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1.30 cvs 6: <title>The Languages of Thot</title>
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1.30 cvs 8:
1.18 cvs 9: <body>
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1.19 cvs 11: <div class="frontmatter" align="center">
1.18 cvs 12: <h1>The Languages of Thot</h1>
13:
14: <h3>Vincent Quint</h3>
15:
16: <h4>Translated from French by Ethan Munson</h4>
17:
1.49 ! quint 18: <h4>Version of March 12, 2003</h4>
1.30 cvs 19:
1.47 quint 20: <p>© 1996-2003 INRIA</p>
1.37 cvs 21: <hr />
1.18 cvs 22: </div>
23:
24: <div class="tableofcontents">
25: <h2><a href="languages.toc.html">Contents</a></h2>
26: <ul>
1.40 quint 27: <li><big><a href="#sect2">The document model of Thot</a></big>
1.30 cvs 28: <ul>
29: <li><strong><a href="#sectb21">The logical structure of
30: documents</a></strong></li>
31: <li><strong><a href="#sectb22">Generic and specific
32: structures</a></strong></li>
33: <li><strong><a href="#sectb23">Logical structure and physical
34: structure</a></strong></li>
35: <li><strong><a href="#sectb24">Document structures and object
36: structures</a></strong></li>
37: </ul>
38: </li>
1.40 quint 39: <li><big><a href="#sect3">The S language</a></big>
1.30 cvs 40: <ul>
1.40 quint 41: <li><strong><a href="#sectb31">Document meta-structure</a></strong>
1.30 cvs 42: <ul>
43: <li><a href="#sectc311">The basic types</a></li>
44: <li><a href="#sectc312">Constructed elements</a></li>
1.40 quint 45: <li><a href="#sectc313">Logical structure constructors</a>
1.30 cvs 46: <ul>
47: <li><small><a href="#sectd3131">Aggregate and
48: List</a></small></li>
49: <li><small><a href="#sectd3132">Choice, Schema, and
50: Unit</a></small></li>
51: <li><small><a href="#sectd3133">Reference and
52: Inclusion</a></small></li>
53: <li><small><a href="#sectd3134">Mark pairs</a></small></li>
54: <li><small><a href="#sectd3135">Restrictions and
55: Extensions</a></small></li>
56: <li><small><a href="#sectd3136">Summary</a></small></li>
57: </ul>
58: </li>
59: <li><a href="#sectc315">Attributes</a></li>
60: <li><a href="#sectc316">Discussion of the model</a></li>
61: </ul>
62: </li>
63: <li><strong><a href="#sectb32">The definition language for generic
1.40 quint 64: structures</a></strong>
1.30 cvs 65: <ul>
66: <li><a href="#sectc321">Writing Conventions</a></li>
67: <li><a href="#sectc322">Extension schemas</a></li>
68: <li><a href="#sectc323">The general organization of structure
69: schemas</a></li>
70: <li><a href="#sectc324">The default presentation</a></li>
71: <li><a href="#sectc325">Global Attributes</a></li>
72: <li><a href="#sectc327">Structured elements</a></li>
1.40 quint 73: <li><a href="#sectc328">Structure definitions</a>
1.30 cvs 74: <ul>
75: <li><small><a href="#sectd3281">List</a></small></li>
76: <li><small><a href="#sectd3282">Aggregate</a></small></li>
77: <li><small><a href="#sectd3283">Choice</a></small></li>
78: <li><small><a href="#sectd3284">Reference</a></small></li>
79: <li><small><a href="#sectd3285">Mark pairs</a></small></li>
80: </ul>
81: </li>
82: <li><a href="#sectc329">Imports</a></li>
83: <li><a href="#sectc3210">Extension rules</a></li>
84: <li><a href="#sectc3212">Units</a></li>
85: <li><a href="#sectc3213">Skeleton elements</a></li>
86: <li><a href="#sectc3214">Exceptions</a></li>
87: </ul>
88: </li>
1.40 quint 89: <li><strong><a href="#sectb33">Some examples</a></strong>
1.30 cvs 90: <ul>
91: <li><a href="#sectc331">A class of documents: articles</a></li>
92: <li><a href="#sectc332">A class of objects: mathematical
93: formulas</a></li>
94: </ul>
95: </li>
96: </ul>
97: </li>
1.40 quint 98: <li><big><a href="#sect4">The P language</a></big>
1.30 cvs 99: <ul>
1.40 quint 100: <li><strong><a href="#sectb41">Document presentation</a></strong>
1.30 cvs 101: <ul>
102: <li><a href="#sectc411">Two levels of presentation</a></li>
103: <li><a href="#sectc412">Boxes</a></li>
104: <li><a href="#sectc413">Views and visibility</a></li>
105: <li><a href="#sectc414">Pages</a></li>
106: <li><a href="#sectc415">Numbering</a></li>
1.34 cvs 107: <li><a href="#sectc416">Presentation properties</a></li>
1.30 cvs 108: </ul>
109: </li>
110: <li><strong><a href="#sectb42">Presentation description
1.40 quint 111: language</a></strong>
1.30 cvs 112: <ul>
113: <li><a href="#sectc421">The organization of a presentation
114: schema</a></li>
115: <li><a href="#sectc422">Views</a></li>
116: <li><a href="#sectc423">Print Views</a></li>
117: <li><a href="#sectc424">Counters</a></li>
118: <li><a href="#sectc425">Presentation constants</a></li>
119: <li><a href="#sectc426">Variables</a></li>
120: <li><a href="#sectc427">Default presentation rules</a></li>
121: <li><a href="#sectc428">Presentation and page layout boxes</a></li>
122: <li><a href="#sectc429">Presentation of structured elements</a></li>
123: <li><a href="#sectc4210">Logical attribute presentation</a></li>
124: <li><a href="#sectc4212">Value transmission rules</a></li>
125: <li><a href="#sectc4213">Presentation rules</a></li>
126: <li><a href="#sectc4214">Conditions applying to presentation
1.40 quint 127: rules</a>
1.30 cvs 128: <ul>
1.37 cvs 129: <li><small><a href="#sectd42141">Conditions based on the
130: logical position of the element</a></small></li>
1.42 quint 131: <li><small><a href="#sectd421411">Conditions based on the
132: element type</a></small></li>
1.30 cvs 133: <li><small><a href="#sectd42142">Conditions on
134: references</a></small></li>
135: <li><small><a href="#sectd42143">Conditions on logical
136: attributes</a></small></li>
137: <li><small><a href="#sectd42144">Conditions on page
138: breaks</a></small></li>
139: <li><small><a href="#sectd42145">Conditions on the element's
140: content</a></small></li>
141: <li><small><a href="#sectd42146">Conditions on
142: counters</a></small></li>
143: </ul>
144: </li>
145: <li><a href="#sectc4215">A presentation rule</a></li>
146: <li><a href="#sectc4216">Box axes</a></li>
147: <li><a href="#sectc4217">Distance units</a></li>
148: <li><a href="#sectc4218">Relative positions</a></li>
1.49 ! quint 149: <li><a href="#Floats">Floats</a></li>
1.40 quint 150: <li><a href="#sectc4219">Box extents</a>
1.30 cvs 151: <ul>
152: <li><small><a href="#sectd42191">Fixed extents</a></small></li>
153: <li><small><a href="#sectd42192">Relative
154: extents</a></small></li>
155: <li><small><a href="#sectd42193">Elastic
156: extents</a></small></li>
157: </ul>
158: </li>
159: <li><a href="#sectc4220">Overflow</a></li>
160: <li><a href="#sectc4221">Inheritance</a></li>
1.40 quint 161: <li><a href="#sectc4222">Line breaking</a>
1.30 cvs 162: <ul>
163: <li><small><a href="#sectd42221">Line spacing</a></small></li>
164: <li><small><a href="#sectd42222">First line
165: indentation</a></small></li>
166: <li><small><a href="#sectd42223">Alignment</a></small></li>
167: <li><small><a href="#sectd42225">Hyphenation</a></small></li>
1.40 quint 168: <li><small><a href="#sectd422251">Writing
169: direction</a></small></li>
1.30 cvs 170: <li><small><a href="#sectd42226">Avoiding line
171: breaking</a></small></li>
172: </ul>
173: </li>
174: <li><a href="#sectc4223">Page breaking and line breaking
175: conditions</a></li>
176: <li><a href="#sectc4224">Visibility</a></li>
1.40 quint 177: <li><a href="#sectc4225">Character style properties</a>
1.30 cvs 178: <ul>
179: <li><small><a href="#sectd42251">Character size</a></small></li>
180: <li><small><a href="#sectd42252">Font and character
181: style</a></small></li>
182: <li><small><a href="#sectd42253">Underlining</a></small></li>
183: </ul>
184: </li>
185: <li><a href="#sectc4226">Stacking order</a></li>
186: <li><a href="#sectc4227">Line style</a></li>
187: <li><a href="#sectc4228">Line thickness</a></li>
188: <li><a href="#sectc4229">Fill pattern</a></li>
189: <li><a href="#sectc4230">Colors</a></li>
190: <li><a href="#sectc4230a">Background color and border</a></li>
191: <li><a href="#sectc4230b">Background pictures</a></li>
1.48 quint 192: <li><a href="#sectc4230c">Opacity</a></li>
1.30 cvs 193: <li><a href="#sectc4231">Presentation box content</a></li>
194: <li><a href="#sectc4232">Presentation box creation</a></li>
195: <li><a href="#sectc4233">Page layout</a></li>
196: <li><a href="#sectc4234">Box copies</a></li>
197: </ul>
198: </li>
199: </ul>
200: </li>
1.40 quint 201: <li><big><a href="#sect5">The T language</a></big>
1.30 cvs 202: <ul>
1.40 quint 203: <li><strong><a href="#sectb51">Document translation</a></strong>
1.30 cvs 204: <ul>
205: <li><a href="#sectc511">Translation principles</a></li>
206: <li><a href="#sectc512">Translation procedure</a></li>
207: </ul>
208: </li>
209: <li><strong><a href="#sectb52">Translation definition
1.40 quint 210: language</a></strong>
1.30 cvs 211: <ul>
212: <li><a href="#sectc521">Organization of a translation
213: schema</a></li>
214: <li><a href="#sectc522">Line length</a></li>
215: <li><a href="#sectc523">Buffers</a></li>
216: <li><a href="#sectc524">Counters</a></li>
217: <li><a href="#sectc525">Constants</a></li>
218: <li><a href="#sectc526">Variables</a></li>
219: <li><a href="#sectc527">Translating structure elements</a></li>
1.40 quint 220: <li><a href="#sectc528">Conditional rules</a>
1.30 cvs 221: <ul>
222: <li><small><a href="#sectd5281">Conditions based on the logical
223: position of the element</a></small></li>
224: <li><small><a href="#sectd5282">Conditions on
225: references</a></small></li>
226: <li><small><a href="#sectd5284">Conditions on the
1.41 vatton 227: scripts</a></small></li>
1.30 cvs 228: <li><small><a href="#sectd5285">Conditions on page
229: breaks</a></small></li>
230: <li><small><a href="#sectd5286">Conditions on the element's
231: content</a></small></li>
232: <li><small><a href="#sectd5288">Conditions on the presence of
233: specific presentation rules</a></small></li>
234: <li><small><a href="#sectd5289">Conditions on the presence of
235: logical attributes</a></small></li>
236: <li><small><a href="#sectd52810">Conditions on logical
237: attributes</a></small></li>
238: <li><small><a href="#sectd52811">Conditions on specific
239: presentation rules</a></small></li>
240: </ul>
241: </li>
242: <li><a href="#sectc529">Translation rules</a></li>
243: <li><a href="#sectc5210">The <tt>Create</tt> rule</a></li>
244: <li><a href="#sectc5211">The <tt>Write</tt> rule</a></li>
245: <li><a href="#sectc5212">The <tt>Read</tt> rule</a></li>
246: <li><a href="#sectc5213">The <tt>Include</tt> rule</a></li>
247: <li><a href="#sectc5214">The <tt>Get</tt> rule</a></li>
248: <li><a href="#sectc5215">The <tt>Copy</tt> rule</a></li>
249: <li><a href="#sectc5216">The <tt>Use</tt> rule</a></li>
250: <li><a href="#sectc5217">The <tt>Remove</tt> rule</a></li>
1.31 cvs 251: <li><a href="#sectc5217a">The <code>Ignore</code> rule</a></li>
1.30 cvs 252: <li><a href="#sectc5218">The <tt>NoTranslation</tt> rule</a></li>
253: <li><a href="#sectc5219">The <tt>NoLineBreak</tt> rule</a></li>
254: <li><a href="#sectc5220">The <tt>ChangeMainFile</tt> rule</a></li>
255: <li><a href="#sectc5220a">The <tt>RemoveFile</tt> rule</a></li>
256: <li><a href="#sectc5221">The <tt>Set</tt> and <tt>Add</tt>
257: rules</a></li>
258: <li><a href="#sectc5221a">The <tt>Indent</tt> rule</a></li>
259: <li><a href="#sectc5222">Rule application order</a></li>
260: <li><a href="#sectc5223">Translation of logical attributes</a></li>
261: <li><a href="#sectc5224">Translation of specific
262: presentations</a></li>
263: <li><a href="#sectc5225">Recoding of characters, symbols and
264: graphics</a></li>
265: </ul>
266: </li>
267: </ul>
268: </li>
1.40 quint 269: <li><big><a href="#sect6">Language grammars</a></big>
1.30 cvs 270: <ul>
271: <li><strong><a href="#sectb61">The M meta-language</a></strong></li>
272: <li><strong><a href="#sectb62">The S language</a></strong></li>
273: <li><strong><a href="#sectb63">The P language</a></strong></li>
274: <li><strong><a href="#sectb64">The T language</a></strong></li>
275: </ul>
276: </li>
1.40 quint 277: <li><big><a href="#sect7">Character coding</a></big>
1.30 cvs 278: <ul>
279: <li><strong><a href="#sectb71">Characters</a></strong></li>
280: <li><strong><a href="#sectb72">Symbols</a></strong></li>
281: <li><strong><a href="#sectb73">Graphical elements</a></strong></li>
282: </ul>
283: </li>
1.18 cvs 284: </ul>
1.37 cvs 285: <hr />
1.18 cvs 286: </div>
1.1 cvs 287:
1.18 cvs 288: <div class="chapter">
1.37 cvs 289: <h1><a name="sect2" id="sect2">The document model of Thot</a></h1>
1.1 cvs 290:
1.30 cvs 291: <p>All of the services which Thot provides to the user are based on the
1.37 cvs 292: system's internal document representation. This representation is itself
293: derived from the document model which underlies Thot. The model is presented
1.30 cvs 294: here, prior to the description of the languages which permit the generic
295: specification of documents.</p>
1.1 cvs 296:
1.18 cvs 297: <div class="section">
1.37 cvs 298: <h2><a name="sectb21" id="sectb21">The logical structure of documents</a></h2>
1.1 cvs 299:
1.30 cvs 300: <p>The document model of Thot is primarily designed to allow the user to
301: operate on those entities which s/he has in mind when s/he works on a
302: document. The model makes no assumptions about the nature of these entities.
303: It is essentially these logical entities, such as paragraphs, sections,
304: chapters, notes, titles, and cross-references which give a document its
305: logical structure.</p>
306:
307: <p>Because of this model, the author can divide the document into chapters,
1.37 cvs 308: giving each one a title. The content of these chapters can be further divided
309: into sections, subsections, etc. The text is organized into successive
1.2 cvs 310: paragraphs, according to the content. In the writing phase, the lines, pages,
1.37 cvs 311: margins, spacing, fonts, and character styles are not very important. In
312: fact, if the system requires documents to be written in these terms, it gets
313: in the way. So, Thot's model is primarily based on the logical aspect of
314: documents. The creation of a model of this type essentially requires the
315: definition :</p>
1.18 cvs 316: <ul>
1.30 cvs 317: <li>of the entities which can appear in the documents,</li>
318: <li>and the relations between these entities.</li>
1.18 cvs 319: </ul>
1.30 cvs 320:
1.37 cvs 321: <p>The choice of entities to include in the model can be subtle. Some
322: documents require chapters, while others only need various levels of
323: sections. Certain documents contain appendices, others don't. In different
324: documents the same logical entity may go by different names (e.g.
325: ``Conclusion'' and ``Summary''). Certain entities which are absolutely
326: necessary in some documents, such as clauses in a contract or the address of
327: the recipient in a letter, are useless in most other cases.</p>
1.30 cvs 328:
329: <p>The differences between documents result from more than just the entities
330: that appear in them, but also from the relationships between these entities
1.37 cvs 331: and the ways that they are linked. In certain documents, notes are spread
1.30 cvs 332: throughout the document, for example at the bottom of the page containing the
1.1 cvs 333: cross-reference to them, while in other documents they are collected at the
1.37 cvs 334: end of each chapter or even at the end of the work. As another example, the
1.1 cvs 335: introduction of some documents can contain many sections, while in other
336: documents, the introduction is restricted to be a short sequence of
1.18 cvs 337: paragraphs.</p>
1.30 cvs 338:
1.37 cvs 339: <p>All of this makes it unlikely that a single model can describe any
340: document at a relatively high level. It is obviously tempting to make up a
341: list of widely used entities, such as chapters, sections, paragraphs, and
342: titles, and then map all other entities onto the available choices. In this
343: way, an introduction can be supported as a chapter and a contract clause
344: supported as a paragraph or section. However, in trying to widen the range of
345: usage of certain entities, their meaning can be lost and the power of the
346: model reduced. In addition, while this widening partially solves the problem
347: of choosing entities, it does not solve the problem of their organization:
348: when a chapter must be composed of sections, how does one indicate that an
349: introduction has none when it is merely another chapter? One solution is to
1.1 cvs 350: include introductions in the list of supported entities. But then, how does
351: one distinguish those introductions which are allowed to have sections from
1.37 cvs 352: those which are not. Perhaps this could be done by defining two types of
1.1 cvs 353: introduction. Clearly, this approach risks an infinite expansion of the list
1.18 cvs 354: of widely used entities.</p>
355: </div>
1.1 cvs 356:
1.18 cvs 357: <div class="section">
1.37 cvs 358: <h2><a name="sectb22" id="sectb22">Generic and specific structures</a></h2>
1.1 cvs 359:
1.30 cvs 360: <p>Thus, it is apparently impossible to construct an exhaustive inventory of
361: all those entities which are necessary and sufficient to precisely describe
1.37 cvs 362: any document. It also seems impossible to specify all possible arrangements
363: of these entities in a document. This is why Thot uses a <em>meta-model</em>
1.18 cvs 364: instead, which permits the description of numerous <em>models</em>, each one
365: describing a <em>class</em> of documents.</p>
1.30 cvs 366:
1.37 cvs 367: <p>A <em>class</em> is a set of documents having very similar structure.
368: Thus, the collection of research reports published by a laboratory
369: constitutes a class; the set of commercial proposals by the sales department
370: of a company constitutes another class; the set of articles published by a
371: journal constitutes a third class. Clearly, it is not possible to enumerate
372: every possible document class. It is also clear that new document classes
373: must be created to satisfy new needs and applications.</p>
1.30 cvs 374:
375: <p>To give a more rigorous definition of classes, we must introduce the ideas
1.37 cvs 376: of <em>generic structure</em> and <em>specific structure</em>. Each document
1.30 cvs 377: has a <em>specific structure</em> which organizes the various parts which
1.37 cvs 378: comprise it. We illustrate this with the help of a simple example comparing
1.30 cvs 379: two reports, A and B (<a href="#specstruct">see Figure</a>). The report A
1.37 cvs 380: contains an introduction followed by three chapters and a conclusion. The
381: first chapter contains two sections, the second, three sections. That is the
1.18 cvs 382: <em>specific</em> structure of document A. Similarly, the structure of
1.1 cvs 383: document B is: an introduction, two chapters, a conclusion; Chapter 1 has
1.37 cvs 384: three sections while Chapter 2 has four. The specific structures of these two
1.18 cvs 385: documents are thus different.</p>
1.1 cvs 386:
1.18 cvs 387: <div class="figure">
1.37 cvs 388: <hr />
1.18 cvs 389: <pre> Report A Report B
1.1 cvs 390: Introduction Introduction
391: Chapter 1 Chapter 1
392: Section 1.1 Section 1.1
393: Section 1.2 Section 1.2
394: Chapter 2 Section 1.3
395: Section 2.1 Chapter 2
396: Section 2.2 Section 2.1
397: Section 2.3 Section 2.2
398: Chapter 3 Section 2.3
399: Conclusion Section 2.4
1.18 cvs 400: Conclusion</pre>
1.30 cvs 401:
1.37 cvs 402: <p align="center"><em><a name="specstruct" id="specstruct">Two specific
1.30 cvs 403: structures</a></em></p>
1.37 cvs 404: <hr />
1.30 cvs 405: </div>
406:
407: <p>The <em>generic structure</em> defines the ways in which specific
1.37 cvs 408: structures can be constructed. It specifies how to generate specific
409: structures. The reports A and B, though different, are constructed in
1.30 cvs 410: accordance with the same generic structure, which specifies that a report
411: contains an introduction followed by a variable number of chapters and a
412: conclusion, with each chapter containing a variable number of sections.</p>
413:
414: <p>There is a one-to-one correspondence between a class and a generic
1.37 cvs 415: structure: all the documents of a class are constructed in accordance with
416: the same generic structure. Hence the definition of the class: a class is a
417: set of documents whose specific structure is constructed in accordance with
418: the same generic structure. A class is characterized by its generic
1.30 cvs 419: structure.</p>
1.19 cvs 420:
1.30 cvs 421: <p>Thus, a generic structure can be considered to be a model at the level
1.37 cvs 422: which interests us, but only for one class of documents. When the definition
1.30 cvs 423: is limited to a single class of documents, it is possible to define a model
424: which does a good job of representing the documents of the class, including
1.37 cvs 425: the necessary entities and unencumbered by useless entities. The description
1.30 cvs 426: of the organization of the documents in the class can then be sufficiently
1.18 cvs 427: precise.</p>
428: </div>
1.1 cvs 429:
1.18 cvs 430: <div class="section">
1.37 cvs 431: <h2><a name="sectb23" id="sectb23">Logical structure and physical
432: structure</a></h2>
1.1 cvs 433:
1.30 cvs 434: <p>Generic structures only describe the <em>logical</em> organization of
1.18 cvs 435: documents, not their <em>physical</em> presentation on a screen or on sheets
1.37 cvs 436: of paper. However, for a document to be displayed or printed, its graphic
1.18 cvs 437: presentation must be taken into account.</p>
1.30 cvs 438:
439: <p>An examination of current printed documents shows that the details of
1.1 cvs 440: presentation essentially serve to bring out their logical structure. Outside
441: of some particular domains, notably advertising, the presentation is rarely
1.37 cvs 442: independent of the logical organization of the text. Moreover, the art of
1.1 cvs 443: typography consists of enhancing the organization of the text being set,
1.37 cvs 444: without catching the eye of the reader with overly pronounced effects. Thus,
445: italic and boldface type are used to emphasize words or expressions which
446: have greater significance than the rest of the text: keywords, new ideas,
447: citations, book titles, etc. Other effects highlight the organization of the
1.1 cvs 448: text: vertical space, margin changes, page breaks, centering, eventually
449: combined with the changes in the shapes or weight of the characters. These
450: effects serve to indicate the transitions between paragraphs, sections, or
451: chapters: an object's level in the logical structure of the document is shown
1.18 cvs 452: by the markedness of the effects.</p>
1.30 cvs 453:
454: <p>Since the model permits the description of all of the logical structure of
455: the document, the presentation can be derived from the model without being
1.37 cvs 456: submerged in the document itself. It suffices to use the logical structure of
1.1 cvs 457: the document to make the desired changes in its presentation: changes in type
1.18 cvs 458: size, type style, spacing, margin, centering, etc.</p>
1.30 cvs 459:
460: <p>Just as one cannot define a unique generic logical structure for all
461: document classes, one cannot define universal presentation rules which can be
1.37 cvs 462: applied to all document classes. For certain types of documents the chapter
463: titles will be centered on the page and printed in large, bold type. For
464: other documents, the same chapter titles will be printed in small, italic
465: type and aligned on the left margin.</p>
1.30 cvs 466:
467: <p>Therefore, it is necessary to base the presentation specifications for
1.37 cvs 468: documents on their class. Such a specification can be very fine-grained,
1.1 cvs 469: because the presentation is expressed in terms of the entities defined in the
1.37 cvs 470: generic logical structure of the class. Thus, it is possible to specify a
1.1 cvs 471: different presentation for the chapter titles and the section titles, and
472: similarly to specify titles for the sections according to their level in the
1.37 cvs 473: section hierarchy. The set of rules which specify the presentation of all the
1.18 cvs 474: elements defined in a generic logical structure is called a <em>generic
475: presentation</em>.</p>
1.30 cvs 476:
477: <p>There are several advantages derived from having a presentation linked to
478: the generic structure and described by a generic presentation. Homogeneity is
1.37 cvs 479: the first. Since every document in a class corresponds to the same generic
1.1 cvs 480: logical structure, a homogenous presentation for different documents of the
481: same class can be assured by applying the same generic presentation to all
1.37 cvs 482: documents of the class. Homogeneity of presentation can also be found among
483: the entities of a single document: every section heading will be presented in
484: the same way, the first line of every paragraph of the same type will have
485: the same indentation, etc.</p>
1.30 cvs 486:
487: <p>Another advantage of this approach to presentation is that it facilitates
1.37 cvs 488: changes to the graphical aspect of documents. A change to the generic
489: presentation rules attached to each type of entity will alter the
490: presentation of the entire document, and will do so homogenously. In this
491: case, the internal homogeneity of the class is no longer assured, but the way
492: to control it is simple. It suffices to adopt a single generic presentation
493: for the entire class.</p>
1.30 cvs 494:
495: <p>If the presentation of the class does not have to be homogenous, then the
1.37 cvs 496: appearance of the document can be adapted to the way it will be used or to
497: the device used to render it. This quality is sufficient to allow the
498: existence of <a name="mulpres" id="mulpres">many generic presentations</a>
499: for the same document class. By applying one or the other of these
500: presentations to it, the document can be seen under different graphical
501: aspects. It must be emphasized that this type of modification of the
502: presentation is not a change to the document itself (in its specific logical
503: structure or its content), but only in its appearance at the time of editing
504: or printing.</p>
1.18 cvs 505: </div>
1.1 cvs 506:
1.18 cvs 507: <div class="section">
1.37 cvs 508: <h2><a name="sectb24" id="sectb24">Document structures and object
509: structures</a></h2>
1.1 cvs 510:
1.30 cvs 511: <p>So far, we have only discussed the global structure of documents and have
1.37 cvs 512: not considered the contents found in that structure. We could limit ourselves
1.30 cvs 513: to purely textual contents by assuming that a title or a paragraph contains a
1.37 cvs 514: simple linear text. But this model would be too restrictive. In fact, certain
515: documents contain not only text, but also contain tables, diagrams,
516: photographs, mathematical formulas, and program fragments. The model must
1.18 cvs 517: permit the representation of such <em>objects</em>.</p>
1.30 cvs 518:
519: <p>Just as with the whole of the document, the model takes into account the
1.37 cvs 520: logical structure of objects of this type. Some are clearly structured,
521: others are less so. Logical structure can be recognized in mathematical
522: formulas, in tables, and in certain types of diagrams. On the other hand, it
523: is difficult to define the structure of a photograph or of some drawings. But
1.1 cvs 524: in any case, it does not seem possible to define one unique structure which
1.37 cvs 525: can represent every one of these types of objects. The approach taken in the
1.1 cvs 526: definition of meta-structure and document classes also applies to objects.
527: Object classes can be defined which put together objects of similar type,
1.18 cvs 528: constructed from the same generic logical structure.</p>
1.30 cvs 529:
530: <p>Thus, a mathematical class can be defined and have a generic logical
1.37 cvs 531: structure associated with it. But even if a single generic structure can
1.30 cvs 532: represent a sufficient variety of mathematical formulas, for other objects
1.37 cvs 533: with less rigorous structure, multiple classes must be defined. As for
534: documents, using multiple classes assures that the model can describe the
535: full range of objects to be presented. It also permits the system to support
536: objects which were not initially anticipated. Moreover, this comment applies
1.30 cvs 537: equally to mathematics: different classes of formulas can be described
538: depending on the domain of mathematics being described.</p>
539:
540: <p>Since objects have the same level of logical representation as documents,
1.37 cvs 541: they gain the same advantages. In particular, it is possible to define the
1.1 cvs 542: presentation separately from the objects themselves and attach it to the
1.37 cvs 543: class. Thus, as for documents, objects of the same type have a uniform
1.1 cvs 544: presentation and the presentation of every object in a given class can be
1.37 cvs 545: changed simply by changing the generic presentation of the class. Another
1.1 cvs 546: advantage of using this document model is that the system does not bother the
547: user with the details of presentation, but rather allows the user to
1.18 cvs 548: concentrate on the logical aspect of the document and the objects.</p>
1.30 cvs 549:
550: <p>It is clear that the documents in a class do not necessarily use the same
1.1 cvs 551: classes of objects: one technical report will contain tables while another
552: report will have no tables but will use mathematical formulas. The usable
1.2 cvs 553: object classes are not always mentioned in a limiting way in the generic
1.37 cvs 554: logical structure of documents. Rather, they can be chosen freely from a
1.18 cvs 555: large set, independent of the document class.</p>
1.30 cvs 556:
557: <p>Thus, the object classes will be made commonplace and usable in every
1.1 cvs 558: document. The notion of ``object'' can be enlarged to include not only
559: non-textual elements, but also certain types of textual elements which can
1.37 cvs 560: appear in practically every document, whatever their class. Among these
1.2 cvs 561: textual elements, one can mention enumerations, descriptions, examples,
1.18 cvs 562: quotations, even paragraphs.</p>
1.30 cvs 563:
564: <p>Thus, the document model is not a single, general model describing every
1.37 cvs 565: type of document in one place. Rather, it is a meta-model which can be used
1.30 cvs 566: to describe many different models each of which represents either a class of
1.1 cvs 567: similar documents or a class of similar objects which every document can
1.18 cvs 568: include.</p>
569: </div>
1.37 cvs 570: <hr />
1.18 cvs 571: </div>
1.1 cvs 572:
1.18 cvs 573: <div class="chapter">
1.37 cvs 574: <h1><a name="sect3" id="sect3">The S language</a></h1>
1.1 cvs 575:
1.18 cvs 576: <div class="section">
1.37 cvs 577: <h2><a name="sectb31" id="sectb31">Document meta-structure</a></h2>
1.1 cvs 578:
1.30 cvs 579: <p>Since the concept of meta-structure is well suited to the task of
580: describing documents at a high level of abstraction, this meta-structure must
1.37 cvs 581: be precisely defined. Toward that end this section first presents the basic
1.1 cvs 582: elements from which documents and structured objects are composed and then
1.37 cvs 583: specifies the ways in which these basic elements are assembled into
584: structures representing complete documents and objects.</p>
1.1 cvs 585:
1.18 cvs 586: <div class="subsection">
1.37 cvs 587: <h3><a name="sectc311" id="sectc311">The basic types</a></h3>
1.1 cvs 588:
1.37 cvs 589: <p>At the lowest level of a document's structure, the first atom considered
590: is the character. However, since characters are seldom isolated, usually
1.1 cvs 591: appearing as part of a linear sequence, and in order to reduce the complexity
1.18 cvs 592: of the document structure, <em>character strings</em> are used as atoms and
1.37 cvs 593: consecutive characters belonging to the same structural element are grouped
594: in the same character string.</p>
1.30 cvs 595:
1.37 cvs 596: <p>If the structure of a document is not refined to go down to the level of
597: words or phrases, the contents of a simple paragraph can be considered to be
598: a single character string. On the other hand, the title of a chapter, the
599: title of the first section of that chapter, and the text of the first
600: paragraph of that section constitute three different character strings,
601: because they belong to distinct structural elements.</p>
1.30 cvs 602:
603: <p>If, instead, a very fine-grained representation for the structure of a
1.1 cvs 604: document is sought, character strings could be defined to contain only a
1.37 cvs 605: single word, or even just a single character. This is the case, for example,
606: in programs, for which one wants to retain a structure very close to the
607: syntax of the programming language. In this case, an assignment statement
1.1 cvs 608: initializing a simple variable to zero would be composed of two structural
609: elements, the identifier of the variable (a short character string) and the
1.18 cvs 610: assigned value (a string of a single character, `0').</p>
1.30 cvs 611:
612: <p>The character string is not the only atom necessary for representing those
1.37 cvs 613: documents that interest us. It suffices for purely textual documents, but as
1.1 cvs 614: soon as the non-textual objects which we have considered arise, there must be
615: other atoms; the number of objects which are to be represented determines the
1.18 cvs 616: number of types of atoms that are necessary.</p>
1.30 cvs 617:
618: <p>Primitive <em>graphical elements</em> are used for tables and figures of
1.37 cvs 619: different types. These elements are simple geometric shapes like horizontal
1.1 cvs 620: or vertical lines, which are sufficient for tables, or even oblique lines,
1.2 cvs 621: arrows, rectangles, circles, polygons, and curves for use in figures. From
622: these elements and character strings, graphical objects and tables can be
1.18 cvs 623: constructed.</p>
1.30 cvs 624:
625: <p>Photographs, though having very little structure, must still appear in
1.37 cvs 626: documents. They are supported by <em>picture</em> elements, which are
1.18 cvs 627: represented as matrices of pixels.</p>
1.30 cvs 628:
629: <p>Finally, mathematical notations require certain elements which are
1.37 cvs 630: simultaneously characters and graphical elements, the <em>symbols</em>. By
631: way of example, radicals, integration signs, or even large parentheses are
632: examples of this type of atom. The size of each of these symbols is
1.1 cvs 633: determined by its environment, that is to say, by the expression to which it
1.18 cvs 634: is attached.</p>
1.30 cvs 635:
636: <p>To summarize, the primitive elements which are used in the construction of
1.18 cvs 637: documents and structured objects are:</p>
638: <ul>
1.30 cvs 639: <li>character strings,</li>
640: <li>graphical elements,</li>
641: <li>pictures,</li>
642: <li>and mathematical symbols.</li>
1.18 cvs 643: </ul>
644: </div>
1.1 cvs 645:
1.18 cvs 646: <div class="subsection">
1.37 cvs 647: <h3><a name="sectc312" id="sectc312">Constructed elements</a></h3>
1.30 cvs 648:
1.37 cvs 649: <p>A document is evidently formed from primitive elements. But the model of
650: Thot also proposes higher level elements. Thus, in a document composed of
651: several chapters, each chapter is an element, and in the chapters each
652: section is also an element, and so on. A document is thus an organized set of
1.30 cvs 653: elements.</p>
1.1 cvs 654:
1.37 cvs 655: <p>In a document there are different sorts of elements. Each element has a
656: <em>type</em> which indicates the role of the element within the document as
657: a whole. Thus, we have, for example, the chapter and section types. The
1.1 cvs 658: document is made up of typed elements: elements of the type chapter and
1.37 cvs 659: elements of the type section, among others, but also character string
660: elements and graphical elements: the primitive elements are typed elements
661: just as well. At the other extreme, the document itself is also considered to
662: be a typed element.</p>
1.30 cvs 663:
664: <p>The important difference between the primitive elements and the other
1.37 cvs 665: elements of the document is that the primitive elements are atoms (they
666: cannot be decomposed), whereas the others, called <em>constructed
667: elements</em>, are composed of other elements, which can either be primitive
668: elements or constructed elements. A constructed element of type chapter (or
669: more simply, ``a chapter'') is composed of sections, which are also
670: constructed elements. A paragraph, a constructed element, can be made up of
671: character strings, which are primitive elements, and of equations, which are
672: constructed elements.</p>
1.30 cvs 673:
1.37 cvs 674: <p>A document is also a constructed element. This is an important point. In
1.1 cvs 675: particular, it allows a document to be treated as part of another document,
676: and conversely, permits a part of a document to be treated as a complete
1.37 cvs 677: document. Thus, an article presented in a journal is treated by its author as
1.1 cvs 678: a document in itself, while the editor of the journal considers it to be part
1.37 cvs 679: of an issue. A table or a figure appearing in a document can be extracted and
1.1 cvs 680: treated as a complete document, for example to prepare transparencies for a
1.18 cvs 681: conference.</p>
1.30 cvs 682:
683: <p>These thoughts about types and constructed elements apply just as well to
1.37 cvs 684: objects as they do to documents. A table is a constructed element made up of
685: other constructed elements, rows and columns. A row is formed of cells, which
1.1 cvs 686: are also constructed elements which contain primitive elements (character
1.18 cvs 687: strings) and/or constructed elements like equations.</p>
688: </div>
1.1 cvs 689:
1.18 cvs 690: <div class="subsection">
1.37 cvs 691: <h3><a name="sectc313" id="sectc313">Logical structure constructors</a></h3>
1.1 cvs 692:
1.30 cvs 693: <p>Having defined the primitive elements and the constructed elements, it is
694: now time to define the types of organization which allow the building of
1.37 cvs 695: structures. For this, we rely on the notion of the <em>constructor</em>. A
696: constructor defines a way of assembling certain elements in a structure. It
1.1 cvs 697: resides at the level of the meta-structure: it does not describe the existing
1.37 cvs 698: relations in a given structure, but rather defines how elements are assembled
1.18 cvs 699: to build a structure that conforms to a model.</p>
1.30 cvs 700:
701: <p>In defining the overall organization of documents, the first two
702: constructors considered are the aggregate and the list.</p>
1.1 cvs 703:
1.18 cvs 704: <div class="subsubsection">
1.37 cvs 705: <h4><a name="sectd3131" id="sectd3131">Aggregate and List</a></h4>
1.1 cvs 706:
1.30 cvs 707: <p>The <em>aggregate</em> constructor is used to define constructed element
708: types which are collections of a given number of other elements. These
1.37 cvs 709: collections may or may not be ordered. The elements may be either constructed
710: or primitive and are specified by their type. A report (that is, a
711: constructed element of the report type) has an aggregate structure. It is
1.30 cvs 712: formed from a title, an author's name, an introduction, a body, and a
1.37 cvs 713: conclusion, making it a collection of five element types. This type of
1.30 cvs 714: constructor is found in practically every document, and generally at several
715: levels in a document.</p>
716:
717: <p>The <em>list</em> constructor is used to define constructed elements which
718: are ordered sequences of elements (constructed or primitive) having the same
719: type. The minimum and maximum numbers of elements for the sequence can be
720: specified in the list constructor or the number of elements can be left
721: unconstrained. The body of a report is a list of chapters and is typically
722: required to contain a minimum of two chapters (is a chapter useful if it is
723: the only one in the report?) The chapter itself can contain a list of
1.37 cvs 724: sections, each section containing a list of paragraphs. In the same way as
725: the aggregate, the list is a very frequently used constructor in every type
726: of document. However, these two constructors are not sufficient to describe
727: every document structure; thus other constructors supplement them.</p>
1.18 cvs 728: </div>
1.1 cvs 729:
1.18 cvs 730: <div class="subsubsection">
1.37 cvs 731: <h4><a name="sectd3132" id="sectd3132">Choice, Schema, and Unit</a></h4>
1.1 cvs 732:
1.30 cvs 733: <p>The <em>choice</em> constructor is used to define the structure of an
734: element type for which one alternative is chosen from several possibilities.
1.37 cvs 735: Thus, a paragraph can be either a simple text paragraph, or an enumeration,
736: or a citation.</p>
1.30 cvs 737:
738: <p>The choice constructor indicates the complete list of possible options,
739: which can be too restrictive in certain cases, the paragraph being one such
740: case. Two constructors, <em>unit</em> and <em>schema</em>, address this
1.37 cvs 741: inconvenience. They allow more freedom in the choice of an element type. If a
742: paragraph is defined by a schema constructor, it is possible to put in the
1.1 cvs 743: place of a paragraph a table, an equation, a drawing or any other object
1.37 cvs 744: defined by another generic logical structure. It is also possible to define a
1.1 cvs 745: paragraph as a sequence of units, which could be character strings, symbols,
1.37 cvs 746: or pictures. The choice constructor alone defines a generic logical structure
1.1 cvs 747: that is relatively constrained; in contrast, using units and schemas, a very
1.18 cvs 748: open structure can be defined.</p>
1.30 cvs 749:
750: <p>The <em>schema</em> constructor represents an object defined by a generic
1.18 cvs 751: logical structure chosen freely from among those available.</p>
1.30 cvs 752:
753: <p>The <em>unit</em> constructor represents an element whose type can be
754: either a primitive type or an element type defined as a unit in the generic
755: logical structure of the document, or in another generic logical structure
1.37 cvs 756: used in the document. Such an element may be used in document objects
1.30 cvs 757: constructed according to other generic structures.</p>
758:
759: <p>Thus, for example, if a cross-reference to a footnote is defined in the
1.37 cvs 760: generic logical structure ``Article'' as a unit, a table (an object defined
761: by another generic structure) can contain cross-references to footnotes, when
762: they appear in an article. In another type of document, a table defined by
1.1 cvs 763: the same generic structure can contain other types of elements, depending on
1.37 cvs 764: the type of document into which the table is inserted. All that is needed is
1.1 cvs 765: to declare, in the generic structure for tables, that the contents of cells
1.37 cvs 766: are units. In this way, the generic structure of objects is divided up
767: between different types of documents which are able to adapt themselves to
768: the environment into which they are inserted.</p>
1.18 cvs 769: </div>
1.1 cvs 770:
1.18 cvs 771: <div class="subsubsection">
1.37 cvs 772: <h4><a name="sectd3133" id="sectd3133">Reference and Inclusion</a></h4>
1.1 cvs 773:
1.30 cvs 774: <p>The <em>reference</em> is used to define document elements that are
1.18 cvs 775: cross-references to other elements, such as a section, a chapter, a
1.37 cvs 776: bibliographic citation, or a figure. The reference is bi-directional. It can
1.18 cvs 777: be used to access both the element being cross-referenced and each of the
778: elements which make use of the cross-reference.</p>
1.30 cvs 779:
1.37 cvs 780: <p>References can be either <em>internal</em> or <em>external</em>. That is,
1.1 cvs 781: they can designate elements which appear in the same document or in another
1.18 cvs 782: document.</p>
1.30 cvs 783:
1.37 cvs 784: <p>The <em><a name="inclusion" id="inclusion">inclusion</a></em> constructor
785: is a special type of reference. Like the reference, it is an internal or
786: external bidirectional link, but it is not a cross-reference. This link
787: represents the ``live'' inclusion of the designated element; it accesses the
788: most recent version of that element and not a ``dead'' copy, fixed in the
789: state in which it was found at the moment the copy was made. As soon as an
790: element is modified, all of its inclusions are automatically brought up to
791: date. It must be noted that, in addition to inclusion, Thot permits the
792: creation of ``dead'' copies.</p>
1.30 cvs 793:
794: <p>There are three types of inclusions: inclusions with full expansion,
1.1 cvs 795: inclusions with partial expansion, and inclusions without expansion. During
796: editing, inclusions without expansion are represented on the screen by the
797: name of the included document, in a special color, while inclusions with
1.37 cvs 798: expansion (full or partial) are represented by a copy (full or partial) of
799: the included element (also in a special color). The on-screen representation
800: of a partial inclusion is a <a href="#sectc3213">``skeleton''</a> image of
801: the included document.</p>
1.30 cvs 802:
803: <p>Inclusion with complete expansion can be used to include parts of the same
1.37 cvs 804: document or of other documents. Thus, it can be either an internal or an
805: external link. It can be used to include certain bibliographic entries of a
1.1 cvs 806: scientific article in another article, or to copy part of a mathematical
807: formula into another formula of the same document, thus assuring that both
1.18 cvs 808: copies will remain synchronized.</p>
1.30 cvs 809:
810: <p>Inclusion without expansion or with partial expansion is used to include
1.37 cvs 811: complete documents. It is always an external link. It is used primarily to
1.1 cvs 812: divide very large documents into sub-documents that are easier to manipulate,
1.37 cvs 813: especially when there are many authors. So, a book can include some chapters,
1.1 cvs 814: where each chapter is a different document which can be edited separately.
815: When viewing the book on the screen, it might be desirable to see only the
1.37 cvs 816: titles of the chapters and sections. This can be achieved using inclusion
1.18 cvs 817: with partial expansion.</p>
1.30 cvs 818:
1.37 cvs 819: <p>During printing, inclusions without expansion or with partial expansion
820: can be represented either as they were shown on the screen or by a complete
821: (and up-to-date) copy of the included element or document.</p>
1.30 cvs 822:
823: <p>The inclusion constructor, whatever its type, respects the generic
824: structure: only those elements authorized by the generic structure can be
825: included at a given position in a document.</p>
1.18 cvs 826: </div>
1.1 cvs 827:
1.18 cvs 828: <div class="subsubsection">
1.37 cvs 829: <h4><a name="sectd3134" id="sectd3134">Mark pairs</a></h4>
1.1 cvs 830:
1.30 cvs 831: <p>It is often useful to delimit certain parts of a document independently
1.37 cvs 832: from the logical structure. For example, one might wish to attach some
1.30 cvs 833: information (in the form of an <a href="#sectc315">attribute</a>) or a
834: particular treatment to a group of words or a set of consecutive paragraphs.
835: <em>Mark pairs</em> are used to do this.</p>
836:
837: <p>Mark pairs are elements which are always paired and are terminals in the
1.37 cvs 838: logical structure of the document. Their position in the structure of the
839: document is defined in the generic structure. It is important to note that
1.18 cvs 840: when the terminals of a mark pair are <em>extensions</em> (see the next
841: section), they can be used quite freely.</p>
842: </div>
1.1 cvs 843:
1.18 cvs 844: <div class="subsubsection">
1.37 cvs 845: <h4><a name="sectd3135" id="sectd3135">Restrictions and Extensions</a></h4>
1.1 cvs 846:
1.30 cvs 847: <p>The primitive types and the constructors presented so far permit the
1.1 cvs 848: definition of the logical structure of documents and objects in a rigorous
1.37 cvs 849: way. But this definition can be very cumbersome in certain cases, notably
1.1 cvs 850: when trying to constrain or extend the authorized element types in a
1.37 cvs 851: particular context. <em>Restrictions</em> and <em>extensions</em> are used to
1.18 cvs 852: cope with these cases.</p>
1.30 cvs 853:
854: <p>A restriction associates with a particular element type <em>A</em>, a list
1.37 cvs 855: of those element types which elements of type <em>A</em> may not contain,
856: even if the definition of type <em>A</em> and those of its components
857: authorize them otherwise. This simplifies the writing of generic logical
858: structures and allows limitations to be placed, when necessary, on the
859: choices offered by the schema and unit constructors.</p>
860:
861: <p>Extensions are the inverse of restrictions. They identify a list of
862: element types whose presence <em>is</em> permitted, even if its definition
863: and those of its components do not authorize them otherwise.</p>
1.18 cvs 864: </div>
865:
866: <div class="subsubsection">
1.37 cvs 867: <h4><a name="sectd3136" id="sectd3136">Summary</a></h4>
1.18 cvs 868:
1.30 cvs 869: <p>Thus, four constructors are used to construct a document:</p>
1.18 cvs 870: <ul>
1.30 cvs 871: <li>the aggregate constructor (ordered or not),</li>
872: <li>the list constructor,</li>
873: <li>the choice constructor and its extensions, the unit and schema
874: constructors,</li>
875: <li>the reference constructor and its variant, the inclusion.</li>
876: </ul>
877:
1.37 cvs 878: <p>These constructors are also sufficient for objects. Thus, these
1.30 cvs 879: constructors provide a homogenous meta-model which can describe both the
880: organization of the document as a whole and that of the various types of
1.37 cvs 881: objects which it contains. After presenting the description language for
1.30 cvs 882: generic structures, we will present several examples which illustrate the
883: appropriateness of the model.</p>
884:
1.37 cvs 885: <p>The first three constructors (aggregate, list and choice) lead to
886: tree-like structures for documents and objects, the objects being simply the
887: subtrees of the tree of a document (or even of other objects' subtrees). The
888: reference constructor introduces other, non-hierarchical, relations which
889: augment those of the tree: when a paragraph makes reference to a chapter or a
890: section, that relation leaves the purely tree-like structure. Moreover,
891: external reference and inclusion constructors permit the establishment of
892: links between different documents, thus creating a hypertext structure.</p>
1.18 cvs 893: </div>
894: </div>
1.1 cvs 895:
1.18 cvs 896: <div class="subsection">
1.37 cvs 897: <h3><a name="sectc315" id="sectc315">Attributes</a></h3>
1.1 cvs 898:
1.30 cvs 899: <p>There remain logical aspects of documents that are not entirely described
1.37 cvs 900: by the structure. Certain types of semantic information, which are not stated
901: explicitly in the text, must also be taken into account. In particular, such
1.1 cvs 902: information is shown by typographic effects which do not correspond to a
1.37 cvs 903: change between structural elements. In fact, certain titles are set in bold
1.1 cvs 904: or italic or are printed in a different typeface from the rest of the text in
1.37 cvs 905: order to mark them as structurally distinct. But these same effects
1.1 cvs 906: frequently appear in the middle of continuous text (e.g. in the interior of a
1.37 cvs 907: paragraph). In this case, there is no change between structural elements; the
908: effect serves to highlight a word, expression, or phrase. The notion of an
1.18 cvs 909: <em>attribute</em> is used to express this type of information.</p>
1.30 cvs 910:
911: <p>An attribute is a piece of information attached to a structural element
912: which augments the type of the element and clarifies its function in the
913: document. Keywords, foreign language words, and titles of other works can all
1.37 cvs 914: be represented by character strings with attached attributes. Attributes may
915: also be attached to constructed elements. Thus, an attribute indicating the
1.1 cvs 916: language can be attached to a single word or to a large part of a
1.18 cvs 917: document.</p>
1.30 cvs 918:
919: <p>In fact, an attribute can be any piece of information which is linked to a
1.37 cvs 920: part of a document and which can be used by agents which work on the
921: document. For example, the language in which the document is written
922: determines the set of characters used by an editor or formatter. It also
923: determines the algorithm or hyphenation dictionary to be used. The attribute
924: ``keyword'' facilitates the work of an information retrieval system. The
925: attribute ``index word'' allows a formatter to automatically construct an
926: index at the end of the document.</p>
1.30 cvs 927:
928: <p>As with the types of constructed elements, the attributes and the values
1.37 cvs 929: they can take are defined separately in each generic logical structure, not
930: in the meta-model, according to the needs of the document class or the nature
931: of the object.</p>
1.30 cvs 932:
933: <p>Many types of attributes are offered: numeric, textual, references, and
1.18 cvs 934: enumerations:</p>
935: <ul>
1.40 quint 936: <li><em>Numeric attributes</em> can take integer values (negative,
937: positive, or null).</li>
938: <li><em>Textual attributes</em> have as their values character strings.</li>
939: <li><em>Reference attributes</em> designate an element of the logical
940: structure.</li>
941: <li><em>Enumeration attributes</em> can take one value from a limited list
942: of possible values, each value being a name.</li>
1.18 cvs 943: </ul>
1.30 cvs 944:
945: <p>In a generic structure, there is a distinction between <em>global
1.37 cvs 946: attributes</em> and <em>local attributes</em>. A global attribute can be
1.1 cvs 947: applied to every element type defined in the generic structure where it is
1.37 cvs 948: specified. In contrast, a local attribute can only be applied to certain
949: types of elements, even only a single type. The ``language'' attribute
950: presented above is an example of a global attribute. An example of a local
1.1 cvs 951: attribute is the rank of an author (principal author of the document or
952: secondary author): this attribute can only be applied sensibly to an element
1.18 cvs 953: of the ``author'' type.</p>
1.30 cvs 954:
955: <p>Attributes can be assigned to the elements which make up the document in
1.37 cvs 956: many different ways. The author can freely and dynamically place them on any
1.30 cvs 957: part of the document in order to attach supplementary information of his/her
1.18 cvs 958: choice. However, attributes may only be assigned in accordance with the rules
1.37 cvs 959: of the generic structure; in particular, local attributes can only be
960: assigned to those element types for which they are defined.</p>
1.30 cvs 961:
962: <p>In the generic structure, certain local attributes can be made mandatory
1.37 cvs 963: for certain element types. In this case, Thot automatically associates the
964: attribute with the elements of this type and it requires the user to provide
965: a value for this attribute.</p>
966:
967: <p>Attributes can also be automatically assigned, with a given value, by
968: every application processing the document in order to systematically add a
969: piece of information to certain predefined elements of the document. By way
970: of example, in a report containing a French abstract and an English abstract,
971: each of the two abstracts is defined as a sequence of paragraphs. The first
1.1 cvs 972: abstract has a value of ``French'' for the ``language'' attribute while the
1.18 cvs 973: second abstract's ``language'' attribute has a value of ``English''.</p>
1.30 cvs 974:
975: <p>In the case of mark pairs, attributes are logically associated with the
976: pair as a whole, but are actually attached to the first mark.</p>
1.18 cvs 977: </div>
1.1 cvs 978:
1.18 cvs 979: <div class="subsection">
1.37 cvs 980: <h3><a name="sectc316" id="sectc316">Discussion of the model</a></h3>
1.1 cvs 981:
1.37 cvs 982: <p>The notions of attribute, constructor, and structured element are used in
983: the definition of generic logical structures of documents and objects. The
984: problem is to assemble them to form generic structures. In fact, many types
985: of elements and attributes can be found in a variety of generic structures.
986: Rather than redefine them for each structure in which they appear, it is best
987: to share them between structures. The object classes already fill this
988: sharing function. If a mathematical class is defined, its formulas can be
989: used in many different document classes, without redefining the structure of
990: each class. This problem arises not only for the objects considered here; it
991: also arises for the commonplace textual elements found in many document
992: classes. This is the reason why the notion of object is so broad and why
993: paragraphs and enumerations are also considered to be objects. These object
994: classes not only permit the sharing of the structures of elements, but also
995: of the attributes defined in the generic structures.</p>
1.30 cvs 996:
997: <p>Structure, such as that presented here, can appear very rigid, and it is
1.1 cvs 998: possible to imagine that a document editing system based on this model could
1.37 cvs 999: prove very constraining to the user. This is, in fact, a common criticism of
1000: syntax-directed editors. This defect can be avoided with Thot, primarily for
1.18 cvs 1001: three reasons:</p>
1002: <ul>
1.30 cvs 1003: <li>the generic structures are not fixed in the model itself,</li>
1004: <li>the model takes the dynamics of documents into account,</li>
1005: <li>the constructors offer great flexibility.</li>
1.18 cvs 1006: </ul>
1.30 cvs 1007:
1008: <p>When the generic structure of a document is not predefined, but rather is
1.1 cvs 1009: constructed specifically for each document class, it can be carefully adapted
1.37 cvs 1010: to the current needs. In cases where the generic structure is inadequate for
1.1 cvs 1011: a particular document of the class, it is always possible either to create a
1012: new class with a generic structure well suited to the new case or to extend
1.37 cvs 1013: the generic structure of the existing class to take into account the
1014: specifics of the document which poses the problem. These two solutions can
1015: also be applied to objects whose structures prove to be poorly designed.</p>
1.30 cvs 1016:
1017: <p>The model is sufficiently flexible to take into account all the phases of
1.37 cvs 1018: the life of the document. When a generic structure specifies that a report
1019: must contain a title, an abstract, an introduction, at least two chapters,
1020: and a conclusion, this means only that a report, <em>upon completion</em>,
1021: will have to contain all of these elements. When the author begins writing,
1022: none of these elements is present. Thot uses this model. Therefore, it
1023: tolerates documents which do not conform strictly to the generic structure of
1024: their class; it also considers the generic logical structure to be a way of
1025: helping the user in the construction of a complex document.</p>
1.30 cvs 1026:
1027: <p>In contrast, other applications may reject a document which does not
1.37 cvs 1028: conform strictly to its generic structure. This is, for example, what is done
1.30 cvs 1029: by compilers which refuse to generate code for a program which is not
1.37 cvs 1030: syntactically correct. This might also occur when using a document
1.18 cvs 1031: application for a report which does not have an abstract or title.</p>
1.30 cvs 1032:
1033: <p>The constructors of the document model bring a great flexibility to the
1.37 cvs 1034: generic structures. A choice constructor (and even more, a unit or schema
1035: constructor) can represent several, very different elements. The list
1036: constructor permits the addition of more elements of the same type. Used
1.1 cvs 1037: together, these two constructors permit any series of elements of different
1.37 cvs 1038: types. Of course, this flexibility can be reduced wherever necessary since a
1.1 cvs 1039: generic structure can limit the choices or the number of elements in a
1.18 cvs 1040: list.</p>
1.30 cvs 1041:
1042: <p>Another difficulty linked to the use of structure in the document model
1.37 cvs 1043: resides in the choice of the level of the structure. The structure of a
1.1 cvs 1044: discussion could be extracted from the text itself via linguistic analysis.
1045: Some studies are exploring this approach, but the model of Thot excludes this
1.37 cvs 1046: type of structure. It only takes into account the logical structure provided
1.18 cvs 1047: explicitly by the author.</p>
1.30 cvs 1048:
1.37 cvs 1049: <p>However, the level of structure of the model is not imposed. Each generic
1050: structure defines its own level of structure, adapted to the document class
1051: or object and to the ways in which it will be processed. If it will only be
1052: edited and printed, a relatively simple structure suffices. If more
1053: specialized processing will be applied to it, the structure must represent
1054: the element types on which this processing must act. By way of example, a
1055: simple structure is sufficient for printing formulas, but a more complex
1056: structure is required to perform symbolic or numeric calculations on the
1057: mathematical expressions. The document model of Thot allows both types of
1058: structure.</p>
1.18 cvs 1059: </div>
1060: </div>
1.1 cvs 1061:
1.18 cvs 1062: <div class="section">
1.37 cvs 1063: <h2><a name="sectb32" id="sectb32">The definition language for generic
1064: structures</a></h2>
1.1 cvs 1065:
1.37 cvs 1066: <p>Generic structures, which form the basis of the document model of Thot,
1067: are specified using a special language. This definition language, called S,
1068: is described in this section.</p>
1.30 cvs 1069:
1070: <p>Each generic structure, which defines a class of documents or objects, is
1.2 cvs 1071: specified by a file, written in the S language, which is called a
1.37 cvs 1072: <em>structure schema</em>. Structure schemas are compiled into tables, called
1.18 cvs 1073: structure tables, which are used by Thot and which determine its behavior.</p>
1.1 cvs 1074:
1.18 cvs 1075: <div class="subsection">
1.37 cvs 1076: <h3><a name="sectc321" id="sectc321">Writing Conventions</a></h3>
1.1 cvs 1077:
1.30 cvs 1078: <p>The grammar of S, like those of the languages P and T presented later, is
1.1 cvs 1079: described using the meta-language M, derived from the Backus-Naur Form
1.18 cvs 1080: (BNF).</p>
1.30 cvs 1081:
1082: <p>In this meta-language each rule of the grammar is composed of a grammar
1.37 cvs 1083: symbol followed by an equals sign (`=') and the right part of the rule. The
1.30 cvs 1084: equals sign plays the same role as the traditional `::=' of BNF: it indicates
1.37 cvs 1085: that the right part defines the symbol of the left part. In the right
1.30 cvs 1086: part,</p>
1.18 cvs 1087: <dl>
1.30 cvs 1088: <dt>concatenation</dt>
1089: <dd>is shown by the juxtaposition of symbols;</dd>
1090: <dt>character strings</dt>
1.37 cvs 1091: <dd>between apostrophes ' represent terminal symbols, that is, keywords
1092: in the language defined. Keywords are written here in upper-case
1093: letters, but can be written in any combination of upper and lower-case
1094: letters. For example, the keyword <tt>DEFPRES</tt> of S can also be
1095: written as <tt>defpres</tt> or <tt>DefPres</tt>.</dd>
1.30 cvs 1096: <dt>material between brackets</dt>
1097: <dd>(`[' and `]') is optional;</dd>
1098: <dt>material between angle brackets</dt>
1099: <dd>(`<' and `>') can be repeated many times or omitted;</dd>
1100: <dt>the slash</dt>
1.37 cvs 1101: <dd>(`/') indicates an alternative, a choice between the options
1102: separated by the slash character;</dd>
1.30 cvs 1103: <dt>the period</dt>
1104: <dd>marks the end of a rule;</dd>
1105: <dt>text between braces</dt>
1106: <dd>(`{' and `}') is simply a comment.</dd>
1.18 cvs 1107: </dl>
1.30 cvs 1108:
1109: <p>The M meta-language also uses the concepts of identifiers, strings, and
1.18 cvs 1110: integers:</p>
1111: <dl>
1.30 cvs 1112: <dt><tt>NAME</tt></dt>
1.37 cvs 1113: <dd>represents an identifier, a sequence of letters (upper or
1114: lower-case), digits, and underline characters (`_'), beginning with a
1115: letter. Also considered a letter is the sequence of characters
1116: `<tt>\nnn</tt>' where the letter <tt>n</tt> represents the ISO Latin-1
1117: code of the letter in octal. It is thus possible to use accented
1118: letters in identifiers. The maximum length of identifiers is fixed by
1119: the compiler. It is normally 31 characters.
