt>TRANSLATION</tt> keyword and is
1.37 cvs 5957: terminated by the <tt>END</tt> keyword. The <tt>TRANSLATION</tt> keyword is
5958: followed by the name of the generic structure for which a translation is
5959: being defined and a semicolon. This name must be identical to the name which
1.18 cvs 5960: appears after the <tt>STRUCTURE</tt> keyword in the corresponding structure
5961: schema.</p>
1.30 cvs 5962:
5963: <p>After this declaration of the structure, the following material appears in
1.18 cvs 5964: order:</p>
5965: <ul>
1.30 cvs 5966: <li>the length of lines produced by the translation,</li>
5967: <li>the character delimiting the end of the line,</li>
5968: <li>the character string which the translator will insert if it must
5969: line-break the translated text,</li>
1.37 cvs 5970: <li>declarations of
1.30 cvs 5971: <ul>
5972: <li>buffers,</li>
5973: <li>counters,</li>
5974: <li>constants,</li>
5975: <li>variables,</li>
5976: </ul>
5977: </li>
5978: <li>translation rules associated with element types,</li>
5979: <li>translation rules associated with attributes,</li>
5980: <li>translation rules associated with specific presentation rules,</li>
5981: <li>translation rules associated with characters strings, symbols and
5982: graphical elements.</li>
1.18 cvs 5983: </ul>
1.30 cvs 5984:
1.37 cvs 5985: <p>Each of these sections is introduced by a keyword followed by a sequence
5986: of declarations. All of these sections are optional, expect for the
5987: translation rules associated with element types. Many <tt>TEXTTRANSLATE</tt>
5988: sections can appear, each defining the rules for translating character
5989: strings of a particular alphabet.</p>
1.18 cvs 5990: <pre> TransSchema ='TRANSLATION' ElemID ';'
1.1 cvs 5991: [ 'LINELENGTH' LineLength ';' ]
5992: [ 'LINEEND' CHARACTER ';' ]
5993: [ 'LINEENDINSERT' STRING ';' ]
5994: [ 'BUFFERS' BufferSeq ]
5995: [ 'COUNTERS' CounterSeq ]
5996: [ 'CONST' ConstSeq ]
5997: [ 'VAR' VariableSeq ]
5998: 'RULES' ElemSeq
5999: [ 'ATTRIBUTES' AttrSeq ]
6000: [ 'PRESENTATION' PresSeq ]
1.30 cvs 6001: < 'TEXTTRANSLATE' TextTransSeq >
1.1 cvs 6002: [ 'SYMBTRANSLATE' TransSeq ]
6003: [ 'GRAPHTRANSLATE' TransSeq ]
1.18 cvs 6004: 'END' .</pre>
6005: </div>
1.1 cvs 6006:
1.18 cvs 6007: <div class="subsection">
1.37 cvs 6008: <h3><a name="sectc522" id="sectc522">Line length</a></h3>
1.1 cvs 6009:
1.30 cvs 6010: <p>If a <tt>LINELENGTH</tt> instruction is present after the structure
1.37 cvs 6011: declaration, the translator divides the text it produces into lines, each
6012: line having a length less than or equal to the integer which follows the
6013: <tt>LINELENGTH</tt> keyword. This maximum line length is expressed as a
6014: number of characters. The end of the line is marked by the character defined
6015: by the <tt>LINEEND</tt> instruction. When the translator breaks the lines on
1.1 cvs 6016: a space character in generated text, this space will be replaced by the
1.18 cvs 6017: character string defined by the <tt>LINEENDINSERT</tt> instruction.</p>
1.30 cvs 6018:
6019: <p>If the <tt>LINEEND</tt> instruction is not defined then the linefeed
6020: character (octal code 12) is used as the default line end character. If the
1.18 cvs 6021: <tt>LINEENDINSERT</tt> instruction is not defined, the linefeed character is
1.37 cvs 6022: inserted at the end of the produced lines. If there is no <tt>LINELENGTH</tt>
6023: instruction, the translated text is not divided into lines. Otherwise, if the
1.1 cvs 6024: translation rules generate line end marks, these marks remain in the
6025: translated text, but the length of the lines is not controlled by the
1.18 cvs 6026: translator.</p>
6027: <pre> LineLength = NUMBER .</pre>
1.30 cvs 6028:
1.18 cvs 6029: <blockquote class="example">
1.30 cvs 6030: <p><strong>Example:</strong></p>
6031:
6032: <p>To limit the lines produced by the translator to a length of 80
6033: characters, the following rule is written at the beginning of the
6034: translation schema.</p>
6035: <pre>LineLength 80;</pre>
1.18 cvs 6036: </blockquote>
6037: </div>
1.1 cvs 6038:
1.18 cvs 6039: <div class="subsection">
1.37 cvs 6040: <h3><a name="sectc523" id="sectc523">Buffers</a></h3>
1.1 cvs 6041:
1.37 cvs 6042: <p>A buffer is a unit of memory managed by the translator, which can either
1.18 cvs 6043: contain text read from the terminal during the translation (see the <a
6044: href="#sectc5212"><tt>Read</tt> rule</a>), or the name of the last picture
1.1 cvs 6045: (bit-map) encountered by the translator in its traversal of the document.
1.2 cvs 6046: Remember the pictures are stored in files that are separate for the document
1.1 cvs 6047: files and that the canonical form contains only the names of the files in
1.18 cvs 6048: which the pictures are found.</p>
1.30 cvs 6049:
1.37 cvs 6050: <p>Thus, there are two types of buffers: buffers for reading from the
1.30 cvs 6051: terminal (filled by the <tt>Read</tt> rule) and the buffer of picture names
1.37 cvs 6052: (containing the name of the last picture encountered). A translation schema
1.30 cvs 6053: can use either type, one or several read buffers and one (and only one)
6054: picture name buffer.</p>
6055:
6056: <p>If any buffers are used, the <tt>BUFFERS</tt> keyword must be present,
1.37 cvs 6057: followed by declarations of every buffer used in the translation schema. Each
6058: buffer declaration is composed only of the name of the buffer, chosen freely
6059: by the programmer. The picture name buffer is identified by the
6060: <tt>Picture</tt> keyword, between parentheses, following the buffer name. The
6061: <tt>Picture</tt> keyword may only appear once. Each buffer declaration is
1.18 cvs 6062: terminated by a semicolon.</p>
1.30 cvs 6063: <pre> BufferSeq = Buffer < Buffer > .
1.1 cvs 6064: Buffer = BufferID [ '(' 'Picture' ')' ] ';' .
1.18 cvs 6065: BufferID = NAME .</pre>
1.30 cvs 6066:
1.18 cvs 6067: <blockquote class="example">
1.30 cvs 6068: <p><strong>Example:</strong></p>
6069:
6070: <p>The following buffer declarations create a picture name buffer named
1.37 cvs 6071: <tt>pictureName</tt> and a read buffer named <a name="destname"
6072: id="destname"><tt>DestName</tt></a>:</p>
1.30 cvs 6073: <pre>BUFFERS
1.18 cvs 6074: pictureName (Picture); DestName;</pre>
6075: </blockquote>
6076: </div>
1.1 cvs 6077:
1.18 cvs 6078: <div class="subsection">
1.37 cvs 6079: <h3><a name="sectc524" id="sectc524">Counters</a></h3>
1.30 cvs 6080:
6081: <p>Certain translation rules generate text that varies according to the
1.37 cvs 6082: context of the element to which the rules apply. Variable text is defined
1.30 cvs 6083: either in the <a href="#sectc526"><tt>VAR</tt> section</a> of the translation
6084: schema or in the rule itself (see the <tt>Create</tt> and <tt>Write</tt>
1.37 cvs 6085: rules). Both types of definition rely on counters for the calculation of
1.30 cvs 6086: variable material.</p>
6087:
6088: <p>There are two types of counter: counters whose value is explicitely
6089: computed by applying <a href="#sectc5221"><tt>Set</tt> and <tt>Add</tt>
6090: rules</a>, and counters whose value is computed by a function associated with
6091: the counter. Those functions allow the same calculations as can be used in
1.37 cvs 6092: presentation schemas. As in a presentation schema, counters must be defined
6093: in the <tt>COUNTERS</tt> section of the translation schema before they are
1.30 cvs 6094: used.</p>
6095:
6096: <p>When counters are used in a translation schema, the <tt>COUNTERS</tt>
1.37 cvs 6097: keyword is followed by the declarations of every counter used. Each
6098: declaration is composed of the counter's name possibly followed by a colon
6099: and the counting function to be used for the counter. The declaration is
1.30 cvs 6100: terminated by a semi-colon. If the counter is explicitely computed by
6101: <tt>Set</tt> and <tt>Add</tt> rules, no counting function is indicated. If a
6102: counting function is indicated, <tt>Set</tt> and <tt>Add</tt> rules cannot be
6103: applied to that counter.</p>
1.1 cvs 6104:
1.30 cvs 6105: <p>The counting function indicates how the counter's value will be computed.
1.18 cvs 6106: Three functions are available: <tt>Rank</tt>, <tt>Rlevel</tt>, and
6107: <tt>Set</tt>.</p>
6108: <ul>
1.30 cvs 6109: <li><tt>Rank of ElemID</tt> indicates that the counter's value is the rank
6110: of the element of type <tt>ElemID</tt> which encloses the element for
1.37 cvs 6111: which the counter is being evaluated. For the purposes of this function,
6112: an element of type <tt>ElemID</tt> is considered to enclose itself. This
6113: function is primarily used when the element of type <tt>ElemID</tt> is
1.30 cvs 6114: part of an aggregate or list, in which case the counter's value is the
1.37 cvs 6115: element's rank in its list or aggregate. Note that, unlike the
6116: <tt>Rank</tt> function for presentation schemas, the <tt>Page</tt>
6117: keyword cannot be used in place of the <tt>ElemID</tt>.
6118: <p>The type name <tt>ElemID</tt> can be followed by an integer. That
6119: number represents the relative level, among the ancestors of the
6120: concerned element, of the element whose rank is asked. If that relative
6121: level <i>n</i> is unsigned, the <i>n<sup>th</sup></i> element of type
6122: <tt>ElemID</tt> encountered when travelling the logical structure from
6123: the root to the concerned element is taken into account. If the relative
1.30 cvs 6124: level is negative, the logical structure is travelled in the other
6125: direction, from the concerned element to the root.</p>
6126: </li>
6127: <li><tt>Rlevel of ElemID</tt> indicates that the counter's values is the
6128: relative level in the tree of the element for which the counter is being
6129: evaluated. The counter counts the number of elements of type
6130: <tt>ElemID</tt> which are found on the path between the root of the
6131: document's logical structure tree and the element (inclusive).</li>
6132: <li><tt>Set n on Type1 Add m on Type2</tt> indicates that the counter's
1.37 cvs 6133: value is calculated as follows: in traversing the document from the
1.30 cvs 6134: beginning to the element for which the counter is being evaluated, the
6135: counter is set to the value <tt>n</tt> each time a <tt>Type1</tt> element
6136: is encountered and is incremented by the amount <tt>m</tt> each time a
1.37 cvs 6137: <tt>Type2</tt> element is encountered. The initial value <tt>n</tt> and
1.30 cvs 6138: the increment <tt>m</tt> are integers.</li>
6139: </ul>
6140:
6141: <p>As in a presentation schema, the <tt>Rank</tt> and <tt>Set</tt> functions
1.37 cvs 6142: can be modified by a numeric attribute which changes their initial value.
6143: This is indicated by the <tt>Init</tt> keyword followed by the numeric
6144: attribute's name. The <tt>Set</tt> function takes the value of the attribute
6145: instead of the <tt>InitValue</tt> (<tt>n</tt>). For the <tt>Rank</tt>
6146: function, the value of the attribute is considered to be the rank of the
6147: first element of the list (rather than the normal value of 1). Subsequent
6148: items in the list have their ranks shifted accordingly. In both cases, the
6149: attribute must be numeric and must be a local attribute of the root of the
6150: document itself.</p>
1.30 cvs 6151: <pre> CounterSeq = Counter < Counter > .
1.1 cvs 6152: Counter = CounterID [ ':' CounterFunc ] ';' .
6153: CounterID = NAME .
6154: CounterFunc = 'Rank' 'of' ElemID [ SLevelAsc ]
6155: [ 'Init' AttrID ] /
6156: 'Rlevel' 'of' ElemID /
6157: 'Set' InitValue 'On' ElemID
6158: 'Add' Increment 'On' ElemID
6159: [ 'Init' AttrID ] .
6160: SLevelAsc = [ '-' ] LevelAsc .
6161: LevelAsc = NUMBER .
6162: InitValue = NUMBER .
6163: Increment = NUMBER .
6164: ElemID = NAME .
1.18 cvs 6165: AttrID = NAME .</pre>
1.30 cvs 6166:
1.18 cvs 6167: <blockquote class="example">
1.30 cvs 6168: <p><strong>Example:</strong></p>
6169:
6170: <p>If the body of a chapter is defined in the structure schema by:</p>
6171: <pre>Chapter_Body = LIST OF
1.1 cvs 6172: (Section = BEGIN
6173: Section_Title = Text;
6174: Section_Body = BEGIN
6175: Paragraphs;
6176: Section;
6177: END;
6178: END
1.18 cvs 6179: );</pre>
1.30 cvs 6180:
6181: <p>(sections are defined recursively), a counter can be defined giving the
1.37 cvs 6182: <a name="sectnum" id="sectnum">number of a section</a> within its level in
6183: the hierarchy:</p>
1.30 cvs 6184: <pre>COUNTERS
1.18 cvs 6185: SectionNumber : Rank of Section;</pre>
1.30 cvs 6186:
6187: <p>A counter holding the hierarchic level of a section:</p>
6188: <pre> SectionLevel : Rlevel of Section;</pre>
6189:
1.37 cvs 6190: <p>A <a name="uniquenum" id="uniquenum">counter</a> which sequentially
6191: numbers all the document's sections, whatever their hierarchic level:</p>
1.30 cvs 6192: <pre> UniqueSectNum : Set 0 on Document Add 1 on Section;</pre>
1.18 cvs 6193: </blockquote>
6194: </div>
1.1 cvs 6195:
1.18 cvs 6196: <div class="subsection">
1.37 cvs 6197: <h3><a name="sectc525" id="sectc525">Constants</a></h3>
1.1 cvs 6198:
1.30 cvs 6199: <p>A common feature of translation rules is the generation of constant text.
1.37 cvs 6200: This text can be defined in the rule that generates it (see for example the
6201: <a href="#sectc5210"><tt>Create</tt></a> and <a
1.18 cvs 6202: href="#sectc5211"><tt>Write</tt></a> rules); but it can also be defined once
6203: in the constant declaration section and used many times in different rules.
1.37 cvs 6204: The latter option is preferable when the same text is used in several rules
6205: or several <a href="#sectc526">variables</a>.</p>
1.30 cvs 6206:
6207: <p>The <tt>CONST</tt> keyword begins the constant declaration section of the
1.37 cvs 6208: translation schema. It must be omitted if no constants are declared. Each
6209: constant declaration is composed of the constant name, an equals sign, and
6210: the constant's value, which is a character string between apostrophes. A
6211: constant declaration is terminated by a semicolon.</p>
1.30 cvs 6212: <pre> ConstSeq = Const < Const > .
1.1 cvs 6213: Const = ConstID '=' ConstValue ';' .
6214: ConstID = NAME .
1.18 cvs 6215: ConstValue = STRING .</pre>
1.30 cvs 6216:
1.18 cvs 6217: <blockquote class="example">
1.37 cvs 6218: <p><strong><a name="levelexample"
6219: id="levelexample">Example:</a></strong></p>
1.30 cvs 6220:
6221: <p>The following rule assigns the name <tt>TxtLevel</tt> to the character
6222: string ``Level'':</p>
6223: <pre>CONST
1.18 cvs 6224: TxtLevel = 'Level';</pre>
6225: </blockquote>
6226: </div>
1.1 cvs 6227:
1.18 cvs 6228: <div class="subsection">
1.37 cvs 6229: <h3><a name="sectc526" id="sectc526">Variables</a></h3>
1.1 cvs 6230:
1.30 cvs 6231: <p>Variables allow to define variable text which is generated by the
1.37 cvs 6232: <tt>Create</tt> and <tt>Write</tt> rules. They are also used to define file
1.18 cvs 6233: names which are used in the <tt>Create</tt>, <tt>ChangeMainFile</tt>,
1.37 cvs 6234: <tt>RemoveFile</tt>, and <tt>Indent</tt> rules. Variables can be defined
1.18 cvs 6235: either in the <tt>VAR</tt> section of the translation schema or directly in
1.37 cvs 6236: the rules which use them. Variables that define file names must be declared
1.18 cvs 6237: in the <tt>VAR</tt> section, and when the same variable is used several times
6238: in the translation schema, it makes sense to define it globally in the
1.37 cvs 6239: <tt>VAR</tt> section. This section is only present if at least one variable
1.18 cvs 6240: is defined globally.</p>
1.30 cvs 6241:
6242: <p>After the <tt>VAR</tt> keyword, each global variable is defined by its
6243: name, a colon separator and a sequence of functions (at least one function).
1.37 cvs 6244: Each variable definition is terminated by a semicolon. Functions determine
6245: the different parts which together give the value of the variable. The value
6246: is obtained by concatenating the strings produced by each of the functions.
6247: Seven types of functions are available. Each variable definition may use any
6248: number of functions of each type.</p>
1.18 cvs 6249: <ul>
1.30 cvs 6250: <li>The function <tt>Value(Counter)</tt>returns a string representing the
6251: value taken by the counter when it is evaluated for the element in whose
1.37 cvs 6252: rule the variable is used. The counter must have been declared in the
6253: <tt>COUNTERS</tt> section of the translation schema. When the counter is
1.30 cvs 6254: expressed in arabic numerals, the counter name can be followed by a colon
6255: and an integer indicating a minimum length (number of characters) for the
1.37 cvs 6256: string; if the counter's value is normally expressed with fewer
6257: characters than the required minimum, zeroes are added to the front of
6258: the string to achieve the minimum length.
