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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:
1.35 cvs 18: <h4>Version of February 12, 2001</h4>
1.30 cvs 19:
20: <p>© 1996-2000 INRIA</p>
1.18 cvs 21: <hr>
22: </div>
23:
24: <div class="tableofcontents">
25: <h2><a href="languages.toc.html">Contents</a></h2>
26: <ul>
1.30 cvs 27: <li><big><a href="#sect2">The document model of Thot</a></big>
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>
39: <li><big><a href="#sect3">The S language</a></big>
40: <ul>
41: <li><strong><a href="#sectb31">Document meta-structure</a></strong>
42: <ul>
43: <li><a href="#sectc311">The basic types</a></li>
44: <li><a href="#sectc312">Constructed elements</a></li>
45: <li><a href="#sectc313">Logical structure constructors</a>
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="#sectc314">Associated Elements</a></li>
60: <li><a href="#sectc315">Attributes</a></li>
61: <li><a href="#sectc316">Discussion of the model</a></li>
62: </ul>
63: </li>
64: <li><strong><a href="#sectb32">The definition language for generic
65: structures</a></strong>
66: <ul>
67: <li><a href="#sectc321">Writing Conventions</a></li>
68: <li><a href="#sectc322">Extension schemas</a></li>
69: <li><a href="#sectc323">The general organization of structure
70: schemas</a></li>
71: <li><a href="#sectc324">The default presentation</a></li>
72: <li><a href="#sectc325">Global Attributes</a></li>
73: <li><a href="#sectc327">Structured elements</a></li>
74: <li><a href="#sectc328">Structure definitions</a>
75: <ul>
76: <li><small><a href="#sectd3281">List</a></small></li>
77: <li><small><a href="#sectd3282">Aggregate</a></small></li>
78: <li><small><a href="#sectd3283">Choice</a></small></li>
79: <li><small><a href="#sectd3284">Reference</a></small></li>
80: <li><small><a href="#sectd3285">Mark pairs</a></small></li>
81: </ul>
82: </li>
83: <li><a href="#sectc329">Imports</a></li>
84: <li><a href="#sectc3210">Extension rules</a></li>
85: <li><a href="#sectc3211">Associated elements</a></li>
86: <li><a href="#sectc3212">Units</a></li>
87: <li><a href="#sectc3213">Skeleton elements</a></li>
88: <li><a href="#sectc3214">Exceptions</a></li>
89: </ul>
90: </li>
91: <li><strong><a href="#sectb33">Some examples</a></strong>
92: <ul>
93: <li><a href="#sectc331">A class of documents: articles</a></li>
94: <li><a href="#sectc332">A class of objects: mathematical
95: formulas</a></li>
96: </ul>
97: </li>
98: </ul>
99: </li>
100: <li><big><a href="#sect4">The P language</a></big>
101: <ul>
102: <li><strong><a href="#sectb41">Document presentation</a></strong>
103: <ul>
104: <li><a href="#sectc411">Two levels of presentation</a></li>
105: <li><a href="#sectc412">Boxes</a></li>
106: <li><a href="#sectc413">Views and visibility</a></li>
107: <li><a href="#sectc414">Pages</a></li>
108: <li><a href="#sectc415">Numbering</a></li>
1.34 cvs 109: <li><a href="#sectc416">Presentation properties</a></li>
1.30 cvs 110: </ul>
111: </li>
112: <li><strong><a href="#sectb42">Presentation description
113: language</a></strong>
114: <ul>
115: <li><a href="#sectc421">The organization of a presentation
116: schema</a></li>
117: <li><a href="#sectc422">Views</a></li>
118: <li><a href="#sectc423">Print Views</a></li>
119: <li><a href="#sectc424">Counters</a></li>
120: <li><a href="#sectc425">Presentation constants</a></li>
121: <li><a href="#sectc426">Variables</a></li>
122: <li><a href="#sectc427">Default presentation rules</a></li>
123: <li><a href="#sectc428">Presentation and page layout boxes</a></li>
124: <li><a href="#sectc429">Presentation of structured elements</a></li>
125: <li><a href="#sectc4210">Logical attribute presentation</a></li>
126: <li><a href="#sectc4212">Value transmission rules</a></li>
127: <li><a href="#sectc4213">Presentation rules</a></li>
128: <li><a href="#sectc4214">Conditions applying to presentation
129: rules</a>
130: <ul>
131: <li><small><a href="#sectd42141">Conditions based on the logical
132: position of the element</a></small></li>
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>
149: <li><a href="#sectc4219">Box extents</a>
150: <ul>
151: <li><small><a href="#sectd42191">Fixed extents</a></small></li>
152: <li><small><a href="#sectd42192">Relative
153: extents</a></small></li>
154: <li><small><a href="#sectd42193">Elastic
155: extents</a></small></li>
156: </ul>
157: </li>
158: <li><a href="#sectc4220">Overflow</a></li>
159: <li><a href="#sectc4221">Inheritance</a></li>
160: <li><a href="#sectc4222">Line breaking</a>
161: <ul>
162: <li><small><a href="#sectd42221">Line spacing</a></small></li>
163: <li><small><a href="#sectd42222">First line
164: indentation</a></small></li>
165: <li><small><a href="#sectd42223">Alignment</a></small></li>
166: <li><small><a href="#sectd42225">Hyphenation</a></small></li>
167: <li><small><a href="#sectd42226">Avoiding line
168: breaking</a></small></li>
169: </ul>
170: </li>
171: <li><a href="#sectc4223">Page breaking and line breaking
172: conditions</a></li>
173: <li><a href="#sectc4224">Visibility</a></li>
1.34 cvs 174: <li><a href="#sectc4225">Character style properties</a>
1.30 cvs 175: <ul>
176: <li><small><a href="#sectd42251">Character size</a></small></li>
177: <li><small><a href="#sectd42252">Font and character
178: style</a></small></li>
179: <li><small><a href="#sectd42253">Underlining</a></small></li>
180: </ul>
181: </li>
182: <li><a href="#sectc4226">Stacking order</a></li>
183: <li><a href="#sectc4227">Line style</a></li>
184: <li><a href="#sectc4228">Line thickness</a></li>
185: <li><a href="#sectc4229">Fill pattern</a></li>
186: <li><a href="#sectc4230">Colors</a></li>
187: <li><a href="#sectc4230a">Background color and border</a></li>
188: <li><a href="#sectc4230b">Background pictures</a></li>
189: <li><a href="#sectc4231">Presentation box content</a></li>
190: <li><a href="#sectc4232">Presentation box creation</a></li>
191: <li><a href="#sectc4233">Page layout</a></li>
192: <li><a href="#sectc4234">Box copies</a></li>
193: </ul>
194: </li>
195: </ul>
196: </li>
197: <li><big><a href="#sect5">The T language</a></big>
198: <ul>
199: <li><strong><a href="#sectb51">Document translation</a></strong>
200: <ul>
201: <li><a href="#sectc511">Translation principles</a></li>
202: <li><a href="#sectc512">Translation procedure</a></li>
203: </ul>
204: </li>
205: <li><strong><a href="#sectb52">Translation definition
206: language</a></strong>
207: <ul>
208: <li><a href="#sectc521">Organization of a translation
209: schema</a></li>
210: <li><a href="#sectc522">Line length</a></li>
211: <li><a href="#sectc523">Buffers</a></li>
212: <li><a href="#sectc524">Counters</a></li>
213: <li><a href="#sectc525">Constants</a></li>
214: <li><a href="#sectc526">Variables</a></li>
215: <li><a href="#sectc527">Translating structure elements</a></li>
216: <li><a href="#sectc528">Conditional rules</a>
217: <ul>
218: <li><small><a href="#sectd5281">Conditions based on the logical
219: position of the element</a></small></li>
220: <li><small><a href="#sectd5282">Conditions on
221: references</a></small></li>
222: <li><small><a href="#sectd5284">Conditions on the
223: alphabets</a></small></li>
224: <li><small><a href="#sectd5285">Conditions on page
225: breaks</a></small></li>
226: <li><small><a href="#sectd5286">Conditions on the element's
227: content</a></small></li>
228: <li><small><a href="#sectd5288">Conditions on the presence of
229: specific presentation rules</a></small></li>
230: <li><small><a href="#sectd5289">Conditions on the presence of
231: logical attributes</a></small></li>
232: <li><small><a href="#sectd52810">Conditions on logical
233: attributes</a></small></li>
234: <li><small><a href="#sectd52811">Conditions on specific
235: presentation rules</a></small></li>
236: </ul>
237: </li>
238: <li><a href="#sectc529">Translation rules</a></li>
239: <li><a href="#sectc5210">The <tt>Create</tt> rule</a></li>
240: <li><a href="#sectc5211">The <tt>Write</tt> rule</a></li>
241: <li><a href="#sectc5212">The <tt>Read</tt> rule</a></li>
242: <li><a href="#sectc5213">The <tt>Include</tt> rule</a></li>
243: <li><a href="#sectc5214">The <tt>Get</tt> rule</a></li>
244: <li><a href="#sectc5215">The <tt>Copy</tt> rule</a></li>
245: <li><a href="#sectc5216">The <tt>Use</tt> rule</a></li>
246: <li><a href="#sectc5217">The <tt>Remove</tt> rule</a></li>
1.31 cvs 247: <li><a href="#sectc5217a">The <code>Ignore</code> rule</a></li>
1.30 cvs 248: <li><a href="#sectc5218">The <tt>NoTranslation</tt> rule</a></li>
249: <li><a href="#sectc5219">The <tt>NoLineBreak</tt> rule</a></li>
250: <li><a href="#sectc5220">The <tt>ChangeMainFile</tt> rule</a></li>
251: <li><a href="#sectc5220a">The <tt>RemoveFile</tt> rule</a></li>
252: <li><a href="#sectc5221">The <tt>Set</tt> and <tt>Add</tt>
253: rules</a></li>
254: <li><a href="#sectc5221a">The <tt>Indent</tt> rule</a></li>
255: <li><a href="#sectc5222">Rule application order</a></li>
256: <li><a href="#sectc5223">Translation of logical attributes</a></li>
257: <li><a href="#sectc5224">Translation of specific
258: presentations</a></li>
259: <li><a href="#sectc5225">Recoding of characters, symbols and
260: graphics</a></li>
261: </ul>
262: </li>
263: </ul>
264: </li>
265: <li><big><a href="#sect6">Language grammars</a></big>
266: <ul>
267: <li><strong><a href="#sectb61">The M meta-language</a></strong></li>
268: <li><strong><a href="#sectb62">The S language</a></strong></li>
269: <li><strong><a href="#sectb63">The P language</a></strong></li>
270: <li><strong><a href="#sectb64">The T language</a></strong></li>
271: </ul>
272: </li>
273: <li><big><a href="#sect7">Character coding</a></big>
274: <ul>
275: <li><strong><a href="#sectb71">Characters</a></strong></li>
276: <li><strong><a href="#sectb72">Symbols</a></strong></li>
277: <li><strong><a href="#sectb73">Graphical elements</a></strong></li>
278: </ul>
279: </li>
1.18 cvs 280: </ul>
281: <hr>
282: </div>
1.1 cvs 283:
1.18 cvs 284: <div class="chapter">
1.30 cvs 285: <h1><a name="sect2">The document model of Thot</a></h1>
1.1 cvs 286:
1.30 cvs 287: <p>All of the services which Thot provides to the user are based on the
288: system's internal document representation. This representation is itself
289: derived from the document model which underlies Thot. The model is presented
290: here, prior to the description of the languages which permit the generic
291: specification of documents.</p>
1.1 cvs 292:
1.18 cvs 293: <div class="section">
1.30 cvs 294: <h2><a name="sectb21">The logical structure of documents</a></h2>
1.1 cvs 295:
1.30 cvs 296: <p>The document model of Thot is primarily designed to allow the user to
297: operate on those entities which s/he has in mind when s/he works on a
298: document. The model makes no assumptions about the nature of these entities.
299: It is essentially these logical entities, such as paragraphs, sections,
300: chapters, notes, titles, and cross-references which give a document its
301: logical structure.</p>
302:
303: <p>Because of this model, the author can divide the document into chapters,
1.1 cvs 304: giving each one a title. The content of these chapters can be further divided
1.2 cvs 305: into sections, subsections, etc. The text is organized into successive
306: paragraphs, according to the content. In the writing phase, the lines, pages,
307: margins, spacing, fonts, and character styles are not very important. In fact,
308: if the system requires documents to be written in these terms, it gets in the
309: way. So, Thot's model is primarily based on the logical aspect of documents.
1.18 cvs 310: The creation of a model of this type essentially requires the definition :</p>
311: <ul>
1.30 cvs 312: <li>of the entities which can appear in the documents,</li>
313: <li>and the relations between these entities.</li>
1.18 cvs 314: </ul>
1.30 cvs 315:
316: <p>The choice of entities to include in the model can be subtle. Some
317: documents require chapters, while others only need various levels of sections.
318: Certain documents contain appendices, others don't. In different documents
319: the same logical entity may go by different names (e.g. ``Conclusion'' and
1.1 cvs 320: ``Summary''). Certain entities which are absolutely necessary in some
321: documents, such as clauses in a contract or the address of the recipient in a
1.18 cvs 322: letter, are useless in most other cases.</p>
1.30 cvs 323:
324: <p>The differences between documents result from more than just the entities
325: that appear in them, but also from the relationships between these entities
326: and the ways that they are linked. In certain documents, notes are spread
327: throughout the document, for example at the bottom of the page containing the
1.1 cvs 328: cross-reference to them, while in other documents they are collected at the
329: end of each chapter or even at the end of the work. As another example, the
330: introduction of some documents can contain many sections, while in other
331: documents, the introduction is restricted to be a short sequence of
1.18 cvs 332: paragraphs.</p>
1.30 cvs 333:
334: <p>All of this makes it unlikely that a single model can describe any document
335: at a relatively high level. It is obviously tempting to make up a list of
336: widely used entities, such as chapters, sections, paragraphs, and titles, and
337: then map all other entities onto the available choices. In this way, an
1.1 cvs 338: introduction can be supported as a chapter and a contract clause supported as
339: a paragraph or section. However, in trying to widen the range of usage of
340: certain entities, their meaning can be lost and the power of the model
341: reduced. In addition, while this widening partially solves the problem of
342: choosing entities, it does not solve the problem of their organization: when a
343: chapter must be composed of sections, how does one indicate that an
344: introduction has none when it is merely another chapter? One solution is to
345: include introductions in the list of supported entities. But then, how does
346: one distinguish those introductions which are allowed to have sections from
347: those which are not. Perhaps this could be done by defining two types of
348: introduction. Clearly, this approach risks an infinite expansion of the list
1.18 cvs 349: of widely used entities.</p>
350: </div>
1.1 cvs 351:
1.18 cvs 352: <div class="section">
1.30 cvs 353: <h2><a name="sectb22">Generic and specific structures</a></h2>
1.1 cvs 354:
1.30 cvs 355: <p>Thus, it is apparently impossible to construct an exhaustive inventory of
356: all those entities which are necessary and sufficient to precisely describe
357: any document. It also seems impossible to specify all possible arrangements of
1.18 cvs 358: these entities in a document. This is why Thot uses a <em>meta-model</em>
359: instead, which permits the description of numerous <em>models</em>, each one
360: describing a <em>class</em> of documents.</p>
1.30 cvs 361:
362: <p>A <em>class</em> is a set of documents having very similar structure. Thus,
1.1 cvs 363: the collection of research reports published by a laboratory constitutes a
364: class; the set of commercial proposals by the sales department of a company
365: constitutes another class; the set of articles published by a journal
366: constitutes a third class. Clearly, it is not possible to enumerate every
367: possible document class. It is also clear that new document classes must be
1.18 cvs 368: created to satisfy new needs and applications.</p>
1.30 cvs 369:
370: <p>To give a more rigorous definition of classes, we must introduce the ideas
371: of <em>generic structure</em> and <em>specific structure</em>. Each document
372: has a <em>specific structure</em> which organizes the various parts which
373: comprise it. We illustrate this with the help of a simple example comparing
374: two reports, A and B (<a href="#specstruct">see Figure</a>). The report A
375: contains an introduction followed by three chapters and a conclusion. The
376: first chapter contains two sections, the second, three sections. That is the
1.18 cvs 377: <em>specific</em> structure of document A. Similarly, the structure of
1.1 cvs 378: document B is: an introduction, two chapters, a conclusion; Chapter 1 has
379: three sections while Chapter 2 has four. The specific structures of these two
1.18 cvs 380: documents are thus different.</p>
1.1 cvs 381:
1.18 cvs 382: <div class="figure">
383: <hr>
384: <pre> Report A Report B
1.1 cvs 385: Introduction Introduction
386: Chapter 1 Chapter 1
387: Section 1.1 Section 1.1
388: Section 1.2 Section 1.2
389: Chapter 2 Section 1.3
390: Section 2.1 Chapter 2
391: Section 2.2 Section 2.1
392: Section 2.3 Section 2.2
393: Chapter 3 Section 2.3
394: Conclusion Section 2.4
1.18 cvs 395: Conclusion</pre>
1.30 cvs 396:
397: <p align="center"><em><a name="specstruct">Two specific
398: structures</a></em></p>
1.18 cvs 399: <hr>
1.30 cvs 400: </div>
401:
402: <p>The <em>generic structure</em> defines the ways in which specific
403: structures can be constructed. It specifies how to generate specific
404: structures. The reports A and B, though different, are constructed in
405: accordance with the same generic structure, which specifies that a report
406: contains an introduction followed by a variable number of chapters and a
407: conclusion, with each chapter containing a variable number of sections.</p>
408:
409: <p>There is a one-to-one correspondence between a class and a generic
410: structure: all the documents of a class are constructed in accordance with the
411: same generic structure. Hence the definition of the class: a class is a set
412: of documents whose specific structure is constructed in accordance with the
413: same generic structure. A class is characterized by its generic
414: structure.</p>
1.19 cvs 415:
1.30 cvs 416: <p>Thus, a generic structure can be considered to be a model at the level
417: which interests us, but only for one class of documents. When the definition
418: is limited to a single class of documents, it is possible to define a model
419: which does a good job of representing the documents of the class, including
420: the necessary entities and unencumbered by useless entities. The description
421: of the organization of the documents in the class can then be sufficiently
1.18 cvs 422: precise.</p>
423: </div>
1.1 cvs 424:
1.18 cvs 425: <div class="section">
1.30 cvs 426: <h2><a name="sectb23">Logical structure and physical structure</a></h2>
1.1 cvs 427:
1.30 cvs 428: <p>Generic structures only describe the <em>logical</em> organization of
1.18 cvs 429: documents, not their <em>physical</em> presentation on a screen or on sheets
1.1 cvs 430: of paper. However, for a document to be displayed or printed, its graphic
1.18 cvs 431: presentation must be taken into account.</p>
1.30 cvs 432:
433: <p>An examination of current printed documents shows that the details of
1.1 cvs 434: presentation essentially serve to bring out their logical structure. Outside
435: of some particular domains, notably advertising, the presentation is rarely
436: independent of the logical organization of the text. Moreover, the art of
437: typography consists of enhancing the organization of the text being set,
438: without catching the eye of the reader with overly pronounced effects. Thus,
439: italic and boldface type are used to emphasize words or expressions which have
440: greater significance than the rest of the text: keywords, new ideas,
441: citations, book titles, etc. Other effects highlight the organization of the
442: text: vertical space, margin changes, page breaks, centering, eventually
443: combined with the changes in the shapes or weight of the characters. These
444: effects serve to indicate the transitions between paragraphs, sections, or
445: chapters: an object's level in the logical structure of the document is shown
1.18 cvs 446: by the markedness of the effects.</p>
1.30 cvs 447:
448: <p>Since the model permits the description of all of the logical structure of
449: the document, the presentation can be derived from the model without being
1.1 cvs 450: submerged in the document itself. It suffices to use the logical structure of
451: the document to make the desired changes in its presentation: changes in type
1.18 cvs 452: size, type style, spacing, margin, centering, etc.</p>
1.30 cvs 453:
454: <p>Just as one cannot define a unique generic logical structure for all
455: document classes, one cannot define universal presentation rules which can be
456: applied to all document classes. For certain types of documents the chapter
457: titles will be centered on the page and printed in large, bold type. For
458: other documents, the same chapter titles will be printed in small, italic type
459: and aligned on the left margin.</p>
460:
461: <p>Therefore, it is necessary to base the presentation specifications for
1.1 cvs 462: documents on their class. Such a specification can be very fine-grained,
463: because the presentation is expressed in terms of the entities defined in the
464: generic logical structure of the class. Thus, it is possible to specify a
465: different presentation for the chapter titles and the section titles, and
466: similarly to specify titles for the sections according to their level in the
467: section hierarchy. The set of rules which specify the presentation of all the
1.18 cvs 468: elements defined in a generic logical structure is called a <em>generic
469: presentation</em>.</p>
1.30 cvs 470:
471: <p>There are several advantages derived from having a presentation linked to
472: the generic structure and described by a generic presentation. Homogeneity is
473: the first. Since every document in a class corresponds to the same generic
1.1 cvs 474: logical structure, a homogenous presentation for different documents of the
475: same class can be assured by applying the same generic presentation to all
476: documents of the class. Homogeneity of presentation can also be found among
1.2 cvs 477: the entities of a single document: every section heading will be presented in
1.1 cvs 478: the same way, the first line of every paragraph of the same type will have the
1.18 cvs 479: same indentation, etc.</p>
1.30 cvs 480:
481: <p>Another advantage of this approach to presentation is that it facilitates
1.1 cvs 482: changes to the graphical aspect of documents. A change to the generic
483: presentation rules attached to each type of entity will alter the presentation
484: of the entire document, and will do so homogenously. In this case, the
485: internal homogeneity of the class is no longer assured, but the way to control
486: it is simple. It suffices to adopt a single generic presentation for the
1.18 cvs 487: entire class.</p>
1.30 cvs 488:
489: <p>If the presentation of the class does not have to be homogenous, then the
1.1 cvs 490: appearance of the document can be adapted to the way it will be used or to the
491: device used to render it. This quality is sufficient to allow the existence
1.18 cvs 492: of <a name="mulpres">many generic presentations</a> for the same document
1.1 cvs 493: class. By applying one or the other of these presentations to it, the document
494: can be seen under different graphical aspects. It must be emphasized that
495: this type of modification of the presentation is not a change to the document
496: itself (in its specific logical structure or its content), but only in its
1.18 cvs 497: appearance at the time of editing or printing.</p>
498: </div>
1.1 cvs 499:
1.18 cvs 500: <div class="section">
1.30 cvs 501: <h2><a name="sectb24">Document structures and object structures</a></h2>
1.1 cvs 502:
1.30 cvs 503: <p>So far, we have only discussed the global structure of documents and have
504: not considered the contents found in that structure. We could limit ourselves
505: to purely textual contents by assuming that a title or a paragraph contains a
1.1 cvs 506: simple linear text. But this model would be too restrictive. In fact,
507: certain documents contain not only text, but also contain tables, diagrams,
508: photographs, mathematical formulas, and program fragments. The model must
1.18 cvs 509: permit the representation of such <em>objects</em>.</p>
1.30 cvs 510:
511: <p>Just as with the whole of the document, the model takes into account the
1.1 cvs 512: logical structure of objects of this type. Some are clearly structured,
513: others are less so. Logical structure can be recognized in mathematical
514: formulas, in tables, and in certain types of diagrams. On the other hand, it
515: is difficult to define the structure of a photograph or of some drawings. But
516: in any case, it does not seem possible to define one unique structure which
517: can represent every one of these types of objects. The approach taken in the
518: definition of meta-structure and document classes also applies to objects.