1.30 cvs 1120: <p>Unlike keywords, upper and lower-case letters are distinct in
1121: identifiers. Thus, <tt>Title</tt>, <tt>TITLE</tt>, and <tt>title</tt>
1122: are considered different identifiers.</p>
1123: </dd>
1124: <dt><tt>STRING</tt></dt>
1.37 cvs 1125: <dd>represents a string. This is a string of characters delimited by
1126: apostrophes. If an apostrophe must appear in a string, it is doubled.
1127: As with identifiers, strings can contain characters represented by
1128: their octal code (after a backslash). As with apostrophes, if a
1129: backslash must appear in a string, it is doubled.</dd>
1.30 cvs 1130: <dt><tt>NUMBER</tt></dt>
1131: <dd>represents a positive integer or zero (without a sign), or said
1132: another way, a sequence of decimal digits.</dd>
1.18 cvs 1133: </dl>
1.30 cvs 1134:
1135: <p>The M language can be used to define itself as follows:</p>
1.18 cvs 1136: <pre>{ Any text between braces is a comment. }
1.30 cvs 1137: Grammar = Rule < Rule > 'END' .
1138: { The < and > signs indicate zero }
1.1 cvs 1139: { or more repetitions. }
1140: { END marks the end of the grammar. }
1141: Rule = Ident '=' RightPart '.' .
1142: { The period indicates the end of a rule }
1143: RightPart = RtTerminal / RtIntermed .
1144: { The slash indicates a choice }
1145: RtTerminal ='NAME' / 'STRING' / 'NUMBER' .
1146: { Right part of a terminal rule }
1.30 cvs 1147: RtIntermed = Possibility < '/' Possibility > .
1.1 cvs 1148: { Right part of an intermediate rule }
1.30 cvs 1149: Possibility = ElemOpt < ElemOpt > .
1150: ElemOpt = Element / '[' Element < Element > ']' /
1151: '<' Element < Element > '>' .
1.1 cvs 1152: { Brackets delimit optional parts }
1153: Element = Ident / KeyWord .
1154: Ident = NAME .
1155: { Identifier, sequence of characters }
1156: KeyWord = STRING .
1157: { Character string delimited by apostrophes }
1.18 cvs 1158: END</pre>
1159: </div>
1.1 cvs 1160:
1.18 cvs 1161: <div class="subsection">
1.37 cvs 1162: <h3><a name="sectc322" id="sectc322">Extension schemas</a></h3>
1.1 cvs 1163:
1.30 cvs 1164: <p>A structure schema defines the generic logical structure of a class of
1.1 cvs 1165: documents or objects, independent of the operations which can be performed on
1.37 cvs 1166: the documents. However, certain applications may require particular
1.1 cvs 1167: information to be represented by the structure for the documents that they
1.37 cvs 1168: operate on. Thus a document version manager will need to indicate in the
1169: document the parts which belong to one version or another. An indexing system
1.1 cvs 1170: will add highly-structured index tables as well as the links between these
1.18 cvs 1171: tables and the rest of the document.</p>
1.30 cvs 1172:
1173: <p>Thus, many applications need to extend the generic structure of the
1.37 cvs 1174: documents on which they operate to introduce new attributes or element types.
1175: These additions are specific to each application and must be able to be
1176: applied to any generic structure: users will want to manage versions or
1177: construct indices for many types of documents. Extension schemas fulfill this
1178: role: they define attributes, elements, units, etc., but they can only be
1179: used jointly with a structure schema that they complete. Otherwise, structure
1180: schemas can always be used without these extensions when the corresponding
1181: applications are not available.</p>
1.18 cvs 1182: </div>
1.1 cvs 1183:
1.18 cvs 1184: <div class="subsection">
1.37 cvs 1185: <h3><a name="sectc323" id="sectc323">The general organization of structure
1186: schemas</a></h3>
1.1 cvs 1187:
1.30 cvs 1188: <p>Every structure schema begins with the keyword <tt>STRUCTURE</tt> and ends
1.37 cvs 1189: with the keyword <tt>END</tt>. The keyword <tt>STRUCTURE</tt> is followed by
1.18 cvs 1190: the keyword <tt>EXTENSION</tt> in the case where the schema defines an
1.1 cvs 1191: extension, then by the name of the generic structure which the schema defines
1.37 cvs 1192: (the name of the document or object class). The name of the structure is
1.18 cvs 1193: followed by a semicolon.</p>
1.30 cvs 1194:
1195: <p>In the case of a complete schema (that is, a schema which is not an
1.1 cvs 1196: extension), the definition of the name of the structure is followed by the
1197: declarations of the default presentation schema, the global attributes, the
1.37 cvs 1198: structure rules, the units, the skeleton elements and the exceptions. Only
1199: the definition of the structure rules is required. Each series of
1200: declarations begins with a keyword: <tt>DEFPRES</tt>, <tt>ATTR</tt>,
1201: <tt>STRUCT</tt>, <tt>UNITS</tt>, <tt>EXPORT</tt>, <tt>EXCEPT</tt>.</p>
1.34 cvs 1202:
1203: <p>In the case of an extension schema, there are no skeleton elements and the
1204: <tt>STRUCT</tt> section is optional, while that section is required in a
1.37 cvs 1205: schema that is not an extension. On the other hand, extension schemas can
1206: contain an <tt>EXTENS</tt> section, which must not appear in a schema which
1207: is not an extension; this section defines the complements to attach to the
1208: rules found in the schema to which the extension will be added. The sections
1209: <tt>ATTR</tt>, <tt>STRUCT</tt>, and <tt>UNITS</tt> define new attributes, new
1210: elements, and new units which add their definitions to the principal
1211: schema.</p>
1.18 cvs 1212: <pre> StructSchema ='STRUCTURE' ElemID ';'
1.1 cvs 1213: 'DEFPRES' PresID ';'
1214: [ 'ATTR' AttrSeq ]
1215: 'STRUCT' RulesSeq
1216: [ 'UNITS' RulesSeq ]
1217: [ 'EXPORT' SkeletonSeq ]
1218: [ 'EXCEPT' ExceptSeq ]
1219: 'END' .
1.18 cvs 1220: ElemID = NAME .</pre>
1.30 cvs 1221:
1222: <p>or</p>
1.18 cvs 1223: <pre> ExtensSchema ='STRUCTURE' 'EXTENSION' ElemID ';'
1.1 cvs 1224: 'DEFPRES' PresID ';'
1225: [ 'ATTR' AttrSeq ]
1226: [ 'STRUCT' RulesSeq ]
1227: [ 'EXTENS' ExtensRuleSeq ]
1228: [ 'UNITS' RulesSeq ]
1229: [ 'EXCEPT' ExceptSeq ]
1230: 'END' .
1.18 cvs 1231: ElemID = NAME .</pre>
1232: </div>
1.1 cvs 1233:
1.18 cvs 1234: <div class="subsection">
1.37 cvs 1235: <h3><a name="sectc324" id="sectc324">The default presentation</a></h3>
1.1 cvs 1236:
1.37 cvs 1237: <p>It was shown <a href="#mulpres">above</a> that many different
1238: presentations are possible for documents and objects of the same class. The
1239: structure schema defines a preferred presentation for the class, called the
1240: <em>default presentation</em>. Like generic structures, presentations are
1241: described by programs, called <em>presentation schemas</em>, which are
1242: written in a specific language, P, presented <a href="#sectb42">later</a> in
1243: this document. The name appearing after the keyword <tt>DEFPRES</tt> is the
1244: name of the default presentation schema. When a new document is created, Thot
1245: will use this presentation schema by default, but the user remains free to
1246: choose another if s/he wishes.</p>
1.18 cvs 1247: <pre> PresID = NAME .</pre>
1248: </div>
1.1 cvs 1249:
1.18 cvs 1250: <div class="subsection">
1.37 cvs 1251: <h3><a name="sectc325" id="sectc325">Global Attributes</a></h3>
1.1 cvs 1252:
1.30 cvs 1253: <p>If the generic structure includes global attributes of its own, they are
1.37 cvs 1254: declared after the keyword <tt>ATTR</tt>. Each global attribute is defined by
1255: its name, followed by an equals sign and the definition of its type. The
1.18 cvs 1256: declaration of a global attribute is terminated by a semi-colon.</p>
1.30 cvs 1257:
1258: <p>For attributes of the numeric, textual, or reference types, the type is
1.37 cvs 1259: indicated by a keyword, <tt>INTEGER</tt>, <tt>TEXT</tt>, or
1260: <tt>REFERENCE</tt> respectively.</p>
1.30 cvs 1261:
1262: <p>In the case of a reference attribute, the keyword <tt>REFERENCE</tt> is
1.37 cvs 1263: followed by the type of the referenced element in parentheses. It can refer
1.18 cvs 1264: to any type at all, specified by using the keyword <tt>ANY</tt>, or to a
1.37 cvs 1265: specific type. In the latter case, the element type designated by the
1.18 cvs 1266: reference can be defined either in the <a href="#sectc327"><tt>STRUCT</tt>
1267: section</a> of the same structure schema or in the <tt>STRUCT</tt> section of
1.37 cvs 1268: another structure schema. When the type is defined in another schema, the
1.1 cvs 1269: element type is followed by the name of the structure schema (within
1.37 cvs 1270: parentheses) in which it is defined. The name of the designated element type
1.18 cvs 1271: can be preceded by the keyword <tt>First</tt> or <tt>Second</tt>, but only in
1.37 cvs 1272: the case where the type is defined as <a href="#sectd3285">a pair</a>. These
1.1 cvs 1273: keywords indicate whether the attribute must designate the first mark of the
1.37 cvs 1274: pair or the second. If the reference refers to a pair and neither of these
1.18 cvs 1275: two keywords is present, then the first mark is used.</p>
1.30 cvs 1276:
1.37 cvs 1277: <p>In the case of an enumeration attribute, the equals sign is followed by
1278: the list of names representing the possible values of the attribute, the
1279: names being separated from each other by commas. An enumeration attribute has
1280: at least one possible value; the maximum number of values is defined by the
1.18 cvs 1281: compiler for the S language.</p>
1.30 cvs 1282: <pre> AttrSeq = Attribute < Attribute > .
1.1 cvs 1283: Attribute = AttrID '=' AttrType ';' .
1284: AttrType = 'INTEGER' / 'TEXT' /
1285: 'REFERENCE' '(' RefType ')' /
1286: ValueSeq .
1287: RefType = 'ANY' / [ FirstSec ] ElemID [ ExtStruct ] .
1288: FirstSec = 'First' / 'Second' .
1289: ExtStruct = '(' ElemID ')' .
1.30 cvs 1290: ValueSeq = AttrVal < ',' AttrVal > .
1.1 cvs 1291: AttrID = NAME .
1.18 cvs 1292: AttrVal = NAME .</pre>
1.30 cvs 1293:
1294: <p>There is a predefined global text attribute, the <em>language</em>, which
1.37 cvs 1295: is automatically added to every Thot structure schema. This attribute allows
1296: Thot to perform certain actions, such as hyphenation and spell-checking,
1297: which cannot be performed without knowing the language in which each part of
1298: the document is written. This attribute can be used just like any explicitly
1.18 cvs 1299: declared attribute: the system acts as if every structure schema contains</p>
1300: <pre>ATTR
1301: Language = TEXT;</pre>
1.30 cvs 1302:
1.18 cvs 1303: <blockquote class="example">
1.30 cvs 1304: <p><strong>Example:</strong></p>
1305:
1306: <p>The following specification defines the global enumeration attribute
1307: WordType.</p>
1308: <pre>ATTR
1.18 cvs 1309: WordType = Definition, IndexWord, DocumentTitle;</pre>
1310: </blockquote>
1311: </div>
1.1 cvs 1312:
1.18 cvs 1313: <div class="subsection">
1.37 cvs 1314: <h3><a name="sectc327" id="sectc327">Structured elements</a></h3>
1.1 cvs 1315:
1.30 cvs 1316: <p>The rules for defining structured elements are required, except in an
1.1 cvs 1317: extension schema: they constitute the core of a structure schema, since they
1318: define the structure of the different types of elements that occur in a
1.18 cvs 1319: document or object of the class defined by the schema.</p>
1.30 cvs 1320:
1321: <p>The first structure rule after the keyword <tt>STRUCT</tt> must define the
1.1 cvs 1322: structure of the class whose name appears in the first instruction
1.37 cvs 1323: (<tt>STRUCTURE</tt>) of the schema. This is the root rule of the schema,
1.18 cvs 1324: defining the root of the document tree or object tree.</p>
1.30 cvs 1325:
1326: <p>The remaining rules may be placed in any order, since the language permits
1.37 cvs 1327: the definition of element types before or after their use, or even in the
1328: same instruction in which they are used. This last case allows the definition
1329: of recursive structures.</p>
1.30 cvs 1330:
1331: <p>Each rule is composed of a name (the name of the element type whose
1332: structure is being defined) followed by an equals sign and a structure
1333: definition.</p>
1334:
1.37 cvs 1335: <p>If any local attributes are associated with the element type defined by
1336: the rule, they appear between parentheses after the type name and before the
1337: equals sign. The parentheses contain, first, the keyword <tt>ATTR</tt>, then
1338: the list of local attributes, separated by commas. Each local attribute is
1.2 cvs 1339: composed of the name of the attribute followed by an equals sign and the
1.18 cvs 1340: definition of the attribute's type, just as in the definition of <a
1.37 cvs 1341: href="#sectc325">global attributes</a>. The name of the attribute can be
1342: preceded by an exclamation point to indicate that the attribute must always
1343: be present for this element type. The same attribute, identified by its name,
1344: can be defined as a local attribute for multiple element types. In this case,
1345: the equals sign and definition of the attribute type need only appear in the
1346: first occurrence of the attribute. It should be noted that global attributes
1347: cannot also be defined as local attributes.</p>
1.30 cvs 1348:
1349: <p>If any <a href="#sectd3135">extensions</a> are defined for this element
1350: type, a plus sign follows the structure definition and the names of the
1.37 cvs 1351: extension element types appear between parentheses after the plus. If there
1352: are multiple extensions, they are separated by commas. These types can either
1.30 cvs 1353: be defined in the same schema, defined in other schemas, or they may be base
1.18 cvs 1354: types identified by the keywords <tt>TEXT</tt>, <tt>GRAPHICS</tt>,
1355: <tt>SYMBOL</tt>, or <tt>PICTURE</tt>.</p>
1.30 cvs 1356:
1357: <p><a href="#sectd3135">Restrictions</a> are indicated in the same manner as
1.18 cvs 1358: extensions, but they are introduced by a minus sign and they come after the
1359: extensions, or if there are no extensions, after the structure definition.</p>
1.30 cvs 1360:
1.37 cvs 1361: <p>If the values of attributes must be attached systematically to this
1362: element type, they are introduced by the keyword <tt>WITH</tt> and declared
1363: in the form of a list of fixed-value attributes. When such definitions of
1364: fixed attribute values appear, they are always the last part of the rule.</p>
1.30 cvs 1365:
1366: <p>The rule is terminated by a semicolon.</p>
1367: <pre> RuleSeq = Rule < Rule > .
1.1 cvs 1368: Rule = ElemID [ LocAttrSeq ] '=' DefWithAttr ';'.
1.30 cvs 1369: LocAttrSeq = '(' 'ATTR' LocAttr < ';' LocAttr > ')' .
1.1 cvs 1370: LocAttr = [ '!' ] AttrID [ '=' AttrType ] .
1371: DefWithAttr = Definition
1372: [ '+' '(' ExtensionSeq ')' ]
1373: [ '-' '(' RestrictSeq ')' ]
1374: [ 'WITH' FixedAttrSeq ] .
1.30 cvs 1375: ExtensionSeq = ExtensionElem < ',' ExtensionElem > .
1.1 cvs 1376: ExtensionElem = ElemID / 'TEXT' / 'GRAPHICS' /
1377: 'SYMBOL' / 'PICTURE' .
1.30 cvs 1378: RestrictSeq = RestrictElem < ',' RestrictElem > .
1.1 cvs 1379: RestrictElem = ElemID / 'TEXT' / 'GRAPHICS' /
1.18 cvs 1380: 'SYMBOL' / 'PICTURE' .</pre>
1.30 cvs 1381:
1382: <p>The list of fixed-value attributes is composed of a sequence of
1.37 cvs 1383: attribute-value pairs separated by commas. Each pair contains the name of the
1.1 cvs 1384: attribute and the fixed value for this element type, the two being separated
1.37 cvs 1385: by an equals sign. If the sign is preceded by a question mark the given value
1.1 cvs 1386: is only an initial value that may be modified later rather than a value fixed
1.37 cvs 1387: for all time. Reference attributes are an exception to this norm. They cannot
1388: be assigned a fixed value, but when the name of such an attribute appears
1389: this indicates that this element type must have a valid value for the
1390: attribute. For the other attribute types, the fixed value is indicated by a
1.1 cvs 1391: signed integer (numeric attributes), a character string between apostrophes
1.18 cvs 1392: (textual attributes) or the name of a value (enumeration attributes).</p>
1.30 cvs 1393:
1394: <p>Fixed-value attributes can either be <a href="#sectc325">global</a> or
1395: local to the element type for which they are fixed, but they must be declared
1396: before they are used.</p>
1397: <pre> FixedAttrSeq = FixedAttr < ',' FixedAttr > .
1.1 cvs 1398: FixedAttr = AttrID [ FixedOrModifVal ] .
1399: FixedOrModifVal = [ '?' ] '=' FixedValue .
1400: FixedValue = [ '-' ] NumValue / TextVal / AttrVal .
1401: NumValue = NUMBER .
1.18 cvs 1402: TextVal = STRING .</pre>
1403: </div>
1.1 cvs 1404:
1.18 cvs 1405: <div class="subsection">
1.37 cvs 1406: <h3><a name="sectc328" id="sectc328">Structure definitions</a></h3>
1.1 cvs 1407:
1.37 cvs 1408: <p>The structure of an element type can be a simple base type or a
1409: constructed type.</p>
1.30 cvs 1410:
1411: <p>For constructed types, it is frequently the case that similar structures
1.37 cvs 1412: appear in many places in a document. For example the contents of the
1.1 cvs 1413: abstract, of the introduction, and of a section can have the same structure,
1.37 cvs 1414: that of a sequence of paragraphs. In this case, a single, common structure
1.1 cvs 1415: can be defined (the paragraph sequence in this example), and the schema is
1416: written to indicate that each element type possesses this structure, as
1.18 cvs 1417: follows:</p>
1418: <pre> Abstract = Paragraph_sequence;
1.1 cvs 1419: Introduction = Paragraph_sequence;
1.18 cvs 1420: Section_contents = Paragraph_sequence;</pre>
1.30 cvs 1421:
1422: <p>The equals sign means ``has the same structure as''.</p>
1423:
1.37 cvs 1424: <p>If the element type defined is a simple base type, this is indicated by
1425: one of the keywords <tt>TEXT</tt>, <tt>GRAPHICS</tt>, <tt>SYMBOL</tt>, or
1426: <tt>PICTURE</tt>. If some local attributes must be associated with a base
1427: type, the keyword of the base type is followed by the declaration of the
1428: local attributes using the syntax <a href="#sectc327">presented above.</a></p>
1.30 cvs 1429:
1430: <p>In the case of an open choice, the type is indicated by the keyword
1.18 cvs 1431: <tt>UNIT</tt> for units or the keyword <tt>NATURE</tt> for objects having a
1432: structure defined by any other schema.</p>
1.30 cvs 1433:
1434: <p>A unit represents one of the two following categories:</p>
1.18 cvs 1435: <ul>
1.30 cvs 1436: <li>a base type: text, graphical element, symbol, picture,</li>
1.37 cvs 1437: <li>an element whose type is chosen from among the types defined as units
1438: in the <tt>UNITS</tt> section of the document's structure schema. It can
1.30 cvs 1439: also be chosen from among the types defined as <a
1440: href="#sectd3132">units</a> in the <a href="#sectc3212"><tt>UNITS</tt>
1441: section</a> of the structure schemas that defines the ancestors of the
1442: element to which the rule is applied.</li>
1.18 cvs 1443: </ul>
1.30 cvs 1444:
1445: <p>Before the creation of an element defined as a unit, Thot asks the user to
1.18 cvs 1446: choose between the categories of elements.</p>
1.30 cvs 1447:
1448: <p>Thus, the contents of a paragraph can be specified as a sequence of units,
1.1 cvs 1449: which will permit the inclusion in the paragraphs of character strings,
1450: symbols, and various elements, such as cross-references, if these are defined
1.18 cvs 1451: as units.</p>
1.30 cvs 1452:
1.37 cvs 1453: <p>A schema object (keyword <tt>NATURE</tt>) represents an object defined by
1454: a structure schema freely chosen from among the available schemas; in the
1455: case the element type is defined by the first rule (the root rule) of the
1456: chosen schema.</p>
1.30 cvs 1457:
1458: <p>If the element type defined is a constructed type, the list, aggregate,
1.37 cvs 1459: choice, and reference constructors are used. In this case the definition
1460: begins with a keyword identifying the constructor. This keyword is followed
1.18 cvs 1461: by a syntax specific to each constructor.</p>
1.30 cvs 1462:
1463: <p>The local attribute definitions appear after the name of the element type
1.18 cvs 1464: being defined, if this element type has <a href="#sectc327">local
1465: attributes</a>.</p>
1466: <pre> Definition = BaseType [ LocAttrSeq ] / Constr / Element .
1.1 cvs 1467: BaseType = 'TEXT' / 'GRAPHICS' / 'SYMBOL' / 'PICTURE' /
1468: 'UNIT' / 'NATURE' .
1469: Element = ElemID [ ExtOrDef ] .
1470: ExtOrDef = 'EXTERN' / 'INCLUDED' /
1471: [ LocAttrSeq ] '=' Definition .
1472: Constr = 'LIST' [ '[' min '..' max ']' ] 'OF'
1473: '(' DefWithAttr ')' /
1474: 'BEGIN' DefOptSeq 'END' /
1475: 'AGGREGATE' DefOptSeq 'END' /
1476: 'CASE' 'OF' DefSeq 'END' /
1477: 'REFERENCE' '(' RefType ')' /
1.18 cvs 1478: 'PAIR' .</pre>
1.1 cvs 1479:
1.18 cvs 1480: <div class="subsubsection">
1.37 cvs 1481: <h4><a name="sectd3281" id="sectd3281">List</a></h4>
1.1 cvs 1482:
1.30 cvs 1483: <p>The list constructor permits the definition of an element type composed of
1.37 cvs 1484: a list of elements, all of the same type. A list definition begins with the
1.18 cvs 1485: <tt>LIST</tt> keyword followed by an optional range, the keyword <tt>OF</tt>,
1.1 cvs 1486: and the definition, between parentheses, of the element type which must
1.37 cvs 1487: compose the list. The optional range is composed of the minimum and maximum
1.1 cvs 1488: number of elements for the list separated by two periods and enclosed by
1.37 cvs 1489: brackets. If the range is not present, the number of list elements is
1490: unconstrained. When only one of the two bounds of the range is unconstrained,
1491: it is represented by a star ('*') character. Even when both bounds are
1492: unconstrained, they can be specified by <tt>[*..*]</tt>, but it is simpler
1493: not to specify any bound.</p>
1.18 cvs 1494: <pre> 'LIST' [ '[' min '..' max ']' ]
1.1 cvs 1495: 'OF' '(' DefWithAttr ')'
1496: min = Integer / '*' .
1497: max = Integer / '*' .
1.18 cvs 1498: Integer = NUMBER .</pre>
1.30 cvs 1499:
1500: <p>Before the document is edited, Thot creates the minimum number of elements
1.37 cvs 1501: for the list. If no minimum was given, it creates a single element. If a
1.30 cvs 1502: maximum number of elements is given and that number is attained, the editor
1503: refuses to create new elements for the list.</p>
1504:
1505: <blockquote class="example">
1506: <p><strong>Example:</strong></p>
1507:
1508: <p>The following two instructions define the body of a document as a
1509: sequence of at least two chapters and the contents of a section as a
1.37 cvs 1510: sequence of paragraphs. A single paragraph can be the entire contents of a
1.30 cvs 1511: section.</p>
1512: <pre>Body = LIST [2..*] OF (Chapter);
1.18 cvs 1513: Section_contents = LIST OF (Paragraph);</pre>
1514: </blockquote>
1515: </div>
1.1 cvs 1516:
1.18 cvs 1517: <div class="subsubsection">
1.37 cvs 1518: <h4><a name="sectd3282" id="sectd3282">Aggregate</a></h4>
1.1 cvs 1519:
1.37 cvs 1520: <p>The aggregate constructor is used to define an element type as a
1521: collection of sub-elements, each having a fixed type. The collection may be
1522: ordered or unordered. The elements composing the collection are called
1523: <em>components</em>. In the definition of an aggregate, a keyword indicates
1.18 cvs 1524: whether or not the aggregate is ordered: <tt>BEGIN</tt> for an ordered
1525: aggregate, <tt>AGGREGATE</tt> for an unordered aggregate. This keyword is
1.1 cvs 1526: followed by the list of component type definitions which is terminated by the
1.37 cvs 1527: <tt>END</tt> keyword. The component type definitions are separated by
1.18 cvs 1528: commas.</p>
1.30 cvs 1529:
1530: <p>Before creating an aggregate, the Thot editor creates all the aggregate's
1.1 cvs 1531: components in the order they appear in the structure schema, even for
1.37 cvs 1532: unordered aggregates. However, unlike ordered aggregates, the components of
1.1 cvs 1533: an unordered aggregate may be rearranged using operations of the Thot editor.
1534: The exceptions to the rule are any components whose name was preceded by a
1.37 cvs 1535: question mark character ('?'). These components, which are optional, can be
1.1 cvs 1536: created by explicit request, possibly at the time the aggregate is created,
1.18 cvs 1537: but they are not created automatically <em>prior</em> to the creation of the
1538: aggregate.</p>
1539: <pre> 'BEGIN' DefOptSeq 'END'
1.30 cvs 1540: DefOptSeq = DefOpt ';' < DefOpt ';' > .
1.18 cvs 1541: DefOpt = [ '?' ] DefWithAttr .</pre>
1.30 cvs 1542:
1.18 cvs 1543: <blockquote class="example">
1.30 cvs 1544: <p><strong>Example:</strong></p>
1545:
1546: <p>In a bilingual document, each paragraph has an English version and a
1.37 cvs 1547: French version. In certain cases, the translator wants to add a marginal
1548: note, but this note is present in very few paragraphs. Thus, it must not be
1549: created systematically for every paragraph. A bilingual paragraph of this
1.30 cvs 1550: type is declared:</p>
1551: <pre>Bilingual_paragraph = BEGIN
1.1 cvs 1552: French_paragraph = TEXT;
1553: English_paragraph = TEXT;
1554: ? Note = TEXT;
1.18 cvs 1555: END;</pre>
1556: </blockquote>
1557: </div>
1.1 cvs 1558:
1.18 cvs 1559: <div class="subsubsection">
1.37 cvs 1560: <h4><a name="sectd3283" id="sectd3283">Choice</a></h4>
1.1 cvs 1561:
1.30 cvs 1562: <p>The choice constructor permits the definition of an element type which is
1.37 cvs 1563: chosen from among a set of possible types. The keywords <tt>CASE</tt> and
1564: <tt>OF</tt> are followed by a list of definitions of possible types, which
1565: are separated by semicolons and terminated by the <tt>END</tt> keyword.</p>
1.18 cvs 1566: <pre> 'CASE' 'OF' DefSeq 'END'
1.30 cvs 1567: DefSeq = DefWithAttr ';' < DefWithAttr ';' > .</pre>
1568:
1569: <p>Before the creation of an element defined as a choice, the Thot editor
1.37 cvs 1570: presents the list of possible types for the element to the user. The user has
1.18 cvs 1571: only to select the element type that s/he wants to create from this list.</p>
1.30 cvs 1572:
1.37 cvs 1573: <p>The order of the type declarations is important. It determines the order
1574: of the list presented to the user before the creation of the element. Also,
1.30 cvs 1575: when a Choice element is being created automatically, the first type in the
1.37 cvs 1576: list is used. In fact, using the Thot editor, when an empty Choice element is
1.1 cvs 1577: selected, it is possible to select this element and to enter its text from
1578: keyboard. In this case, the editor uses the first element type which can
1.18 cvs 1579: contain an atom of the character string type.</p>
1.30 cvs 1580:
1581: <p>The two special cases of the choice constructor, the <a
1.18 cvs 1582: href="#sectc328"><em>schema</em></a> and the <a
1583: href="#sectc3212"><em>unit</em></a> are discussed elsewhere.</p>
1.30 cvs 1584:
1.18 cvs 1585: <blockquote class="example">
1.30 cvs 1586: <p><strong>Example:</strong></p>
1587:
1588: <p>It is common in documents to treat a variety of objects as if they were
1.37 cvs 1589: ordinary paragraphs. Thus, a ``Paragraph'' might actually be composed of a
1.30 cvs 1590: block of text (an ordinary paragraph), or a mathematical formula whose
1591: structure is defined by another structure schema named Math, or a table,
1.37 cvs 1592: also defined by another structure schema. Here is a definition of such a
1.30 cvs 1593: paragraph:</p>
1594: <pre>Paragraph = CASE OF
1.1 cvs 1595: Simple_text = TEXT;
1596: Formula = Math;
1597: Table_para = Table;
1.18 cvs 1598: END;</pre>
1599: </blockquote>
1600: </div>
1.1 cvs 1601:
1.18 cvs 1602: <div class="subsubsection">
1.37 cvs 1603: <h4><a name="sectd3284" id="sectd3284">Reference</a></h4>
1.1 cvs 1604:
1.37 cvs 1605: <p>Like all elements in Thot, references are typed. An element type defined
1.30 cvs 1606: as a reference is a cross-reference to an element of some other given type.
1607: The keyword <tt>REFERENCE</tt> is followed by the name of a type enclosed in
1.37 cvs 1608: parentheses. When the type which is being cross-referenced is defined in
1.1 cvs 1609: another structure schema, the type name is itself followed by the name of the
1.18 cvs 1610: external structure schema in which it is defined.</p>
1.30 cvs 1611:
1612: <p>When the designated element type is a <a href="#sectd3285">mark pair</a>,
1.37 cvs 1613: it can be preceded by a <tt>FIRST</tt> or <tt>SECOND</tt> keyword. These
1.18 cvs 1614: keywords indicate whether the reference points to the first or second mark of
1615: the pair. If the reference points to a pair and neither of these two keywords
1616: is present, the reference is considered to point to the first mark of the
1617: pair.</p>
1.30 cvs 1618:
1.37 cvs 1619: <p>There is an exception to the principle of typed references: it is possible
1.30 cvs 1620: to define a reference which designates an element of any type, which can
1621: either be in the same document or another document. In this case, it suffices
1622: to put the keyword <tt>ANY</tt> in the parentheses which indicate the
1623: referenced element type.</p>
1.18 cvs 1624: <pre> 'REFERENCE' '(' RefType ')'
1625: RefType = 'ANY' / [ FirstSec ] ElemID [ ExtStruct ] .</pre>
1.30 cvs 1626:
1627: <p>When defining an inclusion, the <tt>REFERENCE</tt> keyword is not used.
1.1 cvs 1628: Inclusions with complete expansion are not declared as such in the structure
1.37 cvs 1629: schemas, since any element defined in a structure schema can be replaced by
1630: an element of the same type. Instead, inclusions without expansion or with
1.1 cvs 1631: partial expansion must be declared explicitly whenever they will include a
1.37 cvs 1632: complete object ( and not a part of an object). In this case, the object type
1.1 cvs 1633: to be included (that is, the name of its structure schema) is followed by a
1.37 cvs 1634: keyword: <tt>EXTERN</tt> for inclusion without expansion and
1635: <tt>INCLUDED</tt> for partial expansion.</p>
1.30 cvs 1636:
1.37 cvs 1637: <p>Before creating a cross-reference or an inclusion, the Thot editor asks
1638: the user to choose, from the document images displayed, the referenced or
1639: included element.</p>
1.30 cvs 1640:
1.18 cvs 1641: <blockquote class="example">
1.30 cvs 1642: <p><strong>Example:</strong></p>
1643:
1644: <p>If the types Note and Section are defined in the Article structure
1645: schema, it is possible to define, in the same structure schema, a reference
1646: to a note and a reference to a section in this manner:</p>
1647: <pre>Ref_note = REFERENCE (Note);
1.18 cvs 1648: Ref_section = REFERENCE (Section);</pre>
1.30 cvs 1649:
1650: <p>It is also possible to define the generic structure of a collection of
1651: articles, which include (with partial expansion) objects of the Article
1652: class and which possess an introduction which may include cross-references
1.37 cvs 1653: to sections of the included articles. In the Collection structure schema,
1.30 cvs 1654: the definitions are:</p>
1655: <pre>Collection = BEGIN
1.6 cvs 1656: Collection_title = TEXT;
1657: Introduction = LIST OF (Elem = CASE OF
1.1 cvs 1658: TEXT;
1659: Ref_sect;
1660: END);
1.6 cvs 1661: Body = LIST OF (Article INCLUDED);
1662: END;
1.18 cvs 1663: Ref_sect = REFERENCE (Section (Article));</pre>
1.30 cvs 1664:
1665: <p>Here we define a Folder document class which has a title and includes
1666: documents of different types, particularly Folders:</p>
1667: <pre>Folder = BEGIN
1.6 cvs 1668: Folder_title = TEXT;
1669: Folder_contents = LIST OF (Document);
1670: END;
1.1 cvs 1671:
1672: Document = CASE OF
1673: Article EXTERN;
1674: Collection EXTERN;
1675: Folder EXTERN;
1.18 cvs 1676: END;</pre>
1.30 cvs 1677:
1678: <p>Under this definition, Folder represents either an aggregate which
1679: contains a folder title and the list of included documents or an included
1.37 cvs 1680: folder. To resolve this ambiguity, in the P language, the placement of a
1.30 cvs 1681: star character in front of the type name (here, Folder) indicates an
1682: included document.</p>
1.18 cvs 1683: </blockquote>
1684: </div>
1.1 cvs 1685:
1.18 cvs 1686: <div class="subsubsection">
1.37 cvs 1687: <h4><a name="sectd3285" id="sectd3285">Mark pairs</a></h4>
1.1 cvs 1688:
1.37 cvs 1689: <p>Like other elements, mark pairs are typed. The two marks of the pair have
1690: the same type, but there exist two predefined subtypes which apply to all
1691: mark pairs: the first mark of the pair (called <tt>First</tt> in the P and T
1.18 cvs 1692: languages) and the second mark (called <tt>Second</tt>).</p>
1.30 cvs 1693:
1694: <p>In the S language, a mark pair is noted simply by the <tt>PAIR</tt>
1.18 cvs 1695: keyword.</p>
1.30 cvs 1696:
1.37 cvs 1697: <p>In the Thot editor, marks are always moved or destroyed together. The two
1.1 cvs 1698: marks of a pair have the same identifier, unique within the document, which
1.18 cvs 1699: permits intertwining mark pairs without risk of ambiguity.</p>
1700: </div>
1701: </div>
1.1 cvs 1702:
1.18 cvs 1703: <div class="subsection">
1.37 cvs 1704: <h3><a name="sectc329" id="sectc329">Imports</a></h3>
1.1 cvs 1705:
1.30 cvs 1706: <p>Because of schema constructors, it is possible, before editing a document,
1.37 cvs 1707: to use classes defined by other structure schemas whenever they are needed.
1708: It is also possible to assign specific document classes to certain element
1709: types. In this case, these classes are simply designated by their name. In
1710: fact, if a type name is not defined in the structure schema, it is assumed
1711: that it specifies a structure defined by another structure schema.</p>
1.30 cvs 1712:
1.18 cvs 1713: <blockquote class="example">
1.30 cvs 1714: <p><strong>Example:</strong></p>
1715:
1716: <p>If the types Math and Table don't appear in the left part of a structure
1717: rule in the schema, the following two rules indicate that a formula has the
1.37 cvs 1718: structure of an object defined by the structure schema Math and that a
1719: table element has the structure of an object defined by the Table
1720: schema.</p>
1.30 cvs 1721: <pre>Formula = Math;
1.18 cvs 1722: Table_elem = Table;</pre>
1723: </blockquote>
1724: </div>
1725:
1726: <div class="subsection">
1.37 cvs 1727: <h3><a name="sectc3210" id="sectc3210">Extension rules</a></h3>
1.18 cvs 1728:
1.30 cvs 1729: <p>The <tt>EXTENS</tt> section, which can only appear in an extension schema,
1.1 cvs 1730: defines complements to the rules in the primary schema (i.e. the structure
1731: schema to which the extension schema will be applied). More precisely, this
1732: section permits the addition to an existing type of local attributes,
1.18 cvs 1733: extensions, restrictions and fixed-value attributes.</p>
1.30 cvs 1734:
1735: <p>These additions can be applied to the root rule of the primary schema,
1.18 cvs 1736: designated by the keyword <tt>Root</tt>, or to any other explicitly named
1737: rule.</p>
1.30 cvs 1738:
1739: <p>Extension rules are separated from each other by a semicolon and each
1.18 cvs 1740: extension rule has the same syntax as a <a href="#sectc327">structure
1741: rule</a>, but the part which defines the constructor is absent.</p>
1.30 cvs 1742: <pre> ExtenRuleSeq = ExtensRule ';' < ExtensRule ';' > .
1.6 cvs 1743: ExtensRule = RootOrElem [ LocAttrSeq ]
1744: [ '+' '(' ExtensionSeq ')' ]
1745: [ '-' '(' RestrictSeq ')' ]
1746: [ 'WITH' FixedAttrSeq ] .
1.18 cvs 1747: RootOrElem = 'Root' / ElemID .</pre>
1748: </div>
1.1 cvs 1749:
1.18 cvs 1750: <div class="subsection">
1.37 cvs 1751: <h3><a name="sectc3212" id="sectc3212">Units</a></h3>
1.30 cvs 1752:
1753: <p>The <tt>UNITS</tt> section of the structure schema contains the
1754: declarations of the element types which can be used in the external objects
1755: making up parts of the document or in objects of the class defined by the
1.37 cvs 1756: schema. These element types are defined just like other structured element
1757: types. They can be used in the other element types of the schema, but they
1758: can also be used in any other rule of the schema.</p>
1.30 cvs 1759:
1760: <blockquote class="example">
1761: <p><strong>Example:</strong></p>
1.1 cvs 1762:
1.30 cvs 1763: <p>If references to notes are declared as units:</p>
1764: <pre>UNITS
1.18 cvs 1765: Ref_note = REFERENCE (Note);</pre>
1.30 cvs 1766:
1.37 cvs 1767: <p>then it is possible to use references to notes in a cell of a table,
1768: even when <tt>Table</tt> is an external structure schema. The
1769: <tt>Table</tt> schema must declare a cell to be a sequence of units, which
1770: can then be base element types (text, for example) or references to notes
1771: in the document.</p>
1.30 cvs 1772: <pre>Cell = LIST OF (UNITS);</pre>
1.18 cvs 1773: </blockquote>
1774: </div>
1.1 cvs 1775:
1.18 cvs 1776: <div class="subsection">
1.37 cvs 1777: <h3><a name="sectc3213" id="sectc3213">Skeleton elements</a></h3>
1.1 cvs 1778:
1.30 cvs 1779: <p>When editing a document which contains or must contain external references
1780: to several other documents, it may be necessary to load a large number of
1.1 cvs 1781: documents, simply to see the parts designated by the external references of
1.37 cvs 1782: the document while editing, or to access the source of included elements. In
1783: this case, the external documents are not modified and it is only necessary
1784: to see the elements of these documents which could be referenced. Because of
1.1 cvs 1785: this, the editor will suggest that the documents be loaded in ``skeleton''
1.37 cvs 1786: form. This form contains only the elements of the document explicitly
1.18 cvs 1787: mentioned in the <tt>EXPORT</tt> section of their structure schema and, for
1.1 cvs 1788: these elements, only the part of the contents specified in that section. This
1789: form has the advantage of being very compact, thus requiring very few
1.37 cvs 1790: resources from the editor. This is also the skeleton form which constitutes
1.18 cvs 1791: the expanded form of <a href="#inclusion">inclusions</a> with partial
1792: expansion.</p>
1.30 cvs 1793:
1794: <p>Skeleton elements must be declared explicitly in the <tt>EXPORT</tt>
1.37 cvs 1795: section of the structure schema that defines them. This section begins with
1.30 cvs 1796: the keyword <tt>EXPORT</tt> followed by a comma-separated list of the element
1.1 cvs 1797: types which must appear in the skeleton form and ending with a semicolon.
1.18 cvs 1798: These types must have been previously declared in the schema.</p>
1.30 cvs 1799:
1.37 cvs 1800: <p>For each skeleton element type, the part of the contents which is loaded
1801: by the editor, and therefore displayable, can be specified by putting the
1802: keyword <tt>WITH</tt> and the name of the contained element type to be loaded
1803: after the name of the skeleton element type. In this case only that named
1804: element, among all the elements contained in the exportable element type,
1805: will be loaded. If the <tt>WITH</tt> is absent, the entire contents of the
1806: skeleton element will be loaded by the editor. If instead, it is better that
1807: the skeleton form not load the contents of a particular element type, the
1808: keyword <tt>WITH</tt> must be followed by the word <tt>Nothing</tt>.</p>
1.18 cvs 1809: <pre> [ 'EXPORT' SkeletonSeq ]
1.1 cvs 1810:
1.30 cvs 1811: SkeletonSeq = SkelElem < ',' SkelElem > ';' .
1.1 cvs 1812: SkelElem = ElemID [ 'WITH' Contents ] .
1.18 cvs 1813: Contents = 'Nothing' / ElemID [ ExtStruct ] .</pre>
1.30 cvs 1814:
1.18 cvs 1815: <blockquote class="example">
1.30 cvs 1816: <p><strong>Example:</strong></p>
1817:
1818: <p>Suppose that, in documents of the article class, the element types
1819: Article_title, Figure, Section, Paragraph, and Biblio should appear in the
1820: skeleton form in order to make it easier to create external references to
1.37 cvs 1821: them from other documents. When loading an article in its skeleton form,
1.30 cvs 1822: all of these element types will be loaded except for paragraphs, but only
1.37 cvs 1823: the article title will be loaded in its entirety. For figures, the caption
1.30 cvs 1824: will be loaded, while for sections, the title will be loaded, and for
1.37 cvs 1825: bibliographic entries, only the title that they contain will be loaded.
1826: Note that bibliographic elements are defined in another structure schema,
1827: RefBib. To produce this result, the following declarations should be placed
1828: in the Article structure schema:</p>
1.30 cvs 1829: <pre>EXPORT
1.1 cvs 1830: Article_title,
1.5 cvs 1831: Figure With Caption,
1.1 cvs 1832: Section With Section_title,
1833: Paragraph With Nothing,
1.18 cvs 1834: Biblio With Biblio_title(RefBib);</pre>
1835: </blockquote>
1836: </div>
1.1 cvs 1837:
1.18 cvs 1838: <div class="subsection">
1.37 cvs 1839: <h3><a name="sectc3214" id="sectc3214">Exceptions</a></h3>
1.1 cvs 1840:
1.30 cvs 1841: <p>The behavior of the Thot editor and the actions that it performs are
1.37 cvs 1842: determined by the structure schemas. These actions are applied to all
1843: document and object types in accordance with their generic structure. For
1.1 cvs 1844: certain object types, such as tables and graphics, these actions are not
1845: sufficient or are poorly adapted and some special actions must be added to or
1.37 cvs 1846: substituted for certain standard actions. These special actions are called
1.18 cvs 1847: <em>exceptions</em>.</p>
1.30 cvs 1848:
1.37 cvs 1849: <p>Exceptions only inhibit or modify certain standard actions, but they can
1850: be used freely in every structure schema.</p>
1.30 cvs 1851:
1.37 cvs 1852: <p>Each structure schema can contain a section defining exceptions. It begins
1.18 cvs 1853: with the keyword <tt>EXCEPT</tt> and is composed of a sequence of exception
1.37 cvs 1854: declarations, separated by semicolons. Each declaration of an exception
1855: begins with the name of an element type or attribute followed by a colon.
1856: This indicates the element type or attribute to which the following
1857: exceptions apply. When the given element type name is a <a
1858: href="#sectd3285">mark pair</a>, and only in this case, the type name can be
1859: preceded by the keyword <tt>First</tt> or <tt>Second</tt>, to indicate if the
1860: exceptions which follow are associated with the first mark of the pair or the
1861: second. In the absence of this keyword, the first mark is used.</p>
1.30 cvs 1862:
1863: <p>When placed in an <a href="#sectc322">extension schema</a>, the keyword
1.18 cvs 1864: <tt>EXTERN</tt> indicates that the type name which follows is found in the
1.37 cvs 1865: principal schema (the schema being extended by the extension schema). The
1866: exceptions are indicated by a name. They are separated by semicolons.</p>
1.18 cvs 1867: <pre> [ 'EXCEPT' ExceptSeq ]
1.1 cvs 1868:
1.30 cvs 1869: ExceptSeq = Except ';' < Except ';' > .
1.1 cvs 1870: Except = [ 'EXTERN' ] [ FirstSec ] ExcTypeOrAttr
1871: ':' ExcValSeq .
1872: ExcTypeOrAttr = ElemID / AttrID .
1.30 cvs 1873: ExcValSeq = ExcValue < ',' ExcValue > .
1.19 cvs 1874: ExcValue ='NoCut' / 'NoCreate' / 'NoHMove' /
1875: 'NoVMove' / 'NoHResize' / 'NoVResize' /
1876: 'NoMove' / 'NoResize' / 'MoveResize' /
1877: 'NewWidth' / 'NewHeight' / 'NewHPos' /
1878: 'NewVPos' / 'Invisible' /
1.28 cvs 1879: 'NoSelect' / 'NoSpellCheck' /
1.1 cvs 1880: 'Hidden' / 'ActiveRef' /
1881: 'ImportLine' / 'ImportParagraph' /
1882: 'NoPaginate' / 'ParagraphBreak' /
1.19 cvs 1883: 'PageBreak' / 'PageBreakAllowed' / 'PageBreakPlace' /
1884: 'PageBreakRepetition' / 'PageBreakRepBefore' /
1.9 cvs 1885: 'HighlightChildren' / 'ExtendedSelection' /
1.36 cvs 1886: 'SelectParent' / 'ClickableSurface' /
1.29 cvs 1887: 'ReturnCreateNL' / 'ReturnCreateWithin' /
1888: 'IsDraw' / 'IsTable' /
1.19 cvs 1889: 'IsRow' / 'IsColHead' / 'IsCell' /
1890: 'NewPercentWidth' / 'ColRef' / 'ColSpan' /
1891: 'RowSpan' / 'SaveDocument' / 'Shadow' .</pre>
1.30 cvs 1892:
1893: <p>The following are the available exceptions:</p>
1.18 cvs 1894: <dl>
1.30 cvs 1895: <dt><tt>NoCut</tt></dt>
1.37 cvs 1896: <dd>This exception can only be applied to element types. Elements of a
1.30 cvs 1897: type to which this exception is applied cannot be deleted by the
1898: editor.</dd>
1899: <dt><tt>NoCreate</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 created by ordinary
1.37 cvs 1902: commands for creating new elements. These elements are usually created
1.30 cvs 1903: by special actions associated with other exceptions.</dd>
1904: <dt><tt>NoHMove</tt></dt>
1.37 cvs 1905: <dd>This exception can only be applied to element types. Elements of a
1.30 cvs 1906: type to which this exception is applied cannot be moved horizontally
1907: with the mouse. Their children elements cannot be moved either.</dd>
1908: <dt><tt>NoVMove</tt></dt>
1.37 cvs 1909: <dd>This exception can only be applied to element types. Elements of a
1.30 cvs 1910: type to which this exception is applied cannot be moved vertically with
1911: the mouse. Their children elements cannot be moved either.</dd>
1912: <dt><tt>NoMove</tt></dt>
1.37 cvs 1913: <dd>This exception can only be applied to element types. Elements of a
1914: type to which this exception is applied cannot be moved in any
1915: direction with the mouse. Their children elements cannot be moved
1916: either.</dd>
1.30 cvs 1917: <dt><tt>NoHResize</tt></dt>
1.37 cvs 1918: <dd>This exception can only be applied to element types. Elements of a
1.30 cvs 1919: type to which this exception is applied cannot be resized horizontally
1920: with the mouse. Their children elements cannot be resized either.</dd>
1921: <dt><tt>NoVResize</tt></dt>
1.37 cvs 1922: <dd>This exception can only be applied to element types. Elements of a
1.30 cvs 1923: type to which this exception is applied cannot be resized vertically
1924: with the mouse. Their children elements cannot be resized either.</dd>
1925: <dt><tt>NoResize</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 cannot be resized in any
1.37 cvs 1928: direction with the mouse. Their children elements cannot be resized
1.30 cvs 1929: either.</dd>
1930: <dt><tt>MoveResize</tt></dt>
1.37 cvs 1931: <dd>This exception can only be applied to element types. Elements of a
1.30 cvs 1932: type to which this exception is applied can be moved and resized in any
1933: direction with the mouse, even if one of their ancestor element has an
1.37 cvs 1934: exception that prevents moving or resizing. Their children elements can
1.30 cvs 1935: also be resized or moved.</dd>
1936: <dt><tt>NewWidth</tt></dt>
1.37 cvs 1937: <dd>This exception can only be applied to numeric attributes. If the
1938: width of an element which has this attribute is modified with the
1939: mouse, the value of the new width will be assigned to the
1940: attribute.</dd>
1.30 cvs 1941: <dt><tt>NewHeight</tt></dt>
1.37 cvs 1942: <dd>This exception can only be applied to numeric attributes. If the
1.30 cvs 1943: height of an element which has this attribute is modified with the
1944: mouse, the value of the new height will be assigned to the
1945: attribute.</dd>
1946: <dt><tt>NewHPos</tt></dt>
1.37 cvs 1947: <dd>This exception can only be applied to numeric attributes. If the
1.30 cvs 1948: horizontal position of an element which has this attribute is modified
1949: with the mouse, the value of the new horizontal position will be
1950: assigned to the attribute.</dd>
1951: <dt><tt>NewVPos</tt></dt>
1.37 cvs 1952: <dd>This exception can only be applied to numeric attributes. If the
1.30 cvs 1953: vertical position of an element which has this attribute is modified
1954: with the mouse, the value of the new vertical position will be assigned
1955: to the attribute.</dd>
1956: <dt><tt>Invisible</tt></dt>
1957: <dd>This exception can only be applied to attributes, but can be applied
1.37 cvs 1958: to all attribute types. It indicates that the attribute must not be
1959: seen by the user and that its value must not be changed directly. This
1.30 cvs 1960: exception is usually used when another exception manipulates the value
1961: of an attribute.</dd>
1962: <dt><tt>NoSelect</tt></dt>
1.37 cvs 1963: <dd>This exception can only be applied to element types. Elements of a
1964: type to which this exception is applied cannot be selected directly
1.30 cvs 1965: with the mouse, but they can be selected by other methods provided by
1966: the editor.</dd>
1967: <dt>NoSpellCheck</dt>
1.37 cvs 1968: <dd>This exception can only be applied to element types. Elements of a
1.30 cvs 1969: type to which this exception is applied are not taken into account by
1970: the spell checker.</dd>
1971: <dt><tt>Hidden</tt></dt>
1.37 cvs 1972: <dd>This exception can only be applied to element types. It indicates
1.30 cvs 1973: that elements of this type, although present in the document's
1.37 cvs 1974: structure, must not be shown to the user of the editor. In particular,
1.30 cvs 1975: the creation menus must not propose this type and the selection message
1976: must not pick it.</dd>
1977: <dt><tt>ActiveRef</tt></dt>
1978: <dd>This exception can only be applied to attributes of the reference
1.37 cvs 1979: type. It indicates that when the user of the editor makes a double
1.30 cvs 1980: click on an element which possesses a reference attribute having this
1981: exception, the element designated by the reference attribute will be
1982: selected.</dd>
1983: <dt><tt>ImportLine</tt></dt>
1.37 cvs 1984: <dd>This exception can only be applied to element types. It indicates
1.30 cvs 1985: that elements of this type should receive the content of imported text
1.37 cvs 1986: files. An element is created for each line of the imported file. A
1.30 cvs 1987: structure schema cannot contain several exceptions <tt>ImportLine</tt>
1988: and, if it contains one, it should not contain any exception
1989: <tt>ImportParagraph</tt>.</dd>
1990: <dt><tt>ImportParagraph</tt></dt>
1.37 cvs 1991: <dd>This exception can only be applied to element types. It indicates
1.30 cvs 1992: that elements of this type should receive the content of imported text
1.37 cvs 1993: files. An element is created for each paragraph of the imported file. A
1994: paragraph is a sequence of lines without any empty line. A structure
1.30 cvs 1995: schema cannot contain several exceptions <tt>ImportParagraph</tt> and,
1996: if it contains one, it should not contain any exception
1997: <tt>ImportLine</tt>.</dd>
1998: <dt><tt>NoPaginate</tt></dt>
1999: <dd>This exception can only be applied to the root element, i.e. the name
1.37 cvs 2000: that appear after the keyword <tt>STRUCTURE</tt> at the beginning of
2001: the structure schema. It indicates that the editor should not allow the
1.30 cvs 2002: user to paginate documents of that type.</dd>
2003: <dt><tt>ParagraphBreak</tt></dt>
1.37 cvs 2004: <dd>This exception can only be applied to element types. When the caret
2005: is within an element of a type to which this exception is applied, it
2006: is that element that will be split when the user hits the Return
2007: key.</dd>
1.30 cvs 2008: <dt><tt>ReturnCreateNL</tt></dt>
1.37 cvs 2009: <dd>This exception can only be applied to element types. When the caret
1.30 cvs 2010: is within an element of a type to which this exception is applied, the
2011: Return key simply inserts a New line character (code \212) at the
2012: current position. The Return key does not create a new element; it does
2013: not split the current element either.</dd>
2014: <dt><tt>ReturnCreateWithin</tt></dt>
1.37 cvs 2015: <dd>This exception can only be applied to element types. When the caret
1.30 cvs 2016: is within an element of a type to which this exception is applied, the
2017: Return key will create a new element within that element, not a sibling
2018: after that element.</dd>
2019: <dt><tt>HighlightChildren</tt></dt>
1.37 cvs 2020: <dd>This exception can only be applied to element types. Elements of a
1.30 cvs 2021: type to which this exception is applied are not highlighted themselves
1.32 cvs 2022: when they are selected in the main view, but all their children are
1.37 cvs 2023: highlighted instead. If children have this exception too, the process
2024: is applied recursively. Only the main view defined in the presentation
1.32 cvs 2025: schema is concerned. Tee exception is ignored for other views.</dd>
1.30 cvs 2026: <dt><tt>ExtendedSelection</tt></dt>
1.37 cvs 2027: <dd>This exception can only be applied to element types. The selection
1.30 cvs 2028: extension command (middle button of the mouse) only add the clicked
2029: element (if it has that exception) to the current selection, without
2030: selecting other elements between the current selection and the clicked
2031: element.</dd>
1.36 cvs 2032: <dt><code>SelectParent</code></dt>
2033: <dd>This exception can only be applied to element types. When the user
1.37 cvs 2034: clicks on an element of that type, the parent of the element is
2035: selected instead of the element itself.</dd>
1.36 cvs 2036: <dt><code>ClickableSurface</code></dt>
2037: <dd>This exception can only be applied to element types. When the user
1.37 cvs 2038: clicks within a child of an element of that type, this child is
2039: selected even if it is a graphic leaf that is not filled.</dd>
1.36 cvs 2040: <dt><code>IsDraw</code>, <code>IsTable</code>, <code>IsColHead</code>,
2041: <code>IsRow</code>, <code>IsCell</code></dt>
1.37 cvs 2042: <dd>These exceptions can only be applied to element types. Elements of a
1.30 cvs 2043: type to which these exceptions are applied are identified as Draws,
2044: Tables, Colheads, Rows or Cells and specific processing are applied to
2045: them.</dd>
1.36 cvs 2046: <dt><code>ColRef</code></dt>
1.30 cvs 2047: <dd>This exception can only be applied to attributes of the reference
2048: type. It indicates that this attribute refers to the column head (see
2049: exception IsColHead) which the element belongs to.</dd>
1.36 cvs 2050: <dt><code>ColSpan</code>, <code>RowSpan</code></dt>
1.31 cvs 2051: <dd>These exceptions can only be applied to numeric attributes of cells.
1.30 cvs 2052: They indicate that attribute values give how many columns or rows the
2053: element spans.</dd>
1.36 cvs 2054: <dt><code>Shadow</code></dt>
1.37 cvs 2055: <dd>This exception can only be applied to element types. Text of elements
1.30 cvs 2056: of a type to which this exception is applied are displayed and printed
2057: as a set of stars ('*').</dd>
1.18 cvs 2058: </dl>
1.30 cvs 2059:
1.18 cvs 2060: <blockquote class="example">
1.30 cvs 2061: <p><strong>Example:</strong></p>
2062:
2063: <p>Consider a structure schema for object-style graphics which defines the
2064: Graphic_object element type with the associated Height and Weight numeric
1.37 cvs 2065: attributes. Suppose that we want documents of this class to have the
1.30 cvs 2066: following qualities:</p>
2067: <ul>
2068: <li>Whenever the width or height of an object is changed using the mouse,
2069: the new values are stored in the object's Width and Height
2070: attributes.</li>
2071: <li>The user should not be able to change the values of the Width and
2072: Height attributes via the Attributes menu of the Thot editor.</li>
2073: </ul>
2074:
2075: <p>The following exceptions will produce this effect.</p>
2076: <pre>STRUCT
1.1 cvs 2077: ...
1.5 cvs 2078: Graphics_object (ATTR Height = Integer; Width = Integer)
1.1 cvs 2079: = GRAPHICS with Height ?= 10, Width ?= 10;
2080: ...
2081: EXCEPT
2082: Height: NewHeight, Invisible;
1.18 cvs 2083: Width: NewWidth, Invisible;</pre>
2084: </blockquote>
2085: </div>
2086: </div>
1.1 cvs 2087:
1.18 cvs 2088: <div class="section">
1.37 cvs 2089: <h2><a name="sectb33" id="sectb33">Some examples</a></h2>
1.1 cvs 2090:
1.30 cvs 2091: <p>In order to illustrate the principles of the document model and the syntax
2092: of the S language, this section presents two examples of structure schemas.