1.30 cvs 6259: <p>By default, the counter value is written in arabic digits. If another
6260: representation of that value is needed, the counter name must be followed
6261: by a comma and one of the following keywords:</p>
6262: <ul>
6263: <li><tt>Arabic</tt>: arabic numerals (default value),</li>
6264: <li><tt>LRoman</tt>: lower-case roman numerals,</li>
6265: <li><tt>URoman</tt>: upper-case roman numerals,</li>
6266: <li><tt>Uppercase</tt>: upper-case letter,</li>
6267: <li><tt>Lowercase</tt>: lower-case letter.</li>
6268: </ul>
6269: </li>
6270: <li>The function <tt>FileDir</tt>, without parameter, returns a string
6271: representing the name of the directory of the output file that has been
6272: given as a parameter to the translation program. The string includes a
6273: character '/' at the end.</li>
6274: <li>The function <tt>FileName</tt>, without parameter, returns a string
6275: representing the name of the output file that has been given as a
6276: parameter to the translation program. The file extension (the character
6277: string that terminate the file name, after a dot) is not part of that
6278: string.</li>
6279: <li>The function <tt>Extension</tt>, without parameter, returns a string
6280: representing the extension of the file name. That string is empty if the
6281: file name that has been given as a parameter to the translation program
6282: has no extension. If there is an extension, its first character is a
6283: dot.</li>
6284: <li>The function <tt>DocumentName</tt>, without parameter, returns a string
6285: representing the name of the document being translated.</li>
6286: <li>The function <tt>DocumentDir</tt>, without parameter, returns a string
6287: representing the directory containing the document being translated.</li>
6288: <li>The function formed by the name of a constant returns that constant's
6289: value.</li>
6290: <li>The function formed by a character string between apostrophes returns
6291: that string.</li>
1.37 cvs 6292: <li>The function formed by the name of a buffer returns the contents of
6293: that buffer. If the named buffer is the picture buffer, then the name of
6294: the last picture encountered is returned. Otherwise, the buffer is a read
1.31 cvs 6295: buffer and the value returned is text previously read from the terminal.
1.30 cvs 6296: If the buffer is empty (no picture has been encountered or the
6297: <tt>Read</tt> rule has not been executed for the buffer), then the empty
6298: string is returned.</li>
6299: <li>The function formed by an attribute name takes the value of the
1.37 cvs 6300: indicated attribute for the element to which the variable applies. If the
1.30 cvs 6301: element does not have that attribute, then the element's ancestor are
1.37 cvs 6302: searched toward the root of the tree. If one of the ancestors does have
6303: the attribute then its value is used. If no ancestors have the attribute,
1.30 cvs 6304: then the value of the function is the empty string.</li>
1.18 cvs 6305: </ul>
1.30 cvs 6306: <pre> VariableSeq = Variable < Variable > .
6307: Variable = VarID ':' Function < Function > ';' .
1.1 cvs 6308: VarID = NAME .
6309: Function ='Value' '(' CounterID [ ':' Length ]
6310: [ ',' CounterStyle ] ')' /
6311: 'FileDir' / 'FileName' / 'Extension' /
6312: 'DocumentName' / 'DocumentDir' /
6313: ConstID / CharString /
6314: BufferID / AttrID .
6315: Length = NUMBER .
6316: CounterStyle= 'Arabic' / 'LRoman' / 'URoman' /
6317: 'Uppercase' / 'Lowercase' .
1.18 cvs 6318: CharString = STRING .</pre>
1.30 cvs 6319:
1.18 cvs 6320: <blockquote class="example">
1.30 cvs 6321: <p><strong>Example:</strong></p>
6322:
6323: <p>To create, at the beginning of each section of the translated document,
6324: text composed of the string ``Section'' followed by the section number, the
1.37 cvs 6325: following <a name="varsectexample" id="varsectexample">variable
6326: definition</a> might be used:</p>
1.30 cvs 6327: <pre>VAR
1.18 cvs 6328: SectionVar : 'Section' Value(SectionNumber);</pre>
1.30 cvs 6329:
6330: <p>(see the definition of <a
6331: href="#sectnum"><tt>SectionNumber</tt></a>).</p>
6332:
1.37 cvs 6333: <p>The following variable definition can be used to create, at the
6334: beginning of each section, the text ``Level'' followed by the hierarchical
6335: level of the section. It used the constant defined above.</p>
1.30 cvs 6336: <pre> LevelVar : TxtLevel Value(SectionLevel);</pre>
6337:
6338: <p>(see the definitions of <a href="#sectnum"><tt>SectionLevel</tt></a> and
6339: of <a href="#levelexample"><tt>TxtLevel</tt></a>).</p>
6340:
6341: <p>To generate the translation of each section in a different file (see <a
1.37 cvs 6342: href="#sectc5220">rule <tt>ChangeMainFile</tt></a>), the name of these
6343: files might be defined by the following variable:</p>
1.30 cvs 6344: <pre> VarOutpuFile : FileName Value(SectionNumber)
1.18 cvs 6345: Extension;</pre>
1.30 cvs 6346:
1.37 cvs 6347: <p>If <tt>output.txt</tt> is the name of the <a name="varoutputfile"
6348: id="varoutputfile">output file</a> specified when starting the translation
6349: program, translated sections are written in files <tt>output1.txt</tt>,
6350: <tt>output2.txt</tt>, etc.</p>
1.18 cvs 6351: </blockquote>
6352: </div>
6353:
6354: <div class="subsection">
1.37 cvs 6355: <h3><a name="sectc527" id="sectc527">Translating structure elements</a></h3>
1.18 cvs 6356:
1.30 cvs 6357: <p>The <tt>RULES</tt> keyword introduces the translation rules which will be
1.37 cvs 6358: applied to the various structured element types. Translation rules can be
6359: specified for each element type defined in the structure schema, including
6360: the base types defined implicitly, whose names are <tt>TEXT_UNIT</tt>,
1.18 cvs 6361: <tt>PICTURE_UNIT</tt>, <tt>SYMBOL_UNIT</tt>, <tt>GRAPHIC_UNIT</tt> and
1.37 cvs 6362: <tt>PAGE_UNIT</tt>. But it is not necessary to specify rules for every
1.18 cvs 6363: defined type.</p>
1.30 cvs 6364:
1.37 cvs 6365: <p>If there are no translation rules for an element type, the elements that
6366: it contains (and which may have rules themselves) will still be translated,
6367: but the translator will produce nothing for the element itself. To make the
1.18 cvs 6368: translator completely ignore the content of an element the <a
6369: href="#sectc5217"><tt>Remove</tt> rule</a> must be used.</p>
1.30 cvs 6370:
6371: <p>The translation rules for an element type defined in the structure schema
6372: are written using the name of the type followed by a colon and the list of
1.37 cvs 6373: applicable rules. When the element type is a <a href="#sectd3285">mark
1.18 cvs 6374: pair</a>, but only in this case, the type name must be preceded by the
1.37 cvs 6375: <tt>First</tt> or <tt>Second</tt> keyword. This keyword indicates whether the
1.18 cvs 6376: rules that follow apply to the first or second mark of the pair.</p>
1.30 cvs 6377:
1.37 cvs 6378: <p>The list of rules can take several forms. It may be a simple
6379: non-conditional rule. It can also be formed by a condition followed by one or
6380: more simple rules. Or it can be a block of rules beginning with the
1.30 cvs 6381: <tt>BEGIN</tt> keyword and ending with the <tt>END</tt> keyword and a
1.37 cvs 6382: semicolon. This block of rules can contain one or more simple rules and/or
1.30 cvs 6383: one or more conditions, each followed by one or more simple rules.</p>
6384: <pre> ElemSeq = TransType < TransType > .
1.1 cvs 6385: TransType = [ FirstSec ] ElemID ':' RuleSeq .
6386: FirstSec = 'First' / 'Second' .
1.30 cvs 6387: RuleSeq = Rule / 'BEGIN' < Rule > 'END' ';' .
1.1 cvs 6388: Rule = SimpleRule / ConditionBlock .
6389: ConditionBlock = 'IF' ConditionSeq SimpleRuleSeq .
1.30 cvs 6390: SimpleRuleSeq = 'BEGIN' < SimpleRule > 'END' ';' /
1.18 cvs 6391: SimpleRule .</pre>
6392: </div>
1.1 cvs 6393:
1.18 cvs 6394: <div class="subsection">
1.37 cvs 6395: <h3><a name="sectc528" id="sectc528">Conditional rules</a></h3>
1.1 cvs 6396:
1.30 cvs 6397: <p>In a translation schema, the translation rules are either associated with
1.37 cvs 6398: element types or with attribute values or with a specific presentation. They
1.1 cvs 6399: are applied by the translator each time an element of the corresponding type
6400: is encountered in the translated document or each time the attribute value is
6401: carried by an element or also, each time the specific translation is attached
1.37 cvs 6402: to an element. This systematic application of the rules can be relaxed: it is
6403: possible to add a condition to one or more rules, so that these rules are
6404: only applied when the condition is true.</p>
1.30 cvs 6405:
6406: <p>A condition begins with the keyword <tt>IF</tt>, followed by a sequence of
1.37 cvs 6407: elementary conditions. Elementary conditions are separated from each other by
6408: the <tt>AND</tt> keyword. If there is only one elementary condition, this
6409: keyword is absent. The rules are only applied if all the elementary
6410: conditions are true. The elementary condition can be negative; it is then
1.18 cvs 6411: preceded by the <tt>NOT</tt> keyword.</p>
1.30 cvs 6412:
6413: <p>When the translation rule(s) controlled by the condition apply to a
6414: reference element or a reference attribute, an elementary condition can also
1.37 cvs 6415: apply to element referred by this reference. The <tt>Target</tt> keyword is
6416: used for that purpose. It must appear before the keyword defining the
1.30 cvs 6417: condition type.</p>
6418:
6419: <p>Depending on their type, some conditions may apply either to the element
1.37 cvs 6420: with which they are associated, or to one of its ancestor. In the case of an
1.18 cvs 6421: ancestor, the key word <tt>Ancestor</tt> must be used, followed by</p>
6422: <ul>
1.30 cvs 6423: <li>either an integer which represents the number of levels in the tree
6424: between the element and the ancestor of interest,</li>
1.37 cvs 6425: <li>or the type name of the ancestor of interest. If that type is defined
1.30 cvs 6426: in a separate structure schema, the name of that schema must follow
6427: between parentheses.</li>
1.18 cvs 6428: </ul>
1.30 cvs 6429:
1.37 cvs 6430: <p>There is a special case for the parent element, which can be simply
6431: written <tt>Parent</tt> instead of <tt>Ancestor 1</tt>.</p>
1.30 cvs 6432:
6433: <p>Only conditions <tt>First</tt>, <tt>Last</tt>, <tt>Referred</tt>,
1.34 cvs 6434: <tt>Within</tt>, <tt>Attributes</tt>, <tt>Presentation</tt>, and those
6435: concerning an attribute or a specific presentation can apply to an ancestor.
6436: Conditions <tt>FirstRef</tt>, <tt>LastRef</tt>, <tt>ExternalRef</tt>,
6437: <tt>Alphabet</tt>, <tt>FirstAttr</tt>, <tt>LastAttr</tt>,
6438: <tt>ComputedPage</tt>, <tt>StartPage</tt>, <tt>UserPage</tt>,
6439: <tt>ReminderPage</tt>, <tt>Empty</tt> cannot be preceded by keywords
6440: <tt>Parent</tt> or <tt>Ancestor</tt>.</p>
1.30 cvs 6441:
1.37 cvs 6442: <p>In condition <tt>Referred</tt> and in the condition that applies to a
6443: named attribute, a symbol '<tt>*</tt>' can indicate that the condition is
6444: related only to the element itself. If this symbol is not present, not only
6445: the element is considered, but also its ancestor, at any level.</p>
1.30 cvs 6446:
6447: <p>The form of an elementary condition varies according to the type of
1.18 cvs 6448: condition.</p>
1.1 cvs 6449:
1.18 cvs 6450: <div class="subsubsection">
1.37 cvs 6451: <h4><a name="sectd5281" id="sectd5281">Conditions based on the logical
6452: position of the element</a></h4>
1.30 cvs 6453:
6454: <p>The condition can be on the position of the element in the document's
1.37 cvs 6455: logical structure tree. It is possible to test whether the element is the
1.30 cvs 6456: first (<tt>First</tt>) or last (<tt>Last</tt>) among its siblings or if it is
6457: not the first (<tt>NOT First</tt>) or not the last (<tt>NOT Last</tt>).</p>
6458:
6459: <p>It is also possible to test if the element is contained in an element of a
1.18 cvs 6460: given type (<tt>Within</tt>) or if it is not (<tt>NOT Within</tt>). If that
1.1 cvs 6461: element type is defined in a structure schema which is not the one which
6462: corresponds to the translation schema, the type name of this element must be
6463: followed, between parentheses, by the name of the structure schema which
1.18 cvs 6464: defines it.</p>
1.30 cvs 6465:
6466: <p>If the keyword <tt>Within</tt> is preceded by <tt>Immediately</tt>, the
1.18 cvs 6467: condition is satisfied only if the <em>parent</em> element has the type
6468: indicated. If the word <tt>Immediately</tt> is missing, the condition is
6469: satisfied if any <em>ancestor</em> has the type indicated.</p>
1.30 cvs 6470:
6471: <p>An integer <i>n</i> can appear between the keyword <tt>Within</tt> and the
1.37 cvs 6472: type. It specifies the number of ancestors of the indicated type that must be
6473: present for the condition to be satisfied. If the keyword
1.18 cvs 6474: <tt>Immediately</tt> is also present, the <i>n</i> immediate ancestors of the
1.37 cvs 6475: element must have the indicated type. The integer <i>n</i> must be positive
6476: or zero. It can be preceded by <tt><</tt> or <tt>></tt> to indicate a
6477: maximum or minimum number of ancestors. If these symbols are missing, the
6478: condition is satisfied only if it exists exactly <i>n</i> ancestors. When
1.30 cvs 6479: this number is missing, it is equivalent to > 0.</p>
6480:
1.37 cvs 6481: <p>If the condition applies to translation rules associated with an
6482: attribute, i.e. if it is in the <tt>ATTRIBUTES</tt> section of the
6483: presentation schema, the condition can be simply an element name. Translation
6484: rules are then executed only if the attribute is attached to an element of
6485: that type. The keyword <tt>NOT</tt> before the element name indicates that
6486: the translation rules must be executed only if the element is not of the type
6487: indicated.</p>
1.18 cvs 6488: </div>
1.1 cvs 6489:
1.18 cvs 6490: <div class="subsubsection">
1.37 cvs 6491: <h4><a name="sectd5282" id="sectd5282">Conditions on references</a></h4>
1.1 cvs 6492:
1.30 cvs 6493: <p>References may be taken into account in conditions, which can be based on
6494: the fact that the element, or one of its ancestors (unless symbol <tt>*</tt>
6495: is present), is designated by a at least one reference (<tt>Referred</tt>) or
1.37 cvs 6496: by none (<tt>NOT Referred</tt>). If the element or attribute to which the
1.1 cvs 6497: condition is attached is a reference, the condition can be based on the fact
6498: that it acts as the first reference to the designated element
1.18 cvs 6499: (<tt>FirstRef</tt>), or as the last (<tt>LastRef</tt>), or as a reference to
1.37 cvs 6500: an element located in another document (<tt>ExternalRef</tt>). Like all
1.18 cvs 6501: conditions, conditions on references can be inverted by the <tt>NOT</tt>
6502: keyword.</p>
6503: </div>
6504:
6505: <div class="subsubsection">
1.37 cvs 6506: <h4><a name="sectd5284" id="sectd5284">Conditions on the alphabets</a></h4>
1.1 cvs 6507:
1.30 cvs 6508: <p>The character string base type (and only this type) can use the condition
1.37 cvs 6509: <tt>Alphabet = a</tt> which indicates that the translation rule(s) should
6510: only apply if the alphabet of the character string is the one whose name
6511: appears after the equals sign (or is not, if there is a preceding
6512: <tt>NOT</tt> keyword). This condition cannot be applied to translation rules
6513: of an attribute.</p>
1.30 cvs 6514:
6515: <p>In the current implementation of Thot, the available alphabets are the
1.18 cvs 6516: <tt>Latin</tt> alphabet and the <tt>Greek</tt> alphabet.</p>
6517: </div>
1.1 cvs 6518:
1.18 cvs 6519: <div class="subsubsection">
1.37 cvs 6520: <h4><a name="sectd5285" id="sectd5285">Conditions on page breaks</a></h4>
1.1 cvs 6521:
1.30 cvs 6522: <p>The page break base type (and only this type) can use the following
1.18 cvs 6523: conditions: <tt>ComputedPage</tt>, <tt>StartPage</tt>, <tt>UserPage</tt>, and
1.37 cvs 6524: <tt>ReminderPage</tt>. The <tt>ComputedPage</tt> condition indicates that the
1.1 cvs 6525: translation rule(s) should apply if the page break was created automatically
1.37 cvs 6526: by Thot; the <tt>StartPage</tt> condition is true if the page break is
1.18 cvs 6527: generated before the element by the <tt>Page</tt> rule of the P language; the
6528: <tt>UserPage</tt> condition applies if the page break was inserted by the
1.37 cvs 6529: user; and the <tt>ReminderPage</tt> is applied if the page break is a
6530: reminder of page breaking.</p>
1.18 cvs 6531: </div>
1.1 cvs 6532:
1.18 cvs 6533: <div class="subsubsection">
1.37 cvs 6534: <h4><a name="sectd5286" id="sectd5286">Conditions on the element's
6535: content</a></h4>
1.1 cvs 6536:
1.37 cvs 6537: <p>The condition can be based on whether or not the element is empty. An
1.30 cvs 6538: element which has no children or whose leaves are all empty is considered to
1.37 cvs 6539: be empty itself. This condition is expressed by the <tt>Empty</tt> keyword,
1.30 cvs 6540: optionally preceded by the <tt>NOT</tt> keyword.</p>
1.18 cvs 6541: </div>
1.1 cvs 6542:
1.18 cvs 6543: <div class="subsubsection">
1.37 cvs 6544: <h4><a name="sectd5288" id="sectd5288">Conditions on the presence of specific
6545: presentation rules</a></h4>
1.30 cvs 6546:
6547: <p>The condition can be based on the presence or absence of specific
1.37 cvs 6548: presentation rules associated with the translated element, whatever the
6549: rules, their value or their number. This condition is expressed by the
6550: keyword <tt>Presentation</tt>, optionally preceded by the <tt>NOT</tt>
6551: keyword.</p>
1.18 cvs 6552: </div>
1.1 cvs 6553:
1.18 cvs 6554: <div class="subsubsection">
1.37 cvs 6555: <h4><a name="sectd5289" id="sectd5289">Conditions on the presence of logical
1.18 cvs 6556: attributes</a></h4>
1.30 cvs 6557:
6558: <p>In the same way, the condition can be based on the presence or absence of
1.1 cvs 6559: attributes associated with the translated elements, no matter what the
1.37 cvs 6560: attributes or their values. The <tt>Attributes</tt> keyword expresses this
1.18 cvs 6561: condition.</p>
6562: </div>
1.1 cvs 6563:
1.18 cvs 6564: <div class="subsubsection">
1.37 cvs 6565: <h4><a name="sectd52810" id="sectd52810">Conditions on logical
6566: attributes</a></h4>
1.1 cvs 6567:
1.30 cvs 6568: <p>If the condition appears in the translation rules of an attribute, the
1.37 cvs 6569: <tt>FirstAttr</tt> and <tt>LastAttr</tt> keywords can be used to indicate
6570: that the rules must only be applied if this attribute is the first attribute
6571: for the translated element or if it is the last (respectively). These
6572: conditions can also be inverted by the <tt>NOT</tt> keyword.</p>
6573:
6574: <p>Another type of condition can only be applied to the translation rules
6575: when the element being processed (or one of its ancestors if symbol
6576: <tt>*</tt> is missing) has a certain attribute, perhaps with a certain value
6577: or, in contrast, when the element does not have this attribute with this
6578: value. The condition is specified by writing the name of the attribute after
6579: the keyword <tt>IF</tt> or <tt>AND</tt>. The <tt>NOT</tt> keyword can be used
6580: to invert the condition. If the translation rules must be applied to any
6581: element which has this attribute (or does not have it, if the condition is
6582: inverted) no matter what the attribute's value, the condition is complete.