519: Object classes can be defined which put together objects of similar type,
1.18 cvs 520: constructed from the same generic logical structure.</p>
1.30 cvs 521:
522: <p>Thus, a mathematical class can be defined and have a generic logical
523: structure associated with it. But even if a single generic structure can
524: represent a sufficient variety of mathematical formulas, for other objects
525: with less rigorous structure, multiple classes must be defined. As for
526: documents, using multiple classes assures that the model can describe the full
527: range of objects to be presented. It also permits the system to support
528: objects which were not initially anticipated. Moreover, this comment applies
529: equally to mathematics: different classes of formulas can be described
530: depending on the domain of mathematics being described.</p>
531:
532: <p>Since objects have the same level of logical representation as documents,
533: they gain the same advantages. In particular, it is possible to define the
1.1 cvs 534: presentation separately from the objects themselves and attach it to the
535: class. Thus, as for documents, objects of the same type have a uniform
536: presentation and the presentation of every object in a given class can be
537: changed simply by changing the generic presentation of the class. Another
538: advantage of using this document model is that the system does not bother the
539: user with the details of presentation, but rather allows the user to
1.18 cvs 540: concentrate on the logical aspect of the document and the objects.</p>
1.30 cvs 541:
542: <p>It is clear that the documents in a class do not necessarily use the same
1.1 cvs 543: classes of objects: one technical report will contain tables while another
544: report will have no tables but will use mathematical formulas. The usable
1.2 cvs 545: object classes are not always mentioned in a limiting way in the generic
546: logical structure of documents. Rather, they can be chosen freely from a
1.18 cvs 547: large set, independent of the document class.</p>
1.30 cvs 548:
549: <p>Thus, the object classes will be made commonplace and usable in every
1.1 cvs 550: document. The notion of ``object'' can be enlarged to include not only
551: non-textual elements, but also certain types of textual elements which can
552: appear in practically every document, whatever their class. Among these
1.2 cvs 553: textual elements, one can mention enumerations, descriptions, examples,
1.18 cvs 554: quotations, even paragraphs.</p>
1.30 cvs 555:
556: <p>Thus, the document model is not a single, general model describing every
557: type of document in one place. Rather, it is a meta-model which can be used
558: to describe many different models each of which represents either a class of
1.1 cvs 559: similar documents or a class of similar objects which every document can
1.18 cvs 560: include.</p>
561: </div>
562: <hr>
563: </div>
1.1 cvs 564:
1.18 cvs 565: <div class="chapter">
566: <h1><a name="sect3">The S language</a></h1>
1.1 cvs 567:
1.18 cvs 568: <div class="section">
1.30 cvs 569: <h2><a name="sectb31">Document meta-structure</a></h2>
1.1 cvs 570:
1.30 cvs 571: <p>Since the concept of meta-structure is well suited to the task of
572: describing documents at a high level of abstraction, this meta-structure must
573: be precisely defined. Toward that end this section first presents the basic
1.1 cvs 574: elements from which documents and structured objects are composed and then
575: specifies the ways in which these basic elements are assembled into structures
1.18 cvs 576: representing complete documents and objects.</p>
1.1 cvs 577:
1.18 cvs 578: <div class="subsection">
1.30 cvs 579: <h3><a name="sectc311">The basic types</a></h3>
1.1 cvs 580:
1.30 cvs 581: <p>At the lowest level of a document's structure, the first atom considered is
1.1 cvs 582: the character. However, since characters are seldom isolated, usually
583: appearing as part of a linear sequence, and in order to reduce the complexity
1.18 cvs 584: of the document structure, <em>character strings</em> are used as atoms and
1.1 cvs 585: consecutive characters belonging to the same structural element are grouped in
1.18 cvs 586: the same character string.</p>
1.30 cvs 587:
588: <p>If the structure of a document is not refined to go down to the level of
1.1 cvs 589: words or phrases, the contents of a simple paragraph can be considered to be a
590: single character string. On the other hand, the title of a chapter, the title
591: of the first section of that chapter, and the text of the first paragraph of
592: that section constitute three different character strings, because they belong
1.18 cvs 593: to distinct structural elements.</p>
1.30 cvs 594:
595: <p>If, instead, a very fine-grained representation for the structure of a
1.1 cvs 596: document is sought, character strings could be defined to contain only a
597: single word, or even just a single character. This is the case, for example,
598: in programs, for which one wants to retain a structure very close to the
1.2 cvs 599: syntax of the programming language. In this case, an assignment statement
1.1 cvs 600: initializing a simple variable to zero would be composed of two structural
601: elements, the identifier of the variable (a short character string) and the
1.18 cvs 602: assigned value (a string of a single character, `0').</p>
1.30 cvs 603:
604: <p>The character string is not the only atom necessary for representing those
1.1 cvs 605: documents that interest us. It suffices for purely textual documents, but as
606: soon as the non-textual objects which we have considered arise, there must be
607: other atoms; the number of objects which are to be represented determines the
1.18 cvs 608: number of types of atoms that are necessary.</p>
1.30 cvs 609:
610: <p>Primitive <em>graphical elements</em> are used for tables and figures of
1.1 cvs 611: different types. These elements are simple geometric shapes like horizontal
612: or vertical lines, which are sufficient for tables, or even oblique lines,
1.2 cvs 613: arrows, rectangles, circles, polygons, and curves for use in figures. From
614: these elements and character strings, graphical objects and tables can be
1.18 cvs 615: constructed.</p>
1.30 cvs 616:
617: <p>Photographs, though having very little structure, must still appear in
1.18 cvs 618: documents. They are supported by <em>picture</em> elements, which are
619: represented as matrices of pixels.</p>
1.30 cvs 620:
621: <p>Finally, mathematical notations require certain elements which are
1.18 cvs 622: simultaneously characters and graphical elements, the <em>symbols</em>. By way
1.2 cvs 623: of example, radicals, integration signs, or even large parentheses are
1.1 cvs 624: examples of this type of atom. The size of each of these symbols is
625: determined by its environment, that is to say, by the expression to which it
1.18 cvs 626: is attached.</p>
1.30 cvs 627:
628: <p>To summarize, the primitive elements which are used in the construction of
1.18 cvs 629: documents and structured objects are:</p>
630: <ul>
1.30 cvs 631: <li>character strings,</li>
632: <li>graphical elements,</li>
633: <li>pictures,</li>
634: <li>and mathematical symbols.</li>
1.18 cvs 635: </ul>
636: </div>
1.1 cvs 637:
1.18 cvs 638: <div class="subsection">
1.30 cvs 639: <h3><a name="sectc312">Constructed elements</a></h3>
640:
641: <p>A document is evidently formed from primitive elements. But the model of
642: Thot also proposes higher level elements. Thus, in a document composed of
643: several chapters, each chapter is an element, and in the chapters each section
644: is also an element, and so on. A document is thus an organized set of
645: elements.</p>
1.1 cvs 646:
1.30 cvs 647: <p>In a document there are different sorts of elements. Each element has a
1.18 cvs 648: <em>type</em> which indicates the role of the element within the document as a
1.1 cvs 649: whole. Thus, we have, for example, the chapter and section types. The
650: document is made up of typed elements: elements of the type chapter and
651: elements of the type section, among others, but also character string elements
652: and graphical elements: the primitive elements are typed elements just as
653: well. At the other extreme, the document itself is also considered to be a
1.18 cvs 654: typed element.</p>
1.30 cvs 655:
656: <p>The important difference between the primitive elements and the other
657: elements of the document is that the primitive elements are atoms (they cannot
658: be decomposed), whereas the others, called <em>constructed elements</em>, are
1.1 cvs 659: composed of other elements, which can either be primitive elements or
660: constructed elements. A constructed element of type chapter (or more simply,
661: ``a chapter'') is composed of sections, which are also constructed elements. A
662: paragraph, a constructed element, can be made up of character strings, which
1.18 cvs 663: are primitive elements, and of equations, which are constructed elements.</p>
1.30 cvs 664:
665: <p>A document is also a constructed element. This is an important point. In
1.1 cvs 666: particular, it allows a document to be treated as part of another document,
667: and conversely, permits a part of a document to be treated as a complete
668: document. Thus, an article presented in a journal is treated by its author as
669: a document in itself, while the editor of the journal considers it to be part
670: of an issue. A table or a figure appearing in a document can be extracted and
671: treated as a complete document, for example to prepare transparencies for a
1.18 cvs 672: conference.</p>
1.30 cvs 673:
674: <p>These thoughts about types and constructed elements apply just as well to
1.1 cvs 675: objects as they do to documents. A table is a constructed element made up of
676: other constructed elements, rows and columns. A row is formed of cells, which
677: are also constructed elements which contain primitive elements (character
1.18 cvs 678: strings) and/or constructed elements like equations.</p>
679: </div>
1.1 cvs 680:
1.18 cvs 681: <div class="subsection">
1.30 cvs 682: <h3><a name="sectc313">Logical structure constructors</a></h3>
1.1 cvs 683:
1.30 cvs 684: <p>Having defined the primitive elements and the constructed elements, it is
685: now time to define the types of organization which allow the building of
1.18 cvs 686: structures. For this, we rely on the notion of the <em>constructor</em>. A
1.1 cvs 687: constructor defines a way of assembling certain elements in a structure. It
688: resides at the level of the meta-structure: it does not describe the existing
689: relations in a given structure, but rather defines how elements are assembled
1.18 cvs 690: to build a structure that conforms to a model.</p>
1.30 cvs 691:
692: <p>In defining the overall organization of documents, the first two
693: constructors considered are the aggregate and the list.</p>
1.1 cvs 694:
1.18 cvs 695: <div class="subsubsection">
1.30 cvs 696: <h4><a name="sectd3131">Aggregate and List</a></h4>
1.1 cvs 697:
1.30 cvs 698: <p>The <em>aggregate</em> constructor is used to define constructed element
699: types which are collections of a given number of other elements. These
700: collections may or may not be ordered. The elements may be either constructed
701: or primitive and are specified by their type. A report (that is, a
702: constructed element of the report type) has an aggregate structure. It is
703: formed from a title, an author's name, an introduction, a body, and a
704: conclusion, making it a collection of five element types. This type of
705: constructor is found in practically every document, and generally at several
706: levels in a document.</p>
707:
708: <p>The <em>list</em> constructor is used to define constructed elements which
709: are ordered sequences of elements (constructed or primitive) having the same
710: type. The minimum and maximum numbers of elements for the sequence can be
711: specified in the list constructor or the number of elements can be left
712: unconstrained. The body of a report is a list of chapters and is typically
713: required to contain a minimum of two chapters (is a chapter useful if it is
714: the only one in the report?) The chapter itself can contain a list of
715: sections, each section containing a list of paragraphs. In the same way as
716: the aggregate, the list is a very frequently used constructor in every type of
717: document. However, these two constructors are not sufficient to describe every
718: document structure; thus other constructors supplement them.</p>
1.18 cvs 719: </div>
1.1 cvs 720:
1.18 cvs 721: <div class="subsubsection">
1.30 cvs 722: <h4><a name="sectd3132">Choice, Schema, and Unit</a></h4>
1.1 cvs 723:
1.30 cvs 724: <p>The <em>choice</em> constructor is used to define the structure of an
725: element type for which one alternative is chosen from several possibilities.
726: Thus, a paragraph can be either a simple text paragraph, or an enumeration, or
727: a citation.</p>
728:
729: <p>The choice constructor indicates the complete list of possible options,
730: which can be too restrictive in certain cases, the paragraph being one such
731: case. Two constructors, <em>unit</em> and <em>schema</em>, address this
1.1 cvs 732: inconvenience. They allow more freedom in the choice of an element type. If
733: a paragraph is defined by a schema constructor, it is possible to put in the
734: place of a paragraph a table, an equation, a drawing or any other object
735: defined by another generic logical structure. It is also possible to define a
736: paragraph as a sequence of units, which could be character strings, symbols,
1.2 cvs 737: or pictures. The choice constructor alone defines a generic logical structure
1.1 cvs 738: that is relatively constrained; in contrast, using units and schemas, a very
1.18 cvs 739: open structure can be defined.</p>
1.30 cvs 740:
741: <p>The <em>schema</em> constructor represents an object defined by a generic
1.18 cvs 742: logical structure chosen freely from among those available.</p>
1.30 cvs 743:
744: <p>The <em>unit</em> constructor represents an element whose type can be
745: either a primitive type or an element type defined as a unit in the generic
746: logical structure of the document, or in another generic logical structure
747: used in the document. Such an element may be used in document objects
748: constructed according to other generic structures.</p>
749:
750: <p>Thus, for example, if a cross-reference to a footnote is defined in the
1.1 cvs 751: generic logical structure ``Article'' as a unit, a table (an object defined by
752: another generic structure) can contain cross-references to footnotes, when
753: they appear in an article. In another type of document, a table defined by
754: the same generic structure can contain other types of elements, depending on
755: the type of document into which the table is inserted. All that is needed is
756: to declare, in the generic structure for tables, that the contents of cells
757: are units. In this way, the generic structure of objects is divided up
758: between different types of documents which are able to adapt themselves to the
1.18 cvs 759: environment into which they are inserted.</p>
760: </div>
1.1 cvs 761:
1.18 cvs 762: <div class="subsubsection">
1.30 cvs 763: <h4><a name="sectd3133">Reference and Inclusion</a></h4>
1.1 cvs 764:
1.30 cvs 765: <p>The <em>reference</em> is used to define document elements that are
1.18 cvs 766: cross-references to other elements, such as a section, a chapter, a
767: bibliographic citation, or a figure. The reference is bi-directional. It can
768: be used to access both the element being cross-referenced and each of the
769: elements which make use of the cross-reference.</p>
1.30 cvs 770:
771: <p>References can be either <em>internal</em> or <em>external</em>. That is,
1.1 cvs 772: they can designate elements which appear in the same document or in another
1.18 cvs 773: document.</p>
1.30 cvs 774:
775: <p>The <em><a name="inclusion">inclusion</a></em> constructor is a special
776: type of reference. Like the reference, it is an internal or external
777: bidirectional link, but it is not a cross-reference. This link represents the
778: ``live'' inclusion of the designated element; it accesses the most recent
779: version of that element and not a ``dead'' copy, fixed in the state in which
780: it was found at the moment the copy was made. As soon as an element is
781: modified, all of its inclusions are automatically brought up to date. It must
782: be noted that, in addition to inclusion, Thot permits the creation of ``dead''
783: copies.</p>
784:
785: <p>There are three types of inclusions: inclusions with full expansion,
1.1 cvs 786: inclusions with partial expansion, and inclusions without expansion. During
787: editing, inclusions without expansion are represented on the screen by the
788: name of the included document, in a special color, while inclusions with
789: expansion (full or partial) are represented by a copy (full or partial) of the
790: included element (also in a special color). The on-screen representation of a
1.18 cvs 791: partial inclusion is a <a href="#sectc3213">``skeleton''</a> image of the
792: included document.</p>
1.30 cvs 793:
794: <p>Inclusion with complete expansion can be used to include parts of the same
1.1 cvs 795: document or of other documents. Thus, it can be either an internal or an
796: external link. It can be used to include certain bibliographic entries of a
797: scientific article in another article, or to copy part of a mathematical
798: formula into another formula of the same document, thus assuring that both
1.18 cvs 799: copies will remain synchronized.</p>
1.30 cvs 800:
801: <p>Inclusion without expansion or with partial expansion is used to include
1.1 cvs 802: complete documents. It is always an external link. It is used primarily to
803: divide very large documents into sub-documents that are easier to manipulate,
804: especially when there are many authors. So, a book can include some chapters,
805: where each chapter is a different document which can be edited separately.
806: When viewing the book on the screen, it might be desirable to see only the
807: titles of the chapters and sections. This can be achieved using inclusion
1.18 cvs 808: with partial expansion.</p>
1.30 cvs 809:
810: <p>During printing, inclusions without expansion or with partial expansion can
811: be represented either as they were shown on the screen or by a complete (and
1.18 cvs 812: up-to-date) copy of the included element or document.</p>
1.30 cvs 813:
814: <p>The inclusion constructor, whatever its type, respects the generic
815: structure: only those elements authorized by the generic structure can be
816: included at a given position in a document.</p>
1.18 cvs 817: </div>
1.1 cvs 818:
1.18 cvs 819: <div class="subsubsection">
1.30 cvs 820: <h4><a name="sectd3134">Mark pairs</a></h4>
1.1 cvs 821:
1.30 cvs 822: <p>It is often useful to delimit certain parts of a document independently
823: from the logical structure. For example, one might wish to attach some
824: information (in the form of an <a href="#sectc315">attribute</a>) or a
825: particular treatment to a group of words or a set of consecutive paragraphs.