2093: One defines a class of documents, the other defines a class of objects.</p>
1.1 cvs 2094:
1.18 cvs 2095: <div class="subsection">
1.37 cvs 2096: <h3><a name="sectc331" id="sectc331">A class of documents: articles</a></h3>
1.1 cvs 2097:
1.30 cvs 2098: <p>This example shows a possible structure for articles published in a
2099: journal. Text between braces is comments.</p>
1.18 cvs 2100: <pre>STRUCTURE Article; { This schema defines the Article class }
1.1 cvs 2101: DEFPRES ArticleP; { The default presentation schema is
2102: ArticleP }
2103: ATTR { Global attribute definitions }
2104: WordType = Definition, IndexWord, DocumentTitle;
2105: { A single global attribute is defined, with three values }
2106: STRUCT { Definition of the generic structure }
2107: Article = BEGIN { The Article class has an aggregate
2108: structure }
2109: Title = BEGIN { The title is an aggregate }
2110: French_title =
2111: Text WITH Language='Fran\347ais';
2112: English_title =
2113: Text WITH Language='English';
2114: END;
2115: Authors =
2116: LIST OF (Author
2117: (ATTR Author_type=principal,secondary)
2118: { The Author type has a local attribute }
2119: = BEGIN
2120: Author_name = Text;
2121: Info = Paragraphs ;
2122: { Paragraphs is defined later }
2123: Address = Text;
2124: END
2125: );
2126: Keywords = Text;
2127: { The journal's editor introduces the article
2128: with a short introduction, in French and
2129: in English }
2130: Introduction =
2131: BEGIN
2132: French_intr = Paragraphs WITH
2133: Language='Fran\347ais';
2134: English_intr = Paragraphs WITH
2135: Language='English';
2136: END;
2137: Body = Sections; { Sections are defined later }
2138: { Appendixes are only created on demand }
2139: ? Appendices =
2140: LIST OF (Appendix =
2141: BEGIN
2142: Appendix_Title = Text;
2143: Appendix_Contents = Paragraphs;
2144: END
2145: );
1.37 cvs 2146: ? Figures = LIST OF (Figure);
2147: ? Bibliography = LIST OF (Biblio_citation);
2148: ? Notes = LIST OF (Note);
1.1 cvs 2149: END; { End of the Article aggregate }
2150:
2151: Sections = LIST [2..*] OF (
2152: Section = { At least 2 sections }
2153: BEGIN
2154: Section_title = Text;
2155: Section_contents =
2156: BEGIN
2157: Paragraphs;
2158: Sections; { Sections at a lower level }
2159: END;
2160: END
2161: );
2162:
2163: Paragraphs = LIST OF (Paragraph = CASE OF
2164: Enumeration =
2165: LIST [2..*] OF
2166: (Item = Paragraphs);
2167: Isolated_formula = Formula;
2168: LIST OF (UNIT);
2169: END
2170: );
2171:
2172: Figure = BEGIN
1.5 cvs 2173: Figure_caption = Text;
1.1 cvs 2174: Illustration = NATURE;
2175: END;
2176:
2177: Biblio_citation = CASE OF
2178: Ref_Article =
2179: BEGIN
2180: Authors_Bib = Text;
2181: Article_Title = Text;
2182: Journal = Text;
2183: Page_Numbers = Text;
2184: Date = Text;
2185: END;
2186: Ref_Livre =
2187: BEGIN
2188: Authors_Bib; { Defined above }
2189: Book_Title = Text;
2190: Editor = Text;
2191: Date; { Defined above }
2192: END;
2193: END;
2194:
2195: Note = Paragraphs - (Ref_note);
2196:
2197: UNITS { Elements which can be used in objects }
2198:
2199: Ref_note = REFERENCE (Note);
2200: Ref_biblio = REFERENCE (Biblio_citation);
2201: Ref_figure = REFERENCE (Figure);
2202: Ref_formula = REFERENCE (Isolated_formula);
2203:
2204: EXPORT { Skeleton elements }
2205:
2206: Title,
1.5 cvs 2207: Figure with Figure_caption,
1.1 cvs 2208: Section With Section_title;
2209:
1.18 cvs 2210: END { End of the structure schema }</pre>
1.30 cvs 2211:
2212: <p>This schema is very complete since it defines both paragraphs and
1.37 cvs 2213: bibliographic citations. These element types could just as well be defined in
2214: other structure schemas, as is the case with the <tt>Formula</tt> class. All
2215: sorts of other elements can be inserted into an article, since a paragraph
2216: can contain any type of unit. Similarly, figures can be any class of document
2217: or object that the user chooses.</p>
2218:
2219: <p>Generally, an article doesn't contain appendices, but it is possible to
2220: add them on explicit request: this is the effect of the question mark before
2221: the word Appendices.</p>
1.30 cvs 2222:
1.37 cvs 2223: <p>Various types of cross-references can be put in paragraphs. They can also
1.30 cvs 2224: be placed the objects which are part of the article, since the
2225: cross-references are defined as units (<tt>UNITS</tt>).</p>
2226:
2227: <p>There is a single restriction to prevent the creation of Ref_note elements
1.18 cvs 2228: within notes.</p>
1.30 cvs 2229:
2230: <p>It is worth noting that the S language permits the definition of recursive
1.37 cvs 2231: structures like sections: a section can contain other sections (which are
2232: thus at the next lower level of the document tree). Paragraphs are also
2233: recursive elements, since a paragraph can contain an enumeration in which
2234: each element (<tt>Item</tt>) is composed of paragraphs.</p>
1.18 cvs 2235: </div>
1.1 cvs 2236:
1.18 cvs 2237: <div class="subsection">
1.37 cvs 2238: <h3><a name="sectc332" id="sectc332">A class of objects: mathematical
2239: formulas</a></h3>
1.1 cvs 2240:
1.30 cvs 2241: <p>The example below defines the <tt>Formula</tt> class which is used in
1.37 cvs 2242: Article documents. This class represents mathematical formulas with a rather
1.30 cvs 2243: simple structure, but sufficient to produce a correct rendition on the screen
1.37 cvs 2244: or printer. To support more elaborate operations (formal or numeric
2245: calculations), a finer structure should be defined. This class doesn't use
2246: any other class and doesn't define any units.</p>
1.18 cvs 2247: <pre>STRUCTURE Formula;
1.1 cvs 2248: DEFPRES FormulaP;
2249:
2250: ATTR
2251: String_type = Function_name, Variable_name;
2252:
2253: STRUCT
2254: Formula = Expression;
2255: Expression = LIST OF (Construction);
2256: Construction = CASE OF
2257: TEXT; { Simple character string }
2258: Index = Expression;
2259: Exponent = Expression;
2260: Fraction =
2261: BEGIN
1.6 cvs 2262: Numerator = Expression;
1.1 cvs 2263: Denominator = Expression;
2264: END;
2265: Root =
2266: BEGIN
2267: ? Order = TEXT;
2268: Root_Contents = Expression;
2269: END;
2270: Integral =
2271: BEGIN
2272: Integration_Symbol = SYMBOL;
2273: Lower_Bound = Expression;
2274: Upper_Bound = Expression;
2275: END;
2276: Triple =
2277: BEGIN
2278: Princ_Expression = Expression;
2279: Lower_Expression = Expression;
2280: Upper_Expression = Expression;
2281: END;
2282: Column = LIST [2..*] OF
2283: (Element = Expression);
2284: Parentheses_Block =
2285: BEGIN
2286: Opening = SYMBOL;
2287: Contents = Expression;
2288: Closing = SYMBOL;
2289: END;
2290: END; { End of Choice Constructor }
1.18 cvs 2291: END { End of Structure Schema }</pre>
1.30 cvs 2292:
2293: <p>This schema defines a single global attribute which allows functions and
1.37 cvs 2294: variables to be distinguished. In the presentation schema, this attribute can
1.1 cvs 2295: be used to choose between roman (for functions) and italic characters (for
1.18 cvs 2296: variables).</p>
1.30 cvs 2297:
1.37 cvs 2298: <p>A formula's structure is that of a mathematical expression, which is
2299: itself a sequence of mathematical constructions. A mathematical construction
2300: can be either a simple character string, an index, an exponent, a fraction, a
2301: root, etc. Each of these mathematical constructions has a sensible structure
2302: which generally includes one or more expressions, thus making the formula
2303: class's structure definition recursive.</p>
1.30 cvs 2304:
2305: <p>In most cases, the roots which appear in the formulas are square roots and
1.37 cvs 2306: their order (2) is not specified. This is why the Order component is marked
2307: optional by a question mark. When explicitly requested, it is possible to add
1.18 cvs 2308: an order to a root, for example for cube roots (order = 3).</p>
1.30 cvs 2309:
2310: <p>An integral is formed by an integration symbol, chosen by the user (simple
1.37 cvs 2311: integral, double, curvilinear, etc.), and two bounds. A more fine-grained
1.1 cvs 2312: schema would add components for the integrand and the integration variable.
1.37 cvs 2313: Similarly, the Block_Parentheses construction leaves the choice of opening
2314: and closing symbols to the user. They can be brackets, braces, parentheses,
1.18 cvs 2315: etc.</p>
2316: </div>
2317: </div>
1.37 cvs 2318: <hr />
1.18 cvs 2319: </div>
1.1 cvs 2320:
1.18 cvs 2321: <div class="chapter">
1.37 cvs 2322: <h1><a name="sect4" id="sect4">The P Language</a></h1>
1.1 cvs 2323:
1.18 cvs 2324: <div class="section">
1.37 cvs 2325: <h2><a name="sectb41" id="sectb41">Document presentation</a></h2>
1.1 cvs 2326:
1.30 cvs 2327: <p>Because of the model adopted for Thot, the presentation of documents is
1.37 cvs 2328: clearly separated from their structure and content. After having presented
1.1 cvs 2329: the logical structure of documents, we now detail the principles implemented
1.37 cvs 2330: for their presentation. The concept of <em>presentation</em> encompasses what
2331: is often called the page layout, the composition, or the document style. It
1.18 cvs 2332: is the set of operations which display the document on the screen or print it
1.37 cvs 2333: on paper. Like logical structure, document presentation is defined
1.18 cvs 2334: generically with the help of a language, called P.</p>
1.1 cvs 2335:
1.18 cvs 2336: <div class="subsection">
1.37 cvs 2337: <h3><a name="sectc411" id="sectc411">Two levels of presentation</a></h3>
1.1 cvs 2338:
1.30 cvs 2339: <p>The link between structure and presentation is clear: the logical
2340: organization of a document is used to carry out its presentation, since the
2341: purpose of the presentation is to make evident the organization of the
1.37 cvs 2342: document. But the presentation is equally dependent on the device used to
1.30 cvs 2343: render the document. Certain presentation effects, notably changes of font or
1.37 cvs 2344: character set, cannot be performed on all printers or on all screens. This is
1.30 cvs 2345: why Thot uses a two-level approach, where the presentation is first described
2346: in abstract terms, without taking into account each particular device, and
2347: then the presentation is realized within the constraints of a given
2348: device.</p>
2349:
2350: <p>Thus, presentation is only described as a function of the structure of the
1.37 cvs 2351: documents and the image that would be produced on an idealized device. For
1.1 cvs 2352: this reason, presentation descriptions do not refer to any device
1.18 cvs 2353: characteristics: they describe <em>abstract presentations</em> which can be
2354: concretized on different devices.</p>
1.30 cvs 2355:
2356: <p>A presentation description also defines a <em>generic presentation</em>,
2357: since it describes the appearance of a class of documents or objects. This
2358: generic presentation must also be applied to document and object instances,
2359: each conforming to its generic logical structure, but with all the allowances
2360: that were called to mind above: missing elements, constructed elements with
2361: other logical structures, etc.</p>
2362:
2363: <p>In order to preserve the homogeneity between documents and objects,
1.1 cvs 2364: presentation is described with a single set of tools which support the layout
2365: of a large document as well as the composition of objects like a graphical
1.37 cvs 2366: figure or mathematical formula. This unity of presentation description tools
1.1 cvs 2367: contrasts with the traditional approach, which focuses more on documents than
2368: objects and thus is based on the usual typographic conventions, such as the
2369: placement of margins, indentations, vertical spaces, line lengths,
1.18 cvs 2370: justification, font changes, etc.</p>
2371: </div>
1.1 cvs 2372:
1.18 cvs 2373: <div class="subsection">
1.37 cvs 2374: <h3><a name="sectc412" id="sectc412">Boxes</a></h3>
1.1 cvs 2375:
1.37 cvs 2376: <p>To assure the homogeneity of tools, all presentation in Thot, for
2377: documents as well as for the objects which they contain, is based on the
2378: notion of the <em>box</em>, such as was implemented in
2379: T<sub><big>E</big></sub>X.</p>
1.30 cvs 2380:
1.37 cvs 2381: <p>Corresponding to each element of the document is a box, which is the
1.1 cvs 2382: rectangle enclosing the element on the display device (screen or sheet of
1.37 cvs 2383: paper); the outline of this rectangle is not visible, except when a <a
2384: href="#sectc4230a"><tt>ShowBox</tt> rule</a> applies to the element. The
2385: sides of the box are parallel to the sides of the screen or the sheet of
2386: paper. By way of example, a box is associated with a character string, a line
2387: of text, a page, a paragraph, a title, a mathematical formula, or a table
2388: cell.</p>
1.30 cvs 2389:
2390: <p>Whatever element it corresponds to, each box possesses four sides and four
1.18 cvs 2391: axes, which we designate as follows (<a href="#boxes">see figure</a>):</p>
2392: <dl>
1.30 cvs 2393: <dt><tt>Top</tt></dt>
2394: <dd>the upper side,</dd>
2395: <dt><tt>Bottom</tt></dt>
2396: <dd>the lower side,</dd>
2397: <dt><tt>Left</tt></dt>
2398: <dd>the left side,</dd>
2399: <dt><tt>Right</tt></dt>
2400: <dd>the right side,</dd>
2401: <dt><tt>VMiddle</tt></dt>
2402: <dd>the vertical axis passing through the center of the box,</dd>
2403: <dt><tt>HMiddle</tt></dt>
2404: <dd>the horizontal axis passing through the center of the box,</dd>
2405: <dt><tt>VRef</tt></dt>
2406: <dd>the vertical reference axis,</dd>
2407: <dt><tt>HRef</tt></dt>
2408: <dd>the horizontal reference axis.</dd>
1.18 cvs 2409: </dl>
2410:
2411: <div class="figure">
1.37 cvs 2412: <hr />
1.18 cvs 2413: <pre> Left VRef VMiddle Right
1.1 cvs 2414: : :
2415: Top -----------------------------
2416: | : : |
2417: | : : |
2418: | : : |
2419: | : : |
2420: | : : |
2421: HMiddle ..|...........................|..
2422: | : : |
2423: | : : |
2424: HRef ..|...........................|..
2425: | : : |
2426: | : : |
2427: Bottom -----------------------------
1.18 cvs 2428: : :</pre>
1.30 cvs 2429:
1.37 cvs 2430: <p align="center"><em><a name="boxes" id="boxes">The sides and axes of
1.30 cvs 2431: boxes</a><em></em></em></p>
1.37 cvs 2432: <hr />
1.30 cvs 2433: </div>
1.19 cvs 2434:
1.37 cvs 2435: <p>The principal role of boxes is to set the extent and position of the
2436: images of the different elements of a document with respect to each other on
2437: the reproduction device. This is done by defining relations between the boxes
2438: of different elements which give relative extents and positions to these
1.18 cvs 2439: boxes.</p>
1.30 cvs 2440:
2441: <p>There are three types of boxes:</p>
1.18 cvs 2442: <ul>
1.30 cvs 2443: <li>boxes corresponding to structural elements of the document,</li>
2444: <li>presentation boxes,</li>
2445: <li>page layout boxes.</li>
1.18 cvs 2446: </ul>
1.30 cvs 2447:
1.37 cvs 2448: <p><strong>Boxes corresponding to structural elements of the
2449: document</strong> are those which linked to each of the elements (base or
2450: structured) of the logical structure of the document. Such a box contains all
2451: the contents of the element to which it corresponds (there is an exception:
2452: see <a href="#sectc4220">rules <tt>VertOverflow</tt> and
2453: <tt>HorizOverflow</tt></a>). These boxes form a tree-like structure,
2454: identical to that of the structural elements to which they correspond. This
2455: tree expresses the inclusion relationships between the boxes: a box includes
2456: all the boxes of its subtree. On the other hand, there are no predefined
2457: rules for the relative positions of the included boxes. If they are at the
2458: same level, they can overlap, be contiguous, or be disjoint. The rules
2459: expressed in the generic presentation specify their relative positions.</p>
1.30 cvs 2460:
2461: <p><strong>Presentation boxes</strong> represent elements which are not found
1.37 cvs 2462: in the logical structure of the document but which are added to meet the
2463: needs of presentation. These boxes are linked to the elements of the logical
1.30 cvs 2464: structure that are best suited to bringing them out. For example, they are
2465: used to add the character string ``Summary:'' before the summary in the
2466: presentation of a report or to represent the fraction bar in a formula, or
1.37 cvs 2467: also to make the title of a field in a form appear. These elements have no
1.30 cvs 2468: role in the logical structure of the document: the presence of a Summary
2469: element in the document does not require the creation of another structural
1.37 cvs 2470: object to hold the word ``Summary''. Similarly, if a Fraction element
2471: contains both a Numerator element and a Denominator element, the fraction bar
2472: has no purpose structurally. On the other hand, these elements of the
2473: presentation are important for the reader of the reproduced document or for
2474: the user of an editor. This is why they must appear in the document's image.
2475: It is the generic presentation which specifies the presentation boxes to add
2476: by indicating their content (a base element for which the value is specified)
2477: and the position that they must take in the tree of boxes. During editing,
2478: these boxes cannot be modified by the user.</p>
2479:
2480: <p><strong>Page layout boxes</strong> are boxes created implicitly by the
2481: page layout rules. These rules indicate how the contents of a structured
2482: element must be broken into lines and pages. In contrast to presentation
2483: boxes, these line and page boxes do not depend on the logical structure of
2484: the document, but rather on the physical constraints of the output devices:
2485: character size, height and width of the window on the screen or of the sheet
2486: of paper.</p>
1.18 cvs 2487: </div>
1.1 cvs 2488:
1.18 cvs 2489: <div class="subsection">
1.37 cvs 2490: <h3><a name="sectc413" id="sectc413">Views and visibility</a></h3>
1.1 cvs 2491:
1.30 cvs 2492: <p>One of the operations that one might wish to perform on a document is to
1.37 cvs 2493: view it is different ways. For this reason, it is possible to define several
1.18 cvs 2494: <em>views</em> for the same document, or better yet, for all documents of the
1.37 cvs 2495: same class. A view is not a different presentation of the document, but
1.1 cvs 2496: rather a filter which only allows the display of certain parts of the
1.37 cvs 2497: document. For example, it might be desirable to see only the titles of
1.1 cvs 2498: chapters and sections in order to be able to move rapidly through the
1.37 cvs 2499: document. Such a view could be called a ``table of contents''. It might also
1.1 cvs 2500: be desirable to see only the mathematical formulas of a document in order to
1.37 cvs 2501: avoid being distracted by the non-mathematical aspects of the document. A
1.18 cvs 2502: ``mathematics'' view could provide this service.</p>
1.30 cvs 2503:
2504: <p>Views, like presentation, are based on the generic logical structure. Each
1.1 cvs 2505: document class, and each generic presentation, can be provided with views
1.37 cvs 2506: which are particularly useful for that class or presentation. For each view,
1.18 cvs 2507: the <em>visibility</em> of elements is defined, indicated whether or not the
1.37 cvs 2508: elements must be presented to the user. The visibility is calculated as a
1.1 cvs 2509: function of the type of the elements or their hierarchical position in the
1.37 cvs 2510: structure of the document. Thus, for a table of contents, all the ``Chapter
2511: Title'' and ``Section Title'' elements are made visible. However, the
1.1 cvs 2512: hierarchical level could be used to make the section titles invisible below a
1.37 cvs 2513: certain threshold level. By varying this threshold, the granularity of the
2514: view can be varied. In the ``mathematics'' view, only Formula elements would
1.18 cvs 2515: be made visible, no matter what their hierarchical level.</p>
1.30 cvs 2516:
2517: <p>Because views are especially useful for producing a synthetic image of the
1.1 cvs 2518: document, it is necessary to adapt the presentation of the elements to the
1.37 cvs 2519: view in which they appear. For example, it is inappropriate to have a page
2520: break before every chapter title in the table of contents. Thus, generic
1.1 cvs 2521: presentations take into account the possible views and permit each element
1.18 cvs 2522: type's presentation to vary according the view in which its image appears.</p>
2523: </div>
1.1 cvs 2524:
1.18 cvs 2525: <div class="subsection">
1.37 cvs 2526: <h3><a name="sectc414" id="sectc414">Pages</a></h3>
1.1 cvs 2527:
1.30 cvs 2528: <p>Presentation schemas can be defined which display the document as a long
1.37 cvs 2529: scroll, without page breaks. This type of schema is particularly well-suited
1.1 cvs 2530: to the initial phase of work on a document, where jumps from page to page
1.37 cvs 2531: would hinder composing and reading the document on a screen. But, once the
2532: document is written, it may be desirable to display the document on the
2533: screen in the same manner in which it will be printed. So, the presentation
2534: schema must define pages.</p>
2535:
2536: <p>The P language permits the specification of the dimensions of pages as
2537: well as their composition. It is possible to generate running titles, page
2538: numbers, zones at the bottom of the page for notes, etc. The editor follows
1.30 cvs 2539: this model and inserts page break marks in the document which are used during
2540: printing, insuring that the pages on paper are the same as on the screen.</p>
2541:
2542: <p>Once a document has been edited with a presentation schema defining pages,
1.37 cvs 2543: it contains page marks. But it is always possible to edit the document using
2544: a schema without pages. In this case, the page marks are simply ignored by
2545: the editor. They are considered again as soon as a schema with pages is used.
1.18 cvs 2546: Thus, the user is free to choose between schemas with and without pages.</p>
1.30 cvs 2547:
2548: <p>Thot treats the page break, rather than the page itself, as a box. This
2549: page break box contains all the elements of one page's footer, a rule marking
1.37 cvs 2550: the edge of this page, and all the elements of the next page's header. The
2551: elements of the header and footer can be running titles, page number, notes,
2552: etc. All these elements, as well as their content and graphical appearance,
2553: are defined by the generic presentation.</p>
1.18 cvs 2554: </div>
1.1 cvs 2555:
1.18 cvs 2556: <div class="subsection">
1.37 cvs 2557: <h3><a name="sectc415" id="sectc415">Numbering</a></h3>
1.1 cvs 2558:
1.30 cvs 2559: <p>Many elements are numbered in documents: pages, chapters, sections,
2560: formulas, theorems, notes, figures, bibliographic references, exercises,
1.37 cvs 2561: examples, lemmas, etc. Because Thot has a notion of logical structure, all of
1.30 cvs 2562: these numbers (with the exception of pages) are redundant with information
1.37 cvs 2563: implicit in the logical structure of the document. Such numbers are simply a
2564: way to make the structure of the document more visible. So, they are part of
1.30 cvs 2565: the document's presentation and are calculated by the editor from the logical
1.37 cvs 2566: structure. The structure does not contain numbers as such; it only defines
1.1 cvs 2567: relative structural positions between elements, which serve as ordering
1.18 cvs 2568: relations on these elements.</p>
1.30 cvs 2569:
2570: <p>If the structure schema defines the body of a document as a sequence of at
1.18 cvs 2571: least two chapters:</p>
2572: <pre>Body = LIST [2..*] OF Chapter;</pre>
1.30 cvs 2573:
2574: <p>the sequence defined by the list constructor is ordered and each chapter
1.37 cvs 2575: can be assigned a number based on its rank in the Body list. Therefore, all
2576: elements contained in lists a the structure of a document can be numbered,
2577: but they are not the only ones. The tree structure induced by the aggregate,
1.18 cvs 2578: list, and choice constructors (excluding references) defines a total order on
1.37 cvs 2579: the elements of the document's primary structure. So, it is possible to
1.18 cvs 2580: define a numbering which uses this order, filtering elements according to
2581: their type so that only certain element types are taken into account in the
1.37 cvs 2582: numbering. In this way, it possible to number all the theorems and lemmas of
1.18 cvs 2583: a chapter in the same sequence of numbers, even when they are not part of the
2584: same list constructor and appear at different levels of the document's tree.
2585: By changing the filter, they can be numbered separately: one sequence of
2586: numbers for theorems, another for the lemmas.</p>
1.30 cvs 2587:
2588: <p>Since they are calculated from the document's logical structure and only
2589: for the needs of the presentation, numbers are presentation elements,
2590: described by presentation boxes, just like the fraction bar or the word
1.37 cvs 2591: ``Summary''. Nevertheless, numbers differ from these other boxes because
2592: their content varies from instance to instance, even though they are of the
2593: same type, whereas all fraction bars are horizontal lines and the same word
1.30 cvs 2594: ``Summary'' appears at the head of every document's summary.</p>
1.18 cvs 2595: </div>
1.1 cvs 2596:
1.18 cvs 2597: <div class="subsection">
1.37 cvs 2598: <h3><a name="sectc416" id="sectc416">Presentation properties</a></h3>
1.1 cvs 2599:
1.34 cvs 2600: <p>The principal properties which determine document presentation are the
1.18 cvs 2601: <em>positions</em> and <em>dimensions</em> of boxes, the <em>font</em>, the
2602: <em>style</em>, the <em>size</em>, the <em>underlining</em> and the
1.37 cvs 2603: <em>color</em> of their content. From these properties, and some others of
1.34 cvs 2604: less importance, it is possible to represent the usual typographic properties
1.37 cvs 2605: for the textual parts of the document. These same properties can be used to
1.1 cvs 2606: describe the geometry of the non-textual elements, even though they are
1.18 cvs 2607: two-dimensional elements unlike the text, which is linear.</p>
1.30 cvs 2608:
1.37 cvs 2609: <p>As we have already seen, the positions of the boxes always respect the
1.30 cvs 2610: rule of enclosure: a box in the tree encloses all the boxes of the next lower
1.37 cvs 2611: level which are attached to it. The positional properties permit the
1.30 cvs 2612: specification of the position of each box in relation to the enclosing box or
1.37 cvs 2613: to its sibling boxes (boxes directly attached to the same enclosing box in
2614: the tree of boxes).</p>
1.30 cvs 2615:
1.37 cvs 2616: <p>The presentation properties also provide control over the dimensions of
2617: the boxes. The dimensions of a box can depend either on its content or on its
1.1 cvs 2618: context (its sibling boxes and the enclosing box). Each dimension (height or
1.18 cvs 2619: width) can be defined independently of the other.</p>
1.30 cvs 2620:
1.34 cvs 2621: <p>Because of the position and dimension properties, it is possible to do the
1.1 cvs 2622: same things that are normally done in typography by changing margins, line
1.37 cvs 2623: lengths, and vertical or horizontal skips. This approach can also align or
1.18 cvs 2624: center elements and groups of elements.</p>
1.30 cvs 2625:
1.34 cvs 2626: <p>In contrast to the position and dimension properties, the font, style,
1.30 cvs 2627: size, underlining, and color do not concern the box itself (the rectangle
1.37 cvs 2628: delimiting the element), but its content. These properties indicate the
2629: typographic attributes which must be applied to the text contained in the
2630: box, and by extension, to all base elements.</p>
1.30 cvs 2631:
1.34 cvs 2632: <p>For text, the font property is used to change the family of characters
1.1 cvs 2633: (Times, Helvetica, Courier, etc.); the style is used to obtain italic or
1.37 cvs 2634: roman, bold or light characters; the size determines the point size of the
1.1 cvs 2635: characters; underlining defines the type and thickness of the lines drawn
1.18 cvs 2636: above, below, or through the characters.</p>
1.30 cvs 2637:
1.34 cvs 2638: <p>For graphics, the line style property can be either solid, dotted, or
2639: dashed; the line thickness property controls the width of the lines; the fill
2640: pattern property determines how closed geometric figures must be filled.</p>
1.30 cvs 2641:
1.34 cvs 2642: <p>While some of the properties which determine the appearance of a box's
1.1 cvs 2643: contents make sense only for one content type (text or graphic), other
1.34 cvs 2644: properties apply to all content types: these are the color properties. These
1.18 cvs 2645: indicate the color of lines and the background color.</p>
2646: </div>
2647: </div>
1.1 cvs 2648:
1.18 cvs 2649: <div class="section">
1.37 cvs 2650: <h2><a name="sectb42" id="sectb42">Presentation description language</a></h2>
1.30 cvs 2651:
1.34 cvs 2652: <p>A generic presentation defines the values of presentation properties (or
1.37 cvs 2653: the way to calculate those values) for a generic structure, or more
2654: precisely, for all the element types and all the global and local attributes
2655: defined in that generic structure. This definition of the presentation
2656: properties is made with the P language. A program written in this language,
2657: that is a generic presentation expressed in P, is call a <em>presentation
2658: schema</em>. This section describes the syntax and semantics of the language,
2659: using the same <a href="#sectc321">meta-language</a> as was used for the
2660: definition of the S language.</p>
2661:
2662: <p>Recall that it is possible to write many different presentation schemas
2663: for the same class of documents or objects. This allows users to choose for a
2664: document the graphical appearance which best suits their type of work or
1.18 cvs 2665: their personal taste.</p>
1.1 cvs 2666:
1.18 cvs 2667: <div class="subsection">
1.37 cvs 2668: <h3><a name="sectc421" id="sectc421">The organization of a presentation
2669: schema</a></h3>
1.1 cvs 2670:
1.30 cvs 2671: <p>A presentation schema begins with the word <tt>PRESENTATION</tt> and ends
1.37 cvs 2672: with the word <tt>END</tt>. The word <tt>PRESENTATION</tt> is followed by the
2673: name of the generic structure to which the presentation will be applied. This
1.30 cvs 2674: name must be the same as that which follows the keyword <tt>STRUCTURE</tt> in
2675: the structure schema associated with the presentation schema.</p>
2676:
1.37 cvs 2677: <p>After this declaration of the name of the structure, the following
2678: sections appear (in order):</p>
1.18 cvs 2679: <ul>
1.37 cvs 2680: <li>Declarations of
1.30 cvs 2681: <ul>
2682: <li>all views,</li>
2683: <li>printed views,</li>
2684: <li>counters,</li>
2685: <li>presentation constants,</li>
2686: <li>variables,</li>
2687: </ul>
2688: </li>
2689: <li>default presentation rules,</li>
2690: <li>presentation box and page layout box definitions,</li>
2691: <li>presentation rules for structured elements,</li>
2692: <li>presentation rules for attributes,</li>
2693: <li>rules for transmitting values to attributes of included documents.</li>
1.18 cvs 2694: </ul>
1.30 cvs 2695:
2696: <p>Each of these sections is introduced by a keyword which is followed by a
1.37 cvs 2697: sequence of declarations. Every section is optional.</p>
1.18 cvs 2698: <pre> SchemaPres ='PRESENTATION' ElemID ';'
1.1 cvs 2699: [ 'VIEWS' ViewSeq ]
2700: [ 'PRINT' PrintViewSeq ]
2701: [ 'COUNTERS' CounterSeq ]
2702: [ 'CONST' ConstSeq ]
2703: [ 'VAR' VarSeq ]
2704: [ 'DEFAULT' ViewRuleSeq ]
2705: [ 'BOXES' BoxSeq ]
2706: [ 'RULES' PresentSeq ]
2707: [ 'ATTRIBUTES' PresAttrSeq ]
2708: [ 'TRANSMIT' TransmitSeq ]
2709: 'END' .
1.18 cvs 2710: ElemID = NAME .</pre>
2711: </div>
1.1 cvs 2712:
1.18 cvs 2713: <div class="subsection">
1.37 cvs 2714: <h3><a name="sectc422" id="sectc422">Views</a></h3>
1.1 cvs 2715:
1.37 cvs 2716: <p>Each of the possible views must be declared in the presentation schema. As
2717: has <a href="#views">already been described</a>, the presentation rules for
2718: an element type can vary according to the view in which the element appears.
2719: The name of the view is used to designate the view to which the presentation
2720: rules apply (see the <a href="#inkeyword"><tt>IN</tt> instruction</a>). The
1.1 cvs 2721: definition of the view's contents are dispersed throughout the presentation
1.37 cvs 2722: rules attached to the different element types and attributes. The
1.18 cvs 2723: <tt>VIEWS</tt> section is simply a sequence of view names separated by commas
2724: and terminated by a semi-colon.</p>
1.30 cvs 2725:
2726: <p>One of the view names (and only one) can be followed by the keyword
1.37 cvs 2727: <tt>EXPORT</tt>. This keyword identifies the view which presents the members
2728: of the document class in <a href="#sectc3213">skeleton form</a>. The
2729: graphical appearance and the content of this view is defined just as with
1.18 cvs 2730: other views, but it is useless to specify presentation rules concerning this
2731: view for the elements which are not loaded in the skeleton form.</p>
1.30 cvs 2732:
2733: <p>It is not necessary to declare any views; in this case there is a single
1.37 cvs 2734: unnamed view. If many views are declared, the first view listed is considered
2735: the principal view. The principal view is the one to which all rules that are
1.18 cvs 2736: not preceded by an indication of a view will apply (see the <a
2737: href="#inkeyword">instruction <tt>IN</tt></a>).</p>
1.30 cvs 2738:
2739: <p>The principal view is the the one which the editor presents on the screen
1.37 cvs 2740: when the user asks to create or edit a document. Thus, it makes sense to put
2741: the most frequently used view at the head of the list. But if the structure
1.18 cvs 2742: schema contains <a href="#sectc3213">skeleton elements</a> and is loaded in
2743: its skeleton form, the view whose name is followed by the keyword
2744: <tt>EXPORT</tt> will be opened and no other views can be opened.</p>
2745: <pre> 'VIEWS' ViewSeq
1.1 cvs 2746: ViewSeq = ViewDeclaration
1.30 cvs 2747: < ',' ViewDeclaration > ';' .
1.1 cvs 2748: ViewDeclaration = ViewID [ 'EXPORT' ] .
1.18 cvs 2749: ViewID = NAME .</pre>
1.30 cvs 2750:
1.18 cvs 2751: <blockquote class="example">
1.30 cvs 2752: <p><strong>Example:</strong></p>
2753:
2754: <p>When editing a report, it might be useful have views of the table of
1.37 cvs 2755: contents and of the mathematical formulas, in addition to the principal
2756: view which shows the document in its entirety. To achieve this, a
2757: presentation schema for the Report class would have the following
2758: <tt>VIEWS</tt> section:</p>
1.30 cvs 2759: <pre>VIEWS
1.18 cvs 2760: Full_text, Table_of_contents, Formulas;</pre>
1.30 cvs 2761:
2762: <p>The contents of these views are specified in the presentation rules of
2763: the schema.</p>
1.18 cvs 2764: </blockquote>
2765: </div>
1.1 cvs 2766:
1.18 cvs 2767: <div class="subsection">
1.37 cvs 2768: <h3><a name="sectc423" id="sectc423">Print Views</a></h3>
1.1 cvs 2769:
1.37 cvs 2770: <p>When editing a document, each view specified by the <tt>VIEWS</tt>
2771: instruction is presented in a different window.</p>
1.30 cvs 2772:
2773: <p>When printing a document, it is possible to print any number of views,
1.37 cvs 2774: chosen from among all the views which the editor can display. Print views, as
2775: well as the order in which they must be printed, are indicated by the
2776: <tt>PRINT</tt> instruction. It appears after the <tt>VIEWS</tt> instruction
2777: and is formed of the keyword <tt>PRINT</tt> followed by the ordered list of
2778: print view names. The print view names are separated by commas and followed
2779: by a semi-colon. A print view name is a view name declared in the
2780: <tt>VIEWS</tt> instruction.</p>
1.18 cvs 2781: <pre> 'PRINT' PrintViewSeq
1.30 cvs 2782: PrintViewSeq = PrintView < ',' PrintView > ';' .
1.37 cvs 2783: PrintView = ViewID .</pre>
1.30 cvs 2784:
2785: <p>If the <tt>PRINT</tt> instruction is absent, the printing program will
2786: print only the principal view (the first view specified by the <tt>VIEWS</tt>
1.18 cvs 2787: instruction or the single, unnamed view when there is no <tt>VIEWS</tt>
2788: instruction).</p>
1.30 cvs 2789:
1.18 cvs 2790: <blockquote class="example">
1.30 cvs 2791: <p><strong>Example:</strong></p>
2792:
2793: <p>Consider a Report presentation using the view declarations from the
1.37 cvs 2794: preceding example. Suppose we want to print the full text and table of
1.30 cvs 2795: contents views, but not the Formulas view, which is only useful when
1.37 cvs 2796: editing. A sensible printing order would be to print the full text followed
2797: by the table of contents. To obtain this result when printing, the
2798: presentation schema would say:</p>
1.30 cvs 2799: <pre>PRINT
1.37 cvs 2800: Full_text, Table_of_contents;</pre>
1.18 cvs 2801: </blockquote>
2802: </div>
2803:
2804: <div class="subsection">
1.37 cvs 2805: <h3><a name="sectc424" id="sectc424">Counters</a></h3>
1.18 cvs 2806:
1.30 cvs 2807: <p>A presentation has a <em>counter</em> for each type of number in the
1.37 cvs 2808: presentation. All counters, and therefore all types of numbers, used in the
1.18 cvs 2809: schema must be declared after the <tt>COUNTERS</tt> keyword.</p>
1.30 cvs 2810:
2811: <p>Each counter declaration is composed of a name identifying the counter
1.1 cvs 2812: followed by a colon and the counting function to be applied to the counter.
1.18 cvs 2813: The counter declaration ends with a semi-colon.</p>
1.30 cvs 2814:
2815: <p>The counting function indicates how the counter values will be calculated.
1.37 cvs 2816: Three types of counting functions are available. The first type is used to
1.16 cvs 2817: count the elements of a list or aggregate: it assigns to the counter the rank
1.37 cvs 2818: of the element in the list or aggregate. More precisely, the function</p>
1.18 cvs 2819: <pre>RANK OF ElemID [ LevelAsc ] [ INIT AttrID ]
2820: [ 'REINIT' AttrID ]</pre>
1.30 cvs 2821:
2822: <p>indicates that when an element creates, by a creation rule (see the <a
1.18 cvs 2823: href="#sectc4232"><tt>Create</tt> instructions</a>), a presentation box
1.37 cvs 2824: containing the counter value, this value is the rank of the creating element,
1.18 cvs 2825: if it is of type <tt>ElemID</tt>, otherwise the rank of the first element of
2826: type <tt>ElemID</tt> which encloses the creating element in the logical
2827: structure of the document.</p>
1.30 cvs 2828:
2829: <p>The type name can be preceded by a star in the special case where the
1.18 cvs 2830: structure schema defines an element of whose <tt>ElemID</tt> is the same as
2831: that of an <a href="#sectd3284">inclusion</a> without expansion or with
1.37 cvs 2832: partial expansion. To resolve this ambiguity, the <tt>ElemID</tt> alone
1.18 cvs 2833: refers to the type defined in the structure schema while the <tt>ElemID</tt>
2834: preceded by a star refers to the included type.</p>
1.30 cvs 2835:
1.37 cvs 2836: <p>The type name <tt>ElemID</tt> can be followed by an integer. That number
2837: represents the relative level, among the ancestors of the creating element,
2838: of the element whose rank is asked. If that relative level <i>n</i> is
2839: unsigned, the <i>n</i><sup>th</sup> element of type <tt>ElemID</tt>
2840: encountered when travelling the logical structure from the root to the
2841: creating element is taken into account. If the relative level is negative,
2842: the logical structure is travelled in the other direction, from the creating
2843: element to the root.</p>
1.30 cvs 2844:
1.37 cvs 2845: <p>The function can end with the keyword <tt>INIT</tt> followed by the name
2846: of a numeric attribute (and only a numeric attribute). Then, the rank of the
1.30 cvs 2847: first element of the list or aggregate is considered to be the value of this
1.1 cvs 2848: attribute, rather than the default value of 1, and the rank of the other
1.37 cvs 2849: elements is shifted accordingly. The attribute which determines the initial
1.18 cvs 2850: value is searched on the element itself and on its ancestors.</p>
1.30 cvs 2851:
2852: <p>The function can end with the keyword <tt>REINIT</tt> followed by the name
1.37 cvs 2853: of a numeric attribute (and only a numeric attribute). Then, if an element to
1.30 cvs 2854: be counted has this attribute, the counter value for this element is the
1.1 cvs 2855: attribute value and the following elements are numbered starting from this
1.18 cvs 2856: value.</p>
1.30 cvs 2857:
2858: <p>When the <tt>RANK</tt> function is written</p>
1.18 cvs 2859: <pre>RANK OF Page [ ViewID ] [ INIT AttrID ]</pre>
1.30 cvs 2860:
2861: <p>(<tt>Page</tt>is a keyword of the P language), the counter takes as its
2862: value the number of the page on which the element which creates the
1.37 cvs 2863: presentation box containing the number appears. This is done as if the pages
2864: of the document form a list for each view. The counter only takes into
1.30 cvs 2865: account the pages of the relevant view, that is the view displaying the
1.37 cvs 2866: presentation box whose contents take the value of the number. However, if the
2867: keyword <tt>Page</tt> is followed by the name of a view (between
2868: parentheses), it is the pages of that view that are taken into account. As in
2869: the preceding form, the <tt>RANK</tt> function applied to pages can end with
2870: the <tt>INIT</tt> keyword followed by the name of a numeric attribute which
2871: sets the value of the first page's number. This attribute must be a local
1.30 cvs 2872: attribute of the document itself, and not of one of its components.</p>
2873:
2874: <p>The second counting function is used to count the occurrences of a certain
1.37 cvs 2875: element type in a specified context. The instruction</p>
1.18 cvs 2876: <pre>SET n ON Type1 ADD m ON Type2 [ INIT AttrID ]</pre>
1.30 cvs 2877:
2878: <p>says that when the document is traversed from beginning to end (in the
2879: order induced by the logical structure), the counter is assigned the value
1.18 cvs 2880: <tt>n</tt> each time an element of type <tt>Type1</tt> is encountered, no
2881: matter what the current value of the counter, and the value <tt>m</tt> is
2882: added to the current value of the counter each time an element of type
2883: <tt>Type2</tt> is encountered.</p>
1.30 cvs 2884:
2885: <p>As with the <tt>RANK</tt> function, the type names can be preceded by a
2886: star to resolve the ambiguity of included elements.</p>
2887:
1.37 cvs 2888: <p>If the function ends with the keyword <tt>INIT</tt> followed by the name
2889: of an attribute and if the document possesses this attribute, the value of
2890: this attribute is used in place of <tt>n</tt>. The attribute must be numeric.
2891: It is searched on the element itself and on its ancestors.</p>
1.30 cvs 2892:
2893: <p>This function can also be used with the <tt>Page</tt> keyword in the place
1.37 cvs 2894: of <tt>Type1</tt> or <tt>Type2</tt>. In the first case, the counter is
1.18 cvs 2895: reinitialized on each page with the value <tt>n</tt>, while in the second
1.37 cvs 2896: case, it is incremented by <tt>m</tt> on each page. As with the preceding
1.18 cvs 2897: counting function, the word <tt>Page</tt> can be followed by a name between
1.37 cvs 2898: parentheses. In this case, the name specifies a view whose pages are taken
1.18 cvs 2899: into account.</p>
1.30 cvs 2900:
2901: <p>The definition of a counter can contain several <tt>SET</tt> functions and
1.37 cvs 2902: several <tt>ADD</tt> functions, each with a different value. The total number
1.18 cvs 2903: of counting functions must not be greater than 6.</p>
1.30 cvs 2904:
1.37 cvs 2905: <p>The third counting function is used to count the elements of a certain
2906: type encountered when travelling from the creating element to the root of the
2907: logical structure. The creating element is included if it is of that type.
1.18 cvs 2908: That function is written</p>
2909: <pre>RLEVEL OF Type</pre>
1.30 cvs 2910:
2911: <p>where <tt>Type</tt> represents the type of the elements to be counted.</p>
2912:
2913: <p>The formal definition of counter declarations is:</p>
1.18 cvs 2914: <pre> 'COUNTERS' CounterSeq
1.30 cvs 2915: CounterSeq = Counter < Counter > .
1.1 cvs 2916: Counter = CounterID ':' CounterFunc ';' .
2917: CounterID = NAME .
2918: CounterFunc = 'RANK' 'OF' TypeOrPage [ SLevelAsc ]
1.16 cvs 2919: [ 'INIT' AttrID ] [ 'REINIT' AttrID ] /
1.30 cvs 2920: SetFunction < SetFunction >
2921: AddFunction < AddFunction >
1.16 cvs 2922: [ 'INIT' AttrID ] /
2923: 'RLEVEL' 'OF' ElemID .
1.1 cvs 2924: SLevelAsc = [ '-' ] LevelAsc .
2925: LevelAsc = NUMBER .
2926: SetFunction = 'SET' CounterValue 'ON' TypeOrPage .
2927: AddFunction = 'ADD' CounterValue 'ON' TypeOrPage .
2928: TypeOrPage = 'Page' [ '(' ViewID ')' ] /
1.16 cvs 2929: [ '*' ] ElemID .
1.18 cvs 2930: CounterValue = NUMBER .</pre>
1.30 cvs 2931:
1.18 cvs 2932: <blockquote class="example">
1.30 cvs 2933: <p><strong>Example:</strong></p>
2934:
2935: <p>If the body of a chapter is defined as a sequence of sections in the
2936: structure schema:</p>
2937: <pre>Chapter_body = LIST OF (Section =
1.1 cvs 2938: BEGIN
2939: Section_Title = Text;
2940: Section_Body = Paragraphs;
2941: END
1.18 cvs 2942: );</pre>
1.30 cvs 2943:
2944: <p>the section counter is declared:</p>
2945: <pre>SectionCtr : RANK OF Section;</pre>
2946:
2947: <p>and the display of the section number before the section title is
2948: obtained by a <a href="#sectc4232"><tt>CreateBefore</tt> rule</a> attached
2949: the <tt>Section_Title</tt> type, which creates a presentation box whose
2950: content is the value of the <tt>SectionCtr</tt> counter (see the <a
2951: href="#sectc4231"><tt>Content</tt> instruction</a>).</p>
2952:
2953: <p>In order to number the formulas separately within each chapter, the
2954: formula counter is declared:</p>
2955: <pre>FormulaCtr : SET 0 ON Chapter ADD 1 ON Formula;</pre>
2956:
1.37 cvs 2957: <p>and the display of the formula number in the right margin, alongside
2958: each formula, is obtained by a <tt>CreateAfter</tt> instruction attached to
2959: the <tt>Formula</tt> type, which creates a presentation box whose content
2960: is the value of the <tt>FormulaCtr</tt> counter.</p>
1.30 cvs 2961:
2962: <p>To number the page chapter by chapter, with the first page of each
2963: chapter having the number 1, the counter definition would be</p>
2964: <pre>ChapterPageCtr : SET 0 ON Chapter ADD 1 ON Page;</pre>
2965:
2966: <p>If there is also a chapter counter</p>
2967: <pre>ChapterCtr : RANK OF Chapter;</pre>
2968:
1.37 cvs 2969: <p>the <a href="#sectc4231">content</a> of a presentation box created at
2970: the top of each page could be defined as:</p>
1.30 cvs 2971: <pre>Content : (VALUE(ChapterCtr, URoman) TEXT '-'
1.18 cvs 2972: VALUE(ChapterPageCtr, Arabic));</pre>
1.30 cvs 2973:
2974: <p>Thus, the presentation box contains the number of the chapter in
2975: upper-case roman numerals followed by a hyphen and the number of the page
2976: within the chapter in arabic numerals.</p>
1.18 cvs 2977: </blockquote>
1.30 cvs 2978:
1.18 cvs 2979: <blockquote class="example">
1.30 cvs 2980: <p><strong>Example:</strong></p>
2981:
1.37 cvs 2982: <p>To count tables and figures together in a document of the chapter type,
2983: a counter could be defined using:</p>
1.30 cvs 2984: <pre>CommonCtr : SET 0 ON Chapter ADD 1 ON Table
1.18 cvs 2985: ADD 1 ON Figure;</pre>
2986: </blockquote>
2987: </div>
1.1 cvs 2988:
1.18 cvs 2989: <div class="subsection">
1.37 cvs 2990: <h3><a name="sectc425" id="sectc425">Presentation constants</a></h3>
1.1 cvs 2991:
1.30 cvs 2992: <p>Presentation constants are used in the definition of the content of
1.37 cvs 2993: presentation boxes. This content is used in <a href="#sectc426">variable
2994: definitions</a> and in the <a href="#sectc4231"><tt>Content</tt> rule</a>.
2995: The only presentation constants which can be used are character strings,
1.2 cvs 2996: mathematical symbols, graphical elements, and pictures, that is to say, base
1.18 cvs 2997: elements.</p>
1.30 cvs 2998:
2999: <p>Constants can be defined directly in the variables or presentation boxes
1.37 cvs 3000: (<tt>Content</tt> rule) which use them. But it is only necessary them to
1.1 cvs 3001: declare once, in the constant declaration section, even though they are used
1.37 cvs 3002: in many variables or boxes. Thus, each declared constant has a name, which
1.1 cvs 3003: allows it to be designated whenever it is used, a type (one of the four base
3004: types) and a value (a character string or a single character for mathematical
1.18 cvs 3005: symbols and graphical elements).</p>
1.30 cvs 3006:
1.37 cvs 3007: <p>The constant declarations appear after the keyword <tt>CONST</tt>. Each
3008: declaration is composed of the name of the constant, an equals sign, a
3009: keyword representing its type (<tt>Text</tt>, <tt>Symbol</tt>,
3010: <tt>Graphics</tt> or <tt>Picture</tt>) and the string representing its value.
3011: A semi-colon terminates each declaration.</p>
1.30 cvs 3012:
3013: <p>In the case of a character string, the keyword <tt>Text</tt> can be
1.41 vatton 3014: followed by the name of an script (for example, <tt>Greek</tt> or
1.37 cvs 3015: <tt>Latin</tt>) in which the constant's text should be expressed. If the
1.43 quint 3016: script name is absent, the Latin script is used. When the script name is
3017: present, only the first letter of the script name is interpreted. Thus, the
3018: words <tt>Greek</tt> and <tt>Grec</tt> designate the same script. In current
3019: versions of Thot, only the Greek and Latin scripts are available.</p>
1.18 cvs 3020: <pre> 'CONST' ConstSeq
1.30 cvs 3021: ConstSeq = Const < Const > .
1.1 cvs 3022: Const = ConstID '=' ConstType ConstValue ';' .
3023: ConstID = NAME .
1.41 vatton 3024: ConstType ='Text' [ Script ] / 'Symbol' /
1.1 cvs 3025: 'Graphics' / 'Picture' .
3026: ConstValue = STRING .
1.41 vatton 3027: Script = NAME .</pre>
1.30 cvs 3028:
1.41 vatton 3029: <p>For character strings in the Latin script (ISO Latin-1 character set),
1.1 cvs 3030: characters having codes higher than 127 (decimal) are represented by their
1.18 cvs 3031: code in octal.</p>
1.30 cvs 3032:
3033: <p>In the case of a symbol or graphical element, the value only contains a
1.37 cvs 3034: single character, between apostrophes, which indicates the form of the
3035: element which must be drawn in the box whose content is the constant. The
3036: symbol or graphical element takes the dimensions of the box, which are
3037: determined by the <tt>Height</tt> and <tt>Width</tt> rules. See <a
3038: href="#sectb72">table of codes</a> for the symbols and graphical elements.</p>
1.30 cvs 3039:
1.18 cvs 3040: <blockquote class="example">
1.30 cvs 3041: <p><strong>Example:</strong></p>
3042:
3043: <p>The constants ``Summary:'' and fraction bar, which were described
3044: earlier, are declared:</p>
3045: <pre>CONST
1.1 cvs 3046: SummaryConst = Text 'Summary:';
1.18 cvs 3047: Bar = Graphics 'h';</pre>
3048: </blockquote>
3049: </div>
1.1 cvs 3050:
1.18 cvs 3051: <div class="subsection">
1.37 cvs 3052: <h3><a name="sectc426" id="sectc426">Variables</a></h3>
1.1 cvs 3053:
1.37 cvs 3054: <p>Variables permit the definition of computed content for presentation
3055: boxes. A variable is associated with a presentation box by a <tt>Content</tt>
3056: rule; but before being used in a <tt>Content</tt> rule, a variable can be
3057: defined in the <tt>VAR</tt> section. It is also possible to define a variable
3058: at the time of its use in a <tt>Content</tt> rule, as can be done with a
1.30 cvs 3059: constant.</p>
3060:
3061: <p>A variable has a name and a value which is a character string resulting
1.37 cvs 3062: from the concatenation of the values of a sequence of functions. Each
1.30 cvs 3063: variable declaration is composed of the variable name followed by a colon and
1.37 cvs 3064: the sequence of functions which produces its value, separated by spaces. Each
1.18 cvs 3065: declaration is terminated by a semi-colon.</p>
3066: <pre> 'VAR' VarSeq
1.30 cvs 3067: VarSeq = Variable < Variable > .
1.1 cvs 3068: Variable = VarID ':' FunctionSeq ';' .
3069: VarID = NAME .
1.30 cvs 3070: FunctionSeq = Function < Function > .</pre>
3071:
1.37 cvs 3072: <p>Several functions are available. The first two return, in the form of a
3073: character string, the current date. <tt>DATE</tt> returns the date in
1.18 cvs 3074: English, while <tt>FDATE</tt> returns the date in french.</p>
1.30 cvs 3075:
3076: <p>Two other functions, <tt>DocName</tt> and <tt>DirName</tt>, return the
1.18 cvs 3077: document name and the directory where the document is stored.</p>
1.30 cvs 3078:
1.38 cvs 3079: <p>Function <tt>ElemName</tt> returns the name of the element which created
1.30 cvs 3080: the presentation box whose contents are the variable.</p>
3081:
1.38 cvs 3082: <p>Function <tt>AttributeName</tt> returns the name 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:
3086: <p>Function <tt>AttributeValue</tt> returns the value of the attribute which
3087: created the presentation box whose contents are the variable. The
3088: presentation box must be created by an attribute.</p>
3089:
1.30 cvs 3090: <p>Another function simply returns the value of a presentation constant. For
3091: any constant declared in the <tt>CONST</tt> section, it is sufficient to give
1.37 cvs 3092: the name of the constant. Otherwise, the type and value of the constant must
1.30 cvs 3093: be given, using the same form as in a <a href="#sectc425">constant
1.18 cvs 3094: declaration</a>. If the constant is not of type text, (types <tt>Symbol</tt>,
3095: <tt>Graphics</tt> or <tt>Picture</tt>), it must be alone in the variable
3096: definition; only constants of type <tt>Text</tt> can be mixed with other
3097: functions.</p>
1.30 cvs 3098:
3099: <p>It is also possible to obtain the value of an attribute, simply by
1.37 cvs 3100: mentioning the attribute's name. The value of this function is the value of
1.30 cvs 3101: the attribute for the element which created the presentation box whose
1.37 cvs 3102: contents are the variable. If the creating element does not have the
3103: indicated attribute, the value is an empty string. In the case of a numeric
1.30 cvs 3104: attribute, the attribute is translated into a decimal number in arabic
1.37 cvs 3105: numerals. If another form is desired, the <tt>VALUE</tt> function must be
1.30 cvs 3106: used.</p>
3107:
3108: <p>The last available function returns, as a character string, the value of a
1.1 cvs 3109: counter, an attribute or a page number. This value can be presented in
1.37 cvs 3110: different styles. The keyword <tt>VALUE</tt> is followed (between
1.1 cvs 3111: parentheses) by the name of the counter, the name of the attribute, or the
1.18 cvs 3112: keyword <tt>PageNumber</tt> and the desired style, the two parameters being
1.37 cvs 3113: separated by a comma. The style is a keyword which indicates whether the
1.18 cvs 3114: value should be presented in arabic numerals (<tt>Arabic</tt>), lower-case
3115: roman numerals (<tt>LRoman</tt>), or upper-case roman numerals
3116: (<tt>URoman</tt>), or by an upper-case letter (<tt>Uppercase</tt>) or
3117: lower-case letter (<tt>Lowercase</tt>).</p>
1.30 cvs 3118:
3119: <p>For a page counter, the keyword <tt>PageNumber</tt> can be followed,
3120: between parentheses, by the name of the view from which to obtain the page
1.37 cvs 3121: number. By default, the first view declared in the <tt>VIEWS</tt> section is
3122: used. The value obtained is the number of the page on which is found the
1.30 cvs 3123: element that is using the variable in a <tt>Content</tt> rule.</p>
3124:
3125: <p>For an ordinary counter, the name of the counter can be preceded by the
1.37 cvs 3126: keyword <tt>MaxRangeVal</tt> or <tt>MinRangeVal</tt>. These keywords mean
1.1 cvs 3127: that the value returned by the function is the maximum (minimum resp.) value
3128: taken by the counter in the whole document, not the value for the element
1.18 cvs 3129: concerned by the function.</p>
3130: <pre> Function = 'DATE' / 'FDATE' /
1.1 cvs 3131: 'DocName' / 'DirName' /
1.38 cvs 3132: 'ElemName' / 'AttributeName' / 'AttributeValue' /
1.1 cvs 3133: ConstID / ConstType ConstValue /
3134: AttrID /
3135: 'VALUE' '(' PageAttrCtr ','
3136: CounterStyle ')' .
1.6 cvs 3137: PageAttrCtr = 'PageNumber' [ '(' ViewID ')' ] /
1.1 cvs 3138: [ MinMax ] CounterID / AttrID .
3139: CounterStyle = 'Arabic' / 'LRoman' / 'URoman' /
3140: 'Uppercase' / 'Lowercase' .
1.18 cvs 3141: MinMax = 'MaxRangeVal' / 'MinRangeVal' .</pre>
1.30 cvs 3142:
1.18 cvs 3143: <blockquote class="example">
1.30 cvs 3144: <p><strong>Example:</strong></p>
3145:
3146: <p>To make today's date appear at the top of the first page of a report, a
3147: <a href="#sectc4232"><tt>CREATE</tt> rule</a> associated with the
3148: Report_Title element type generates a presentation box whose content
3149: (specified by the <tt>Content</tt> rule of that presentation box) is the
3150: variable:</p>
3151: <pre>VAR
1.18 cvs 3152: Todays_date : TEXT 'Version of ' DATE;</pre>
1.30 cvs 3153:
3154: <p>To produce, before each section title, the chapter number (in upper-case
3155: roman numerals) followed by the section number (in arabic numerals), two
3156: counters must be defined:</p>
3157: <pre>COUNTERS
1.1 cvs 3158: ChapterCtr : RANK OF Chapter;
1.18 cvs 3159: SectionCtr : RANK OF Section;</pre>
1.30 cvs 3160:
3161: <p>and the Section_Title element must create a presentation box whose
3162: content is the variable</p>
3163: <pre>VAR
1.1 cvs 3164: SectionNum : VALUE (ChapterCtr, URoman) TEXT '-'
1.18 cvs 3165: VALUE (SectionCtr, Arabic);</pre>
1.30 cvs 3166:
3167: <p>In order to make the page number on which each section begins appear in
3168: the table of contents view next to the section title, each Section_Title
3169: element must create a presentation box, visible only in the table of
3170: contents view, whose content is the variable:</p>
3171: <pre>VAR
1.1 cvs 3172: TitlePageNume :
1.18 cvs 3173: VALUE (PageNumber(Full_text), Arabic);</pre>
3174: </blockquote>
3175: </div>
1.1 cvs 3176:
1.18 cvs 3177: <div class="subsection">
1.37 cvs 3178: <h3><a name="sectc427" id="sectc427">Default presentation rules</a></h3>
1.1 cvs 3179:
1.30 cvs 3180: <p>In order to avoid having to specify, for each element type defined in the
1.1 cvs 3181: structure schema, values for every one of the numerous presentation
1.34 cvs 3182: properties, the presentation schema allows the definition of a set of default
1.37 cvs 3183: presentation rules. These rules apply to all the boxes of the elements
1.1 cvs 3184: defined in the structure schema and to the presentation boxes and page layout
1.37 cvs 3185: boxes defined in the presentation schema. Only rules which differ from these
1.18 cvs 3186: default need to be specified in other sections of the presentation schema.</p>
1.30 cvs 3187:
3188: <p>For the primary view, the default rules can define every presentation
1.34 cvs 3189: property, but not the <a href="#presfunct">presentation functions</a> or the
1.18 cvs 3190: <a href="#sectc4223">linebreaking conditions</a> (the <tt>NoBreak1</tt>,
3191: <tt>NoBreak2</tt>, and <tt>Gather</tt> rules).</p>
1.30 cvs 3192:
3193: <p>In a presentation schema, the default presentation rules section is
3194: optional; in this case, the <tt>DEFAULT</tt> keyword is also absent and the
3195: following rules are considered to be the default rules:</p>
1.26 cvs 3196: <pre> Visibility: Enclosing =;
3197: VertRef: * . Left;
3198: HorizRef: Enclosed . HRef;
3199: Height: Enclosed . Height;
3200: Width: Enclosed . Width;
3201: VertPos: Top = Previous . Bottom;
3202: HorizPos: Left = Enclosing . Left;
1.49 ! quint 3203: Float: None;
! 3204: Clear: None;
1.26 cvs 3205: MarginTop: 0;
3206: MarginRight: 0;
3207: MarginBottom: 0;
3208: MarginLeft: 0;
3209: PaddingTop: 0;
3210: PaddingRight: 0;
3211: PaddingBottom: 0;
3212: PaddingLeft: 0;
3213: BorderTopWidth: 0;
3214: BorderRightWidth: 0;
3215: BorderBottomWidth: 0;
3216: BorderLeftWidth: 0;
3217: BorderTopColor: Foreground;
3218: BorderRightColor: Foreground;
3219: BorderBottomColor: Foreground;
3220: BorderLeftColor: Foreground;
3221: BorderTopStyle: None;
3222: BorderRightStyle: None;
3223: BorderBottomStyle: None;
3224: BorderLeftStyle: None;
3225: VertOverflow: No;
3226: HorizOverflow: No;
3227: Size: Enclosing =;
3228: Style: Enclosing =;
3229: Weight: Enclosing =;
3230: Font: Enclosing =;
3231: Underline: Enclosing =;
3232: Thickness: Enclosing =;
3233: Indent: Enclosing =;
3234: LineSpacing: Enclosing =;
3235: Adjust: Enclosing =;
3236: Hyphenate: Enclosing =;
1.40 quint 3237: Direction: Enclosing =;
1.43 quint 3238: UnicodeBidi: Enclosing =;
1.26 cvs 3239: PageBreak: Yes;
3240: LineBreak: Yes;
3241: InLine: Yes;
3242: Depth: 0;
3243: LineStyle: Enclosing =;
3244: LineWeight: Enclosing =;
3245: FillPattern: Enclosing =;
3246: Background: Enclosing =;
1.48 quint 3247: Foreground: Enclosing =;
3248: Opacity: Enclosing =;
3249: FillOpacity: Enclosing =;
3250: StrokeOpacity: Enclosing =;</pre>
1.30 cvs 3251:
3252: <p>If other values are desired for the default rules, they must be defined
1.37 cvs 3253: explicitly in the default rules section. In fact, it is only necessary to
1.1 cvs 3254: define those default rules which differ from the ones above, since the rules
1.18 cvs 3255: above will be used whenever a rule is not explicitly named.</p>
1.30 cvs 3256:
1.37 cvs 3257: <p>Default rules for views other than the primary view can also be specified.