6583: If, in contrast, the condition applies to one or more values of the
6584: attribute, these are indicated after the name of the attribute, except for
6585: reference attributes which do not have values.</p>
6586:
6587: <p>The representation of the values of an <a name="relattr"
6588: id="relattr">attribute</a> in a condition depends on the attribute's type.
6589: For attributes with enumerated or textual types, the value (a name or
6590: character string between apostrophes, respectively) is simply preceded by an
6591: equals sign. For numeric attributes, the condition can be based on a single
6592: value or on a range of values. In the case of a unique value, this value (an
6593: integer) is simply preceded by an equals sign. Conditions based on ranges of
6594: values have several forms:</p>
1.18 cvs 6595: <ul>
1.30 cvs 6596: <li>all values less than a given value (the value is preceded by a ``less
6597: than'' sign).</li>
6598: <li>all values greater than a given value (the value is preceded by a
6599: ``greater than'' sign).</li>
1.37 cvs 6600: <li>all values falling in an interval, bounds included. The range of values
6601: is then specified <tt>IN [</tt>Minimum <tt>..</tt>Maximum<tt>]</tt>,
6602: where Minimum and Maximum are integers.</li>
1.18 cvs 6603: </ul>
1.30 cvs 6604:
1.37 cvs 6605: <p>All numeric values may be negative. The integer is simply preceded by a
1.30 cvs 6606: minus sign.</p>
6607:
6608: <p>Both local and global attributes can be used in conditions.</p>
1.18 cvs 6609: </div>
1.1 cvs 6610:
1.18 cvs 6611: <div class="subsubsection">
1.37 cvs 6612: <h4><a name="sectd52811" id="sectd52811">Conditions on specific presentation
6613: rules</a></h4>
1.1 cvs 6614:
1.30 cvs 6615: <p>It is possible to apply translation rules only when the element being
1.1 cvs 6616: processed has or does not have a specific presentation rule, possibly with a
1.37 cvs 6617: certain value. The condition is specified by writing the name of the
6618: presentation rule after the keyword <tt>IF</tt> or <tt>AND</tt>. The
6619: <tt>NOT</tt> keyword can be used to invert the condition. If the translation
6620: rules must be applied to any element which has this presentation rule (or
6621: does not have it, if the condition is inverted) no matter what the rule's
6622: value, the condition is complete. If, in contrast, the condition applies to
6623: one or more values of the rule, these are indicated after the name of the
1.18 cvs 6624: attribute.</p>
1.30 cvs 6625:
1.37 cvs 6626: <p>The representation of presentation rule values in a condition is similar
6627: to that for attribute values. The representation of these values depend on
6628: the type of the presentation rule. There are three categories of presentation
1.18 cvs 6629: rules:</p>
6630: <ul>
1.30 cvs 6631: <li>those taking numeric values (<tt>Size, Indent, LineSpacing,
6632: LineWeight</tt>),</li>
1.36 cvs 6633: <li>those with values taken from a predefined list (<tt>Adjust, Hyphenate,
6634: Style, Weight, Font, UnderLine, Thickness, LineStyle</tt>),</li>
1.30 cvs 6635: <li>those whose value is a name (<tt>FillPattern, Background,
6636: Foreground</tt>).</li>
1.18 cvs 6637: </ul>
1.30 cvs 6638:
6639: <p>For presentation rules which take numeric values, the condition can take a
1.37 cvs 6640: unique value or a range of values. In the case of a unique value, this value
1.1 cvs 6641: (an integer) is simply preceded by an equals sign. Conditions based on ranges
1.18 cvs 6642: of values have several forms:</p>
6643: <ul>
1.30 cvs 6644: <li>all values less than a given value (the value is preceded by a ``less
6645: than'' sign).</li>
6646: <li>all values greater than a given value (the value is preceded by a
6647: ``greater than'' sign).</li>
1.37 cvs 6648: <li>all values falling in an interval, bounds included. The range of values
6649: is then specified <tt>IN [</tt>Minimum <tt>..</tt>Maximum<tt>]</tt>,
6650: where Minimum and Maximum are integers.</li>
1.18 cvs 6651: </ul>
1.30 cvs 6652:
1.37 cvs 6653: <p>Values for the <tt>Indent</tt>rule may be negative. The integer is then
1.2 cvs 6654: simply preceded by a minus sign and represents how far the first line starts
1.18 cvs 6655: to the left of the other lines.</p>
1.30 cvs 6656:
6657: <p>For presentation rules whose values are taken from predefined lists, the
1.37 cvs 6658: value which satisfies the condition is indicated by an equals sign followed
6659: by the name of the value.</p>
1.30 cvs 6660:
1.37 cvs 6661: <p>For presentation rule whose values are names, the value which satisfies
6662: the condition is indicated by the equals sign followed by the value's name.
6663: The names of fill patterns (the <tt>FillPattern</tt> rule) and of colors (the
1.18 cvs 6664: <tt>Foreground</tt> and <tt>Background</tt> rules) known to Thot are the same
6665: as in the P language.</p>
1.30 cvs 6666:
6667: <p>The syntax of conditions based on the specific presentation is the same as
6668: the syntax used to express the <a href="#sectc5224">translation of specific
1.18 cvs 6669: presentation rules</a>.</p>
1.30 cvs 6670:
6671: <p>When a condition has only one rule, the condition is simply followed by
1.37 cvs 6672: that rule. If it has several rules, they are placed after the condition
1.30 cvs 6673: between the keywords <tt>BEGIN</tt> and <tt>END</tt>.</p>
1.18 cvs 6674: <pre> ConditionSeq = Condition [ 'AND' Condition ] .
1.1 cvs 6675: Condition = [ 'NOT' ] [ 'Target' ] Cond .
6676: Cond = CondElem / CondAscend .
6677: CondElem ='FirstRef' / 'LastRef' /
6678: 'ExternalRef' /
6679: 'Alphabet' '=' Alphabet /
6680: 'ComputedPage' / 'StartPage' /
6681: 'UserPage' / 'ReminderPage' /
6682: 'Empty' /
1.11 cvs 6683: ElemID /
1.1 cvs 6684: 'FirstAttr' / 'LastAttr' .
6685: CondAscend = [ Ascend ] CondOnAscend .
6686: Ascend = '*' / 'Parent' / 'Ancestor' LevelOrType .
6687: LevelOrType = CondRelLevel / ElemID [ ExtStruct ] .
6688: CondRelLevel = NUMBER .
6689: CondOnAscend ='First' / 'Last' /
6690: 'Referred' /
6691: [ 'Immediately' ] 'Within' [ NumParent ]
6692: ElemID [ ExtStruct ] /
6693: 'Attributes' /
6694: AttrID [ RelatAttr ] /
6695: 'Presentation' /
1.34 cvs 6696: PresRule .
1.1 cvs 6697: NumParent = [ GreaterLess ] NParent .
1.30 cvs 6698: GreaterLess = '>' / '<' .
1.1 cvs 6699: NParent = NUMBER.
6700: ExtStruct = '(' ElemID ')' .
6701: Alphabet = NAME .
6702: RelatAttr ='=' Value /
1.30 cvs 6703: '>' [ '-' ] Minimum /
1.1 cvs 6704: '<' [ '-' ] Maximum /
6705: 'IN' '[' [ '-' ] MinInterval '..'
6706: [ '-' ] MaxInterval ']' .
6707: Value = [ '-' ] IntegerVal / TextVal / AttrValue .
6708: Minimum = NUMBER .
6709: Maximum = NUMBER .
6710: MinInterval = NUMBER .
6711: MaxInterval = NUMBER .
6712: IntegerVal = NUMBER .
6713: TextVal = STRING .
1.18 cvs 6714: AttrValue = NAME .</pre>
1.30 cvs 6715:
1.18 cvs 6716: <blockquote class="example">
1.30 cvs 6717: <p><strong>Example:</strong></p>
6718:
6719: <p>Suppose that after each element of type Section_Title it is useful to
6720: produce the text <tt>\label{SectX}</tt> where <tt>X</tt> represents the
6721: section number, but only if the section is designated by one or more
1.37 cvs 6722: references in the document. The following conditional rule produces this
1.30 cvs 6723: effect:</p>
6724: <pre>RULES
1.1 cvs 6725: Section_Title :
6726: IF Referred
1.18 cvs 6727: Create ('\label{Sect' Value(UniqueSectNum) '}\12') After;</pre>
1.30 cvs 6728:
6729: <p>(the declaration of the <a href="#sectc5224"><tt>UniqueSectNum</tt>
1.37 cvs 6730: counter</a> is given above). The string <tt>\12</tt> represents a line
1.30 cvs 6731: break.</p>
1.18 cvs 6732: </blockquote>
1.30 cvs 6733:
1.18 cvs 6734: <blockquote class="example">
1.30 cvs 6735: <p><strong>Example:</strong></p>
6736:
1.37 cvs 6737: <p>Suppose that for elements of the Elmnt type it would be useful to
6738: produce a character indicating the value of the numeric attribute Level
6739: associated with the element: an ``A'' for all values of Level less than 3,
6740: a ``B'' for values between 3 and 10 and a ``C'' for values greater than 10.
6741: This can be achieved by writing the following rules for the Elmnt type:</p>
1.30 cvs 6742: <pre>RULES
1.1 cvs 6743: Elmnt :
6744: BEGIN
6745: IF Level < 3
6746: Create 'A';
6747: IF Level IN [3..10]
6748: Create 'B';
1.30 cvs 6749: IF Level > 10
1.1 cvs 6750: Create 'C';
1.18 cvs 6751: END;</pre>
6752: </blockquote>
6753: </div>
6754: </div>
1.1 cvs 6755:
1.18 cvs 6756: <div class="subsection">
1.37 cvs 6757: <h3><a name="sectc529" id="sectc529">Translation rules</a></h3>
1.1 cvs 6758:
1.37 cvs 6759: <p>Fifteen types of translation rules can be associated with element types
6760: and attribute values. They are the <tt>Create</tt>, <tt>Write</tt>,
1.18 cvs 6761: <tt>Read</tt>, <tt>Include</tt>, <tt>Get</tt>, <tt>Copy</tt>, <tt>Use</tt>,
1.31 cvs 6762: <tt>Remove</tt>, <tt>Ignore</tt>, <tt>NoTranslation</tt>,
6763: <tt>NoLineBreak</tt>, <tt>ChangeMainFile</tt>, <tt>RemoveFile</tt>,
1.37 cvs 6764: <tt>Set</tt>, <tt>Add</tt>, <tt>Indent</tt>, rules. Each rule has its own
1.31 cvs 6765: syntax, although they are all based on very similar models.</p>
1.18 cvs 6766: <pre> SimpleRule = 'Create' [ 'IN' VarID ] Object
1.1 cvs 6767: [ Position ] ';' /
6768: 'Write' Object [ Position ] ';' /
6769: 'Read' BufferID [ Position ] ';' /
6770: 'Include' File [ Position ] ';' /
6771: 'Get' [ RelPosition ] ElemID
6772: [ ExtStruct ]
6773: [ Position ] ';' /
6774: 'Copy' [ RelPosition ] ElemID
6775: [ ExtStruct ]
6776: [ Position ] ';' /
6777: 'Use' TrSchema [ 'For' ElemID ] ';' /
6778: 'Remove' ';' /
1.31 cvs 6779: 'Ignore' ';' /
1.1 cvs 6780: 'NoTranslation' ';' /
6781: 'NoLineBreak' ';' /
6782: 'ChangeMainFile' VarID [ Position ] ';' /
1.14 cvs 6783: 'RemoveFile' VarID [ Position ] ';' /
1.10 cvs 6784: 'Set' CounterID InitValue [ Position ] ';' /
6785: 'Add' CounterID Increment [ Position ] ';' /
1.25 cvs 6786: 'Indent' [ 'IN' VarID ] Indent [ Position ] ';' .</pre>
1.18 cvs 6787: </div>
6788:
6789: <div class="subsection">
1.37 cvs 6790: <h3><a name="sectc5210" id="sectc5210">The <tt>Create</tt> rule</a></h3>
1.18 cvs 6791:
1.30 cvs 6792: <p>The most frequently used rule is undoubtedly the <tt>Create</tt> rule,
6793: which generates fixed or variable text (called an <em>object</em>) in the
1.37 cvs 6794: output file. The generated text can be made to appear either before or after
6795: the content of the element to which the rule applies. The rule begins with
6796: the <tt>Create</tt> keyword, followed by a specifier for the object and a
6797: keyword (<tt>Before</tt> or <tt>After</tt>) indicating the position of the
6798: generated text (<a href="#sectc5222">before or after</a> the element's
6799: content). If the position is not indicated, the object will be generated
6800: before the element's content. This rule, like all translation rules, is
6801: terminated by a semicolon.</p>
1.30 cvs 6802:
6803: <p>The <tt>Create</tt> keyword can be followed by the <tt>IN</tt> keyword and
1.37 cvs 6804: by the name of a variable. This means that the text generated by the rule
1.30 cvs 6805: must not be written in the main output file, but in the file whose name is
1.18 cvs 6806: specified by the variable.</p>
1.30 cvs 6807:
6808: <p>This allows the translation program to generate text in different files
6809: during the same run. These files do not need to be explicitely declared or
6810: opened. They do not need to be closed either, but if they contain temporary
6811: data, they can be removed (see the <a href="#sectc5220a"><tt>RemoveFile</tt>
6812: rule</a>). As soon as the translation program executes a <tt>Create</tt> rule
6813: for a file that is not yet open, it opens the file. These files are closed
6814: when the translation is finished.</p>
1.18 cvs 6815: <pre> 'Create' [ 'IN' VarID ] Object
1.1 cvs 6816: [ Position ] ';'
6817: Object = ConstID / CharString /
6818: BufferID /
6819: VarID /
1.30 cvs 6820: '(' Function < Function > ')' /
1.21 cvs 6821: [ 'Translated' ] AttrID /
1.1 cvs 6822: 'Value' /
6823: 'Content' /
6824: 'Attributes' /
6825: 'Presentation' /
6826: 'RefId' /
6827: 'PairId' /
6828: 'FileDir' /
6829: 'FileName' /
6830: 'Extension' /
6831: 'DocumentName' /
6832: 'DocumentDir' /
6833: [ 'Referred' ] ReferredObject .
6834: Position ='After' / 'Before' .