826: <em>Mark pairs</em> are used to do this.</p>
827:
828: <p>Mark pairs are elements which are always paired and are terminals in the
1.1 cvs 829: logical structure of the document. Their position in the structure of the
830: document is defined in the generic structure. It is important to note that
1.18 cvs 831: when the terminals of a mark pair are <em>extensions</em> (see the next
832: section), they can be used quite freely.</p>
833: </div>
1.1 cvs 834:
1.18 cvs 835: <div class="subsubsection">
1.30 cvs 836: <h4><a name="sectd3135">Restrictions and Extensions</a></h4>
1.1 cvs 837:
1.30 cvs 838: <p>The primitive types and the constructors presented so far permit the
1.1 cvs 839: definition of the logical structure of documents and objects in a rigorous
840: way. But this definition can be very cumbersome in certain cases, notably
841: when trying to constrain or extend the authorized element types in a
1.18 cvs 842: particular context. <em>Restrictions</em> and <em>extensions</em> are used to
843: cope with these cases.</p>
1.30 cvs 844:
845: <p>A restriction associates with a particular element type <em>A</em>, a list
846: of those element types which elements of type <em>A</em> may not contain, even
847: if the definition of type <em>A</em> and those of its components authorize
848: them otherwise. This simplifies the writing of generic logical structures and
1.1 cvs 849: allows limitations to be placed, when necessary, on the choices offered by the
1.18 cvs 850: schema and unit constructors.</p>
1.30 cvs 851:
852: <p>Extensions are the inverse of restrictions. They identify a list of
853: element types whose presence <em>is</em> permitted, even if its definition and
854: those of its components do not authorize them otherwise.</p>
1.18 cvs 855: </div>
856:
857: <div class="subsubsection">
1.30 cvs 858: <h4><a name="sectd3136">Summary</a></h4>
1.18 cvs 859:
1.30 cvs 860: <p>Thus, four constructors are used to construct a document:</p>
1.18 cvs 861: <ul>
1.30 cvs 862: <li>the aggregate constructor (ordered or not),</li>
863: <li>the list constructor,</li>
864: <li>the choice constructor and its extensions, the unit and schema
865: constructors,</li>
866: <li>the reference constructor and its variant, the inclusion.</li>
867: </ul>
868:
869: <p>These constructors are also sufficient for objects. Thus, these
870: constructors provide a homogenous meta-model which can describe both the
871: organization of the document as a whole and that of the various types of
872: objects which it contains. After presenting the description language for
873: generic structures, we will present several examples which illustrate the
874: appropriateness of the model.</p>
875:
876: <p>The first three constructors (aggregate, list and choice) lead to tree-like
1.1 cvs 877: structures for documents and objects, the objects being simply the subtrees of
878: the tree of a document (or even of other objects' subtrees). The reference
879: constructor introduces other, non-hierarchical, relations which augment those
880: of the tree: when a paragraph makes reference to a chapter or a section, that
881: relation leaves the purely tree-like structure. Moreover, external reference
882: and inclusion constructors permit the establishment of links between different
1.18 cvs 883: documents, thus creating a hypertext structure.</p>
884: </div>
885: </div>
1.1 cvs 886:
1.18 cvs 887: <div class="subsection">
1.30 cvs 888: <h3><a name="sectc314">Associated Elements</a></h3>
1.1 cvs 889:
1.30 cvs 890: <p>Thanks to the list, aggregate and choice constructors, the organization of
891: the document is specified rigorously, using constructed and primitive
892: elements. But a document is made up of more than just its elements; it clearly
893: also contains links between them. There exist elements whose position in the
1.1 cvs 894: document's structure is not determinable. This is notably the case for
895: figures and notes. A figure can be designated at many points in the same
896: document and its place in the physical document can vary over the life of the
897: document without any effect on the meaning or clarity of the document. At one
898: time, it can be placed at the end of the document along with all other
899: figures. At another time, it can appear at the top of the page which follows
900: the first mention of the figure. The figures can be dispersed throughout the
901: document or can be grouped together. The situation is similar for notes,
902: which can be printed at the bottom of the page on which they are mentioned or
903: assembled together at the end of the chapter or even the end of the work. Of
904: course, this brings up questions of the physical position of elements in
905: documents that are broken into pages, but this reflects the structural
906: instability of these elements. They cannot be treated the same way as
907: elements like paragraphs or sections, whose position in the structure is
1.18 cvs 908: directly linked to the semantics of the document.</p>
1.30 cvs 909:
910: <p>Those elements whose position in the structure of the document is not
911: fixed, even though they are definitely part of the document, are called
1.18 cvs 912: <em>associated elements</em>. Associated elements are themselves structures,
1.1 cvs 913: which is to say that their content can be organized logically by the
1.18 cvs 914: constructors from primitive and constructed elements.</p>
1.30 cvs 915:
916: <p>It can happen that the associated elements are totally disconnected from
917: the structure of the document, as in a commentary or appraisal of the entire
918: work. But more often, the associated elements are linked to the content of the
1.1 cvs 919: document by references. This is generally the case for notes and figures,
1.18 cvs 920: among others.</p>
1.30 cvs 921:
922: <p>Thus, associated elements introduce a new use for the reference
923: constructor. It not only serves to create links between elements of the
924: principal structure of the document, but also serves to link the associated
925: elements to the primary structure.</p>
1.18 cvs 926: </div>
1.1 cvs 927:
1.18 cvs 928: <div class="subsection">
1.30 cvs 929: <h3><a name="sectc315">Attributes</a></h3>
1.1 cvs 930:
1.30 cvs 931: <p>There remain logical aspects of documents that are not entirely described
932: by the structure. Certain types of semantic information, which are not stated
1.1 cvs 933: explicitly in the text, must also be taken into account. In particular, such
934: information is shown by typographic effects which do not correspond to a
935: change between structural elements. In fact, certain titles are set in bold
936: or italic or are printed in a different typeface from the rest of the text in
937: order to mark them as structurally distinct. But these same effects
938: frequently appear in the middle of continuous text (e.g. in the interior of a
939: paragraph). In this case, there is no change between structural elements; the
940: effect serves to highlight a word, expression, or phrase. The notion of an
1.18 cvs 941: <em>attribute</em> is used to express this type of information.</p>
1.30 cvs 942:
943: <p>An attribute is a piece of information attached to a structural element
944: which augments the type of the element and clarifies its function in the
945: document. Keywords, foreign language words, and titles of other works can all
946: be represented by character strings with attached attributes. Attributes may
1.1 cvs 947: also be attached to constructed elements. Thus, an attribute indicating the
948: language can be attached to a single word or to a large part of a
1.18 cvs 949: document.</p>
1.30 cvs 950:
951: <p>In fact, an attribute can be any piece of information which is linked to a
1.1 cvs 952: part of a document and which can be used by agents which work on the document.
953: For example, the language in which the document is written determines the set
954: of characters used by an editor or formatter. It also determines the
955: algorithm or hyphenation dictionary to be used. The attribute ``keyword''
956: facilitates the work of an information retrieval system. The attribute
957: ``index word'' allows a formatter to automatically construct an index at the
1.18 cvs 958: end of the document.</p>
1.30 cvs 959:
960: <p>As with the types of constructed elements, the attributes and the values
961: they can take are defined separately in each generic logical structure, not in
962: the meta-model, according to the needs of the document class or the nature of
963: the object.</p>
964:
965: <p>Many types of attributes are offered: numeric, textual, references, and
1.18 cvs 966: enumerations:</p>
967: <ul>
1.30 cvs 968: <li><em>Numeric attributes</em> can take integer values (negative, positive,
969: or null).</li>
970: <li><em>Textual attributes</em> have as their values character strings.</li>
971: <li><em>Reference attributes</em> designate an element of the logical
972: structure.</li>
973: <li><em>Enumeration attributes</em> can take one value from a limited list
974: of possible values, each value being a name.</li>
1.18 cvs 975: </ul>
1.30 cvs 976:
977: <p>In a generic structure, there is a distinction between <em>global
1.18 cvs 978: attributes</em> and <em>local attributes</em>. A global attribute can be
1.1 cvs 979: applied to every element type defined in the generic structure where it is
980: specified. In contrast, a local attribute can only be applied to certain
981: types of elements, even only a single type. The ``language'' attribute
982: presented above is an example of a global attribute. An example of a local
983: attribute is the rank of an author (principal author of the document or
984: secondary author): this attribute can only be applied sensibly to an element
1.18 cvs 985: of the ``author'' type.</p>
1.30 cvs 986:
987: <p>Attributes can be assigned to the elements which make up the document in
988: many different ways. The author can freely and dynamically place them on any
989: part of the document in order to attach supplementary information of his/her
1.18 cvs 990: choice. However, attributes may only be assigned in accordance with the rules
991: of the generic structure; in particular, local attributes can only be assigned
992: to those element types for which they are defined.</p>
1.30 cvs 993:
994: <p>In the generic structure, certain local attributes can be made mandatory
995: for certain element types. In this case, Thot automatically associates the
1.2 cvs 996: attribute with the elements of this type and it requires the user to provide a
1.18 cvs 997: value for this attribute.</p>
1.30 cvs 998:
999: <p>Attributes can also be automatically assigned, with a given value, by every
1.1 cvs 1000: application processing the document in order to systematically add a piece of
1001: information to certain predefined elements of the document. By way of
1002: example, in a report containing a French abstract and an English abstract,
1003: each of the two abstracts is defined as a sequence of paragraphs. The first
1004: abstract has a value of ``French'' for the ``language'' attribute while the
1.18 cvs 1005: second abstract's ``language'' attribute has a value of ``English''.</p>
1.30 cvs 1006:
1007: <p>In the case of mark pairs, attributes are logically associated with the
1008: pair as a whole, but are actually attached to the first mark.</p>
1.18 cvs 1009: </div>
1.1 cvs 1010:
1.18 cvs 1011: <div class="subsection">
1.30 cvs 1012: <h3><a name="sectc316">Discussion of the model</a></h3>
1.1 cvs 1013:
1.30 cvs 1014: <p>The notions of attribute, constructor, structured element, and associated
1.1 cvs 1015: element are used in the definition of generic logical structures of documents
1016: and objects. The problem is to assemble them to form generic structures. In
1017: fact, many types of elements and attributes can be found in a variety of
1018: generic structures. Rather than redefine them for each structure in which
1019: they appear, it is best to share them between structures. The object classes
1020: already fill this sharing function. If a mathematical class is defined, its
1021: formulas can be used in many different document classes, without redefining
1022: the structure of each class. This problem arises not only for the objects
1023: considered here; it also arises for the commonplace textual elements found in
1024: many document classes. This is the reason why the notion of object is so
1025: broad and why paragraphs and enumerations are also considered to be objects.
1026: These object classes not only permit the sharing of the structures of
1.18 cvs 1027: elements, but also of the attributes defined in the generic structures.</p>
1.30 cvs 1028:
1029: <p>Structure, such as that presented here, can appear very rigid, and it is
1.1 cvs 1030: possible to imagine that a document editing system based on this model could
1031: prove very constraining to the user. This is, in fact, a common criticism of
1032: syntax-directed editors. This defect can be avoided with Thot, primarily for
1.18 cvs 1033: three reasons:</p>
1034: <ul>
1.30 cvs 1035: <li>the generic structures are not fixed in the model itself,</li>
1036: <li>the model takes the dynamics of documents into account,</li>
1037: <li>the constructors offer great flexibility.</li>
1.18 cvs 1038: </ul>
1.30 cvs 1039:
1040: <p>When the generic structure of a document is not predefined, but rather is
1.1 cvs 1041: constructed specifically for each document class, it can be carefully adapted
1042: to the current needs. In cases where the generic structure is inadequate for
1043: a particular document of the class, it is always possible either to create a
1044: new class with a generic structure well suited to the new case or to extend
1045: the generic structure of the existing class to take into account the specifics
1046: of the document which poses the problem. These two solutions can also be
1.18 cvs 1047: applied to objects whose structures prove to be poorly designed.</p>
1.30 cvs 1048:
1049: <p>The model is sufficiently flexible to take into account all the phases of
1050: the life of the document. When a generic structure specifies that a report
1051: must contain a title, an abstract, an introduction, at least two chapters, and
1052: a conclusion, this means only that a report, <em>upon completion</em>, will
1053: have to contain all of these elements. When the author begins writing, none
1054: of these elements is present. Thot uses this model. Therefore, it tolerates
1.2 cvs 1055: documents which do not conform strictly to the generic structure of their
1056: class; it also considers the generic logical structure to be a way of helping
1.18 cvs 1057: the user in the construction of a complex document.</p>
1.30 cvs 1058:
1059: <p>In contrast, other applications may reject a document which does not
1060: conform strictly to its generic structure. This is, for example, what is done
1061: by compilers which refuse to generate code for a program which is not
1.1 cvs 1062: syntactically correct. This might also occur when using a document
1.18 cvs 1063: application for a report which does not have an abstract or title.</p>
1.30 cvs 1064:
1065: <p>The constructors of the document model bring a great flexibility to the
1.1 cvs 1066: generic structures. A choice constructor (and even more, a unit or schema
1067: constructor) can represent several, very different elements. The list
1068: constructor permits the addition of more elements of the same type. Used
1069: together, these two constructors permit any series of elements of different
1070: types. Of course, this flexibility can be reduced wherever necessary since a
1071: generic structure can limit the choices or the number of elements in a
1.18 cvs 1072: list.</p>
1.30 cvs 1073:
1074: <p>Another difficulty linked to the use of structure in the document model
1.1 cvs 1075: resides in the choice of the level of the structure. The structure of a
1076: discussion could be extracted from the text itself via linguistic analysis.
1077: Some studies are exploring this approach, but the model of Thot excludes this
1078: type of structure. It only takes into account the logical structure provided
1.18 cvs 1079: explicitly by the author.</p>
1.30 cvs 1080:
1081: <p>However, the level of structure of the model is not imposed. Each generic
1.1 cvs 1082: structure defines its own level of structure, adapted to the document class or
1083: object and to the ways in which it will be processed. If it will only be
1084: edited and printed, a relatively simple structure suffices. If more
1085: specialized processing will be applied to it, the structure must represent the
1086: element types on which this processing must act. By way of example, a simple
1087: structure is sufficient for printing formulas, but a more complex structure is
1088: required to perform symbolic or numeric calculations on the mathematical
1.18 cvs 1089: expressions. The document model of Thot allows both types of structure.</p>
1090: </div>
1091: </div>
1.1 cvs 1092:
1.18 cvs 1093: <div class="section">
1.30 cvs 1094: <h2><a name="sectb32">The definition language for generic structures</a></h2>
1.1 cvs 1095:
1.30 cvs 1096: <p>Generic structures, which form the basis of the document model of Thot, are
1.1 cvs 1097: specified using a special language. This definition language, called S, is
1.18 cvs 1098: described in this section.</p>
1.30 cvs 1099:
1100: <p>Each generic structure, which defines a class of documents or objects, is
1.2 cvs 1101: specified by a file, written in the S language, which is called a
1.18 cvs 1102: <em>structure schema</em>. Structure schemas are compiled into tables, called
1103: structure tables, which are used by Thot and which determine its behavior.</p>
1.1 cvs 1104:
1.18 cvs 1105: <div class="subsection">
1.30 cvs 1106: <h3><a name="sectc321">Writing Conventions</a></h3>
1.1 cvs 1107:
1.30 cvs 1108: <p>The grammar of S, like those of the languages P and T presented later, is
1.1 cvs 1109: described using the meta-language M, derived from the Backus-Naur Form
1.18 cvs 1110: (BNF).</p>
1.30 cvs 1111:
1112: <p>In this meta-language each rule of the grammar is composed of a grammar
1113: symbol followed by an equals sign (`=') and the right part of the rule. The
1114: equals sign plays the same role as the traditional `::=' of BNF: it indicates
1115: that the right part defines the symbol of the left part. In the right
1116: part,</p>
1.18 cvs 1117: <dl>
1.30 cvs 1118: <dt>concatenation</dt>
1119: <dd>is shown by the juxtaposition of symbols;</dd>
1120: <dt>character strings</dt>
1121: <dd>between apostrophes ' represent terminal symbols, that is, keywords in
1122: the language defined. Keywords are written here in upper-case letters,
1.31 cvs 1123: but can be written in any combination of upper and lower-case letters.
1.30 cvs 1124: For example, the keyword <tt>DEFPRES</tt> of S can also be written as
1125: <tt>defpres</tt> or <tt>DefPres</tt>.</dd>
1126: <dt>material between brackets</dt>
1127: <dd>(`[' and `]') is optional;</dd>
1128: <dt>material between angle brackets</dt>
1129: <dd>(`<' and `>') can be repeated many times or omitted;</dd>
1130: <dt>the slash</dt>
1131: <dd>(`/') indicates an alternative, a choice between the options separated
1132: by the slash character;</dd>
1133: <dt>the period</dt>
1134: <dd>marks the end of a rule;</dd>
1135: <dt>text between braces</dt>
1136: <dd>(`{' and `}') is simply a comment.</dd>
1.18 cvs 1137: </dl>
1.30 cvs 1138:
1139: <p>The M meta-language also uses the concepts of identifiers, strings, and
1.18 cvs 1140: integers:</p>
1141: <dl>
1.30 cvs 1142: <dt><tt>NAME</tt></dt>
1143: <dd>represents an identifier, a sequence of letters (upper or lower-case),
1144: digits, and underline characters (`_'), beginning with a letter. Also
1145: considered a letter is the sequence of characters `<tt>\nnn</tt>' where
1146: the letter <tt>n</tt> represents the ISO Latin-1 code of the letter in
1147: octal. It is thus possible to use accented letters in identifiers. The
1148: maximum length of identifiers is fixed by the compiler. It is normally
1149: 31 characters.
1150: <p>Unlike keywords, upper and lower-case letters are distinct in
1151: identifiers. Thus, <tt>Title</tt>, <tt>TITLE</tt>, and <tt>title</tt>
1152: are considered different identifiers.</p>
1153: </dd>
1154: <dt><tt>STRING</tt></dt>
1155: <dd>represents a string. This is a string of characters delimited by
1.31 cvs 1156: apostrophes. If an apostrophe must appear in a string, it is doubled. As
1157: with identifiers, strings can contain characters represented by their
1.30 cvs 1158: octal code (after a backslash). As with apostrophes, if a backslash
1159: must appear in a string, it is doubled.</dd>
1160: <dt><tt>NUMBER</tt></dt>
1161: <dd>represents a positive integer or zero (without a sign), or said
1162: another way, a sequence of decimal digits.</dd>
1.18 cvs 1163: </dl>
1.30 cvs 1164:
1165: <p>The M language can be used to define itself as follows:</p>
1.18 cvs 1166: <pre>{ Any text between braces is a comment. }
1.30 cvs 1167: Grammar = Rule < Rule > 'END' .
1168: { The < and > signs indicate zero }
1.1 cvs 1169: { or more repetitions. }
1170: { END marks the end of the grammar. }
1171: Rule = Ident '=' RightPart '.' .
1172: { The period indicates the end of a rule }
1173: RightPart = RtTerminal / RtIntermed .
1174: { The slash indicates a choice }
1175: RtTerminal ='NAME' / 'STRING' / 'NUMBER' .
1176: { Right part of a terminal rule }
1.30 cvs 1177: RtIntermed = Possibility < '/' Possibility > .
1.1 cvs 1178: { Right part of an intermediate rule }
1.30 cvs 1179: Possibility = ElemOpt < ElemOpt > .
1180: ElemOpt = Element / '[' Element < Element > ']' /
1181: '<' Element < Element > '>' .
1.1 cvs 1182: { Brackets delimit optional parts }
1183: Element = Ident / KeyWord .
1184: Ident = NAME .
1185: { Identifier, sequence of characters }
1186: KeyWord = STRING .
1187: { Character string delimited by apostrophes }
1.18 cvs 1188: END</pre>
1189: </div>
1.1 cvs 1190:
1.18 cvs 1191: <div class="subsection">
1.30 cvs 1192: <h3><a name="sectc322">Extension schemas</a></h3>
1.1 cvs 1193:
1.30 cvs 1194: <p>A structure schema defines the generic logical structure of a class of
1.1 cvs 1195: documents or objects, independent of the operations which can be performed on
1196: the documents. However, certain applications may require particular
1197: information to be represented by the structure for the documents that they
1198: operate on. Thus a document version manager will need to indicate in the
1199: document the parts which belong to one version or another. An indexing system
1200: will add highly-structured index tables as well as the links between these
1.18 cvs 1201: tables and the rest of the document.</p>
1.30 cvs 1202:
1203: <p>Thus, many applications need to extend the generic structure of the
1204: documents on which they operate to introduce new attributes, associated
1205: elements or element types. These additions are specific to each application
1206: and must be able to be applied to any generic structure: users will want to
1207: manage versions or construct indices for many types of documents. Extension
1208: schemas fulfill this role: they define attributes, elements, associated
1209: elements, units, etc., but they can only be used jointly with a structure
1210: schema that they complete. Otherwise, structure schemas can always be used
1211: without these extensions when the corresponding applications are not
1212: available.</p>
1.18 cvs 1213: </div>
1.1 cvs 1214:
1.18 cvs 1215: <div class="subsection">
1.30 cvs 1216: <h3><a name="sectc323">The general organization of structure schemas</a></h3>
1.1 cvs 1217:
1.30 cvs 1218: <p>Every structure schema begins with the keyword <tt>STRUCTURE</tt> and ends
1.18 cvs 1219: with the keyword <tt>END</tt>. The keyword <tt>STRUCTURE</tt> is followed by
1220: the keyword <tt>EXTENSION</tt> in the case where the schema defines an
1.1 cvs 1221: extension, then by the name of the generic structure which the schema defines
1222: (the name of the document or object class). The name of the structure is
1.18 cvs 1223: followed by a semicolon.</p>
1.30 cvs 1224:
1225: <p>In the case of a complete schema (that is, a schema which is not an
1.1 cvs 1226: extension), the definition of the name of the structure is followed by the
1227: declarations of the default presentation schema, the global attributes, the
1.34 cvs 1228: structure rules, the associated elements, the units, the skeleton elements and
1229: the exceptions. Only the definition of the structure rules is required. Each
1230: series of declarations begins with a keyword: <tt>DEFPRES</tt>, <tt>ATTR</tt>,
1231: <tt>STRUCT</tt>, <tt>ASSOC</tt>, <tt>UNITS</tt>, <tt>EXPORT</tt>,
1232: <tt>EXCEPT</tt>.</p>
1233:
1234: <p>In the case of an extension schema, there are no skeleton elements and the
1235: <tt>STRUCT</tt> section is optional, while that section is required in a
1236: schema that is not an extension. On the other hand, extension schemas can
1237: contain an <tt>EXTENS</tt> section, which must not appear in a schema which is
1238: not an extension; this section defines the complements to attach to the rules
1239: found in the schema to which the extension will be added. The sections
1240: <tt>ATTR</tt>, <tt>STRUCT</tt>, <tt>ASSOC</tt>, and <tt>UNITS</tt> define new
1241: attributes, new elements, new associated elements, and new units which add
1242: their definitions to the principal schema.</p>
1.18 cvs 1243: <pre> StructSchema ='STRUCTURE' ElemID ';'
1.1 cvs 1244: 'DEFPRES' PresID ';'
1245: [ 'ATTR' AttrSeq ]
1246: 'STRUCT' RulesSeq
1247: [ 'ASSOC' RulesSeq ]
1248: [ 'UNITS' RulesSeq ]
1249: [ 'EXPORT' SkeletonSeq ]
1250: [ 'EXCEPT' ExceptSeq ]
1251: 'END' .