1.1 cvs 3258: Otherwise, the default rules for the primary views are applied to the other
1.18 cvs 3259: views.</p>
1.30 cvs 3260:
3261: <p>Default rules are expressed in the same way as <a
3262: href="#sectc4215">explicit rules for document elements</a>.</p>
1.18 cvs 3263: </div>
1.1 cvs 3264:
1.18 cvs 3265: <div class="subsection">
1.37 cvs 3266: <h3><a name="sectc428" id="sectc428">Presentation and page layout
3267: boxes</a></h3>
1.1 cvs 3268:
1.30 cvs 3269: <p>The presentation process uses elements which are not part of the logical
1.1 cvs 3270: structure of the document, such as pages (which are the page layout boxes) or
3271: alternatively, rules, numbers, or words introducing certain parts of the
3272: document, such as ``Summary'', ``Appendices'', ``Bibliography'', etc. (which
1.18 cvs 3273: are presentation boxes).</p>
1.30 cvs 3274:
3275: <p>After the word <tt>BOXES</tt>, each presentation or page layout box is
3276: defined by its name and a sequence of presentation rules which indicate how
1.37 cvs 3277: they must be displayed. These rules are the same as those which define the
3278: boxes associated with element of the logical structure of the document, with
3279: a single exception, the <a href="#sectc4231"><tt>Content</tt> rule</a> which
3280: is used only to specify the content of presentation boxes. The content of
3281: boxes associated with elements of the document structure is defined in each
3282: document or object and thus is not specified in the presentation schema,
3283: which applies to all documents or objects of a class.</p>
1.30 cvs 3284:
3285: <p>Among the rules which define a presentation box, certain ones can refer to
1.37 cvs 3286: another presentation box (for example, in their positional rules). If the
1.1 cvs 3287: designated box is defined after the box which designates it, a
1.18 cvs 3288: <tt>FORWARD</tt> instruction followed by the name of the designated box must
3289: appear before the designation.</p>
3290: <pre> 'BOXES' BoxSeq
1.30 cvs 3291: BoxSeq = Box < Box > .
1.1 cvs 3292: Box ='FORWARD' BoxID ';' /
3293: BoxID ':' ViewRuleSeq .
1.18 cvs 3294: BoxID = NAME .</pre>
3295: </div>
1.1 cvs 3296:
1.18 cvs 3297: <div class="subsection">
1.37 cvs 3298: <h3><a name="sectc429" id="sectc429">Presentation of structured
3299: elements</a></h3>
1.1 cvs 3300:
1.30 cvs 3301: <p>After the words <tt>RULES</tt>, the presentation schema gives the
3302: presentation rules that apply to the elements whose types are defined in the
1.37 cvs 3303: structure schema. Only those rules which differ from the <a
1.18 cvs 3304: href="#sectc427">default</a> must be specified in the <tt>RULES</tt>
3305: section.</p>
1.30 cvs 3306:
3307: <p>The rule definitions for each element type are composed of the name of the
1.1 cvs 3308: element type (as specified in the structure schema) followed by a colon and
1.18 cvs 3309: the set of rules specific to that type.</p>
1.30 cvs 3310:
3311: <p>The type name can be preceded by a star in the special case where the
1.18 cvs 3312: structure schema defines an <a href="#sectd3284">inclusion</a> without
1.1 cvs 3313: expansion (or with partial expansion) of a type with the same name as an
1.18 cvs 3314: element of defined in the structure schema.</p>
1.30 cvs 3315:
3316: <p>In the case where the element is a <a href="#sectd3285">mark pair</a>, but
1.18 cvs 3317: only in this case, the type name can be preceded by the keywords
1.37 cvs 3318: <tt>First</tt> or <tt>Second</tt>. These keywords indicate whether the rules
1.18 cvs 3319: that follow apply to the first or second mark of the pair.</p>
3320: <pre> 'RULES' PresentSeq
1.30 cvs 3321: PresentSeq = Present < Present > .
1.6 cvs 3322: Present = [ '*' ] [ FirstSec ] ElemID ':'
3323: ViewRuleSeq .
1.18 cvs 3324: FirstSec = 'First' / 'Second' .</pre>
1.30 cvs 3325:
3326: <p>A presentation schema can define presentation rules for base elements,
1.37 cvs 3327: which are defined implicitly in the structure schemas. In the English version
1.30 cvs 3328: of the presentation schema compiler, the base type names are the same as in
3329: the S language, but they are terminated by the <tt>_UNIT</tt> suffix:
1.18 cvs 3330: <tt>TEXT_UNIT</tt>, <tt>PICTURE_UNIT</tt>, <tt>SYMBOL_UNIT</tt>,
1.37 cvs 3331: <tt>GRAPHICS_UNIT</tt>. The base type names are written in upper-case
1.18 cvs 3332: letters.</p>
3333: </div>
3334:
3335: <div class="subsection">
1.37 cvs 3336: <h3><a name="sectc4210" id="sectc4210">Logical attribute presentation</a></h3>
1.18 cvs 3337:
1.30 cvs 3338: <p>After the keyword <tt>ATTRIBUTES</tt>, all attributes which are to have
1.37 cvs 3339: some effect on the presentation of the element to which they are attached
3340: must be mentioned, along with the corresponding presentation rules. This is
3341: true for both global attributes (which can be attached to all element types)
3342: and local attributes (which can only be attached to certain element
3343: types).</p>
1.30 cvs 3344:
3345: <p>Also mentioned in this section are attributes which imply an effect on
1.1 cvs 3346: elements in the subtree of the element to which they are attached. The
1.37 cvs 3347: presentation of these descendants can be modified as a function of the value
1.1 cvs 3348: of the attribute which they inherit, just as if it was attached to them
1.18 cvs 3349: directly.</p>
1.30 cvs 3350:
3351: <p>The specification for each attribute includes the attribute's name,
3352: followed by an optional value specification and, after a colon, a set of
1.37 cvs 3353: rules. The set of rules must contain at least one rule.</p>
1.30 cvs 3354:
1.37 cvs 3355: <p>When there is no value specification, the rules are applied to all
3356: elements which carry the attribute, no matter what their value. When the
3357: rules must only apply when the attribute has certain values, these values
3358: must be specified. Thus, the same attribute can appear in the
3359: <tt>ATTRIBUTES</tt> section several times, with each appearance having a
3360: different value specification. However, reference attributes never have a
3361: value specification and, as a result, can only appear once in the
3362: <tt>ATTRIBUTES</tt> section.</p>
1.30 cvs 3363:
3364: <p>To specify that the presentation rules apply to some of the descendants of
3365: the element having the attribute, the name of the affected element type is
1.37 cvs 3366: given, between parentheses, after the attribute name. This way, the
3367: presentation rules for the attribute will be applied to the element having
3368: the attribute, if it is of the given type, and to all of its descendants of
3369: the given type. In the case where this type is a <a href="#sectd3285">mark
3370: pair</a>, but only in this case, the type name can be preceded by the
3371: keywords <tt>First</tt> or <tt>Second</tt>. These keywords indicate whether
3372: the rules that follow apply to the first or second mark of the pair. If the
3373: rule must apply to several different element types, the specification must be
3374: repeated for each element type.</p>
1.30 cvs 3375:
3376: <p>The specification of values for which the presentation rules will be
3377: applied varies according to the type of the attribute:</p>
1.18 cvs 3378: <dl>
1.30 cvs 3379: <dt>numeric attribute</dt>
3380: <dd>If the rules are to apply for one value of the attribute, then the
1.37 cvs 3381: attribute name is followed by an equals sign and this value. If the
1.30 cvs 3382: rules are to apply for all values less than (or greater than) a
3383: threshold value, non-inclusive, the attribute name followed by a '<'
1.37 cvs 3384: sign (or a '>' sign, respectively) and the threshold value. If the
3385: rules must apply to a range of values, the attribute name is followed
3386: by the word '<tt>IN</tt>' and the two bounds of the range, enclosed in
3387: brackets and separated by two periods ('<tt>..</tt>'). In the case of
3388: ranges, the values of the bounds are included in the range.
1.30 cvs 3389: <p>The threshold value in the comparisons can be the value of an
1.37 cvs 3390: attribute attached to an ancestor element. In this case, the attribute
1.30 cvs 3391: name is given instead of a constant value.</p>
1.37 cvs 3392: <p>It is also possible to write rules which apply only when a
3393: comparison between two different attributes of the element's ancestors
3394: is true. In this case, the first attribute name is followed by a
3395: comparison keyword and the name of the second attribute. The comparison
3396: keywords are <tt>EQUAL</tt> (simple equality), <tt>LESS</tt>
3397: (non-inclusive less than), and <tt>GREATER</tt> (non-inclusive greater
3398: than).</p>
1.30 cvs 3399: </dd>
3400: <dt>text attribute</dt>
3401: <dd>If the rules are to apply for one value of the attribute, then the
3402: attribute name is followed by an equals sign and this value.</dd>
3403: <dt>reference attribute</dt>
3404: <dd>There is never a value specification; the rules apply no matter what
3405: element is designated by the attribute.</dd>
3406: <dt>enumerated attribute</dt>
3407: <dd>If the rules are to apply for one value of the attribute, then the
3408: attribute name is followed by an equals sign and this value.</dd>
1.18 cvs 3409: </dl>
1.30 cvs 3410:
3411: <p>The order in which the rules associated with a numeric attribute are
1.37 cvs 3412: defined is important. When multiple sets of rules can be applied, the first
1.30 cvs 3413: set declared is the one used.</p>
3414:
3415: <p>Rules for attributes have priority over both default rules and rules
1.37 cvs 3416: associated with element types. The attribute rules apply to the element to
3417: which the attribute is attached. It is the rules which apply to the
1.1 cvs 3418: surrounding elements (and especially to the descendants) which determine the
3419: effect of the attribute rules on the environment ( and especially on the
1.18 cvs 3420: terminal elements of the structure).</p>
3421: <pre> 'ATTRIBUTES' PresAttrSeq
1.30 cvs 3422: PresAttrSeq = PresAttr < PresAttr > .
1.1 cvs 3423: PresAttr = AttrID [ '(' [ FirstSec ] ElemID ')' ]
3424: [ AttrRelation ] ':' ViewRuleSeq .
3425: AttrID = NAME .
3426: AttrRelation ='=' AttrVal /
1.30 cvs 3427: '>' [ '-' ] MinValue /
1.1 cvs 3428: '<' [ '-' ] MaxValue /
3429: 'IN' '[' [ '-' ] LowerBound '..'
3430: [ '-' ] UpperBound ']' /
3431: 'GREATER' AttrID /
3432: 'EQUAL' AttrID /
3433: 'LESS' AttrID .
3434: AttrVal = [ '-' ] EqualNum / EqualText /
3435: AttrValue .
3436: MinValue = NUMBER .
3437: MaxValue = NUMBER .
3438: LowerBound = NUMBER .
3439: UpperBound = NUMBER.
3440: EqualNum = NUMBER .
3441: EqualText = STRING .
1.18 cvs 3442: AttrValue = NAME .</pre>
1.30 cvs 3443:
1.37 cvs 3444: <p>In presentation rules associated with a numeric attribute (and only in
3445: such rules), the attribute name can be used in place of a numeric value. In
3446: this case, the value of the attribute is used in the application of the rule.
3447: Thus, the attribute can represent a relation between the size of two boxes,
3448: the height and width of a box, the height of an area where page breaks are
3449: prohibited, the distance between two boxes, the position of the reference
3450: axis of a box, the interline spacing, the indentation of the first line, the
1.18 cvs 3451: visibility, the depth (z-order), or the character set.</p>
1.30 cvs 3452:
1.37 cvs 3453: <p>The presentation rules associated with reference attributes, it is
3454: possible to use the element designated by the attribute as a reference box in
3455: a positional or extent rule. This element is represented in the <a
1.18 cvs 3456: href="#sectc4218">position</a> or <a href="#sectc4219">extent</a> rule by the
3457: keyword <tt>Referred</tt>.</p>
1.30 cvs 3458:
1.18 cvs 3459: <blockquote class="example">
1.30 cvs 3460: <p><strong>Example:</strong></p>
3461:
1.37 cvs 3462: <p>In all structure schemas, there is a global Language attribute defined
3463: as follows:</p>
1.30 cvs 3464: <pre>ATTR
1.18 cvs 3465: Language = TEXT;</pre>
1.30 cvs 3466:
3467: <p>The following rules would make French text be displayed in roman
3468: characters and English text be displayed in italics:</p>
3469: <pre>ATTRIBUTES
1.1 cvs 3470: Language = 'French' :
1.6 cvs 3471: Style : Roman;
1.1 cvs 3472: Language = 'English' :
1.18 cvs 3473: Style : Italics;</pre>
1.30 cvs 3474:
3475: <p>Using these rules, when the user puts the Language attribute with the
3476: value 'English' on the summary of a document, every character string
1.37 cvs 3477: (terminal elements) contained in the summary are displayed in italics. See
1.30 cvs 3478: the <a href="#sectd42252"><tt>Style</tt> rule</a>.</p>
1.18 cvs 3479: </blockquote>
1.30 cvs 3480:
1.18 cvs 3481: <blockquote class="example">
1.30 cvs 3482: <p><strong>Example:</strong></p>
3483:
3484: <p>A numeric attribute representing the importance of the part of the
3485: document to which it is attached can be defined:</p>
3486: <pre>ATTR
1.18 cvs 3487: Importance = INTEGER;</pre>
1.30 cvs 3488:
3489: <p>In the presentation schema, the importance of an element is reflected in
3490: the choice of character size, using the following rules.</p>
3491: <pre>ATTRIBUTES
1.1 cvs 3492: Importance < 2 :
3493: Size : 1;
3494: Importance IN [2..4] :
3495: Size : Importance;
3496: Importance = 10 :
3497: Size : 5;
1.30 cvs 3498: Importance > 4 :
1.18 cvs 3499: Size : 4;</pre>
1.30 cvs 3500:
3501: <p>Thus, the character size corresponds to the value of the Importance
3502: attribute; its value is</p>
3503: <ul>
3504: <li>the value of the Importance attribute when the value is between 2 and
3505: 4 (inclusive),</li>
3506: <li>1, when the value of the Importance attribute is less than 2,</li>
3507: <li>4, when the value of the Importance attribute is greater than 4,</li>
3508: <li>5, when the value of the Importance attribute is 10.</li>
3509: </ul>
3510:
1.37 cvs 3511: <p>The last case (value 5) must be defined before the case which handles
3512: all Importance values greater than 4, because the two rules are not
3513: disjoint and the first one defined will have priority. Otherwise, when the
3514: Importance attribute has value 10, the font size will be 4.</p>
1.18 cvs 3515: </blockquote>
1.30 cvs 3516:
1.18 cvs 3517: <blockquote class="example">
1.30 cvs 3518: <p><strong>Example:</strong></p>
3519:
3520: <p>Suppose the structure defines a list element which can have an attribute
3521: defining the type of list (numbered or not):</p>
3522: <pre>STRUCT
1.1 cvs 3523: list (ATTR list_type = enumeration, dash)
1.18 cvs 3524: = LIST OF (list_item = TEXT);</pre>
1.30 cvs 3525:
3526: <p>Then, the presentation schema could use the attribute placed on the list
3527: element to put either a dash or a number before the each element of the
3528: list:</p>
3529: <pre>ATTRIBUTES
1.1 cvs 3530: list_type (list_item) = enumeration :
3531: CreateBefore (NumberBox);
3532: list_type (list_item) = dash :
1.18 cvs 3533: CreateBefore (DashBox);</pre>
3534: </blockquote>
1.30 cvs 3535:
1.18 cvs 3536: <blockquote class="example">
1.30 cvs 3537: <p><strong>Example:</strong></p>
3538:
1.37 cvs 3539: <p>Suppose that two attributes are defined in the structure schema. The
3540: first is a numeric global attribute called ``version''. The other is a
1.30 cvs 3541: local attribute defined on the root of the document called
3542: ``Document_version'':</p>
3543: <pre>STRUCTURE Document
1.1 cvs 3544: ATTR
3545: version = INTEGER;
3546: STRUCT
3547: Document (ATTR Document_version = INTEGER) =
3548: BEGIN
3549: SomeElement ;
3550: ...
3551: SomeOtherElement ;
3552: END ;
1.18 cvs 3553: ...</pre>
1.30 cvs 3554:
3555: <p>These attributes can be used in the presentation schema to place change
3556: bars in the margin next to elements whose version attribute has a value
3557: equal to the Document_version attribute of the root and to place a star in
3558: margin of elements whose version attribute is less than the value of the
3559: root's Document_version attribute:</p>
3560: <pre>ATTRIBUTES
1.1 cvs 3561: version EQUAL Document_version :
3562: CreateBefore (ChangeBarBox) ;
3563: version LESS Document_version :
1.18 cvs 3564: CreateBefore (StarBox) ;</pre>
3565: </blockquote>
3566: </div>
1.1 cvs 3567:
1.18 cvs 3568: <div class="subsection">
1.37 cvs 3569: <h3><a name="sectc4212" id="sectc4212">Value transmission rules</a></h3>
1.1 cvs 3570:
1.30 cvs 3571: <p>The last section of a presentation schema, which is optional, serves to
1.1 cvs 3572: defines the way in which a document transmits certain values to its
1.37 cvs 3573: sub-documents. A sub-document is an document <a
1.18 cvs 3574: href="#inclusion">included</a> without expansion or with partial expansion.
1.1 cvs 3575: The primary document can transmit to its sub-documents the values of certain
3576: counters or the textual content of certain of its elements, as a function of
1.18 cvs 3577: their type.</p>
1.30 cvs 3578:
3579: <p>The sub-documents receive these values in attributes which must be defined
1.37 cvs 3580: in their structure schema as local attributes of the root element. The types
1.30 cvs 3581: of these attributes must correspond to the type of the value which they
3582: receive: numeric attributes for receiving the value of a counter, textual
3583: attributes for receiving the content of an element.</p>
3584:
3585: <p>In the structure schema of the primary document, there appears at the end,
1.37 cvs 3586: after the <tt>TRANSMIT</tt> keyword, a sequence of transmission rules. Each
1.1 cvs 3587: rule begins with the name of the counter to transmit or of the element type
1.37 cvs 3588: whose textual content will be transmitted. This name is followed by the
3589: keyword <tt>To</tt> and the name of the attribute of the sub-document to
3590: which the value is transmitted. The sub-document class is indicated between
3591: parentheses after the name of the attribute. The transmission rule ends with
1.18 cvs 3592: a semicolon.</p>
1.30 cvs 3593: <pre> TransmitSeq = Transmit < Transmit > .
1.1 cvs 3594: Transmit = TypeOrCounter 'To' ExternAttr
3595: '(' ElemID ')' ';' .
3596: TypeOrCounter = CounterID / ElemID .
1.18 cvs 3597: ExternAttr = NAME .</pre>
1.30 cvs 3598:
1.18 cvs 3599: <blockquote class="example">
1.30 cvs 3600: <p><strong>Example:</strong></p>
3601:
3602: <p>Consider a Book document class which includes instances of the Chapter
1.37 cvs 3603: document class. These classes might have the following schemas:</p>
1.30 cvs 3604: <pre>STRUCTURE Book
1.1 cvs 3605: STRUCT
3606: Book = BEGIN
3607: Title = Text;
3608: Body = LIST OF (Chapter INCLUDED);
3609: END;
3610: ...
3611:
3612: STRUCTURE Chapter
3613: STRUCT
3614: Chapter (ATTR FirstPageNum = Integer;
3615: ChapterNum = Integer;
3616: CurrentTitle = Text) =
1.6 cvs 3617: BEGIN
3618: ChapterTitle = Text;
3619: ...
3620: END;
1.18 cvs 3621: ...</pre>
1.30 cvs 3622:
3623: <p>Then the presentation schema for books could define chapter and page
3624: counters. The following transmission rules in the book presentation schema
3625: would transmit values for the three attributes defined at the root of each
3626: chapter sub-document.</p>
3627: <pre>PRESENTATION Book;
1.1 cvs 3628: VIEWS
3629: Full_text;
3630: COUNTERS
3631: ChapterCtr: Rank of Chapter;
3632: PageCtr: Rank of Page(Full_text);
3633: ...
3634: TRANSMIT
3635: PageCtr TO FirstPageNum(Chapter);
3636: ChapterCtr TO ChapterNum(Chapter);
3637: Title TO CurrentTitle(Chapter);
1.18 cvs 3638: END</pre>
1.30 cvs 3639:
3640: <p>Thus, each chapter included in a book can number its pages as a function
3641: of the number of pages preceding it in the book, can make the chapter's
3642: number appear before the number of each of its sections, or can place the
3643: title of the book at the top of each page.</p>
1.18 cvs 3644: </blockquote>
3645: </div>
1.1 cvs 3646:
1.18 cvs 3647: <div class="subsection">
1.37 cvs 3648: <h3><a name="sectc4213" id="sectc4213">Presentation rules</a></h3>
1.1 cvs 3649:
1.30 cvs 3650: <p>Whether defining the appearance of a presentation or page layout box, an
1.1 cvs 3651: element type, or an attribute value, the set of presentation rules that apply
1.18 cvs 3652: is always defined in the same way.</p>
1.30 cvs 3653:
3654: <p>Normally, a set of presentation rules is placed between the keywords
1.18 cvs 3655: <tt>BEGIN</tt> and <tt>END</tt>, the keyword <tt>END</tt> being followed by a
1.37 cvs 3656: semicolon. The first section of this block defines the rules that apply to
1.18 cvs 3657: the primary view, if the <a href="#sectc427">default rules</a> are not
1.37 cvs 3658: completely suitable. Next comes the rules which apply to specific other
1.1 cvs 3659: views, with a rule sequence for each view for which the default rules are not
1.37 cvs 3660: satisfactory. If the default rules are suitable for the non-primary views,
3661: there will not be any specific rules for these views. If there is only one
1.18 cvs 3662: rule which applies to all views then the keywords <tt>BEGIN</tt> and
3663: <tt>END</tt> need not appear.</p>
1.30 cvs 3664:
3665: <p>For each view, it is only necessary to specify those rules which differ
3666: from the default rules for the view, so that for certain views (or even all
3667: views), there may be no specific rules.</p>
3668:
3669: <p>The specific rules for a non-primary view are introduced by the <a
1.37 cvs 3670: name="inkeyword" id="inkeyword"><tt>IN</tt> keyword</a>, followed by the view
3671: name. The rules for that view follow, delimited by the keywords
3672: <tt>BEGIN</tt> and <tt>END</tt>, or without these two keywords when there is
3673: only one rule.</p>
1.30 cvs 3674:
3675: <p><strong>Note:</strong> the view name which follows the <tt>IN</tt> keyword
1.1 cvs 3676: must not be the name of the primary view, since the rules for that view are
1.18 cvs 3677: found before the rules for the other views.</p>
1.30 cvs 3678:
3679: <p>Within each block concerning a view, other blocks can appear, delimited by
1.37 cvs 3680: the same keywords <tt>BEGIN</tt> and <tt>END</tt>. Each of these blocks
3681: gathers the presentation rules that apply, for a given view, only when a
3682: given condition is satisfied. Each block is preceded by a condition
3683: introduced by the <tt>IF</tt> keyword. If such a conditional block contains
3684: only one rule, the keywords <tt>BEGIN</tt> and <tt>END</tt> can be
3685: omitted.</p>
3686:
3687: <p>Although the syntax allows any presentation rule to appear in a
3688: conditional block, only <a href="#sectc4232">creation rules</a> are allowed
3689: after any condition; other rules are allowed only after conditions
3690: <tt>Within</tt> and ElemID. In addition, the following rules cannot be
3691: conditional: <tt>PageBreak, LineBreak, Inline, Gather</tt>.</p>
1.30 cvs 3692:
3693: <p>For a given view, the rules that apply without any condition must appear
1.37 cvs 3694: before the first conditional block. If some rules apply only when none of the
3695: specified condition holds, they are grouped in a block preceded by the
3696: keyword <tt>Otherwise</tt>, and that block must appear after the last
3697: conditionnal block concerning the same view.</p>
1.30 cvs 3698: <pre> ViewRuleSeq = 'BEGIN' < RulesAndCond > < ViewRules >
1.1 cvs 3699: 'END' ';' /
3700: ViewRules / CondRules / Rule .
3701: RulesAndCond = CondRules / Rule .
3702: ViewRules = 'IN' ViewID CondRuleSeq .
1.30 cvs 3703: CondRuleSeq = 'BEGIN' < RulesAndCond > 'END' ';' /
1.1 cvs 3704: CondRules / Rule .
1.30 cvs 3705: CondRules = CondRule < CondRule >
1.1 cvs 3706: [ 'Otherwise' RuleSeq ] .
3707: CondRule = 'IF' ConditionSeq RuleSeq .
1.30 cvs 3708: RulesSeq = 'BEGIN' Rule < Rule > 'END' ';' /
1.18 cvs 3709: Rule .</pre>
1.30 cvs 3710:
1.18 cvs 3711: <blockquote class="example">
1.30 cvs 3712: <p><strong>Example:</strong></p>
3713:
3714: <p>The following rules for a report's title make the title visible in the
1.37 cvs 3715: primary view and invisible in the table of contents and in the formula
3716: views (see the <a href="#sectc4224"><tt>Visibility</tt> rule</a>).</p>
1.30 cvs 3717: <pre>Title : BEGIN
1.1 cvs 3718: Visibility : 1;
3719: ... {Other rules for the primary view}
3720: IN Table_of_contents
3721: Visibility : 0;
3722: IN Formulas
3723: Visibility : 0;
1.18 cvs 3724: END;</pre>
3725: </blockquote>
3726: </div>
1.1 cvs 3727:
1.18 cvs 3728: <div class="subsection">
1.37 cvs 3729: <h3><a name="sectc4214" id="sectc4214">Conditions applying to presentation
3730: rules</a></h3>
1.1 cvs 3731:
1.37 cvs 3732: <p>Many conditions can be applied to presentation rules. Conditions allow
3733: certain presentation rules to apply only in certain cases. These conditions
3734: can be based on the structural position of the element. They can be based on
1.1 cvs 3735: whether the element has references, and what type of references, whether the
1.42 quint 3736: element has attributes, possibly with certains values, whether the element is
3737: empty or not, whether the element is the root of its document or not. They
3738: can also be based on the value of a counter.</p>
1.30 cvs 3739:
1.37 cvs 3740: <p>It is possible to specify several conditions which must all be true for
3741: the rules to apply.</p>
1.30 cvs 3742:
1.37 cvs 3743: <p>A set of conditions is specified by the <tt>IF</tt> keyword. This keyword
1.30 cvs 3744: is followed by the sequence of conditions, separated by the <tt>AND</tt>
3745: keyword. Each condition is specified by a keyword which defines the condition
3746: type. In some cases, the keyword is followed by other data, which specify the
1.42 quint 3747: condition more precisely. The keyword is not present if the condition depends
3748: on the element type or an attribute associated with the element.</p>
1.30 cvs 3749:
3750: <p>An elementary condition can be negative; it is then preceded by the
1.18 cvs 3751: <tt>NOT</tt> keyword.</p>
1.30 cvs 3752:
3753: <p>When the presentation rule(s) controlled by the condition apply to a
3754: reference element or a reference attribute, an elementary condition can also
1.37 cvs 3755: apply to element referred by this reference. The <tt>Target</tt> keyword is
3756: used for that purpose. It must appear before the keyword defining the
1.30 cvs 3757: condition type.</p>
1.18 cvs 3758: <pre> CondRule ='IF' ConditionSeq RuleSeq .
1.30 cvs 3759: ConditionSeq = Condition < 'AND' Condition > .
1.1 cvs 3760: Condition = [ 'NOT' ] [ 'Target' ] ConditionElem .
3761: ConditionElem ='First' / 'Last' /
3762: [ 'Immediately' ] 'Within' [ NumParent ]
3763: ElemID [ ExtStruct ] /
3764: ElemID /
3765: 'Referred' / 'FirstRef' / 'LastRef' /
3766: 'ExternalRef' / 'InternalRef' / 'CopyRef' /
1.44 quint 3767: [ 'Inherited' ] AttrID [ '=' Value ] /
1.1 cvs 3768: 'AnyAttributes' / 'FirstAttr' / 'LastAttr' /
3769: 'UserPage' / 'StartPage' / 'ComputedPage' /
1.33 cvs 3770: 'Empty' / 'Root' /
1.1 cvs 3771: '(' [ MinMax ] CounterName CounterCond ')' /
3772: CondPage '(' CounterID ')' .
3773: NumParent = [ GreaterLess ] NParent .
1.30 cvs 3774: GreaterLess ='>' / '<' .
1.1 cvs 3775: NParent = NUMBER.
1.6 cvs 3776: ExtStruct ='(' ElemID ')' .
1.42 quint 3777: Value = [ '-' ] IntegerVal / TextVal / AttrValue .
1.30 cvs 3778: CounterCond ='<' MaxCtrVal / '>' MinCtrVal /
1.1 cvs 3779: '=' EqCtrVal /
3780: 'IN' '[' ['-'] MinCtrBound '.' '.'
3781: ['-'] MaxCtrBound ']' .
3782: PageCond ='Even' / 'Odd' / 'One' .
3783: MaxCtrVal = NUMBER .
3784: MinCtrVal = NUMBER .
3785: EqCtrVal = NUMBER .
3786: MaxCtrBound = NUMBER .
1.18 cvs 3787: MinCtrBound = NUMBER .</pre>
1.1 cvs 3788:
1.18 cvs 3789: <div class="subsubsection">
1.37 cvs 3790: <h4><a name="sectd42141" id="sectd42141">Conditions based on the logical
3791: position of the element</a></h4>
1.30 cvs 3792:
3793: <p>The condition can be on the position of the element in the document's
1.37 cvs 3794: logical structure tree. It is possible to test whether the element is the
1.30 cvs 3795: first (<tt>First</tt>) or last (<tt>Last</tt>) among its siblings or if it is
3796: not the first (<tt>NOT First</tt>) or not the last (<tt>NOT Last</tt>). These
1.18 cvs 3797: conditions can be associated only with <a href="#sectc4232">creation
3798: rules</a>.</p>
1.30 cvs 3799:
1.33 cvs 3800: <p>It is possible to test if the element is the root of its document (keyword
3801: <code>Root</code>).</p>
3802:
1.30 cvs 3803: <p>It is also possible to test if the element is contained in an element of a
1.18 cvs 3804: given type (<tt>Within</tt>) or if it is not (<tt>NOT Within</tt>). The type
3805: is indicated after the keyword <tt>Within</tt>. If that element type is
1.1 cvs 3806: defined in a structure schema which is not the one which corresponds to the
3807: presentation schema, the type name of this element must be followed, between
1.18 cvs 3808: parentheses, by the name of the structure schema which defines it.</p>
1.30 cvs 3809:
3810: <p>If the keyword <tt>Within</tt> is preceded by <tt>Immediately</tt>, the
1.18 cvs 3811: condition is satisfied only if the <em>parent</em> element has the type
3812: indicated. If the word <tt>Immediately</tt> is missing, the condition is
3813: satisfied if any <em>ancestor</em> has the type indicated.</p>
1.30 cvs 3814:
3815: <p>An integer <i>n</i> can appear between the keyword <tt>Within</tt> and the
1.37 cvs 3816: type. It specifies the number of ancestors of the indicated type that must be
3817: present for the condition to be satisfied. If the keyword
1.18 cvs 3818: <tt>Immediately</tt> is also present, the <i>n</i> immediate ancestors of the
1.37 cvs 3819: element must have the indicated type. The integer <i>n</i> must be positive
3820: or zero. It can be preceded by <tt><</tt> or <tt>></tt> to indicate a
3821: maximum or minimum number of ancestors. If these symbols are missing, the
3822: condition is satisfied only if it exists exactly <i>n</i> ancestors. When
1.30 cvs 3823: this number is missing, it is equivalent to > 0.</p>
1.42 quint 3824: </div>
3825:
3826: <div class="subsubsection">
3827: <h4><a name="sectd421411" id="sectd421411">Conditions based on the element
3828: type</a></h4>
1.30 cvs 3829:
3830: <p>If the condition applies to presentation rules associated with an
3831: attribute, in the <tt>ATTRIBUTES</tt> section of the presentation schema, the
3832: condition can be simply an element name. Presentation rules are then executed
3833: only if the attribute is attached to an element of that type. The keyword
3834: <tt>NOT</tt> before the element name indicates that the presentation rules
3835: must be executed only if the element is not of the type indicated.</p>
1.18 cvs 3836: </div>
1.1 cvs 3837:
1.18 cvs 3838: <div class="subsubsection">
1.37 cvs 3839: <h4><a name="sectd42142" id="sectd42142">Conditions on references</a></h4>
1.30 cvs 3840:
3841: <p>References may be taken into account in conditions, which can be based on
3842: the fact that the element, or one of its ancestors, is designated by a at
3843: least one reference (<tt>Referred</tt>) or by none (<tt>NOT
3844: Referred</tt>).</p>
3845:
3846: <p>If the element or attribute to which the condition is attached is a
3847: reference, the condition can be based on the fact that it acts as the first
3848: reference to the designated element (<tt>FirstRef</tt>), or as the last
3849: (<tt>LastRef</tt>), or as a reference to an element located in another
3850: document (<tt>ExternalRef</tt>) or in the same document
3851: (<tt>InternalRef</tt>).</p>
1.1 cvs 3852:
1.30 cvs 3853: <p>The condition can also be based on the fact that the element is an <a
1.37 cvs 3854: href="#inclusion">inclusion</a>. This is noted (<tt>CopyRef</tt>).</p>
1.30 cvs 3855:
3856: <p>Like all conditions, conditions on references can be inverted by the
1.18 cvs 3857: <tt>NOT</tt> keyword. These conditions can be associated only with <a
3858: href="#sectc4232">creation rules</a>.</p>
3859: </div>
1.1 cvs 3860:
1.18 cvs 3861: <div class="subsubsection">
1.37 cvs 3862: <h4><a name="sectd42143" id="sectd42143">Conditions on logical
3863: attributes</a></h4>
1.30 cvs 3864:
3865: <p>The condition can be based on the presence or absence of attributes
3866: associated with the element, no matter what the attributes or their values.
3867: The <tt>AnyAttributes</tt> keyword expresses this condition.</p>
1.1 cvs 3868:
1.42 quint 3869: <p>A condition can also be based on the presence or absence of a given
3870: attribute associated with the element. This condition is simply expressed by
1.44 quint 3871: the name of the attribute. The condition may also be based on the presence of
3872: a given attribute associated with a parent of the element. This condition is
3873: expressed by the <code>Inherited</code> keyword, followed by the name of the
3874: attribute.</p>
1.42 quint 3875:
3876: <p>The condition can be based on the value of a given attribute. It is then
3877: expressed by the name of the attribute, followed by the '=' sign and the
3878: value to be tested. Depending on the type of attribute, the value is simply
3879: an integer (possibly negative), the name of one of the possible values of the
1.44 quint 3880: attribute or a quoted character string. If the attribute with the specified
3881: value has to be checked on the ancestors of the element, this condition
3882: starts with the keyword <code>Inherited.</code></p>
1.42 quint 3883:
1.30 cvs 3884: <p>If the condition appears in the presentation rules of an attribute, the
1.37 cvs 3885: <tt>FirstAttr</tt> and <tt>LastAttr</tt> keywords can be used to indicate
3886: that the rules must only be applied if this attribute is the first attribute
3887: for the element or if it is the last (respectively). These conditions can
3888: also be inverted by the <tt>NOT</tt> keyword. These conditions can be
3889: associated only with <a href="#sectc4232">creation rules</a>.</p>
1.30 cvs 3890:
3891: <p>It is also possible to apply certain presentation rules only when the
3892: element being processed or one of its ancestors has a certain attribute,
1.37 cvs 3893: perhaps with a certain value. This can be done in the <a
1.18 cvs 3894: href="#sectc4210"><tt>ATTRIBUTES</tt> section</a>.</p>
3895: </div>
1.1 cvs 3896:
1.18 cvs 3897: <div class="subsubsection">
1.37 cvs 3898: <h4><a name="sectd42144" id="sectd42144">Conditions on page breaks</a></h4>
1.1 cvs 3899:
1.30 cvs 3900: <p>The page break base type (and only this type) can use the following
1.18 cvs 3901: conditions: <tt>ComputedPage</tt>, <tt>StartPage</tt>, and <tt>UserPage</tt>.
3902: The <tt>ComputedPage</tt> condition indicates that the presentation rule(s)
1.37 cvs 3903: should apply if the page break was created automatically by Thot; the
3904: <tt>StartPage</tt> condition is true if the page break is generated before
3905: the element by the <tt>Page</tt> rule; and the <tt>UserPage</tt> condition
3906: applies if the page break was inserted by the user.</p>
1.30 cvs 3907:
3908: <p>These conditions can be associated only with <a href="#sectc4232">creation
1.18 cvs 3909: rules</a>.</p>
3910: </div>
1.1 cvs 3911:
1.18 cvs 3912: <div class="subsubsection">
1.37 cvs 3913: <h4><a name="sectd42145" id="sectd42145">Conditions on the element's
3914: content</a></h4>
1.1 cvs 3915:
1.37 cvs 3916: <p>The condition can be based on whether or not the element is empty. An
1.30 cvs 3917: element which has no children or whose leaves are all empty is considered to
1.37 cvs 3918: be empty itself. This condition is expressed by the <tt>Empty</tt> keyword,
1.30 cvs 3919: optionally preceded by the <tt>NOT</tt> keyword. This condition can be
3920: associated only with <a href="#sectc4232">creation rules</a>.</p>
1.18 cvs 3921: </div>
1.1 cvs 3922:
1.18 cvs 3923: <div class="subsubsection">
1.37 cvs 3924: <h4><a name="sectd42146" id="sectd42146">Conditions on counters</a></h4>
1.1 cvs 3925:
1.30 cvs 3926: <p>Presentation rules can apply when the counter's value is one, is even or
3927: odd, is equal, greater than or less than a given value or falls in a range of
1.37 cvs 3928: values. This is particularly useful for creating header and footer boxes.
1.18 cvs 3929: These conditions can be associated only with <a href="#sectc4232">creation
3930: rules</a>.</p>
1.30 cvs 3931:
3932: <p>To compare the value of a counter to a given value, a comparison is given
1.1 cvs 3933: between parentheses. The comparison is composed of the counter name followed
3934: by an equals, greater than, or less than sign and the value to which the
1.37 cvs 3935: counter will be compared. A test for whether or not a counter's value falls
3936: in a range also appears within parentheses. In this case, the counter name is
1.18 cvs 3937: followed by the <tt>IN</tt> keyword and the range definition within brackets.
3938: The <tt>Even</tt>, <tt>Odd</tt> and <tt>One</tt> are used to test a counter's
3939: value and are followed by the counter name between parentheses.</p>
1.30 cvs 3940:
3941: <p>The list of possible conditions on counters is:</p>
1.18 cvs 3942: <dl>
1.30 cvs 3943: <dt><tt>Even (Counter)</tt></dt>
3944: <dd>the box is created only if the counter has an even value.</dd>
3945: <dt><tt>Odd (Counter)</tt></dt>
3946: <dd>the box is created only if the counter has an odd value.</dd>
3947: <dt><tt>One (Counter)</tt></dt>
3948: <dd>the box is created only the counter's value is 1.</dd>
3949: <dt><tt>NOT One (Counter)</tt></dt>
3950: <dd>the box is created, unless the counter's value is 1.</dd>
3951: <dt><tt>(Counter < Value)</tt></dt>
3952: <dd>the box is created only if the counter's value is less than
3953: Value.</dd>
3954: <dt><tt>(Counter > Value)</tt></dt>
3955: <dd>the box is created only if the counter's value is greater than
3956: Value.</dd>
3957: <dt><tt>(Counter = Value)</tt></dt>
3958: <dd>the box is created only if the counter's value is equal to Value.</dd>
3959: <dt><tt>NOT (Counter = Value)</tt></dt>
3960: <dd>the is created only if the counter's value is different than
3961: Value.</dd>
3962: <dt><tt>(Counter IN [MinValue..MaxValue])</tt></dt>
3963: <dd>the box is created only if the counter's value falls in the range
3964: bounded by MinValue and MaxValue (inclusive).</dd>
3965: <dt><tt>NOT (Counter IN [MinValue..MaxValue])</tt></dt>
3966: <dd>the box is created only if the value of the counter does not fall in
3967: the range bounded by MinValue and MaxValue (inclusive).</dd>
1.18 cvs 3968: </dl>
1.30 cvs 3969:
3970: <p><strong>Note:</strong> the <tt>NOT Even</tt> and <tt>NOT Odd</tt>
3971: conditions are syntactically correct but can be expressed more simply by
3972: <tt>Odd</tt> and <tt>Even</tt>, respectively.</p>
1.18 cvs 3973: </div>
3974: </div>
1.1 cvs 3975:
1.18 cvs 3976: <div class="subsection">
1.37 cvs 3977: <h3><a name="sectc4215" id="sectc4215">A presentation rule</a></h3>
1.1 cvs 3978:
1.34 cvs 3979: <p>A presentation rule defines either a presentation property or presentation
1.37 cvs 3980: function. The properties are:</p>
1.18 cvs 3981: <ul>
1.30 cvs 3982: <li>the position of the vertical and horizontal reference axes of the
3983: box,</li>
3984: <li>the position of the box in relation to other boxes,</li>
3985: <li>the height or width of the box, with overflow exceptions,</li>
3986: <li>the margins, padding and borders of the box,</li>
3987: <li>the characteristics of the lines contained in the box: linespacing,
1.40 quint 3988: indentation of the first line, hyphenation, writing direction</li>
1.30 cvs 3989: <li>the conditions for breaking the box across pages,</li>
3990: <li>the characteristics of the characters contained in the box: size, font,
3991: style, underlining,</li>
3992: <li>the depth of the box among overlapping boxes (often called stacking
3993: order),</li>
3994: <li>the characteristics of graphic elements contained in the box: style and
3995: thickness of lines, fill pattern for closed objects,</li>
1.37 cvs 3996: <li>the colors in text, graphics, pictures, and symbols contained in the
3997: box are displayed or printed,</li>
1.48 quint 3998: <li>the opacity of the element,</li>
1.30 cvs 3999: <li>for presentation boxes only, the contents of the box.</li>
4000: </ul>
4001:
1.37 cvs 4002: <p>The <a name="presfunct" id="presfunct">presentation functions</a> are:</p>
1.30 cvs 4003: <ul>
4004: <li>the creation of a presentation box</li>
4005: <li>the line-breaking or page-breaking style,</li>
4006: <li>the copying of another box,</li>
4007: <li>the display of the box background and border,</li>
4008: <li>the display of a background picture and its aspect.</li>
4009: </ul>
4010:
1.37 cvs 4011: <p>For each box and each view, every presentation property is defined once
4012: and only once, either explicitly or by the <a href="#sectc427">default
4013: rules</a>. In contrast, presentation functions are not obligatory and can
4014: appear many times for the same element. for example an element can create
4015: many presentation boxes. Another element may not use any presentation
1.18 cvs 4016: functions.</p>
1.30 cvs 4017:
1.34 cvs 4018: <p>Each rule defining a presentation property begins with a keyword followed
1.37 cvs 4019: by a colon. The keyword indicates the property which is the subject of the
4020: rule. After the keyword and the colon, the remainder of the rule varies. All
1.18 cvs 4021: rules are terminated by a semicolon.</p>
1.34 cvs 4022: <pre> Rule = Property ';' / PresFunc ';' .
1.49 ! quint 4023: Property ='VertRef' ':' HorizPosition /
! 4024: 'HorizRef' ':' VertPosition /
1.6 cvs 4025: 'VertPos' ':' VPos /
4026: 'HorizPos' ':' HPos /
1.49 ! quint 4027: 'Float' ':' FloatInherit /
! 4028: 'Clear' ':' ClearInherit /
1.6 cvs 4029: 'Height' ':' Dimension /
4030: 'Width' ':' Dimension /
4031: 'VertOverflow' ':' Boolean /
1.1 cvs 4032: 'HorizOverflow' ':' Boolean /
1.26 cvs 4033: 'MarginTop' ':' MarginWidth /
4034: 'MarginRight' ':' MarginWidth /
4035: 'MarginBottom' ':' MarginWidth /
4036: 'MarginLeft' ':' MarginWidth /
4037: 'PaddingTop' ':' PaddingWidth /
4038: 'PaddingRight' ':' PaddingWidth /
4039: 'PaddingBottom' ':' PaddingWidth /
4040: 'PaddingLeft' ':' PaddingWidth /
4041: 'BorderTopWidth' ':' BorderWidth /
4042: 'BorderRightWidth' ':' BorderWidth /
4043: 'BorderBottomWidth' ':' BorderWidth /
4044: 'BorderLeftWidth' ':' BorderWidth /
4045: 'BorderTopColor' ':' BorderColor /
4046: 'BorderRightColor' ':' BorderColor /
4047: 'BorderBottomColor' ':' BorderColor /
4048: 'BorderLeftColor' ':' BorderColor /
4049: 'BorderTopStyle' ':' BorderStyle /
4050: 'BorderRightStyle' ':' BorderStyle /
4051: 'BorderBottomStyle' ':' BorderStyle /
4052: 'BorderLeftStyle' ':' BorderStyle .
1.6 cvs 4053: 'LineSpacing' ':' DistanceInherit /
4054: 'Indent' ':' DistanceInherit /
4055: 'Adjust' ':' AdjustInherit /
4056: 'Hyphenate' ':' BoolInherit /
1.40 quint 4057: 'Direction' ':' DirInherit /
1.43 quint 4058: 'UnicodeBidi' ':' BidiInherit /
1.6 cvs 4059: 'PageBreak' ':' Boolean /
4060: 'LineBreak' ':' Boolean /
4061: 'InLine' ':' Boolean /
4062: 'NoBreak1' ':' AbsDist /
4063: 'NoBreak2' ':' AbsDist /
4064: 'Gather' ':' Boolean /
4065: 'Visibility' ':' NumberInherit /
4066: 'Size' ':' SizeInherit /
4067: 'Font' ':' NameInherit /
4068: 'Style' ':' StyleInherit /
1.23 cvs 4069: 'Weight' ':' WeightInherit /
1.6 cvs 4070: 'Underline' ':' UnderLineInherit /
4071: 'Thickness' ':' ThicknessInherit /
4072: 'Depth' ':' NumberInherit /
4073: 'LineStyle' ':' LineStyleInherit /
4074: 'LineWeight' ':' DistanceInherit /
4075: 'FillPattern' ':' NameInherit /
4076: 'Background' ':' NameInherit /
1.13 cvs 4077: 'Foreground' ':' NameInherit /
1.47 quint 4078: 'Opacity' ':' OpacityInherit /
4079: 'FillOpacity' ':' OpacityInherit /
4080: 'StrokeOpacity' ':' OpacityInherit /
1.6 cvs 4081: 'Content' ':' VarConst .
1.1 cvs 4082: PresFunc = Creation '(' BoxID ')' /
4083: 'Line' /
4084: 'NoLine' /
4085: 'Page' '(' BoxID ')' /
1.13 cvs 4086: 'Copy' '(' BoxTypeToCopy ')' /
4087: 'ShowBox' /
1.18 cvs 4088: 'BackgroundPicture' ':' FileName /
4089: 'PictureMode' ':' PictMode /</pre>
4090: </div>
4091:
4092: <div class="subsection">
1.37 cvs 4093: <h3><a name="sectc4216" id="sectc4216">Box axes</a></h3>
1.18 cvs 4094:
1.30 cvs 4095: <p>The position of the middle axes <tt>VMiddle</tt> and <tt>HMiddle</tt> in
1.1 cvs 4096: relation to their box is always calculated automatically as a function of the
1.37 cvs 4097: height and width of the box and is not specified by the presentation rules.
4098: In the presentation schema, these middle axes are used only to position their
4099: box with respect to another by specifying the distance between the middle
4100: axis and an axis or a side of another box (see the <a
4101: href="#sectc4218">relative position</a>).</p>
4102:
4103: <p>The reference axes of a box are also used to position their box in
4104: relation to another, but in contrast to the middle axes, the presentation
4105: schema must make their position explicit, either in relation to a side or the
4106: middle axis of the box itself, or in relation to an axis of an enclosed
4107: box.</p>
1.30 cvs 4108:
1.37 cvs 4109: <p>Only boxes of base elements have predefined reference axes. For character
1.1 cvs 4110: string boxes, the horizontal reference axis is the baseline of the characters
4111: (the line which passes immediately under the upper-case letters, ignoring the
4112: letter Q) and the vertical reference axis is at the left edge of the first
1.18 cvs 4113: character of the string.</p>
1.30 cvs 4114:
1.37 cvs 4115: <p>The positions of a box's reference axes are defined by the
4116: <tt>VertRef</tt> and <tt>HorizRef</tt> rules which specify the <a
4117: href="#distance">distance</a> between the reference axis and an axis or
4118: parallel side of the same box or of an enclosed box.</p>
1.49 ! quint 4119: <pre> 'VertRef' ':' HorizPosition
! 4120: 'HorizRef' ':' VertPosition</pre>
1.30 cvs 4121:
1.18 cvs 4122: <blockquote class="example">
1.30 cvs 4123: <p><strong>Example:</strong></p>
4124:
4125: <p>If, in the structure schema for mathematical formulas, the fraction
4126: element is defined by</p>
4127: <pre>Fraction = BEGIN
1.1 cvs 4128: Numerator = Expression;
4129: Denominator = Expression;
1.18 cvs 4130: END;</pre>
1.30 cvs 4131:
4132: <p>then the horizontal reference axis of the fraction can be positioned on
4133: top of the denominator by the rule:</p>
4134: <pre>Fraction :
1.1 cvs 4135: BEGIN
4136: HorizRef : Enclosed Denominator . Top;
4137: ...
1.18 cvs 4138: END;</pre>
1.30 cvs 4139:
4140: <p>To put the horizontal reference axis of a column at its middle:</p>
4141: <pre>Column :
1.1 cvs 4142: BEGIN
4143: HorizRef : * . HMiddle;
4144: ...
1.18 cvs 4145: END;</pre>
4146: </blockquote>
4147: </div>
1.1 cvs 4148:
1.18 cvs 4149: <div class="subsection">
1.37 cvs 4150: <h3><a name="sectc4217" id="sectc4217">Distance units</a></h3>
1.1 cvs 4151:
1.30 cvs 4152: <p>Some distances and dimensions appear in many rules of a presentation
4153: schema, especially in position rules (<tt>VertPos, HorizPos</tt>), in extent
4154: rules for boxes (<tt>Height, Width</tt>), in rules defining lines
1.37 cvs 4155: (<tt>LineSpacing, Indent</tt>), in rules controlling pagination
4156: (<tt>NoBreak1, NoBreak2</tt>) and in rules specifying the thickness of
4157: strokes (<tt>LineWeight</tt>).</p>
1.30 cvs 4158:
4159: <p>In all these rules, the distance or extent can be expressed</p>
4160: <ul>
4161: <li>either in relative units, which depend on the size of the characters in
4162: the current font: height of the element's font or height of the letter
4163: 'x',</li>
1.37 cvs 4164: <li>or in absolute units: centimeter, millimeter, inch, typographer's
4165: point, pica or pixel.</li>
1.30 cvs 4166: </ul>
4167:
1.37 cvs 4168: <p>Units can be chosen freely. Thus, it is possible to use relative units in
1.30 cvs 4169: one rule, centimeters in the next rule, and typographer's points in
4170: another.</p>
4171:
1.37 cvs 4172: <p>Absolute units are used to set rigid rules for the appearance of
4173: documents. In contrast, relative units allow changes of scale. The editor
4174: lets the value of relative units be changed dynamically. Such changes affect
4175: every box using relative units simultaneously and in the same proportion.
4176: Changing the value of the relative units affects the size of the characters
4177: and graphical elements, and the size of the boxes and the distances between
4178: them.</p>
4179:
4180: <p>A <a name="distance" id="distance">distance</a> or extent is specified by
4181: a number, which may be followed by one or more spaces and a units keyword.
4182: When there is no units keyword, the number specifies the number of relative
4183: units, where a relative unit is the height of a character in the current font
4184: (an em). When the number is followed by a units keyword, the keyword
4185: indicates the type of absolute units:</p>
1.18 cvs 4186: <ul>
1.40 quint 4187: <li><tt>em</tt> : height of the element's font,</li>
4188: <li><tt>ex</tt> : height of the letter 'x',</li>
4189: <li><tt>cm</tt> : centimeter,</li>
4190: <li><tt>mm</tt> : millimeter,</li>
4191: <li><tt>in</tt> : inch (1 in = 2.54 cm),</li>
4192: <li><tt>pt</tt> : point (1 pt = 1/72 in),</li>
4193: <li><tt>pc</tt> : pica (1 pc = 12 pt),</li>
4194: <li><tt>px</tt> : pixel.</li>
1.18 cvs 4195: </ul>
1.30 cvs 4196:
4197: <p>Whatever the chosen unit, relative or absolute, the number is not
1.37 cvs 4198: necessarily an integer and may be expressed in fixed point notation (using
4199: the American convention of a period to express the decimal point).</p>
1.30 cvs 4200:
1.37 cvs 4201: <p>If the distance appears in a presentation rule for a numeric attribute,
4202: the number can be replaced by the name of an attribute. In this case, the
4203: value of the attribute is used. Obviously, the attribute name cannot be
4204: followed by a decimal point and a fractional part, but it can be followed a
4205: units keyword. However, the choice of units is limited to em, ex, pt and
4206: px.</p>
1.18 cvs 4207: <pre> Distance = [ Sign ] AbsDist .
1.1 cvs 4208: Sign ='+' / '-' .
4209: AbsDist = IntegerOrAttr [ '.' DecimalPart ]
4210: [ Unit ].
4211: IntegerOrAttr = IntegerPart / AttrID .
4212: IntegerPart = NUMBER .
4213: DecimalPart = NUMBER .
4214: Unit ='em' / 'ex' / 'cm' / 'mm' / 'in' / 'pt' /
1.18 cvs 4215: 'pc' / 'px' / '%' .</pre>
1.30 cvs 4216:
1.18 cvs 4217: <blockquote class="example">
1.30 cvs 4218: <p><strong>Example:</strong></p>
4219:
4220: <p>The following rules specify that a box has a height of 10.5 centimeters
4221: and a width of 5.3 ems:</p>
4222: <pre>Height : 10.5 cm;
1.18 cvs 4223: Width : 5.3;</pre>
4224: </blockquote>
4225: </div>
1.1 cvs 4226:
1.18 cvs 4227: <div class="subsection">
1.37 cvs 4228: <h3><a name="sectc4218" id="sectc4218">Relative positions</a></h3>
1.1 cvs 4229:
1.37 cvs 4230: <p>The positioning of boxes uses the eight axes and sides, the sides
4231: generally being used to define the juxtapositioning (vertical or horizontal)
4232: of boxes, the middle axes being used to define centering, and the reference
4233: axes being used for alignment.</p>
4234:
4235: <p>Two rules allow a box to be placed relative to other boxes. The
4236: <tt>VertPos</tt> rule positions the box vertically. The <tt>HorizPos</tt>
4237: rule positions the box horizontally. It is possible that a box's position
4238: could be entirely determined by other boxes positioned relative to it. In
4239: this case, the position is implicit and the word <tt>nil</tt> can be used to
4240: specify that no position rule is needed. Otherwise, an explicit rule must be
1.18 cvs 4241: given by indicating the axis or side which defines the position of the box,
4242: followed by an equals sign and the distance between between this axis or side
1.37 cvs 4243: and a parallel axis or side of another box, called the reference box. The box
1.18 cvs 4244: for which the rule is written will be positioned relative to the reference
4245: box.</p>
4246: <pre> 'VertPos' ':' VPos
1.6 cvs 4247: 'HorizPos' ':' HPos
4248: HPos = 'nil' / VertAxis '=' HorizPosition
4249: [ 'UserSpecified' ].
4250: VPos = 'nil' / HorizAxis '=' VertPosition
4251: [ 'UserSpecified' ].
1.1 cvs 4252: VertAxis = 'Left' / 'VMiddle' / 'VRef' / 'Right' .
1.18 cvs 4253: HorizAxis = 'Top' / 'HMiddle' / 'HRef' / 'Bottom' .</pre>
1.30 cvs 4254:
1.37 cvs 4255: <p>The reference box is an adjacent box: enclosing, enclosed or adjacent.
4256: When a rule is associated with a reference type attribute (and only in this
4257: case), it can be a box of the element designated by the attribute. The
4258: reference box can be either a presentation box previously defined in the
4259: <tt>BOXES</tt> section of the schema and created by a creation function, or
4260: the box associated with a structured element.</p>
4261:
4262: <p>The structural position of the reference box (relative to the box for
4263: which the rule is being written) is indicated by a keyword:
4264: <tt>Enclosing</tt>, <tt>Enclosed</tt>, or, for sibling boxes,
4265: <tt>Previous</tt> or <tt>Next</tt>. The reference attributes, or presentation
4266: boxes created by a reference attribute, the <tt>Referred</tt> keyword may be
4267: used to designate the element which the reference points to. The keyword
4268: <tt>Creator</tt> can be used in rules for presentation boxes to designate the
4269: box of the element which created the presentation box. Finally, the
4270: <tt>Root</tt> keyword can be used to designate the root of the document.</p>
1.30 cvs 4271:
4272: <p>When the keyword is ambiguous, it is followed by the name of an element
4273: type or presentation box which resolves the ambiguity (the <tt>Creator</tt>
1.37 cvs 4274: and <tt>Root</tt> keywords are never ambiguous). If this name is not given,
1.30 cvs 4275: then the first box encountered is used as the reference box. It is also
4276: possible to use just the name of an element type or presentation box without
1.37 cvs 4277: an initial keyword. In this case, a sibling having that name will be used. If
1.30 cvs 4278: the name is preceded by the keyword <tt>NOT</tt>, then the reference box will
4279: be the first box whose type is not the named one.</p>
4280:
4281: <p>In place of the box or type name, the keywords <tt>AnyElem</tt>,
1.18 cvs 4282: <tt>AnyBox</tt> and <tt>ElemWithAttr</tt> can be used, representing
1.17 cvs 4283: respectively, any structured element box, any presentation box, and the box
4284: corresponding to any structured element having a particular attribute,
4285: whatever its value; the name of this attribute must follow the keyword
1.18 cvs 4286: <tt>ElemWithAttr</tt>.</p>
1.30 cvs 4287:
4288: <p>A type name may be preceded by a star in order to resolve the ambiguity in
4289: the special case where the structure schema defines an <a
1.18 cvs 4290: href="#sectd3284">inclusion</a> without expansion (or with partial expansion)
1.37 cvs 4291: of the same type as an element of the scheme. For mark pairs (and only for <a
1.18 cvs 4292: href="#sectd3285">mark pairs</a>) the type name <em>must</em> be preceded by
4293: the <tt>First</tt> or <tt>Second</tt> keyword, which indicates which of the
1.37 cvs 4294: two marks of the pair should be used as the reference box.</p>
1.30 cvs 4295:
4296: <p>The star character ('<tt>*</tt>') used alone designates the box to which
1.37 cvs 4297: the rule applies (in this case, it is obviously useless to specify the type
4298: of the reference box).</p>
1.30 cvs 4299:
1.37 cvs 4300: <p>The keywords <tt>Enclosing</tt> and <tt>Enclosed</tt> can be used no
4301: matter what constructor defines the type to which the rule applies. When
4302: applied to the element which represents the entire document,
4303: <tt>Enclosing</tt> designates the window or page in which the document's
4304: image is displayed for the view to which the rule applies. A box or type name
4305: without a keyword is used for aggregate elements and designates another
4306: element of the same aggregate. It can also be used to designate a
4307: presentation or page layout box. The keywords <tt>Previous</tt> and
4308: <tt>Next</tt> are primarily used to denote list elements, but can also be
4309: used to denote elements of an aggregate.</p>
4310:
4311: <p>In the position rule, the structural position relative to the reference
4312: box is followed, after a period, by the name of an axis or side. The rule
4313: specifies its node's position as being some distance from this axis or side
4314: of the reference box. If this distance is zero, then the distance does not
4315: appear in the rule. Otherwise, it does appear as a positive or negative
1.30 cvs 4316: number (the sign is required for negative numbers). The sign takes into
4317: account the orientation of the coordinate axes: for top to bottom for the
1.37 cvs 4318: vertical axis and from left to right for the horizontal axis. Thus, a
1.30 cvs 4319: negative distance in a vertical position indicates that the side or axis
4320: specified in the rule is above the side or axis of the reference box.</p>
4321:
1.37 cvs 4322: <p>The distance can be followed by the <tt>UserSpecified</tt> keyword (even
4323: if the distance is nil and does not appear, the <tt>UserSpecified</tt>
4324: keyword can be used). It indicates that when the element to which the rule
4325: applies is being created, the editor will ask the user to specify the
4326: distance himself, using the mouse. In this case, the distance specified in
4327: the rule is a default distance which is suggested to the user but can be
4328: modified. The <tt>UserSpecified</tt> keyword can be used either in the
4329: vertical position rule, the horizontal position rule, or both.</p>
1.18 cvs 4330: <pre> VertPosition = Reference '.' HorizAxis [ Distance ] .
1.1 cvs 4331: HorizPosition = Reference '.' VertAxis [ Distance ] .
4332: Reference ='Enclosing' [ BoxTypeNot ] /
4333: 'Enclosed' [ BoxTypeNot ] /
4334: 'Previous' [ BoxTypeNot ] /
4335: 'Next' [ BoxTypeNot ] /
4336: 'Referred' [ BoxTypeNot ] /
4337: 'Creator' /
4338: 'Root' /
4339: '*' /
4340: BoxOrType .
4341: BoxOrType = BoxID /
4342: [ '*' ] [ FirstSec ] ElemID /
1.17 cvs 4343: 'AnyElem' / 'AnyBox' /
4344: 'ElemWithAttr' AttrID .
1.18 cvs 4345: BoxTypeNot = [ 'NOT' ] BoxOrType .</pre>
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>If a <a name="expos1" id="expos1">report</a> is defined by the following
4351: structure schema:</p>
1.30 cvs 4352: <pre>Report = BEGIN
1.6 cvs 4353: Title = Text;
4354: Summary = Text;
4355: Keywords = Text;
4356: ...