6835:
6836: ReferredObject = VarID /
6837: ElemID [ ExtStruct ] /
6838: 'RefId' /
6839: 'DocumentName' /
1.18 cvs 6840: 'DocumentDir' .</pre>
1.30 cvs 6841:
6842: <p>The object to be generated can be:</p>
1.18 cvs 6843: <ul>
1.30 cvs 6844: <li>a constant string, specified by its name if it is declared in the
6845: schema's <tt>CONST</tt> section, or given directly as a value between
6846: apostrophes;</li>
6847: <li>the contents of a buffer, designated by the name of the buffer;</li>
6848: <li>a variable, designated by its name if it is declared in the translation
1.37 cvs 6849: schema's <tt>VAR</tt> section, or given directly between parentheses. The
1.30 cvs 6850: text generated is the value of that variable evaluated for the element to
6851: which the rule applies.</li>
6852: <li>the value of an attribute, if the element being translated has this
6853: attribute. The attribute is specified by its name. If it's a text
6854: attribute, it can be preceded by the <code>Translated</code> keyword,
6855: which causes the attribute value to be recoded using the text translation
6856: table defined by section <code><a
6857: href="#sectc5225">TEXTTRANSLATE</a></code>;</li>
1.37 cvs 6858: <li>the value of a specific presentation rule. This object can only be
1.30 cvs 6859: generated if the translation rule is for a <a href="#prestransl">specific
1.37 cvs 6860: presentation rule</a>. It is specified by the <tt>Value</tt> keyword;</li>
6861: <li>the element's content. That is, the content of the leaves of the
6862: subtree of the translated element. This is specified by the
1.30 cvs 6863: <tt>Content</tt> keyword;</li>
6864: <li>the translation of all attributes of the element (which is primarily
6865: used to apply the attribute translation rules <a
1.37 cvs 6866: href="#sectc5222">before</a> those of the element type). This is
1.30 cvs 6867: specified by the <tt>Attributes</tt> keyword.</li>
6868: <li>the translation of all of the element's specific presentation rules
6869: (which is primarily used to apply the translation rules for the specific
1.37 cvs 6870: presentation rules <a href="#sectc5222">before</a> those of the element
6871: or its attributes). This option is specified by the <tt>Presentation</tt>
1.30 cvs 6872: keyword;</li>
1.37 cvs 6873: <li>The value of the reference's identifier.<br />
6874: Thot associates a unique identifier with each element in a document. This
6875: identifier (called <em>reference's identifier</em> or <em>label</em>) is
6876: a character string containing the letter `L' followed by digits. Thot
6877: uses it in references for identifying the referred element.<br />
1.30 cvs 6878: The <tt>RefId</tt> keyword produces the reference's identifier of the
6879: element to which the translation rule is applied, or the reference's
6880: identifier of its first ancestor that is referred by a reference or that
6881: can be referred by a reference.</li>
1.37 cvs 6882: <li>the value of a mark pair's unique identifier. This may only be used for
1.30 cvs 6883: <a href="#sectd3285">mark pairs</a> and is indicated by the
6884: <tt>PairId</tt> keyword.</li>
6885: <li>the directory containing the file being generated (this string includes
1.37 cvs 6886: an ending '/', if it is not empty). This is indicated by the
1.30 cvs 6887: <tt>FileDir</tt> keyword.</li>
6888: <li>the name of the file being generated (only the name, without the
6889: directory and without the extension). This is indicated by the
6890: <tt>FileName</tt> keyword.</li>
6891: <li>the extension of the file being generated (this string starts with a
1.37 cvs 6892: dot, if it is not empty). This is indicated by the <tt>Extension</tt>
1.30 cvs 6893: keyword.</li>
1.37 cvs 6894: <li>the name of the document being translated. This is indicated by the
1.30 cvs 6895: <tt>DocumentName</tt> keyword.</li>
1.37 cvs 6896: <li>the directory containing the document being translated. This is
1.30 cvs 6897: indicated by the <tt>DocumentDir</tt> keyword.</li>
1.18 cvs 6898: </ul>
1.30 cvs 6899:
1.37 cvs 6900: <p>When the rule applies to a reference (an element or an attribute defined
6901: as a reference in the structure schema), it can generate a text related to
6902: the element referred by that reference. The rule name is then followed by the
1.18 cvs 6903: <tt>Referred</tt> keyword and a specification of the object to be generated
1.37 cvs 6904: for the referred element. This specification can be:</p>
1.18 cvs 6905: <ul>
1.37 cvs 6906: <li>the name of a variable. The rule generates the value of that variable,
1.30 cvs 6907: computed for the referred element.</li>
1.37 cvs 6908: <li>an element type. The rule generates the translation of the element of
6909: that type, which is in the subtree of the referred element. If this
1.30 cvs 6910: element is not defined in the structure schema which corresponds to the
6911: translation schema (that is, an object defined in another schema), the
6912: element's type name must be followed by the name of its structure schema
6913: between parentheses.</li>
1.37 cvs 6914: <li>the <tt>RefId</tt> keyword. The rule generates the reference's
1.30 cvs 6915: identifier of the referred element.</li>
1.37 cvs 6916: <li>the <tt>DocumentName</tt> keyword. The rule generates the name of the
1.30 cvs 6917: document to which the referred element belongs.</li>
1.37 cvs 6918: <li>the <tt>DocumentDir</tt> keyword. The rule generates the name of the
1.30 cvs 6919: directory that contains the document of the referred element.</li>
1.18 cvs 6920: </ul>
6921: </div>
1.1 cvs 6922:
1.18 cvs 6923: <div class="subsection">
1.37 cvs 6924: <h3><a name="sectc5211" id="sectc5211">The <tt>Write</tt> rule</a></h3>
1.1 cvs 6925:
1.37 cvs 6926: <p>The <tt>Write</tt> has the same syntax as the <tt>Create</tt> rule. It
1.30 cvs 6927: also produces the same effect, but the generated text is displayed on the
6928: user's terminal during the translation of the document, instead of being
1.37 cvs 6929: produced in the translated document. This is useful for helping the user keep
1.30 cvs 6930: track of the progress of the translation and for prompting the user on the
6931: terminal for input required by the <tt>Read</tt> rule.</p>
1.18 cvs 6932: <pre> 'Write' Object [ Position ] ';'</pre>
1.30 cvs 6933:
6934: <p>Notice: if the translator is launched by the editor (by the ``Save as''
1.18 cvs 6935: command), messages produced by the <tt>Write</tt> rule are not displayed.</p>
1.30 cvs 6936:
1.18 cvs 6937: <blockquote class="example">
1.30 cvs 6938: <p><strong>Example:</strong></p>
6939:
6940: <p>To make the translator display the number of each section being
6941: translated on the user's terminal, the following rule is specified for the
6942: <tt>Section</tt> element type:</p>
6943: <pre>Section : BEGIN
1.1 cvs 6944: Write VarSection;
6945: ...
1.18 cvs 6946: END;</pre>
1.30 cvs 6947:
6948: <p>(see <a href="#varsectexample">above</a> for the definition of the
6949: <tt>VarSection</tt> variable).</p>
6950:
6951: <p>To display text on the terminal before issuing a read operation with the
6952: <tt>Read</tt> rule, the following rule is used:</p>
6953: <pre>BEGIN
1.1 cvs 6954: Write 'Enter the name of the destination: ';
6955: ...
1.18 cvs 6956: END;</pre>
6957: </blockquote>
6958: </div>
6959:
6960: <div class="subsection">
1.37 cvs 6961: <h3><a name="sectc5212" id="sectc5212">The <tt>Read</tt> rule</a></h3>
1.18 cvs 6962:
1.30 cvs 6963: <p>The <tt>Read</tt> rule reads text from the terminal during the translation
6964: of the document and saves the text read in one of the buffers declared in the
1.37 cvs 6965: <tt>BUFFERS</tt> section of the schema. The buffer to be used is indicated by
6966: its name, after the <tt>READ</tt> keyword. This name can be followed, as in
1.18 cvs 6967: the <tt>Create</tt> and <tt>Write</tt> rules, by a keyword indicating if the
6968: read operation must be performed <tt>Before</tt> or <tt>After</tt> the
1.37 cvs 6969: translation of the element's content. If this keyword is absent, the read
6970: operation is done beforehand. The text is read into the buffer and remains
1.5 cvs 6971: there until a rule using the same buffer - possibly the same rule - is
1.18 cvs 6972: applied.</p>
6973: <pre> 'Read' BufferID [ Position ] ';'</pre>
1.30 cvs 6974:
1.18 cvs 6975: <blockquote class="example">
1.30 cvs 6976: <p><strong>Example:</strong></p>
6977:
6978: <p>The following set of rules tells the user that the translator is waiting
6979: for the entry of some text, reads this text into a buffer and copies the
6980: text into the translated document.</p>
6981: <pre>BEGIN
1.1 cvs 6982: Write 'Enter the name of the destination: ';
6983: Read DestName;
6984: Create DestName;
6985: ...
1.18 cvs 6986: END;</pre>
1.30 cvs 6987:
6988: <p>(see <a href="#destname">above</a> the definition of
6989: <tt>DestName</tt>).</p>
1.18 cvs 6990: </blockquote>
6991: </div>
6992:
6993: <div class="subsection">
1.37 cvs 6994: <h3><a name="sectc5213" id="sectc5213">The <tt>Include</tt> rule</a></h3>
1.18 cvs 6995:
1.30 cvs 6996: <p>The <tt>Include</tt> rule, like the <tt>Create</tt> rule, is used to
1.37 cvs 6997: produce text in the translated document. It inserts constant text which is
6998: not defined in the translation schema, but is instead taken from a file. The
6999: file's name is specified after the <tt>Include</tt> keyword, either directly
7000: as a character string between apostrophes or as the name of one of the
7001: buffers declared in the <tt>BUFFERS</tt> section of the schema. In the latter
7002: case, the buffer is assumed to contain the file's name. This can be used when
7003: the included file's name is known only at the moment of translation. This
7004: only requires that the <tt>Include</tt> rule is preceded by a <tt>Read</tt>
7005: rule which puts the name of the file desired by the user into the buffer.</p>
1.30 cvs 7006:
7007: <p>Like the other rules, it is possible to specify whether the inclusion will
1.1 cvs 7008: occur before or after the element's content, with the default being before.
7009: The file inclusion is only done at the moment of translation, not during the
7010: compilation of the translation schema. Thus, the file to be included need not
7011: exist during the compilation, but it must be accessible at the time of
1.37 cvs 7012: translation. Its contents can also be modified between two translations, thus
1.1 cvs 7013: producing different results, even if neither the document or the translation
1.18 cvs 7014: schema are modified.</p>
1.30 cvs 7015:
7016: <p>During translation, the file to be included is searched for along the
7017: schema directory path (indicated by the environment variable
1.37 cvs 7018: <tt>THOTSCH</tt>). The file name is normally only composed of a simple name,
7019: without specification of a complete file path. However, if the filename
1.30 cvs 7020: starts with a '/', it is considered as an absolute path.</p>
1.18 cvs 7021: <pre> 'Include' File [ Position ] ';'
1.6 cvs 7022: File = FileName / BufferID .
1.18 cvs 7023: FileName = STRING .</pre>
1.30 cvs 7024:
1.18 cvs 7025: <blockquote class="example">
1.30 cvs 7026: <p><strong>Example:</strong></p>
7027:
1.37 cvs 7028: <p>Suppose that it is desirable to print documents of the Article class
7029: with a formatter which requires a number of declarations and definitions at
7030: the beginning of the file. The <tt>Include</tt>rule can be used to achieve
1.30 cvs 7031: this. All the declarations and definitions a replaced in a file called
7032: <tt>DeclarArt</tt> and then the <tt>Article</tt> element type is given the
7033: following rule:</p>
7034: <pre>Article : BEGIN
1.1 cvs 7035: Include 'DeclarArt' Before;
7036: ...
1.18 cvs 7037: END;</pre>
7038: </blockquote>
7039: </div>
7040:
7041: <div class="subsection">
1.37 cvs 7042: <h3><a name="sectc5214" id="sectc5214">The <tt>Get</tt> rule</a></h3>
1.18 cvs 7043:
1.30 cvs 7044: <p>The <tt>Get</tt> rule is used to change the order in which the elements
1.37 cvs 7045: appear in the translated document. More precisely, it produces the
1.30 cvs 7046: translation of a specified element before or after the translation of the
1.37 cvs 7047: content of the element to which the rule applies. The <tt>Before</tt> and
1.30 cvs 7048: <tt>After</tt> keywords are placed at the end of the rule to specify whether
7049: the operation should be performed before or after translation of the rule's
7050: element (the default is before). The type of the element to be moved must be
7051: specified after the <tt>Get</tt> keyword, optionally preceded by a keyword
7052: indicating where the element will be found in the logical structure of the
7053: document:</p>
1.18 cvs 7054: <dl>
1.30 cvs 7055: <dt><tt>Included</tt></dt>
7056: <dd>The element to be moved is the first element of the indicated type
7057: which is found inside the element to which the rule applies.</dd>
7058: <dt><tt>Referred</tt></dt>
7059: <dd>This keyword can only be used if the rule applies to a reference
1.37 cvs 7060: element. The element to be moved is either the element designated by
7061: the reference (if that element is of the specified type), or the first
1.30 cvs 7062: element of the desired type contained within the element designated by
7063: the reference.</dd>
7064: <dt>no keyword</dt>
1.37 cvs 7065: <dd><p>The translator takes the first element of the indicated type from
7066: among the siblings of the rule's element. This is primarily used to
7067: change the order of the components of an aggregate.</p>
1.30 cvs 7068: </dd>
1.18 cvs 7069: </dl>
1.30 cvs 7070:
7071: <p>If the element to be moved is defined in a structure schema which is not
7072: the one which corresponds to the translation schema (in the case of an
7073: included object with a different schema), the type name of this element must
7074: be followed, between parentheses, by the name of the structure schema which
1.18 cvs 7075: defines it.</p>
7076: <pre> 'Get' [ RelPosition ] ElemID
1.6 cvs 7077: [ ExtStruct ]
7078: [ Position ] ';' /
7079: RelPosition = 'Included' / 'Referred' .
1.18 cvs 7080: ExtStruct = '(' ElemID ')' .</pre>
1.30 cvs 7081:
7082: <p>The <tt>Get</tt> rule has no effect if the element which it is supposed to
1.37 cvs 7083: move has already been translated. Thus, the element will not be duplicated.
1.1 cvs 7084: It is generally best to associate the rule with the first element which will
1.37 cvs 7085: be encountered by the translator in its traversal of the document. Suppose an
1.18 cvs 7086: aggregate has two elements <tt>A</tt> and <tt>B</tt>, with <tt>A</tt>
1.37 cvs 7087: appearing first in the logical structure. To permute these two elements, a
1.18 cvs 7088: <tt>Get B before</tt> rule should be associated with the <tt>A</tt> element
1.37 cvs 7089: type, not the inverse. Similarly, a rule of the form <tt>Get Included X
1.18 cvs 7090: After</tt>, even though syntactically correct, makes no sense since, by the
1.1 cvs 7091: time it will be applied, after the translation of the contents of the element
1.18 cvs 7092: to which it is attached, the <tt>X</tt> element will already have been
7093: translated.</p>
7094: </div>
7095:
7096: <div class="subsection">
1.37 cvs 7097: <h3><a name="sectc5215" id="sectc5215">The <tt>Copy</tt> rule</a></h3>
1.18 cvs 7098:
1.30 cvs 7099: <p>Like the <tt>Get</tt> rule, the <tt>Copy</tt> rule generates the
7100: translation of a specified element, but it acts even if the element has
7101: already been translated and it allows to copy it or to translate it later.
7102: Both rules have the same syntax.</p>
1.18 cvs 7103: <pre> 'Copy' [ RelPosition ] ElemID
7104: [ ExtStruct ] [ Position ] ';'</pre>
7105: </div>
7106:
7107: <div class="subsection">
1.37 cvs 7108: <h3><a name="sectc5216" id="sectc5216">The <tt>Use</tt> rule</a></h3>
1.18 cvs 7109:
1.30 cvs 7110: <p>The <tt>Use</tt> rule specifies the translation schema to be applied to
1.37 cvs 7111: objects of a certain class that are part of the document. This rule only
1.1 cvs 7112: appears in the rules for the root element of the document (the first type
1.18 cvs 7113: defined after the <tt>STRUCT</tt> keyword in the structure schema) or the
1.1 cvs 7114: rules of an element defined by an external structure (by another structure
1.37 cvs 7115: schema). Also, the <tt>Use</tt> rule cannot be conditional.</p>
1.30 cvs 7116:
7117: <p>If the rule is applied to an element defined by an external structure, the
1.18 cvs 7118: <tt>Use</tt> keyword is simply followed by the name of the translation schema
1.37 cvs 7119: to be used for element constructed according to that external structure. If
1.1 cvs 7120: the rule is applied to the document's root element, it is formed by the
1.18 cvs 7121: <tt>Use</tt> keyword followed by the translation schema's name, the
7122: <tt>For</tt> keyword and the name of the external structure to which the
7123: indicated translation schema should be applied.</p>
7124: <pre> 'Use' TrSchema [ 'For' ElemID ] ';'
7125: TrSchema = NAME .</pre>
1.30 cvs 7126:
7127: <p>If no <tt>Use</tt> rule defines the translation schema to be used for an
1.1 cvs 7128: external structure which appears in a document, the translator asks the user,
7129: during the translation process, which schema should be used. Thus, it is not
1.18 cvs 7130: necessary to give the translation schema a <tt>Use</tt> rule for every
1.1 cvs 7131: external structure used, especially when the choice of translation schemas is
1.18 cvs 7132: to be left to the user.</p>
1.30 cvs 7133:
7134: <p>Notice: if the translator is launched by the editor (by the ``Save as''
1.18 cvs 7135: command), prompts are not displayed.</p>
1.30 cvs 7136:
1.18 cvs 7137: <blockquote class="example">
1.30 cvs 7138: <p><strong>Example:</strong></p>
7139:
7140: <p>The <tt>Article</tt> structure schema uses the <tt>Formula</tt> external
7141: structure, defined by another structure schema, for mathematical
7142: formulas:</p>
7143: <pre>STRUCTURE Article;
1.1 cvs 7144: ...
7145: STRUCT
7146: Article = ...
7147: ...
7148: Formula_in_text = Formula;
7149: Isolated_formula = Formula;
7150: ...
1.18 cvs 7151: END</pre>
1.30 cvs 7152:
7153: <p>Suppose that it would be useful to use the <tt>FormulaT</tt> translation
1.37 cvs 7154: schema for the formulas of an article. This can be expressed in two
1.30 cvs 7155: different ways in the <tt>Article</tt> class translation schema, using the
7156: rules:</p>
7157: <pre>RULES
1.1 cvs 7158: Article :
1.18 cvs 7159: Use FormulaT for Formula;</pre>
1.30 cvs 7160:
7161: <p>or:</p>
7162: <pre>RULES
1.1 cvs 7163: ...
7164: Formula :
1.18 cvs 7165: Use FormulaT;</pre>
7166: </blockquote>
7167: </div>
7168:
7169: <div class="subsection">
1.37 cvs 7170: <h3><a name="sectc5217" id="sectc5217">The <tt>Remove</tt> rule</a></h3>
1.18 cvs 7171:
1.37 cvs 7172: <p>The <tt>Remove</tt> rule indicates that nothing should be generated, in
7173: the translated document, for the content of the element to which the rule
7174: applies. The content of that element is simply ignored by the translator.
7175: This does not prevent the generation of text for the element itself, using
7176: the <tt>Create</tt> or <tt>Include</tt> rules, for example.</p>
1.30 cvs 7177:
7178: <p>The <tt>Remove</tt> rule is simply written with the <tt>Remove</tt>
7179: keyword. It is terminated, like all rules, by a semicolon.</p>
1.18 cvs 7180: <pre> 'Remove' ';'</pre>
7181: </div>
7182:
7183: <div class="subsection">
1.37 cvs 7184: <h3><a name="sectc5217a" id="sectc5217a">The <tt>Ignore</tt> rule</a></h3>
1.31 cvs 7185:
1.37 cvs 7186: <p>The <tt>Ignore</tt> rule indicates that nothing should be generated, in
7187: the translated document, for the element to which the rule applies. The whole
1.32 cvs 7188: element is simply ignored by the translator.</p>
1.31 cvs 7189:
7190: <p>The <tt>Ignore</tt> rule is simply written with the <tt>Ignore</tt>
7191: keyword. It is terminated, like all rules, by a semicolon.</p>
7192: <pre> 'Ignore' ';'</pre>
7193: </div>
7194:
7195: <div class="subsection">
1.37 cvs 7196: <h3><a name="sectc5218" id="sectc5218">The <tt>NoTranslation</tt>
7197: rule</a></h3>
1.18 cvs 7198:
1.30 cvs 7199: <p>The <tt>NoTranslation</tt> rule indicates to the translator that it must
1.37 cvs 7200: not translate the content of the leaves of the element to which it applies.