1.18 cvs 1252: ElemID = NAME .</pre>
1.30 cvs 1253:
1254: <p>or</p>
1.18 cvs 1255: <pre> ExtensSchema ='STRUCTURE' 'EXTENSION' ElemID ';'
1.1 cvs 1256: 'DEFPRES' PresID ';'
1257: [ 'ATTR' AttrSeq ]
1258: [ 'STRUCT' RulesSeq ]
1259: [ 'EXTENS' ExtensRuleSeq ]
1260: [ 'ASSOC' RulesSeq ]
1261: [ 'UNITS' RulesSeq ]
1262: [ 'EXCEPT' ExceptSeq ]
1263: 'END' .
1.18 cvs 1264: ElemID = NAME .</pre>
1265: </div>
1.1 cvs 1266:
1.18 cvs 1267: <div class="subsection">
1.30 cvs 1268: <h3><a name="sectc324">The default presentation</a></h3>
1.1 cvs 1269:
1.30 cvs 1270: <p>It was shown <a href="#mulpres">above</a> that many different presentations
1.1 cvs 1271: are possible for documents and objects of the same class. The structure
1.18 cvs 1272: schema defines a preferred presentation for the class, called the <em>default
1273: presentation</em>. Like generic structures, presentations are described by
1274: programs, called <em>presentation schemas</em>, which are written in a
1275: specific language, P, presented <a href="#sectb42">later</a> in this document.
1276: The name appearing after the keyword <tt>DEFPRES</tt> is the name of the
1.2 cvs 1277: default presentation schema. When a new document is created, Thot will use
1278: this presentation schema by default, but the user remains free to choose
1.18 cvs 1279: another if s/he wishes.</p>
1280: <pre> PresID = NAME .</pre>
1281: </div>
1.1 cvs 1282:
1.18 cvs 1283: <div class="subsection">
1.30 cvs 1284: <h3><a name="sectc325">Global Attributes</a></h3>
1.1 cvs 1285:
1.30 cvs 1286: <p>If the generic structure includes global attributes of its own, they are
1.18 cvs 1287: declared after the keyword <tt>ATTR</tt>. Each global attribute is defined by
1.1 cvs 1288: its name, followed by an equals sign and the definition of its type. The
1.18 cvs 1289: declaration of a global attribute is terminated by a semi-colon.</p>
1.30 cvs 1290:
1291: <p>For attributes of the numeric, textual, or reference types, the type is
1.18 cvs 1292: indicated by a keyword, <tt>INTEGER</tt>, <tt>TEXT</tt>, or <tt>REFERENCE</tt>
1293: respectively.</p>
1.30 cvs 1294:
1295: <p>In the case of a reference attribute, the keyword <tt>REFERENCE</tt> is
1.1 cvs 1296: followed by the type of the referenced element in parentheses. It can refer
1.18 cvs 1297: to any type at all, specified by using the keyword <tt>ANY</tt>, or to a
1.1 cvs 1298: specific type. In the latter case, the element type designated by the
1.18 cvs 1299: reference can be defined either in the <a href="#sectc327"><tt>STRUCT</tt>
1300: section</a> of the same structure schema or in the <tt>STRUCT</tt> section of
1.1 cvs 1301: another structure schema. When the type is defined in another schema, the
1302: element type is followed by the name of the structure schema (within
1303: parentheses) in which it is defined. The name of the designated element type
1.18 cvs 1304: can be preceded by the keyword <tt>First</tt> or <tt>Second</tt>, but only in
1305: the case where the type is defined as <a href="#sectd3285">a pair</a>. These
1.1 cvs 1306: keywords indicate whether the attribute must designate the first mark of the
1307: pair or the second. If the reference refers to a pair and neither of these
1.18 cvs 1308: two keywords is present, then the first mark is used.</p>
1.30 cvs 1309:
1310: <p>In the case of an enumeration attribute, the equals sign is followed by the
1.1 cvs 1311: list of names representing the possible values of the attribute, the names
1312: being separated from each other by commas. An enumeration attribute has at
1313: least one possible value; the maximum number of values is defined by the
1.18 cvs 1314: compiler for the S language.</p>
1.30 cvs 1315: <pre> AttrSeq = Attribute < Attribute > .
1.1 cvs 1316: Attribute = AttrID '=' AttrType ';' .
1317: AttrType = 'INTEGER' / 'TEXT' /
1318: 'REFERENCE' '(' RefType ')' /
1319: ValueSeq .
1320: RefType = 'ANY' / [ FirstSec ] ElemID [ ExtStruct ] .
1321: FirstSec = 'First' / 'Second' .
1322: ExtStruct = '(' ElemID ')' .
1.30 cvs 1323: ValueSeq = AttrVal < ',' AttrVal > .
1.1 cvs 1324: AttrID = NAME .
1.18 cvs 1325: AttrVal = NAME .</pre>
1.30 cvs 1326:
1327: <p>There is a predefined global text attribute, the <em>language</em>, which
1328: is automatically added to every Thot structure schema. This attribute allows
1.2 cvs 1329: Thot to perform certain actions, such as hyphenation and spell-checking, which
1330: cannot be performed without knowing the language in which each part of the
1331: document is written. This attribute can be used just like any explicitly
1.18 cvs 1332: declared attribute: the system acts as if every structure schema contains</p>
1333: <pre>ATTR
1334: Language = TEXT;</pre>
1.30 cvs 1335:
1.18 cvs 1336: <blockquote class="example">
1.30 cvs 1337: <p><strong>Example:</strong></p>
1338:
1339: <p>The following specification defines the global enumeration attribute
1340: WordType.</p>
1341: <pre>ATTR
1.18 cvs 1342: WordType = Definition, IndexWord, DocumentTitle;</pre>
1343: </blockquote>
1344: </div>
1.1 cvs 1345:
1.18 cvs 1346: <div class="subsection">
1.30 cvs 1347: <h3><a name="sectc327">Structured elements</a></h3>
1.1 cvs 1348:
1.30 cvs 1349: <p>The rules for defining structured elements are required, except in an
1.1 cvs 1350: extension schema: they constitute the core of a structure schema, since they
1351: define the structure of the different types of elements that occur in a
1.18 cvs 1352: document or object of the class defined by the schema.</p>
1.30 cvs 1353:
1354: <p>The first structure rule after the keyword <tt>STRUCT</tt> must define the
1.1 cvs 1355: structure of the class whose name appears in the first instruction
1.18 cvs 1356: (<tt>STRUCTURE</tt>) of the schema. This is the root rule of the schema,
1357: defining the root of the document tree or object tree.</p>
1.30 cvs 1358:
1359: <p>The remaining rules may be placed in any order, since the language permits
1360: the definition of element types before or after their use, or even in the same
1.1 cvs 1361: instruction in which they are used. This last case allows the definition of
1.18 cvs 1362: recursive structures.</p>
1.30 cvs 1363:
1364: <p>Each rule is composed of a name (the name of the element type whose
1365: structure is being defined) followed by an equals sign and a structure
1366: definition.</p>
1367:
1368: <p>If any local attributes are associated with the element type defined by the
1.2 cvs 1369: rule, they appear between parentheses after the type name and before the
1.18 cvs 1370: equals sign. The parentheses contain, first, the keyword <tt>ATTR</tt>, then
1.2 cvs 1371: the list of local attributes, separated by commas. Each local attribute is
1372: composed of the name of the attribute followed by an equals sign and the
1.18 cvs 1373: definition of the attribute's type, just as in the definition of <a
1374: href="#sectc325">global attributes</a>. The name of the attribute can be
1.2 cvs 1375: preceded by an exclamation point to indicate that the attribute must always be
1376: present for this element type. The same attribute, identified by its name,
1377: can be defined as a local attribute for multiple element types. In this
1378: case, the equals sign and definition of the attribute type need only appear in
1379: the first occurrence of the attribute. It should be noted that global
1.18 cvs 1380: attributes cannot also be defined as local attributes.</p>
1.30 cvs 1381:
1382: <p>If any <a href="#sectd3135">extensions</a> are defined for this element
1383: type, a plus sign follows the structure definition and the names of the
1384: extension element types appear between parentheses after the plus. If there
1385: are multiple extensions, they are separated by commas. These types can either
1386: be defined in the same schema, defined in other schemas, or they may be base
1.18 cvs 1387: types identified by the keywords <tt>TEXT</tt>, <tt>GRAPHICS</tt>,
1388: <tt>SYMBOL</tt>, or <tt>PICTURE</tt>.</p>
1.30 cvs 1389:
1390: <p><a href="#sectd3135">Restrictions</a> are indicated in the same manner as
1.18 cvs 1391: extensions, but they are introduced by a minus sign and they come after the
1392: extensions, or if there are no extensions, after the structure definition.</p>
1.30 cvs 1393:
1394: <p>If the values of attributes must be attached systematically to this element
1.18 cvs 1395: type, they are introduced by the keyword <tt>WITH</tt> and declared in the
1.1 cvs 1396: form of a list of fixed-value attributes. When such definitions of fixed
1.18 cvs 1397: attribute values appear, they are always the last part of the rule.</p>
1.30 cvs 1398:
1399: <p>The rule is terminated by a semicolon.</p>
1400: <pre> RuleSeq = Rule < Rule > .
1.1 cvs 1401: Rule = ElemID [ LocAttrSeq ] '=' DefWithAttr ';'.
1.30 cvs 1402: LocAttrSeq = '(' 'ATTR' LocAttr < ';' LocAttr > ')' .
1.1 cvs 1403: LocAttr = [ '!' ] AttrID [ '=' AttrType ] .
1404: DefWithAttr = Definition
1405: [ '+' '(' ExtensionSeq ')' ]
1406: [ '-' '(' RestrictSeq ')' ]
1407: [ 'WITH' FixedAttrSeq ] .
1.30 cvs 1408: ExtensionSeq = ExtensionElem < ',' ExtensionElem > .
1.1 cvs 1409: ExtensionElem = ElemID / 'TEXT' / 'GRAPHICS' /
1410: 'SYMBOL' / 'PICTURE' .
1.30 cvs 1411: RestrictSeq = RestrictElem < ',' RestrictElem > .
1.1 cvs 1412: RestrictElem = ElemID / 'TEXT' / 'GRAPHICS' /
1.18 cvs 1413: 'SYMBOL' / 'PICTURE' .</pre>
1.30 cvs 1414:
1415: <p>The list of fixed-value attributes is composed of a sequence of
1.1 cvs 1416: attribute-value pairs separated by commas. Each pair contains the name of the
1417: attribute and the fixed value for this element type, the two being separated
1418: by an equals sign. If the sign is preceded by a question mark the given value
1419: is only an initial value that may be modified later rather than a value fixed
1420: for all time. Reference attributes are an exception to this norm. They
1421: cannot be assigned a fixed value, but when the name of such an attribute
1422: appears this indicates that this element type must have a valid value for the
1.2 cvs 1423: attribute. For the other attribute types, the fixed value is indicated by a
1.1 cvs 1424: signed integer (numeric attributes), a character string between apostrophes
1.18 cvs 1425: (textual attributes) or the name of a value (enumeration attributes).</p>
1.30 cvs 1426:
1427: <p>Fixed-value attributes can either be <a href="#sectc325">global</a> or
1428: local to the element type for which they are fixed, but they must be declared
1429: before they are used.</p>
1430: <pre> FixedAttrSeq = FixedAttr < ',' FixedAttr > .
1.1 cvs 1431: FixedAttr = AttrID [ FixedOrModifVal ] .
1432: FixedOrModifVal = [ '?' ] '=' FixedValue .
1433: FixedValue = [ '-' ] NumValue / TextVal / AttrVal .
1434: NumValue = NUMBER .
1.18 cvs 1435: TextVal = STRING .</pre>
1436: </div>
1.1 cvs 1437:
1.18 cvs 1438: <div class="subsection">
1.30 cvs 1439: <h3><a name="sectc328">Structure definitions</a></h3>
1.1 cvs 1440:
1.30 cvs 1441: <p>The structure of an element type can be a simple base type or a constructed
1.18 cvs 1442: type.</p>
1.30 cvs 1443:
1444: <p>For constructed types, it is frequently the case that similar structures
1.1 cvs 1445: appear in many places in a document. For example the contents of the
1446: abstract, of the introduction, and of a section can have the same structure,
1447: that of a sequence of paragraphs. In this case, a single, common structure
1448: can be defined (the paragraph sequence in this example), and the schema is
1449: written to indicate that each element type possesses this structure, as
1.18 cvs 1450: follows:</p>
1451: <pre> Abstract = Paragraph_sequence;
1.1 cvs 1452: Introduction = Paragraph_sequence;
1.18 cvs 1453: Section_contents = Paragraph_sequence;</pre>
1.30 cvs 1454:
1455: <p>The equals sign means ``has the same structure as''.</p>
1456:
1457: <p>If the element type defined is a simple base type, this is indicated by one
1458: of the keywords <tt>TEXT</tt>, <tt>GRAPHICS</tt>, <tt>SYMBOL</tt>, or
1.18 cvs 1459: <tt>PICTURE</tt>. If some local attributes must be associated with a base
1.1 cvs 1460: type, the keyword of the base type is followed by the declaration of the local
1.18 cvs 1461: attributes using the syntax <a href="#sectc327">presented above.</a></p>
1.30 cvs 1462:
1463: <p>In the case of an open choice, the type is indicated by the keyword
1.18 cvs 1464: <tt>UNIT</tt> for units or the keyword <tt>NATURE</tt> for objects having a
1465: structure defined by any other schema.</p>
1.30 cvs 1466:
1467: <p>A unit represents one of the two following categories:</p>
1.18 cvs 1468: <ul>
1.30 cvs 1469: <li>a base type: text, graphical element, symbol, picture,</li>
1470: <li>an element whose type is chosen from among the types defined as units in
1471: the <tt>UNITS</tt> section of the document's structure schema. It can
1472: also be chosen from among the types defined as <a
1473: href="#sectd3132">units</a> in the <a href="#sectc3212"><tt>UNITS</tt>
1474: section</a> of the structure schemas that defines the ancestors of the
1475: element to which the rule is applied.</li>
1.18 cvs 1476: </ul>
1.30 cvs 1477:
1478: <p>Before the creation of an element defined as a unit, Thot asks the user to
1.18 cvs 1479: choose between the categories of elements.</p>
1.30 cvs 1480:
1481: <p>Thus, the contents of a paragraph can be specified as a sequence of units,
1.1 cvs 1482: which will permit the inclusion in the paragraphs of character strings,
1483: symbols, and various elements, such as cross-references, if these are defined
1.18 cvs 1484: as units.</p>
1.30 cvs 1485:
1486: <p>A schema object (keyword <tt>NATURE</tt>) represents an object defined by a
1.1 cvs 1487: structure schema freely chosen from among the available schemas; in the case
1488: the element type is defined by the first rule (the root rule) of the chosen
1.18 cvs 1489: schema.</p>
1.30 cvs 1490:
1491: <p>If the element type defined is a constructed type, the list, aggregate,
1.1 cvs 1492: choice, and reference constructors are used. In this case the definition
1493: begins with a keyword identifying the constructor. This keyword is followed
1.18 cvs 1494: by a syntax specific to each constructor.</p>
1.30 cvs 1495:
1496: <p>The local attribute definitions appear after the name of the element type
1.18 cvs 1497: being defined, if this element type has <a href="#sectc327">local
1498: attributes</a>.</p>
1499: <pre> Definition = BaseType [ LocAttrSeq ] / Constr / Element .
1.1 cvs 1500: BaseType = 'TEXT' / 'GRAPHICS' / 'SYMBOL' / 'PICTURE' /
1501: 'UNIT' / 'NATURE' .
1502: Element = ElemID [ ExtOrDef ] .
1503: ExtOrDef = 'EXTERN' / 'INCLUDED' /
1504: [ LocAttrSeq ] '=' Definition .
1505: Constr = 'LIST' [ '[' min '..' max ']' ] 'OF'
1506: '(' DefWithAttr ')' /
1507: 'BEGIN' DefOptSeq 'END' /
1508: 'AGGREGATE' DefOptSeq 'END' /
1509: 'CASE' 'OF' DefSeq 'END' /
1510: 'REFERENCE' '(' RefType ')' /
1.18 cvs 1511: 'PAIR' .</pre>
1.1 cvs 1512:
1.18 cvs 1513: <div class="subsubsection">
1.30 cvs 1514: <h4><a name="sectd3281">List</a></h4>
1.1 cvs 1515:
1.30 cvs 1516: <p>The list constructor permits the definition of an element type composed of
1517: a list of elements, all of the same type. A list definition begins with the
1.18 cvs 1518: <tt>LIST</tt> keyword followed by an optional range, the keyword <tt>OF</tt>,
1.1 cvs 1519: and the definition, between parentheses, of the element type which must
1520: compose the list. The optional range is composed of the minimum and maximum
1521: number of elements for the list separated by two periods and enclosed by
1522: brackets. If the range is not present, the number of list elements is
1523: unconstrained. When only one of the two bounds of the range is unconstrained,
1524: it is represented by a star ('*') character. Even when both bounds are
1.18 cvs 1525: unconstrained, they can be specified by <tt>[*..*]</tt>, but it is simpler not
1526: to specify any bound.</p>
1527: <pre> 'LIST' [ '[' min '..' max ']' ]
1.1 cvs 1528: 'OF' '(' DefWithAttr ')'
1529: min = Integer / '*' .
1530: max = Integer / '*' .
1.18 cvs 1531: Integer = NUMBER .</pre>
1.30 cvs 1532:
1533: <p>Before the document is edited, Thot creates the minimum number of elements
1534: for the list. If no minimum was given, it creates a single element. If a
1535: maximum number of elements is given and that number is attained, the editor
1536: refuses to create new elements for the list.</p>
1537:
1538: <blockquote class="example">
1539: <p><strong>Example:</strong></p>
1540:
1541: <p>The following two instructions define the body of a document as a
1542: sequence of at least two chapters and the contents of a section as a
1543: sequence of paragraphs. A single paragraph can be the entire contents of a
1544: section.</p>
1545: <pre>Body = LIST [2..*] OF (Chapter);
1.18 cvs 1546: Section_contents = LIST OF (Paragraph);</pre>
1547: </blockquote>
1548: </div>
1.1 cvs 1549:
1.18 cvs 1550: <div class="subsubsection">
1.30 cvs 1551: <h4><a name="sectd3282">Aggregate</a></h4>
1.1 cvs 1552:
1.30 cvs 1553: <p>The aggregate constructor is used to define an element type as a collection
1554: of sub-elements, each having a fixed type. The collection may be ordered or
1.1 cvs 1555: unordered. The elements composing the collection are called
1.18 cvs 1556: <em>components</em>. In the definition of an aggregate, a keyword indicates
1557: whether or not the aggregate is ordered: <tt>BEGIN</tt> for an ordered
1558: aggregate, <tt>AGGREGATE</tt> for an unordered aggregate. This keyword is
1.1 cvs 1559: followed by the list of component type definitions which is terminated by the
1.18 cvs 1560: <tt>END</tt> keyword. The component type definitions are separated by
1561: commas.</p>
1.30 cvs 1562:
1563: <p>Before creating an aggregate, the Thot editor creates all the aggregate's
1.1 cvs 1564: components in the order they appear in the structure schema, even for
1565: unordered aggregates. However, unlike ordered aggregates, the components of
1566: an unordered aggregate may be rearranged using operations of the Thot editor.