1.18 cvs 4357: END;</pre>
1.30 cvs 4358:
4359: <p>then the presentation schema could contain the rules:</p>
4360: <pre>Report : BEGIN
1.6 cvs 4361: VertPos : Top = Enclosing . Top;
4362: HorizPos : Left = Enclosing . Left;
4363: ...
1.18 cvs 4364: END;</pre>
1.30 cvs 4365:
1.37 cvs 4366: <p>These rules place the <a name="reportexample"
4367: id="reportexample">report</a> in the upper left corner of the enclosing
4368: box, which is the window in which the document is being edited.</p>
1.30 cvs 4369: <pre>Title : BEGIN
1.6 cvs 4370: VertPos : Top = Enclosing . Top + 1;
4371: HorizPos : VMiddle = Enclosing . VMiddle;
4372: ...
1.18 cvs 4373: END;</pre>
1.30 cvs 4374:
1.37 cvs 4375: <p>The top of the title is one line (a line has the height of the
4376: characters of the title) from the top of the report, which is also the top
4377: of the editing window. The title is centered horizontally in the window
4378: (see <a href="#posdim">figure</a>).</p>
1.30 cvs 4379: <pre>Summary : BEGIN
1.1 cvs 4380: VertPos : Top = Title . Bottom + 1.5;
4381: HorizPos : Left = Enclosing . Left + 2 cm;
4382: ...
1.18 cvs 4383: END;</pre>
1.30 cvs 4384:
1.37 cvs 4385: <p>The top of the summary is place a line and a half below the bottom of
4386: the title and is shifted two centimeters from the side of the window.</p>
1.18 cvs 4387: </blockquote>
1.30 cvs 4388:
1.18 cvs 4389: <blockquote class="example">
1.30 cvs 4390: <p><strong>Example:</strong></p>
4391:
1.37 cvs 4392: <p>Suppose there is a <a name="expos2" id="expos2">Design</a> logical
4393: structure which contains graphical elements:</p>
1.30 cvs 4394: <pre>Design = LIST OF (ElemGraph = GRAPHICS);</pre>
4395:
4396: <p>The following rules allow the user to freely choose the position of each
4397: element when it is created:</p>
4398: <pre>ElemGraph =
1.1 cvs 4399: BEGIN
4400: VertPos : Top = Enclosing . Top + 1 cm UserSpecified;
4401: HorizPos: Left = Enclosing . Left UserSpecified;
4402: ...
1.18 cvs 4403: END;</pre>
1.30 cvs 4404:
4405: <p>Thus, when a graphical element is created, its default placement is at
4406: the left of the window and 1 cm from the top, but the user can move it
4407: immediately, simply by moving the mouse.</p>
1.18 cvs 4408: </blockquote>
4409: </div>
1.1 cvs 4410:
1.18 cvs 4411: <div class="subsection">
1.49 ! quint 4412: <h3><a name="Floats" id="Floats">Floats</a></h3>
! 4413:
! 4414: <p>Another way to set the position of a box is to make it a floating box. The
! 4415: notion of a floating box is the same as in CSS2. Refer to the <a
! 4416: href="http://www.w3.org/TR/REC-CSS2/visuren.html#floats">relevant section of
! 4417: the CSS2 Recommendation</a> for the details. The <code>Float</code> and
! 4418: <code>Clear</code> rules allow to control how floating boxes behave. The
! 4419: values of these rules are the same as in CSS2. Inheritance is indicated by
! 4420: <code>Enclosing =</code></p>
! 4421: <pre> 'Float' ':' FloatInherit
! 4422: 'Clear' ':' ClearInherit
! 4423: FloatInherit = Link '=' / 'Left' / 'Right' / 'None' .
! 4424: ClearInherit = Link '=' / 'None' / 'Left' / 'Right' / 'Both' .</pre>
! 4425: </div>
! 4426:
! 4427: <div class="subsection">
1.37 cvs 4428: <h3><a name="sectc4219" id="sectc4219">Box extents</a></h3>
1.1 cvs 4429:
1.30 cvs 4430: <p>The extents (height and width) of each box are defined by the two rules
1.37 cvs 4431: <tt>Height</tt> and <tt>Width</tt>. There are three types of extents: fixed,
1.18 cvs 4432: relative, and elastic.</p>
1.1 cvs 4433:
1.18 cvs 4434: <div class="subsubsection">
1.37 cvs 4435: <h4><a name="sectd42191" id="sectd42191">Fixed extents</a></h4>
1.1 cvs 4436:
1.30 cvs 4437: <p>A fixed dimension sets the height or width of the box independently of all
1.37 cvs 4438: other boxes. It is expressed in <a href="#sectc4217">distance units</a>. The
1.18 cvs 4439: extent can be followed by the <tt>UserSpecified</tt> keyword which indicates
1.1 cvs 4440: that when the element to which the rule applies is being created, the editor
1.37 cvs 4441: will ask the user to specify the extent himself, using the mouse. In this
1.1 cvs 4442: case, the extent specified in the rule is a default extent which is suggested
1.37 cvs 4443: to the user but can be modified. The <tt>UserSpecified</tt> keyword can be
1.18 cvs 4444: used either in the <tt>Height</tt> rule, the <tt>Width</tt> rule, or both.</p>
1.30 cvs 4445:
4446: <p>A fixed extent rule can be ended by the <tt>Min</tt> keyword, which
4447: signifies that the indicated value is a minimum, and that, if the contents of
4448: the box require it, a larger extent is possible.</p>
1.18 cvs 4449: <pre> 'Height' ':' Dimension
1.1 cvs 4450: 'Width' ':' Dimension
4451: Dimension = AbsDist [ 'UserSpecified' ] [ 'Min' ] /
1.18 cvs 4452: ...</pre>
1.30 cvs 4453:
1.18 cvs 4454: <blockquote class="example">
1.30 cvs 4455: <p><strong>Example:</strong></p>
4456:
4457: <p>Continuing with the <a href="#expos2">previous example</a>, it is
4458: possible to allow the user to choose the size of each graphical element as
4459: it is created:</p>
4460: <pre>ElemGraph : BEGIN
1.6 cvs 4461: Width : 2 cm UserSpecified;
1.1 cvs 4462: Height : 1 cm UserSpecified;
4463: ...
1.18 cvs 4464: END;</pre>
1.30 cvs 4465:
4466: <p>Thus, when a graphical element is create, it is drawn by default with a
4467: width of 2 cm and a height of 1 cm, but the user is free to resize it
4468: immediately with the mouse.</p>
4469: <pre>Summary : BEGIN
1.1 cvs 4470: Height : 5 cm Min;
4471: ...
4472: END;
4473: Keywords : BEGIN
4474: VertPos : Top = Summary . Bottom;
4475: ...
1.18 cvs 4476: END;</pre>
4477: </blockquote>
4478: </div>
1.1 cvs 4479:
1.18 cvs 4480: <div class="subsubsection">
1.37 cvs 4481: <h4><a name="sectd42192" id="sectd42192">Relative extents</a></h4>
1.30 cvs 4482:
4483: <p>A relative extent determines the extent as a function of the extent of
4484: another box, just as a relative position places a box in relation to another.
4485: The reference box in an extent rule is designated using the same syntax as is
1.37 cvs 4486: used in a relative position rule. It is followed by a period and a
1.30 cvs 4487: <tt>Height</tt> or <tt>Width</tt> keyword, depending on the extent being
1.37 cvs 4488: referred to. Next comes the relation between the extent being defined and the
4489: extent of the reference box. This relation can be either a percentage or a
1.30 cvs 4490: difference.</p>
1.1 cvs 4491:
1.37 cvs 4492: <p>A percentage is indicated by a star (the multiplication symbol) followed
4493: by the numeric percentage value (which may be greater than or less than 100)
4494: and the percent (`%') character. A difference is simply indicated by a signed
1.18 cvs 4495: difference.</p>
1.30 cvs 4496:
4497: <p>If the rule appears in the presentation rules of a numeric attribute, the
1.1 cvs 4498: percentage value can be replaced by the name of the attribute. This attribute
1.37 cvs 4499: is then used as a percentage. The attribute can also be used as part of a <a
1.18 cvs 4500: href="#distance">difference</a>.</p>
1.30 cvs 4501:
4502: <p>Just as with a fixed extent, a relative extent rule can end with the
1.18 cvs 4503: <tt>Min</tt> keyword, which signifies that the extent is a minimum and that,
4504: if the contents of the box require it, a larger extent is possible.</p>
1.30 cvs 4505:
4506: <p>A special case of relative extent rules is:</p>
1.18 cvs 4507: <pre>Height : Enclosed . Height;</pre>
1.30 cvs 4508:
4509: <p>or</p>
1.18 cvs 4510: <pre>Width : Enclosed . Width;</pre>
1.30 cvs 4511:
4512: <p>which specifies that the box has a height (or width) such that it encloses
4513: all the boxes which it contains, excluding boxes having a rule
4514: <tt>VertOverflow: Yes;</tt> or <tt>HorizOverflow: Yes;</tt>.</p>
4515:
4516: <p><strong>Note:</strong> character strings (type <tt>TEXT_UNIT</tt>)
4517: generally must use the sum of the widths of the characters which compose them
4518: as their width, which is expressed by the rule:</p>
1.18 cvs 4519: <pre>TEXT_UNIT :
4520: Width : Enclosed . Width;</pre>
1.30 cvs 4521:
4522: <p>If this rule is not the default <tt>Width</tt> rule, it must be given
1.18 cvs 4523: explicitly in the <tt>RULES</tt> section which defines the presentation rules
4524: of the logical elements.</p>
4525: <pre> 'Height' ':' Extent
1.1 cvs 4526: 'Width' ':' Extent
4527: Extent = Reference '.' HeightWidth [ Relation ]
4528: [ 'Min' ] / ...
4529: HeightWidth ='Height' / 'Width' .
4530: Relation ='*' ExtentAttr '%' / Distance .
4531: ExtentAttr = ExtentVal / AttrID .
1.18 cvs 4532: ExtentVal = NUMBER .</pre>
1.30 cvs 4533:
1.18 cvs 4534: <blockquote class="example">
1.30 cvs 4535: <p><strong>Example:</strong></p>
4536:
4537: <p>Completing the <a href="#expos1">above example</a>, it is possible to
4538: specify that the report takes its width from the editing window and its
4539: height from the size of its contents (this can obviously be greater than
4540: that of the window):</p>
4541: <pre>Report : BEGIN
1.1 cvs 4542: Width : Enclosing . Width;
4543: Height : Enclosed . Height;
4544: ...
1.18 cvs 4545: END;</pre>
1.30 cvs 4546:
4547: <p>Then, the following rules make the title occupy 60% of the width of the
4548: report (which is that of the window) and is broken into centered lines of
4549: this width (see the <a href="#sectc4222"><tt>Line</tt> rule</a>).</p>
4550: <pre>Title : BEGIN
1.1 cvs 4551: Width : Enclosing . Width * 60%;
4552: Height : Enclosed . Height;
4553: Line;
4554: Adjust : VMiddle;
4555: ...
1.18 cvs 4556: END;</pre>
1.30 cvs 4557:
4558: <p>The summary occupy the entire width of the window, with the exception of
4559: a 2 cm margin reserved by the horizontal position rule:</p>
4560: <pre>Summary : BEGIN
1.1 cvs 4561: Width : Enclosing . Width - 2 cm;
4562: Height : Enclosed . Height;
4563: ...
1.18 cvs 4564: END;</pre>
4565:
1.37 cvs 4566: <p>This set of rules, plus the <a href="#reportexample">position rules
4567: given above</a>, produce the layout of boxes shown in the following<a
1.30 cvs 4568: href="#posdim">figure</a>.</p>
4569:
4570: <div class="figure">
1.37 cvs 4571: <hr />
1.30 cvs 4572: <pre>-------------------------------------------------------------
1.1 cvs 4573: | Window and Report ^ |
4574: | | 1 line |
4575: | v |
4576: | ------------------------------------- |
4577: | | | |
4578: : 20% : Title : 20% :
1.30 cvs 4579: :<--------->: :<--------->:
1.1 cvs 4580: : : 60% : :
1.30 cvs 4581: : :<--------------------------------->: :
1.1 cvs 4582: | | | |
4583: | ------------------------------------- |
4584: | ^ |
4585: | | 1.5 line |
4586: | | |
4587: | v |
4588: | ---------------------------------------------------|
4589: | 2 cm | |
1.30 cvs 4590: |<------>| Summary |
1.18 cvs 4591: : : :</pre>
1.19 cvs 4592:
1.37 cvs 4593: <p align="center"><em><a name="posdim" id="posdim">Box position and
1.30 cvs 4594: extent</a><em></em></em></p>
1.37 cvs 4595: <hr />
1.30 cvs 4596: </div>
1.18 cvs 4597: </blockquote>
4598: </div>
1.1 cvs 4599:
1.18 cvs 4600: <div class="subsubsection">
1.37 cvs 4601: <h4><a name="sectd42193" id="sectd42193">Elastic extents</a></h4>
1.1 cvs 4602:
1.37 cvs 4603: <p>The last type of extent is the elastic extent. Either one or both extents
4604: can be elastic. A box has an elastic extent when two opposite sides are
1.30 cvs 4605: linked by distance constraints to two sides or axes of other boxes.</p>
4606:
4607: <p>One of the sides of the elastic box is linked by a position rule
1.37 cvs 4608: (<tt>VertPos</tt> or <tt>HorizPos</tt>) to a neighboring box. The other side
1.18 cvs 4609: is link to another box by a <tt>Height</tt> or <tt>Width</tt> rule, which
1.37 cvs 4610: takes the same form as the position rule. For the elastic box itself, the
1.1 cvs 4611: notions of sides (left or right, top or bottom) are fuzzy, since the movement
4612: of either one of the two reference boxes can, for example, make the left side
1.37 cvs 4613: of the elastic box move to the right of its right side. This is not
4614: important. The only requirement is that the two sides of the elastic box used
1.18 cvs 4615: in the position and extent rule are opposite sides of the box.</p>
4616: <pre> 'Height' ':' Extent
1.6 cvs 4617: 'Width' ':' Extent
1.18 cvs 4618: Extent = HPos / VPos / ...</pre>
1.30 cvs 4619:
1.18 cvs 4620: <blockquote class="example">
1.30 cvs 4621: <p><strong>Example:</strong></p>
4622:
4623: <p>Suppose we want to draw an elastic arrow or line between the middle of
1.37 cvs 4624: the bottom side of box A and the upper left corner of box B. To do this, we
1.30 cvs 4625: would define a graphics box whose upper left corner coincides with the
4626: middle of the bottom side of A (a position rule) and whose lower right
4627: corner coincides with with the upper left corner of B (dimension rules):</p>
4628: <pre>LinkedBox :
1.1 cvs 4629: BEGIN
1.6 cvs 4630: VertPos : Top = A .Bottom;
1.1 cvs 4631: HorizPos : Left = A . VMiddle;
1.6 cvs 4632: Height : Bottom = B . Top;
4633: Width : Right = B . Left;
1.18 cvs 4634: END;</pre>
4635: </blockquote>
1.30 cvs 4636:
1.18 cvs 4637: <blockquote class="example">
1.30 cvs 4638: <p><strong>Example:</strong></p>
4639:
4640: <p>The element SectionTitle creates a presentation box called SectionNum
1.37 cvs 4641: which contains the number of the section. Suppose we want to align the
4642: SectionNum and SectionTitle horizontally, have the SectionNum take its
4643: width from its contents (the section number), have the SectionTitle box
4644: begin 0.5 cm to the right of the SectionNum box and end at the right edge
4645: of its enclosing box. This would make the SectionTitle box elastic, since
4646: its width is defined by the position of its left and right sides. The
4647: following rules produce this effect:</p>
1.30 cvs 4648: <pre>SectionNum :
1.1 cvs 4649: BEGIN
4650: HorizPos : Left = Enclosing . Left;
4651: Width : Enclosed . Width;
4652: ...
4653: END;
4654:
4655: SectionTitle :
4656: BEGIN
4657: HorizPos : Left = SectionNum . Right + 0.5 cm;
4658: Width : Right = Enclosing . Right;
4659: ...
1.18 cvs 4660: END;</pre>
4661: </blockquote>
4662: </div>
4663: </div>
1.1 cvs 4664:
1.18 cvs 4665: <div class="subsection">
1.37 cvs 4666: <h3><a name="sectc4220" id="sectc4220">Overflow</a></h3>
1.1 cvs 4667:
1.48 quint 4668: <p>A box corresponding to a structural element normally contain all boxes
1.37 cvs 4669: corresponding to the elements of its subtree. However, in some cases, it
1.1 cvs 4670: could be necessary to allow a box to jut out from its parent box. Two
4671: presentation rules indicate that such an overflow is allowed, one for
1.18 cvs 4672: horizontal overflow, one for vertical overflow.</p>
1.30 cvs 4673:
4674: <p>Each of these rules is expressed by a keyword followed by a colon and the
1.18 cvs 4675: keyword <tt>Yes</tt> or <tt>No</tt>.</p>
4676: <pre> 'VertOverflow' ':' Boolean /
1.1 cvs 4677: 'HorizOverflow' ':' Boolean .
1.18 cvs 4678: Boolean = 'Yes' / 'No' .</pre>
4679: </div>
1.1 cvs 4680:
1.48 quint 4681: <div>
4682: <h3><a name="Margins" id="Margins">Margins, Padding and Borders</a></h3>
1.30 cvs 4683:
1.48 quint 4684: <p>Boxes (element boxes and presentation boxes as well) may have margins,
4685: padding and borders, exactly as in CSS. A set of presentation rules allow to
4686: control the width of margins, padding and borders along the four edges of
4687: boxes. Other rules determine the color and style of borders. Refer to the
4688: CSS2 specification for more details.</p>
1.26 cvs 4689: <pre> 'MarginTop' ':' MarginWidth /
4690: 'MarginRight' ':' MarginWidth /
4691: 'MarginBottom' ':' MarginWidth /
4692: 'MarginLeft' ':' MarginWidth /
4693: 'PaddingTop' ':' PaddingWidth /
4694: 'PaddingRight' ':' PaddingWidth /
4695: 'PaddingBottom' ':' PaddingWidth /
4696: 'PaddingLeft' ':' PaddingWidth /
4697: 'BorderTopWidth' ':' BorderWidth /
4698: 'BorderRightWidth' ':' BorderWidth /
4699: 'BorderBottomWidth' ':' BorderWidth /
4700: 'BorderLeftWidth' ':' BorderWidth /
4701: 'BorderTopColor' ':' BorderColor /
4702: 'BorderRightColor' ':' BorderColor /
4703: 'BorderBottomColor' ':' BorderColor /
4704: 'BorderLeftColor' ':' BorderColor /
4705: 'BorderTopStyle' ':' BorderStyle /
4706: 'BorderRightStyle' ':' BorderStyle /
4707: 'BorderBottomStyle' ':' BorderStyle /
4708: 'BorderLeftStyle' ':' BorderStyle .
4709:
4710: MarginWidth = InheritParent / 'Auto' / Distance .
4711: PaddingWidth = InheritParent / Distance .
4712: BorderWidth = InheritParent / 'Thin' / 'Medium' / 'Thick' / Distance .
4713: BorderColor = InheritParent / 'Transparent' / 'Foreground' /
4714: ColorName .
4715: BorderStyle = InheritParent /
4716: 'None' / 'Hidden' / 'Dotted' / 'Dashed' / 'Solid' /
4717: 'Double' / 'Groove' / 'Ridge' / 'Inset' / 'Outset' .
1.27 cvs 4718: InheritParent = 'Enclosing' '=' / 'Creator' '=' .
1.26 cvs 4719: ColorName = NAME .</pre>
1.48 quint 4720: </div>
1.26 cvs 4721:
1.18 cvs 4722: <div class="subsection">
1.37 cvs 4723: <h3><a name="sectc4221" id="sectc4221">Inheritance</a></h3>
1.1 cvs 4724:
1.37 cvs 4725: <p>A presentation property can be defined by reference to the same property
4726: of another box in the tree of boxes. These structural links are expressed by
4727: kinship. The reference box can be that of the element immediately above in
1.18 cvs 4728: the structure (<tt>Enclosing</tt>), two levels above (<tt>GrandFather</tt>),
4729: immediately below (<tt>Enclosed</tt>) or immediately before
1.37 cvs 4730: (<tt>Previous</tt>). In the case of a presentation box, and only in that
1.1 cvs 4731: case, the reference box may be the element which created the presentation box
1.18 cvs 4732: (<tt>Creator</tt>).</p>
1.30 cvs 4733:
4734: <p>Kinship is expressed in terms of the logical structure of the document and
1.37 cvs 4735: not in terms of the tree of boxes. The presentation box cannot transmit any
1.34 cvs 4736: of their properties by inheritance; only structured element boxes can do so.
1.37 cvs 4737: As an example, consider an element B which follows an element A in the
4738: logical structure. The element B creates a presentation box P in front of
4739: itself, using the <tt>CreateBefore</tt> rule (see the <a
4740: href="#sectc4232">creation rules</a>). If element B's box inherits its
4741: character style using the <tt>Previous</tt> kinship operation, it gets its
4742: character style from A's box, not from P's box. Inheritance works differently
4743: for positions and extents, which can refer to presentation boxes.</p>
1.30 cvs 4744:
1.34 cvs 4745: <p>The inherited property value can be the same as that of the reference box.
1.37 cvs 4746: This is indicated by an equals sign. However, for numeric properties, a
1.1 cvs 4747: different value can be obtained by adding or subtracting a number from the
1.37 cvs 4748: reference box's property value. Addition is indicated by a plus sign before
4749: the number, while subtraction is specified with a minus sign. The value of a
1.34 cvs 4750: property can also be given a maximum (if the sign is a plus) or minimum (if
1.18 cvs 4751: the sign is a minus).</p>
1.30 cvs 4752:
4753: <p>If the rule is being applied to a numeric attribute, the number to add or
1.37 cvs 4754: subtract can be replaced by the attribute name. The value of a maximum or
4755: minimum may also be replaced by an attribute name. In these cases, the value
1.18 cvs 4756: of the attribute is used.</p>
4757: <pre> Inheritance = Kinship InheritedValue .
1.6 cvs 4758: Kinship ='Enclosing' / 'GrandFather' / 'Enclosed' /
4759: 'Previous' / 'Creator' .
1.1 cvs 4760: InheritedValue ='+' PosIntAttr [ 'Max' maximumA ] /
1.6 cvs 4761: '-' NegIntAttr [ 'Min' minimumA ] /
4762: '=' .
4763: PosIntAttr = PosInt / AttrID .
4764: PosInt = NUMBER .
4765: NegIntAttr = NegInt / AttrID .
4766: NegInt = NUMBER .
4767: maximumA = maximum / AttrID .
4768: maximum = NUMBER .
4769: minimumA = minimum / AttrID .
1.18 cvs 4770: minimum = NUMBER .</pre>
1.30 cvs 4771:
1.36 cvs 4772: <p>The properties which can be obtained by inheritance are hyphenation,
1.43 quint 4773: writing direction, Unicode-bidi, interline spacing, character font (font
4774: family), font style, font size, visibility, indentation, underlining,
4775: alignment of text, stacking order of objects, the style and thickness of
4776: lines, fill pattern and the colors of lines and characters.</p>
1.18 cvs 4777: </div>
1.1 cvs 4778:
1.18 cvs 4779: <div class="subsection">
1.37 cvs 4780: <h3><a name="sectc4222" id="sectc4222">Line breaking</a></h3>
1.1 cvs 4781:
1.30 cvs 4782: <p>The <tt>Line</tt> rule specifies that the contents of the box should be
4783: broken into lines: the boxes included in the box to which this rule is
4784: attached are displayed one after the other, from left to right, with their
1.37 cvs 4785: horizontal reference axes aligned so that they form a series of lines. The
1.30 cvs 4786: length of these lines is equal to the width of the box to which the
4787: <tt>Line</tt> rule is attached.</p>
4788:
4789: <p>When an included box overflows the current line, it is either carried
1.45 quint 4790: forward to the next line, broken, or left the way it is. The <a
1.18 cvs 4791: href="#sectc4223"><tt>LineBreak</tt> rule</a> is used to allow or prevent the
1.37 cvs 4792: breaking of included boxes. If the included box is not breakable but is
4793: longer than the space remaining on the line, it is left as is. When a
1.1 cvs 4794: character string box is breakable, the line is broken between words or, if
1.37 cvs 4795: necessary, by <a href="#sectd42225">hyphenating a word</a>. When a compound
4796: box is breakable, the box is transparent in regard to line breaking. The
4797: boxes included in the compound box are treated just like included boxes which
4798: have the <tt>LineBreak</tt> rule. Thus, it is possible to traverse a complete
1.18 cvs 4799: subtree of boxes to line break the text leaves of a complex structure.</p>
1.30 cvs 4800:
4801: <p>The relative position rules of the included boxes are ignored, since the
4802: boxes will be placed according to the line breaking rules.</p>
4803:
1.37 cvs 4804: <p>The <tt>Line</tt> rule does not have a parameter. The characteristics of
4805: the lines that will be constructed are determined by the
1.43 quint 4806: <tt>LineSpacing</tt>, <tt>Indent</tt>, <tt>Adjust</tt>, <tt>Hyphenate</tt>,
4807: <code>Direction</code> and <code>UnicodeBidi</code> rules. Moreover, the <a
1.37 cvs 4808: href="#insectd42226"><tt>Inline</tt> rule</a> permits the exclusion of
1.36 cvs 4809: certain elements from the line breaking process.</p>
1.30 cvs 4810:
4811: <p>When the <tt>Line</tt> rule appears in the rules sequence of a non-primary
1.37 cvs 4812: view, it applies only to that view, but when the <tt>Line</tt> rule appears
4813: in the rules sequence of the primary view, it also applies to the other views
4814: by default, except for those views which explicitly invoke the
4815: <tt>NoLine</tt> rule. Thus, the <tt>NoLine</tt> rule can be used in a
4816: non-primary view to override the primary view's <tt>Line</tt> rule. The
4817: <tt>NoLine</tt> rule must not be used with the primary view because the
4818: absence of the <tt>Line</tt> rule has the same effect. Like the <tt>Line</tt>
4819: rule, the <tt>NoLine</tt> rule does not take any parameters.</p>
1.18 cvs 4820: <pre> 'Line'
4821: 'NoLine'</pre>
4822:
4823: <div class="subsubsection">
1.37 cvs 4824: <h4><a name="sectd42221" id="sectd42221">Line spacing</a></h4>
1.18 cvs 4825:
1.30 cvs 4826: <p>The <tt>LineSpacing</tt> rule defines the line spacing to be used in the
1.37 cvs 4827: line breaking process. The line spacing is the distance between the baselines
1.1 cvs 4828: (horizontal reference axis) of the successive lines produced by the
1.37 cvs 4829: <tt>Line</tt> rule. The value of the line spacing can be specified as a
4830: constant or by inheritance. It is expressed in any of the available <a
1.18 cvs 4831: href="#sectc4217">distance units</a>.</p>
1.30 cvs 4832:
4833: <p>Inheritance allows the value to be obtained from a relative in the
4834: structure tree, either without change (an equals sign appears after the
4835: inheritance keyword), with a positive difference (a plus sign), or a negative
1.37 cvs 4836: difference (a minus sign). When the rule uses a difference, the value of the
1.30 cvs 4837: difference follows the sign and is expressed as a <a
4838: href="#sectc4217">distance</a>.</p>
1.18 cvs 4839: <pre> 'LineSpacing' ':' DistOrInherit
1.6 cvs 4840: DistOrInherit = Kinship InheritedDist / Distance .
1.18 cvs 4841: InheritedDist = '=' / '+' AbsDist / '-' AbsDist .</pre>
1.30 cvs 4842:
4843: <p>When the line spacing value (or its difference from another element) is
1.37 cvs 4844: expressed in relative units, it changes with the size of the characters.
4845: Thus, when a larger font is chosen for a part of the document, the line
4846: spacing of that part expands proportionally. In contrast, when the line
4847: spacing value is expressed in absolute units (centimeters, inches,
4848: typographer's points), it is independent of the characters, which permits the
4849: maintenance of a consistent line spacing, whatever the character font. Either
4850: approach can be taken, depending on the desired effect.</p>
1.18 cvs 4851: </div>
1.1 cvs 4852:
1.18 cvs 4853: <div class="subsubsection">
1.37 cvs 4854: <h4><a name="sectd42222" id="sectd42222">First line indentation</a></h4>
1.1 cvs 4855:
1.30 cvs 4856: <p>The <tt>Indent</tt> rule is used to specify the indentation of the first
4857: line of the elements broken into lines by the <tt>Line</tt> function. The
1.1 cvs 4858: indentation determines how far the first line of the element is shifted with
1.37 cvs 4859: respect to the other lines of the same element. It can be specified as a
4860: constant or by inheritance. The constant value is a positive integer (shifted
1.1 cvs 4861: to the right; the sign is optional), a negative integer (shifted to the left)
1.37 cvs 4862: or zero (no shift). All available <a href="#sectc4217">units</a> can be
1.18 cvs 4863: used.</p>
1.30 cvs 4864:
4865: <p>Indentation can be defined for any box, regardless of whether the box is
4866: line broken, and transmitted by inheritance to elements that are line broken.
4867: The size of the indentation is specified in the same manner as the <a
1.18 cvs 4868: href="#sectd42221">line spacing</a>.</p>
4869: <pre> 'Indent' ':' DistOrInherit</pre>
4870: </div>
1.1 cvs 4871:
1.18 cvs 4872: <div class="subsubsection">
1.37 cvs 4873: <h4><a name="sectd42223" id="sectd42223">Alignment</a></h4>
1.1 cvs 4874:
1.30 cvs 4875: <p>The alignment style of the lines constructed during line breaking is
1.37 cvs 4876: defined by the <tt>Adjust</tt> rule. The alignment value can be a constant or
4877: inherited. A constant value is specified by a keyword:</p>
1.18 cvs 4878: <ul>
1.40 quint 4879: <li><tt>Left</tt> : at the left edge,</li>
4880: <li><tt>Right</tt> : at the right edge,</li>
4881: <li><tt>VMiddle</tt> : centered</li>
4882: <li><tt>Justify</tt> : justified</li>
4883: <li><tt>LeftWithDots</tt> : at the left edge with a dotted line filling out
4884: the last line up to the right edge of the line breaking box.</li>
1.18 cvs 4885: </ul>
1.30 cvs 4886:
1.37 cvs 4887: <p>An inherited value can only be the same as that of the reference box and
4888: is specified by a kinship keyword followed by an equals sign.</p>
1.18 cvs 4889: <pre> 'Adjust' ':' AlignOrInherit
1.1 cvs 4890: AlignOrInherit = Kinship '=' / Alignment .
1.35 cvs 4891: Alignment = 'Left' / 'Right' / 'VMiddle' / 'Justify' /
1.18 cvs 4892: 'LeftWithDots' .</pre>
4893: </div>
1.1 cvs 4894:
1.18 cvs 4895: <div class="subsubsection">
1.37 cvs 4896: <h4><a name="sectd42225" id="sectd42225">Hyphenation</a></h4>
1.18 cvs 4897:
1.37 cvs 4898: <p>The <tt>Hyphenate</tt> rule indicates whether or not words should be
4899: broken by hyphenation at the end of lines. It affects the lines produced by
4900: the <tt>Line</tt> rule and contained in the box carrying the
4901: <tt>Hyphenate</tt> rule.</p>
1.30 cvs 4902:
1.34 cvs 4903: <p>The hyphenation property takes a boolean value, which can be either
1.37 cvs 4904: constant or inherited. A constant boolean value is expressed by either the
4905: <tt>Yes</tt> or the <tt>No</tt> keyword. An inherited value can only be the
1.1 cvs 4906: same as that of the reference box and is specified by a kinship keyword
1.18 cvs 4907: followed by an equals sign.</p>
4908: <pre> 'Hyphenate' ':' BoolInherit
1.1 cvs 4909: BoolInherit = Boolean / Kinship '=' .
1.18 cvs 4910: Boolean = 'Yes' / 'No' .</pre>
4911: </div>
4912:
4913: <div class="subsubsection">
1.40 quint 4914: <h4><a name="sectd422251" id="sectd422251">Writing direction</a></h4>
4915:
4916: <p>The <tt>Direction</tt> rule indicates the directionality of text: from
4917: left to right, as for latin scripts, or from right to left, as for the Arabic
1.43 quint 4918: or Hebrew scripts. This is used by the Unicode bidirectional algorithm.</p>
1.40 quint 4919:
4920: <p>The writing direction property takes either a constant value
4921: (<code>ltr</code> for left to right, or <code>rtl</code> for right to left)
4922: or it is inherited. If it is inherited, it can only be the same as that of
4923: the reference box and is specified by a kinship keyword followed by an equals
4924: sign.</p>
4925: <pre> 'Direction' ':' DirInherit
4926: DirInherit = 'ltr' / 'rtl' / Kinship '=' .</pre>
4927: </div>
4928:
1.43 quint 4929: <p>The <code>UnicodeBidi</code> rule is the equivalent of the CSS2
4930: <code>unicode-bidi</code> property. It takes the same values and acts in the
4931: same way.</p>
4932: <pre> 'Direction' ':' BidiInherit
4933: BidiInherit = 'Normal' / 'Embed' / 'Override' / Kinship '=' .</pre>
1.40 quint 4934:
4935: <div class="subsubsection">
1.37 cvs 4936: <h4><a name="sectd42226" id="sectd42226">Avoiding line breaking</a></h4>
1.18 cvs 4937:
1.37 cvs 4938: <p>The <tt>InLine</tt> rule is used to specify that a box that would
4939: otherwise participate in line breaking asked for by the <tt>Line</tt> rule of
4940: an enclosing box, instead avoids the line breaking process and positions
4941: itself according to the <tt>HorizPos</tt> and <tt>VertPos</tt> rules that
4942: apply to it. When the <tt>InLine</tt> rule applies to a box which would not
4943: be line broken, it has no effect.</p>
1.30 cvs 4944:
4945: <p>The rule is expressed by the <tt>InLine</tt> keyword followed by a colon
4946: and the keyword <tt>Yes</tt>, if the box should participate in line breaking,
1.37 cvs 4947: or the keyword <tt>No</tt>, if it should not. This is the only form possible:
4948: this rule cannot be inherited. Moreover, it can only appear in the rules of
1.1 cvs 4949: the primary view and applies to all views defined in the presentation
1.18 cvs 4950: schema.</p>
4951: <pre> 'InLine' ':' Boolean .
4952: Boolean = 'Yes' / 'No' .</pre>
1.30 cvs 4953:
1.18 cvs 4954: <blockquote class="example">
1.30 cvs 4955: <p><strong>Example:</strong></p>
4956:
4957: <p>Suppose the structure schema defines a logical attribute called
1.37 cvs 4958: <tt>New</tt> which is used to identify the passages in a document which
4959: were recently modified. It would be nice to have the presentation schema
4960: make a bar appear in the left margin next to each passage having the
4961: <tt>New</tt> attribute. A new passage can be an entire element, such as a
4962: paragraph or section, or it can be some words in the middle of a paragraph.
4963: To produce the desired effect, the <tt>New</tt> attribute is given a
4964: creation rule which generates a <tt>VerticalBar</tt> presentation box.</p>
1.30 cvs 4965:
4966: <p>When the <tt>New</tt> attribute is attached to a character string which
4967: is inside a line broken element (inside a paragraph, for example), the bar
4968: is one of the elements which participates in line breaking and it is placed
4969: normally in the current line, at the end of the character string which has
1.37 cvs 4970: the attribute. To avoid this, the <tt>InLine</tt> rule is used in the
1.30 cvs 4971: following way:</p>
4972: <pre>BOXES
1.1 cvs 4973: VerticalBar:
4974: BEGIN
4975: Content: Graphics 'l';
4976: HorizPos: Left = Root . Left;
4977: VertPos: Top = Creator . Top;
4978: Height: Bottom = Creator . Bottom;
4979: Width: 1 pt;
4980: InLine: No;
4981: ...
4982: END;
4983: ...
4984: ATTRIBUTES
4985: Nouveau:
4986: BEGIN
4987: CreateAfter(VerticalBar);
1.18 cvs 4988: END;</pre>
4989: </blockquote>
4990: </div>
4991: </div>
1.1 cvs 4992:
1.18 cvs 4993: <div class="subsection">
1.37 cvs 4994: <h3><a name="sectc4223" id="sectc4223">Page breaking and line breaking
4995: conditions</a></h3>
1.1 cvs 4996:
1.30 cvs 4997: <p>Pages are constructed by the editor in accordance with the model specified
1.37 cvs 4998: by a <a href="#sectc4233"><tt>Page</tt> rule</a>. The page model describes
1.30 cvs 4999: only the composition of the pages but does not give any rules for breaking
1.37 cvs 5000: different element types across pages. Now, it is possible that certain
5001: elements must not be cut by page breaks, while others can be cut anywhere.
5002: The <tt>PageBreak</tt>, <tt>NoBreak1</tt>, and <tt>NoBreak2</tt> rules are
5003: used to specify the conditions under which each element type can be cut.</p>
1.30 cvs 5004:
5005: <p>The <tt>PageBreak</tt> rule is used to indicate whether or not the box can
1.37 cvs 5006: be cut during the construction of pages. If cutting is authorized, the box
5007: can be cut, with one part appearing at the bottom of a page and the other
5008: part appearing at the top of the next page. The rule is formed by the
1.18 cvs 5009: <tt>PageBreak</tt> keyword followed by a colon and a constant boolean value
1.37 cvs 5010: (<tt>Yes</tt> or <tt>No</tt>). This is the only form possible: this rule
5011: cannot be inherited. Moreover, it can only appear in the rules of the primary
1.18 cvs 5012: view and applies to all views defined in the presentation schema.</p>
1.30 cvs 5013:
5014: <p>Whether objects can be cut by line breaks can be controlled in a similar
1.37 cvs 5015: way using the <tt>LineBreak</tt> rule. This rule allows the specification of
5016: whether or not the box can be cut during the construction of lines. If
1.1 cvs 5017: cutting is authorized, the box can be cut, with one part appearing at the end
1.37 cvs 5018: of a line and the other part appearing at the beginning of the next line. The
1.18 cvs 5019: rule is formed by the <tt>LineBreak</tt> keyword followed by a colon and a
1.37 cvs 5020: constant boolean value (<tt>Yes</tt> or <tt>No</tt>). This is the only form
5021: possible: this rule cannot be inherited. Moreover, it can only appear in the
5022: rules of the primary view and applies to all views defined in the
5023: presentation schema.</p>
1.18 cvs 5024: <pre> 'PageBreak' ':' Boolean .
1.1 cvs 5025: 'LineBreak' ':' Boolean .
1.18 cvs 5026: Boolean = 'Yes' / 'No' .</pre>
1.30 cvs 5027:
5028: <p>When a box can be cut by a page break, it is possible that a page break
5029: will fall an inappropriate spot, creating, for example, a widow or orphan, or
1.37 cvs 5030: separating the title of a section from the first paragraph of the section.
5031: The <tt>NoBreak1</tt> and <tt>NoBreak2</tt> rules are used to avoid this.
5032: They specify that the box of the element to which they apply cannot be cut
5033: within a certain zone at the top (<tt>NoBreak1</tt> rule) or at the bottom
5034: (<tt>NoBreak2</tt> rule). These two rules specify the height of the zones in
1.18 cvs 5035: which page breaks are prohibited.</p>
1.30 cvs 5036:
5037: <p>The <tt>NoBreak1</tt> and <tt>NoBreak2</tt> rules give the height of the
1.37 cvs 5038: zone in which page breaking is prohibited. The height is given as a constant
1.30 cvs 5039: value using any of the <a href="#sectc4217">available units</a>, absolute or
1.37 cvs 5040: relative. The value may not be inherited.</p>
1.18 cvs 5041: <pre> 'NoBreak1' ':' AbsDist .
5042: 'NoBreak2' ':' AbsDist .</pre>
1.30 cvs 5043:
1.18 cvs 5044: <blockquote class="example">
1.30 cvs 5045: <p><strong>Example:</strong></p>
5046:
5047: <p>The following rules prevent widows and orphans in a paragraph:</p>
5048: <pre>Paragraph :
1.1 cvs 5049: BEGIN
5050: NoBreak1 : 2;
5051: NoBreak2 : 2;
1.18 cvs 5052: END;</pre>
1.30 cvs 5053:
1.37 cvs 5054: <p>This rule prevents a section title from becoming separated from the
5055: first paragraph of the section by prohibiting page breaks at the beginning
5056: of the section rule:</p>
1.30 cvs 5057: <pre>Section :
1.18 cvs 5058: NoBreak1 : 1.5 cm;</pre>
1.30 cvs 5059:
5060: <p>Finally, this rule prevents a figure from being page broken in any
5061: way:</p>
5062: <pre>Figure :
1.18 cvs 5063: PageBreak : No;</pre>
5064: </blockquote>
1.30 cvs 5065:
5066: <p>The Thot editor constructs the document images displayed on the screen
1.37 cvs 5067: dynamically. As the user moves in the document or makes the document scroll
1.1 cvs 5068: in a window, the editor constructs the image to be displayed in little bits,
1.37 cvs 5069: filling the gaps which are produced in the course of these operations. It
1.1 cvs 5070: stops filling in the image when an element reaches the edge of the window in
1.37 cvs 5071: which the gap appears. If the appearance of the document is complex, it is
1.1 cvs 5072: possible that the image in incomplete, even though the edge of the window was
1.37 cvs 5073: reached. For example, an element might need to be presented to the side of
5074: the last element displayed, but its image was not constructed. The user will
1.1 cvs 5075: not know whether the element is really absent or if its image has simply not
1.18 cvs 5076: been constructed.</p>
1.30 cvs 5077:
1.37 cvs 5078: <p>The <tt>Gather</tt> rule is used to remedy this problem. When the rule
1.18 cvs 5079: <tt>Gather : Yes;</tt> is associated with an element type, the image of such
5080: elements is constructed as a block by the editor: it is never split up.</p>
1.30 cvs 5081:
5082: <p>The <tt>Gather</tt> rule may not appear in the <a href="#sectc427">default
1.37 cvs 5083: rules</a>. Elements which do not have the <tt>Gather</tt> rule are considered
5084: susceptible to being split up during display. Thus, it is not necessary to
1.18 cvs 5085: use the <tt>Gather : No;</tt> form. This rule must be used prudently and only
1.37 cvs 5086: for those elements which truly need it. If used incorrectly, it can
1.18 cvs 5087: pointlessly increase the size of the image constructed by the editor and lead
5088: to excessive memory consumption by the editor.</p>
1.30 cvs 5089:
5090: <p>Like the <tt>PageBreak</tt> and <tt>LineBreak</tt> rules, the
5091: <tt>Gather</tt> rule can only appear in rules of the primary view and applies
5092: to all views defined in the presentation schema.</p>
1.18 cvs 5093: <pre> 'Gather' ':' Boolean .</pre>
5094: </div>
1.1 cvs 5095:
1.18 cvs 5096: <div class="subsection">
1.37 cvs 5097: <h3><a name="sectc4224" id="sectc4224">Visibility</a></h3>
1.1 cvs 5098:
1.34 cvs 5099: <p>The visibility property is used to control which elements should or should
1.37 cvs 5100: not be displayed, based on context. An element can have different
5101: visibilities in different views. If an element's visibility is zero for a
5102: view, that element is not displayed in that view and does not occupy any
5103: space (its extents are zero).</p>
1.30 cvs 5104:
1.37 cvs 5105: <p>Visibility takes non-negative integer values (positive or zero). If values
1.1 cvs 5106: greater than 1 are used, they allow the user to choose a degree of visibility
1.37 cvs 5107: and, thus, to see only those boxes whose visibility property exceeds a
5108: certain threshold. This gives the user control over the granularity of the
5109: displayed pictures.</p>
1.30 cvs 5110:
1.34 cvs 5111: <p>The visibility property can be defined as a constant or by inheritance. If
1.1 cvs 5112: defined by inheritance, it cannot be based on the value of the next or
1.37 cvs 5113: previous box. Visibility can only be inherited from above.</p>
1.30 cvs 5114:
5115: <p>If it is a numeric attribute's presentation rule, the visibility can be
1.37 cvs 5116: specified by the attribute's name, in which case the value of the attribute
5117: is used.</p>
1.18 cvs 5118: <pre> 'Visibility' ':' NumberInherit
1.1 cvs 5119: NumberInherit = Integer / AttrID / Inheritance .
1.18 cvs 5120: Integer = NUMBER .</pre>
1.30 cvs 5121:
1.18 cvs 5122: <blockquote class="example">
1.30 cvs 5123: <p><strong>Example:</strong></p>
5124:
5125: <p>Suppose that only <tt>Formula</tt> elements should be displayed in the
1.37 cvs 5126: <tt>MathView</tt> view. Then, the default rules should include:</p>
1.30 cvs 5127: <pre>DEFAULT
1.18 cvs 5128: IN MathView Visibility:0;</pre>
1.30 cvs 5129:
1.31 cvs 5130: <p>which makes all elements invisible in the <tt>MathView</tt> view.
1.30 cvs 5131: However, the <tt>Formula</tt> element also has a <tt>Visibility</tt>
5132: rule:</p>
5133: <pre>Formula :
1.18 cvs 5134: IN MathView Visibility:5;</pre>
1.30 cvs 5135:
5136: <p>which makes formulas, and only formulas, visible.</p>
1.18 cvs 5137: </blockquote>
5138: </div>
1.1 cvs 5139:
1.18 cvs 5140: <div class="subsection">
1.37 cvs 5141: <h3><a name="sectc4225" id="sectc4225">Character style properties</a></h3>
1.1 cvs 5142:
1.34 cvs 5143: <p>Four properties are used to determine which characters are used to display
1.37 cvs 5144: text. They are size, font, style, and underlining.</p>
1.1 cvs 5145:
1.18 cvs 5146: <div class="subsubsection">
1.37 cvs 5147: <h4><a name="sectd42251" id="sectd42251">Character size</a></h4>
1.30 cvs 5148:
1.37 cvs 5149: <p>The size property has two effects. First, it is used to specify the actual
1.34 cvs 5150: size and distance units for boxes defined in <a href="#sectc4217">relative
1.37 cvs 5151: units</a>. Second, it defines the size of the characters contained in the
1.34 cvs 5152: box.</p>
1.1 cvs 5153:
1.30 cvs 5154: <p>As a distance or length, the size can be expressed in abstract or absolute
1.37 cvs 5155: units. It can also be inherited. If it is not inherited, it is expressed
5156: simply as an integer followed by the <tt>pt</tt> keyword, which indicates
5157: that the size is expressed in typographer's points. The absence of the
5158: <tt>pt</tt> keyword indicates that it is in abstract units in which the value
5159: 1 represents the smallest size while the value 16 is the largest size. The
5160: relationship between these abstract sizes and the real character sizes is
5161: controlled by a table which can be modified statically or even dynamically
5162: during the execution of the Thot editor.</p>
1.30 cvs 5163:
5164: <p>If the <tt>Size</tt> rule is a numeric attribute's presentation rule, the
1.34 cvs 5165: value of the size property can be specified by the attribute's name, in which
1.30 cvs 5166: case the value of the attribute is used.</p>
5167:
1.37 cvs 5168: <p><strong>Note:</strong> the only unit available for defining an absolute
5169: size is the typographer's point. Centimeters and inches may not be used.</p>
1.30 cvs 5170:
5171: <p>If the size is inherited, the rule must specify the relative from which to
5172: inherit and any percentage or difference from that relative's value. A
5173: percentage is indicated by a <tt>*</tt> followed by the value of the
5174: percentage and a <tt>%</tt>. A difference can be expressed in either
5175: typographer's points or in abstract units and the maximum or minimum size can
1.37 cvs 5176: be specified, but without specifying the unit: it is the same as was
5177: specified for the difference.</p>
1.30 cvs 5178:
5179: <p>In a numeric attribute's presentation rule, the difference in size or the
1.22 cvs 5180: percentage can be indicated by the attribute's name instead of the numeric
1.37 cvs 5181: value, which means that the attribute's value should be used as the
5182: difference or percentage. The attribute can also be used as the minimum or
5183: maximum size for a difference.</p>
1.22 cvs 5184: <pre> 'Size' ':' SizeInherit
5185: SizeInherit = SizeAttr [ 'pt' ] /
5186: Kinship InheritedSize .
5187: InheritedSize ='+' SizeAttr [ 'pt' ]
5188: [ 'Max' MaxSizeAttr ] /
5189: '-' SizeAttr [ 'pt' ]
5190: [ 'Min' MinSizeAttr ] /
5191: '*' PercentSizeAttr '%' /
5192: '=' .
5193: SizeAttr = Size / AttrID .
5194: Size = NUMBER .
5195: MaxSizeAttr = MaxSize / AttrID .
5196: MaxSize = NUMBER .
5197: MinSizeAttr = MinSize / AttrID .
5198: MinSize = NUMBER .
5199: PercentSizeAttr = PercentSize / AttrID .
5200: PercentSize = NUMBER .</pre>
1.30 cvs 5201:
1.18 cvs 5202: <blockquote class="example">
1.30 cvs 5203: <p><strong>Example:</strong></p>
5204:
5205: <p>The rule</p>
5206: <pre>Size : Enclosing - 2 pt Min 7;</pre>
5207:
5208: <p>states that the character size is 2 points less than that of the
5209: enclosing box, but that it may not be less than 7 points, whatever the
5210: enclosing box's value.</p>
5211:
5212: <p>The following rules make the text of a report be displayed with
5213: medium-sized characters (for example, size 5), while the title is displayed
5214: with larger characters and the summary is displayed with smaller
5215: characters:</p>
5216: <pre>Report :
1.1 cvs 5217: Size : 5;
5218: Title :
5219: Size : Enclosing + 2;
5220: Summary :
1.18 cvs 5221: Size : Enclosing - 1;</pre>
1.30 cvs 5222:
5223: <p>Thus, the character sizes in the entire document can be changed by
1.34 cvs 5224: changing the size property of the Report element, while preserving the
1.30 cvs 5225: relationships between the sizes of the different elements.</p>
1.18 cvs 5226: </blockquote>
5227: </div>
5228:
5229: <div class="subsubsection">
1.37 cvs 5230: <h4><a name="sectd42252" id="sectd42252">Font and character style</a></h4>
1.18 cvs 5231:
1.37 cvs 5232: <p>The <tt>Font</tt> rule determines the font family to be used to display
5233: the characters contained in the box, while the <tt>Style</tt> rule determines
5234: their style and the <tt>Weight</tt> rule determines their weight. Thot
1.23 cvs 5235: recognizes three character fonts (Times, Helvetica, and Courier), three
5236: styles: Roman, Italics, and Oblique, and two weights: Normal and Bold.</p>
1.30 cvs 5237:
5238: <p>The font family, style and weight can be specified by a named constant or
1.37 cvs 5239: can be inherited. For the name of the font family only the first character is
1.30 cvs 5240: used.</p>
5241:
5242: <p>Only identical inheritance is allowed: the box takes the same font, style
1.37 cvs 5243: or weight as the box from which it inherits. This is indicated by an equals
1.23 cvs 5244: sign after the kinship specification.</p>
5245: <pre> 'Font' ':' NameInherit /
5246: 'Style' ':' StyleInherit /
5247: 'Weight' ':' WeightInherit /
5248:
5249: NameInherit = Kinship '=' / FontName .
5250: FontName = NAME .
5251: StyleInherit = Kinship '=' /
5252: 'Roman' / 'Italics' / 'Oblique' .
5253: WeightInherit = Kinship '=' /
5254: 'Normal' / 'Bold' .</pre>
1.30 cvs 5255:
1.18 cvs 5256: <blockquote class="example">
1.30 cvs 5257: <p><strong>Example:</strong></p>
5258:
5259: <p>To specify that the summary uses the font family of the rest of the
5260: document, but in the italic style, the following rules are used:</p>
5261: <pre>Summary :
1.1 cvs 5262: BEGIN
5263: Font : Enclosing =;
5264: Style : Italics;
1.18 cvs 5265: END;</pre>
5266: </blockquote>
5267: </div>
5268:
5269: <div class="subsubsection">
1.37 cvs 5270: <h4><a name="sectd42253" id="sectd42253">Underlining</a></h4>
1.18 cvs 5271:
1.30 cvs 5272: <p>The <tt>Underline</tt> rule is used to specify if the characters contained
1.37 cvs 5273: in a box should have lines drawn on or near them. There are four underlining
1.18 cvs 5274: styles: <tt>Underlined</tt>, <tt>Overlined</tt>, <tt>CrossedOut</tt>, and
1.37 cvs 5275: <tt>NoUnderline</tt>. The <tt>Thickness</tt> rule specifies the thickness of
1.18 cvs 5276: the line, <tt>Thin</tt> or <tt>Thick</tt>.</p>
1.30 cvs 5277:
5278: <p>As with font family and style, only identical inheritance is allowed: the
1.37 cvs 5279: box has the same underlining type as the box from which it inherits the
5280: value. This is indicated by an equals sign after the kinship
5281: specification.</p>
1.18 cvs 5282: <pre> 'Underline' ':' UnderLineInherit /
1.1 cvs 5283: 'Thickness' ':' ThicknessInherit /
5284:
5285: UnderLineInherit = Kinship '=' / 'NoUnderline' /
5286: 'Underlined' /
5287: 'Overlined' / 'CrossedOut' .
1.18 cvs 5288: ThicknessInherit = Kinship '=' / 'Thick' / 'Thin' .</pre>
5289: </div>
5290: </div>
5291:
5292: <div class="subsection">
1.37 cvs 5293: <h3><a name="sectc4226" id="sectc4226">Stacking order</a></h3>
1.18 cvs 5294:
1.30 cvs 5295: <p>The <tt>Depth</tt> rule is used to define the stacking order of terminal
1.37 cvs 5296: boxes when multiple boxes at least partially overlap. This rule defines how
5297: the depth property, which is zero or a positive integer, is calculated. The
5298: depth property has a value for all boxes. For terminal boxes in the structure
1.34 cvs 5299: and for presentation boxes, the depth value is used during display and
5300: printing: the boxes with the lowest value overlap those with higher depths.
1.37 cvs 5301: For non-terminal boxes, the depth is not interpreted during display, but it
5302: is used to calculate the depth of terminal boxes by inheritance.</p>
1.30 cvs 5303:
5304: <p>Like most other rules, the depth rule is defined in the <a
1.37 cvs 5305: href="#sectc427">default rules</a> of each presentation schema. Thus, there
1.18 cvs 5306: is always a depth value, even when it is not necessary because there is no
1.37 cvs 5307: overlapping. To avoid useless operations, a zero value can be given to the
1.34 cvs 5308: depth property, which signifies that overlapping is never a problem.</p>
1.30 cvs 5309:
5310: <p>The depth rule has the same form as the <a href="#sectc4224">visibility
1.18 cvs 5311: rule</a>. It can be defined by inheritance or by a constant numeric value.
5312: When the rule is attached to a numeric attribute, it can take the value of
5313: that attribute.</p>
5314: <pre> 'Depth' ':' NumberInherit</pre>
1.30 cvs 5315:
1.18 cvs 5316: <blockquote class="example">
1.30 cvs 5317: <p><strong>Example:</strong></p>
5318:
5319: <p>For a purely textual document, in which overlapping never poses a
5320: problem, a single default <tt>Depth</tt> rule in the presentation schema is
5321: sufficient:</p>
5322: <pre>DEFAULT
1.1 cvs 5323: Depth : 0;
1.18 cvs 5324: ...</pre>
1.30 cvs 5325:
5326: <p>To make the text of examples appear on a light blue background, a
5327: presentation box is defined:</p>
5328: <pre>BOXES
1.1 cvs 5329: BlueBG :
5330: BEGIN
5331: Content : Graphics 'R';
5332: Background : LightBlue3;
5333: FillPattern: backgroundcolor;
5334: Depth : 2;
5335: ...
1.18 cvs 5336: END;</pre>
1.30 cvs 5337:
5338: <p>and is created by the <tt>Example</tt> element, which has the rules:</p>
5339: <pre>RULES
1.1 cvs 5340: Example :
5341: BEGIN
5342: CreateFirst (BlueBG);
5343: Depth : 1;
5344: ...
1.18 cvs 5345: END;</pre>
1.30 cvs 5346:
5347: <p>In this way, the text of an example (if it inherits its depth from its
5348: ancestor) will be superimposed on a light blue background, and not the
5349: reverse).</p>
1.18 cvs 5350: </blockquote>
5351: </div>
5352:
5353: <div class="subsection">
1.37 cvs 5354: <h3><a name="sectc4227" id="sectc4227">Line style</a></h3>
1.18 cvs 5355:
1.30 cvs 5356: <p>The <tt>LineStyle</tt> rule determines the style of line which should be
5357: used to draw all the elements contained in the box and the box itself, if it
1.37 cvs 5358: has a <a href="#sectc4230a"><tt>ShowBox</tt> rule</a>. The line style can be
1.18 cvs 5359: indicated by a name (<tt>Solid</tt>, <tt>Dashed</tt>, <tt>Dotted</tt>) or it
1.37 cvs 5360: can be inherited. All elements of the graphic base type are affected by this
1.1 cvs 5361: rule, but it can be attached to any box and transmitted by inheritance to the
1.37 cvs 5362: graphic elements. The border of elements having a <a
1.18 cvs 5363: href="#sectc4230a"><tt>ShowBox</tt> rule</a> is drawn according to the line
5364: style specified by this rule.</p>
1.30 cvs 5365:
1.37 cvs 5366: <p>Only identical inheritance is allowed: the box takes the same line style
5367: as the box from which it inherits. This is indicated by an equals sign after
5368: the kinship specification.</p>
1.18 cvs 5369: <pre> 'LineStyle' ':' LineStyleInherit
1.1 cvs 5370: LineStyleInherit = Kinship '=' /
1.18 cvs 5371: 'Solid' / 'Dashed' / 'Dotted' .</pre>
1.30 cvs 5372:
1.18 cvs 5373: <blockquote class="example">
1.30 cvs 5374: <p><strong>Example:</strong></p>
5375:
1.37 cvs 5376: <p>To specify that, in Figures, the graphical parts should be drawn in
5377: solid lines, the Figure element is given a rule using the <tt>Solid</tt>
5378: name:</p>
1.30 cvs 5379: <pre>Figure :
1.18 cvs 5380: LineStyle : Solid;</pre>
1.30 cvs 5381:
5382: <p>and the elements composing figures are given an inheritance rule:</p>
5383: <pre> LineStyle : Enclosing =;</pre>
1.18 cvs 5384: </blockquote>
5385: </div>
5386:
5387: <div class="subsection">
1.37 cvs 5388: <h3><a name="sectc4228" id="sectc4228">Line thickness</a></h3>
1.18 cvs 5389:
1.37 cvs 5390: <p>The <tt>LineWeight</tt> rule determines the thickness of the lines of all
1.1 cvs 5391: graphical elements which appear in the box, no matter what their line style.
1.37 cvs 5392: Line thickness can be specified by a constant value or by inheritance. A
5393: constant value is a positive number followed by an optional unit
5394: specification (which is absent when using relative units). All available <a
5395: href="#sectc4217">distance units</a> can be used. Line thickness is expressed
1.18 cvs 5396: in the same way as <a href="#sectd42221">line spacing</a>.</p>
5397: <pre> 'LineWeight' ':' DistOrInherit</pre>
1.30 cvs 5398:
1.37 cvs 5399: <p>All elements of the graphic base type are affected by this rule, but it
5400: can be attached to any box and transmitted by inheritance to the graphic
5401: elements. The border of element having a <a
5402: href="#sectc4230a"><tt>ShowBox</tt> rule</a> is also drawn according to the
5403: thickness specified by this rule.</p>
1.30 cvs 5404:
1.18 cvs 5405: <blockquote class="example">
1.30 cvs 5406: <p><strong>Example:</strong></p>
5407:
5408: <p>To specify that, in Figures, the graphical parts should be drawn with
5409: lines 0.3 pt thick, the Figure element is given this rule:</p>
5410: <pre>Figure :
1.18 cvs 5411: LineWeight : 0.3 pt;</pre>
1.30 cvs 5412:
5413: <p>and the elements composing figures are given an inheritance rule:</p>
5414: <pre> LineWeight : Enclosing =;</pre>
1.18 cvs 5415: </blockquote>
5416: </div>
5417:
5418: <div class="subsection">
1.37 cvs 5419: <h3><a name="sectc4229" id="sectc4229">Fill pattern</a></h3>
1.18 cvs 5420:
1.30 cvs 5421: <p>The <tt>FillPattern</tt> rule determines the pattern used to fill closed
1.37 cvs 5422: graphical elements (circles, rectangles, etc.) which appear in the box. This
1.18 cvs 5423: rule also specifies the pattern used to fill the box associated with elements
1.37 cvs 5424: having a <a href="#sectc4230a"><tt>ShowBox</tt> rule</a><a>. This pattern can
5425: be indicated by a named constant or by inheritance. The named constant
5426: identifies one of the patterns available in Thot. The names of the available
1.18 cvs 5427: patterns are: nopattern, foregroundcolor, backgroundcolor, gray1, gray2,
5428: gray3, gray4, gray5, gray6, gray7, horiz1, horiz2, horiz3, vert1, vert2,
1.37 cvs 5429: vert3, left1, left2, left3, right1, right2, right3, square1, square2,
5430: square3, lozenge, brick, tile, sea, basket.</a></p>
1.30 cvs 5431:
5432: <p>Like the other rules peculiar to graphics, <tt>LineStyle</tt> and
1.18 cvs 5433: <tt>LineWeight</tt>, only elements of the graphic base type are affected by
5434: the <tt>FillPattern</tt> rule, but the rule can be attached to any box and
1.37 cvs 5435: transmitted by inheritance to the graphic elements. As with the other rules
1.18 cvs 5436: specific to graphics, only identical inheritance is allowed.</p>
1.30 cvs 5437:
5438: <p>The <tt>FillPattern</tt> rule can also be used to determine whether or not
1.37 cvs 5439: text characters, symbols and pictures should be colored. For these element
1.12 cvs 5440: types (text, symbols, and pictures), the only valid values are
1.18 cvs 5441: <tt>nopattern</tt>, <tt>foregroundcolor</tt>, and <tt>backgroundcolor</tt>.