7201: In contrast to the <tt>Remove</tt> rule, it does not suppress the content of
7202: the element, but it inhibits the translation of character strings, symbols,
7203: and graphical elements contained in the element. These are retrieved so that
1.18 cvs 7204: after the translation of the document, the rules of the <a
7205: href="#sectc5225"><tt>TEXTTRANSLATE</tt>, <tt>SYMBTRANSLATE</tt> and
7206: <tt>GRAPHTRANSLATE</tt> sections</a> will not be applied to them.</p>
1.30 cvs 7207:
7208: <p>The <tt>NoTranslation</tt> rule is written with the <tt>NoTranslation</tt>
1.18 cvs 7209: keyword followed by a semicolon.</p>
7210: <pre> 'NoTranslation' ';'</pre>
7211: </div>
7212:
7213: <div class="subsection">
1.37 cvs 7214: <h3><a name="sectc5219" id="sectc5219">The <tt>NoLineBreak</tt> rule</a></h3>
1.18 cvs 7215:
1.30 cvs 7216: <p>The <tt>NoLineBreak</tt> rule indicates to the translator that it must not
1.1 cvs 7217: generate additional line breaks in the output produced for the element to
1.37 cvs 7218: which it applies. This is as if it was an <a href="#sectc522">instruction
1.18 cvs 7219: <tt>LINELENGTH 0;</tt></a> at the beginning of the translation schema, but
7220: only for the current element.</p>
1.30 cvs 7221:
7222: <p>The <tt>NoLineBreak</tt> rule is written with the <tt>NoLineBreak</tt>
7223: keyword followed by a semicolon.</p>
1.18 cvs 7224: <pre> 'NoLineBreak' ';'</pre>
7225: </div>
1.1 cvs 7226:
1.18 cvs 7227: <div class="subsection">
1.37 cvs 7228: <h3><a name="sectc5220" id="sectc5220">The <tt>ChangeMainFile</tt>
7229: rule</a></h3>
1.1 cvs 7230:
1.30 cvs 7231: <p>When the translation program starts, it opens a main output file, whose
1.37 cvs 7232: name is given as a parameter of the translator. All <a
7233: href="#sectc5210"><tt>Create</tt> rules</a> without explicit indication of
7234: the output file write sequentially in this file. When a
7235: <tt>ChangeMainFile</tt> rule is executed, the main output file is closed and
7236: it is replaced by a new one, whose name is specified in the
7237: <tt>ChangeMainFile</tt> rule. The <tt>Create</tt> rules without indication of
7238: the output file that are then executed write in this new file. Several
7239: <tt>ChangeMainFile</tt> rules can be executed during the same translation,
7240: for dividing the main output into several files.</p>
1.30 cvs 7241:
7242: <p>This rule is written with the <tt>ChangeMainFile</tt> keyword followed by
7243: the name of a variable that specifies the name of the new main file. The
1.37 cvs 7244: keyword <tt>Before</tt> or <tt>After</tt> can be placed at the end of the
7245: rule to specify whether the operation should be performed before or after
7246: translation of the rule's element (the default is before). This rule, like
7247: all translation rules, is terminated by a semicolon.</p>
1.18 cvs 7248: <pre> 'ChangeMainFile' VarID [ Position ] ';'</pre>
1.30 cvs 7249:
1.18 cvs 7250: <blockquote class="example">
1.30 cvs 7251: <p><strong>Example:</strong></p>
7252:
7253: <p>To generate the translation of each section in a different file, the
1.37 cvs 7254: following rule can be associated with type <tt>Section</tt>. That rule uses
1.30 cvs 7255: the <a href="#varoutputfile"><tt>VarOutpuFile</tt> variable</a> defined
7256: above.</p>
7257: <pre> Section:
1.18 cvs 7258: ChangeMainFile VarOutpuFile Before;</pre>
1.30 cvs 7259:
7260: <p>If <tt>output.txt</tt> is the name of the output file specified when
7261: starting the translation program, translated sections are written in files
7262: <tt>output1.txt</tt>, <tt>output2.txt</tt>, etc.</p>
1.18 cvs 7263: </blockquote>
7264: </div>
1.1 cvs 7265:
1.18 cvs 7266: <div class="subsection">
1.37 cvs 7267: <h3><a name="sectc5220a" id="sectc5220a">The <tt>RemoveFile</tt> rule</a></h3>
1.14 cvs 7268:
1.37 cvs 7269: <p>Files may be used for storing temporary data that are no longer needed
7270: when the translation of a document is complete. These files may be removed by
7271: the <tt>RemoveFile</tt> rule.</p>
1.30 cvs 7272:
7273: <p>This rule is written with the <tt>RemoveFile</tt> keyword followed by the
1.37 cvs 7274: name of a variable that specifies the name of the file to be removed. The
7275: keyword <tt>Before</tt> or <tt>After</tt> can be placed at the end of the
7276: rule to specify whether the operation should be performed before or after
7277: translation of the rule's element (the default is before). This rule, like
1.30 cvs 7278: all translation rules, is terminated by a semicolon.</p>
1.18 cvs 7279: <pre> 'RemoveFile' VarID [ Position ] ';'</pre>
7280: </div>
7281:
7282: <div class="subsection">
1.37 cvs 7283: <h3><a name="sectc5221" id="sectc5221">The <tt>Set</tt> and <tt>Add</tt>
7284: rules</a></h3>
1.18 cvs 7285:
1.37 cvs 7286: <p>The <tt>Set</tt> and <tt>Add</tt> rules are used for modifying the value
7287: of counters that have no <a href="#sectc524">counting function</a>. Only this
1.18 cvs 7288: type of counter can be used in the <tt>Set</tt> and <tt>Add</tt> rules.</p>
1.30 cvs 7289:
7290: <p>Both rules have the same syntax: after the keyword <tt>Set</tt> or
1.18 cvs 7291: <tt>Add</tt> appear the counter name and the value to assign to the counter
7292: (<tt>Set</tt> rule) or the value to be added to the counter (<tt>Add</tt>
1.37 cvs 7293: rule). The keyword <tt>Before</tt> or <tt>After</tt> can follow that value to
1.1 cvs 7294: indicate when the rule must be applied: before or after the element's content
1.37 cvs 7295: is translated. By default, <tt>Before</tt> is assumed. A semicolon terminates
1.18 cvs 7296: the rule.</p>
7297: <pre> 'Set' CounterID InitValue [ Position ] ';' /
7298: 'Add' CounterID Increment [ Position ] ';'</pre>
7299: </div>
7300:
7301: <div class="subsection">
1.37 cvs 7302: <h3><a name="sectc5221a" id="sectc5221a">The <tt>Indent</tt> rule</a></h3>
1.18 cvs 7303:
1.37 cvs 7304: <p>The <tt>Indent</tt> rule is used to modify the value of text indentation
7305: in the output files.</p>
1.30 cvs 7306:
1.37 cvs 7307: <p>Each time the translator creates a new line in an output file, it
7308: generates a variable number of space characters at the beginning of the new
7309: line. By default, the number of these characters (the indentation value) is
7310: 0. It can be changed with the <tt>Indent</tt> rule.</p>
1.30 cvs 7311:
7312: <p>In its simple form, the rule begins with the <tt>Indent</tt> keyword,
1.25 cvs 7313: followed by the indentation sign (optional) and value and a keyword
1.30 cvs 7314: <tt>Before</tt> or <tt>After</tt> indicating that the indentation should be
7315: changed <a href="#sectc5222">before or after</a> the element's content is
1.37 cvs 7316: generated. If the position is not indicated, the indentation is changed
7317: before the element's content is generated. This rule, like all translation
1.25 cvs 7318: rules, is terminated by a semicolon.</p>
1.30 cvs 7319:
7320: <p>The indentation value is indicated by an integer, which is the number of
7321: space characters to be generated at the beginning of each new line. A sign
1.18 cvs 7322: (<tt>+</tt> or <tt>-</tt>) can appear before the integer to indicate that the
1.37 cvs 7323: value is relative: the current value of indentation is incremented (if sign
7324: is <tt>+</tt>) or decremented (if sign is <tt>-</tt>) by the specified
7325: value.</p>
1.30 cvs 7326:
7327: <p>Keyword <tt>Suspend</tt> or <tt>Resume</tt> can appear instead of the
1.37 cvs 7328: (possibly signed) identation value. <tt>Suspend</tt> means that the new
1.30 cvs 7329: indentation value to be used is zero until another <tt>Indent</tt> rule is
7330: executed and changes the indentation value. <tt>Resume</tt> means that the
7331: indentation value that was used before the last <tt>Indent Suspend</tt> was
1.37 cvs 7332: executed becomes the new value. Only one <tt>Suspend</tt> can be used before
1.30 cvs 7333: a <tt>Resume</tt>; <tt>Supend</tt>-<tt>Resume</tt> pairs can not be
7334: nested.</p>
7335:
1.37 cvs 7336: <p>Like the <a href="#sectc5210"><tt>Create</tt> rule</a>, the
7337: <tt>Indent</tt> keyword can be followed by the <tt>IN</tt> keyword and by the
7338: name of a <a href="#sectc526">variable</a>. This means that the rule must not
7339: change indentation in the main output file, but in the file whose name is
7340: specified by the variable (by default, indentation is changed in the main
7341: output file).</p>
1.25 cvs 7342: <pre> 'Indent' [ 'IN' VarID ] Indent [ Position ] ';' .
1.10 cvs 7343:
1.25 cvs 7344: Indent = 'Suspend' / 'Resume' / [ IndentSign ] IndentValue .
1.10 cvs 7345: IndentSign = '+' / '-' .
1.18 cvs 7346: IndentValue = NUMBER .</pre>
7347: </div>
1.10 cvs 7348:
1.18 cvs 7349: <div class="subsection">
1.37 cvs 7350: <h3><a name="sectc5222" id="sectc5222">Rule application order</a></h3>
1.1 cvs 7351:
1.30 cvs 7352: <p>The translator translates the elements which comprise the document in the
1.37 cvs 7353: order induced by the tree structure, except when the <tt>Get</tt> rule is
7354: used to change the order of translation. For each element, the translator
7355: first applies the rules specified for the element's type that must be applied
7356: before translation of the element's content (rules ending with the
7357: <tt>Before</tt> keyword or which have no position keyword). If several rules
7358: meet these criteria, the translator applies them in the order in where they
7359: appear in the translation schema.</p>
7360:
7361: <p>It then applies all <a href="#sectc5223">rules for the attributes</a>
7362: which the element has and which must be applied before the translation of the
7363: element's content (rules ending with the <tt>Before</tt> keyword or which
7364: have no position keyword). For one attribute value, the translator applies
7365: the rules in the order in which they are defined in the translation
7366: schema.</p>
1.30 cvs 7367:
7368: <p>The same procedure is followed with translation rules for specific
1.18 cvs 7369: presentations.</p>
1.30 cvs 7370:
1.31 cvs 7371: <p>Next, the element's content is translated, as long as a <tt>Remove</tt> or
7372: <code>Ignore</code> rule does not apply.</p>
1.30 cvs 7373:
7374: <p>In the next step, the translator applies rules for the specific
7375: presentation of the element that are to be applied after translation of the
1.37 cvs 7376: content (rules which end with the <tt>After</tt> keyword). The rules for each
1.30 cvs 7377: type of presentation rule or each value are applied in the order in which the
1.18 cvs 7378: translation appear in the schema.</p>
1.30 cvs 7379:
7380: <p>Then, the same procedure is followed for translation rules for attributes
7381: of the element.</p>
7382:
1.37 cvs 7383: <p>Finally, the translator applies rules for the element which must be
7384: applied after translation of the element's content. These rules are applied
7385: in the order that they appear in the translation schema. When the translation
7386: of an element is done, the translator procedes to translate the following
1.18 cvs 7387: element.</p>
1.30 cvs 7388:
7389: <p>This order can be changed with the <tt>Attributes</tt> and
1.18 cvs 7390: <tt>Presentation</tt> options of the <a href="#sectc5210"><tt>Create</tt>
7391: rule</a>.</p>
7392: </div>
1.1 cvs 7393:
1.18 cvs 7394: <div class="subsection">
1.37 cvs 7395: <h3><a name="sectc5223" id="sectc5223">Translation of logical
7396: attributes</a></h3>
1.1 cvs 7397:
1.37 cvs 7398: <p>After the rules for the element types, the translation schema defines
7399: rules for attribute values. This section begins with the <tt>ATTRIBUTES</tt>
1.1 cvs 7400: keyword and is composed of a sequence of rule blocks each preceded by an
1.18 cvs 7401: attribute name and an optional value or value range.</p>
1.30 cvs 7402:
7403: <p>If the attribute's name appears alone before the rule block, the rule are
1.1 cvs 7404: applied to all element which have the attribute, no matter what value the
1.37 cvs 7405: attribute has. In this case, the attribute name is followed by a colon before
1.18 cvs 7406: the beginning of the rule block.</p>
1.30 cvs 7407:
1.37 cvs 7408: <p>The attribute's name can be followed by the name of an element type
7409: between parentheses. This says, as in presentation schemas, that the rule
7410: block which follows applies not to the element which has the attribute, but
7411: to its descendants of the type indicated between the parentheses.</p>
1.30 cvs 7412:
7413: <p>If values are given after the attribute name (or after the name of the
1.37 cvs 7414: element type), the rules are applied only when the attribute has the
7415: indicated values. The same attribute can appear several times, with different
7416: values and different translation rules. Attribute values are indicated in the
7417: same way as in <a href="#sectc528">conditions</a> and are followed by a colon
7418: before the block of rules.</p>
1.30 cvs 7419:
7420: <p>The rule block associated with an attribute is either a simple rule or a
1.18 cvs 7421: sequence of rules delimited by the <tt>BEGIN</tt> and <tt>END</tt> keywords.
7422: Note that rules associated with attribute values cannot be conditional.</p>
1.30 cvs 7423:
7424: <p>Translation rules are not required for all attributes (or their values)
1.37 cvs 7425: defined in a structure schema. Only those attributes for which a particular
7426: action must be performed by the translator must have such rules. The rules
1.18 cvs 7427: that can be used are those described above, from <a
7428: href="#sectc5210"><tt>Create</tt></a> to <a
7429: href="#sectc5218"><tt>NoTranslation</tt></a>.</p>
1.30 cvs 7430: <pre> AttrSeq = TransAttr < TransAttr > .
1.1 cvs 7431: TransAttr = AttrID [ '(' ElemID ')' ]
7432: [ RelatAttr ] ':' RuleSeq .
7433: AttrID = NAME .
1.18 cvs 7434: ElemID = NAME .</pre>
1.30 cvs 7435:
1.18 cvs 7436: <blockquote class="example">
1.30 cvs 7437: <p><strong>Example:</strong></p>
7438:
7439: <p>The structure defined the ``Language'' attribute which can take the
1.37 cvs 7440: values ``French'' and ``English''. To have the French parts of the original
1.30 cvs 7441: document removed and prevent the translation of the leaves of the English
7442: parts, the following rules would be used:</p>
7443: <pre>ATTRIBUTES
1.1 cvs 7444: Language=French :
7445: Remove;
7446: Language=English :
1.18 cvs 7447: NoTranslation;</pre>
7448: </blockquote>
7449: </div>
1.1 cvs 7450:
1.18 cvs 7451: <div class="subsection">
1.37 cvs 7452: <h3><a name="sectc5224" id="sectc5224">Translation of specific
7453: presentations</a></h3>
1.1 cvs 7454:
1.30 cvs 7455: <p>After the rules for attributes, the translation schema defines rules for
1.37 cvs 7456: the specific presentation. This section begins with the <tt>PRESENTATION</tt>
7457: keyword and is composed of a sequence of translation rule blocks each
7458: preceded by a presentation rule name, optionally accompanied by a part which
7459: depends on the particular presentation rule.</p>
1.30 cvs 7460:
7461: <p>Each of these translation rule blocks is applied when the translator
7462: operates on an element which has a specific presentation rule of the type
1.37 cvs 7463: indicated at the head of the block. Depending on the type of the specific
1.30 cvs 7464: presentation rule, it is possible to specify values of the presentation rule
7465: for which the translation rule block should be applied.</p>
7466:
7467: <p>There are three categories of the presentation rules:</p>
7468: <ul>
7469: <li>rules taking numeric values: <tt>Size</tt>, <tt>Indent</tt>,
7470: <tt>LineSpacing</tt>, <tt>LineWeight</tt>,</li>
7471: <li>rules whose values are taken from a predefined list (i.e. whose type is
1.36 cvs 7472: an enumeration): <tt>Adjust</tt>, <tt>Hyphenate,/TT>, <tt>Style</tt>,
7473: <tt>Weight</tt>, <tt>Font</tt>, <tt>UnderLine</tt>, <tt>Thickness</tt>,
7474: <tt>LineStyle</tt>,</tt></li>
1.30 cvs 7475: <li>rules whose value is a name: <tt>FillPattern</tt>, <tt>Background</tt>,
7476: <tt>Foreground</tt>.</li>
1.18 cvs 7477: </ul>
1.30 cvs 7478:
7479: <p>For presentation rules of the first category, the values which provoke
1.1 cvs 7480: application of the translation rules are indicated in the same manner as for
1.37 cvs 7481: <a href="#relattr">numeric attributes</a>. This can be either a unique value
7482: or range of values. For a unique value, the value (an integer) is simply
7483: preceded by an equals sign. Value ranges can be specified in one of three
1.18 cvs 7484: ways:</p>
7485: <ul>
1.30 cvs 7486: <li>all values less than a given value (this value is preceded by a ``less
7487: than'' sign '<tt><</tt>'),</li>
7488: <li>all values greater than a given value (this value is preceded by a`
7489: `greater than'' sign '<tt>></tt>'),</li>
1.37 cvs 7490: <li>all values falling in an interval, bounds included. The range of values
1.30 cvs 7491: is then specified <tt>IN [</tt>Minimum<tt>..</tt>Maximum<tt>]</tt>, where
7492: Minimum and Maximum are integers.</li>
1.18 cvs 7493: </ul>
1.30 cvs 7494:
7495: <p>All numeric values can be negative, in which case the integer is preceded
1.37 cvs 7496: by a minus sign. All values must be given in typographers points.</p>
1.30 cvs 7497:
7498: <p>For presentation rules whose values are taken from a predefined list, the
1.1 cvs 7499: value which provokes application of the translation rules is simply indicated
1.18 cvs 7500: by the equals sign followed by the name of the value.</p>
1.30 cvs 7501:
1.37 cvs 7502: <p>For presentation rules whose values are names, the value which provokes
7503: the application of translation rules is simply indicated by the equals sign
7504: followed by the name of the value. The names of the fill patterns (the
1.18 cvs 7505: <tt>FillPattern</tt> rule) and of the colors (the <tt>Foreground</tt> and
7506: <tt>Background</tt> rules) used in Thot are the same as in the P language.</p>
1.30 cvs 7507: <pre> PresSeq = PresTrans < PresTrans > .