1567: The exceptions to the rule are any components whose name was preceded by a
1568: question mark character ('?'). These components, which are optional, can be
1569: created by explicit request, possibly at the time the aggregate is created,
1.18 cvs 1570: but they are not created automatically <em>prior</em> to the creation of the
1571: aggregate.</p>
1572: <pre> 'BEGIN' DefOptSeq 'END'
1.30 cvs 1573: DefOptSeq = DefOpt ';' < DefOpt ';' > .
1.18 cvs 1574: DefOpt = [ '?' ] DefWithAttr .</pre>
1.30 cvs 1575:
1.18 cvs 1576: <blockquote class="example">
1.30 cvs 1577: <p><strong>Example:</strong></p>
1578:
1579: <p>In a bilingual document, each paragraph has an English version and a
1580: French version. In certain cases, the translator wants to add a marginal
1581: note, but this note is present in very few paragraphs. Thus, it must not be
1582: created systematically for every paragraph. A bilingual paragraph of this
1583: type is declared:</p>
1584: <pre>Bilingual_paragraph = BEGIN
1.1 cvs 1585: French_paragraph = TEXT;
1586: English_paragraph = TEXT;
1587: ? Note = TEXT;
1.18 cvs 1588: END;</pre>
1589: </blockquote>
1590: </div>
1.1 cvs 1591:
1.18 cvs 1592: <div class="subsubsection">
1.30 cvs 1593: <h4><a name="sectd3283">Choice</a></h4>
1.1 cvs 1594:
1.30 cvs 1595: <p>The choice constructor permits the definition of an element type which is
1.18 cvs 1596: chosen from among a set of possible types. The keywords <tt>CASE</tt> and
1597: <tt>OF</tt> are followed by a list of definitions of possible types, which are
1598: separated by semicolons and terminated by the <tt>END</tt> keyword.</p>
1599: <pre> 'CASE' 'OF' DefSeq 'END'
1.30 cvs 1600: DefSeq = DefWithAttr ';' < DefWithAttr ';' > .</pre>
1601:
1602: <p>Before the creation of an element defined as a choice, the Thot editor
1.1 cvs 1603: presents the list of possible types for the element to the user. The user has
1.18 cvs 1604: only to select the element type that s/he wants to create from this list.</p>
1.30 cvs 1605:
1606: <p>The order of the type declarations is important. It determines the order
1607: of the list presented to the user before the creation of the element. Also,
1608: when a Choice element is being created automatically, the first type in the
1609: list is used. In fact, using the Thot editor, when an empty Choice element is
1.1 cvs 1610: selected, it is possible to select this element and to enter its text from
1611: keyboard. In this case, the editor uses the first element type which can
1.18 cvs 1612: contain an atom of the character string type.</p>
1.30 cvs 1613:
1614: <p>The two special cases of the choice constructor, the <a
1.18 cvs 1615: href="#sectc328"><em>schema</em></a> and the <a
1616: href="#sectc3212"><em>unit</em></a> are discussed elsewhere.</p>
1.30 cvs 1617:
1.18 cvs 1618: <blockquote class="example">
1.30 cvs 1619: <p><strong>Example:</strong></p>
1620:
1621: <p>It is common in documents to treat a variety of objects as if they were
1622: ordinary paragraphs. Thus, a ``Paragraph'' might actually be composed of a
1623: block of text (an ordinary paragraph), or a mathematical formula whose
1624: structure is defined by another structure schema named Math, or a table,
1625: also defined by another structure schema. Here is a definition of such a
1626: paragraph:</p>
1627: <pre>Paragraph = CASE OF
1.1 cvs 1628: Simple_text = TEXT;
1629: Formula = Math;
1630: Table_para = Table;
1.18 cvs 1631: END;</pre>
1632: </blockquote>
1633: </div>
1.1 cvs 1634:
1.18 cvs 1635: <div class="subsubsection">
1.30 cvs 1636: <h4><a name="sectd3284">Reference</a></h4>
1.1 cvs 1637:
1.30 cvs 1638: <p>Like all elements in Thot, references are typed. An element type defined
1639: as a reference is a cross-reference to an element of some other given type.
1640: The keyword <tt>REFERENCE</tt> is followed by the name of a type enclosed in
1.1 cvs 1641: parentheses. When the type which is being cross-referenced is defined in
1642: another structure schema, the type name is itself followed by the name of the
1.18 cvs 1643: external structure schema in which it is defined.</p>
1.30 cvs 1644:
1645: <p>When the designated element type is a <a href="#sectd3285">mark pair</a>,
1646: it can be preceded by a <tt>FIRST</tt> or <tt>SECOND</tt> keyword. These
1.18 cvs 1647: keywords indicate whether the reference points to the first or second mark of
1648: the pair. If the reference points to a pair and neither of these two keywords
1649: is present, the reference is considered to point to the first mark of the
1650: pair.</p>
1.30 cvs 1651:
1652: <p>There is an exception to the principle of typed references: it is possible
1653: to define a reference which designates an element of any type, which can
1654: either be in the same document or another document. In this case, it suffices
1655: to put the keyword <tt>ANY</tt> in the parentheses which indicate the
1656: referenced element type.</p>
1.18 cvs 1657: <pre> 'REFERENCE' '(' RefType ')'
1658: RefType = 'ANY' / [ FirstSec ] ElemID [ ExtStruct ] .</pre>
1.30 cvs 1659:
1660: <p>When defining an inclusion, the <tt>REFERENCE</tt> keyword is not used.
1.1 cvs 1661: Inclusions with complete expansion are not declared as such in the structure
1662: schemas, since any element defined in a structure schema can be replaced by an
1663: element of the same type. Instead, inclusions without expansion or with
1664: partial expansion must be declared explicitly whenever they will include a
1665: complete object ( and not a part of an object). In this case, the object type
1666: to be included (that is, the name of its structure schema) is followed by a
1.18 cvs 1667: keyword: <tt>EXTERN</tt> for inclusion without expansion and <tt>INCLUDED</tt>
1668: for partial expansion.</p>
1.30 cvs 1669:
1670: <p>Before creating a cross-reference or an inclusion, the Thot editor asks the
1.1 cvs 1671: user to choose, from the document images displayed, the referenced or included
1.18 cvs 1672: element.</p>
1.30 cvs 1673:
1.18 cvs 1674: <blockquote class="example">
1.30 cvs 1675: <p><strong>Example:</strong></p>
1676:
1677: <p>If the types Note and Section are defined in the Article structure
1678: schema, it is possible to define, in the same structure schema, a reference
1679: to a note and a reference to a section in this manner:</p>
1680: <pre>Ref_note = REFERENCE (Note);
1.18 cvs 1681: Ref_section = REFERENCE (Section);</pre>
1.30 cvs 1682:
1683: <p>It is also possible to define the generic structure of a collection of
1684: articles, which include (with partial expansion) objects of the Article
1685: class and which possess an introduction which may include cross-references
1686: to sections of the included articles. In the Collection structure schema,
1687: the definitions are:</p>
1688: <pre>Collection = BEGIN
1.6 cvs 1689: Collection_title = TEXT;
1690: Introduction = LIST OF (Elem = CASE OF
1.1 cvs 1691: TEXT;
1692: Ref_sect;
1693: END);
1.6 cvs 1694: Body = LIST OF (Article INCLUDED);
1695: END;
1.18 cvs 1696: Ref_sect = REFERENCE (Section (Article));</pre>
1.30 cvs 1697:
1698: <p>Here we define a Folder document class which has a title and includes
1699: documents of different types, particularly Folders:</p>
1700: <pre>Folder = BEGIN
1.6 cvs 1701: Folder_title = TEXT;
1702: Folder_contents = LIST OF (Document);
1703: END;
1.1 cvs 1704:
1705: Document = CASE OF
1706: Article EXTERN;
1707: Collection EXTERN;
1708: Folder EXTERN;
1.18 cvs 1709: END;</pre>
1.30 cvs 1710:
1711: <p>Under this definition, Folder represents either an aggregate which
1712: contains a folder title and the list of included documents or an included
1713: folder. To resolve this ambiguity, in the P language, the placement of a
1714: star character in front of the type name (here, Folder) indicates an
1715: included document.</p>
1.18 cvs 1716: </blockquote>
1717: </div>
1.1 cvs 1718:
1.18 cvs 1719: <div class="subsubsection">
1.30 cvs 1720: <h4><a name="sectd3285">Mark pairs</a></h4>
1.1 cvs 1721:
1.30 cvs 1722: <p>Like other elements, mark pairs are typed. The two marks of the pair have
1723: the same type, but there exist two predefined subtypes which apply to all mark
1.18 cvs 1724: pairs: the first mark of the pair (called <tt>First</tt> in the P and T
1725: languages) and the second mark (called <tt>Second</tt>).</p>
1.30 cvs 1726:
1727: <p>In the S language, a mark pair is noted simply by the <tt>PAIR</tt>
1.18 cvs 1728: keyword.</p>
1.30 cvs 1729:
1730: <p>In the Thot editor, marks are always moved or destroyed together. The two
1.1 cvs 1731: marks of a pair have the same identifier, unique within the document, which
1.18 cvs 1732: permits intertwining mark pairs without risk of ambiguity.</p>
1733: </div>
1734: </div>
1.1 cvs 1735:
1.18 cvs 1736: <div class="subsection">
1.30 cvs 1737: <h3><a name="sectc329">Imports</a></h3>
1.1 cvs 1738:
1.30 cvs 1739: <p>Because of schema constructors, it is possible, before editing a document,
1740: to use classes defined by other structure schemas whenever they are needed. It
1741: is also possible to assign specific document classes to certain element types.
1742: In this case, these classes are simply designated by their name. In fact, if
1743: a type name is not defined in the structure schema, it is assumed that it
1.18 cvs 1744: specifies a structure defined by another structure schema.</p>
1.30 cvs 1745:
1.18 cvs 1746: <blockquote class="example">
1.30 cvs 1747: <p><strong>Example:</strong></p>
1748:
1749: <p>If the types Math and Table don't appear in the left part of a structure
1750: rule in the schema, the following two rules indicate that a formula has the
1751: structure of an object defined by the structure schema Math and that a table
1752: element has the structure of an object defined by the Table schema.</p>
1753: <pre>Formula = Math;
1.18 cvs 1754: Table_elem = Table;</pre>
1755: </blockquote>
1756: </div>
1757:
1758: <div class="subsection">
1.30 cvs 1759: <h3><a name="sectc3210">Extension rules</a></h3>
1.18 cvs 1760:
1.30 cvs 1761: <p>The <tt>EXTENS</tt> section, which can only appear in an extension schema,
1.1 cvs 1762: defines complements to the rules in the primary schema (i.e. the structure
1763: schema to which the extension schema will be applied). More precisely, this
1764: section permits the addition to an existing type of local attributes,
1.18 cvs 1765: extensions, restrictions and fixed-value attributes.</p>
1.30 cvs 1766:
1767: <p>These additions can be applied to the root rule of the primary schema,
1.18 cvs 1768: designated by the keyword <tt>Root</tt>, or to any other explicitly named
1769: rule.</p>
1.30 cvs 1770:
1771: <p>Extension rules are separated from each other by a semicolon and each
1.18 cvs 1772: extension rule has the same syntax as a <a href="#sectc327">structure
1773: rule</a>, but the part which defines the constructor is absent.</p>
1.30 cvs 1774: <pre> ExtenRuleSeq = ExtensRule ';' < ExtensRule ';' > .
1.6 cvs 1775: ExtensRule = RootOrElem [ LocAttrSeq ]
1776: [ '+' '(' ExtensionSeq ')' ]
1777: [ '-' '(' RestrictSeq ')' ]
1778: [ 'WITH' FixedAttrSeq ] .
1.18 cvs 1779: RootOrElem = 'Root' / ElemID .</pre>
1780: </div>
1.1 cvs 1781:
1.18 cvs 1782: <div class="subsection">
1.30 cvs 1783: <h3><a name="sectc3211">Associated elements</a></h3>
1.1 cvs 1784:
1.30 cvs 1785: <p>If associated elements are necessary, they must be declared in a specific
1.18 cvs 1786: section of the structure schema, introduced by the keyword <tt>ASSOC</tt>.
1.1 cvs 1787: Each associated element type is specified like any other structured element.
1788: However, these types must not appear in any other element types of the schema,
1.18 cvs 1789: except in <tt>REFERENCE</tt> rules.</p>
1790: </div>
1.1 cvs 1791:
1.18 cvs 1792: <div class="subsection">
1.30 cvs 1793: <h3><a name="sectc3212">Units</a></h3>
1794:
1795: <p>The <tt>UNITS</tt> section of the structure schema contains the
1796: declarations of the element types which can be used in the external objects
1797: making up parts of the document or in objects of the class defined by the
1798: schema. As with associated elements, these element types are defined just
1799: like other structured element types. They can be used in the other element
1800: types of the schema, but they can also be used in any other rule of the
1801: schema.</p>
1802:
1803: <blockquote class="example">
1804: <p><strong>Example:</strong></p>
1.1 cvs 1805:
1.30 cvs 1806: <p>If references to notes are declared as units:</p>
1807: <pre>UNITS
1.18 cvs 1808: Ref_note = REFERENCE (Note);</pre>
1.30 cvs 1809:
1810: <p>then it is possible to use references to notes in a cell of a table, even
1811: when <tt>Table</tt> is an external structure schema. The <tt>Table</tt>
1812: schema must declare a cell to be a sequence of units, which can then be base
1813: element types (text, for example) or references to notes in the
1814: document.</p>
1815: <pre>Cell = LIST OF (UNITS);</pre>
1.18 cvs 1816: </blockquote>
1817: </div>
1.1 cvs 1818:
1.18 cvs 1819: <div class="subsection">
1.30 cvs 1820: <h3><a name="sectc3213">Skeleton elements</a></h3>
1.1 cvs 1821:
1.30 cvs 1822: <p>When editing a document which contains or must contain external references
1823: to several other documents, it may be necessary to load a large number of
1.1 cvs 1824: documents, simply to see the parts designated by the external references of
1825: the document while editing, or to access the source of included elements. In
1826: this case, the external documents are not modified and it is only necessary to
1827: see the elements of these documents which could be referenced. Because of
1828: this, the editor will suggest that the documents be loaded in ``skeleton''
1829: form. This form contains only the elements of the document explicitly
1.18 cvs 1830: mentioned in the <tt>EXPORT</tt> section of their structure schema and, for
1.1 cvs 1831: these elements, only the part of the contents specified in that section. This
1832: form has the advantage of being very compact, thus requiring very few
1833: resources from the editor. This is also the skeleton form which constitutes
1.18 cvs 1834: the expanded form of <a href="#inclusion">inclusions</a> with partial
1835: expansion.</p>
1.30 cvs 1836:
1837: <p>Skeleton elements must be declared explicitly in the <tt>EXPORT</tt>
1838: section of the structure schema that defines them. This section begins with
1839: the keyword <tt>EXPORT</tt> followed by a comma-separated list of the element
1.1 cvs 1840: types which must appear in the skeleton form and ending with a semicolon.
1.18 cvs 1841: These types must have been previously declared in the schema.</p>
1.30 cvs 1842:
1843: <p>For each skeleton element type, the part of the contents which is loaded by
1.1 cvs 1844: the editor, and therefore displayable, can be specified by putting the keyword
1.18 cvs 1845: <tt>WITH</tt> and the name of the contained element type to be loaded after
1.1 cvs 1846: the name of the skeleton element type. In this case only that named element,
1847: among all the elements contained in the exportable element type, will be
1.18 cvs 1848: loaded. If the <tt>WITH</tt> is absent, the entire contents of the skeleton
1.1 cvs 1849: element will be loaded by the editor. If instead, it is better that the
1850: skeleton form not load the contents of a particular element type, the keyword
1.18 cvs 1851: <tt>WITH</tt> must be followed by the word <tt>Nothing</tt>.</p>
1852: <pre> [ 'EXPORT' SkeletonSeq ]
1.1 cvs 1853:
1.30 cvs 1854: SkeletonSeq = SkelElem < ',' SkelElem > ';' .
1.1 cvs 1855: SkelElem = ElemID [ 'WITH' Contents ] .
1.18 cvs 1856: Contents = 'Nothing' / ElemID [ ExtStruct ] .</pre>
1.30 cvs 1857:
1.18 cvs 1858: <blockquote class="example">
1.30 cvs 1859: <p><strong>Example:</strong></p>
1860:
1861: <p>Suppose that, in documents of the article class, the element types
1862: Article_title, Figure, Section, Paragraph, and Biblio should appear in the
1863: skeleton form in order to make it easier to create external references to
1864: them from other documents. When loading an article in its skeleton form,
1865: all of these element types will be loaded except for paragraphs, but only
1866: the article title will be loaded in its entirety. For figures, the caption
1867: will be loaded, while for sections, the title will be loaded, and for
1.31 cvs 1868: bibliographic entries, only the title that they contain will be loaded. Note
1869: that bibliographic elements are defined in another structure schema, RefBib.
1.32 cvs 1870: To produce this result, the following declarations should be placed in the
1.31 cvs 1871: Article structure schema:</p>
1.30 cvs 1872: <pre>EXPORT
1.1 cvs 1873: Article_title,
1.5 cvs 1874: Figure With Caption,
1.1 cvs 1875: Section With Section_title,
1876: Paragraph With Nothing,
1.18 cvs 1877: Biblio With Biblio_title(RefBib);</pre>
1878: </blockquote>
1879: </div>
1.1 cvs 1880:
1.18 cvs 1881: <div class="subsection">
1.30 cvs 1882: <h3><a name="sectc3214">Exceptions</a></h3>
1.1 cvs 1883:
1.30 cvs 1884: <p>The behavior of the Thot editor and the actions that it performs are
1.1 cvs 1885: determined by the structure schemas. These actions are applied to all
1886: document and object types in accordance with their generic structure. For
1887: certain object types, such as tables and graphics, these actions are not
1888: sufficient or are poorly adapted and some special actions must be added to or
1889: substituted for certain standard actions. These special actions are called
1.18 cvs 1890: <em>exceptions</em>.</p>
1.30 cvs 1891:
1892: <p>Exceptions only inhibit or modify certain standard actions, but they can be
1.18 cvs 1893: used freely in every structure schema.</p>
1.30 cvs 1894:
1895: <p>Each structure schema can contain a section defining exceptions. It begins
1.18 cvs 1896: with the keyword <tt>EXCEPT</tt> and is composed of a sequence of exception
1.1 cvs 1897: declarations, separated by semicolons. Each declaration of an exception
1898: begins with the name of an element type or attribute followed by a colon. This
1899: indicates the element type or attribute to which the following exceptions
1.18 cvs 1900: apply. When the given element type name is a <a href="#sectd3285">mark
1901: pair</a>, and only in this case, the type name can be preceded by the keyword
1902: <tt>First</tt> or <tt>Second</tt>, to indicate if the exceptions which follow
1.1 cvs 1903: are associated with the first mark of the pair or the second. In the absence
1.18 cvs 1904: of this keyword, the first mark is used.</p>
1.30 cvs 1905:
1906: <p>When placed in an <a href="#sectc322">extension schema</a>, the keyword
1.18 cvs 1907: <tt>EXTERN</tt> indicates that the type name which follows is found in the
1.1 cvs 1908: principal schema (the schema being extended by the extension schema). The
1.18 cvs 1909: exceptions are indicated by a name. They are separated by semicolons.</p>
1910: <pre> [ 'EXCEPT' ExceptSeq ]
1.1 cvs 1911:
1.30 cvs 1912: ExceptSeq = Except ';' < Except ';' > .
1.1 cvs 1913: Except = [ 'EXTERN' ] [ FirstSec ] ExcTypeOrAttr
1914: ':' ExcValSeq .
1915: ExcTypeOrAttr = ElemID / AttrID .
1.30 cvs 1916: ExcValSeq = ExcValue < ',' ExcValue > .