5442: When <tt>FillPattern</tt> has the value <tt>backgroundcolor</tt>, text
5443: characters, symbols, and bitmaps are given the color specified by the <a
5444: href="#sectc4230"><tt>Background</tt> rule</a> which applies to these
1.37 cvs 5445: elements. When <tt>FillPattern</tt> has the value <tt>foregroundcolor</tt>,
1.18 cvs 5446: these same elements are given the color specified by the <a
5447: href="#sectc4230"><tt>Foreground</tt> rule</a> which applies to these
1.37 cvs 5448: elements. In all other case, text characters are not colored.</p>
1.18 cvs 5449: <pre> 'FillPattern' ':' NameInherit</pre>
1.30 cvs 5450:
1.18 cvs 5451: <blockquote class="example">
1.30 cvs 5452: <p><strong>Example:</strong></p>
5453:
5454: <p>To specify that, in Figures, the closed graphical elements should be
5455: filled with a pattern resembling a brick wall, the Figure element is given
5456: this rule:</p>
5457: <pre>Figure :
1.18 cvs 5458: FillPattern : brick;</pre>
1.30 cvs 5459:
5460: <p>and the elements composing figures are given an inheritance rule:</p>
5461: <pre> FillPattern : Enclosing =;</pre>
1.18 cvs 5462: </blockquote>
5463: </div>
5464:
5465: <div class="subsection">
1.37 cvs 5466: <h3><a name="sectc4230" id="sectc4230">Colors</a></h3>
1.18 cvs 5467:
1.30 cvs 5468: <p>The <tt>Foreground</tt> and <tt>Background</tt> rules determine the
1.37 cvs 5469: foreground and background colors of the base elements which appear in the
5470: box. They also control the color of boxes associated with elements having a
5471: <a href="#sectc4230a"><tt>ShowBox</tt> rule</a>. These colors can be
5472: specified with a named constant or by inheritance. The named constants
5473: specify one of the available colors in Thot. The available color names can be
5474: found in the file <tt>thot.color</tt>. In addition to those names, you can
5475: use the keyword <code>Transparent</code>, to not draw anything.</p>
5476:
5477: <p>The color rules affect the same way all base elements and elements having
5478: a <a href="#sectc4230a"><tt>ShowBox</tt> rule</a>, no matter what their type
5479: (text, graphics, pictures, symbols). The color rules can be associated with
1.30 cvs 5480: any box and can be transmitted by inheritance to the base elements or the
1.37 cvs 5481: elements having a <a href="#sectc4230a"><tt>ShowBox</tt> rule</a>. Like the
1.30 cvs 5482: preceding rules, only inheritance of the same value is allowed.</p>
5483: <pre> 'Foreground' ':' Color
5484: 'Background' ':' Color
5485: Color = 'Transparent' / Link '=' / FontColorName .</pre>
5486:
5487: <p><strong>Note:</strong> text colors only appear for text elements whose <a
1.18 cvs 5488: href="#sectc4229">fill pattern</a> does not prevent the use of color.</p>
1.30 cvs 5489:
1.18 cvs 5490: <blockquote class="example">
1.30 cvs 5491: <p><strong>Example:</strong></p>
5492:
5493: <p>To specify that, in Figures, everything must be drawn in blue on a
5494: background of yellow, the Figure element is given these rules:</p>
5495: <pre>Figure :
1.1 cvs 5496: BEGIN
5497: Foreground : Blue;
5498: Background : Yellow;
5499: Fillpattern : backgroundcolor;
1.18 cvs 5500: END;</pre>
1.30 cvs 5501:
5502: <p>and the elements composing figures are given inheritance rules:</p>
5503: <pre> Foreground : Enclosing =;
1.1 cvs 5504: Background : Enclosing =;
1.18 cvs 5505: FillPattern : Enclosing =;</pre>
5506: </blockquote>
5507: </div>
5508:
5509: <div class="subsection">
1.37 cvs 5510: <h3><a name="sectc4230a" id="sectc4230a">Background color and border</a></h3>
1.18 cvs 5511:
1.30 cvs 5512: <p>Boxes associated with structural elements are normally not visible, but it
1.37 cvs 5513: is possible to draw their border and/or to paint their area when it is
5514: needed. This is achieved by associating the <tt>ShowBox</tt> rule with the
5515: concerned element. This rule has no parameter and no value. It is simply
5516: written <tt>Showbox;</tt>. It is not inherited nor transmitted to any other
5517: element. It applies only to the element with which it is associated.</p>
1.18 cvs 5518: <pre> 'ShowBox'</pre>
1.30 cvs 5519:
5520: <p>When an element has a <tt>ShowBox</tt> rule, the border is drawn only if
1.37 cvs 5521: the <tt>LineWeight</tt> rule that applies to that element has a non-zero
5522: value (this value can be inherited). The color, style and thickness of the
5523: border are defined by the <tt>Foreground</tt>, <tt>LineStyle</tt>, and
1.18 cvs 5524: <tt>LineWeight</tt> rules that apply to the element.</p>
1.30 cvs 5525:
1.37 cvs 5526: <p>When an element has a <tt>ShowBox</tt> rule, the background of this
5527: element is paint only if the value of the <tt>FillPattern</tt> rule that
5528: applies to that element is not <tt>nopattern</tt>. The pattern and color(s)
5529: of the background are defined by the <tt>FillPattern</tt>,
5530: <tt>Background</tt>, and <tt>Foreground</tt> rules that apply to the
5531: element.</p>
1.18 cvs 5532: </div>
5533:
5534: <div class="subsection">
1.37 cvs 5535: <h3><a name="sectc4230b" id="sectc4230b">Background pictures</a></h3>
1.18 cvs 5536:
1.30 cvs 5537: <p>The <tt>BackgroundPicture</tt> rule allows to display a picture as the
1.37 cvs 5538: background of an element. It has a single parameter, the file name of the
5539: picture. This is a string delimited by single quotes. If the first character
1.18 cvs 5540: in this string is '/', it is considered as an absolute path, otherwise the
1.37 cvs 5541: file is searched for along the schema directory path. This file may contain a
1.18 cvs 5542: picture in any format accepted by Thot (xbm, xpm, gif, jpeg, png, etc.)</p>
1.30 cvs 5543:
1.37 cvs 5544: <p>The <tt>BackgroundPicture</tt> and <tt>PictureMode</tt> rules apply only
5545: to the element with which they are associated. They are not inherited nor
1.18 cvs 5546: transmitted to children elements.</p>
1.30 cvs 5547:
5548: <p>The background picture has not always the same size as the element's box.
1.37 cvs 5549: There are diffrent ways to fill the element box with the picture. This is
1.18 cvs 5550: specified by the <tt>PictureMode</tt> rule, which should be associated to the
1.37 cvs 5551: same element. This rule may take one of the following values:</p>
1.18 cvs 5552: <dl>
1.30 cvs 5553: <dt><tt>NormalSize</tt></dt>
5554: <dd>The picture is centered in the box, and clipped if it is too
5555: large.</dd>
5556: <dt><tt>Scale</tt></dt>
5557: <dd>The picture is zoomed to fit the box size.</dd>
5558: <dt><tt>RepeatX</tt></dt>
5559: <dd>The picture is repeated horizontally to fit the box width.</dd>
5560: <dt><tt>RepeatY</tt></dt>
5561: <dd>The picture is repeated vertically to fit the box height.</dd>
5562: <dt><tt>RepeatXY</tt></dt>
5563: <dd>The picture is repeated both horizontally and vertically to fill the
5564: box.</dd>
1.18 cvs 5565: </dl>
1.30 cvs 5566:
5567: <p>If an element has a <tt>BackgroundPicture</tt> rule and no
1.18 cvs 5568: <tt>PictureMode</tt> rule, the <tt>NormalSize</tt> value is assumed.</p>
5569: <pre> 'BackgroundPicture' ':' FileName /
1.13 cvs 5570: 'PictureMode' ':' PictMode .
5571:
5572: FileName = STRING .
1.18 cvs 5573: PictMode = 'NormalSize' / 'Scale' / 'RepeatXY' / 'RepeatX' / 'RepeatY' .</pre>
1.30 cvs 5574:
1.37 cvs 5575: <p>The <tt>BackgroundPicture</tt> and <tt>PictureMode</tt> rules apply only
5576: to the element with which they are associated. They are not inherited nor
1.18 cvs 5577: transmitted to children elements.</p>
5578: </div>
1.13 cvs 5579:
1.18 cvs 5580: <div class="subsection">
1.47 quint 5581: <h3><a name="sectc4230c" id="sectc4230c">Opacity</a></h3>
5582:
1.48 quint 5583: <p>The <tt>Opacity</tt>, <tt>FillOpacity</tt> and <tt>StrokeOpacity</tt>
5584: rules allow to set the opacity of the element(s) to which they apply. The
5585: <code>FillOpacity</code> rule controls the way the interior of the element is
5586: paint, while the <code>StrokeOpacity</code> rule concerns the outline. The
5587: <code>Opacity</code> rule concerns both the interior and the outline at the
5588: same time.</p>
5589:
5590: <p>In the three rules, opacity is expressed as a percentage. It must be
5591: comprised between 0 (fully transparent) and 100% (fully opaque). In these
5592: rules, the opacity can be expressed as an integer (from 0 to 100) followed by
5593: the <code>%</code> character. It can also be expressed as the name of a
5594: numeric attribute. In that case, the attribute's value is interpreted as a
5595: percentage. It should then be comprised between 0 and 100 included. Finally,
5596: the opacity can be inherited from the parent element.</p>
5597: <pre> 'Opacity' ':' OpacityInherit
5598: 'FillOpacity' ':' OpacityInherit
5599: 'StrokeOpacity' ':' OpacityInherit
1.47 quint 5600: OpacityInherit = OpPercent '%' / AttrID / Inheritance .
5601: OpPercent = NUMBER .</pre>
5602: </div>
5603:
5604: <div class="subsection">
1.37 cvs 5605: <h3><a name="sectc4231" id="sectc4231">Presentation box content</a></h3>
1.1 cvs 5606:
1.37 cvs 5607: <p>The <tt>Content</tt> rule applies to presentation boxes. It indicates the
5608: content given to a box. This content is either a variable's value or a
5609: constant value.</p>
1.30 cvs 5610:
5611: <p>If the content is a constant, it can be specified, as in a variable
1.18 cvs 5612: declaration, either by the name of a constant declared in the <tt>CONST</tt>
1.1 cvs 5613: section or by direct specification of the type and value of the box's
1.18 cvs 5614: content.</p>
1.30 cvs 5615:
5616: <p>Similarly, if it is a variable, the name of a variable declared in
1.18 cvs 5617: <tt>VAR</tt> section can be given or the variable may be defined within
1.37 cvs 5618: parentheses. The content inside the parentheses has the same syntax as a <a
1.18 cvs 5619: href="#sectc426">variable declaration</a>.</p>
5620: <pre> 'Content' ':' VarConst
1.1 cvs 5621: VarConst = ConstID / ConstType ConstValue /
1.38 cvs 5622: VarID / '(' FunctionSeq ')' .</pre>
1.30 cvs 5623:
5624: <p>A presentation box can have only one <tt>Content</tt> rule, which means
1.37 cvs 5625: that the content of a presentation box cannot vary from view to view.
5626: However, such an effect can be achieved by creating several presentation
5627: boxes, each with different content and visible in different views.</p>
5628:
5629: <p>The <tt>Content</tt> rule also applies to elements defined as references
5630: in the structure schema. In this case, the content defined by the rule must
5631: be a constant. It is this content which appears on the screen or paper to
5632: represent references of the type to which the rule applies. A reference can
1.18 cvs 5633: have a <tt>Content</tt> rule or a <a href="#sectc4234"><tt>Copy</tt> rule</a>
1.37 cvs 5634: for each view. If neither of these rules appears, the reference is displayed
1.18 cvs 5635: as <tt>[*]</tt>, which is equivalent to the rule:</p>
5636: <pre> Content: Text '[*]';</pre>
1.30 cvs 5637:
1.18 cvs 5638: <blockquote class="example">
1.30 cvs 5639: <p><strong>Example:</strong></p>
5640:
5641: <p>The content of the presentation box created to make the chapter number
5642: and section number appear before each section title can be defined by:</p>
5643: <pre>BOXES
1.1 cvs 5644: SectionNumBox :
5645: BEGIN
5646: Content : NumSection;
5647: ...
1.18 cvs 5648: END;</pre>
1.30 cvs 5649:
5650: <p>if the <tt>NumSection</tt> variable has been defined in the variable
1.37 cvs 5651: definition section of the presentation schema. Otherwise the
1.30 cvs 5652: <tt>Content</tt> would be written:</p>
5653: <pre>BOXES
1.1 cvs 5654: SectionNumBox :
5655: BEGIN
5656: Content : (VALUE (ChapterCtr, Roman) TEXT '.'
5657: VALUE (SectionCtr, Arabic));
5658: ...
1.18 cvs 5659: END;</pre>
5660: </blockquote>
5661: </div>
1.1 cvs 5662:
1.18 cvs 5663: <div class="subsection">
1.37 cvs 5664: <h3><a name="sectc4232" id="sectc4232">Presentation box creation</a></h3>
1.1 cvs 5665:
1.37 cvs 5666: <p>A creation rule specifies that a presentation box should be created when
5667: an element of the type to which the rule is attached appears in the
5668: document.</p>
1.30 cvs 5669:
5670: <p>A keyword specifies the position, relative to the creating box, at which
5671: the created box will be placed in the structure:</p>
1.18 cvs 5672: <dl>
1.30 cvs 5673: <dt><tt>CreateFirst</tt></dt>
5674: <dd>specifies that the box should be created as the first box of the next
5675: lower level, before any already existing boxes, and only if the
5676: beginning of the creating element is visible;</dd>
5677: <dt><tt>CreateLast</tt></dt>
5678: <dd>specifies that the box should be created as the last box of the next
5679: lower level, after any existing boxes, and only if the end of the
5680: creating element is visible;</dd>
5681: <dt><tt>CreateBefore</tt></dt>
5682: <dd>specifies that the box should be created before the creating box, on
5683: the same level as the creating box, and only if the beginning of the
5684: creating element is visible;</dd>
5685: <dt><tt>CreateAfter</tt></dt>
5686: <dd>specifies that the box should be created after the creating box, on
5687: the same level as the creating box, and only if the beginning of the
5688: creating element is visible;</dd>
5689: <dt><tt>CreateEnclosing</tt></dt>
1.37 cvs 5690: <dd>specifies that the box should be created at the upper level
5691: relatively to the creating box, and that it must contain that creating
5692: box and all presentation boxes created by the same creating box.</dd>
1.18 cvs 5693: </dl>
1.30 cvs 5694:
5695: <p>This keyword can be followed by the <tt>Repeated</tt> keyword to indicate
5696: that the box must be created for each part of the creating element. These
5697: parts result from the division of the element by page breaks or column
1.37 cvs 5698: changes. If the <tt>Repeated</tt> keyword is missing, the box is only created
1.30 cvs 5699: for the first part of the creating element (<tt>CreateFirst</tt> and
1.18 cvs 5700: <tt>CreateBefore</tt> rules) or for the last part (<tt>CreateLast</tt> and
5701: <tt>CreateAfter</tt> rules).</p>
1.30 cvs 5702:
5703: <p>The type of presentation to be created is specified at the end of the rule
1.18 cvs 5704: between parentheses.</p>
1.30 cvs 5705:
5706: <p>Creation rules cannot appear in the <a href="#sectc427">default
1.37 cvs 5707: presentation rules</a>. The boxes being created should have a
1.30 cvs 5708: <tt>Content</tt> rule which indicates their <a
5709: href="#sectc4231">content</a>.</p>
5710:
5711: <p>Creation rules can only appear in the block of rules for the primary view;
1.1 cvs 5712: creation is provoked by a document element for all views. However, for each
1.37 cvs 5713: view, the presentation box is only created if the creating element is itself
5714: a box in the view. Moreover, the visibility property of the presentation box
5715: can be adjusted to control the creation of the box on a view-by-view
5716: basis.</p>
1.18 cvs 5717: <pre> Creation '(' BoxID ')'
1.1 cvs 5718: Creation = Create [ 'Repeated' ] .
5719: Create ='CreateFirst' / 'CreateLast' /
5720: 'CreateBefore' / 'CreateAfter' /
1.18 cvs 5721: 'CreateEnclosing' .</pre>
1.30 cvs 5722:
1.18 cvs 5723: <blockquote class="example">
1.30 cvs 5724: <p><strong>Example:</strong></p>
5725:
5726: <p>Let us define an object type, called Table, which is composed of a
5727: sequence of columns, all having the same fixed width, where the columns are
1.37 cvs 5728: separated by vertical lines. There is a line to the left of the first
5729: column and one to the right of the last. Each column has a variable number
1.31 cvs 5730: of cells, placed one on top of the other and separated by horizontal lines.
5731: There are no horizontal lines above the first cell or below the last cell.
1.37 cvs 5732: The text contained in each cell is broken into lines and these lines are
1.30 cvs 5733: centered horizontally in the cell. The logical structure of this object is
5734: defined by:</p>
5735: <pre>Table = LIST OF (Column);
1.18 cvs 5736: Column = LIST OF (Cell = Text);</pre>
5737:
1.30 cvs 5738: <div class="figure">
1.37 cvs 5739: <hr />
1.30 cvs 5740: <pre>| | | |
1.1 cvs 5741: | xx xxxx xxxx |x xxxx xxx xxxxx| x xxx x xxx |
5742: | xxx xxx xxxx x | x xx x xxx | xxxxx xxxx xx |
5743: | xxxxx xxxx |----------------| xxx xxxxx x |
5744: | xxxxx xxx xxxx | xxxx xx xx xxx | xx xx |
5745: | xxx xxxx x xxx | xxxx x xxx x |---------------|
5746: |----------------| xxx xxxx xxxxx | xxxxx xxxxx |
5747: | xxx xxx xxxxxx |----------------| xxx xxxx xxxx |
5748: | xxxx xxxx xx | xxxx xx x xx | xxx xx x xx |
5749: |----------------| xxx xxxxx xxxx | xxxx xxxx xxx |
5750: | xxxxx xxx xxxx | xxxx xx x xx | xxxxx xxx |
1.18 cvs 5751: |xxxx xx x xxxxxx| xxxx xx xxxxxx | xxxxx xxxxx |</pre>
1.19 cvs 5752:
1.37 cvs 5753: <p align="center"><em><a name="table" id="table">The design of a
5754: table</a></em></p>
5755: <hr />
1.30 cvs 5756: </div>
5757:
5758: <p>The presentation of the table should resemble the design of the above <a
1.37 cvs 5759: href="#table">figure</a>. It is defined by the following presentation
1.30 cvs 5760: schema fragment:</p>
5761: <pre>BOXES
1.1 cvs 5762: VertLine : BEGIN
5763: Width : 0.3 cm;
5764: Height : Enclosing . Height;
5765: VertPos : Top = Enclosing . Top;
5766: HorizPos : Left = Previous . Right;
5767: Content : Graphics 'v';
5768: END;
5769:
5770: HorizLine: BEGIN
5771: Width : Enclosing . Width;
5772: Height : 0.3 cm;
5773: VertPos : Top = Previous . Bottom;
5774: HorizPos : Left = Enclosing . Left;
5775: Content : Graphics 'h';
5776: END;
5777:
5778: RULES
1.6 cvs 5779: Column : BEGIN
5780: CreateBefore (VertLine);
5781: IF LAST CreateAfter (VertLine);
5782: Width : 2.8 cm;
5783: Height : Enclosed . Height;
5784: VertPos : Top = Enclosing . Top;
5785: HorizPos : Left = Previous . Right;
5786: END;
5787:
5788: Cell : BEGIN
5789: IF NOT FIRST CreateBefore (HorizLine);
5790: Width : Enclosing . Width;
5791: Height : Enclosed . Height;
5792: VertPos : Top = Previous . Bottom;
5793: HorizPos : Left = Enclosing . Left;
5794: Line;
5795: Adjust : VMiddle;
1.18 cvs 5796: END;</pre>
1.30 cvs 5797:
5798: <p>It is useful to note that the horizontal position rule of the first
5799: vertical line will not be applied, since there is no preceding box. In this
5800: case, the box is simply placed on the left side of the enclosing box.</p>
1.18 cvs 5801: </blockquote>
5802: </div>
5803:
5804: <div class="subsection">
1.37 cvs 5805: <h3><a name="sectc4233" id="sectc4233">Page layout</a></h3>
1.18 cvs 5806:
1.30 cvs 5807: <p>The page models specified in the <tt>Page</tt> rule are defined by boxes
1.37 cvs 5808: declared in the <tt>BOXES</tt> section of the presentation schema. Pages are
1.1 cvs 5809: not described as frames which will be filled by the document's text, but as
5810: element are inserted in the flow of the document and which mark the page
1.37 cvs 5811: breaks. Each of these page break elements contains presentation boxes which
1.1 cvs 5812: represent the footer boxes of a page followed by header boxes of the next
1.37 cvs 5813: page. The page box itself is the simple line which separates two pages on the
5814: screen. Both the footer and header boxes placed themselves with respect to
1.1 cvs 5815: this page box, with the footer being placed above it and the header boxes
1.18 cvs 5816: being placed above it.</p>
1.30 cvs 5817:
5818: <p>The boxes created by a page box are headers and footers and can only place
1.1 cvs 5819: themselves vertically with respect to the page box itself (which is in fact
1.37 cvs 5820: the separation between two pages). Besides, it is their vertical position
5821: rule which determines whether they are header or footer boxes. Header and
1.1 cvs 5822: footer boxes must have an explicit vertical position rule (they must not use
1.18 cvs 5823: the default rule).</p>
1.30 cvs 5824:
5825: <p>Footer boxes must have an absolute height or inherit the height of their
1.18 cvs 5826: contents:</p>
5827: <pre>Height : Enclosed . Height;</pre>
1.30 cvs 5828:
5829: <p>A page box must have height and width rules and these two rules must be
1.1 cvs 5830: specified with constant values, expressed in centimeters, inches, or
1.37 cvs 5831: typographer's points. These two rules are interpreted in a special way for
5832: page boxes: they determine the width of the page and the vertical distance
1.1 cvs 5833: between two page separators, which is the height of the page and its header
1.18 cvs 5834: and footer together.</p>
1.30 cvs 5835:
5836: <p>A page box should also have vertical and horizontal position rules and
5837: these two rules should specify the position on the sheet of paper of the
1.37 cvs 5838: rectangle enclosing the page's contents. These two rules must position the
1.30 cvs 5839: upper left corner of the enclosing rectangle in relation to the upper left
1.37 cvs 5840: corner of the sheet of paper, considered to be the enclosing element. In both
1.30 cvs 5841: rules, distances must be expressed in fixed units: centimeters (<tt>cm</tt>),
1.37 cvs 5842: inches (<tt>in</tt>), or typographer's points (<tt>pt</tt>). Thus, rules
1.30 cvs 5843: similar to the following should be found in the rules for a page box:</p>
1.18 cvs 5844: <pre>BOXES
1.1 cvs 5845: ThePage :
5846: BEGIN
5847: VertPos : Top = Enclosing . Top + 3 cm;
5848: HorizPos : Left = Enclosing . Left + 2.5 cm;
5849: Width : 16 cm;
5850: Height : 22.5 cm;
1.18 cvs 5851: END;</pre>
1.30 cvs 5852:
5853: <p>When a document must be page broken, the page models to be constructed are
1.18 cvs 5854: defined in the <tt>BOXES</tt> section of the presentation schema by declaring
1.37 cvs 5855: page boxes and header and footer boxes. Also, the <tt>Page</tt> rule is used
5856: to specify to which parts of the document and to which views each model
5857: should be applied.</p>
1.30 cvs 5858:
5859: <p>The <tt>Page</tt> rule has only one parameter, given between parentheses
1.37 cvs 5860: after the <tt>Page</tt> keyword. This parameter is the name of the box which
5861: must serve as the model for page construction. When a <tt>Page</tt> rule is
1.1 cvs 5862: attached to an element type, each time such an element appears in a document,
5863: a page break takes place and the page model indicated in the rule is applied
5864: to all following pages, until reaching the next element which has a
1.18 cvs 5865: <tt>Page</tt> rule.</p>
1.30 cvs 5866:
5867: <p>The <tt>Page</tt> rule applies to only one view; if it appears in the
1.37 cvs 5868: primary view's block of rules, a <tt>Page</tt> rule applies only to that
5869: view. Thus, different page models can be defined for the full document and
5870: for its table of contents, which is another view of the same document. Some
5871: views can be specified with pages, and other views of the same document can
5872: be specified without pages.</p>
1.18 cvs 5873: <pre> 'Page' '(' BoxID ')'</pre>
5874: </div>
5875:
5876: <div class="subsection">
1.37 cvs 5877: <h3><a name="sectc4234" id="sectc4234">Box copies</a></h3>
1.18 cvs 5878:
1.30 cvs 5879: <p>The <tt>Copy</tt> rule can be used for an element which is defined as a
1.37 cvs 5880: reference in the structure schema. In this case, the rule specifies, between
1.18 cvs 5881: parenthesis, the name of the box (declared in the <tt>BOXES</tt> section)
1.1 cvs 5882: which must be produced when this reference appears in the structure of a
1.37 cvs 5883: document. The box produced is a copy (same contents, but possible different
1.1 cvs 5884: presentation) of the box type indicated by the parameter between parentheses,
1.37 cvs 5885: and which is in the element designated by the reference. The name of a box
1.1 cvs 5886: can be replaced by type name. Then what is copied is the contents of the
1.18 cvs 5887: element of this type which is inside the referenced element.</p>
1.30 cvs 5888:
1.37 cvs 5889: <p>Whether a box name or type name is given, it may be followed by the name
5890: of a structure schema between parentheses. This signifies that the box or
5891: type is defined in the indicated structure schema and not in the structure
5892: schema with which the rule's presentation schema is associated.</p>
1.30 cvs 5893:
1.37 cvs 5894: <p>The <tt>Copy</tt> rule can also be applied to a presentation box. If the
1.1 cvs 5895: presentation box was created by a reference attribute, the rule is applied as
5896: in the case of a reference element: the contents of the box having the
1.18 cvs 5897: <tt>Copy</tt> rule are based on the element designated by the reference
1.37 cvs 5898: attribute. For other presentation boxes, the <tt>Copy</tt> rule takes a type
1.1 cvs 5899: name parameter which can be followed, between parentheses, by the name of the
5900: structure schema in which the type is defined, if it is not defined in the
1.37 cvs 5901: same schema. The contents of the box which has this rule are a copy of the
5902: element of this type which is in the element creating the presentation box,
5903: or by default, the box of this type which precedes the presentation box. This
5904: last facility is used, for example, to define the running titles in headers
5905: or footers.</p>
1.18 cvs 5906: <pre> 'Copy' '(' BoxTypeToCopy ')' .
1.1 cvs 5907: BoxTypeToCopy = BoxID [ ExtStruct ] /
1.6 cvs 5908: ElemID [ ExtStruct ] .
1.18 cvs 5909: ExtStruct = '(' ElemID ')' .</pre>
1.30 cvs 5910:
5911: <p>Like the creation rules, the <tt>Copy</tt> rule cannot appear in the <a
1.37 cvs 5912: href="#sectc427">default presentation rules</a>. Moreover, this rule can only
1.18 cvs 5913: appear in the primary view's block of rules; the copy rule is applied to all
5914: views.</p>
1.30 cvs 5915:
1.18 cvs 5916: <blockquote class="example">
1.30 cvs 5917: <p><strong>Example:</strong></p>
5918:
5919: <p>If the following definitions are in the structure schema:</p>
5920: <pre>Body = LIST OF (Chapter =
1.1 cvs 5921: BEGIN
5922: ChapterTitle = Text;
5923: ChapterBody = SectionSeq;
5924: END);
1.18 cvs 5925: RefChapter = REFERENCE (Chapter);</pre>
1.30 cvs 5926:
5927: <p>then the following presentation rules (among many other rules in the
5928: presentation schema) can be specified:</p>
5929: <pre>COUNTERS
1.1 cvs 5930: ChapterCtr : RANK OF Chapter;
5931: BOXES
5932: ChapterNumber :
5933: BEGIN
5934: Content : (VALUE (ChapterCtr, URoman));
5935: ...
5936: END;
5937: RULES
5938: Chapter :
5939: BEGIN
5940: CreateFirst (ChapterNumber);
5941: ...
5942: END;
5943: RefChapter :
5944: BEGIN
5945: Copy (ChapterNumber);
5946: ...
1.18 cvs 5947: END;</pre>
1.30 cvs 5948:
5949: <p>which makes the number of the chapter designated by the reference appear
5950: in uppercase roman numerals, in place of the reference to a chapter itself.
5951: Alternatively, the chapter title can be made to appear in place of the
5952: reference by writing this <tt>Copy</tt>rule:</p>
5953: <pre> Copy (ChapterTitle);</pre>
5954:
5955: <p>To define a header box, named <tt>RunningTitle</tt>, which contains the
5956: title of the current chapter, the box's contents are defined in this
5957: way:</p>
5958: <pre>BOXES
1.1 cvs 5959: RunningTitle :
1.18 cvs 5960: Copy (ChapterTitle);</pre>
5961: </blockquote>
5962: </div>
5963: </div>
1.37 cvs 5964: <hr />
1.18 cvs 5965: </div>
1.1 cvs 5966:
1.18 cvs 5967: <div class="chapter">
1.37 cvs 5968: <h1><a name="sect5" id="sect5">The T language</a></h1>
1.1 cvs 5969:
1.18 cvs 5970: <div class="section">
1.37 cvs 5971: <h2><a name="sectb51" id="sectb51">Document translation</a></h2>
1.1 cvs 5972:
1.30 cvs 5973: <p>Because of its document model, Thot can produce documents in a high-level
1.37 cvs 5974: abstract form. This form, called the <em>canonical form</em> is specific to
1.1 cvs 5975: Thot; it is well suited to the editor's manipulations, but it does not
1.37 cvs 5976: necessarily suit other operations which might be applied to documents.
5977: Because of this, the Thot editor offers the choice of saving documents in its
5978: own form (the canonical form) or a format defined by the user. In the latter
5979: case, the Thot document is transformed by the translation program. This
5980: facility can also be used to export documents from Thot to systems using
5981: other formalisms.</p>
1.1 cvs 5982:
1.18 cvs 5983: <div class="subsection">
1.37 cvs 5984: <h3><a name="sectc511" id="sectc511">Translation principles</a></h3>
1.1 cvs 5985:
1.30 cvs 5986: <p>Document translation allows the export of documents to other systems which
1.37 cvs 5987: do not accept Thot's canonical form. Translation can be used to export
1.30 cvs 5988: document to source-based formatters like T<sub><big>E</big></sub>X,
1.37 cvs 5989: L<sup>A</sup>T<sub><big>E</big></sub>X, and <tt>troff</tt>. It can also be
5990: used to translate documents into interchange formats like SGML or HTML. To
1.1 cvs 5991: allow the widest range of possible exports, Thot does not limit the choice of
5992: translations, but rather allows the user to define the formalisms into which
1.18 cvs 5993: documents can be translated.</p>
1.30 cvs 5994:
5995: <p>For each document or object class, a set of translation rules can be
5996: defined, specifying how the canonical form should be transformed into a given
1.37 cvs 5997: formalism. These translation rules are grouped into <em>translation
1.18 cvs 5998: schemas</em>, each schema containing the rules necessary to translate a
1.1 cvs 5999: generic logical structure (document or object structure) into a particular
1.37 cvs 6000: formalism. The same generic logical structure can have several different
1.1 cvs 6001: translation schemas, each defining translation rules for a different
1.18 cvs 6002: formalism.</p>
1.30 cvs 6003:
1.37 cvs 6004: <p>Like presentation schemas, translation schemas are generic. Thus, they
1.30 cvs 6005: apply to an entire object or document class and permit translation of all
6006: documents or objects of that class.</p>
1.18 cvs 6007: </div>
1.1 cvs 6008:
1.18 cvs 6009: <div class="subsection">
1.37 cvs 6010: <h3><a name="sectc512" id="sectc512">Translation procedure</a></h3>
1.1 cvs 6011:
1.30 cvs 6012: <p>The translator works on the specific logical structure of the document
1.37 cvs 6013: being translated. It traverses the primary tree of this logical structure in
1.1 cvs 6014: pre-order and, at each node encountered, it applies the corresponding
6015: translation rules defined in the translation schema. Translation can be
1.18 cvs 6016: associated:</p>
6017: <ul>
1.30 cvs 6018: <li>with element types defined in the structure schema,</li>
6019: <li>with global or local attributes defined in the structure schema,</li>
6020: <li>with specific presentation rules,</li>
1.37 cvs 6021: <li>with the content of the leaves of the structure (characters, symbols
1.30 cvs 6022: and graphical elements)</li>
1.18 cvs 6023: </ul>
1.30 cvs 6024:
6025: <p>Thus, for each node, the translator applies all rules associated with the
1.1 cvs 6026: element type, all rules associated with each attribute (local or global)
6027: carried by the element, and if the element is a leaf of the tree, it also
1.10 cvs 6028: applies translation rules for characters, symbols, or graphical elements,
1.18 cvs 6029: depending on the type of the leaf.</p>
1.30 cvs 6030:
6031: <p>Rules associated with the content of leaves are different from all other
1.1 cvs 6032: rules: they specify only how to translate character strings, symbols, and
1.37 cvs 6033: graphical elements. All other rules, whether associated with element types,
1.1 cvs 6034: with specific presentation rules or with attributes, are treated similarly.
1.18 cvs 6035: These rules primarily allow:</p>
6036: <ul>
1.30 cvs 6037: <li>generation of a text constant or variable before or after the contents
6038: of an element,</li>
6039: <li>modification of the order in which elements appear after
6040: translation,</li>
6041: <li>removal of an element in the translated document,</li>
6042: <li>and writing messages on the user's terminal during translation.</li>
1.18 cvs 6043: </ul>
6044: </div>
6045: </div>
1.1 cvs 6046:
1.18 cvs 6047: <div class="section">
1.37 cvs 6048: <h2><a name="sectb52" id="sectb52">Translation definition language</a></h2>
1.1 cvs 6049:
1.30 cvs 6050: <p>Translation schemas are written in a custom language, called T, which is
1.37 cvs 6051: described in the rest of this chapter. The grammar of T is specified using
1.18 cvs 6052: the same <a href="#sectc321">meta-language</a> as was used for the S and P
1.1 cvs 6053: languages and the translation schemas are written using the same conventions
1.37 cvs 6054: as the structure and presentation schemas. In particular, the keywords of the
1.1 cvs 6055: T language (the stings between apostrophes in the following syntax rules) can
6056: be written in any combination of upper-case and lower-case letters, but
6057: identifiers created by the programmer must always be written in the same
1.18 cvs 6058: way.</p>
1.1 cvs 6059:
1.18 cvs 6060: <div class="subsection">
1.37 cvs 6061: <h3><a name="sectc521" id="sectc521">Organization of a translation
6062: schema</a></h3>
1.1 cvs 6063:
1.30 cvs 6064: <p>A translation schema is begun by the <tt>TRANSLATION</tt> keyword and is
1.37 cvs 6065: terminated by the <tt>END</tt> keyword. The <tt>TRANSLATION</tt> keyword is
6066: followed by the name of the generic structure for which a translation is
6067: being defined and a semicolon. This name must be identical to the name which
1.18 cvs 6068: appears after the <tt>STRUCTURE</tt> keyword in the corresponding structure
6069: schema.</p>
1.30 cvs 6070:
6071: <p>After this declaration of the structure, the following material appears in
1.18 cvs 6072: order:</p>
6073: <ul>
1.30 cvs 6074: <li>the length of lines produced by the translation,</li>
6075: <li>the character delimiting the end of the line,</li>
6076: <li>the character string which the translator will insert if it must
6077: line-break the translated text,</li>
1.37 cvs 6078: <li>declarations of
1.30 cvs 6079: <ul>
6080: <li>buffers,</li>
6081: <li>counters,</li>
6082: <li>constants,</li>
6083: <li>variables,</li>
6084: </ul>
6085: </li>
6086: <li>translation rules associated with element types,</li>
6087: <li>translation rules associated with attributes,</li>
6088: <li>translation rules associated with specific presentation rules,</li>
6089: <li>translation rules associated with characters strings, symbols and
6090: graphical elements.</li>
1.18 cvs 6091: </ul>
1.30 cvs 6092:
1.37 cvs 6093: <p>Each of these sections is introduced by a keyword followed by a sequence
6094: of declarations. All of these sections are optional, expect for the
6095: translation rules associated with element types. Many <tt>TEXTTRANSLATE</tt>
6096: sections can appear, each defining the rules for translating character
1.41 vatton 6097: strings of a particular script.</p>
1.18 cvs 6098: <pre> TransSchema ='TRANSLATION' ElemID ';'
1.1 cvs 6099: [ 'LINELENGTH' LineLength ';' ]
6100: [ 'LINEEND' CHARACTER ';' ]
6101: [ 'LINEENDINSERT' STRING ';' ]
6102: [ 'BUFFERS' BufferSeq ]
6103: [ 'COUNTERS' CounterSeq ]
6104: [ 'CONST' ConstSeq ]
6105: [ 'VAR' VariableSeq ]
6106: 'RULES' ElemSeq
6107: [ 'ATTRIBUTES' AttrSeq ]
6108: [ 'PRESENTATION' PresSeq ]
1.30 cvs 6109: < 'TEXTTRANSLATE' TextTransSeq >
1.1 cvs 6110: [ 'SYMBTRANSLATE' TransSeq ]
6111: [ 'GRAPHTRANSLATE' TransSeq ]
1.18 cvs 6112: 'END' .</pre>
6113: </div>
1.1 cvs 6114:
1.18 cvs 6115: <div class="subsection">
1.37 cvs 6116: <h3><a name="sectc522" id="sectc522">Line length</a></h3>
1.1 cvs 6117:
1.30 cvs 6118: <p>If a <tt>LINELENGTH</tt> instruction is present after the structure
1.37 cvs 6119: declaration, the translator divides the text it produces into lines, each
6120: line having a length less than or equal to the integer which follows the
6121: <tt>LINELENGTH</tt> keyword. This maximum line length is expressed as a
6122: number of characters. The end of the line is marked by the character defined
6123: by the <tt>LINEEND</tt> instruction. When the translator breaks the lines on
1.1 cvs 6124: a space character in generated text, this space will be replaced by the
1.18 cvs 6125: character string defined by the <tt>LINEENDINSERT</tt> instruction.</p>
1.30 cvs 6126:
6127: <p>If the <tt>LINEEND</tt> instruction is not defined then the linefeed
6128: character (octal code 12) is used as the default line end character. If the
1.18 cvs 6129: <tt>LINEENDINSERT</tt> instruction is not defined, the linefeed character is
1.37 cvs 6130: inserted at the end of the produced lines. If there is no <tt>LINELENGTH</tt>
6131: instruction, the translated text is not divided into lines. Otherwise, if the
1.1 cvs 6132: translation rules generate line end marks, these marks remain in the
6133: translated text, but the length of the lines is not controlled by the
1.18 cvs 6134: translator.</p>
6135: <pre> LineLength = NUMBER .</pre>
1.30 cvs 6136:
1.18 cvs 6137: <blockquote class="example">
1.30 cvs 6138: <p><strong>Example:</strong></p>
6139:
6140: <p>To limit the lines produced by the translator to a length of 80
6141: characters, the following rule is written at the beginning of the
6142: translation schema.</p>
6143: <pre>LineLength 80;</pre>
1.18 cvs 6144: </blockquote>
6145: </div>
1.1 cvs 6146:
1.18 cvs 6147: <div class="subsection">
1.37 cvs 6148: <h3><a name="sectc523" id="sectc523">Buffers</a></h3>
1.1 cvs 6149:
1.37 cvs 6150: <p>A buffer is a unit of memory managed by the translator, which can either
1.18 cvs 6151: contain text read from the terminal during the translation (see the <a
6152: href="#sectc5212"><tt>Read</tt> rule</a>), or the name of the last picture
1.46 quint 6153: (bit-map) encountered by the translator in its traversal of the document, or
6154: a character string set by program. Remember the pictures are stored in files
6155: that are separate for the document files and that the canonical form contains
6156: only the names of the files in which the pictures are found.</p>
6157:
6158: <p>Thus, there are three types of buffers: buffers for reading from the
6159: terminal (filled by the <tt>Read</tt> rule), the buffer of picture names
6160: (containing the name of the last picture encountered) and buffer filled by
6161: programs (see function <code>SetVariableBuffer</code> in the code) also
6162: called <em>variable buffers</em>. A translation schema can use all types of
6163: buffers, one or several read buffers, one (and only one) picture name buffer,
6164: and one or several variable buffers.</p>
1.30 cvs 6165:
6166: <p>If any buffers are used, the <tt>BUFFERS</tt> keyword must be present,
1.37 cvs 6167: followed by declarations of every buffer used in the translation schema. Each
1.46 quint 6168: buffer declaration is composed of the name of the buffer, chosen freely by
6169: the programmer, followed by a keyword between parentheses to define the type
6170: of the buffer (read buffers do not require any keyword, as they are the
6171: default type). The picture name buffer is identified by the <tt>Picture</tt>
6172: keyword, between parentheses, following the buffer name. The <tt>Picture</tt>
6173: keyword may only appear once. A variable buffer is identified by the
6174: <tt>Variable</tt> keyword, between parentheses, following the buffer name.
6175: Each buffer declaration is terminated by a semicolon.</p>
6176: <pre> BufferSeq = Buffer < Buffer > .
6177: Buffer = BufferID [ '(' BufferType ')' ] ';' .
6178: BufferID = NAME .
6179: BufferType = 'Picture' / 'Variable' .</pre>
1.30 cvs 6180:
1.18 cvs 6181: <blockquote class="example">
1.30 cvs 6182: <p><strong>Example:</strong></p>
6183:
6184: <p>The following buffer declarations create a picture name buffer named
1.37 cvs 6185: <tt>pictureName</tt> and a read buffer named <a name="destname"
6186: id="destname"><tt>DestName</tt></a>:</p>
1.30 cvs 6187: <pre>BUFFERS
1.18 cvs 6188: pictureName (Picture); DestName;</pre>
6189: </blockquote>
6190: </div>
1.1 cvs 6191:
1.18 cvs 6192: <div class="subsection">
1.37 cvs 6193: <h3><a name="sectc524" id="sectc524">Counters</a></h3>
1.30 cvs 6194:
6195: <p>Certain translation rules generate text that varies according to the
1.37 cvs 6196: context of the element to which the rules apply. Variable text is defined
1.30 cvs 6197: either in the <a href="#sectc526"><tt>VAR</tt> section</a> of the translation
6198: schema or in the rule itself (see the <tt>Create</tt> and <tt>Write</tt>
1.37 cvs 6199: rules). Both types of definition rely on counters for the calculation of
1.30 cvs 6200: variable material.</p>
6201:
6202: <p>There are two types of counter: counters whose value is explicitely
6203: computed by applying <a href="#sectc5221"><tt>Set</tt> and <tt>Add</tt>
6204: rules</a>, and counters whose value is computed by a function associated with
6205: the counter. Those functions allow the same calculations as can be used in
1.37 cvs 6206: presentation schemas. As in a presentation schema, counters must be defined
6207: in the <tt>COUNTERS</tt> section of the translation schema before they are
1.30 cvs 6208: used.</p>
6209:
6210: <p>When counters are used in a translation schema, the <tt>COUNTERS</tt>
1.37 cvs 6211: keyword is followed by the declarations of every counter used. Each
6212: declaration is composed of the counter's name possibly followed by a colon
6213: and the counting function to be used for the counter. The declaration is
1.30 cvs 6214: terminated by a semi-colon. If the counter is explicitely computed by
6215: <tt>Set</tt> and <tt>Add</tt> rules, no counting function is indicated. If a
6216: counting function is indicated, <tt>Set</tt> and <tt>Add</tt> rules cannot be
6217: applied to that counter.</p>
1.1 cvs 6218:
1.30 cvs 6219: <p>The counting function indicates how the counter's value will be computed.
1.18 cvs 6220: Three functions are available: <tt>Rank</tt>, <tt>Rlevel</tt>, and
6221: <tt>Set</tt>.</p>
6222: <ul>
1.40 quint 6223: <li><tt>Rank of ElemID</tt> indicates that the counter's value is the rank
6224: of the element of type <tt>ElemID</tt> which encloses the element for
6225: which the counter is being evaluated. For the purposes of this function,
6226: an element of type <tt>ElemID</tt> is considered to enclose itself. This
6227: function is primarily used when the element of type <tt>ElemID</tt> is
6228: part of an aggregate or list, in which case the counter's value is the
6229: element's rank in its list or aggregate. Note that, unlike the
6230: <tt>Rank</tt> function for presentation schemas, the <tt>Page</tt>
6231: keyword cannot be used in place of the <tt>ElemID</tt>.
1.37 cvs 6232: <p>The type name <tt>ElemID</tt> can be followed by an integer. That
6233: number represents the relative level, among the ancestors of the
6234: concerned element, of the element whose rank is asked. If that relative
6235: level <i>n</i> is unsigned, the <i>n<sup>th</sup></i> element of type
6236: <tt>ElemID</tt> encountered when travelling the logical structure from
6237: the root to the concerned element is taken into account. If the relative
1.30 cvs 6238: level is negative, the logical structure is travelled in the other
6239: direction, from the concerned element to the root.</p>
6240: </li>
1.40 quint 6241: <li><tt>Rlevel of ElemID</tt> indicates that the counter's values is the
6242: relative level in the tree of the element for which the counter is being
6243: evaluated. The counter counts the number of elements of type
6244: <tt>ElemID</tt> which are found on the path between the root of the
6245: document's logical structure tree and the element (inclusive).</li>
6246: <li><tt>Set n on Type1 Add m on Type2</tt> indicates that the counter's
6247: value is calculated as follows: in traversing the document from the
6248: beginning to the element for which the counter is being evaluated, the
6249: counter is set to the value <tt>n</tt> each time a <tt>Type1</tt> element
6250: is encountered and is incremented by the amount <tt>m</tt> each time a
6251: <tt>Type2</tt> element is encountered. The initial value <tt>n</tt> and
6252: the increment <tt>m</tt> are integers.</li>
1.30 cvs 6253: </ul>
6254:
6255: <p>As in a presentation schema, the <tt>Rank</tt> and <tt>Set</tt> functions
1.37 cvs 6256: can be modified by a numeric attribute which changes their initial value.
6257: This is indicated by the <tt>Init</tt> keyword followed by the numeric
6258: attribute's name. The <tt>Set</tt> function takes the value of the attribute
6259: instead of the <tt>InitValue</tt> (<tt>n</tt>). For the <tt>Rank</tt>
6260: function, the value of the attribute is considered to be the rank of the
6261: first element of the list (rather than the normal value of 1). Subsequent
6262: items in the list have their ranks shifted accordingly. In both cases, the
6263: attribute must be numeric and must be a local attribute of the root of the
6264: document itself.</p>
1.30 cvs 6265: <pre> CounterSeq = Counter < Counter > .
1.1 cvs 6266: Counter = CounterID [ ':' CounterFunc ] ';' .
6267: CounterID = NAME .
6268: CounterFunc = 'Rank' 'of' ElemID [ SLevelAsc ]
6269: [ 'Init' AttrID ] /
6270: 'Rlevel' 'of' ElemID /
6271: 'Set' InitValue 'On' ElemID
6272: 'Add' Increment 'On' ElemID
6273: [ 'Init' AttrID ] .
6274: SLevelAsc = [ '-' ] LevelAsc .
6275: LevelAsc = NUMBER .
6276: InitValue = NUMBER .
6277: Increment = NUMBER .
6278: ElemID = NAME .
1.18 cvs 6279: AttrID = NAME .</pre>
1.30 cvs 6280:
1.18 cvs 6281: <blockquote class="example">
1.30 cvs 6282: <p><strong>Example:</strong></p>
6283:
6284: <p>If the body of a chapter is defined in the structure schema by:</p>
6285: <pre>Chapter_Body = LIST OF
1.1 cvs 6286: (Section = BEGIN
6287: Section_Title = Text;
6288: Section_Body = BEGIN
6289: Paragraphs;
6290: Section;
6291: END;
6292: END
1.18 cvs 6293: );</pre>
1.30 cvs 6294:
6295: <p>(sections are defined recursively), a counter can be defined giving the
1.37 cvs 6296: <a name="sectnum" id="sectnum">number of a section</a> within its level in
6297: the hierarchy:</p>
1.30 cvs 6298: <pre>COUNTERS
1.18 cvs 6299: SectionNumber : Rank of Section;</pre>
1.30 cvs 6300:
6301: <p>A counter holding the hierarchic level of a section:</p>
6302: <pre> SectionLevel : Rlevel of Section;</pre>
6303:
1.37 cvs 6304: <p>A <a name="uniquenum" id="uniquenum">counter</a> which sequentially
6305: numbers all the document's sections, whatever their hierarchic level:</p>
1.30 cvs 6306: <pre> UniqueSectNum : Set 0 on Document Add 1 on Section;</pre>
1.18 cvs 6307: </blockquote>
6308: </div>
1.1 cvs 6309:
1.18 cvs 6310: <div class="subsection">
1.37 cvs 6311: <h3><a name="sectc525" id="sectc525">Constants</a></h3>
1.1 cvs 6312:
1.30 cvs 6313: <p>A common feature of translation rules is the generation of constant text.
1.37 cvs 6314: This text can be defined in the rule that generates it (see for example the
6315: <a href="#sectc5210"><tt>Create</tt></a> and <a
1.18 cvs 6316: href="#sectc5211"><tt>Write</tt></a> rules); but it can also be defined once
6317: in the constant declaration section and used many times in different rules.
1.37 cvs 6318: The latter option is preferable when the same text is used in several rules
6319: or several <a href="#sectc526">variables</a>.</p>
1.30 cvs 6320:
6321: <p>The <tt>CONST</tt> keyword begins the constant declaration section of the
1.37 cvs 6322: translation schema. It must be omitted if no constants are declared. Each
6323: constant declaration is composed of the constant name, an equals sign, and
6324: the constant's value, which is a character string between apostrophes. A
6325: constant declaration is terminated by a semicolon.</p>
1.30 cvs 6326: <pre> ConstSeq = Const < Const > .
1.1 cvs 6327: Const = ConstID '=' ConstValue ';' .
6328: ConstID = NAME .
1.18 cvs 6329: ConstValue = STRING .</pre>
1.30 cvs 6330:
1.18 cvs 6331: <blockquote class="example">
1.37 cvs 6332: <p><strong><a name="levelexample"
6333: id="levelexample">Example:</a></strong></p>
1.30 cvs 6334:
6335: <p>The following rule assigns the name <tt>TxtLevel</tt> to the character
6336: string ``Level'':</p>
6337: <pre>CONST
1.18 cvs 6338: TxtLevel = 'Level';</pre>
6339: </blockquote>
6340: </div>
1.1 cvs 6341:
1.18 cvs 6342: <div class="subsection">
1.37 cvs 6343: <h3><a name="sectc526" id="sectc526">Variables</a></h3>
1.1 cvs 6344:
1.30 cvs 6345: <p>Variables allow to define variable text which is generated by the
1.37 cvs 6346: <tt>Create</tt> and <tt>Write</tt> rules. They are also used to define file
1.18 cvs 6347: names which are used in the <tt>Create</tt>, <tt>ChangeMainFile</tt>,
1.37 cvs 6348: <tt>RemoveFile</tt>, and <tt>Indent</tt> rules. Variables can be defined
1.18 cvs 6349: either in the <tt>VAR</tt> section of the translation schema or directly in
1.37 cvs 6350: the rules which use them. Variables that define file names must be declared
1.18 cvs 6351: in the <tt>VAR</tt> section, and when the same variable is used several times
6352: in the translation schema, it makes sense to define it globally in the
1.37 cvs 6353: <tt>VAR</tt> section. This section is only present if at least one variable
1.18 cvs 6354: is defined globally.</p>
1.30 cvs 6355:
6356: <p>After the <tt>VAR</tt> keyword, each global variable is defined by its
6357: name, a colon separator and a sequence of functions (at least one function).
1.37 cvs 6358: Each variable definition is terminated by a semicolon. Functions determine
6359: the different parts which together give the value of the variable. The value
6360: is obtained by concatenating the strings produced by each of the functions.
6361: Seven types of functions are available. Each variable definition may use any
6362: number of functions of each type.</p>
1.18 cvs 6363: <ul>
1.30 cvs 6364: <li>The function <tt>Value(Counter)</tt>returns a string representing the
6365: value taken by the counter when it is evaluated for the element in whose
1.37 cvs 6366: rule the variable is used. The counter must have been declared in the
6367: <tt>COUNTERS</tt> section of the translation schema. When the counter is
1.30 cvs 6368: expressed in arabic numerals, the counter name can be followed by a colon
6369: and an integer indicating a minimum length (number of characters) for the
1.37 cvs 6370: string; if the counter's value is normally expressed with fewer
6371: characters than the required minimum, zeroes are added to the front of
6372: the string to achieve the minimum length.
1.30 cvs 6373: <p>By default, the counter value is written in arabic digits. If another
6374: representation of that value is needed, the counter name must be followed
6375: by a comma and one of the following keywords:</p>
6376: <ul>
1.40 quint 6377: <li><tt>Arabic</tt> : arabic numerals (default value),</li>
6378: <li><tt>LRoman</tt> : lower-case roman numerals,</li>
6379: <li><tt>URoman</tt> : upper-case roman numerals,</li>
6380: <li><tt>Uppercase</tt> : upper-case letter,</li>
6381: <li><tt>Lowercase</tt> : lower-case letter.</li>
1.30 cvs 6382: </ul>
6383: </li>
6384: <li>The function <tt>FileDir</tt>, without parameter, returns a string
6385: representing the name of the directory of the output file that has been
6386: given as a parameter to the translation program. The string includes a
6387: character '/' at the end.</li>
6388: <li>The function <tt>FileName</tt>, without parameter, returns a string
6389: representing the name of the output file that has been given as a
6390: parameter to the translation program. The file extension (the character
6391: string that terminate the file name, after a dot) is not part of that
6392: string.</li>
6393: <li>The function <tt>Extension</tt>, without parameter, returns a string
6394: representing the extension of the file name. That string is empty if the
6395: file name that has been given as a parameter to the translation program
6396: has no extension. If there is an extension, its first character is a
6397: dot.</li>
6398: <li>The function <tt>DocumentName</tt>, without parameter, returns a string
6399: representing the name of the document being translated.</li>
6400: <li>The function <tt>DocumentDir</tt>, without parameter, returns a string
6401: representing the directory containing the document being translated.</li>
6402: <li>The function formed by the name of a constant returns that constant's
6403: value.</li>
6404: <li>The function formed by a character string between apostrophes returns
6405: that string.</li>
1.37 cvs 6406: <li>The function formed by the name of a buffer returns the contents of
6407: that buffer. If the named buffer is the picture buffer, then the name of
6408: the last picture encountered is returned. Otherwise, the buffer is a read
1.31 cvs 6409: buffer and the value returned is text previously read from the terminal.
1.30 cvs 6410: If the buffer is empty (no picture has been encountered or the
6411: <tt>Read</tt> rule has not been executed for the buffer), then the empty
6412: string is returned.</li>
6413: <li>The function formed by an attribute name takes the value of the
1.37 cvs 6414: indicated attribute for the element to which the variable applies. If the
1.30 cvs 6415: element does not have that attribute, then the element's ancestor are
1.37 cvs 6416: searched toward the root of the tree. If one of the ancestors does have
6417: the attribute then its value is used. If no ancestors have the attribute,
1.30 cvs 6418: then the value of the function is the empty string.</li>
1.18 cvs 6419: </ul>
1.30 cvs 6420: <pre> VariableSeq = Variable < Variable > .
6421: Variable = VarID ':' Function < Function > ';' .
1.1 cvs 6422: VarID = NAME .
6423: Function ='Value' '(' CounterID [ ':' Length ]
6424: [ ',' CounterStyle ] ')' /
6425: 'FileDir' / 'FileName' / 'Extension' /
6426: 'DocumentName' / 'DocumentDir' /
6427: ConstID / CharString /
6428: BufferID / AttrID .
6429: Length = NUMBER .
6430: CounterStyle= 'Arabic' / 'LRoman' / 'URoman' /
6431: 'Uppercase' / 'Lowercase' .
1.18 cvs 6432: CharString = STRING .</pre>
1.30 cvs 6433:
1.18 cvs 6434: <blockquote class="example">
1.30 cvs 6435: <p><strong>Example:</strong></p>
6436:
6437: <p>To create, at the beginning of each section of the translated document,
6438: text composed of the string ``Section'' followed by the section number, the
1.37 cvs 6439: following <a name="varsectexample" id="varsectexample">variable
6440: definition</a> might be used:</p>
1.30 cvs 6441: <pre>VAR
1.18 cvs 6442: SectionVar : 'Section' Value(SectionNumber);</pre>
1.30 cvs 6443:
6444: <p>(see the definition of <a
6445: href="#sectnum"><tt>SectionNumber</tt></a>).</p>
6446:
1.37 cvs 6447: <p>The following variable definition can be used to create, at the
6448: beginning of each section, the text ``Level'' followed by the hierarchical
6449: level of the section. It used the constant defined above.</p>
1.30 cvs 6450: <pre> LevelVar : TxtLevel Value(SectionLevel);</pre>
6451:
6452: <p>(see the definitions of <a href="#sectnum"><tt>SectionLevel</tt></a> and
6453: of <a href="#levelexample"><tt>TxtLevel</tt></a>).</p>
6454:
6455: <p>To generate the translation of each section in a different file (see <a
1.37 cvs 6456: href="#sectc5220">rule <tt>ChangeMainFile</tt></a>), the name of these
6457: files might be defined by the following variable:</p>
1.30 cvs 6458: <pre> VarOutpuFile : FileName Value(SectionNumber)
1.18 cvs 6459: Extension;</pre>
1.30 cvs 6460:
1.37 cvs 6461: <p>If <tt>output.txt</tt> is the name of the <a name="varoutputfile"
6462: id="varoutputfile">output file</a> specified when starting the translation
6463: program, translated sections are written in files <tt>output1.txt</tt>,
6464: <tt>output2.txt</tt>, etc.</p>
1.18 cvs 6465: </blockquote>
6466: </div>
6467:
6468: <div class="subsection">
1.37 cvs 6469: <h3><a name="sectc527" id="sectc527">Translating structure elements</a></h3>
1.18 cvs 6470:
1.30 cvs 6471: <p>The <tt>RULES</tt> keyword introduces the translation rules which will be
1.37 cvs 6472: applied to the various structured element types. Translation rules can be
6473: specified for each element type defined in the structure schema, including
6474: the base types defined implicitly, whose names are <tt>TEXT_UNIT</tt>,
1.18 cvs 6475: <tt>PICTURE_UNIT</tt>, <tt>SYMBOL_UNIT</tt>, <tt>GRAPHIC_UNIT</tt> and
1.37 cvs 6476: <tt>PAGE_UNIT</tt>. But it is not necessary to specify rules for every
1.18 cvs 6477: defined type.</p>
1.30 cvs 6478:
1.37 cvs 6479: <p>If there are no translation rules for an element type, the elements that
6480: it contains (and which may have rules themselves) will still be translated,
6481: but the translator will produce nothing for the element itself. To make the
1.18 cvs 6482: translator completely ignore the content of an element the <a
6483: href="#sectc5217"><tt>Remove</tt> rule</a> must be used.</p>
1.30 cvs 6484:
6485: <p>The translation rules for an element type defined in the structure schema
6486: are written using the name of the type followed by a colon and the list of
1.37 cvs 6487: applicable rules. When the element type is a <a href="#sectd3285">mark
1.18 cvs 6488: pair</a>, but only in this case, the type name must be preceded by the
1.37 cvs 6489: <tt>First</tt> or <tt>Second</tt> keyword. This keyword indicates whether the
1.18 cvs 6490: rules that follow apply to the first or second mark of the pair.</p>
1.30 cvs 6491:
1.37 cvs 6492: <p>The list of rules can take several forms. It may be a simple
6493: non-conditional rule. It can also be formed by a condition followed by one or
6494: more simple rules. Or it can be a block of rules beginning with the
1.30 cvs 6495: <tt>BEGIN</tt> keyword and ending with the <tt>END</tt> keyword and a
1.37 cvs 6496: semicolon. This block of rules can contain one or more simple rules and/or
1.30 cvs 6497: one or more conditions, each followed by one or more simple rules.</p>
6498: <pre> ElemSeq = TransType < TransType > .