1.1 cvs 7508: PresTrans = PresRule ':' RuleSeq .
7509: PresRule = 'Size' [ PresRelation ] /
7510: 'Indent' [ PresRelation ] /
7511: 'LineSpacing' [ PresRelation ] /
7512: 'Adjust' [ '=' AdjustVal ] /
7513: 'Hyphenate' [ '=' BoolVal ] /
7514: 'Style' [ '=' StyleVal ] /
1.24 cvs 7515: 'Weight' [ '=' WeightVal ] /
1.1 cvs 7516: 'Font' [ '=' FontVal ] /
7517: 'UnderLine' [ '=' UnderLineVal ] /
7518: 'Thickness' [ '=' ThicknessVal ] /
7519: 'LineStyle' [ '=' LineStyleVal ] /
7520: 'LineWeight' [ PresRelation ] /
7521: 'FillPattern' [ '=' Pattern ] /
7522: 'Background' [ '=' Color ] /
7523: 'Foreground' [ '=' Color ] .
7524:
7525: PresRelation = '=' PresValue /
1.30 cvs 7526: '>' [ '-' ] PresMinimum /
1.1 cvs 7527: '<' [ '-' ] PresMaximum /
7528: 'IN' '[' [ '-' ] PresIntervalMin '..'
7529: [ '-' ] PresIntervalMax ']' .
1.35 cvs 7530: AdjustVal = 'Left' / 'Right' / 'VMiddle' / 'Justify' /
1.1 cvs 7531: 'LeftWithDots' .
7532: BoolVal = 'Yes' / 'No' .
1.24 cvs 7533: StyleVal = 'Roman' / 'Italics' / 'Oblique' .
7534: WeightVal = 'Normal' / 'Bold' .
1.1 cvs 7535: FontVal = 'Times' / 'Helvetica' / 'Courier' .
7536: UnderLineVal = 'NoUnderline' / 'UnderLined' /
7537: 'OverLined' / 'CrossedOut' .
7538: ThicknessVal = 'Thick' / 'Thin' .
1.6 cvs 7539: LineStyleVal = 'Solid' / 'Dashed' / 'Dotted' .
1.1 cvs 7540: Pattern = NAME .
7541: Color = NAME .
7542: PresMinimum = NUMBER .
7543: PresMaximum = NUMBER .
7544: PresIntervalMin= NUMBER .
7545: PresIntervalMax= NUMBER .
7546: PresValue = [ '-' ] PresVal .
1.18 cvs 7547: PresVal = NUMBER .</pre>
1.30 cvs 7548:
1.37 cvs 7549: <p>The <a name="prestransl" id="prestransl">translation rules associated with
7550: specific presentation rules</a> can use the value of the specific
7551: presentation rule that causes them to be applied. This behavior is designated
7552: by the keyword <tt>Value</tt>. For numerically-valued presentation rules, the
7553: numeric value is produced. For other presentation rules, the name of the
7554: value is produced.</p>
1.30 cvs 7555:
7556: <p>It should be noted that modifications to the layout of the document's
7557: elements that are made using the combination of the control key and a mouse
7558: button will have no effect on the translation of the document.</p>
7559:
7560: <blockquote class="example">
7561: <p><strong>Example:</strong></p>
7562:
7563: <p>Suppose that it is desirable to use the same font sizes as in the
7564: specific presentation, but the font size must be between 10 and 18
7565: typographer's points. If font size is set in the translated document by the
7566: string <tt>pointsize=n</tt> where <tt>n</tt> is the font size in
7567: typographer's points then the following rules will suffice:</p>
7568: <pre>PRESENTATION
1.1 cvs 7569: Size < 10 :
7570: Create 'pointsize=10';
7571: Size in [10..18] :
7572: BEGIN
7573: Create 'pointsize=';
7574: Create Value;
7575: END;
1.30 cvs 7576: Size > 18 :
1.18 cvs 7577: Create 'pointsize=18';</pre>
7578: </blockquote>
7579: </div>
1.1 cvs 7580:
1.18 cvs 7581: <div class="subsection">
1.37 cvs 7582: <h3><a name="sectc5225" id="sectc5225">Recoding of characters, symbols and
7583: graphics</a></h3>
1.1 cvs 7584:
1.37 cvs 7585: <p>The coding of characters, graphical elements and symbols as defined in
7586: Thot does not necessarily correspond to what is required by an application to
7587: which a Thot document must be exported. Because of this the translator can
7588: recode these terminal elements of the documents structure. The last sections
7589: of a translation schema are intended for this purpose, each specifying the
7590: recoding rules for one type of terminal element.</p>
1.30 cvs 7591:
1.37 cvs 7592: <p>The recoding rules for character strings are grouped by alphabets. There
7593: is a group of rules for each alphabet of the Thot document that must be
1.30 cvs 7594: translated. Each such group of rules begins with the <tt>TEXTTRANSLATE</tt>
7595: keyword, followed by the specification of the alphabet to translate and the
7596: recoding rules, between the <tt>BEGIN</tt> and <tt>END</tt> keywords unless
7597: there is only one recoding rule for the alphabet. The specification of the
7598: alphabet is not required: by default it is assumed to the Latin alphabet (the
7599: ISO Latin-1 character set).</p>
7600:
7601: <p>Each recoding rule is formed by a source string between apostrophes and a
1.1 cvs 7602: target string, also between apostrophes, the two strings being separated by
1.30 cvs 7603: the arrow symbol (<tt>-></tt>), formed by the ``minus'' and ``greater
1.37 cvs 7604: than'' characters. The rule is terminated by a semi-colon.</p>
1.18 cvs 7605: <pre> TextTransSeq = [ Alphabet ] TransSeq .
1.1 cvs 7606: Alphabet = NAME .
1.30 cvs 7607: TransSeq ='BEGIN' < Translation > 'END' ';' /
1.1 cvs 7608: Translation .
1.30 cvs 7609: Translation = Source [ '->' Target ] ';' .
1.1 cvs 7610: Source = STRING .
1.18 cvs 7611: Target = STRING .</pre>
1.30 cvs 7612:
7613: <p>One such rule signifies that when the source string appears in a text leaf
7614: of the document being translated, the translator must replace it, in the
1.37 cvs 7615: translated document, with the target string. The source string and the target
7616: string can have different lengths and the target string can be empty. In this
1.1 cvs 7617: last case, the translator simply suppresses every occurrence of the source
1.18 cvs 7618: string in the translated document.</p>
1.30 cvs 7619:
7620: <p>For a given alphabet, the order of the rules is not important and has no
1.1 cvs 7621: significance because the T language compiler reorders the rules in ways that
1.37 cvs 7622: speed up the translator's work. The total number of recoding rules is limited
1.18 cvs 7623: by the compiler as is the maximum length of the source and target strings.</p>
1.30 cvs 7624:
7625: <p>The recoding rules for symbols and graphical elements are written in the
1.37 cvs 7626: same manner as the recoding rules for character strings. They are preceded,
7627: respectively, by the <tt>SYMBTRANSLATE</tt> and <tt>GRAPHTRANSLATE</tt> and
7628: so not require a specification of the alphabet. Their source string is
7629: limited to one character, since, in Thot, each symbol and each graphical
7630: element is represented by a single character. The symbol and graphical
7631: element codes are defined along with the <a href="#sect7">non-standard
7632: character codes</a>.</p>
1.30 cvs 7633:
1.18 cvs 7634: <blockquote class="example">
1.30 cvs 7635: <p><strong>Example:</strong></p>
7636:
7637: <p>In a translation schema producing documents destined for use with the
7638: L<sup>A</sup>T<sub><big>E</big></sub>X formatter, the Latin characters``é''
1.37 cvs 7639: (octal code 351 in Thot) and ``č'' (octal code 350 in Thot) must be
1.30 cvs 7640: converted to their representation in
7641: L<sup>A</sup>T<sub><big>E</big></sub>X:</p>
7642: <pre>TEXTTRANSLATE Latin
1.1 cvs 7643: BEGIN
1.30 cvs 7644: '\350' -> '\`{e}'; { e grave }
7645: '\351' -> '\''{e}'; { e acute }
1.18 cvs 7646: END;</pre>
7647: </blockquote>
7648: </div>
7649: </div>
1.37 cvs 7650: <hr />
1.18 cvs 7651: </div>
1.1 cvs 7652:
1.18 cvs 7653: <div class="chapter">
1.37 cvs 7654: <h1><a name="sect6" id="sect6">Language grammars</a></h1>
1.1 cvs 7655:
1.30 cvs 7656: <p>This chapter gives the complete grammars of the languages of Thot. The
1.1 cvs 7657: grammars were presented and described in the preceding chapters, which also
1.37 cvs 7658: specify the semantics of the languages. This section gives only the
1.18 cvs 7659: syntax.</p>
1.1 cvs 7660:
1.18 cvs 7661: <div class="section">
1.37 cvs 7662: <h2><a name="sectb61" id="sectb61">The M meta-language</a></h2>
1.1 cvs 7663:
1.30 cvs 7664: <p>The language grammars are all expressed in the same formalism, the M
1.18 cvs 7665: meta-language, which is defined in this section.</p>
7666: <pre>{ Any text between braces is a comment. }
1.30 cvs 7667: Grammar = Rule < Rule > 'END' .
7668: { The < and > signs indicate zero }
1.1 cvs 7669: { or more repetitions. }
7670: { END marks the end of the grammar. }
7671: Rule = Ident '=' RightPart '.' .
7672: { The period indicates the end of a rule }
7673: RightPart = RtTerminal / RtIntermed .
7674: { The slash indicates a choice }
7675: RtTerminal ='NAME' / 'STRING' / 'NUMBER' .
7676: { Right part of a terminal rule }
1.30 cvs 7677: RtIntermed = Possibility < '/' Possibility > .
1.1 cvs 7678: { Right part of an intermediate rule }
1.30 cvs 7679: Possibility = ElemOpt < ElemOpt > .
7680: ElemOpt = Element / '[' Element < Element > ']' /
7681: '<' Element < Element > '>' .
1.1 cvs 7682: { Brackets delimit optional parts }
7683: Element = Ident / KeyWord .
7684: Ident = NAME .
7685: { Identifier, sequence of characters
7686: KeyWord = STRING .
7687: { Character string delimited by apostrophes }
1.18 cvs 7688: END</pre>
7689: </div>
1.1 cvs 7690:
1.18 cvs 7691: <div class="section">
1.37 cvs 7692: <h2><a name="sectb62" id="sectb62">The S language</a></h2>
1.1 cvs 7693:
1.30 cvs 7694: <p>The S language is used to write structure schemas, which contain the
1.37 cvs 7695: generic logical structures of document and object classes. It is described
1.30 cvs 7696: here in the M meta-language.</p>
1.18 cvs 7697: <pre>StructSchema = 'STRUCTURE' [ 'EXTENSION' ] ElemID ';'
1.1 cvs 7698: 'DEFPRES' PresID ';'
7699: [ 'ATTR' AttrSeq ]
7700: [ 'STRUCT' RulesSeq ]
7701: [ 'EXTENS' ExtensRuleSeq ]
7702: [ 'UNITS' RulesSeq ]
7703: [ 'EXPORT' SkeletonSeq ]
7704: [ 'EXCEPT' ExceptSeq ]
7705: 'END' .
7706:
7707: ElemID = NAME .
7708: PresID = NAME .
7709:
1.30 cvs 7710: AttrSeq = Attribute < Attribute > .
1.1 cvs 7711: Attribute = AttrID '=' AttrType ';' .
7712: AttrType = 'INTEGER' / 'TEXT' /
7713: 'REFERENCE' '(' RefType ')' /
7714: ValueSeq .
7715: RefType = 'ANY' /
7716: [ FirstSec ] ElemID [ ExtStruct ] .
1.30 cvs 7717: ValueSeq = AttrVal < ',' AttrVal > .
1.1 cvs 7718: AttrID = NAME .
7719: FirstSec = 'First' / 'Second' .
7720: ExtStruct = '(' ElemID ')' .
7721: AttrVal = NAME .
7722:
1.30 cvs 7723: RulesSeq = Rule < Rule > .
1.1 cvs 7724: Rule = ElemID [ LocAttrSeq ] '='
7725: DefWithAttr ';' .
7726: LocAttrSeq = '(' 'ATTR' LocalAttr
1.30 cvs 7727: < ';' LocalAttr > ')' .
1.1 cvs 7728: LocalAttr = [ '!' ] AttrID [ '=' AttrType ] .
7729: DefWithAttr = Definition
7730: [ '+' '(' ExtensionSeq ')' ]
7731: [ '-' '(' RestrictSeq ')' ]
7732: [ 'WITH' FixedAttrSeq ] .
1.30 cvs 7733: ExtensionSeq = ExtensionElem < ',' ExtensionElem > .
1.1 cvs 7734: ExtensionElem = ElemID / 'TEXT' / 'GRAPHICS' /
7735: 'SYMBOL' / 'PICTURE' .
1.30 cvs 7736: RestrictSeq = RestrictElem < ',' RestrictElem > .
1.1 cvs 7737: RestrictElem = ElemID / 'TEXT' / 'GRAPHICS' /
7738: 'SYMBOL' / 'PICTURE' .
1.30 cvs 7739: FixedAttrSeq = FixedAttr < ',' FixedAttr > .
1.1 cvs 7740: FixedAttr = AttrID [ FixedOrModifVal ] .
7741: FixedOrModifVal= [ '?' ] '=' FixedValue .
7742: FixedValue = [ '-' ] NumValue / TextValue / AttrVal .
7743: NumValue = NUMBER .
7744: TextValue = STRING .
7745:
7746: Definition = BaseType [ LocAttrSeq ] / Constr /
7747: Element .
7748: BaseType = 'TEXT' / 'GRAPHICS' / 'SYMBOL' /
7749: 'PICTURE' / 'UNIT' / 'NATURE' .
7750: Element = ElemID [ ExtOrDef ] .
7751: ExtOrDef = 'EXTERN' / 'INCLUDED' /
7752: [ LocAttrSeq ] '=' Definition .
7753:
7754: Constr = 'LIST' [ '[' min '..' max ']' ] 'OF'
7755: '(' DefWithAttr ')' /
7756: 'BEGIN' DefOptSeq 'END' /
7757: 'AGGREGATE' DefOptSeq 'END' /
7758: 'CASE' 'OF' DefSeq 'END' /
7759: 'REFERENCE' '(' RefType ')' /
7760: 'PAIR' .
7761:
7762: min = Integer / '*' .
7763: max = Integer / '*' .
7764: Integer = NUMBER .
7765:
1.30 cvs 7766: DefOptSeq = DefOpt ';' < DefOpt ';' > .
1.1 cvs 7767: DefOpt = [ '?' ] DefWithAttr .
7768:
1.30 cvs 7769: DefSeq = DefWithAttr ';' < DefWithAttr ';' > .
1.1 cvs 7770:
1.30 cvs 7771: SkeletonSeq = SkeletonElem < ',' SkeletonElem > ';' .
1.1 cvs 7772: SkeletonElem = ElemID [ 'WITH' Contents ] .
7773: Contents = 'Nothing' / ElemID [ ExtStruct ] .
7774:
1.30 cvs 7775: ExceptSeq = Except ';' < Except ';' > .
1.1 cvs 7776: Except = [ 'EXTERN' ] [ FirstSec ] ExcTypeOrAttr ':'
7777: ExcValSeq .
7778: ExcTypeOrAttr = ElemID / AttrID .
1.30 cvs 7779: ExcValSeq = ExcValue < ',' ExcValue > .
1.1 cvs 7780: ExcValue = 'NoCut' / 'NoCreate' /
7781: 'NoHMove' / 'NoVMove' / 'NoMove' /
7782: 'NoHResize' / 'NoVResize' / 'NoResize' /
1.18 cvs 7783: 'MoveResize' /
1.1 cvs 7784: 'NewWidth' / 'NewHeight' /
7785: 'NewHPos' / 'NewVPos' /
7786: 'Invisible' / 'NoSelect' /
7787: 'Hidden' / 'ActiveRef' /
7788: 'ImportLine' / 'ImportParagraph' /
1.9 cvs 7789: 'NoPaginate' / 'ParagraphBreak' /
7790: 'HighlightChildren' / 'ExtendedSelection' /
1.36 cvs 7791: 'SelectParent' / 'ClickableSurface' /
1.29 cvs 7792: 'ReturnCreateNL' / 'ReturnCreateWithin' .
1.1 cvs 7793:
1.30 cvs 7794: ExtensRuleSeq = ExtensRule ';' < ExtensRule ';' > .
1.1 cvs 7795: ExtensRule = RootOrElem [ LocAttrSeq ]
7796: [ '+' '(' ExtensionSeq ')' ]
7797: [ '-' '(' RestrictSeq ')' ]
7798: [ 'WITH' FixedAttrSeq ] .
7799: RootOrElem = 'Root' / ElemID .
7800:
1.18 cvs 7801: END</pre>
7802: </div>
1.1 cvs 7803:
1.18 cvs 7804: <div class="section">
1.37 cvs 7805: <h2><a name="sectb63" id="sectb63">The P language</a></h2>
1.1 cvs 7806:
1.30 cvs 7807: <p>The P language is used to write presentation schemas, which define the
1.1 cvs 7808: graphical presentation rules to be applied to different classes of documents
1.37 cvs 7809: and objects. It is described here in the M meta-language.</p>
1.18 cvs 7810: <pre>PresSchema = 'PRESENTATION' ElemID ';'
1.1 cvs 7811: [ 'VIEWS' ViewSeq ]
7812: [ 'PRINT' PrintViewSeq ]
7813: [ 'COUNTERS' CounterSeq ]
7814: [ 'CONST' ConstSeq ]
7815: [ 'VAR' VarSeq ]
7816: [ 'DEFAULT' ViewRuleSeq ]
7817: [ 'BOXES' BoxSeq ]
7818: [ 'RULES' PresentSeq ]
7819: [ 'ATTRIBUTES' PresAttrSeq ]
7820: [ 'TRANSMIT' TransmitSeq ]
7821: 'END' .