1.19 cvs 1917: ExcValue ='NoCut' / 'NoCreate' / 'NoHMove' /
1918: 'NoVMove' / 'NoHResize' / 'NoVResize' /
1919: 'NoMove' / 'NoResize' / 'MoveResize' /
1920: 'NewWidth' / 'NewHeight' / 'NewHPos' /
1921: 'NewVPos' / 'Invisible' /
1.28 cvs 1922: 'NoSelect' / 'NoSpellCheck' /
1.1 cvs 1923: 'Hidden' / 'ActiveRef' /
1924: 'ImportLine' / 'ImportParagraph' /
1925: 'NoPaginate' / 'ParagraphBreak' /
1.19 cvs 1926: 'PageBreak' / 'PageBreakAllowed' / 'PageBreakPlace' /
1927: 'PageBreakRepetition' / 'PageBreakRepBefore' /
1.9 cvs 1928: 'HighlightChildren' / 'ExtendedSelection' /
1.36 ! cvs 1929: 'SelectParent' / 'ClickableSurface' /
1.29 cvs 1930: 'ReturnCreateNL' / 'ReturnCreateWithin' /
1931: 'IsDraw' / 'IsTable' /
1.19 cvs 1932: 'IsRow' / 'IsColHead' / 'IsCell' /
1933: 'NewPercentWidth' / 'ColRef' / 'ColSpan' /
1934: 'RowSpan' / 'SaveDocument' / 'Shadow' .</pre>
1.30 cvs 1935:
1936: <p>The following are the available exceptions:</p>
1.18 cvs 1937: <dl>
1.30 cvs 1938: <dt><tt>NoCut</tt></dt>
1939: <dd>This exception can only be applied to element types. Elements of a
1940: type to which this exception is applied cannot be deleted by the
1941: editor.</dd>
1942: <dt><tt>NoCreate</tt></dt>
1943: <dd>This exception can only be applied to element types. Elements of a
1944: type to which this exception is applied cannot be created by ordinary
1945: commands for creating new elements. These elements are usually created
1946: by special actions associated with other exceptions.</dd>
1947: <dt><tt>NoHMove</tt></dt>
1948: <dd>This exception can only be applied to element types. Elements of a
1949: type to which this exception is applied cannot be moved horizontally
1950: with the mouse. Their children elements cannot be moved either.</dd>
1951: <dt><tt>NoVMove</tt></dt>
1952: <dd>This exception can only be applied to element types. Elements of a
1953: type to which this exception is applied cannot be moved vertically with
1954: the mouse. Their children elements cannot be moved either.</dd>
1955: <dt><tt>NoMove</tt></dt>
1956: <dd>This exception can only be applied to element types. Elements of a
1957: type to which this exception is applied cannot be moved in any direction
1958: with the mouse. Their children elements cannot be moved either.</dd>
1959: <dt><tt>NoHResize</tt></dt>
1960: <dd>This exception can only be applied to element types. Elements of a
1961: type to which this exception is applied cannot be resized horizontally
1962: with the mouse. Their children elements cannot be resized either.</dd>
1963: <dt><tt>NoVResize</tt></dt>
1964: <dd>This exception can only be applied to element types. Elements of a
1965: type to which this exception is applied cannot be resized vertically
1966: with the mouse. Their children elements cannot be resized either.</dd>
1967: <dt><tt>NoResize</tt></dt>
1968: <dd>This exception can only be applied to element types. Elements of a
1969: type to which this exception is applied cannot be resized in any
1970: direction with the mouse. Their children elements cannot be resized
1971: either.</dd>
1972: <dt><tt>MoveResize</tt></dt>
1973: <dd>This exception can only be applied to element types. Elements of a
1974: type to which this exception is applied can be moved and resized in any
1975: direction with the mouse, even if one of their ancestor element has an
1976: exception that prevents moving or resizing. Their children elements can
1977: also be resized or moved.</dd>
1978: <dt><tt>NewWidth</tt></dt>
1979: <dd>This exception can only be applied to numeric attributes. If the
1980: width of an element which has this attribute is modified with the mouse,
1981: the value of the new width will be assigned to the attribute.</dd>
1982: <dt><tt>NewHeight</tt></dt>
1983: <dd>This exception can only be applied to numeric attributes. If the
1984: height of an element which has this attribute is modified with the
1985: mouse, the value of the new height will be assigned to the
1986: attribute.</dd>
1987: <dt><tt>NewHPos</tt></dt>
1988: <dd>This exception can only be applied to numeric attributes. If the
1989: horizontal position of an element which has this attribute is modified
1990: with the mouse, the value of the new horizontal position will be
1991: assigned to the attribute.</dd>
1992: <dt><tt>NewVPos</tt></dt>
1993: <dd>This exception can only be applied to numeric attributes. If the
1994: vertical position of an element which has this attribute is modified
1995: with the mouse, the value of the new vertical position will be assigned
1996: to the attribute.</dd>
1997: <dt><tt>Invisible</tt></dt>
1998: <dd>This exception can only be applied to attributes, but can be applied
1999: to all attribute types. It indicates that the attribute must not be
2000: seen by the user and that its value must not be changed directly. This
2001: exception is usually used when another exception manipulates the value
2002: of an attribute.</dd>
2003: <dt><tt>NoSelect</tt></dt>
2004: <dd>This exception can only be applied to element types. Elements of a
2005: type to which this exception is applied cannot be selected directly
2006: with the mouse, but they can be selected by other methods provided by
2007: the editor.</dd>
2008: <dt>NoSpellCheck</dt>
2009: <dd>This exception can only be applied to element types. Elements of a
2010: type to which this exception is applied are not taken into account by
2011: the spell checker.</dd>
2012: <dt><tt>Hidden</tt></dt>
2013: <dd>This exception can only be applied to element types. It indicates
2014: that elements of this type, although present in the document's
2015: structure, must not be shown to the user of the editor. In particular,
2016: the creation menus must not propose this type and the selection message
2017: must not pick it.</dd>
2018: <dt><tt>ActiveRef</tt></dt>
2019: <dd>This exception can only be applied to attributes of the reference
2020: type. It indicates that when the user of the editor makes a double
2021: click on an element which possesses a reference attribute having this
2022: exception, the element designated by the reference attribute will be
2023: selected.</dd>
2024: <dt><tt>ImportLine</tt></dt>
2025: <dd>This exception can only be applied to element types. It indicates
2026: that elements of this type should receive the content of imported text
2027: files. An element is created for each line of the imported file. A
2028: structure schema cannot contain several exceptions <tt>ImportLine</tt>
2029: and, if it contains one, it should not contain any exception
2030: <tt>ImportParagraph</tt>.</dd>
2031: <dt><tt>ImportParagraph</tt></dt>
2032: <dd>This exception can only be applied to element types. It indicates
2033: that elements of this type should receive the content of imported text
1.31 cvs 2034: files. An element is created for each paragraph of the imported file. A
2035: paragraph is a sequence of lines without any empty line. A structure
1.30 cvs 2036: schema cannot contain several exceptions <tt>ImportParagraph</tt> and,
2037: if it contains one, it should not contain any exception
2038: <tt>ImportLine</tt>.</dd>
2039: <dt><tt>NoPaginate</tt></dt>
2040: <dd>This exception can only be applied to the root element, i.e. the name
2041: that appear after the keyword <tt>STRUCTURE</tt> at the beginning of the
2042: structure schema. It indicates that the editor should not allow the
2043: user to paginate documents of that type.</dd>
2044: <dt><tt>ParagraphBreak</tt></dt>
2045: <dd>This exception can only be applied to element types. When the caret
2046: is within an element of a type to which this exception is applied, it is
2047: that element that will be split when the user hits the Return key.</dd>
2048: <dt><tt>ReturnCreateNL</tt></dt>
2049: <dd>This exception can only be applied to element types. When the caret
2050: is within an element of a type to which this exception is applied, the
2051: Return key simply inserts a New line character (code \212) at the
2052: current position. The Return key does not create a new element; it does
2053: not split the current element either.</dd>
2054: <dt><tt>ReturnCreateWithin</tt></dt>
2055: <dd>This exception can only be applied to element types. When the caret
2056: is within an element of a type to which this exception is applied, the
2057: Return key will create a new element within that element, not a sibling
2058: after that element.</dd>
2059: <dt><tt>HighlightChildren</tt></dt>
2060: <dd>This exception can only be applied to element types. Elements of a
2061: type to which this exception is applied are not highlighted themselves
1.32 cvs 2062: when they are selected in the main view, but all their children are
2063: highlighted instead. If children have this exception too, the process is
2064: applied recursively. Only the main view defined in the presentation
2065: schema is concerned. Tee exception is ignored for other views.</dd>
1.30 cvs 2066: <dt><tt>ExtendedSelection</tt></dt>
2067: <dd>This exception can only be applied to element types. The selection
2068: extension command (middle button of the mouse) only add the clicked
2069: element (if it has that exception) to the current selection, without
2070: selecting other elements between the current selection and the clicked
2071: element.</dd>
1.36 ! cvs 2072: <dt><code>SelectParent</code></dt>
! 2073: <dd>This exception can only be applied to element types. When the user
! 2074: clicks on an element of that type, the parent of the element is selected
! 2075: instead of the element itself.</dd>
! 2076: <dt><code>ClickableSurface</code></dt>
! 2077: <dd>This exception can only be applied to element types. When the user
! 2078: clicks within a child of an element of that type, this child is selected
! 2079: even if it is a graphic leaf that is not filled.</dd>
! 2080: <dt><code>IsDraw</code>, <code>IsTable</code>, <code>IsColHead</code>,
! 2081: <code>IsRow</code>, <code>IsCell</code></dt>
1.30 cvs 2082: <dd>These exceptions can only be applied to element types. Elements of a
2083: type to which these exceptions are applied are identified as Draws,
2084: Tables, Colheads, Rows or Cells and specific processing are applied to
2085: them.</dd>
1.36 ! cvs 2086: <dt><code>ColRef</code></dt>
1.30 cvs 2087: <dd>This exception can only be applied to attributes of the reference
2088: type. It indicates that this attribute refers to the column head (see
2089: exception IsColHead) which the element belongs to.</dd>
1.36 ! cvs 2090: <dt><code>ColSpan</code>, <code>RowSpan</code></dt>
1.31 cvs 2091: <dd>These exceptions can only be applied to numeric attributes of cells.
1.30 cvs 2092: They indicate that attribute values give how many columns or rows the
2093: element spans.</dd>
1.36 ! cvs 2094: <dt><code>Shadow</code></dt>
1.30 cvs 2095: <dd>This exception can only be applied to element types. Text of elements
2096: of a type to which this exception is applied are displayed and printed
2097: as a set of stars ('*').</dd>
1.18 cvs 2098: </dl>
1.30 cvs 2099:
1.18 cvs 2100: <blockquote class="example">
1.30 cvs 2101: <p><strong>Example:</strong></p>
2102:
2103: <p>Consider a structure schema for object-style graphics which defines the
2104: Graphic_object element type with the associated Height and Weight numeric
2105: attributes. Suppose that we want documents of this class to have the
2106: following qualities:</p>
2107: <ul>
2108: <li>Whenever the width or height of an object is changed using the mouse,
2109: the new values are stored in the object's Width and Height
2110: attributes.</li>
2111: <li>The user should not be able to change the values of the Width and
2112: Height attributes via the Attributes menu of the Thot editor.</li>
2113: </ul>
2114:
2115: <p>The following exceptions will produce this effect.</p>
2116: <pre>STRUCT
1.1 cvs 2117: ...
1.5 cvs 2118: Graphics_object (ATTR Height = Integer; Width = Integer)
1.1 cvs 2119: = GRAPHICS with Height ?= 10, Width ?= 10;
2120: ...
2121: EXCEPT
2122: Height: NewHeight, Invisible;
1.18 cvs 2123: Width: NewWidth, Invisible;</pre>
2124: </blockquote>
2125: </div>
2126: </div>
1.1 cvs 2127:
1.18 cvs 2128: <div class="section">
1.30 cvs 2129: <h2><a name="sectb33">Some examples</a></h2>
1.1 cvs 2130:
1.30 cvs 2131: <p>In order to illustrate the principles of the document model and the syntax
2132: of the S language, this section presents two examples of structure schemas.
2133: One defines a class of documents, the other defines a class of objects.</p>
1.1 cvs 2134:
1.18 cvs 2135: <div class="subsection">
1.30 cvs 2136: <h3><a name="sectc331">A class of documents: articles</a></h3>
1.1 cvs 2137:
1.30 cvs 2138: <p>This example shows a possible structure for articles published in a
2139: journal. Text between braces is comments.</p>
1.18 cvs 2140: <pre>STRUCTURE Article; { This schema defines the Article class }
1.1 cvs 2141: DEFPRES ArticleP; { The default presentation schema is
2142: ArticleP }
2143: ATTR { Global attribute definitions }
2144: WordType = Definition, IndexWord, DocumentTitle;
2145: { A single global attribute is defined, with three values }
2146: STRUCT { Definition of the generic structure }
2147: Article = BEGIN { The Article class has an aggregate
2148: structure }
2149: Title = BEGIN { The title is an aggregate }
2150: French_title =
2151: Text WITH Language='Fran\347ais';
2152: English_title =
2153: Text WITH Language='English';
2154: END;
2155: Authors =
2156: LIST OF (Author
2157: (ATTR Author_type=principal,secondary)
2158: { The Author type has a local attribute }
2159: = BEGIN
2160: Author_name = Text;
2161: Info = Paragraphs ;
2162: { Paragraphs is defined later }
2163: Address = Text;
2164: END
2165: );
2166: Keywords = Text;
2167: { The journal's editor introduces the article
2168: with a short introduction, in French and
2169: in English }
2170: Introduction =
2171: BEGIN
2172: French_intr = Paragraphs WITH
2173: Language='Fran\347ais';
2174: English_intr = Paragraphs WITH
2175: Language='English';
2176: END;
2177: Body = Sections; { Sections are defined later }
2178: { Appendixes are only created on demand }
2179: ? Appendices =
2180: LIST OF (Appendix =
2181: BEGIN
2182: Appendix_Title = Text;
2183: Appendix_Contents = Paragraphs;
2184: END
2185: );
2186: END; { End of the Article aggregate }
2187:
2188: Sections = LIST [2..*] OF (
2189: Section = { At least 2 sections }
2190: BEGIN
2191: Section_title = Text;
2192: Section_contents =
2193: BEGIN
2194: Paragraphs;
2195: Sections; { Sections at a lower level }
2196: END;
2197: END
2198: );
2199:
2200: Paragraphs = LIST OF (Paragraph = CASE OF
2201: Enumeration =
2202: LIST [2..*] OF
2203: (Item = Paragraphs);
2204: Isolated_formula = Formula;
2205: LIST OF (UNIT);
2206: END
2207: );
2208:
2209: ASSOC { Associated elements definitions }
2210:
2211: Figure = BEGIN
1.5 cvs 2212: Figure_caption = Text;
1.1 cvs 2213: Illustration = NATURE;
2214: END;
2215:
2216: Biblio_citation = CASE OF
2217: Ref_Article =
2218: BEGIN
2219: Authors_Bib = Text;
2220: Article_Title = Text;
2221: Journal = Text;
2222: Page_Numbers = Text;
2223: Date = Text;
2224: END;
2225: Ref_Livre =
2226: BEGIN
2227: Authors_Bib; { Defined above }
2228: Book_Title = Text;
2229: Editor = Text;
2230: Date; { Defined above }
2231: END;
2232: END;
2233:
2234: Note = Paragraphs - (Ref_note);
2235:
2236: UNITS { Elements which can be used in objects }
2237:
2238: Ref_note = REFERENCE (Note);
2239: Ref_biblio = REFERENCE (Biblio_citation);
2240: Ref_figure = REFERENCE (Figure);
2241: Ref_formula = REFERENCE (Isolated_formula);
2242:
2243: EXPORT { Skeleton elements }
2244:
2245: Title,
1.5 cvs 2246: Figure with Figure_caption,
1.1 cvs 2247: Section With Section_title;
2248:
1.18 cvs 2249: END { End of the structure schema }</pre>
1.30 cvs 2250:
2251: <p>This schema is very complete since it defines both paragraphs and
1.1 cvs 2252: bibliographic citations. These element types could just as well be defined in
1.18 cvs 2253: other structure schemas, as is the case with the <tt>Formula</tt> class. All
1.1 cvs 2254: sorts of other elements can be inserted into an article, since a paragraph can
2255: contain any type of unit. Similarly, figures can be any class of document or
1.18 cvs 2256: object that the user chooses.</p>
1.30 cvs 2257:
2258: <p>Generally, an article doesn't contain appendices, but it is possible to add
1.1 cvs 2259: them on explicit request: this is the effect of the question mark before the
1.18 cvs 2260: word Appendices.</p>
1.30 cvs 2261:
2262: <p>The Figure, Biblio_citation and Note elements are associated elements.
2263: Thus, they are only used in <tt>REFERENCE</tt> statements.</p>
2264:
2265: <p>Various types of cross-references can be put in paragraphs. They can also
2266: be placed the objects which are part of the article, since the
2267: cross-references are defined as units (<tt>UNITS</tt>).</p>
2268:
2269: <p>There is a single restriction to prevent the creation of Ref_note elements
1.18 cvs 2270: within notes.</p>
1.30 cvs 2271:
2272: <p>It is worth noting that the S language permits the definition of recursive
1.1 cvs 2273: structures like sections: a section can contain other sections (which are thus
2274: at the next lower level of the document tree). Paragraphs are also recursive
2275: elements, since a paragraph can contain an enumeration in which each element
1.18 cvs 2276: (<tt>Item</tt>) is composed of paragraphs.</p>
2277: </div>
1.1 cvs 2278:
1.18 cvs 2279: <div class="subsection">
1.30 cvs 2280: <h3><a name="sectc332">A class of objects: mathematical formulas</a></h3>
1.1 cvs 2281:
1.30 cvs 2282: <p>The example below defines the <tt>Formula</tt> class which is used in
2283: Article documents. This class represents mathematical formulas with a rather
2284: simple structure, but sufficient to produce a correct rendition on the screen
2285: or printer. To support more elaborate operations (formal or numeric
1.1 cvs 2286: calculations), a finer structure should be defined. This class doesn't use any
1.18 cvs 2287: other class and doesn't define any associated elements or units.</p>
2288: <pre>STRUCTURE Formula;
1.1 cvs 2289: DEFPRES FormulaP;
2290:
2291: ATTR
2292: String_type = Function_name, Variable_name;
2293:
2294: STRUCT
2295: Formula = Expression;
2296: Expression = LIST OF (Construction);
2297: Construction = CASE OF
2298: TEXT; { Simple character string }
2299: Index = Expression;
2300: Exponent = Expression;
2301: Fraction =
2302: BEGIN
1.6 cvs 2303: Numerator = Expression;
1.1 cvs 2304: Denominator = Expression;
2305: END;
2306: Root =
2307: BEGIN
2308: ? Order = TEXT;
2309: Root_Contents = Expression;
2310: END;
2311: Integral =
2312: BEGIN
2313: Integration_Symbol = SYMBOL;
2314: Lower_Bound = Expression;
2315: Upper_Bound = Expression;
2316: END;
2317: Triple =
2318: BEGIN
2319: Princ_Expression = Expression;
2320: Lower_Expression = Expression;
2321: Upper_Expression = Expression;
2322: END;
2323: Column = LIST [2..*] OF
2324: (Element = Expression);
2325: Parentheses_Block =
2326: BEGIN
2327: Opening = SYMBOL;
2328: Contents = Expression;
2329: Closing = SYMBOL;
2330: END;
2331: END; { End of Choice Constructor }
1.18 cvs 2332: END { End of Structure Schema }</pre>
1.30 cvs 2333:
2334: <p>This schema defines a single global attribute which allows functions and
1.1 cvs 2335: variables to be distinguished. In the presentation schema, this attribute can
2336: be used to choose between roman (for functions) and italic characters (for
1.18 cvs 2337: variables).</p>
1.30 cvs 2338:
2339: <p>A formula's structure is that of a mathematical expression, which is itself
2340: a sequence of mathematical constructions. A mathematical construction can be
1.1 cvs 2341: either a simple character string, an index, an exponent, a fraction, a root,
2342: etc. Each of these mathematical constructions has a sensible structure which
2343: generally includes one or more expressions, thus making the formula class's
1.18 cvs 2344: structure definition recursive.</p>
1.30 cvs 2345:
2346: <p>In most cases, the roots which appear in the formulas are square roots and
1.1 cvs 2347: their order (2) is not specified. This is why the Order component is marked
2348: optional by a question mark. When explicitly requested, it is possible to add
1.18 cvs 2349: an order to a root, for example for cube roots (order = 3).</p>
1.30 cvs 2350:
2351: <p>An integral is formed by an integration symbol, chosen by the user (simple
1.1 cvs 2352: integral, double, curvilinear, etc.), and two bounds. A more fine-grained
2353: schema would add components for the integrand and the integration variable.