1.1 cvs 6499: TransType = [ FirstSec ] ElemID ':' RuleSeq .
6500: FirstSec = 'First' / 'Second' .
1.30 cvs 6501: RuleSeq = Rule / 'BEGIN' < Rule > 'END' ';' .
1.1 cvs 6502: Rule = SimpleRule / ConditionBlock .
6503: ConditionBlock = 'IF' ConditionSeq SimpleRuleSeq .
1.30 cvs 6504: SimpleRuleSeq = 'BEGIN' < SimpleRule > 'END' ';' /
1.18 cvs 6505: SimpleRule .</pre>
6506: </div>
1.1 cvs 6507:
1.18 cvs 6508: <div class="subsection">
1.37 cvs 6509: <h3><a name="sectc528" id="sectc528">Conditional rules</a></h3>
1.1 cvs 6510:
1.30 cvs 6511: <p>In a translation schema, the translation rules are either associated with
1.37 cvs 6512: element types or with attribute values or with a specific presentation. They
1.1 cvs 6513: are applied by the translator each time an element of the corresponding type
6514: is encountered in the translated document or each time the attribute value is
6515: carried by an element or also, each time the specific translation is attached
1.37 cvs 6516: to an element. This systematic application of the rules can be relaxed: it is
6517: possible to add a condition to one or more rules, so that these rules are
6518: only applied when the condition is true.</p>
1.30 cvs 6519:
6520: <p>A condition begins with the keyword <tt>IF</tt>, followed by a sequence of
1.37 cvs 6521: elementary conditions. Elementary conditions are separated from each other by
6522: the <tt>AND</tt> keyword. If there is only one elementary condition, this
6523: keyword is absent. The rules are only applied if all the elementary
6524: conditions are true. The elementary condition can be negative; it is then
1.18 cvs 6525: preceded by the <tt>NOT</tt> keyword.</p>
1.30 cvs 6526:
6527: <p>When the translation rule(s) controlled by the condition apply to a
6528: reference element or a reference attribute, an elementary condition can also
1.37 cvs 6529: apply to element referred by this reference. The <tt>Target</tt> keyword is
6530: used for that purpose. It must appear before the keyword defining the
1.30 cvs 6531: condition type.</p>
6532:
6533: <p>Depending on their type, some conditions may apply either to the element
1.37 cvs 6534: with which they are associated, or to one of its ancestor. In the case of an
1.18 cvs 6535: ancestor, the key word <tt>Ancestor</tt> must be used, followed by</p>
6536: <ul>
1.30 cvs 6537: <li>either an integer which represents the number of levels in the tree
6538: between the element and the ancestor of interest,</li>
1.37 cvs 6539: <li>or the type name of the ancestor of interest. If that type is defined
1.30 cvs 6540: in a separate structure schema, the name of that schema must follow
6541: between parentheses.</li>
1.18 cvs 6542: </ul>
1.30 cvs 6543:
1.37 cvs 6544: <p>There is a special case for the parent element, which can be simply
6545: written <tt>Parent</tt> instead of <tt>Ancestor 1</tt>.</p>
1.30 cvs 6546:
6547: <p>Only conditions <tt>First</tt>, <tt>Last</tt>, <tt>Referred</tt>,
1.34 cvs 6548: <tt>Within</tt>, <tt>Attributes</tt>, <tt>Presentation</tt>, and those
6549: concerning an attribute or a specific presentation can apply to an ancestor.
6550: Conditions <tt>FirstRef</tt>, <tt>LastRef</tt>, <tt>ExternalRef</tt>,
1.41 vatton 6551: <tt>Script</tt>, <tt>FirstAttr</tt>, <tt>LastAttr</tt>,
1.34 cvs 6552: <tt>ComputedPage</tt>, <tt>StartPage</tt>, <tt>UserPage</tt>,
6553: <tt>ReminderPage</tt>, <tt>Empty</tt> cannot be preceded by keywords
6554: <tt>Parent</tt> or <tt>Ancestor</tt>.</p>
1.30 cvs 6555:
1.37 cvs 6556: <p>In condition <tt>Referred</tt> and in the condition that applies to a
6557: named attribute, a symbol '<tt>*</tt>' can indicate that the condition is
6558: related only to the element itself. If this symbol is not present, not only
6559: the element is considered, but also its ancestor, at any level.</p>
1.30 cvs 6560:
6561: <p>The form of an elementary condition varies according to the type of
1.18 cvs 6562: condition.</p>
1.1 cvs 6563:
1.18 cvs 6564: <div class="subsubsection">
1.37 cvs 6565: <h4><a name="sectd5281" id="sectd5281">Conditions based on the logical
6566: position of the element</a></h4>
1.30 cvs 6567:
6568: <p>The condition can be on the position of the element in the document's
1.37 cvs 6569: logical structure tree. It is possible to test whether the element is the
1.30 cvs 6570: first (<tt>First</tt>) or last (<tt>Last</tt>) among its siblings or if it is
6571: not the first (<tt>NOT First</tt>) or not the last (<tt>NOT Last</tt>).</p>
6572:
6573: <p>It is also possible to test if the element is contained in an element of a
1.18 cvs 6574: given type (<tt>Within</tt>) or if it is not (<tt>NOT Within</tt>). If that
1.1 cvs 6575: element type is defined in a structure schema which is not the one which
6576: corresponds to the translation schema, the type name of this element must be
6577: followed, between parentheses, by the name of the structure schema which
1.18 cvs 6578: defines it.</p>
1.30 cvs 6579:
6580: <p>If the keyword <tt>Within</tt> is preceded by <tt>Immediately</tt>, the
1.18 cvs 6581: condition is satisfied only if the <em>parent</em> element has the type
6582: indicated. If the word <tt>Immediately</tt> is missing, the condition is
6583: satisfied if any <em>ancestor</em> has the type indicated.</p>
1.30 cvs 6584:
6585: <p>An integer <i>n</i> can appear between the keyword <tt>Within</tt> and the
1.37 cvs 6586: type. It specifies the number of ancestors of the indicated type that must be
6587: present for the condition to be satisfied. If the keyword
1.18 cvs 6588: <tt>Immediately</tt> is also present, the <i>n</i> immediate ancestors of the
1.37 cvs 6589: element must have the indicated type. The integer <i>n</i> must be positive
6590: or zero. It can be preceded by <tt><</tt> or <tt>></tt> to indicate a
6591: maximum or minimum number of ancestors. If these symbols are missing, the
6592: condition is satisfied only if it exists exactly <i>n</i> ancestors. When
1.30 cvs 6593: this number is missing, it is equivalent to > 0.</p>
6594:
1.37 cvs 6595: <p>If the condition applies to translation rules associated with an
6596: attribute, i.e. if it is in the <tt>ATTRIBUTES</tt> section of the
6597: presentation schema, the condition can be simply an element name. Translation
6598: rules are then executed only if the attribute is attached to an element of
6599: that type. The keyword <tt>NOT</tt> before the element name indicates that
6600: the translation rules must be executed only if the element is not of the type
6601: indicated.</p>
1.18 cvs 6602: </div>
1.1 cvs 6603:
1.18 cvs 6604: <div class="subsubsection">
1.37 cvs 6605: <h4><a name="sectd5282" id="sectd5282">Conditions on references</a></h4>
1.1 cvs 6606:
1.30 cvs 6607: <p>References may be taken into account in conditions, which can be based on
6608: the fact that the element, or one of its ancestors (unless symbol <tt>*</tt>
6609: is present), is designated by a at least one reference (<tt>Referred</tt>) or
1.37 cvs 6610: by none (<tt>NOT Referred</tt>). If the element or attribute to which the
1.1 cvs 6611: condition is attached is a reference, the condition can be based on the fact
6612: that it acts as the first reference to the designated element
1.18 cvs 6613: (<tt>FirstRef</tt>), or as the last (<tt>LastRef</tt>), or as a reference to
1.37 cvs 6614: an element located in another document (<tt>ExternalRef</tt>). Like all
1.18 cvs 6615: conditions, conditions on references can be inverted by the <tt>NOT</tt>
6616: keyword.</p>
6617: </div>
6618:
6619: <div class="subsubsection">
1.41 vatton 6620: <h4><a name="sectd5284" id="sectd5284">Conditions on the scripts</a></h4>
1.1 cvs 6621:
1.30 cvs 6622: <p>The character string base type (and only this type) can use the condition
1.43 quint 6623: <tt>Script = a</tt> which indicates that the translation rule(s) should only
6624: apply if the script of the character string is the one whose name appears
6625: after the equals sign (or is not, if there is a preceding <tt>NOT</tt>
6626: keyword). This condition cannot be applied to translation rules of an
6627: attribute.</p>
1.30 cvs 6628:
1.41 vatton 6629: <p>In the current implementation of Thot, the available scripts are the
6630: <tt>Latin</tt> script and the <tt>Greek</tt> script.</p>
1.18 cvs 6631: </div>
1.1 cvs 6632:
1.18 cvs 6633: <div class="subsubsection">
1.37 cvs 6634: <h4><a name="sectd5285" id="sectd5285">Conditions on page breaks</a></h4>
1.1 cvs 6635:
1.30 cvs 6636: <p>The page break base type (and only this type) can use the following
1.18 cvs 6637: conditions: <tt>ComputedPage</tt>, <tt>StartPage</tt>, <tt>UserPage</tt>, and
1.37 cvs 6638: <tt>ReminderPage</tt>. The <tt>ComputedPage</tt> condition indicates that the
1.1 cvs 6639: translation rule(s) should apply if the page break was created automatically
1.37 cvs 6640: by Thot; the <tt>StartPage</tt> condition is true if the page break is
1.18 cvs 6641: generated before the element by the <tt>Page</tt> rule of the P language; the
6642: <tt>UserPage</tt> condition applies if the page break was inserted by the
1.37 cvs 6643: user; and the <tt>ReminderPage</tt> is applied if the page break is a
6644: reminder of page breaking.</p>
1.18 cvs 6645: </div>
1.1 cvs 6646:
1.18 cvs 6647: <div class="subsubsection">
1.37 cvs 6648: <h4><a name="sectd5286" id="sectd5286">Conditions on the element's
6649: content</a></h4>
1.1 cvs 6650:
1.37 cvs 6651: <p>The condition can be based on whether or not the element is empty. An
1.30 cvs 6652: element which has no children or whose leaves are all empty is considered to
1.37 cvs 6653: be empty itself. This condition is expressed by the <tt>Empty</tt> keyword,
1.30 cvs 6654: optionally preceded by the <tt>NOT</tt> keyword.</p>
1.18 cvs 6655: </div>
1.1 cvs 6656:
1.18 cvs 6657: <div class="subsubsection">
1.37 cvs 6658: <h4><a name="sectd5288" id="sectd5288">Conditions on the presence of specific
6659: presentation rules</a></h4>
1.30 cvs 6660:
6661: <p>The condition can be based on the presence or absence of specific
1.37 cvs 6662: presentation rules associated with the translated element, whatever the
6663: rules, their value or their number. This condition is expressed by the
6664: keyword <tt>Presentation</tt>, optionally preceded by the <tt>NOT</tt>
6665: keyword.</p>
1.18 cvs 6666: </div>
1.1 cvs 6667:
1.18 cvs 6668: <div class="subsubsection">
1.37 cvs 6669: <h4><a name="sectd5289" id="sectd5289">Conditions on the presence of logical
1.18 cvs 6670: attributes</a></h4>
1.30 cvs 6671:
6672: <p>In the same way, the condition can be based on the presence or absence of
1.1 cvs 6673: attributes associated with the translated elements, no matter what the
1.37 cvs 6674: attributes or their values. The <tt>Attributes</tt> keyword expresses this
1.18 cvs 6675: condition.</p>
6676: </div>
1.1 cvs 6677:
1.18 cvs 6678: <div class="subsubsection">
1.37 cvs 6679: <h4><a name="sectd52810" id="sectd52810">Conditions on logical
6680: attributes</a></h4>
1.1 cvs 6681:
1.30 cvs 6682: <p>If the condition appears in the translation rules of an attribute, the
1.37 cvs 6683: <tt>FirstAttr</tt> and <tt>LastAttr</tt> keywords can be used to indicate
6684: that the rules must only be applied if this attribute is the first attribute
6685: for the translated element or if it is the last (respectively). These
6686: conditions can also be inverted by the <tt>NOT</tt> keyword.</p>
6687:
6688: <p>Another type of condition can only be applied to the translation rules
6689: when the element being processed (or one of its ancestors if symbol
6690: <tt>*</tt> is missing) has a certain attribute, perhaps with a certain value
6691: or, in contrast, when the element does not have this attribute with this
6692: value. The condition is specified by writing the name of the attribute after
6693: the keyword <tt>IF</tt> or <tt>AND</tt>. The <tt>NOT</tt> keyword can be used
6694: to invert the condition. If the translation rules must be applied to any
6695: element which has this attribute (or does not have it, if the condition is
6696: inverted) no matter what the attribute's value, the condition is complete.
6697: If, in contrast, the condition applies to one or more values of the
6698: attribute, these are indicated after the name of the attribute, except for
6699: reference attributes which do not have values.</p>
6700:
6701: <p>The representation of the values of an <a name="relattr"
6702: id="relattr">attribute</a> in a condition depends on the attribute's type.
6703: For attributes with enumerated or textual types, the value (a name or
6704: character string between apostrophes, respectively) is simply preceded by an
6705: equals sign. For numeric attributes, the condition can be based on a single
6706: value or on a range of values. In the case of a unique value, this value (an
6707: integer) is simply preceded by an equals sign. Conditions based on ranges of
6708: values have several forms:</p>
1.18 cvs 6709: <ul>
1.30 cvs 6710: <li>all values less than a given value (the value is preceded by a ``less
6711: than'' sign).</li>
6712: <li>all values greater than a given value (the value is preceded by a
6713: ``greater than'' sign).</li>
1.37 cvs 6714: <li>all values falling in an interval, bounds included. The range of values
6715: is then specified <tt>IN [</tt>Minimum <tt>..</tt>Maximum<tt>]</tt>,
6716: where Minimum and Maximum are integers.</li>
1.18 cvs 6717: </ul>
1.30 cvs 6718:
1.37 cvs 6719: <p>All numeric values may be negative. The integer is simply preceded by a
1.30 cvs 6720: minus sign.</p>
6721:
6722: <p>Both local and global attributes can be used in conditions.</p>
1.18 cvs 6723: </div>
1.1 cvs 6724:
1.18 cvs 6725: <div class="subsubsection">
1.37 cvs 6726: <h4><a name="sectd52811" id="sectd52811">Conditions on specific presentation
6727: rules</a></h4>
1.1 cvs 6728:
1.30 cvs 6729: <p>It is possible to apply translation rules only when the element being
1.1 cvs 6730: processed has or does not have a specific presentation rule, possibly with a
1.37 cvs 6731: certain value. The condition is specified by writing the name of the
6732: presentation rule after the keyword <tt>IF</tt> or <tt>AND</tt>. The
6733: <tt>NOT</tt> keyword can be used to invert the condition. If the translation
6734: rules must be applied to any element which has this presentation rule (or
6735: does not have it, if the condition is inverted) no matter what the rule's
6736: value, the condition is complete. If, in contrast, the condition applies to
6737: one or more values of the rule, these are indicated after the name of the
1.18 cvs 6738: attribute.</p>
1.30 cvs 6739:
1.37 cvs 6740: <p>The representation of presentation rule values in a condition is similar
6741: to that for attribute values. The representation of these values depend on
6742: the type of the presentation rule. There are three categories of presentation
1.18 cvs 6743: rules:</p>
6744: <ul>
1.30 cvs 6745: <li>those taking numeric values (<tt>Size, Indent, LineSpacing,
6746: LineWeight</tt>),</li>
1.36 cvs 6747: <li>those with values taken from a predefined list (<tt>Adjust, Hyphenate,
1.43 quint 6748: Direction, UnicodeBidi, Style, Weight, Font, UnderLine, Thickness,
6749: LineStyle</tt>),</li>
1.30 cvs 6750: <li>those whose value is a name (<tt>FillPattern, Background,
6751: Foreground</tt>).</li>
1.18 cvs 6752: </ul>
1.30 cvs 6753:
6754: <p>For presentation rules which take numeric values, the condition can take a
1.37 cvs 6755: unique value or a range of values. In the case of a unique value, this value
1.1 cvs 6756: (an integer) is simply preceded by an equals sign. Conditions based on ranges
1.18 cvs 6757: of values have several forms:</p>
6758: <ul>
1.30 cvs 6759: <li>all values less than a given value (the value is preceded by a ``less
6760: than'' sign).</li>
6761: <li>all values greater than a given value (the value is preceded by a
6762: ``greater than'' sign).</li>
1.37 cvs 6763: <li>all values falling in an interval, bounds included. The range of values
6764: is then specified <tt>IN [</tt>Minimum <tt>..</tt>Maximum<tt>]</tt>,
6765: where Minimum and Maximum are integers.</li>
1.18 cvs 6766: </ul>
1.30 cvs 6767:
1.37 cvs 6768: <p>Values for the <tt>Indent</tt>rule may be negative. The integer is then
1.2 cvs 6769: simply preceded by a minus sign and represents how far the first line starts
1.18 cvs 6770: to the left of the other lines.</p>
1.30 cvs 6771:
6772: <p>For presentation rules whose values are taken from predefined lists, the
1.37 cvs 6773: value which satisfies the condition is indicated by an equals sign followed
6774: by the name of the value.</p>
1.30 cvs 6775:
1.37 cvs 6776: <p>For presentation rule whose values are names, the value which satisfies
6777: the condition is indicated by the equals sign followed by the value's name.
6778: The names of fill patterns (the <tt>FillPattern</tt> rule) and of colors (the
1.18 cvs 6779: <tt>Foreground</tt> and <tt>Background</tt> rules) known to Thot are the same
6780: as in the P language.</p>
1.30 cvs 6781:
6782: <p>The syntax of conditions based on the specific presentation is the same as
6783: the syntax used to express the <a href="#sectc5224">translation of specific
1.18 cvs 6784: presentation rules</a>.</p>
1.30 cvs 6785:
6786: <p>When a condition has only one rule, the condition is simply followed by
1.37 cvs 6787: that rule. If it has several rules, they are placed after the condition
1.30 cvs 6788: between the keywords <tt>BEGIN</tt> and <tt>END</tt>.</p>
1.18 cvs 6789: <pre> ConditionSeq = Condition [ 'AND' Condition ] .
1.1 cvs 6790: Condition = [ 'NOT' ] [ 'Target' ] Cond .
6791: Cond = CondElem / CondAscend .
6792: CondElem ='FirstRef' / 'LastRef' /
6793: 'ExternalRef' /
1.41 vatton 6794: 'Script' '=' Script /
1.1 cvs 6795: 'ComputedPage' / 'StartPage' /
6796: 'UserPage' / 'ReminderPage' /
6797: 'Empty' /
1.11 cvs 6798: ElemID /
1.1 cvs 6799: 'FirstAttr' / 'LastAttr' .
6800: CondAscend = [ Ascend ] CondOnAscend .
6801: Ascend = '*' / 'Parent' / 'Ancestor' LevelOrType .
6802: LevelOrType = CondRelLevel / ElemID [ ExtStruct ] .
6803: CondRelLevel = NUMBER .
6804: CondOnAscend ='First' / 'Last' /
6805: 'Referred' /
6806: [ 'Immediately' ] 'Within' [ NumParent ]
6807: ElemID [ ExtStruct ] /
6808: 'Attributes' /
6809: AttrID [ RelatAttr ] /
6810: 'Presentation' /
1.34 cvs 6811: PresRule .
1.1 cvs 6812: NumParent = [ GreaterLess ] NParent .
1.30 cvs 6813: GreaterLess = '>' / '<' .
1.1 cvs 6814: NParent = NUMBER.
6815: ExtStruct = '(' ElemID ')' .
1.41 vatton 6816: Script = NAME .
1.1 cvs 6817: RelatAttr ='=' Value /
1.30 cvs 6818: '>' [ '-' ] Minimum /
1.1 cvs 6819: '<' [ '-' ] Maximum /
6820: 'IN' '[' [ '-' ] MinInterval '..'
6821: [ '-' ] MaxInterval ']' .
6822: Value = [ '-' ] IntegerVal / TextVal / AttrValue .
6823: Minimum = NUMBER .
6824: Maximum = NUMBER .
6825: MinInterval = NUMBER .
6826: MaxInterval = NUMBER .
6827: IntegerVal = NUMBER .
6828: TextVal = STRING .
1.18 cvs 6829: AttrValue = NAME .</pre>
1.30 cvs 6830:
1.18 cvs 6831: <blockquote class="example">
1.30 cvs 6832: <p><strong>Example:</strong></p>
6833:
6834: <p>Suppose that after each element of type Section_Title it is useful to
6835: produce the text <tt>\label{SectX}</tt> where <tt>X</tt> represents the
6836: section number, but only if the section is designated by one or more
1.37 cvs 6837: references in the document. The following conditional rule produces this
1.30 cvs 6838: effect:</p>
6839: <pre>RULES
1.1 cvs 6840: Section_Title :
6841: IF Referred
1.18 cvs 6842: Create ('\label{Sect' Value(UniqueSectNum) '}\12') After;</pre>
1.30 cvs 6843:
6844: <p>(the declaration of the <a href="#sectc5224"><tt>UniqueSectNum</tt>
1.37 cvs 6845: counter</a> is given above). The string <tt>\12</tt> represents a line
1.30 cvs 6846: break.</p>
1.18 cvs 6847: </blockquote>
1.30 cvs 6848:
1.18 cvs 6849: <blockquote class="example">
1.30 cvs 6850: <p><strong>Example:</strong></p>
6851:
1.37 cvs 6852: <p>Suppose that for elements of the Elmnt type it would be useful to
6853: produce a character indicating the value of the numeric attribute Level
6854: associated with the element: an ``A'' for all values of Level less than 3,
6855: a ``B'' for values between 3 and 10 and a ``C'' for values greater than 10.
6856: This can be achieved by writing the following rules for the Elmnt type:</p>
1.30 cvs 6857: <pre>RULES
1.1 cvs 6858: Elmnt :
6859: BEGIN
6860: IF Level < 3
6861: Create 'A';
6862: IF Level IN [3..10]
6863: Create 'B';
1.30 cvs 6864: IF Level > 10
1.1 cvs 6865: Create 'C';
1.18 cvs 6866: END;</pre>
6867: </blockquote>
6868: </div>
6869: </div>
1.1 cvs 6870:
1.18 cvs 6871: <div class="subsection">
1.37 cvs 6872: <h3><a name="sectc529" id="sectc529">Translation rules</a></h3>
1.1 cvs 6873:
1.37 cvs 6874: <p>Fifteen types of translation rules can be associated with element types
6875: and attribute values. They are the <tt>Create</tt>, <tt>Write</tt>,
1.18 cvs 6876: <tt>Read</tt>, <tt>Include</tt>, <tt>Get</tt>, <tt>Copy</tt>, <tt>Use</tt>,
1.31 cvs 6877: <tt>Remove</tt>, <tt>Ignore</tt>, <tt>NoTranslation</tt>,
6878: <tt>NoLineBreak</tt>, <tt>ChangeMainFile</tt>, <tt>RemoveFile</tt>,
1.37 cvs 6879: <tt>Set</tt>, <tt>Add</tt>, <tt>Indent</tt>, rules. Each rule has its own
1.31 cvs 6880: syntax, although they are all based on very similar models.</p>
1.18 cvs 6881: <pre> SimpleRule = 'Create' [ 'IN' VarID ] Object
1.1 cvs 6882: [ Position ] ';' /
6883: 'Write' Object [ Position ] ';' /
6884: 'Read' BufferID [ Position ] ';' /
6885: 'Include' File [ Position ] ';' /
6886: 'Get' [ RelPosition ] ElemID
6887: [ ExtStruct ]
6888: [ Position ] ';' /
6889: 'Copy' [ RelPosition ] ElemID
6890: [ ExtStruct ]
6891: [ Position ] ';' /
6892: 'Use' TrSchema [ 'For' ElemID ] ';' /
6893: 'Remove' ';' /
1.31 cvs 6894: 'Ignore' ';' /
1.1 cvs 6895: 'NoTranslation' ';' /
6896: 'NoLineBreak' ';' /
6897: 'ChangeMainFile' VarID [ Position ] ';' /
1.14 cvs 6898: 'RemoveFile' VarID [ Position ] ';' /
1.10 cvs 6899: 'Set' CounterID InitValue [ Position ] ';' /
6900: 'Add' CounterID Increment [ Position ] ';' /
1.25 cvs 6901: 'Indent' [ 'IN' VarID ] Indent [ Position ] ';' .</pre>
1.18 cvs 6902: </div>
6903:
6904: <div class="subsection">
1.37 cvs 6905: <h3><a name="sectc5210" id="sectc5210">The <tt>Create</tt> rule</a></h3>
1.18 cvs 6906:
1.30 cvs 6907: <p>The most frequently used rule is undoubtedly the <tt>Create</tt> rule,
6908: which generates fixed or variable text (called an <em>object</em>) in the
1.37 cvs 6909: output file. The generated text can be made to appear either before or after
6910: the content of the element to which the rule applies. The rule begins with
6911: the <tt>Create</tt> keyword, followed by a specifier for the object and a
6912: keyword (<tt>Before</tt> or <tt>After</tt>) indicating the position of the
6913: generated text (<a href="#sectc5222">before or after</a> the element's
6914: content). If the position is not indicated, the object will be generated
6915: before the element's content. This rule, like all translation rules, is
6916: terminated by a semicolon.</p>
1.30 cvs 6917:
6918: <p>The <tt>Create</tt> keyword can be followed by the <tt>IN</tt> keyword and
1.37 cvs 6919: by the name of a variable. This means that the text generated by the rule
1.30 cvs 6920: must not be written in the main output file, but in the file whose name is
1.18 cvs 6921: specified by the variable.</p>
1.30 cvs 6922:
6923: <p>This allows the translation program to generate text in different files
6924: during the same run. These files do not need to be explicitely declared or
6925: opened. They do not need to be closed either, but if they contain temporary
6926: data, they can be removed (see the <a href="#sectc5220a"><tt>RemoveFile</tt>
6927: rule</a>). As soon as the translation program executes a <tt>Create</tt> rule
6928: for a file that is not yet open, it opens the file. These files are closed
6929: when the translation is finished.</p>
1.18 cvs 6930: <pre> 'Create' [ 'IN' VarID ] Object
1.1 cvs 6931: [ Position ] ';'
6932: Object = ConstID / CharString /
6933: BufferID /
6934: VarID /
1.30 cvs 6935: '(' Function < Function > ')' /
1.21 cvs 6936: [ 'Translated' ] AttrID /
1.1 cvs 6937: 'Value' /
6938: 'Content' /
6939: 'Attributes' /
6940: 'Presentation' /
6941: 'RefId' /
6942: 'PairId' /
6943: 'FileDir' /
6944: 'FileName' /
6945: 'Extension' /
6946: 'DocumentName' /
6947: 'DocumentDir' /
6948: [ 'Referred' ] ReferredObject .
6949: Position ='After' / 'Before' .
6950:
6951: ReferredObject = VarID /
6952: ElemID [ ExtStruct ] /
6953: 'RefId' /
6954: 'DocumentName' /
1.18 cvs 6955: 'DocumentDir' .</pre>
1.30 cvs 6956:
6957: <p>The object to be generated can be:</p>
1.18 cvs 6958: <ul>
1.30 cvs 6959: <li>a constant string, specified by its name if it is declared in the
6960: schema's <tt>CONST</tt> section, or given directly as a value between
6961: apostrophes;</li>
6962: <li>the contents of a buffer, designated by the name of the buffer;</li>
6963: <li>a variable, designated by its name if it is declared in the translation
1.37 cvs 6964: schema's <tt>VAR</tt> section, or given directly between parentheses. The
1.30 cvs 6965: text generated is the value of that variable evaluated for the element to
6966: which the rule applies.</li>
6967: <li>the value of an attribute, if the element being translated has this
6968: attribute. The attribute is specified by its name. If it's a text
6969: attribute, it can be preceded by the <code>Translated</code> keyword,
6970: which causes the attribute value to be recoded using the text translation
6971: table defined by section <code><a
6972: href="#sectc5225">TEXTTRANSLATE</a></code>;</li>
1.37 cvs 6973: <li>the value of a specific presentation rule. This object can only be
1.30 cvs 6974: generated if the translation rule is for a <a href="#prestransl">specific
1.37 cvs 6975: presentation rule</a>. It is specified by the <tt>Value</tt> keyword;</li>
6976: <li>the element's content. That is, the content of the leaves of the
6977: subtree of the translated element. This is specified by the
1.30 cvs 6978: <tt>Content</tt> keyword;</li>
6979: <li>the translation of all attributes of the element (which is primarily
6980: used to apply the attribute translation rules <a
1.37 cvs 6981: href="#sectc5222">before</a> those of the element type). This is
1.30 cvs 6982: specified by the <tt>Attributes</tt> keyword.</li>
6983: <li>the translation of all of the element's specific presentation rules
6984: (which is primarily used to apply the translation rules for the specific
1.37 cvs 6985: presentation rules <a href="#sectc5222">before</a> those of the element
6986: or its attributes). This option is specified by the <tt>Presentation</tt>
1.30 cvs 6987: keyword;</li>
1.37 cvs 6988: <li>The value of the reference's identifier.<br />
6989: Thot associates a unique identifier with each element in a document. This
6990: identifier (called <em>reference's identifier</em> or <em>label</em>) is
6991: a character string containing the letter `L' followed by digits. Thot
6992: uses it in references for identifying the referred element.<br />
1.30 cvs 6993: The <tt>RefId</tt> keyword produces the reference's identifier of the
6994: element to which the translation rule is applied, or the reference's
6995: identifier of its first ancestor that is referred by a reference or that
6996: can be referred by a reference.</li>
1.37 cvs 6997: <li>the value of a mark pair's unique identifier. This may only be used for
1.30 cvs 6998: <a href="#sectd3285">mark pairs</a> and is indicated by the
6999: <tt>PairId</tt> keyword.</li>
7000: <li>the directory containing the file being generated (this string includes
1.37 cvs 7001: an ending '/', if it is not empty). This is indicated by the
1.30 cvs 7002: <tt>FileDir</tt> keyword.</li>
7003: <li>the name of the file being generated (only the name, without the
7004: directory and without the extension). This is indicated by the
7005: <tt>FileName</tt> keyword.</li>
7006: <li>the extension of the file being generated (this string starts with a
1.37 cvs 7007: dot, if it is not empty). This is indicated by the <tt>Extension</tt>
1.30 cvs 7008: keyword.</li>
1.37 cvs 7009: <li>the name of the document being translated. This is indicated by the
1.30 cvs 7010: <tt>DocumentName</tt> keyword.</li>
1.37 cvs 7011: <li>the directory containing the document being translated. This is
1.30 cvs 7012: indicated by the <tt>DocumentDir</tt> keyword.</li>
1.18 cvs 7013: </ul>
1.30 cvs 7014:
1.37 cvs 7015: <p>When the rule applies to a reference (an element or an attribute defined
7016: as a reference in the structure schema), it can generate a text related to
7017: the element referred by that reference. The rule name is then followed by the
1.18 cvs 7018: <tt>Referred</tt> keyword and a specification of the object to be generated
1.37 cvs 7019: for the referred element. This specification can be:</p>
1.18 cvs 7020: <ul>
1.37 cvs 7021: <li>the name of a variable. The rule generates the value of that variable,
1.30 cvs 7022: computed for the referred element.</li>
1.37 cvs 7023: <li>an element type. The rule generates the translation of the element of
7024: that type, which is in the subtree of the referred element. If this
1.30 cvs 7025: element is not defined in the structure schema which corresponds to the
7026: translation schema (that is, an object defined in another schema), the
7027: element's type name must be followed by the name of its structure schema
7028: between parentheses.</li>
1.37 cvs 7029: <li>the <tt>RefId</tt> keyword. The rule generates the reference's
1.30 cvs 7030: identifier of the referred element.</li>
1.37 cvs 7031: <li>the <tt>DocumentName</tt> keyword. The rule generates the name of the
1.30 cvs 7032: document to which the referred element belongs.</li>
1.37 cvs 7033: <li>the <tt>DocumentDir</tt> keyword. The rule generates the name of the
1.30 cvs 7034: directory that contains the document of the referred element.</li>
1.18 cvs 7035: </ul>
7036: </div>
1.1 cvs 7037:
1.18 cvs 7038: <div class="subsection">
1.37 cvs 7039: <h3><a name="sectc5211" id="sectc5211">The <tt>Write</tt> rule</a></h3>
1.1 cvs 7040:
1.37 cvs 7041: <p>The <tt>Write</tt> has the same syntax as the <tt>Create</tt> rule. It
1.30 cvs 7042: also produces the same effect, but the generated text is displayed on the
7043: user's terminal during the translation of the document, instead of being
1.37 cvs 7044: produced in the translated document. This is useful for helping the user keep
1.30 cvs 7045: track of the progress of the translation and for prompting the user on the
7046: terminal for input required by the <tt>Read</tt> rule.</p>
1.18 cvs 7047: <pre> 'Write' Object [ Position ] ';'</pre>
1.30 cvs 7048:
7049: <p>Notice: if the translator is launched by the editor (by the ``Save as''
1.18 cvs 7050: command), messages produced by the <tt>Write</tt> rule are not displayed.</p>
1.30 cvs 7051:
1.18 cvs 7052: <blockquote class="example">
1.30 cvs 7053: <p><strong>Example:</strong></p>
7054:
7055: <p>To make the translator display the number of each section being
7056: translated on the user's terminal, the following rule is specified for the
7057: <tt>Section</tt> element type:</p>
7058: <pre>Section : BEGIN
1.1 cvs 7059: Write VarSection;
7060: ...
1.18 cvs 7061: END;</pre>
1.30 cvs 7062:
7063: <p>(see <a href="#varsectexample">above</a> for the definition of the
7064: <tt>VarSection</tt> variable).</p>
7065:
7066: <p>To display text on the terminal before issuing a read operation with the
7067: <tt>Read</tt> rule, the following rule is used:</p>
7068: <pre>BEGIN
1.1 cvs 7069: Write 'Enter the name of the destination: ';
7070: ...
1.18 cvs 7071: END;</pre>
7072: </blockquote>
7073: </div>
7074:
7075: <div class="subsection">
1.37 cvs 7076: <h3><a name="sectc5212" id="sectc5212">The <tt>Read</tt> rule</a></h3>
1.18 cvs 7077:
1.30 cvs 7078: <p>The <tt>Read</tt> rule reads text from the terminal during the translation
7079: of the document and saves the text read in one of the buffers declared in the
1.37 cvs 7080: <tt>BUFFERS</tt> section of the schema. The buffer to be used is indicated by
7081: its name, after the <tt>READ</tt> keyword. This name can be followed, as in
1.18 cvs 7082: the <tt>Create</tt> and <tt>Write</tt> rules, by a keyword indicating if the
7083: read operation must be performed <tt>Before</tt> or <tt>After</tt> the
1.37 cvs 7084: translation of the element's content. If this keyword is absent, the read
7085: operation is done beforehand. The text is read into the buffer and remains
1.5 cvs 7086: there until a rule using the same buffer - possibly the same rule - is
1.18 cvs 7087: applied.</p>
7088: <pre> 'Read' BufferID [ Position ] ';'</pre>
1.30 cvs 7089:
1.18 cvs 7090: <blockquote class="example">
1.30 cvs 7091: <p><strong>Example:</strong></p>
7092:
7093: <p>The following set of rules tells the user that the translator is waiting
7094: for the entry of some text, reads this text into a buffer and copies the
7095: text into the translated document.</p>
7096: <pre>BEGIN
1.1 cvs 7097: Write 'Enter the name of the destination: ';
7098: Read DestName;
7099: Create DestName;
7100: ...
1.18 cvs 7101: END;</pre>
1.30 cvs 7102:
7103: <p>(see <a href="#destname">above</a> the definition of
7104: <tt>DestName</tt>).</p>
1.18 cvs 7105: </blockquote>
7106: </div>
7107:
7108: <div class="subsection">
1.37 cvs 7109: <h3><a name="sectc5213" id="sectc5213">The <tt>Include</tt> rule</a></h3>
1.18 cvs 7110:
1.30 cvs 7111: <p>The <tt>Include</tt> rule, like the <tt>Create</tt> rule, is used to
1.37 cvs 7112: produce text in the translated document. It inserts constant text which is
7113: not defined in the translation schema, but is instead taken from a file. The
7114: file's name is specified after the <tt>Include</tt> keyword, either directly
7115: as a character string between apostrophes or as the name of one of the
7116: buffers declared in the <tt>BUFFERS</tt> section of the schema. In the latter
7117: case, the buffer is assumed to contain the file's name. This can be used when
7118: the included file's name is known only at the moment of translation. This
7119: only requires that the <tt>Include</tt> rule is preceded by a <tt>Read</tt>
7120: rule which puts the name of the file desired by the user into the buffer.</p>
1.30 cvs 7121:
7122: <p>Like the other rules, it is possible to specify whether the inclusion will
1.1 cvs 7123: occur before or after the element's content, with the default being before.
7124: The file inclusion is only done at the moment of translation, not during the
7125: compilation of the translation schema. Thus, the file to be included need not
7126: exist during the compilation, but it must be accessible at the time of
1.37 cvs 7127: translation. Its contents can also be modified between two translations, thus
1.1 cvs 7128: producing different results, even if neither the document or the translation
1.18 cvs 7129: schema are modified.</p>
1.30 cvs 7130:
7131: <p>During translation, the file to be included is searched for along the
7132: schema directory path (indicated by the environment variable
1.37 cvs 7133: <tt>THOTSCH</tt>). The file name is normally only composed of a simple name,
7134: without specification of a complete file path. However, if the filename
1.30 cvs 7135: starts with a '/', it is considered as an absolute path.</p>
1.18 cvs 7136: <pre> 'Include' File [ Position ] ';'
1.6 cvs 7137: File = FileName / BufferID .
1.18 cvs 7138: FileName = STRING .</pre>
1.30 cvs 7139:
1.18 cvs 7140: <blockquote class="example">
1.30 cvs 7141: <p><strong>Example:</strong></p>
7142:
1.37 cvs 7143: <p>Suppose that it is desirable to print documents of the Article class
7144: with a formatter which requires a number of declarations and definitions at
7145: the beginning of the file. The <tt>Include</tt>rule can be used to achieve
1.30 cvs 7146: this. All the declarations and definitions a replaced in a file called
7147: <tt>DeclarArt</tt> and then the <tt>Article</tt> element type is given the
7148: following rule:</p>
7149: <pre>Article : BEGIN
1.1 cvs 7150: Include 'DeclarArt' Before;
7151: ...
1.18 cvs 7152: END;</pre>
7153: </blockquote>
7154: </div>
7155:
7156: <div class="subsection">
1.37 cvs 7157: <h3><a name="sectc5214" id="sectc5214">The <tt>Get</tt> rule</a></h3>
1.18 cvs 7158:
1.30 cvs 7159: <p>The <tt>Get</tt> rule is used to change the order in which the elements
1.37 cvs 7160: appear in the translated document. More precisely, it produces the
1.30 cvs 7161: translation of a specified element before or after the translation of the
1.37 cvs 7162: content of the element to which the rule applies. The <tt>Before</tt> and
1.30 cvs 7163: <tt>After</tt> keywords are placed at the end of the rule to specify whether
7164: the operation should be performed before or after translation of the rule's
7165: element (the default is before). The type of the element to be moved must be
7166: specified after the <tt>Get</tt> keyword, optionally preceded by a keyword
7167: indicating where the element will be found in the logical structure of the
7168: document:</p>
1.18 cvs 7169: <dl>
1.30 cvs 7170: <dt><tt>Included</tt></dt>
7171: <dd>The element to be moved is the first element of the indicated type
7172: which is found inside the element to which the rule applies.</dd>
7173: <dt><tt>Referred</tt></dt>
7174: <dd>This keyword can only be used if the rule applies to a reference
1.37 cvs 7175: element. The element to be moved is either the element designated by
7176: the reference (if that element is of the specified type), or the first
1.30 cvs 7177: element of the desired type contained within the element designated by
7178: the reference.</dd>
7179: <dt>no keyword</dt>
1.37 cvs 7180: <dd><p>The translator takes the first element of the indicated type from
7181: among the siblings of the rule's element. This is primarily used to
7182: change the order of the components of an aggregate.</p>
1.30 cvs 7183: </dd>
1.18 cvs 7184: </dl>
1.30 cvs 7185:
7186: <p>If the element to be moved is defined in a structure schema which is not
7187: the one which corresponds to the translation schema (in the case of an
7188: included object with a different schema), the type name of this element must
7189: be followed, between parentheses, by the name of the structure schema which
1.18 cvs 7190: defines it.</p>
7191: <pre> 'Get' [ RelPosition ] ElemID
1.6 cvs 7192: [ ExtStruct ]
7193: [ Position ] ';' /
7194: RelPosition = 'Included' / 'Referred' .
1.18 cvs 7195: ExtStruct = '(' ElemID ')' .</pre>
1.30 cvs 7196:
7197: <p>The <tt>Get</tt> rule has no effect if the element which it is supposed to
1.37 cvs 7198: move has already been translated. Thus, the element will not be duplicated.
1.1 cvs 7199: It is generally best to associate the rule with the first element which will
1.37 cvs 7200: be encountered by the translator in its traversal of the document. Suppose an
1.18 cvs 7201: aggregate has two elements <tt>A</tt> and <tt>B</tt>, with <tt>A</tt>
1.37 cvs 7202: appearing first in the logical structure. To permute these two elements, a
1.18 cvs 7203: <tt>Get B before</tt> rule should be associated with the <tt>A</tt> element
1.37 cvs 7204: type, not the inverse. Similarly, a rule of the form <tt>Get Included X
1.18 cvs 7205: After</tt>, even though syntactically correct, makes no sense since, by the
1.1 cvs 7206: time it will be applied, after the translation of the contents of the element
1.18 cvs 7207: to which it is attached, the <tt>X</tt> element will already have been
7208: translated.</p>
7209: </div>
7210:
7211: <div class="subsection">
1.37 cvs 7212: <h3><a name="sectc5215" id="sectc5215">The <tt>Copy</tt> rule</a></h3>
1.18 cvs 7213:
1.30 cvs 7214: <p>Like the <tt>Get</tt> rule, the <tt>Copy</tt> rule generates the
7215: translation of a specified element, but it acts even if the element has
7216: already been translated and it allows to copy it or to translate it later.
7217: Both rules have the same syntax.</p>
1.18 cvs 7218: <pre> 'Copy' [ RelPosition ] ElemID
7219: [ ExtStruct ] [ Position ] ';'</pre>
7220: </div>
7221:
7222: <div class="subsection">
1.37 cvs 7223: <h3><a name="sectc5216" id="sectc5216">The <tt>Use</tt> rule</a></h3>
1.18 cvs 7224:
1.30 cvs 7225: <p>The <tt>Use</tt> rule specifies the translation schema to be applied to
1.37 cvs 7226: objects of a certain class that are part of the document. This rule only
1.1 cvs 7227: appears in the rules for the root element of the document (the first type
1.18 cvs 7228: defined after the <tt>STRUCT</tt> keyword in the structure schema) or the
1.1 cvs 7229: rules of an element defined by an external structure (by another structure
1.37 cvs 7230: schema). Also, the <tt>Use</tt> rule cannot be conditional.</p>
1.30 cvs 7231:
7232: <p>If the rule is applied to an element defined by an external structure, the
1.18 cvs 7233: <tt>Use</tt> keyword is simply followed by the name of the translation schema
1.37 cvs 7234: to be used for element constructed according to that external structure. If
1.1 cvs 7235: the rule is applied to the document's root element, it is formed by the
1.18 cvs 7236: <tt>Use</tt> keyword followed by the translation schema's name, the
7237: <tt>For</tt> keyword and the name of the external structure to which the
7238: indicated translation schema should be applied.</p>
7239: <pre> 'Use' TrSchema [ 'For' ElemID ] ';'
7240: TrSchema = NAME .</pre>
1.30 cvs 7241:
7242: <p>If no <tt>Use</tt> rule defines the translation schema to be used for an
1.1 cvs 7243: external structure which appears in a document, the translator asks the user,
7244: during the translation process, which schema should be used. Thus, it is not
1.18 cvs 7245: necessary to give the translation schema a <tt>Use</tt> rule for every
1.1 cvs 7246: external structure used, especially when the choice of translation schemas is
1.18 cvs 7247: to be left to the user.</p>
1.30 cvs 7248:
7249: <p>Notice: if the translator is launched by the editor (by the ``Save as''
1.18 cvs 7250: command), prompts are not displayed.</p>
1.30 cvs 7251:
1.18 cvs 7252: <blockquote class="example">
1.30 cvs 7253: <p><strong>Example:</strong></p>
7254:
7255: <p>The <tt>Article</tt> structure schema uses the <tt>Formula</tt> external
7256: structure, defined by another structure schema, for mathematical
7257: formulas:</p>
7258: <pre>STRUCTURE Article;
1.1 cvs 7259: ...
7260: STRUCT
7261: Article = ...
7262: ...
7263: Formula_in_text = Formula;
7264: Isolated_formula = Formula;
7265: ...
1.18 cvs 7266: END</pre>
1.30 cvs 7267:
7268: <p>Suppose that it would be useful to use the <tt>FormulaT</tt> translation
1.37 cvs 7269: schema for the formulas of an article. This can be expressed in two
1.30 cvs 7270: different ways in the <tt>Article</tt> class translation schema, using the
7271: rules:</p>
7272: <pre>RULES
1.1 cvs 7273: Article :
1.18 cvs 7274: Use FormulaT for Formula;</pre>
1.30 cvs 7275:
7276: <p>or:</p>
7277: <pre>RULES
1.1 cvs 7278: ...
7279: Formula :
1.18 cvs 7280: Use FormulaT;</pre>
7281: </blockquote>
7282: </div>
7283:
7284: <div class="subsection">
1.37 cvs 7285: <h3><a name="sectc5217" id="sectc5217">The <tt>Remove</tt> rule</a></h3>
1.18 cvs 7286:
1.37 cvs 7287: <p>The <tt>Remove</tt> rule indicates that nothing should be generated, in
7288: the translated document, for the content of the element to which the rule
7289: applies. The content of that element is simply ignored by the translator.
7290: This does not prevent the generation of text for the element itself, using
7291: the <tt>Create</tt> or <tt>Include</tt> rules, for example.</p>
1.30 cvs 7292:
7293: <p>The <tt>Remove</tt> rule is simply written with the <tt>Remove</tt>
7294: keyword. It is terminated, like all rules, by a semicolon.</p>
1.18 cvs 7295: <pre> 'Remove' ';'</pre>
7296: </div>
7297:
7298: <div class="subsection">
1.37 cvs 7299: <h3><a name="sectc5217a" id="sectc5217a">The <tt>Ignore</tt> rule</a></h3>
1.31 cvs 7300:
1.37 cvs 7301: <p>The <tt>Ignore</tt> rule indicates that nothing should be generated, in
7302: the translated document, for the element to which the rule applies. The whole
1.32 cvs 7303: element is simply ignored by the translator.</p>
1.31 cvs 7304:
7305: <p>The <tt>Ignore</tt> rule is simply written with the <tt>Ignore</tt>
7306: keyword. It is terminated, like all rules, by a semicolon.</p>
7307: <pre> 'Ignore' ';'</pre>
7308: </div>
7309:
7310: <div class="subsection">
1.37 cvs 7311: <h3><a name="sectc5218" id="sectc5218">The <tt>NoTranslation</tt>
7312: rule</a></h3>
1.18 cvs 7313:
1.30 cvs 7314: <p>The <tt>NoTranslation</tt> rule indicates to the translator that it must
1.37 cvs 7315: not translate the content of the leaves of the element to which it applies.
7316: In contrast to the <tt>Remove</tt> rule, it does not suppress the content of
7317: the element, but it inhibits the translation of character strings, symbols,
7318: and graphical elements contained in the element. These are retrieved so that
1.18 cvs 7319: after the translation of the document, the rules of the <a
7320: href="#sectc5225"><tt>TEXTTRANSLATE</tt>, <tt>SYMBTRANSLATE</tt> and
7321: <tt>GRAPHTRANSLATE</tt> sections</a> will not be applied to them.</p>
1.30 cvs 7322:
7323: <p>The <tt>NoTranslation</tt> rule is written with the <tt>NoTranslation</tt>
1.18 cvs 7324: keyword followed by a semicolon.</p>
7325: <pre> 'NoTranslation' ';'</pre>
7326: </div>
7327:
7328: <div class="subsection">
1.37 cvs 7329: <h3><a name="sectc5219" id="sectc5219">The <tt>NoLineBreak</tt> rule</a></h3>
1.18 cvs 7330:
1.30 cvs 7331: <p>The <tt>NoLineBreak</tt> rule indicates to the translator that it must not
1.1 cvs 7332: generate additional line breaks in the output produced for the element to
1.37 cvs 7333: which it applies. This is as if it was an <a href="#sectc522">instruction
1.18 cvs 7334: <tt>LINELENGTH 0;</tt></a> at the beginning of the translation schema, but
7335: only for the current element.</p>
1.30 cvs 7336:
7337: <p>The <tt>NoLineBreak</tt> rule is written with the <tt>NoLineBreak</tt>
7338: keyword followed by a semicolon.</p>
1.18 cvs 7339: <pre> 'NoLineBreak' ';'</pre>
7340: </div>
1.1 cvs 7341:
1.18 cvs 7342: <div class="subsection">
1.37 cvs 7343: <h3><a name="sectc5220" id="sectc5220">The <tt>ChangeMainFile</tt>
7344: rule</a></h3>
1.1 cvs 7345:
1.30 cvs 7346: <p>When the translation program starts, it opens a main output file, whose
1.37 cvs 7347: name is given as a parameter of the translator. All <a
7348: href="#sectc5210"><tt>Create</tt> rules</a> without explicit indication of
7349: the output file write sequentially in this file. When a
7350: <tt>ChangeMainFile</tt> rule is executed, the main output file is closed and
7351: it is replaced by a new one, whose name is specified in the
7352: <tt>ChangeMainFile</tt> rule. The <tt>Create</tt> rules without indication of
7353: the output file that are then executed write in this new file. Several
7354: <tt>ChangeMainFile</tt> rules can be executed during the same translation,
7355: for dividing the main output into several files.</p>
1.30 cvs 7356:
7357: <p>This rule is written with the <tt>ChangeMainFile</tt> keyword followed by
7358: the name of a variable that specifies the name of the new main file. The
1.37 cvs 7359: keyword <tt>Before</tt> or <tt>After</tt> can be placed at the end of the
7360: rule to specify whether the operation should be performed before or after
7361: translation of the rule's element (the default is before). This rule, like
7362: all translation rules, is terminated by a semicolon.</p>
1.18 cvs 7363: <pre> 'ChangeMainFile' VarID [ Position ] ';'</pre>
1.30 cvs 7364:
1.18 cvs 7365: <blockquote class="example">
1.30 cvs 7366: <p><strong>Example:</strong></p>
7367:
7368: <p>To generate the translation of each section in a different file, the
1.37 cvs 7369: following rule can be associated with type <tt>Section</tt>. That rule uses
1.30 cvs 7370: the <a href="#varoutputfile"><tt>VarOutpuFile</tt> variable</a> defined
7371: above.</p>
7372: <pre> Section:
1.18 cvs 7373: ChangeMainFile VarOutpuFile Before;</pre>
1.30 cvs 7374:
7375: <p>If <tt>output.txt</tt> is the name of the output file specified when
7376: starting the translation program, translated sections are written in files
7377: <tt>output1.txt</tt>, <tt>output2.txt</tt>, etc.</p>
1.18 cvs 7378: </blockquote>
7379: </div>
1.1 cvs 7380:
1.18 cvs 7381: <div class="subsection">
1.37 cvs 7382: <h3><a name="sectc5220a" id="sectc5220a">The <tt>RemoveFile</tt> rule</a></h3>
1.14 cvs 7383:
1.37 cvs 7384: <p>Files may be used for storing temporary data that are no longer needed
7385: when the translation of a document is complete. These files may be removed by
7386: the <tt>RemoveFile</tt> rule.</p>
1.30 cvs 7387:
7388: <p>This rule is written with the <tt>RemoveFile</tt> keyword followed by the
1.37 cvs 7389: name of a variable that specifies the name of the file to be removed. The
7390: keyword <tt>Before</tt> or <tt>After</tt> can be placed at the end of the
7391: rule to specify whether the operation should be performed before or after
7392: translation of the rule's element (the default is before). This rule, like
1.30 cvs 7393: all translation rules, is terminated by a semicolon.</p>
1.18 cvs 7394: <pre> 'RemoveFile' VarID [ Position ] ';'</pre>
7395: </div>
7396:
7397: <div class="subsection">
1.37 cvs 7398: <h3><a name="sectc5221" id="sectc5221">The <tt>Set</tt> and <tt>Add</tt>
7399: rules</a></h3>
1.18 cvs 7400:
1.37 cvs 7401: <p>The <tt>Set</tt> and <tt>Add</tt> rules are used for modifying the value
7402: of counters that have no <a href="#sectc524">counting function</a>. Only this
1.18 cvs 7403: type of counter can be used in the <tt>Set</tt> and <tt>Add</tt> rules.</p>
1.30 cvs 7404:
7405: <p>Both rules have the same syntax: after the keyword <tt>Set</tt> or
1.18 cvs 7406: <tt>Add</tt> appear the counter name and the value to assign to the counter
7407: (<tt>Set</tt> rule) or the value to be added to the counter (<tt>Add</tt>
1.37 cvs 7408: rule). The keyword <tt>Before</tt> or <tt>After</tt> can follow that value to
1.1 cvs 7409: indicate when the rule must be applied: before or after the element's content
1.37 cvs 7410: is translated. By default, <tt>Before</tt> is assumed. A semicolon terminates
1.18 cvs 7411: the rule.</p>
7412: <pre> 'Set' CounterID InitValue [ Position ] ';' /
7413: 'Add' CounterID Increment [ Position ] ';'</pre>
7414: </div>
7415:
7416: <div class="subsection">
1.37 cvs 7417: <h3><a name="sectc5221a" id="sectc5221a">The <tt>Indent</tt> rule</a></h3>
1.18 cvs 7418:
1.37 cvs 7419: <p>The <tt>Indent</tt> rule is used to modify the value of text indentation
7420: in the output files.</p>
1.30 cvs 7421:
1.37 cvs 7422: <p>Each time the translator creates a new line in an output file, it
7423: generates a variable number of space characters at the beginning of the new
7424: line. By default, the number of these characters (the indentation value) is
7425: 0. It can be changed with the <tt>Indent</tt> rule.</p>
1.30 cvs 7426:
7427: <p>In its simple form, the rule begins with the <tt>Indent</tt> keyword,
1.25 cvs 7428: followed by the indentation sign (optional) and value and a keyword
1.30 cvs 7429: <tt>Before</tt> or <tt>After</tt> indicating that the indentation should be
7430: changed <a href="#sectc5222">before or after</a> the element's content is
1.37 cvs 7431: generated. If the position is not indicated, the indentation is changed
7432: before the element's content is generated. This rule, like all translation
1.25 cvs 7433: rules, is terminated by a semicolon.</p>
1.30 cvs 7434:
7435: <p>The indentation value is indicated by an integer, which is the number of
7436: space characters to be generated at the beginning of each new line. A sign
1.18 cvs 7437: (<tt>+</tt> or <tt>-</tt>) can appear before the integer to indicate that the
1.37 cvs 7438: value is relative: the current value of indentation is incremented (if sign
7439: is <tt>+</tt>) or decremented (if sign is <tt>-</tt>) by the specified
7440: value.</p>
1.30 cvs 7441:
7442: <p>Keyword <tt>Suspend</tt> or <tt>Resume</tt> can appear instead of the
1.37 cvs 7443: (possibly signed) identation value. <tt>Suspend</tt> means that the new
1.30 cvs 7444: indentation value to be used is zero until another <tt>Indent</tt> rule is
7445: executed and changes the indentation value. <tt>Resume</tt> means that the
7446: indentation value that was used before the last <tt>Indent Suspend</tt> was
1.37 cvs 7447: executed becomes the new value. Only one <tt>Suspend</tt> can be used before
1.30 cvs 7448: a <tt>Resume</tt>; <tt>Supend</tt>-<tt>Resume</tt> pairs can not be
7449: nested.</p>
7450:
1.37 cvs 7451: <p>Like the <a href="#sectc5210"><tt>Create</tt> rule</a>, the
7452: <tt>Indent</tt> keyword can be followed by the <tt>IN</tt> keyword and by the
7453: name of a <a href="#sectc526">variable</a>. This means that the rule must not
7454: change indentation in the main output file, but in the file whose name is
7455: specified by the variable (by default, indentation is changed in the main
7456: output file).</p>
1.25 cvs 7457: <pre> 'Indent' [ 'IN' VarID ] Indent [ Position ] ';' .
1.10 cvs 7458:
1.25 cvs 7459: Indent = 'Suspend' / 'Resume' / [ IndentSign ] IndentValue .
1.10 cvs 7460: IndentSign = '+' / '-' .
1.18 cvs 7461: IndentValue = NUMBER .</pre>
7462: </div>
1.10 cvs 7463:
1.18 cvs 7464: <div class="subsection">
1.37 cvs 7465: <h3><a name="sectc5222" id="sectc5222">Rule application order</a></h3>
1.1 cvs 7466:
1.30 cvs 7467: <p>The translator translates the elements which comprise the document in the
1.37 cvs 7468: order induced by the tree structure, except when the <tt>Get</tt> rule is
7469: used to change the order of translation. For each element, the translator
7470: first applies the rules specified for the element's type that must be applied
7471: before translation of the element's content (rules ending with the
7472: <tt>Before</tt> keyword or which have no position keyword). If several rules
7473: meet these criteria, the translator applies them in the order in where they
7474: appear in the translation schema.</p>
7475:
7476: <p>It then applies all <a href="#sectc5223">rules for the attributes</a>
7477: which the element has and which must be applied before the translation of the
7478: element's content (rules ending with the <tt>Before</tt> keyword or which
7479: have no position keyword). For one attribute value, the translator applies
7480: the rules in the order in which they are defined in the translation
7481: schema.</p>
1.30 cvs 7482:
7483: <p>The same procedure is followed with translation rules for specific
1.18 cvs 7484: presentations.</p>
1.30 cvs 7485:
1.31 cvs 7486: <p>Next, the element's content is translated, as long as a <tt>Remove</tt> or
7487: <code>Ignore</code> rule does not apply.</p>
1.30 cvs 7488:
7489: <p>In the next step, the translator applies rules for the specific
7490: presentation of the element that are to be applied after translation of the
1.37 cvs 7491: content (rules which end with the <tt>After</tt> keyword). The rules for each
1.30 cvs 7492: type of presentation rule or each value are applied in the order in which the
1.18 cvs 7493: translation appear in the schema.</p>
1.30 cvs 7494:
7495: <p>Then, the same procedure is followed for translation rules for attributes
7496: of the element.</p>
7497:
1.37 cvs 7498: <p>Finally, the translator applies rules for the element which must be
7499: applied after translation of the element's content. These rules are applied
7500: in the order that they appear in the translation schema. When the translation
7501: of an element is done, the translator procedes to translate the following
1.18 cvs 7502: element.</p>
1.30 cvs 7503:
7504: <p>This order can be changed with the <tt>Attributes</tt> and
1.18 cvs 7505: <tt>Presentation</tt> options of the <a href="#sectc5210"><tt>Create</tt>
7506: rule</a>.</p>
7507: </div>
1.1 cvs 7508:
1.18 cvs 7509: <div class="subsection">
1.37 cvs 7510: <h3><a name="sectc5223" id="sectc5223">Translation of logical
7511: attributes</a></h3>
1.1 cvs 7512:
1.37 cvs 7513: <p>After the rules for the element types, the translation schema defines
7514: rules for attribute values. This section begins with the <tt>ATTRIBUTES</tt>
1.1 cvs 7515: keyword and is composed of a sequence of rule blocks each preceded by an
1.18 cvs 7516: attribute name and an optional value or value range.</p>
1.30 cvs 7517:
7518: <p>If the attribute's name appears alone before the rule block, the rule are
1.1 cvs 7519: applied to all element which have the attribute, no matter what value the
1.37 cvs 7520: attribute has. In this case, the attribute name is followed by a colon before
1.18 cvs 7521: the beginning of the rule block.</p>
1.30 cvs 7522:
1.37 cvs 7523: <p>The attribute's name can be followed by the name of an element type
7524: between parentheses. This says, as in presentation schemas, that the rule
7525: block which follows applies not to the element which has the attribute, but
7526: to its descendants of the type indicated between the parentheses.</p>
1.30 cvs 7527:
7528: <p>If values are given after the attribute name (or after the name of the
1.37 cvs 7529: element type), the rules are applied only when the attribute has the
7530: indicated values. The same attribute can appear several times, with different
7531: values and different translation rules. Attribute values are indicated in the
7532: same way as in <a href="#sectc528">conditions</a> and are followed by a colon
7533: before the block of rules.</p>
1.30 cvs 7534:
7535: <p>The rule block associated with an attribute is either a simple rule or a
1.18 cvs 7536: sequence of rules delimited by the <tt>BEGIN</tt> and <tt>END</tt> keywords.