7822:
7823: ElemID = NAME .
7824:
7825: ViewSeq = ViewDeclaration
1.30 cvs 7826: < ',' ViewDeclaration > ';' .
1.1 cvs 7827: ViewDeclaration = ViewID [ 'EXPORT' ] .
7828: ViewID = NAME .
7829:
1.30 cvs 7830: PrintViewSeq = PrintView < ',' PrintView > ';' .
1.37 cvs 7831: PrintView = ViewID .
1.1 cvs 7832:
1.30 cvs 7833: CounterSeq = Counter < Counter > .
1.1 cvs 7834: Counter = CounterID ':' CounterFunc ';' .
7835: CounterID = NAME .
7836: CounterFunc = 'RANK' 'OF' TypeOrPage [ SLevelAsc ]
7837: [ 'INIT' AttrID ] [ 'REINIT' AttrID ] /
1.30 cvs 7838: SetFunction < SetFunction >
7839: AddFunction < AddFunction >
1.1 cvs 7840: [ 'INIT' AttrID ] /
1.16 cvs 7841: 'RLEVEL' 'OF' ElemID .
1.1 cvs 7842: SLevelAsc = [ '-' ] LevelAsc .
7843: LevelAsc = NUMBER .
7844: SetFunction = 'SET' CounterValue 'ON' TypeOrPage .
7845: AddFunction = 'ADD' CounterValue 'ON' TypeOrPage .
7846: TypeOrPage = 'Page' [ '(' ViewID ')' ] /
1.16 cvs 7847: [ '*' ] ElemID .
1.1 cvs 7848: CounterValue = NUMBER .
7849:
1.30 cvs 7850: ConstSeq = Const < Const > .
1.1 cvs 7851: Const = ConstID '=' ConstType ConstValue ';' .
7852: ConstID = NAME .
7853: ConstType = 'Text' [ Alphabet ] / 'Symbol' /
7854: 'Graphics' / 'Picture' .
7855: ConstValue = STRING .
7856: Alphabet = NAME .
7857:
1.30 cvs 7858: VarSeq = Variable < Variable > .
1.1 cvs 7859: Variable = VarID ':' FunctionSeq ';' .
7860: VarID = NAME .
1.30 cvs 7861: FunctionSeq = Function < Function > .
1.1 cvs 7862: Function = 'DATE' / 'FDATE' /
7863: 'DocName' / 'DirName' /
1.38 ! cvs 7864: 'ElemName' / 'AttributeName' / 'AttributeValue' /
1.1 cvs 7865: ConstID / ConstType ConstValue /
7866: AttrID /
7867: 'VALUE' '(' PageAttrCtr ','
7868: CounterStyle ')' .
7869: PageAttrCtr = 'PageNumber' [ '(' ViewID ')' ] /
7870: [ MinMax ] CounterID / AttrID .
7871: CounterStyle = 'Arabic' / 'LRoman' / 'URoman' /
7872: 'Uppercase' / 'Lowercase' .
7873: MinMax = 'MaxRangeVal' / 'MinRangeVal' .
7874:
1.30 cvs 7875: BoxSeq = Box < Box > .
1.1 cvs 7876: Box = 'FORWARD' BoxID ';' /
7877: BoxID ':' ViewRuleSeq .
7878: BoxID = NAME .
7879:
1.30 cvs 7880: PresentSeq = Present < Present > .
1.1 cvs 7881: Present = [ '*' ] [ FirstSec ] ElemID ':'
7882: ViewRuleSeq .
7883: FirstSec = 'First' / 'Second' .
7884:
1.30 cvs 7885: PresAttrSeq = PresAttr < PresAttr > .
1.1 cvs 7886: PresAttr = AttrID [ '(' [ FirstSec ] ElemID ')' ]
7887: [ AttrRelation ] ':' ViewRuleSeq .
7888: AttrID = NAME .
7889: AttrRelation = '=' AttrVal /
1.30 cvs 7890: '>' [ '-' ] MinValue /
1.1 cvs 7891: '<' [ '-' ] MaxValue /
7892: 'IN' '[' [ '-' ] LowerBound '..'
7893: [ '-' ] UpperBound ']' /
7894: 'GREATER' AttrID /
7895: 'EQUAL' AttrID /
7896: 'LESS' AttrID .
7897: AttrVal = [ '-' ] EqualNum / EqualText / AttrValue .
7898: MinValue = NUMBER .
7899: MaxValue = NUMBER .
7900: LowerBound = NUMBER .
7901: UpperBound = NUMBER.
7902: EqualNum = NUMBER .
7903: EqualText = STRING .
7904: AttrValue = NAME .
7905:
1.30 cvs 7906: ViewRuleSeq = 'BEGIN' < RulesAndCond > < ViewRules >
1.1 cvs 7907: 'END' ';' /
7908: ViewRules / CondRules / Rule .
7909: RulesAndCond = CondRules / Rule .
7910: ViewRules = 'IN' ViewID CondRuleSeq .
1.30 cvs 7911: CondRuleSeq = 'BEGIN' < RulesAndCond > 'END' ';' /
1.1 cvs 7912: CondRules / Rule .
1.30 cvs 7913: CondRules = CondRule < CondRule >
1.1 cvs 7914: [ 'Otherwise' RuleSeq ] .
7915: CondRule = 'IF' ConditionSeq RuleSeq .
1.30 cvs 7916: RulesSeq = 'BEGIN' Rule < Rule > 'END' ';' / Rule .
1.1 cvs 7917:
1.30 cvs 7918: ConditionSeq = Condition < 'AND' Condition > .
1.6 cvs 7919: Condition = [ 'NOT' ] [ 'Target' ] ConditionElem .
7920: ConditionElem = 'First' / 'Last' /
7921: [ 'Immediately' ] 'Within' [ NumParent ]
7922: ElemID [ ExtStruct ] /
7923: ElemID /
7924: 'Referred' / 'FirstRef' / 'LastRef' /
7925: 'ExternalRef' / 'InternalRef' / 'CopyRef' /
7926: 'AnyAttributes' / 'FirstAttr' / 'LastAttr' /
7927: 'UserPage' / 'StartPage' / 'ComputedPage' /
1.33 cvs 7928: 'Empty' / 'Root' /
1.6 cvs 7929: '(' [ MinMax ] CounterName CounterCond ')' /
7930: CondPage '(' CounterID ')' .
7931: NumParent = [ GreaterLess ] NParent .
1.30 cvs 7932: GreaterLess = '>' / '<' .
1.6 cvs 7933: NParent = NUMBER.
1.30 cvs 7934: CounterCond = '<' MaxCtrVal / '>' MinCtrVal /
1.6 cvs 7935: '=' EqCtrVal /
7936: 'IN' '[' ['-'] MinCtrBound '..'
7937: ['-'] MaxCtrBound ']' .
7938: PageCond = 'Even' / 'Odd' / 'One' .
7939: MaxCtrVal = NUMBER .
7940: MinCtrVal = NUMBER .
7941: EqCtrVal = NUMBER .
7942: MaxCtrBound = NUMBER .
7943: MinCtrBound = NUMBER .
1.1 cvs 7944:
1.34 cvs 7945: Rule = Property ';' / PresFunc ';' .
7946: Property = 'VertRef' ':' HorizPosition /
1.1 cvs 7947: 'HorizRef' ':' VertPosition /
7948: 'VertPos' ':' VPos /
7949: 'HorizPos' ':' HPos /
7950: 'Height' ':' Extent /
7951: 'Width' ':' Extent /
7952: 'VertOverflow' ':' Boolean /
7953: 'HorizOverflow' ':' Boolean /
1.26 cvs 7954: 'MarginTop' ':' MarginWidth /
7955: 'MarginRight' ':' MarginWidth /
7956: 'MarginBottom' ':' MarginWidth /
7957: 'MarginLeft' ':' MarginWidth /
7958: 'PaddingTop' ':' PaddingWidth /
7959: 'PaddingRight' ':' PaddingWidth /
7960: 'PaddingBottom' ':' PaddingWidth /
7961: 'PaddingLeft' ':' PaddingWidth /
7962: 'BorderTopWidth' ':' BorderWidth /
7963: 'BorderRightWidth' ':' BorderWidth /
7964: 'BorderBottomWidth' ':' BorderWidth /
7965: 'BorderLeftWidth' ':' BorderWidth /
7966: 'BorderTopColor' ':' BorderColor /
7967: 'BorderRightColor' ':' BorderColor /
7968: 'BorderBottomColor' ':' BorderColor /
7969: 'BorderLeftColor' ':' BorderColor /
7970: 'BorderTopStyle' ':' BorderStyle /
7971: 'BorderRightStyle' ':' BorderStyle /
7972: 'BorderBottomStyle' ':' BorderStyle /
7973: 'BorderLeftStyle' ':' BorderStyle .
1.1 cvs 7974: 'LineSpacing' ':' DistOrInherit /
7975: 'Indent' ':' DistOrInherit /
7976: 'Adjust' ':' AlignOrInherit /
7977: 'Hyphenate' ':' BoolInherit /
7978: 'PageBreak' ':' Boolean /
7979: 'LineBreak' ':' Boolean /
7980: 'InLine' ':' Boolean /
7981: 'NoBreak1' ':' AbsDist /
7982: 'NoBreak2' ':' AbsDist /
7983: 'Gather' ':' Boolean /
7984: 'Visibility' ':' NumberInherit /
7985: 'Size' ':' SizeInherit /
7986: 'Font' ':' NameInherit /
7987: 'Style' ':' StyleInherit /
1.23 cvs 7988: 'Weight' ':' WeightInherit /
1.1 cvs 7989: 'Underline' ':' UnderLineInherit /
7990: 'Thickness' ':' ThicknessInherit /
7991: 'Depth' ':' NumberInherit /
7992: 'LineStyle' ':' LineStyleInherit /
7993: 'LineWeight' ':' DistOrInherit /
7994: 'FillPattern' ':' NameInherit /
1.30 cvs 7995: 'Background' ':' Color /
7996: 'Foreground' ':' Color /
1.1 cvs 7997: 'Content' ':' VarConst .
7998: PresFunc = Creation '(' BoxID ')' /
7999: 'Line' /
8000: 'NoLine' /
8001: 'Page' '(' BoxID ')' /
1.13 cvs 8002: 'Copy' '(' BoxTypeToCopy ')' /
8003: 'ShowBox' /
1.18 cvs 8004: 'BackgroundPicture' ':' FileName /
8005: 'PictureMode' ':' PictMode .
1.1 cvs 8006:
8007: BoxTypeToCopy = BoxID [ ExtStruct ] /
8008: ElemID [ ExtStruct ] .
8009: ExtStruct = '(' ElemID ')' .
8010:
8011: Distance = [ Sign ] AbsDist .
8012: Sign = '+' / '-' .
8013: AbsDist = IntegerOrAttr [ '.' DecimalPart ]
8014: [ Unit ] .
8015: IntegerOrAttr = IntegerPart / AttrID .
8016: IntegerPart = NUMBER .
8017: DecimalPart = NUMBER .
8018: Unit = 'em' / 'ex' / 'cm' / 'mm' / 'in' / 'pt' /
8019: 'pc' / 'px' / '%' .
8020:
8021: HPos = 'nil' / VertAxis '=' HorizPosition
8022: [ 'UserSpecified' ] .
8023: VPos = 'nil' / HorizAxis '=' VertPosition
8024: [ 'UserSpecified' ] .
8025: VertAxis = 'Left' / 'VMiddle' / 'VRef' / 'Right' .
8026: HorizAxis = 'Top' / 'HMiddle' / 'HRef' / 'Bottom' .
8027:
1.6 cvs 8028: VertPosition = Reference '.' HorizAxis [ Distance ] .
8029: HorizPosition = Reference '.' VertAxis [ Distance ] .
8030: Reference = 'Enclosing' [ BoxTypeNot ] /
8031: 'Enclosed' [ BoxTypeNot ] /
8032: 'Previous' [ BoxTypeNot ] /
8033: 'Next' [ BoxTypeNot ] /
8034: 'Referred' [ BoxTypeNot ] /
8035: 'Creator' /
8036: 'Root' /
8037: '*' /
8038: BoxOrType .
8039: BoxOrType = BoxID /
8040: [ '*' ] [ FirstSec ] ElemID /
1.17 cvs 8041: 'AnyElem' / 'AnyBox' /
8042: 'ElemWithAttr' AttrID .
1.6 cvs 8043: BoxTypeNot = [ 'NOT' ] BoxOrType .
8044:
8045: Extent = Reference '.' HeightWidth
8046: [ Relation ] [ 'Min' ] /
8047: AbsDist [ 'UserSpecified' ] [ 'Min' ] /
8048: HPos / VPos .
8049: HeightWidth = 'Height' / 'Width' .
8050: Relation = '*' ExtentAttr '%' / Distance .
8051: ExtentAttr = ExtentVal / AttrID .
8052: ExtentVal = NUMBER .
1.26 cvs 8053:
8054: MarginWidth = InheritParent / 'Auto' / Distance .
8055: PaddingWidth = InheritParent / Distance .
8056: BorderWidth = InheritParent / 'Thin' / 'Medium' / 'Thick' / Distance .
8057: BorderColor = InheritParent / 'Transparent' / 'Foreground' /
8058: ColorName .
8059: BorderStyle = InheritParent /
8060: 'None' / 'Hidden' / 'Dotted' / 'Dashed' / 'Solid' /
8061: 'Double' / 'Groove' / 'Ridge' / 'Inset' / 'Outset' .
1.27 cvs 8062: InheritParent = 'Enclosing' '=' / 'Creator' '=' .
1.26 cvs 8063: ColorName = NAME .
1.6 cvs 8064:
8065: Inheritance = Kinship InheritedValue .
8066: Kinship = 'Enclosing' / 'GrandFather'/ 'Enclosed' /
8067: 'Previous' / 'Creator' .
8068: InheritedValue = '+' PosIntAttr [ 'Max' maximumA ] /
8069: '-' NegIntAttr [ 'Min' minimumA ] /
8070: '=' .
8071: PosIntAttr = PosInt / AttrID .
8072: PosInt = NUMBER .
8073: NegIntAttr = NegInt / AttrID .
8074: NegInt = NUMBER .
8075: maximumA = maximum / AttrID .
8076: maximum = NUMBER .
8077: minimumA = minimum / AttrID .
8078: minimum = NUMBER .
8079:
8080: AlignOrInherit = Kinship '=' / Alignment .
8081: Alignment = 'Left' / 'Right' / 'VMiddle' /
8082: 'LeftWithDots' .
1.1 cvs 8083:
1.6 cvs 8084: DistOrInherit = Kinship InheritedDist / Distance .
8085: InheritedDist = '=' / '+' AbsDist / '-' AbsDist .
1.1 cvs 8086:
1.6 cvs 8087: BoolInherit = Boolean / Kinship '=' .
8088: Boolean = 'Yes' / 'No' .
1.1 cvs 8089:
1.6 cvs 8090: NumberInherit = Integer / AttrID / Inheritance .
8091: Integer = NUMBER .
1.1 cvs 8092:
8093: LineStyleInherit= Kinship '=' / 'Solid' / 'Dashed' /
8094: 'Dotted' .
8095:
1.6 cvs 8096: SizeInherit = SizeAttr [ 'pt' ] / Kinship InheritedSize .
8097: InheritedSize = '+' SizeAttr [ 'pt' ]
8098: [ 'Max' MaxSizeAttr ] /
8099: '-' SizeAttr [ 'pt' ]
8100: [ 'Min' MinSizeAttr ] /
1.22 cvs 8101: '*' PercentSizeAttr '%' /
1.6 cvs 8102: '=' .
8103: SizeAttr = Size / AttrID .
8104: Size = NUMBER .
8105: MaxSizeAttr = MaxSize / AttrID .
8106: MaxSize = NUMBER .
8107: MinSizeAttr = MinSize / AttrID .
8108: MinSize = NUMBER .
1.22 cvs 8109: PercentSizeAttr = PercentSize / AttrID .
8110: PercentSize = NUMBER .
1.6 cvs 8111:
8112: NameInherit = Kinship '=' / FontName .
8113: FontName = NAME .
1.30 cvs 8114: Color = 'Transparent' / Kinship '=' / FontName .
1.6 cvs 8115: StyleInherit = Kinship '=' /
1.23 cvs 8116: 'Roman' / 'Italics' / 'Oblique' .
8117: WeightInherit = Kinship '=' /
8118: 'Normal' / 'Bold' .
1.1 cvs 8119: UnderLineInherit= Kinship '=' /
1.6 cvs 8120: 'NoUnderline' / 'Underlined' /
8121: 'Overlined' / 'CrossedOut' .
1.1 cvs 8122: ThicknessInherit= Kinship '=' / 'Thick' / 'Thin' .
1.13 cvs 8123:
8124: FileName = STRING .
8125: PictMode = 'NormalSize' / 'Scale' /
8126: 'RepeatXY' / 'RepeatX' / 'RepeatY' .
1.1 cvs 8127:
1.6 cvs 8128: VarConst = ConstID / ConstType ConstValue /
8129: VarID / '(' FunctionSeq ')' /
8130: ElemID .
8131:
8132: Creation = Create [ 'Repeated' ] .
8133: Create = 'CreateFirst' / 'CreateLast' /
8134: 'CreateBefore' / 'CreateAfter' /
8135: 'CreateEnclosing' .
8136:
1.30 cvs 8137: TransmitSeq = Transmit < Transmit > .
1.6 cvs 8138: Transmit = TypeOrCounter 'To' ExternAttr
8139: '(' ElemID ')' ';' .
8140: TypeOrCounter = CounterID / ElemID .
8141: ExternAttr = NAME .
1.1 cvs 8142:
1.18 cvs 8143: END</pre>
8144: </div>
1.1 cvs 8145:
1.18 cvs 8146: <div class="section">
1.37 cvs 8147: <h2><a name="sectb64" id="sectb64">The T language</a></h2>
1.18 cvs 8148: <pre>TransSchema = 'TRANSLATION' ElemID ';'
1.1 cvs 8149: [ 'LINELENGTH' LineLength ';' ]
8150: [ 'LINEEND' CHARACTER ';' ]
8151: [ 'LINEENDINSERT' STRING ';' ]
8152: [ 'BUFFERS' BufferSeq ]
8153: [ 'COUNTERS' CounterSeq ]
8154: [ 'CONST' ConstSeq ]
8155: [ 'VAR' VariableSeq ]
8156: 'RULES' ElemSeq
8157: [ 'ATTRIBUTES' AttrSeq ]
8158: [ 'PRESENTATION' PresSeq ]
1.30 cvs 8159: < 'TEXTTRANSLATE' TextTransSeq >
1.1 cvs 8160: [ 'SYMBTRANSLATE' TransSeq ]
8161: [ 'GRAPHTRANSLATE' TransSeq ]
8162: 'END' .