2354: Similarly, the Block_Parentheses construction leaves the choice of opening and
2355: closing symbols to the user. They can be brackets, braces, parentheses,
1.18 cvs 2356: etc.</p>
2357: </div>
2358: </div>
2359: <hr>
2360: </div>
1.1 cvs 2361:
1.18 cvs 2362: <div class="chapter">
2363: <h1><a name="sect4">The P Language</a></h1>
1.1 cvs 2364:
1.18 cvs 2365: <div class="section">
1.30 cvs 2366: <h2><a name="sectb41">Document presentation</a></h2>
1.1 cvs 2367:
1.30 cvs 2368: <p>Because of the model adopted for Thot, the presentation of documents is
1.1 cvs 2369: clearly separated from their structure and content. After having presented
2370: the logical structure of documents, we now detail the principles implemented
1.18 cvs 2371: for their presentation. The concept of <em>presentation</em> encompasses what
1.5 cvs 2372: is often called the page layout, the composition, or the document style. It
1.18 cvs 2373: is the set of operations which display the document on the screen or print it
2374: on paper. Like logical structure, document presentation is defined
2375: generically with the help of a language, called P.</p>
1.1 cvs 2376:
1.18 cvs 2377: <div class="subsection">
1.30 cvs 2378: <h3><a name="sectc411">Two levels of presentation</a></h3>
1.1 cvs 2379:
1.30 cvs 2380: <p>The link between structure and presentation is clear: the logical
2381: organization of a document is used to carry out its presentation, since the
2382: purpose of the presentation is to make evident the organization of the
2383: document. But the presentation is equally dependent on the device used to
2384: render the document. Certain presentation effects, notably changes of font or
2385: character set, cannot be performed on all printers or on all screens. This is
2386: why Thot uses a two-level approach, where the presentation is first described
2387: in abstract terms, without taking into account each particular device, and
2388: then the presentation is realized within the constraints of a given
2389: device.</p>
2390:
2391: <p>Thus, presentation is only described as a function of the structure of the
1.1 cvs 2392: documents and the image that would be produced on an idealized device. For
2393: this reason, presentation descriptions do not refer to any device
1.18 cvs 2394: characteristics: they describe <em>abstract presentations</em> which can be
2395: concretized on different devices.</p>
1.30 cvs 2396:
2397: <p>A presentation description also defines a <em>generic presentation</em>,
2398: since it describes the appearance of a class of documents or objects. This
2399: generic presentation must also be applied to document and object instances,
2400: each conforming to its generic logical structure, but with all the allowances
2401: that were called to mind above: missing elements, constructed elements with
2402: other logical structures, etc.</p>
2403:
2404: <p>In order to preserve the homogeneity between documents and objects,
1.1 cvs 2405: presentation is described with a single set of tools which support the layout
2406: of a large document as well as the composition of objects like a graphical
2407: figure or mathematical formula. This unity of presentation description tools
2408: contrasts with the traditional approach, which focuses more on documents than
2409: objects and thus is based on the usual typographic conventions, such as the
2410: placement of margins, indentations, vertical spaces, line lengths,
1.18 cvs 2411: justification, font changes, etc.</p>
2412: </div>
1.1 cvs 2413:
1.18 cvs 2414: <div class="subsection">
1.30 cvs 2415: <h3><a name="sectc412">Boxes</a></h3>
1.1 cvs 2416:
1.30 cvs 2417: <p>To assure the homogeneity of tools, all presentation in Thot, for documents
2418: as well as for the objects which they contain, is based on the notion of the
1.18 cvs 2419: <em>box</em>, such as was implemented in T<sub><big>E</big></sub>X.</p>
1.30 cvs 2420:
2421: <p>Corresponding to each element of the document is a box, which is the
1.1 cvs 2422: rectangle enclosing the element on the display device (screen or sheet of
1.18 cvs 2423: paper); the outline of this rectangle is not visible, except when a <a
2424: href="#sectc4230a"><tt>ShowBox</tt> rule</a> applies to the element. The sides
2425: of the box are parallel to the sides of the screen or the sheet of paper. By
2426: way of example, a box is associated with a character string, a line of text, a
2427: page, a paragraph, a title, a mathematical formula, or a table cell.</p>
1.30 cvs 2428:
2429: <p>Whatever element it corresponds to, each box possesses four sides and four
1.18 cvs 2430: axes, which we designate as follows (<a href="#boxes">see figure</a>):</p>
2431: <dl>
1.30 cvs 2432: <dt><tt>Top</tt></dt>
2433: <dd>the upper side,</dd>
2434: <dt><tt>Bottom</tt></dt>
2435: <dd>the lower side,</dd>
2436: <dt><tt>Left</tt></dt>
2437: <dd>the left side,</dd>
2438: <dt><tt>Right</tt></dt>
2439: <dd>the right side,</dd>
2440: <dt><tt>VMiddle</tt></dt>
2441: <dd>the vertical axis passing through the center of the box,</dd>
2442: <dt><tt>HMiddle</tt></dt>
2443: <dd>the horizontal axis passing through the center of the box,</dd>
2444: <dt><tt>VRef</tt></dt>
2445: <dd>the vertical reference axis,</dd>
2446: <dt><tt>HRef</tt></dt>
2447: <dd>the horizontal reference axis.</dd>
1.18 cvs 2448: </dl>
2449:
2450: <div class="figure">
2451: <hr>
2452: <pre> Left VRef VMiddle Right
1.1 cvs 2453: : :
2454: Top -----------------------------
2455: | : : |
2456: | : : |
2457: | : : |
2458: | : : |
2459: | : : |
2460: HMiddle ..|...........................|..
2461: | : : |
2462: | : : |
2463: HRef ..|...........................|..
2464: | : : |
2465: | : : |
2466: Bottom -----------------------------
1.18 cvs 2467: : :</pre>
1.30 cvs 2468:
2469: <p align="center"><em><a name="boxes">The sides and axes of
2470: boxes</a><em></em></em></p>
1.18 cvs 2471: <hr>
1.30 cvs 2472: </div>
1.19 cvs 2473:
1.30 cvs 2474: <p>The principal role of boxes is to set the extent and position of the images
2475: of the different elements of a document with respect to each other on the
1.1 cvs 2476: reproduction device. This is done by defining relations between the boxes of
2477: different elements which give relative extents and positions to these
1.18 cvs 2478: boxes.</p>
1.30 cvs 2479:
2480: <p>There are three types of boxes:</p>
1.18 cvs 2481: <ul>
1.30 cvs 2482: <li>boxes corresponding to structural elements of the document,</li>
2483: <li>presentation boxes,</li>
2484: <li>page layout boxes.</li>
1.18 cvs 2485: </ul>
1.30 cvs 2486:
2487: <p><strong>Boxes corresponding to structural elements of the document</strong>
1.1 cvs 2488: are those which linked to each of the elements (base or structured) of the
2489: logical structure of the document. Such a box contains all the contents of
1.18 cvs 2490: the element to which it corresponds (there is an exception: see <a
2491: href="#sectc4220">rules <tt>VertOverflow</tt> and <tt>HorizOverflow</tt></a>).
2492: These boxes form a tree-like structure, identical to that of the structural
2493: elements to which they correspond. This tree expresses the inclusion
2494: relationships between the boxes: a box includes all the boxes of its subtree.
2495: On the other hand, there are no predefined rules for the relative positions of
2496: the included boxes. If they are at the same level, they can overlap, be
2497: contiguous, or be disjoint. The rules expressed in the generic presentation
2498: specify their relative positions.</p>
1.30 cvs 2499:
2500: <p><strong>Presentation boxes</strong> represent elements which are not found
2501: in the logical structure of the document but which are added to meet the needs
2502: of presentation. These boxes are linked to the elements of the logical
2503: structure that are best suited to bringing them out. For example, they are
2504: used to add the character string ``Summary:'' before the summary in the
2505: presentation of a report or to represent the fraction bar in a formula, or
2506: also to make the title of a field in a form appear. These elements have no
2507: role in the logical structure of the document: the presence of a Summary
2508: element in the document does not require the creation of another structural
2509: object to hold the word ``Summary''. Similarly, if a Fraction element contains
2510: both a Numerator element and a Denominator element, the fraction bar has no
2511: purpose structurally. On the other hand, these elements of the presentation
2512: are important for the reader of the reproduced document or for the user of an
1.1 cvs 2513: editor. This is why they must appear in the document's image. It is the
2514: generic presentation which specifies the presentation boxes to add by
2515: indicating their content (a base element for which the value is specified) and
2516: the position that they must take in the tree of boxes. During editing, these
1.18 cvs 2517: boxes cannot be modified by the user.</p>
1.30 cvs 2518:
2519: <p><strong>Page layout boxes</strong> are boxes created implicitly by the page
1.1 cvs 2520: layout rules. These rules indicate how the contents of a structured element
2521: must be broken into lines and pages. In contrast to presentation boxes, these
2522: line and page boxes do not depend on the logical structure of the document,
1.18 cvs 2523: but rather on the physical constraints of the output devices: character size,
2524: height and width of the window on the screen or of the sheet of paper.</p>
2525: </div>
1.1 cvs 2526:
1.18 cvs 2527: <div class="subsection">
1.30 cvs 2528: <h3><a name="sectc413">Views and visibility</a></h3>
1.1 cvs 2529:
1.30 cvs 2530: <p>One of the operations that one might wish to perform on a document is to
2531: view it is different ways. For this reason, it is possible to define several
1.18 cvs 2532: <em>views</em> for the same document, or better yet, for all documents of the
1.1 cvs 2533: same class. A view is not a different presentation of the document, but
2534: rather a filter which only allows the display of certain parts of the
2535: document. For example, it might be desirable to see only the titles of
2536: chapters and sections in order to be able to move rapidly through the
2537: document. Such a view could be called a ``table of contents''. It might also
2538: be desirable to see only the mathematical formulas of a document in order to
2539: avoid being distracted by the non-mathematical aspects of the document. A
1.18 cvs 2540: ``mathematics'' view could provide this service.</p>
1.30 cvs 2541:
2542: <p>Views, like presentation, are based on the generic logical structure. Each
1.1 cvs 2543: document class, and each generic presentation, can be provided with views
2544: which are particularly useful for that class or presentation. For each view,
1.18 cvs 2545: the <em>visibility</em> of elements is defined, indicated whether or not the
1.1 cvs 2546: elements must be presented to the user. The visibility is calculated as a
2547: function of the type of the elements or their hierarchical position in the
2548: structure of the document. Thus, for a table of contents, all the ``Chapter
2549: Title'' and ``Section Title'' elements are made visible. However, the
2550: hierarchical level could be used to make the section titles invisible below a
2551: certain threshold level. By varying this threshold, the granularity of the
2552: view can be varied. In the ``mathematics'' view, only Formula elements would
1.18 cvs 2553: be made visible, no matter what their hierarchical level.</p>
1.30 cvs 2554:
2555: <p>Because views are especially useful for producing a synthetic image of the
1.1 cvs 2556: document, it is necessary to adapt the presentation of the elements to the
2557: view in which they appear. For example, it is inappropriate to have a page
2558: break before every chapter title in the table of contents. Thus, generic
2559: presentations take into account the possible views and permit each element
1.18 cvs 2560: type's presentation to vary according the view in which its image appears.</p>
1.30 cvs 2561:
2562: <p><a name="views">Views</a> are also used, when editing documents, to display
1.1 cvs 2563: the associated elements. So, in addition to the primary view of the document,
2564: there can be a ``notes'' view and a ``figures'' view which contain,
2565: respectively, the associated elements of the Note and Figure types. In this
2566: way, it is possible to see simultaneously the text which refers to these
2567: elements and the elements themselves, even if they will be separated when
1.18 cvs 2568: printed.</p>
2569: </div>
1.1 cvs 2570:
1.18 cvs 2571: <div class="subsection">
1.30 cvs 2572: <h3><a name="sectc414">Pages</a></h3>
1.1 cvs 2573:
1.30 cvs 2574: <p>Presentation schemas can be defined which display the document as a long
1.1 cvs 2575: scroll, without page breaks. This type of schema is particularly well-suited
2576: to the initial phase of work on a document, where jumps from page to page
2577: would hinder composing and reading the document on a screen. In this case,
2578: the associated elements (such as notes), which are normally displayed in the
2579: page footer, are presented in a separate window. But, once the document is
2580: written, it may be desirable to display the document on the screen in the same
2581: manner in which it will be printed. So, the presentation schema must define
1.18 cvs 2582: pages.</p>
1.30 cvs 2583:
2584: <p>The P language permits the specification of the dimensions of pages as well
2585: as their composition. It is possible to generate running titles, page
2586: numbers, zones at the bottom of the page for notes, etc. The editor follows
2587: this model and inserts page break marks in the document which are used during
2588: printing, insuring that the pages on paper are the same as on the screen.</p>
2589:
2590: <p>Once a document has been edited with a presentation schema defining pages,
2591: it contains page marks. But it is always possible to edit the document using
2592: a schema without pages. In this case, the page marks are simply ignored by
2593: the editor. They are considered again as soon as a schema with pages is used.
1.18 cvs 2594: Thus, the user is free to choose between schemas with and without pages.</p>
1.30 cvs 2595:
2596: <p>Thot treats the page break, rather than the page itself, as a box. This
2597: page break box contains all the elements of one page's footer, a rule marking
2598: the edge of this page, and all the elements of the next page's header. The
1.1 cvs 2599: elements of the header and footer can be running titles, page number,
2600: associated elements (notes, for example), etc. All these elements, as well as
2601: their content and graphical appearance, are defined by the generic
1.18 cvs 2602: presentation.</p>
2603: </div>
1.1 cvs 2604:
1.18 cvs 2605: <div class="subsection">
1.30 cvs 2606: <h3><a name="sectc415">Numbering</a></h3>
1.1 cvs 2607:
1.30 cvs 2608: <p>Many elements are numbered in documents: pages, chapters, sections,
2609: formulas, theorems, notes, figures, bibliographic references, exercises,
2610: examples, lemmas, etc. Because Thot has a notion of logical structure, all of
2611: these numbers (with the exception of pages) are redundant with information
2612: implicit in the logical structure of the document. Such numbers are simply a
2613: way to make the structure of the document more visible. So, they are part of
2614: the document's presentation and are calculated by the editor from the logical
1.1 cvs 2615: structure. The structure does not contain numbers as such; it only defines
2616: relative structural positions between elements, which serve as ordering
1.18 cvs 2617: relations on these elements.</p>
1.30 cvs 2618:
2619: <p>If the structure schema defines the body of a document as a sequence of at
1.18 cvs 2620: least two chapters:</p>
2621: <pre>Body = LIST [2..*] OF Chapter;</pre>
1.30 cvs 2622:
2623: <p>the sequence defined by the list constructor is ordered and each chapter
2624: can be assigned a number based on its rank in the Body list. Therefore, all
1.18 cvs 2625: elements contained in lists a the structure of a document can be numbered, but
2626: they are not the only ones. The tree structure induced by the aggregate,
2627: list, and choice constructors (excluding references) defines a total order on
2628: the elements of the document's primary structure. So, it is possible to
2629: define a numbering which uses this order, filtering elements according to
2630: their type so that only certain element types are taken into account in the
2631: numbering. In this way, it possible to number all the theorems and lemmas of
2632: a chapter in the same sequence of numbers, even when they are not part of the
2633: same list constructor and appear at different levels of the document's tree.
2634: By changing the filter, they can be numbered separately: one sequence of
2635: numbers for theorems, another for the lemmas.</p>
1.30 cvs 2636:
2637: <p>Associated elements pose a special problem, since they are not part of the
1.1 cvs 2638: document's primary structure, but are attached only by references, which
2639: violate the total order of the document. Then, these associated elements are
2640: frequently numbered, precisely because the number is an effective way to
2641: visualize the reference. In order to resolve this problem, Thot implicitly
2642: defines a list constructor for each type of associated element, gathering
2643: together (and ordering) these elements. Thus, the associated elements can be
1.18 cvs 2644: numbered by type.</p>
1.30 cvs 2645:
2646: <p>Since they are calculated from the document's logical structure and only
2647: for the needs of the presentation, numbers are presentation elements,
2648: described by presentation boxes, just like the fraction bar or the word
2649: ``Summary''. Nevertheless, numbers differ from these other boxes because their
2650: content varies from instance to instance, even though they are of the same
2651: type, whereas all fraction bars are horizontal lines and the same word
2652: ``Summary'' appears at the head of every document's summary.</p>
1.18 cvs 2653: </div>
1.1 cvs 2654:
1.18 cvs 2655: <div class="subsection">
1.34 cvs 2656: <h3><a name="sectc416">Presentation properties</a></h3>
1.1 cvs 2657:
1.34 cvs 2658: <p>The principal properties which determine document presentation are the
1.18 cvs 2659: <em>positions</em> and <em>dimensions</em> of boxes, the <em>font</em>, the
2660: <em>style</em>, the <em>size</em>, the <em>underlining</em> and the
1.34 cvs 2661: <em>color</em> of their content. From these properties, and some others of
2662: less importance, it is possible to represent the usual typographic properties
2663: for the textual parts of the document. These same properties can be used to
1.1 cvs 2664: describe the geometry of the non-textual elements, even though they are
1.18 cvs 2665: two-dimensional elements unlike the text, which is linear.</p>
1.30 cvs 2666:
2667: <p>As we have already seen, the positions of the boxes always respect the
2668: rule of enclosure: a box in the tree encloses all the boxes of the next lower
1.34 cvs 2669: level which are attached to it. The positional properties permit the
1.30 cvs 2670: specification of the position of each box in relation to the enclosing box or
2671: to its sibling boxes (boxes directly attached to the same enclosing box in the
2672: tree of boxes).</p>
2673:
1.34 cvs 2674: <p>The presentation properties also provide control over the dimensions of the
1.1 cvs 2675: boxes. The dimensions of a box can depend either on its content or on its
2676: context (its sibling boxes and the enclosing box). Each dimension (height or
1.18 cvs 2677: width) can be defined independently of the other.</p>
1.30 cvs 2678:
1.34 cvs 2679: <p>Because of the position and dimension properties, it is possible to do the
1.1 cvs 2680: same things that are normally done in typography by changing margins, line
2681: lengths, and vertical or horizontal skips. This approach can also align or
1.18 cvs 2682: center elements and groups of elements.</p>
1.30 cvs 2683:
1.34 cvs 2684: <p>In contrast to the position and dimension properties, the font, style,
1.30 cvs 2685: size, underlining, and color do not concern the box itself (the rectangle
1.34 cvs 2686: delimiting the element), but its content. These properties indicate the
1.30 cvs 2687: typographic attributes which must be applied to the text contained in the box,
2688: and by extension, to all base elements.</p>
2689:
1.34 cvs 2690: <p>For text, the font property is used to change the family of characters
1.1 cvs 2691: (Times, Helvetica, Courier, etc.); the style is used to obtain italic or
2692: roman, bold or light characters; the size determines the point size of the
2693: characters; underlining defines the type and thickness of the lines drawn
1.18 cvs 2694: above, below, or through the characters.</p>
1.30 cvs 2695:
1.34 cvs 2696: <p>For graphics, the line style property can be either solid, dotted, or
2697: dashed; the line thickness property controls the width of the lines; the fill
2698: pattern property determines how closed geometric figures must be filled.</p>
1.30 cvs 2699:
1.34 cvs 2700: <p>While some of the properties which determine the appearance of a box's
1.1 cvs 2701: contents make sense only for one content type (text or graphic), other
1.34 cvs 2702: properties apply to all content types: these are the color properties. These
1.18 cvs 2703: indicate the color of lines and the background color.</p>
2704: </div>
2705: </div>
1.1 cvs 2706:
1.18 cvs 2707: <div class="section">
1.30 cvs 2708: <h2><a name="sectb42">Presentation description language</a></h2>
2709:
1.34 cvs 2710: <p>A generic presentation defines the values of presentation properties (or
1.30 cvs 2711: the way to calculate those values) for a generic structure, or more precisely,
2712: for all the element types and all the global and local attributes defined in
1.34 cvs 2713: that generic structure. This definition of the presentation properties is
1.30 cvs 2714: made with the P language. A program written in this language, that is a
2715: generic presentation expressed in P, is call a <em>presentation schema</em>.