7537: Note that rules associated with attribute values cannot be conditional.</p>
1.30 cvs 7538:
7539: <p>Translation rules are not required for all attributes (or their values)
1.37 cvs 7540: defined in a structure schema. Only those attributes for which a particular
7541: action must be performed by the translator must have such rules. The rules
1.18 cvs 7542: that can be used are those described above, from <a
7543: href="#sectc5210"><tt>Create</tt></a> to <a
7544: href="#sectc5218"><tt>NoTranslation</tt></a>.</p>
1.30 cvs 7545: <pre> AttrSeq = TransAttr < TransAttr > .
1.1 cvs 7546: TransAttr = AttrID [ '(' ElemID ')' ]
7547: [ RelatAttr ] ':' RuleSeq .
7548: AttrID = NAME .
1.18 cvs 7549: ElemID = NAME .</pre>
1.30 cvs 7550:
1.18 cvs 7551: <blockquote class="example">
1.30 cvs 7552: <p><strong>Example:</strong></p>
7553:
7554: <p>The structure defined the ``Language'' attribute which can take the
1.37 cvs 7555: values ``French'' and ``English''. To have the French parts of the original
1.30 cvs 7556: document removed and prevent the translation of the leaves of the English
7557: parts, the following rules would be used:</p>
7558: <pre>ATTRIBUTES
1.1 cvs 7559: Language=French :
7560: Remove;
7561: Language=English :
1.18 cvs 7562: NoTranslation;</pre>
7563: </blockquote>
7564: </div>
1.1 cvs 7565:
1.18 cvs 7566: <div class="subsection">
1.37 cvs 7567: <h3><a name="sectc5224" id="sectc5224">Translation of specific
7568: presentations</a></h3>
1.1 cvs 7569:
1.30 cvs 7570: <p>After the rules for attributes, the translation schema defines rules for
1.37 cvs 7571: the specific presentation. This section begins with the <tt>PRESENTATION</tt>
7572: keyword and is composed of a sequence of translation rule blocks each
7573: preceded by a presentation rule name, optionally accompanied by a part which
7574: depends on the particular presentation rule.</p>
1.30 cvs 7575:
7576: <p>Each of these translation rule blocks is applied when the translator
7577: operates on an element which has a specific presentation rule of the type
1.37 cvs 7578: indicated at the head of the block. Depending on the type of the specific
1.30 cvs 7579: presentation rule, it is possible to specify values of the presentation rule
7580: for which the translation rule block should be applied.</p>
7581:
7582: <p>There are three categories of the presentation rules:</p>
7583: <ul>
7584: <li>rules taking numeric values: <tt>Size</tt>, <tt>Indent</tt>,
7585: <tt>LineSpacing</tt>, <tt>LineWeight</tt>,</li>
7586: <li>rules whose values are taken from a predefined list (i.e. whose type is
1.43 quint 7587: an enumeration): <tt>Adjust</tt>, <tt>Hyphenate,Direction, UnicodeBidi,
1.40 quint 7588: <tt>Style</tt>, <tt>Weight</tt>, <tt>Font</tt>, <tt>UnderLine</tt>,
7589: <tt>Thickness</tt>, <tt>LineStyle</tt>,</tt></li>
1.30 cvs 7590: <li>rules whose value is a name: <tt>FillPattern</tt>, <tt>Background</tt>,
7591: <tt>Foreground</tt>.</li>
1.18 cvs 7592: </ul>
1.30 cvs 7593:
7594: <p>For presentation rules of the first category, the values which provoke
1.1 cvs 7595: application of the translation rules are indicated in the same manner as for
1.37 cvs 7596: <a href="#relattr">numeric attributes</a>. This can be either a unique value
7597: or range of values. For a unique value, the value (an integer) is simply
7598: preceded by an equals sign. Value ranges can be specified in one of three
1.18 cvs 7599: ways:</p>
7600: <ul>
1.30 cvs 7601: <li>all values less than a given value (this value is preceded by a ``less
7602: than'' sign '<tt><</tt>'),</li>
7603: <li>all values greater than a given value (this value is preceded by a`
7604: `greater than'' sign '<tt>></tt>'),</li>
1.37 cvs 7605: <li>all values falling in an interval, bounds included. The range of values
1.30 cvs 7606: is then specified <tt>IN [</tt>Minimum<tt>..</tt>Maximum<tt>]</tt>, where
7607: Minimum and Maximum are integers.</li>
1.18 cvs 7608: </ul>
1.30 cvs 7609:
7610: <p>All numeric values can be negative, in which case the integer is preceded
1.37 cvs 7611: by a minus sign. All values must be given in typographers points.</p>
1.30 cvs 7612:
7613: <p>For presentation rules whose values are taken from a predefined list, the
1.1 cvs 7614: value which provokes application of the translation rules is simply indicated
1.18 cvs 7615: by the equals sign followed by the name of the value.</p>
1.30 cvs 7616:
1.37 cvs 7617: <p>For presentation rules whose values are names, the value which provokes
7618: the application of translation rules is simply indicated by the equals sign
7619: followed by the name of the value. The names of the fill patterns (the
1.18 cvs 7620: <tt>FillPattern</tt> rule) and of the colors (the <tt>Foreground</tt> and
7621: <tt>Background</tt> rules) used in Thot are the same as in the P language.</p>
1.30 cvs 7622: <pre> PresSeq = PresTrans < PresTrans > .
1.1 cvs 7623: PresTrans = PresRule ':' RuleSeq .
7624: PresRule = 'Size' [ PresRelation ] /
7625: 'Indent' [ PresRelation ] /
7626: 'LineSpacing' [ PresRelation ] /
7627: 'Adjust' [ '=' AdjustVal ] /
7628: 'Hyphenate' [ '=' BoolVal ] /
7629: 'Style' [ '=' StyleVal ] /
1.24 cvs 7630: 'Weight' [ '=' WeightVal ] /
1.1 cvs 7631: 'Font' [ '=' FontVal ] /
7632: 'UnderLine' [ '=' UnderLineVal ] /
7633: 'Thickness' [ '=' ThicknessVal ] /
7634: 'LineStyle' [ '=' LineStyleVal ] /
7635: 'LineWeight' [ PresRelation ] /
7636: 'FillPattern' [ '=' Pattern ] /
7637: 'Background' [ '=' Color ] /
7638: 'Foreground' [ '=' Color ] .
7639:
7640: PresRelation = '=' PresValue /
1.30 cvs 7641: '>' [ '-' ] PresMinimum /
1.1 cvs 7642: '<' [ '-' ] PresMaximum /
7643: 'IN' '[' [ '-' ] PresIntervalMin '..'
7644: [ '-' ] PresIntervalMax ']' .
1.35 cvs 7645: AdjustVal = 'Left' / 'Right' / 'VMiddle' / 'Justify' /
1.1 cvs 7646: 'LeftWithDots' .
7647: BoolVal = 'Yes' / 'No' .
1.24 cvs 7648: StyleVal = 'Roman' / 'Italics' / 'Oblique' .
7649: WeightVal = 'Normal' / 'Bold' .
1.1 cvs 7650: FontVal = 'Times' / 'Helvetica' / 'Courier' .
7651: UnderLineVal = 'NoUnderline' / 'UnderLined' /
7652: 'OverLined' / 'CrossedOut' .
7653: ThicknessVal = 'Thick' / 'Thin' .
1.6 cvs 7654: LineStyleVal = 'Solid' / 'Dashed' / 'Dotted' .
1.1 cvs 7655: Pattern = NAME .
7656: Color = NAME .
7657: PresMinimum = NUMBER .
7658: PresMaximum = NUMBER .
7659: PresIntervalMin= NUMBER .
7660: PresIntervalMax= NUMBER .
7661: PresValue = [ '-' ] PresVal .
1.18 cvs 7662: PresVal = NUMBER .</pre>
1.30 cvs 7663:
1.37 cvs 7664: <p>The <a name="prestransl" id="prestransl">translation rules associated with
7665: specific presentation rules</a> can use the value of the specific
7666: presentation rule that causes them to be applied. This behavior is designated
7667: by the keyword <tt>Value</tt>. For numerically-valued presentation rules, the
7668: numeric value is produced. For other presentation rules, the name of the
7669: value is produced.</p>
1.30 cvs 7670:
7671: <p>It should be noted that modifications to the layout of the document's
7672: elements that are made using the combination of the control key and a mouse
7673: button will have no effect on the translation of the document.</p>
7674:
7675: <blockquote class="example">
7676: <p><strong>Example:</strong></p>
7677:
7678: <p>Suppose that it is desirable to use the same font sizes as in the
7679: specific presentation, but the font size must be between 10 and 18
7680: typographer's points. If font size is set in the translated document by the
7681: string <tt>pointsize=n</tt> where <tt>n</tt> is the font size in
7682: typographer's points then the following rules will suffice:</p>
7683: <pre>PRESENTATION
1.1 cvs 7684: Size < 10 :
7685: Create 'pointsize=10';
7686: Size in [10..18] :
7687: BEGIN
7688: Create 'pointsize=';
7689: Create Value;
7690: END;
1.30 cvs 7691: Size > 18 :
1.18 cvs 7692: Create 'pointsize=18';</pre>
7693: </blockquote>
7694: </div>
1.1 cvs 7695:
1.18 cvs 7696: <div class="subsection">
1.37 cvs 7697: <h3><a name="sectc5225" id="sectc5225">Recoding of characters, symbols and
7698: graphics</a></h3>
1.1 cvs 7699:
1.37 cvs 7700: <p>The coding of characters, graphical elements and symbols as defined in
7701: Thot does not necessarily correspond to what is required by an application to
7702: which a Thot document must be exported. Because of this the translator can
7703: recode these terminal elements of the documents structure. The last sections
7704: of a translation schema are intended for this purpose, each specifying the
7705: recoding rules for one type of terminal element.</p>
1.30 cvs 7706:
1.43 quint 7707: <p>The recoding rules for character strings are grouped by scripts. There is
7708: a group of rules for each script of the Thot document that must be
1.30 cvs 7709: translated. Each such group of rules begins with the <tt>TEXTTRANSLATE</tt>
1.41 vatton 7710: keyword, followed by the specification of the script to translate and the
1.30 cvs 7711: recoding rules, between the <tt>BEGIN</tt> and <tt>END</tt> keywords unless
1.41 vatton 7712: there is only one recoding rule for the script. The specification of the
1.43 quint 7713: script is not required: by default it is assumed to the Latin script (the ISO
7714: Latin-1 character set).</p>
1.30 cvs 7715:
7716: <p>Each recoding rule is formed by a source string between apostrophes and a
1.1 cvs 7717: target string, also between apostrophes, the two strings being separated by
1.30 cvs 7718: the arrow symbol (<tt>-></tt>), formed by the ``minus'' and ``greater
1.37 cvs 7719: than'' characters. The rule is terminated by a semi-colon.</p>
1.41 vatton 7720: <pre> TextTransSeq = [ Script ] TransSeq .
7721: Script = NAME .
1.30 cvs 7722: TransSeq ='BEGIN' < Translation > 'END' ';' /
1.1 cvs 7723: Translation .
1.30 cvs 7724: Translation = Source [ '->' Target ] ';' .
1.1 cvs 7725: Source = STRING .
1.18 cvs 7726: Target = STRING .</pre>
1.30 cvs 7727:
7728: <p>One such rule signifies that when the source string appears in a text leaf
7729: of the document being translated, the translator must replace it, in the
1.37 cvs 7730: translated document, with the target string. The source string and the target
7731: string can have different lengths and the target string can be empty. In this
1.1 cvs 7732: last case, the translator simply suppresses every occurrence of the source
1.18 cvs 7733: string in the translated document.</p>
1.30 cvs 7734:
1.41 vatton 7735: <p>For a given script, the order of the rules is not important and has no
1.1 cvs 7736: significance because the T language compiler reorders the rules in ways that
1.37 cvs 7737: speed up the translator's work. The total number of recoding rules is limited
1.18 cvs 7738: by the compiler as is the maximum length of the source and target strings.</p>
1.30 cvs 7739:
7740: <p>The recoding rules for symbols and graphical elements are written in the
1.37 cvs 7741: same manner as the recoding rules for character strings. They are preceded,
7742: respectively, by the <tt>SYMBTRANSLATE</tt> and <tt>GRAPHTRANSLATE</tt> and
1.43 quint 7743: so not require a specification of the script. Their source string is limited
7744: to one character, since, in Thot, each symbol and each graphical element is
7745: represented by a single character. The symbol and graphical element codes are
7746: defined along with the <a href="#sect7">non-standard character codes</a>.</p>
1.30 cvs 7747:
1.18 cvs 7748: <blockquote class="example">
1.30 cvs 7749: <p><strong>Example:</strong></p>
7750:
7751: <p>In a translation schema producing documents destined for use with the
7752: L<sup>A</sup>T<sub><big>E</big></sub>X formatter, the Latin characters``é''
1.37 cvs 7753: (octal code 351 in Thot) and ``č'' (octal code 350 in Thot) must be
1.30 cvs 7754: converted to their representation in
7755: L<sup>A</sup>T<sub><big>E</big></sub>X:</p>
7756: <pre>TEXTTRANSLATE Latin
1.1 cvs 7757: BEGIN
1.30 cvs 7758: '\350' -> '\`{e}'; { e grave }
7759: '\351' -> '\''{e}'; { e acute }
1.18 cvs 7760: END;</pre>
7761: </blockquote>
7762: </div>
7763: </div>
1.37 cvs 7764: <hr />
1.18 cvs 7765: </div>
1.1 cvs 7766:
1.18 cvs 7767: <div class="chapter">
1.37 cvs 7768: <h1><a name="sect6" id="sect6">Language grammars</a></h1>
1.1 cvs 7769:
1.30 cvs 7770: <p>This chapter gives the complete grammars of the languages of Thot. The
1.1 cvs 7771: grammars were presented and described in the preceding chapters, which also
1.37 cvs 7772: specify the semantics of the languages. This section gives only the
1.18 cvs 7773: syntax.</p>
1.1 cvs 7774:
1.18 cvs 7775: <div class="section">
1.37 cvs 7776: <h2><a name="sectb61" id="sectb61">The M meta-language</a></h2>
1.1 cvs 7777:
1.30 cvs 7778: <p>The language grammars are all expressed in the same formalism, the M
1.18 cvs 7779: meta-language, which is defined in this section.</p>
7780: <pre>{ Any text between braces is a comment. }
1.30 cvs 7781: Grammar = Rule < Rule > 'END' .
7782: { The < and > signs indicate zero }
1.1 cvs 7783: { or more repetitions. }
7784: { END marks the end of the grammar. }
7785: Rule = Ident '=' RightPart '.' .
7786: { The period indicates the end of a rule }
7787: RightPart = RtTerminal / RtIntermed .
7788: { The slash indicates a choice }
7789: RtTerminal ='NAME' / 'STRING' / 'NUMBER' .
7790: { Right part of a terminal rule }
1.30 cvs 7791: RtIntermed = Possibility < '/' Possibility > .
1.1 cvs 7792: { Right part of an intermediate rule }
1.30 cvs 7793: Possibility = ElemOpt < ElemOpt > .
7794: ElemOpt = Element / '[' Element < Element > ']' /
7795: '<' Element < Element > '>' .
1.1 cvs 7796: { Brackets delimit optional parts }
7797: Element = Ident / KeyWord .
7798: Ident = NAME .
7799: { Identifier, sequence of characters
7800: KeyWord = STRING .
7801: { Character string delimited by apostrophes }
1.18 cvs 7802: END</pre>
7803: </div>
1.1 cvs 7804:
1.18 cvs 7805: <div class="section">
1.37 cvs 7806: <h2><a name="sectb62" id="sectb62">The S language</a></h2>
1.1 cvs 7807:
1.30 cvs 7808: <p>The S language is used to write structure schemas, which contain the
1.37 cvs 7809: generic logical structures of document and object classes. It is described
1.30 cvs 7810: here in the M meta-language.</p>
1.18 cvs 7811: <pre>StructSchema = 'STRUCTURE' [ 'EXTENSION' ] ElemID ';'
1.1 cvs 7812: 'DEFPRES' PresID ';'
7813: [ 'ATTR' AttrSeq ]
7814: [ 'STRUCT' RulesSeq ]
7815: [ 'EXTENS' ExtensRuleSeq ]
7816: [ 'UNITS' RulesSeq ]
7817: [ 'EXPORT' SkeletonSeq ]
7818: [ 'EXCEPT' ExceptSeq ]
7819: 'END' .
7820:
7821: ElemID = NAME .
7822: PresID = NAME .
7823:
1.30 cvs 7824: AttrSeq = Attribute < Attribute > .
1.1 cvs 7825: Attribute = AttrID '=' AttrType ';' .
7826: AttrType = 'INTEGER' / 'TEXT' /
7827: 'REFERENCE' '(' RefType ')' /
7828: ValueSeq .
7829: RefType = 'ANY' /
7830: [ FirstSec ] ElemID [ ExtStruct ] .
1.30 cvs 7831: ValueSeq = AttrVal < ',' AttrVal > .
1.1 cvs 7832: AttrID = NAME .
7833: FirstSec = 'First' / 'Second' .
7834: ExtStruct = '(' ElemID ')' .
7835: AttrVal = NAME .
7836:
1.30 cvs 7837: RulesSeq = Rule < Rule > .
1.1 cvs 7838: Rule = ElemID [ LocAttrSeq ] '='
7839: DefWithAttr ';' .
7840: LocAttrSeq = '(' 'ATTR' LocalAttr
1.30 cvs 7841: < ';' LocalAttr > ')' .
1.1 cvs 7842: LocalAttr = [ '!' ] AttrID [ '=' AttrType ] .
7843: DefWithAttr = Definition
7844: [ '+' '(' ExtensionSeq ')' ]
7845: [ '-' '(' RestrictSeq ')' ]
7846: [ 'WITH' FixedAttrSeq ] .
1.30 cvs 7847: ExtensionSeq = ExtensionElem < ',' ExtensionElem > .
1.1 cvs 7848: ExtensionElem = ElemID / 'TEXT' / 'GRAPHICS' /
7849: 'SYMBOL' / 'PICTURE' .
1.30 cvs 7850: RestrictSeq = RestrictElem < ',' RestrictElem > .
1.1 cvs 7851: RestrictElem = ElemID / 'TEXT' / 'GRAPHICS' /
7852: 'SYMBOL' / 'PICTURE' .
1.30 cvs 7853: FixedAttrSeq = FixedAttr < ',' FixedAttr > .
1.1 cvs 7854: FixedAttr = AttrID [ FixedOrModifVal ] .
7855: FixedOrModifVal= [ '?' ] '=' FixedValue .
7856: FixedValue = [ '-' ] NumValue / TextValue / AttrVal .
7857: NumValue = NUMBER .
7858: TextValue = STRING .
7859:
7860: Definition = BaseType [ LocAttrSeq ] / Constr /
7861: Element .
7862: BaseType = 'TEXT' / 'GRAPHICS' / 'SYMBOL' /
7863: 'PICTURE' / 'UNIT' / 'NATURE' .
7864: Element = ElemID [ ExtOrDef ] .
7865: ExtOrDef = 'EXTERN' / 'INCLUDED' /
7866: [ LocAttrSeq ] '=' Definition .
7867:
7868: Constr = 'LIST' [ '[' min '..' max ']' ] 'OF'
7869: '(' DefWithAttr ')' /
7870: 'BEGIN' DefOptSeq 'END' /
7871: 'AGGREGATE' DefOptSeq 'END' /
7872: 'CASE' 'OF' DefSeq 'END' /
7873: 'REFERENCE' '(' RefType ')' /
7874: 'PAIR' .
7875:
7876: min = Integer / '*' .
7877: max = Integer / '*' .
7878: Integer = NUMBER .
7879:
1.30 cvs 7880: DefOptSeq = DefOpt ';' < DefOpt ';' > .
1.1 cvs 7881: DefOpt = [ '?' ] DefWithAttr .
7882:
1.30 cvs 7883: DefSeq = DefWithAttr ';' < DefWithAttr ';' > .
1.1 cvs 7884:
1.30 cvs 7885: SkeletonSeq = SkeletonElem < ',' SkeletonElem > ';' .
1.1 cvs 7886: SkeletonElem = ElemID [ 'WITH' Contents ] .
7887: Contents = 'Nothing' / ElemID [ ExtStruct ] .
7888:
1.30 cvs 7889: ExceptSeq = Except ';' < Except ';' > .
1.1 cvs 7890: Except = [ 'EXTERN' ] [ FirstSec ] ExcTypeOrAttr ':'
7891: ExcValSeq .
7892: ExcTypeOrAttr = ElemID / AttrID .
1.30 cvs 7893: ExcValSeq = ExcValue < ',' ExcValue > .
1.1 cvs 7894: ExcValue = 'NoCut' / 'NoCreate' /
7895: 'NoHMove' / 'NoVMove' / 'NoMove' /
7896: 'NoHResize' / 'NoVResize' / 'NoResize' /
1.18 cvs 7897: 'MoveResize' /
1.1 cvs 7898: 'NewWidth' / 'NewHeight' /
7899: 'NewHPos' / 'NewVPos' /
7900: 'Invisible' / 'NoSelect' /
7901: 'Hidden' / 'ActiveRef' /
7902: 'ImportLine' / 'ImportParagraph' /
1.9 cvs 7903: 'NoPaginate' / 'ParagraphBreak' /
7904: 'HighlightChildren' / 'ExtendedSelection' /
1.36 cvs 7905: 'SelectParent' / 'ClickableSurface' /
1.29 cvs 7906: 'ReturnCreateNL' / 'ReturnCreateWithin' .
1.1 cvs 7907:
1.30 cvs 7908: ExtensRuleSeq = ExtensRule ';' < ExtensRule ';' > .
1.1 cvs 7909: ExtensRule = RootOrElem [ LocAttrSeq ]
7910: [ '+' '(' ExtensionSeq ')' ]
7911: [ '-' '(' RestrictSeq ')' ]
7912: [ 'WITH' FixedAttrSeq ] .
7913: RootOrElem = 'Root' / ElemID .
7914:
1.18 cvs 7915: END</pre>
7916: </div>
1.1 cvs 7917:
1.18 cvs 7918: <div class="section">
1.37 cvs 7919: <h2><a name="sectb63" id="sectb63">The P language</a></h2>
1.1 cvs 7920:
1.30 cvs 7921: <p>The P language is used to write presentation schemas, which define the
1.1 cvs 7922: graphical presentation rules to be applied to different classes of documents
1.37 cvs 7923: and objects. It is described here in the M meta-language.</p>
1.18 cvs 7924: <pre>PresSchema = 'PRESENTATION' ElemID ';'
1.1 cvs 7925: [ 'VIEWS' ViewSeq ]
7926: [ 'PRINT' PrintViewSeq ]
7927: [ 'COUNTERS' CounterSeq ]
7928: [ 'CONST' ConstSeq ]
7929: [ 'VAR' VarSeq ]
7930: [ 'DEFAULT' ViewRuleSeq ]
7931: [ 'BOXES' BoxSeq ]
7932: [ 'RULES' PresentSeq ]
7933: [ 'ATTRIBUTES' PresAttrSeq ]
7934: [ 'TRANSMIT' TransmitSeq ]
7935: 'END' .
7936:
7937: ElemID = NAME .
7938:
7939: ViewSeq = ViewDeclaration
1.30 cvs 7940: < ',' ViewDeclaration > ';' .
1.1 cvs 7941: ViewDeclaration = ViewID [ 'EXPORT' ] .
7942: ViewID = NAME .
7943:
1.30 cvs 7944: PrintViewSeq = PrintView < ',' PrintView > ';' .
1.37 cvs 7945: PrintView = ViewID .
1.1 cvs 7946:
1.30 cvs 7947: CounterSeq = Counter < Counter > .
1.1 cvs 7948: Counter = CounterID ':' CounterFunc ';' .
7949: CounterID = NAME .
7950: CounterFunc = 'RANK' 'OF' TypeOrPage [ SLevelAsc ]
7951: [ 'INIT' AttrID ] [ 'REINIT' AttrID ] /
1.30 cvs 7952: SetFunction < SetFunction >
7953: AddFunction < AddFunction >
1.1 cvs 7954: [ 'INIT' AttrID ] /
1.16 cvs 7955: 'RLEVEL' 'OF' ElemID .
1.1 cvs 7956: SLevelAsc = [ '-' ] LevelAsc .
7957: LevelAsc = NUMBER .
7958: SetFunction = 'SET' CounterValue 'ON' TypeOrPage .
7959: AddFunction = 'ADD' CounterValue 'ON' TypeOrPage .
7960: TypeOrPage = 'Page' [ '(' ViewID ')' ] /
1.16 cvs 7961: [ '*' ] ElemID .
1.1 cvs 7962: CounterValue = NUMBER .
7963:
1.30 cvs 7964: ConstSeq = Const < Const > .
1.1 cvs 7965: Const = ConstID '=' ConstType ConstValue ';' .
7966: ConstID = NAME .
1.41 vatton 7967: ConstType = 'Text' [ Script ] / 'Symbol' /
1.1 cvs 7968: 'Graphics' / 'Picture' .
7969: ConstValue = STRING .
1.41 vatton 7970: Script = NAME .
1.1 cvs 7971:
1.30 cvs 7972: VarSeq = Variable < Variable > .
1.1 cvs 7973: Variable = VarID ':' FunctionSeq ';' .
7974: VarID = NAME .
1.30 cvs 7975: FunctionSeq = Function < Function > .
1.1 cvs 7976: Function = 'DATE' / 'FDATE' /
7977: 'DocName' / 'DirName' /
1.38 cvs 7978: 'ElemName' / 'AttributeName' / 'AttributeValue' /
1.1 cvs 7979: ConstID / ConstType ConstValue /
7980: AttrID /
7981: 'VALUE' '(' PageAttrCtr ','
7982: CounterStyle ')' .
7983: PageAttrCtr = 'PageNumber' [ '(' ViewID ')' ] /
7984: [ MinMax ] CounterID / AttrID .
7985: CounterStyle = 'Arabic' / 'LRoman' / 'URoman' /
7986: 'Uppercase' / 'Lowercase' .
7987: MinMax = 'MaxRangeVal' / 'MinRangeVal' .
7988:
1.30 cvs 7989: BoxSeq = Box < Box > .
1.1 cvs 7990: Box = 'FORWARD' BoxID ';' /
7991: BoxID ':' ViewRuleSeq .
7992: BoxID = NAME .
7993:
1.30 cvs 7994: PresentSeq = Present < Present > .
1.1 cvs 7995: Present = [ '*' ] [ FirstSec ] ElemID ':'
7996: ViewRuleSeq .
7997: FirstSec = 'First' / 'Second' .
7998:
1.30 cvs 7999: PresAttrSeq = PresAttr < PresAttr > .
1.1 cvs 8000: PresAttr = AttrID [ '(' [ FirstSec ] ElemID ')' ]
8001: [ AttrRelation ] ':' ViewRuleSeq .
8002: AttrID = NAME .
8003: AttrRelation = '=' AttrVal /
1.30 cvs 8004: '>' [ '-' ] MinValue /
1.1 cvs 8005: '<' [ '-' ] MaxValue /
8006: 'IN' '[' [ '-' ] LowerBound '..'
8007: [ '-' ] UpperBound ']' /
8008: 'GREATER' AttrID /
8009: 'EQUAL' AttrID /
8010: 'LESS' AttrID .
8011: AttrVal = [ '-' ] EqualNum / EqualText / AttrValue .
8012: MinValue = NUMBER .
8013: MaxValue = NUMBER .
8014: LowerBound = NUMBER .
8015: UpperBound = NUMBER.
8016: EqualNum = NUMBER .
8017: EqualText = STRING .
8018: AttrValue = NAME .
8019:
1.30 cvs 8020: ViewRuleSeq = 'BEGIN' < RulesAndCond > < ViewRules >
1.1 cvs 8021: 'END' ';' /
8022: ViewRules / CondRules / Rule .
8023: RulesAndCond = CondRules / Rule .
8024: ViewRules = 'IN' ViewID CondRuleSeq .
1.30 cvs 8025: CondRuleSeq = 'BEGIN' < RulesAndCond > 'END' ';' /
1.1 cvs 8026: CondRules / Rule .
1.30 cvs 8027: CondRules = CondRule < CondRule >
1.1 cvs 8028: [ 'Otherwise' RuleSeq ] .
8029: CondRule = 'IF' ConditionSeq RuleSeq .
1.30 cvs 8030: RulesSeq = 'BEGIN' Rule < Rule > 'END' ';' / Rule .
1.1 cvs 8031:
1.30 cvs 8032: ConditionSeq = Condition < 'AND' Condition > .
1.6 cvs 8033: Condition = [ 'NOT' ] [ 'Target' ] ConditionElem .
8034: ConditionElem = 'First' / 'Last' /
8035: [ 'Immediately' ] 'Within' [ NumParent ]
8036: ElemID [ ExtStruct ] /
8037: ElemID /
8038: 'Referred' / 'FirstRef' / 'LastRef' /
8039: 'ExternalRef' / 'InternalRef' / 'CopyRef' /
1.44 quint 8040: [ 'Inherited' ] AttrID [ '=' Value ] /
1.6 cvs 8041: 'AnyAttributes' / 'FirstAttr' / 'LastAttr' /
8042: 'UserPage' / 'StartPage' / 'ComputedPage' /
1.33 cvs 8043: 'Empty' / 'Root' /
1.6 cvs 8044: '(' [ MinMax ] CounterName CounterCond ')' /
8045: CondPage '(' CounterID ')' .
8046: NumParent = [ GreaterLess ] NParent .
1.30 cvs 8047: GreaterLess = '>' / '<' .
1.6 cvs 8048: NParent = NUMBER.
1.30 cvs 8049: CounterCond = '<' MaxCtrVal / '>' MinCtrVal /
1.6 cvs 8050: '=' EqCtrVal /
8051: 'IN' '[' ['-'] MinCtrBound '..'
8052: ['-'] MaxCtrBound ']' .
8053: PageCond = 'Even' / 'Odd' / 'One' .
8054: MaxCtrVal = NUMBER .
8055: MinCtrVal = NUMBER .
8056: EqCtrVal = NUMBER .
8057: MaxCtrBound = NUMBER .
8058: MinCtrBound = NUMBER .
1.1 cvs 8059:
1.34 cvs 8060: Rule = Property ';' / PresFunc ';' .
8061: Property = 'VertRef' ':' HorizPosition /
1.1 cvs 8062: 'HorizRef' ':' VertPosition /
8063: 'VertPos' ':' VPos /
8064: 'HorizPos' ':' HPos /
1.49 ! quint 8065: 'Float' ':' FloatInherit /
! 8066: 'Clear' ':' ClearInherit /
1.1 cvs 8067: 'Height' ':' Extent /
8068: 'Width' ':' Extent /
8069: 'VertOverflow' ':' Boolean /
8070: 'HorizOverflow' ':' Boolean /
1.26 cvs 8071: 'MarginTop' ':' MarginWidth /
8072: 'MarginRight' ':' MarginWidth /
8073: 'MarginBottom' ':' MarginWidth /
8074: 'MarginLeft' ':' MarginWidth /
8075: 'PaddingTop' ':' PaddingWidth /
8076: 'PaddingRight' ':' PaddingWidth /
8077: 'PaddingBottom' ':' PaddingWidth /
8078: 'PaddingLeft' ':' PaddingWidth /
8079: 'BorderTopWidth' ':' BorderWidth /
8080: 'BorderRightWidth' ':' BorderWidth /
8081: 'BorderBottomWidth' ':' BorderWidth /
8082: 'BorderLeftWidth' ':' BorderWidth /
8083: 'BorderTopColor' ':' BorderColor /
8084: 'BorderRightColor' ':' BorderColor /
8085: 'BorderBottomColor' ':' BorderColor /
8086: 'BorderLeftColor' ':' BorderColor /
8087: 'BorderTopStyle' ':' BorderStyle /
8088: 'BorderRightStyle' ':' BorderStyle /
8089: 'BorderBottomStyle' ':' BorderStyle /
8090: 'BorderLeftStyle' ':' BorderStyle .
1.1 cvs 8091: 'LineSpacing' ':' DistOrInherit /
8092: 'Indent' ':' DistOrInherit /
8093: 'Adjust' ':' AlignOrInherit /
8094: 'Hyphenate' ':' BoolInherit /
1.40 quint 8095: 'Direction' ':' DirInherit /
1.43 quint 8096: 'UnicodeBidi' ':' BidiInherit /
1.1 cvs 8097: 'PageBreak' ':' Boolean /
8098: 'LineBreak' ':' Boolean /
8099: 'InLine' ':' Boolean /
8100: 'NoBreak1' ':' AbsDist /
8101: 'NoBreak2' ':' AbsDist /
8102: 'Gather' ':' Boolean /
8103: 'Visibility' ':' NumberInherit /
8104: 'Size' ':' SizeInherit /
8105: 'Font' ':' NameInherit /
8106: 'Style' ':' StyleInherit /
1.23 cvs 8107: 'Weight' ':' WeightInherit /
1.1 cvs 8108: 'Underline' ':' UnderLineInherit /
8109: 'Thickness' ':' ThicknessInherit /
8110: 'Depth' ':' NumberInherit /
8111: 'LineStyle' ':' LineStyleInherit /
8112: 'LineWeight' ':' DistOrInherit /
8113: 'FillPattern' ':' NameInherit /
1.30 cvs 8114: 'Background' ':' Color /
8115: 'Foreground' ':' Color /
1.47 quint 8116: 'Opacity' ':' OpacityInherit /
8117: 'FillOpacity' ':' OpacityInherit /
8118: 'StrokeOpacity' ':' OpacityInherit /
1.1 cvs 8119: 'Content' ':' VarConst .
8120: PresFunc = Creation '(' BoxID ')' /
8121: 'Line' /
8122: 'NoLine' /
8123: 'Page' '(' BoxID ')' /
1.13 cvs 8124: 'Copy' '(' BoxTypeToCopy ')' /
8125: 'ShowBox' /
1.18 cvs 8126: 'BackgroundPicture' ':' FileName /
8127: 'PictureMode' ':' PictMode .
1.1 cvs 8128:
8129: BoxTypeToCopy = BoxID [ ExtStruct ] /
8130: ElemID [ ExtStruct ] .
8131: ExtStruct = '(' ElemID ')' .
8132:
8133: Distance = [ Sign ] AbsDist .
8134: Sign = '+' / '-' .
8135: AbsDist = IntegerOrAttr [ '.' DecimalPart ]
8136: [ Unit ] .
8137: IntegerOrAttr = IntegerPart / AttrID .
8138: IntegerPart = NUMBER .
8139: DecimalPart = NUMBER .
8140: Unit = 'em' / 'ex' / 'cm' / 'mm' / 'in' / 'pt' /
8141: 'pc' / 'px' / '%' .
8142:
8143: HPos = 'nil' / VertAxis '=' HorizPosition
8144: [ 'UserSpecified' ] .
8145: VPos = 'nil' / HorizAxis '=' VertPosition
8146: [ 'UserSpecified' ] .
8147: VertAxis = 'Left' / 'VMiddle' / 'VRef' / 'Right' .
8148: HorizAxis = 'Top' / 'HMiddle' / 'HRef' / 'Bottom' .
8149:
1.6 cvs 8150: VertPosition = Reference '.' HorizAxis [ Distance ] .
8151: HorizPosition = Reference '.' VertAxis [ Distance ] .
8152: Reference = 'Enclosing' [ BoxTypeNot ] /
8153: 'Enclosed' [ BoxTypeNot ] /
8154: 'Previous' [ BoxTypeNot ] /
8155: 'Next' [ BoxTypeNot ] /
8156: 'Referred' [ BoxTypeNot ] /
8157: 'Creator' /
8158: 'Root' /
8159: '*' /
8160: BoxOrType .
8161: BoxOrType = BoxID /
8162: [ '*' ] [ FirstSec ] ElemID /
1.17 cvs 8163: 'AnyElem' / 'AnyBox' /
8164: 'ElemWithAttr' AttrID .
1.6 cvs 8165: BoxTypeNot = [ 'NOT' ] BoxOrType .
1.49 ! quint 8166:
! 8167: FloatInherit = Link '=' / 'Left' / 'Right' / 'None' .
! 8168: ClearInherit = Link '=' / 'None' / 'Left' / 'Right' / 'Both' .
1.6 cvs 8169:
8170: Extent = Reference '.' HeightWidth
8171: [ Relation ] [ 'Min' ] /
8172: AbsDist [ 'UserSpecified' ] [ 'Min' ] /
8173: HPos / VPos .
8174: HeightWidth = 'Height' / 'Width' .
8175: Relation = '*' ExtentAttr '%' / Distance .
8176: ExtentAttr = ExtentVal / AttrID .
8177: ExtentVal = NUMBER .
1.26 cvs 8178:
8179: MarginWidth = InheritParent / 'Auto' / Distance .
8180: PaddingWidth = InheritParent / Distance .
8181: BorderWidth = InheritParent / 'Thin' / 'Medium' / 'Thick' / Distance .
8182: BorderColor = InheritParent / 'Transparent' / 'Foreground' /
8183: ColorName .
8184: BorderStyle = InheritParent /
8185: 'None' / 'Hidden' / 'Dotted' / 'Dashed' / 'Solid' /
8186: 'Double' / 'Groove' / 'Ridge' / 'Inset' / 'Outset' .
1.27 cvs 8187: InheritParent = 'Enclosing' '=' / 'Creator' '=' .
1.26 cvs 8188: ColorName = NAME .
1.6 cvs 8189:
8190: Inheritance = Kinship InheritedValue .
8191: Kinship = 'Enclosing' / 'GrandFather'/ 'Enclosed' /
8192: 'Previous' / 'Creator' .
8193: InheritedValue = '+' PosIntAttr [ 'Max' maximumA ] /
8194: '-' NegIntAttr [ 'Min' minimumA ] /
8195: '=' .
8196: PosIntAttr = PosInt / AttrID .
8197: PosInt = NUMBER .
8198: NegIntAttr = NegInt / AttrID .
8199: NegInt = NUMBER .
8200: maximumA = maximum / AttrID .
8201: maximum = NUMBER .
8202: minimumA = minimum / AttrID .
8203: minimum = NUMBER .
8204:
8205: AlignOrInherit = Kinship '=' / Alignment .
8206: Alignment = 'Left' / 'Right' / 'VMiddle' /
8207: 'LeftWithDots' .
1.1 cvs 8208:
1.40 quint 8209: DirInherit = 'ltr' / 'rtl' / Kinship '=' .
1.43 quint 8210: BidiInherit = 'Normal' / 'Embed' / 'Override' / Kinship '=' .
1.40 quint 8211:
1.6 cvs 8212: DistOrInherit = Kinship InheritedDist / Distance .
8213: InheritedDist = '=' / '+' AbsDist / '-' AbsDist .
1.1 cvs 8214:
1.6 cvs 8215: BoolInherit = Boolean / Kinship '=' .
8216: Boolean = 'Yes' / 'No' .
1.1 cvs 8217:
1.6 cvs 8218: NumberInherit = Integer / AttrID / Inheritance .
8219: Integer = NUMBER .
1.1 cvs 8220:
8221: LineStyleInherit= Kinship '=' / 'Solid' / 'Dashed' /
8222: 'Dotted' .
8223:
1.6 cvs 8224: SizeInherit = SizeAttr [ 'pt' ] / Kinship InheritedSize .
8225: InheritedSize = '+' SizeAttr [ 'pt' ]
8226: [ 'Max' MaxSizeAttr ] /
8227: '-' SizeAttr [ 'pt' ]
8228: [ 'Min' MinSizeAttr ] /
1.22 cvs 8229: '*' PercentSizeAttr '%' /
1.6 cvs 8230: '=' .
8231: SizeAttr = Size / AttrID .
8232: Size = NUMBER .
8233: MaxSizeAttr = MaxSize / AttrID .
8234: MaxSize = NUMBER .
8235: MinSizeAttr = MinSize / AttrID .
8236: MinSize = NUMBER .
1.22 cvs 8237: PercentSizeAttr = PercentSize / AttrID .
8238: PercentSize = NUMBER .
1.6 cvs 8239:
8240: NameInherit = Kinship '=' / FontName .
8241: FontName = NAME .
1.30 cvs 8242: Color = 'Transparent' / Kinship '=' / FontName .
1.47 quint 8243: OpacityInherit = OpPercent '%' / AttrID / Inheritance .
8244: OpPercent = NUMBER .
1.6 cvs 8245: StyleInherit = Kinship '=' /
1.23 cvs 8246: 'Roman' / 'Italics' / 'Oblique' .
8247: WeightInherit = Kinship '=' /
8248: 'Normal' / 'Bold' .
1.1 cvs 8249: UnderLineInherit= Kinship '=' /
1.6 cvs 8250: 'NoUnderline' / 'Underlined' /
8251: 'Overlined' / 'CrossedOut' .
1.1 cvs 8252: ThicknessInherit= Kinship '=' / 'Thick' / 'Thin' .
1.13 cvs 8253:
8254: FileName = STRING .
8255: PictMode = 'NormalSize' / 'Scale' /
8256: 'RepeatXY' / 'RepeatX' / 'RepeatY' .
1.1 cvs 8257:
1.6 cvs 8258: VarConst = ConstID / ConstType ConstValue /
8259: VarID / '(' FunctionSeq ')' /
8260: ElemID .
8261:
8262: Creation = Create [ 'Repeated' ] .
8263: Create = 'CreateFirst' / 'CreateLast' /
8264: 'CreateBefore' / 'CreateAfter' /
8265: 'CreateEnclosing' .
8266:
1.30 cvs 8267: TransmitSeq = Transmit < Transmit > .
1.6 cvs 8268: Transmit = TypeOrCounter 'To' ExternAttr
8269: '(' ElemID ')' ';' .
8270: TypeOrCounter = CounterID / ElemID .
8271: ExternAttr = NAME .
1.1 cvs 8272:
1.18 cvs 8273: END</pre>
8274: </div>
1.1 cvs 8275:
1.18 cvs 8276: <div class="section">
1.37 cvs 8277: <h2><a name="sectb64" id="sectb64">The T language</a></h2>
1.18 cvs 8278: <pre>TransSchema = 'TRANSLATION' ElemID ';'
1.1 cvs 8279: [ 'LINELENGTH' LineLength ';' ]
8280: [ 'LINEEND' CHARACTER ';' ]
8281: [ 'LINEENDINSERT' STRING ';' ]
8282: [ 'BUFFERS' BufferSeq ]
8283: [ 'COUNTERS' CounterSeq ]
8284: [ 'CONST' ConstSeq ]
8285: [ 'VAR' VariableSeq ]
8286: 'RULES' ElemSeq
8287: [ 'ATTRIBUTES' AttrSeq ]
8288: [ 'PRESENTATION' PresSeq ]
1.30 cvs 8289: < 'TEXTTRANSLATE' TextTransSeq >
1.1 cvs 8290: [ 'SYMBTRANSLATE' TransSeq ]
8291: [ 'GRAPHTRANSLATE' TransSeq ]
8292: 'END' .
8293:
8294: LineLength = NUMBER .
8295:
1.30 cvs 8296: BufferSeq = Buffer < Buffer > .
1.46 quint 8297: Buffer = BufferID [ '(' BufferType ')' ] ';' .
1.1 cvs 8298: BufferID = NAME .
1.46 quint 8299: BufferType = 'Picture' / 'Variable' .
1.1 cvs 8300:
1.30 cvs 8301: CounterSeq = Counter < Counter > .
1.1 cvs 8302: Counter = CounterID [ ':' CounterFunc ] ';' .
8303: CounterID = NAME .
8304: CounterFunc = 'Rank' 'of' ElemID [ SLevelAsc ]
8305: [ 'Init' AttrID ] /
8306: 'Rlevel' 'of' ElemID /
8307: 'Set' InitValue 'On' ElemID
8308: 'Add' Increment 'On' ElemID
8309: [ 'Init' AttrID ] .
8310: SLevelAsc = [ '-' ] LevelAsc .
8311: LevelAsc = NUMBER .
8312: InitValue = NUMBER .
8313: Increment = NUMBER .
8314: ElemID = NAME .
8315: AttrID = NAME .
8316:
1.30 cvs 8317: ConstSeq = Const < Const > .
1.1 cvs 8318: Const = ConstID '=' ConstValue ';' .
8319: ConstID = NAME .
8320: ConstValue = STRING .
8321:
1.30 cvs 8322: VariableSeq = Variable < Variable > .
8323: Variable = VarID ':' Function < Function > ';' .
1.1 cvs 8324: VarID = NAME .
8325: Function = 'Value' '(' CounterID [ ':' Length ]
8326: [ ',' CounterStyle ] ')' /
8327: 'FileDir' / 'FileName' / 'Extension' /
8328: 'DocumentName' / 'DocumentDir' /
8329: ConstID / CharString /
8330: BufferID / AttrID .
8331: Length = NUMBER .
8332: CounterStyle= 'Arabic' / 'LRoman' / 'URoman' /
8333: 'Uppercase' / 'Lowercase' .
8334: CharString = STRING .
8335:
1.30 cvs 8336: ElemSeq = TransType < TransType > .
1.1 cvs 8337: TransType = [ FirstSec ] ElemID ':' RuleSeq .
8338: FirstSec = 'First' / 'Second' .
1.30 cvs 8339: RuleSeq = Rule / 'BEGIN' < Rule > 'END' ';' .
1.1 cvs 8340: Rule = SimpleRule / ConditionBlock .
8341: ConditionBlock= 'IF' ConditionSeq SimpleRuleSeq .
1.30 cvs 8342: SimpleRuleSeq = 'BEGIN' < SimpleRule > 'END' ';' /
1.1 cvs 8343: SimpleRule .
8344:
8345: ConditionSeq = Condition [ 'AND' Condition ] .
8346: Condition = [ 'NOT' ] [ 'Target' ] Cond .
8347: Cond = CondElem / CondAscend .
8348: CondElem = 'FirstRef' / 'LastRef' /
8349: 'ExternalRef' /
1.41 vatton 8350: 'Script' '=' Script /
1.1 cvs 8351: 'ComputedPage' / 'StartPage' /
8352: 'UserPage' / 'ReminderPage' /
8353: 'Empty' /
1.18 cvs 8354: ElemID /
1.1 cvs 8355: 'FirstAttr' / 'LastAttr' .
8356: CondAscend = [ Ascend ] CondOnAscend .
8357: Ascend = '*' / 'Parent' / 'Ancestor' LevelOrType .
8358: LevelOrType = CondRelLevel / ElemID [ ExtStruct ] .
8359: CondRelLevel = NUMBER .
8360: CondOnAscend = 'First' / 'Last' /
8361: 'Referred' /
8362: [ 'Immediately' ] 'Within' [ NumParent ]
8363: ElemID [ ExtStruct ] /
8364: 'Attributes' /
8365: AttrID [ RelatAttr ] /
8366: 'Presentation' /
1.34 cvs 8367: PresRule .
1.1 cvs 8368: NumParent = [ GreaterLess ] NParent .
1.30 cvs 8369: GreaterLess = '>' / '<' .
1.1 cvs 8370: NParent = NUMBER.
1.41 vatton 8371: Script = NAME .
1.1 cvs 8372: RelatAttr = '=' Value /
1.30 cvs 8373: '>' [ '-' ] Minimum /
1.1 cvs 8374: '<' [ '-' ] Maximum /
8375: 'IN' '[' [ '-' ] MinInterval '..'
8376: [ '-' ] MaxInterval ']' .
8377: Value = [ '-' ] IntegerVal / TextVal / AttrValue .
8378: Minimum = NUMBER .
8379: Maximum = NUMBER .
8380: MinInterval = NUMBER .
8381: MaxInterval = NUMBER .
8382: IntegerVal = NUMBER .
8383: TextVal = STRING .
8384: AttrValue = NAME .
8385:
8386: SimpleRule = 'Create' [ 'IN' VarID ] Object
8387: [ Position ] ';' /
8388: 'Write' Object [ Position ] ';' /
8389: 'Read' BufferID [ Position ] ';' /
8390: 'Include' File [ Position ] ';' /
1.6 cvs 8391: 'Get' [ RelPosition ] ElemID
8392: [ ExtStruct ]
8393: [ Position ] ';' /
1.1 cvs 8394: 'Copy' [ RelPosition ] ElemID
8395: [ ExtStruct ]
8396: [ Position ] ';' /
8397: 'Use' TrSchema [ 'For' ElemID ] ';' /
8398: 'Remove' ';' /
1.31 cvs 8399: 'Ignore' ';' /
1.1 cvs 8400: 'NoTranslation' ';' /
8401: 'NoLineBreak' ';' /
8402: 'ChangeMainFile' VarID [ Position ] ';' /
1.14 cvs 8403: 'RemoveFile' VarID [ Position ] ';' /
1.10 cvs 8404: 'Set' CounterID InitValue [ Position ] ';' /
8405: 'Add' CounterID Increment [ Position ] ';' /
1.25 cvs 8406: 'Indent' [ 'IN' VarID ] Indent [ Position ] ';' .
1.10 cvs 8407:
1.25 cvs 8408: Indent = 'Suspend' / 'Resume' / [ IndentSign ] IndentValue .
1.10 cvs 8409: IndentSign = '+' / '-' .
8410: IndentValue = NUMBER .
1.1 cvs 8411:
8412: Object = ConstID / CharString /
8413: BufferID /
8414: VarID /
1.30 cvs 8415: '(' Function < Function > ')' /
1.21 cvs 8416: [ 'Translated' ] AttrID /
1.1 cvs 8417: 'Value' /
8418: 'Content' /
8419: 'Attributes' /
8420: 'Presentation' /
8421: 'RefId' /
8422: 'PairId' /
8423: 'FileDir' / 'FileName' / 'Extension' /
8424: 'DocumentName' / 'DocumentDir' /
8425: [ 'Referred' ] ReferredObject .
8426: Position = 'After' / 'Before' .
8427:
1.6 cvs 8428: ReferredObject= VarID /
8429: ElemID [ ExtStruct ] /
8430: 'RefId' /
8431: 'DocumentName' / 'DocumentDir' .
1.1 cvs 8432:
1.6 cvs 8433: File = FileName / BufferID .
8434: FileName = STRING .
1.1 cvs 8435:
1.6 cvs 8436: RelPosition = 'Included' / 'Referred' .
8437: ExtStruct = '(' ElemID ')' .
1.1 cvs 8438:
1.6 cvs 8439: TrSchema = NAME .
8440:
1.30 cvs 8441: AttrSeq = TransAttr < TransAttr > .
1.6 cvs 8442: TransAttr = AttrID [ '(' ElemID ')' ]
8443: [ RelatAttr ] ':' RuleSeq .
8444:
1.30 cvs 8445: PresSeq = PresTrans < PresTrans > .
1.6 cvs 8446: PresTrans = PresRule ':' RuleSeq .
8447: PresRule = 'Size' [ PresRelation ] /
8448: 'Indent' [ PresRelation ] /
8449: 'LineSpacing' [ PresRelation ] /
8450: 'Adjust' [ '=' AdjustVal ] /
8451: 'Hyphenate' [ '=' BoolVal ] /
8452: 'Style' [ '=' StyleVal ] /
1.24 cvs 8453: 'Weight' [ '=' WeightVal ] /
1.6 cvs 8454: 'Font' [ '=' FontVal ] /
8455: 'UnderLine' [ '=' UnderLineVal ] /
8456: 'Thickness' [ '=' ThicknessVal ] /
8457: 'LineStyle' [ '=' LineStyleVal ] /
8458: 'LineWeight' [ PresRelation ] /
8459: 'FillPattern' [ '=' Pattern ] /
8460: 'Background' [ '=' Color ] /
8461: 'Foreground' [ '=' Color ] .
8462:
8463: PresRelation = '=' PresValue /
1.30 cvs 8464: '>' [ '-' ] PresMinimum /
1.6 cvs 8465: '<' [ '-' ] PresMaximum /
8466: 'IN' '[' [ '-' ] PresIntervalMin '..'
8467: [ '-' ] PresIntervalMax ']' .
1.35 cvs 8468: AdjustVal = 'Left' / 'Right' / 'VMiddle' / 'Justify' /
1.6 cvs 8469: 'LeftWithDots' .
8470: BoolVal = 'Yes' / 'No' .
1.24 cvs 8471: StyleVal = 'Roman' / 'Italics' / 'Oblique' .
8472: WeightVal = 'Normal' / 'Bold' .
1.6 cvs 8473: FontVal = 'Times' / 'Helvetica' / 'Courier' .
8474: UnderLineVal = 'NoUnderline' / 'UnderLined' /
8475: 'OverLined' / 'CrossedOut' .
8476: ThicknessVal = 'Thick' / 'Thin' .
8477: LineStyleVal = 'Solid' / 'Dashed' / 'Dotted' .
8478: Pattern = NAME .
8479: Color = NAME .
8480: PresMinimum = NUMBER .
8481: PresMaximum = NUMBER .
1.1 cvs 8482: PresIntervalMin= NUMBER .
8483: PresIntervalMax= NUMBER .
1.6 cvs 8484: PresValue = [ '-' ] PresVal .
8485: PresVal = NUMBER .
1.1 cvs 8486:
1.41 vatton 8487: TextTransSeq = [ Script ] TransSeq .
8488: Script = NAME .
1.30 cvs 8489: TransSeq = 'BEGIN' < Translation > 'END' ';' /
1.6 cvs 8490: Translation .
1.30 cvs 8491: Translation = Source [ '->' Target ] ';' .
1.6 cvs 8492: Source = STRING .
1.18 cvs 8493: Target = STRING .</pre>
8494: </div>
1.37 cvs 8495: <hr />
1.18 cvs 8496: </div>
1.1 cvs 8497:
1.18 cvs 8498: <div class="chapter">
1.37 cvs 8499: <h1><a name="sect7" id="sect7">Character coding</a></h1>
1.1 cvs 8500:
1.18 cvs 8501: <div class="section">
1.37 cvs 8502: <h2><a name="sectb71" id="sectb71">Characters</a></h2>
1.1 cvs 8503:
1.43 quint 8504: <p>The characters of the Latin script follow the encoding defined in the ISO
8505: 8859-1 (ISO Latin-1) standard. The characters of the Greek script follow the
8506: encoding defined by Adobe for its Symbol font (Adobe FontSpecific).</p>
1.37 cvs 8507:
8508: <p>Characters whose octal code is greater than 0200 are written in the form
8509: of their octal code preceded by a backslash character (``\''). For example,
8510: the French word 'Résumé' is written <tt>R\351sum\351</tt>.</p>
1.30 cvs 8511:
8512: <p>To the ISO 8859-1 encoding four characters with the following codes have
1.37 cvs 8513: been added:<br />
8514: <tt>212</tt>: line break<br />
8515: <tt>240</tt>: sticky space<br />
8516: <tt>201</tt>: thin space<br />
1.18 cvs 8517: <tt>202</tt>: en space</p>
1.30 cvs 8518:
8519: <p>The <tt>212</tt> character is a ``line break'' character which forces a
1.37 cvs 8520: line break. The <tt>240</tt> character is a ``sticky space'', which cannot be
1.18 cvs 8521: replaced by a line break.</p>
8522: </div>
1.1 cvs 8523:
1.18 cvs 8524: <div class="section">
1.37 cvs 8525: <h2><a name="sectb72" id="sectb72">Symbols</a></h2>
1.1 cvs 8526:
1.37 cvs 8527: <p>The table below gives the codes for the symbols of Thot. Symbols can be
8528: used in presentation schemas constants and in transcoding rules of
8529: translation schemas. Each symbol is represented by a single character.</p>
1.18 cvs 8530: <ul>
1.40 quint 8531: <li><tt>r</tt> : a radical</li>
8532: <li><tt>i</tt> : a simple integral</li>
8533: <li><tt>c</tt> : a curvilinear integral</li>
8534: <li><tt>d</tt> : a double integral</li>
8535: <li><tt>t</tt> : a triple integral</li>
1.39 cvs 8536: <li><code>o</code>: an over brace</li>
8537: <li><code>u</code>: an under brace</li>
1.40 quint 8538: <li><tt>S</tt> : the summation symbol</li>
8539: <li><tt>P</tt> : the product symbol</li>
8540: <li><tt>U</tt> : the union symbol</li>
8541: <li><tt>I</tt> : the intersection symbol</li>
8542: <li><tt>R</tt> : a right arrow</li>
8543: <li><tt>L</tt> : a left arrow</li>
8544: <li><tt><</tt> : an opening pointy bracket</li>
8545: <li><tt>></tt> : a closing pointy bracket</li>
8546: <li><tt>^</tt> : an up arrow</li>
8547: <li><tt>V</tt> : a down arrow</li>
8548: <li><tt>(</tt> : an opening parenthesis</li>
8549: <li><tt>)</tt> : a closing parenthesis</li>
8550: <li><tt>{</tt> : an opening brace</li>
8551: <li><tt>}</tt> : a closing brace</li>
8552: <li><tt>[</tt> : an opening square bracket</li>
8553: <li><tt>]</tt> : a closing square bracket</li>
1.18 cvs 8554: </ul>
8555: </div>
1.1 cvs 8556:
1.18 cvs 8557: <div class="section">
1.37 cvs 8558: <h2><a name="sectb73" id="sectb73">Graphical elements</a></h2>
1.1 cvs 8559:
1.30 cvs 8560: <p>The table below gives the codes for the graphical elements of Thot. These
1.1 cvs 8561: elements can be used in presentation schemas constants and in transcoding
1.37 cvs 8562: rules of translation schemas. Each graphical element is represented by a
1.18 cvs 8563: single character.</p>
8564: <ul>
1.30 cvs 8565: <li>a: a circle</li>
8566: <li><p><tt>A</tt>: an open curve with an arrow head at the end</p>
8567: </li>
1.40 quint 8568: <li><tt>b</tt> : a horizontal line along the lower side of the box</li>
8569: <li><tt>B</tt> : an open curve</li>
8570: <li><tt>c</tt> : an ellipse inscribed in the box</li>
8571: <li><tt>C</tt> : a rectangle with rounded corners</li>
8572: <li><tt>D</tt> : an open curve with two arrow heads</li>
8573: <li><tt>e</tt> : The northwest/southeast diagonal of the box with an
8574: arrowhead at the bottom</li>
8575: <li><tt>E</tt> : The southwest/northeast diagonal of the box with an
8576: arrowhead at the top</li>
8577: <li><tt>F</tt> : an open curve with an arrow head at start</li>
8578: <li><tt>g</tt> : a line from the origin of the box to its opposite
8579: corner</li>
8580: <li><tt>h</tt> : a horizontal line as wide as the box and placed in its
8581: middle</li>
8582: <li><tt>l</tt> : a vertical line on the left side of the box</li>
8583: <li><tt>L</tt> : a lozenge</li>
8584: <li><tt>M</tt> : an open broken line with two arrow heads</li>
8585: <li><tt>N</tt> : an open broken line with an arrow head at start</li>
8586: <li><tt>o</tt> : The southwest/northeast diagonal of the box with an
8587: arrowhead at the bottom</li>
8588: <li><tt>O</tt> : The northwest/southeast diagonal of the box with an
8589: arrowhead at the top</li>
8590: <li><tt>p</tt> : a polygon</li>
8591: <li><tt>P</tt> : a rectangle with round corners and a horizontal bar at the
8592: top</li>
8593: <li><tt>Q</tt> : an ellipse with a horizontal bar at the top</li>
8594: <li><tt>r</tt> : a vertical line on the right side of the box</li>
8595: <li><tt>R</tt> : a rectangle which is the shape of the box</li>
8596: <li><tt>s</tt> : a closed curve</li>
8597: <li><tt>S</tt> : an open broken line</li>
8598: <li><tt>t</tt> : a horizontal line along the upper side of the box</li>
8599: <li><tt>U</tt> : an open broken line with an arrow head at the end</li>
8600: <li><tt>v</tt> : a vertical line as tall as the box and placed in its
8601: middle</li>
8602: <li><tt>V</tt> : a down arrow as tall as the box and in its middle</li>
1.30 cvs 8603: <li>w: a segment (2 points)</li>
1.40 quint 8604: <li><tt>W</tt> : the upper right corner</li>
1.30 cvs 8605: <li>x: a segment (2 points) with an arrow head at the end</li>
1.40 quint 8606: <li><tt>X</tt> : the lower right corner</li>
1.30 cvs 8607: <li>y: a segment (2 points) with an arrow head at the end</li>
1.40 quint 8608: <li><tt>Y</tt> : the lower left corner</li>
1.30 cvs 8609: <li>z: a segment (2 points) with an arrow head at the end</li>
1.40 quint 8610: <li><tt>Z</tt> : the upper left corner</li>
8611: <li><tt>space</tt> : a transparent element</li>
8612: <li><tt>^</tt> : an up arrow as tall as the box and in its middle</li>
8613: <li><tt>></tt> : a right arrow as long as the box's width and in its
8614: middle</li>
8615: <li><tt>></tt> : a left arrow as long as the box's width and in its
8616: middle</li>
8617: <li><tt>/</tt> : The southwest/northeast diagonal of the box</li>
8618: <li><tt>\</tt> : the northwest/southeast diagonal of the box</li>
1.18 cvs 8619: </ul>
1.37 cvs 8620: <hr />
1.18 cvs 8621: </div>
8622: </div>
8623: </body>
8624: </html>
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