8163:
8164: LineLength = NUMBER .
8165:
1.30 cvs 8166: BufferSeq = Buffer < Buffer > .
1.1 cvs 8167: Buffer = BufferID [ '(' 'Picture' ')' ] ';' .
8168: BufferID = NAME .
8169:
1.30 cvs 8170: CounterSeq = Counter < Counter > .
1.1 cvs 8171: Counter = CounterID [ ':' CounterFunc ] ';' .
8172: CounterID = NAME .
8173: CounterFunc = 'Rank' 'of' ElemID [ SLevelAsc ]
8174: [ 'Init' AttrID ] /
8175: 'Rlevel' 'of' ElemID /
8176: 'Set' InitValue 'On' ElemID
8177: 'Add' Increment 'On' ElemID
8178: [ 'Init' AttrID ] .
8179: SLevelAsc = [ '-' ] LevelAsc .
8180: LevelAsc = NUMBER .
8181: InitValue = NUMBER .
8182: Increment = NUMBER .
8183: ElemID = NAME .
8184: AttrID = NAME .
8185:
1.30 cvs 8186: ConstSeq = Const < Const > .
1.1 cvs 8187: Const = ConstID '=' ConstValue ';' .
8188: ConstID = NAME .
8189: ConstValue = STRING .
8190:
1.30 cvs 8191: VariableSeq = Variable < Variable > .
8192: Variable = VarID ':' Function < Function > ';' .
1.1 cvs 8193: VarID = NAME .
8194: Function = 'Value' '(' CounterID [ ':' Length ]
8195: [ ',' CounterStyle ] ')' /
8196: 'FileDir' / 'FileName' / 'Extension' /
8197: 'DocumentName' / 'DocumentDir' /
8198: ConstID / CharString /
8199: BufferID / AttrID .
8200: Length = NUMBER .
8201: CounterStyle= 'Arabic' / 'LRoman' / 'URoman' /
8202: 'Uppercase' / 'Lowercase' .
8203: CharString = STRING .
8204:
1.30 cvs 8205: ElemSeq = TransType < TransType > .
1.1 cvs 8206: TransType = [ FirstSec ] ElemID ':' RuleSeq .
8207: FirstSec = 'First' / 'Second' .
1.30 cvs 8208: RuleSeq = Rule / 'BEGIN' < Rule > 'END' ';' .
1.1 cvs 8209: Rule = SimpleRule / ConditionBlock .
8210: ConditionBlock= 'IF' ConditionSeq SimpleRuleSeq .
1.30 cvs 8211: SimpleRuleSeq = 'BEGIN' < SimpleRule > 'END' ';' /
1.1 cvs 8212: SimpleRule .
8213:
8214: ConditionSeq = Condition [ 'AND' Condition ] .
8215: Condition = [ 'NOT' ] [ 'Target' ] Cond .
8216: Cond = CondElem / CondAscend .
8217: CondElem = 'FirstRef' / 'LastRef' /
8218: 'ExternalRef' /
8219: 'Alphabet' '=' Alphabet /
8220: 'ComputedPage' / 'StartPage' /
8221: 'UserPage' / 'ReminderPage' /
8222: 'Empty' /
1.18 cvs 8223: ElemID /
1.1 cvs 8224: 'FirstAttr' / 'LastAttr' .
8225: CondAscend = [ Ascend ] CondOnAscend .
8226: Ascend = '*' / 'Parent' / 'Ancestor' LevelOrType .
8227: LevelOrType = CondRelLevel / ElemID [ ExtStruct ] .
8228: CondRelLevel = NUMBER .
8229: CondOnAscend = 'First' / 'Last' /
8230: 'Referred' /
8231: [ 'Immediately' ] 'Within' [ NumParent ]
8232: ElemID [ ExtStruct ] /
8233: 'Attributes' /
8234: AttrID [ RelatAttr ] /
8235: 'Presentation' /
1.34 cvs 8236: PresRule .
1.1 cvs 8237: NumParent = [ GreaterLess ] NParent .
1.30 cvs 8238: GreaterLess = '>' / '<' .
1.1 cvs 8239: NParent = NUMBER.
8240: Alphabet = NAME .
8241: RelatAttr = '=' Value /
1.30 cvs 8242: '>' [ '-' ] Minimum /
1.1 cvs 8243: '<' [ '-' ] Maximum /
8244: 'IN' '[' [ '-' ] MinInterval '..'
8245: [ '-' ] MaxInterval ']' .
8246: Value = [ '-' ] IntegerVal / TextVal / AttrValue .
8247: Minimum = NUMBER .
8248: Maximum = NUMBER .
8249: MinInterval = NUMBER .
8250: MaxInterval = NUMBER .
8251: IntegerVal = NUMBER .
8252: TextVal = STRING .
8253: AttrValue = NAME .
8254:
8255: SimpleRule = 'Create' [ 'IN' VarID ] Object
8256: [ Position ] ';' /
8257: 'Write' Object [ Position ] ';' /
8258: 'Read' BufferID [ Position ] ';' /
8259: 'Include' File [ Position ] ';' /
1.6 cvs 8260: 'Get' [ RelPosition ] ElemID
8261: [ ExtStruct ]
8262: [ Position ] ';' /
1.1 cvs 8263: 'Copy' [ RelPosition ] ElemID
8264: [ ExtStruct ]
8265: [ Position ] ';' /
8266: 'Use' TrSchema [ 'For' ElemID ] ';' /
8267: 'Remove' ';' /
1.31 cvs 8268: 'Ignore' ';' /
1.1 cvs 8269: 'NoTranslation' ';' /
8270: 'NoLineBreak' ';' /
8271: 'ChangeMainFile' VarID [ Position ] ';' /
1.14 cvs 8272: 'RemoveFile' VarID [ Position ] ';' /
1.10 cvs 8273: 'Set' CounterID InitValue [ Position ] ';' /
8274: 'Add' CounterID Increment [ Position ] ';' /
1.25 cvs 8275: 'Indent' [ 'IN' VarID ] Indent [ Position ] ';' .
1.10 cvs 8276:
1.25 cvs 8277: Indent = 'Suspend' / 'Resume' / [ IndentSign ] IndentValue .
1.10 cvs 8278: IndentSign = '+' / '-' .
8279: IndentValue = NUMBER .
1.1 cvs 8280:
8281: Object = ConstID / CharString /
8282: BufferID /
8283: VarID /
1.30 cvs 8284: '(' Function < Function > ')' /
1.21 cvs 8285: [ 'Translated' ] AttrID /
1.1 cvs 8286: 'Value' /
8287: 'Content' /
8288: 'Attributes' /
8289: 'Presentation' /
8290: 'RefId' /
8291: 'PairId' /
8292: 'FileDir' / 'FileName' / 'Extension' /
8293: 'DocumentName' / 'DocumentDir' /
8294: [ 'Referred' ] ReferredObject .
8295: Position = 'After' / 'Before' .
8296:
1.6 cvs 8297: ReferredObject= VarID /
8298: ElemID [ ExtStruct ] /
8299: 'RefId' /
8300: 'DocumentName' / 'DocumentDir' .
1.1 cvs 8301:
1.6 cvs 8302: File = FileName / BufferID .
8303: FileName = STRING .
1.1 cvs 8304:
1.6 cvs 8305: RelPosition = 'Included' / 'Referred' .
8306: ExtStruct = '(' ElemID ')' .
1.1 cvs 8307:
1.6 cvs 8308: TrSchema = NAME .
8309:
1.30 cvs 8310: AttrSeq = TransAttr < TransAttr > .
1.6 cvs 8311: TransAttr = AttrID [ '(' ElemID ')' ]
8312: [ RelatAttr ] ':' RuleSeq .
8313:
1.30 cvs 8314: PresSeq = PresTrans < PresTrans > .
1.6 cvs 8315: PresTrans = PresRule ':' RuleSeq .
8316: PresRule = 'Size' [ PresRelation ] /
8317: 'Indent' [ PresRelation ] /
8318: 'LineSpacing' [ PresRelation ] /
8319: 'Adjust' [ '=' AdjustVal ] /
8320: 'Hyphenate' [ '=' BoolVal ] /
8321: 'Style' [ '=' StyleVal ] /
1.24 cvs 8322: 'Weight' [ '=' WeightVal ] /
1.6 cvs 8323: 'Font' [ '=' FontVal ] /
8324: 'UnderLine' [ '=' UnderLineVal ] /
8325: 'Thickness' [ '=' ThicknessVal ] /
8326: 'LineStyle' [ '=' LineStyleVal ] /
8327: 'LineWeight' [ PresRelation ] /
8328: 'FillPattern' [ '=' Pattern ] /
8329: 'Background' [ '=' Color ] /
8330: 'Foreground' [ '=' Color ] .
8331:
8332: PresRelation = '=' PresValue /
1.30 cvs 8333: '>' [ '-' ] PresMinimum /
1.6 cvs 8334: '<' [ '-' ] PresMaximum /
8335: 'IN' '[' [ '-' ] PresIntervalMin '..'
8336: [ '-' ] PresIntervalMax ']' .
1.35 cvs 8337: AdjustVal = 'Left' / 'Right' / 'VMiddle' / 'Justify' /
1.6 cvs 8338: 'LeftWithDots' .
8339: BoolVal = 'Yes' / 'No' .
1.24 cvs 8340: StyleVal = 'Roman' / 'Italics' / 'Oblique' .
8341: WeightVal = 'Normal' / 'Bold' .
1.6 cvs 8342: FontVal = 'Times' / 'Helvetica' / 'Courier' .
8343: UnderLineVal = 'NoUnderline' / 'UnderLined' /
8344: 'OverLined' / 'CrossedOut' .
8345: ThicknessVal = 'Thick' / 'Thin' .
8346: LineStyleVal = 'Solid' / 'Dashed' / 'Dotted' .
8347: Pattern = NAME .
8348: Color = NAME .
8349: PresMinimum = NUMBER .
8350: PresMaximum = NUMBER .
1.1 cvs 8351: PresIntervalMin= NUMBER .
8352: PresIntervalMax= NUMBER .
1.6 cvs 8353: PresValue = [ '-' ] PresVal .
8354: PresVal = NUMBER .
1.1 cvs 8355:
1.6 cvs 8356: TextTransSeq = [ Alphabet ] TransSeq .
8357: Alphabet = NAME .
1.30 cvs 8358: TransSeq = 'BEGIN' < Translation > 'END' ';' /
1.6 cvs 8359: Translation .
1.30 cvs 8360: Translation = Source [ '->' Target ] ';' .
1.6 cvs 8361: Source = STRING .
1.18 cvs 8362: Target = STRING .</pre>
8363: </div>
1.37 cvs 8364: <hr />
1.18 cvs 8365: </div>
1.1 cvs 8366:
1.18 cvs 8367: <div class="chapter">
1.37 cvs 8368: <h1><a name="sect7" id="sect7">Character coding</a></h1>
1.1 cvs 8369:
1.18 cvs 8370: <div class="section">
1.37 cvs 8371: <h2><a name="sectb71" id="sectb71">Characters</a></h2>
1.1 cvs 8372:
1.37 cvs 8373: <p>The characters of the Latin alphabet follow the encoding defined in the
8374: ISO 8859-1 (ISO Latin-1) standard. The characters of the Greek alphabet
8375: follow the encoding defined by Adobe for its Symbol font (Adobe
8376: FontSpecific).</p>
8377:
8378: <p>Characters whose octal code is greater than 0200 are written in the form
8379: of their octal code preceded by a backslash character (``\''). For example,
8380: the French word 'Résumé' is written <tt>R\351sum\351</tt>.</p>
1.30 cvs 8381:
8382: <p>To the ISO 8859-1 encoding four characters with the following codes have
1.37 cvs 8383: been added:<br />
8384: <tt>212</tt>: line break<br />
8385: <tt>240</tt>: sticky space<br />
8386: <tt>201</tt>: thin space<br />
1.18 cvs 8387: <tt>202</tt>: en space</p>
1.30 cvs 8388:
8389: <p>The <tt>212</tt> character is a ``line break'' character which forces a
1.37 cvs 8390: line break. The <tt>240</tt> character is a ``sticky space'', which cannot be
1.18 cvs 8391: replaced by a line break.</p>
8392: </div>
1.1 cvs 8393:
1.18 cvs 8394: <div class="section">
1.37 cvs 8395: <h2><a name="sectb72" id="sectb72">Symbols</a></h2>
1.1 cvs 8396:
1.37 cvs 8397: <p>The table below gives the codes for the symbols of Thot. Symbols can be
8398: used in presentation schemas constants and in transcoding rules of
8399: translation schemas. Each symbol is represented by a single character.</p>
1.18 cvs 8400: <ul>
1.30 cvs 8401: <li><tt>r</tt>: a radical</li>
8402: <li><tt>i</tt>: a simple integral</li>
8403: <li><tt>c</tt>: a curvilinear integral</li>
8404: <li><tt>d</tt>: a double integral</li>
8405: <li><tt>t</tt>: a triple integral</li>
8406: <li><tt>S</tt>: the summation symbol</li>
8407: <li><tt>P</tt>: the product symbol</li>
8408: <li><tt>U</tt>: the union symbol</li>
8409: <li><tt>I</tt>: the intersection symbol</li>
8410: <li><tt>></tt>: a right arrow</li>
8411: <li><tt><</tt>: a left arrow</li>
1.37 cvs 8412: <li><tt>^</tt>: an up arrow</li>
1.30 cvs 8413: <li><tt>V</tt>: a down arrow</li>
8414: <li><tt>(</tt>: an opening parenthesis</li>
8415: <li><tt>)</tt>: a closing parenthesis</li>
8416: <li><tt>{</tt>: an opening brace</li>
8417: <li><tt>}</tt>: a closing brace</li>
8418: <li><tt>[</tt>: an opening bracket</li>
8419: <li><tt>]</tt>: a closing bracket</li>
1.18 cvs 8420: </ul>
8421: </div>
1.1 cvs 8422:
1.18 cvs 8423: <div class="section">
1.37 cvs 8424: <h2><a name="sectb73" id="sectb73">Graphical elements</a></h2>
1.1 cvs 8425:
1.30 cvs 8426: <p>The table below gives the codes for the graphical elements of Thot. These
1.1 cvs 8427: elements can be used in presentation schemas constants and in transcoding
1.37 cvs 8428: rules of translation schemas. Each graphical element is represented by a
1.18 cvs 8429: single character.</p>
8430: <ul>
1.30 cvs 8431: <li>a: a circle</li>
8432: <li><p><tt>A</tt>: an open curve with an arrow head at the end</p>
8433: </li>
8434: <li><tt>b</tt>: a horizontal line along the lower side of the box</li>
8435: <li><tt>B</tt>: an open curve</li>
8436: <li><tt>c</tt>: an ellipse inscribed in the box</li>
8437: <li><tt>C</tt>: a rectangle with rounded corners</li>
8438: <li><tt>D</tt>: an open curve with two arrow heads</li>
8439: <li><tt>e</tt>: The northwest/southeast diagonal of the box with an
8440: arrowhead at the bottom</li>
8441: <li><tt>E</tt>: The southwest/northeast diagonal of the box with an
8442: arrowhead at the top</li>
8443: <li><tt>F</tt>: an open curve with an arrow head at start</li>
8444: <li><tt>g</tt>: a line from the origin of the box to its opposite
8445: corner</li>
8446: <li><tt>h</tt>: a horizontal line as wide as the box and placed in its
8447: middle</li>
8448: <li><tt>l</tt>: a vertical line on the left side of the box</li>
8449: <li><tt>L</tt>: a lozenge</li>
8450: <li><tt>M</tt>: an open broken line with two arrow heads</li>
8451: <li><tt>N</tt>: an open broken line with an arrow head at start</li>
8452: <li><tt>o</tt>: The southwest/northeast diagonal of the box with an
8453: arrowhead at the bottom</li>
8454: <li><tt>O</tt>: The northwest/southeast diagonal of the box with an
8455: arrowhead at the top</li>
8456: <li><tt>p</tt>: a polygon</li>
8457: <li><tt>P</tt>: a rectangle with round corners and a horizontal bar at the
8458: top</li>
8459: <li><tt>Q</tt>: an ellipse with a horizontal bar at the top</li>
8460: <li><tt>r</tt>: a vertical line on the right side of the box</li>
8461: <li><tt>R</tt>: a rectangle which is the shape of the box</li>
8462: <li><tt>s</tt>: a closed curve</li>
8463: <li><tt>S</tt>: an open broken line</li>
8464: <li><tt>t</tt>: a horizontal line along the upper side of the box</li>
8465: <li><tt>U</tt>: an open broken line with an arrow head at the end</li>
8466: <li><tt>v</tt>: a vertical line as tall as the box and placed in its
8467: middle</li>
8468: <li><tt>V</tt>: a down arrow as tall as the box and in its middle</li>
8469: <li>w: a segment (2 points)</li>
8470: <li><tt>W</tt>: the upper right corner</li>
8471: <li>x: a segment (2 points) with an arrow head at the end</li>
8472: <li><tt>X</tt>: the lower right corner</li>
8473: <li>y: a segment (2 points) with an arrow head at the end</li>
8474: <li><tt>Y</tt>: the lower left corner</li>
8475: <li>z: a segment (2 points) with an arrow head at the end</li>
8476: <li><tt>Z</tt>: the upper left corner</li>
8477: <li><tt>space</tt>: a transparent element</li>
8478: <li><tt>^</tt>: an up arrow as tall as the box and in its middle</li>
8479: <li><tt>></tt>: a right arrow as long as the box's width and in its
8480: middle</li>
8481: <li><tt>></tt>: a left arrow as long as the box's width and in its
8482: middle</li>
8483: <li><tt>/</tt>: The southwest/northeast diagonal of the box</li>
8484: <li><tt>\</tt>: the northwest/southeast diagonal of the box</li>
1.18 cvs 8485: </ul>
1.37 cvs 8486: <hr />
1.18 cvs 8487: </div>
8488: </div>
8489: </body>
8490: </html>
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