2716: This section describes the syntax and semantics of the language, using the
2717: same <a href="#sectc321">meta-language</a> as was used for the definition of
2718: the S language.</p>
1.1 cvs 2719:
1.30 cvs 2720: <p>Recall that it is possible to write many different presentation schemas for
1.1 cvs 2721: the same class of documents or objects. This allows users to choose for a
2722: document the graphical appearance which best suits their type of work or
1.18 cvs 2723: their personal taste.</p>
1.1 cvs 2724:
1.18 cvs 2725: <div class="subsection">
1.30 cvs 2726: <h3><a name="sectc421">The organization of a presentation schema</a></h3>
1.1 cvs 2727:
1.30 cvs 2728: <p>A presentation schema begins with the word <tt>PRESENTATION</tt> and ends
2729: with the word <tt>END</tt>. The word <tt>PRESENTATION</tt> is followed by the
2730: name of the generic structure to which the presentation will be applied. This
2731: name must be the same as that which follows the keyword <tt>STRUCTURE</tt> in
2732: the structure schema associated with the presentation schema.</p>
2733:
2734: <p>After this declaration of the name of the structure, the following sections
1.18 cvs 2735: appear (in order):</p>
2736: <ul>
1.30 cvs 2737: <li>Declarations of
2738: <ul>
2739: <li>all views,</li>
2740: <li>printed views,</li>
2741: <li>counters,</li>
2742: <li>presentation constants,</li>
2743: <li>variables,</li>
2744: </ul>
2745: </li>
2746: <li>default presentation rules,</li>
2747: <li>presentation box and page layout box definitions,</li>
2748: <li>presentation rules for structured elements,</li>
2749: <li>presentation rules for attributes,</li>
2750: <li>rules for transmitting values to attributes of included documents.</li>
1.18 cvs 2751: </ul>
1.30 cvs 2752:
2753: <p>Each of these sections is introduced by a keyword which is followed by a
1.18 cvs 2754: sequence of declarations. Every section is optional.</p>
2755: <pre> SchemaPres ='PRESENTATION' ElemID ';'
1.1 cvs 2756: [ 'VIEWS' ViewSeq ]
2757: [ 'PRINT' PrintViewSeq ]
2758: [ 'COUNTERS' CounterSeq ]
2759: [ 'CONST' ConstSeq ]
2760: [ 'VAR' VarSeq ]
2761: [ 'DEFAULT' ViewRuleSeq ]
2762: [ 'BOXES' BoxSeq ]
2763: [ 'RULES' PresentSeq ]
2764: [ 'ATTRIBUTES' PresAttrSeq ]
2765: [ 'TRANSMIT' TransmitSeq ]
2766: 'END' .
1.18 cvs 2767: ElemID = NAME .</pre>
2768: </div>
1.1 cvs 2769:
1.18 cvs 2770: <div class="subsection">
1.30 cvs 2771: <h3><a name="sectc422">Views</a></h3>
1.1 cvs 2772:
1.30 cvs 2773: <p>Each of the possible views must be declared in the presentation schema. As
1.18 cvs 2774: has <a href="#views">already been described</a>, the presentation rules for an
1.1 cvs 2775: element type can vary according to the view in which the element appears. The
2776: name of the view is used to designate the view to which the presentation rules
1.18 cvs 2777: apply (see the <a href="#inkeyword"><tt>IN</tt> instruction</a>). The
1.1 cvs 2778: definition of the view's contents are dispersed throughout the presentation
2779: rules attached to the different element types and attributes. The
1.18 cvs 2780: <tt>VIEWS</tt> section is simply a sequence of view names separated by commas
2781: and terminated by a semi-colon.</p>
1.30 cvs 2782:
2783: <p>One of the view names (and only one) can be followed by the keyword
1.18 cvs 2784: <tt>EXPORT</tt>. This keyword identifies the view which presents the members
2785: of the document class in <a href="#sectc3213">skeleton form</a>. The
2786: graphical appearance and the content of this view is defined just as with
2787: other views, but it is useless to specify presentation rules concerning this
2788: view for the elements which are not loaded in the skeleton form.</p>
1.30 cvs 2789:
2790: <p>It is not necessary to declare any views; in this case there is a single
1.1 cvs 2791: unnamed view. If many views are declared, the first view listed is considered
2792: the principal view. The principal view is the one to which all rules that are
1.18 cvs 2793: not preceded by an indication of a view will apply (see the <a
2794: href="#inkeyword">instruction <tt>IN</tt></a>).</p>
1.30 cvs 2795:
2796: <p>The principal view is the the one which the editor presents on the screen
2797: when the user asks to create or edit a document. Thus, it makes sense to put
2798: the most frequently used view at the head of the list. But if the structure
1.18 cvs 2799: schema contains <a href="#sectc3213">skeleton elements</a> and is loaded in
2800: its skeleton form, the view whose name is followed by the keyword
2801: <tt>EXPORT</tt> will be opened and no other views can be opened.</p>
2802: <pre> 'VIEWS' ViewSeq
1.1 cvs 2803: ViewSeq = ViewDeclaration
1.30 cvs 2804: < ',' ViewDeclaration > ';' .
1.1 cvs 2805: ViewDeclaration = ViewID [ 'EXPORT' ] .
1.18 cvs 2806: ViewID = NAME .</pre>
1.30 cvs 2807:
1.18 cvs 2808: <blockquote class="example">
1.30 cvs 2809: <p><strong>Example:</strong></p>
2810:
2811: <p>When editing a report, it might be useful have views of the table of
2812: contents and of the mathematical formulas, in addition to the principal view
2813: which shows the document in its entirety. To achieve this, a presentation
2814: schema for the Report class would have the following <tt>VIEWS</tt>
2815: section:</p>
2816: <pre>VIEWS
1.18 cvs 2817: Full_text, Table_of_contents, Formulas;</pre>
1.30 cvs 2818:
2819: <p>The contents of these views are specified in the presentation rules of
2820: the schema.</p>
1.18 cvs 2821: </blockquote>
2822: </div>
1.1 cvs 2823:
1.18 cvs 2824: <div class="subsection">
1.30 cvs 2825: <h3><a name="sectc423">Print Views</a></h3>
1.1 cvs 2826:
1.30 cvs 2827: <p>When editing a document, each view is presented in a different window. In
1.18 cvs 2828: addition to the views specified by the <tt>VIEWS</tt> instruction, the user
1.1 cvs 2829: can display the associated elements with one window for each type of
1.18 cvs 2830: associated element.</p>
1.30 cvs 2831:
2832: <p>When printing a document, it is possible to print any number of views,
2833: chosen from among all the views which the editor can display (views in the
2834: strict sense or associated elements). Print views, as well as the order in
2835: which they must be printed, are indicated by the <tt>PRINT</tt> instruction.
2836: It appears after the <tt>VIEWS</tt> instruction and is formed of the keyword
1.18 cvs 2837: <tt>PRINT</tt> followed by the ordered list of print view names. The print
1.1 cvs 2838: view names are separated by commas and followed by a semi-colon. A print view
1.18 cvs 2839: name is either a view name declared in the <tt>VIEWS</tt> instruction or the
1.1 cvs 2840: name of an associated element type (with an ``s'' added to the end). The
1.18 cvs 2841: associated element must have been declared in the <tt>ASSOC</tt> section of
2842: the structure schema.</p>
2843: <pre> 'PRINT' PrintViewSeq
1.30 cvs 2844: PrintViewSeq = PrintView < ',' PrintView > ';' .
1.18 cvs 2845: PrintView = ViewID / ElemID .</pre>
1.30 cvs 2846:
2847: <p>If the <tt>PRINT</tt> instruction is absent, the printing program will
2848: print only the principal view (the first view specified by the <tt>VIEWS</tt>
1.18 cvs 2849: instruction or the single, unnamed view when there is no <tt>VIEWS</tt>
2850: instruction).</p>
1.30 cvs 2851:
1.18 cvs 2852: <blockquote class="example">
1.30 cvs 2853: <p><strong>Example:</strong></p>
2854:
2855: <p>Consider a Report presentation using the view declarations from the
2856: preceding example. Suppose we want to print the full text and table of
2857: contents views, but not the Formulas view, which is only useful when
2858: editing. In addition, suppose that we also want to print the bibliographic
2859: citations, which are associated elements (of type <tt>Citation</tt>). A
2860: sensible printing order would be to print the full text then the
2861: bibliography and finally the table of contents. To obtain this result when
2862: printing, the presentation schema would say:</p>
2863: <pre>PRINT
1.18 cvs 2864: Full_text, Citations, Table_of_contents;</pre>
2865: </blockquote>
2866: </div>
2867:
2868: <div class="subsection">
1.30 cvs 2869: <h3><a name="sectc424">Counters</a></h3>
1.18 cvs 2870:
1.30 cvs 2871: <p>A presentation has a <em>counter</em> for each type of number in the
1.1 cvs 2872: presentation. All counters, and therefore all types of numbers, used in the
1.18 cvs 2873: schema must be declared after the <tt>COUNTERS</tt> keyword.</p>
1.30 cvs 2874:
2875: <p>Each counter declaration is composed of a name identifying the counter
1.1 cvs 2876: followed by a colon and the counting function to be applied to the counter.
1.18 cvs 2877: The counter declaration ends with a semi-colon.</p>
1.30 cvs 2878:
2879: <p>The counting function indicates how the counter values will be calculated.
1.16 cvs 2880: Three types of counting functions are available. The first type is used to
2881: count the elements of a list or aggregate: it assigns to the counter the rank
1.18 cvs 2882: of the element in the list or aggregate. More precisely, the function</p>
2883: <pre>RANK OF ElemID [ LevelAsc ] [ INIT AttrID ]
2884: [ 'REINIT' AttrID ]</pre>
1.30 cvs 2885:
2886: <p>indicates that when an element creates, by a creation rule (see the <a
1.18 cvs 2887: href="#sectc4232"><tt>Create</tt> instructions</a>), a presentation box
1.5 cvs 2888: containing the counter value, this value is the rank of the creating element,
1.18 cvs 2889: if it is of type <tt>ElemID</tt>, otherwise the rank of the first element of
2890: type <tt>ElemID</tt> which encloses the creating element in the logical
2891: structure of the document.</p>
1.30 cvs 2892:
2893: <p>The type name can be preceded by a star in the special case where the
1.18 cvs 2894: structure schema defines an element of whose <tt>ElemID</tt> is the same as
2895: that of an <a href="#sectd3284">inclusion</a> without expansion or with
2896: partial expansion. To resolve this ambiguity, the <tt>ElemID</tt> alone
2897: refers to the type defined in the structure schema while the <tt>ElemID</tt>
2898: preceded by a star refers to the included type.</p>
1.30 cvs 2899:
2900: <p>The type name <tt>ElemID</tt> can be followed by an integer. That number
1.1 cvs 2901: represents the relative level, among the ancestors of the creating element, of
1.18 cvs 2902: the element whose rank is asked. If that relative level <i>n</i> is unsigned,
2903: the <i>n</i><sup>th</sup> element of type <tt>ElemID</tt> encountered when
1.1 cvs 2904: travelling the logical structure from the root to the creating element is
1.16 cvs 2905: taken into account. If the relative level is negative, the logical structure
2906: is travelled in the other direction, from the creating element to the
1.18 cvs 2907: root.</p>
1.30 cvs 2908:
2909: <p>The function can end with the keyword <tt>INIT</tt> followed by the name of
2910: a numeric attribute (and only a numeric attribute). Then, the rank of the
2911: first element of the list or aggregate is considered to be the value of this
1.1 cvs 2912: attribute, rather than the default value of 1, and the rank of the other
2913: elements is shifted accordingly. The attribute which determines the initial
1.18 cvs 2914: value is searched on the element itself and on its ancestors.</p>
1.30 cvs 2915:
2916: <p>The function can end with the keyword <tt>REINIT</tt> followed by the name
2917: of a numeric attribute (and only a numeric attribute). Then, if an element to
2918: be counted has this attribute, the counter value for this element is the
1.1 cvs 2919: attribute value and the following elements are numbered starting from this
1.18 cvs 2920: value.</p>
1.30 cvs 2921:
2922: <p>When the <tt>RANK</tt> function is written</p>
1.18 cvs 2923: <pre>RANK OF Page [ ViewID ] [ INIT AttrID ]</pre>
1.30 cvs 2924:
2925: <p>(<tt>Page</tt>is a keyword of the P language), the counter takes as its
2926: value the number of the page on which the element which creates the
2927: presentation box containing the number appears. This is done as if the pages
2928: of the document form a list for each view. The counter only takes into
2929: account the pages of the relevant view, that is the view displaying the
2930: presentation box whose contents take the value of the number. However, if the
2931: keyword <tt>Page</tt> is followed by the name of a view (between parentheses),
2932: it is the pages of that view that are taken into account. As in the preceding
2933: form, the <tt>RANK</tt> function applied to pages can end with the
2934: <tt>INIT</tt> keyword followed by the name of a numeric attribute which sets
2935: the value of the first page's number. This attribute must be a local
2936: attribute of the document itself, and not of one of its components.</p>
2937:
2938: <p>The second counting function is used to count the occurrences of a certain
1.18 cvs 2939: element type in a specified context. The instruction</p>
2940: <pre>SET n ON Type1 ADD m ON Type2 [ INIT AttrID ]</pre>
1.30 cvs 2941:
2942: <p>says that when the document is traversed from beginning to end (in the
2943: order induced by the logical structure), the counter is assigned the value
1.18 cvs 2944: <tt>n</tt> each time an element of type <tt>Type1</tt> is encountered, no
2945: matter what the current value of the counter, and the value <tt>m</tt> is
2946: added to the current value of the counter each time an element of type
2947: <tt>Type2</tt> is encountered.</p>
1.30 cvs 2948:
2949: <p>As with the <tt>RANK</tt> function, the type names can be preceded by a
2950: star to resolve the ambiguity of included elements.</p>
2951:
2952: <p>If the function ends with the keyword <tt>INIT</tt> followed by the name of
2953: an attribute and if the document possesses this attribute, the value of this
1.18 cvs 2954: attribute is used in place of <tt>n</tt>. The attribute must be numeric. It
2955: is searched on the element itself and on its ancestors.</p>
1.30 cvs 2956:
2957: <p>This function can also be used with the <tt>Page</tt> keyword in the place
2958: of <tt>Type1</tt> or <tt>Type2</tt>. In the first case, the counter is
1.18 cvs 2959: reinitialized on each page with the value <tt>n</tt>, while in the second
2960: case, it is incremented by <tt>m</tt> on each page. As with the preceding
2961: counting function, the word <tt>Page</tt> can be followed by a name between
1.1 cvs 2962: parentheses. In this case, the name specifies a view whose pages are taken
1.18 cvs 2963: into account.</p>
1.30 cvs 2964:
2965: <p>The definition of a counter can contain several <tt>SET</tt> functions and
1.18 cvs 2966: several <tt>ADD</tt> functions, each with a different value. The total number
2967: of counting functions must not be greater than 6.</p>
1.30 cvs 2968:
2969: <p>The third counting function is used to count the elements of a certain type
1.16 cvs 2970: encountered when travelling from the creating element to the root of the
2971: logical structure. The creating element is included if it is of that type.
1.18 cvs 2972: That function is written</p>
2973: <pre>RLEVEL OF Type</pre>
1.30 cvs 2974:
2975: <p>where <tt>Type</tt> represents the type of the elements to be counted.</p>
2976:
2977: <p>The formal definition of counter declarations is:</p>
1.18 cvs 2978: <pre> 'COUNTERS' CounterSeq
1.30 cvs 2979: CounterSeq = Counter < Counter > .
1.1 cvs 2980: Counter = CounterID ':' CounterFunc ';' .
2981: CounterID = NAME .
2982: CounterFunc = 'RANK' 'OF' TypeOrPage [ SLevelAsc ]
1.16 cvs 2983: [ 'INIT' AttrID ] [ 'REINIT' AttrID ] /
1.30 cvs 2984: SetFunction < SetFunction >
2985: AddFunction < AddFunction >
1.16 cvs 2986: [ 'INIT' AttrID ] /
2987: 'RLEVEL' 'OF' ElemID .
1.1 cvs 2988: SLevelAsc = [ '-' ] LevelAsc .
2989: LevelAsc = NUMBER .
2990: SetFunction = 'SET' CounterValue 'ON' TypeOrPage .
2991: AddFunction = 'ADD' CounterValue 'ON' TypeOrPage .
2992: TypeOrPage = 'Page' [ '(' ViewID ')' ] /
1.16 cvs 2993: [ '*' ] ElemID .
1.18 cvs 2994: CounterValue = NUMBER .</pre>
1.30 cvs 2995:
1.18 cvs 2996: <blockquote class="example">
1.30 cvs 2997: <p><strong>Example:</strong></p>
2998:
2999: <p>If the body of a chapter is defined as a sequence of sections in the
3000: structure schema:</p>
3001: <pre>Chapter_body = LIST OF (Section =
1.1 cvs 3002: BEGIN
3003: Section_Title = Text;
3004: Section_Body = Paragraphs;
3005: END
1.18 cvs 3006: );</pre>
1.30 cvs 3007:
3008: <p>the section counter is declared:</p>
3009: <pre>SectionCtr : RANK OF Section;</pre>
3010:
3011: <p>and the display of the section number before the section title is
3012: obtained by a <a href="#sectc4232"><tt>CreateBefore</tt> rule</a> attached
3013: the <tt>Section_Title</tt> type, which creates a presentation box whose
3014: content is the value of the <tt>SectionCtr</tt> counter (see the <a
3015: href="#sectc4231"><tt>Content</tt> instruction</a>).</p>
3016:
3017: <p>In order to number the formulas separately within each chapter, the
3018: formula counter is declared:</p>
3019: <pre>FormulaCtr : SET 0 ON Chapter ADD 1 ON Formula;</pre>
3020:
3021: <p>and the display of the formula number in the right margin, alongside each
3022: formula, is obtained by a <tt>CreateAfter</tt> instruction attached to the
3023: <tt>Formula</tt> type, which creates a presentation box whose content is the
3024: value of the <tt>FormulaCtr</tt> counter.</p>
3025:
3026: <p>To number the page chapter by chapter, with the first page of each
3027: chapter having the number 1, the counter definition would be</p>
3028: <pre>ChapterPageCtr : SET 0 ON Chapter ADD 1 ON Page;</pre>
3029:
3030: <p>If there is also a chapter counter</p>
3031: <pre>ChapterCtr : RANK OF Chapter;</pre>
3032:
3033: <p>the <a href="#sectc4231">content</a> of a presentation box created at the
3034: top of each page could be defined as:</p>
3035: <pre>Content : (VALUE(ChapterCtr, URoman) TEXT '-'
1.18 cvs 3036: VALUE(ChapterPageCtr, Arabic));</pre>
1.30 cvs 3037:
3038: <p>Thus, the presentation box contains the number of the chapter in
3039: upper-case roman numerals followed by a hyphen and the number of the page
3040: within the chapter in arabic numerals.</p>
1.18 cvs 3041: </blockquote>
1.30 cvs 3042:
1.18 cvs 3043: <blockquote class="example">
1.30 cvs 3044: <p><strong>Example:</strong></p>
3045:
3046: <p>To count tables and figures together in a document of the chapter type, a
3047: counter could be defined using:</p>
3048: <pre>CommonCtr : SET 0 ON Chapter ADD 1 ON Table
1.18 cvs 3049: ADD 1 ON Figure;</pre>
3050: </blockquote>
3051: </div>
1.1 cvs 3052:
1.18 cvs 3053: <div class="subsection">
1.30 cvs 3054: <h3><a name="sectc425">Presentation constants</a></h3>
1.1 cvs 3055:
1.30 cvs 3056: <p>Presentation constants are used in the definition of the content of
1.18 cvs 3057: presentation boxes. This content is used in <a href="#sectc426">variable
3058: definitions</a> and in the <a href="#sectc4231"><tt>Content</tt> rule</a>. The
1.1 cvs 3059: only presentation constants which can be used are character strings,
1.2 cvs 3060: mathematical symbols, graphical elements, and pictures, that is to say, base
1.18 cvs 3061: elements.</p>
1.30 cvs 3062:
3063: <p>Constants can be defined directly in the variables or presentation boxes
1.18 cvs 3064: (<tt>Content</tt> rule) which use them. But it is only necessary them to
1.1 cvs 3065: declare once, in the constant declaration section, even though they are used
3066: in many variables or boxes. Thus, each declared constant has a name, which
3067: allows it to be designated whenever it is used, a type (one of the four base
3068: types) and a value (a character string or a single character for mathematical
1.18 cvs 3069: symbols and graphical elements).</p>
1.30 cvs 3070:
3071: <p>The constant declarations appear after the keyword <tt>CONST</tt>. Each
1.1 cvs 3072: declaration is composed of the name of the constant, an equals sign, a keyword
1.18 cvs 3073: representing its type (<tt>Text</tt>, <tt>Symbol</tt>, <tt>Graphics</tt> or
3074: <tt>Picture</tt>) and the string representing its value. A semi-colon
3075: terminates each declaration.</p>
1.30 cvs 3076:
3077: <p>In the case of a character string, the keyword <tt>Text</tt> can be
3078: followed by the name of an alphabet (for example, <tt>Greek</tt> or
3079: <tt>Latin</tt>) in which the constant's text should be expressed. If the
3080: alphabet name is absent, the Latin alphabet is used. When the alphabet name
3081: is present, only the first letter of the alphabet name is interpreted. Thus,
3082: the words <tt>Greek</tt> and <tt>Grec</tt> designate the same alphabet. In
3083: current versions of Thot, only the Greek and Latin alphabets are
3084: available.</p>
1.18 cvs 3085: <pre> 'CONST' ConstSeq
1.30 cvs 3086: ConstSeq = Const < Const > .
1.1 cvs 3087: Const = ConstID '=' ConstType ConstValue ';' .
3088: ConstID = NAME .
3089: ConstType ='Text' [ Alphabet ] / 'Symbol' /
3090: 'Graphics' / 'Picture' .
3091: ConstValue = STRING .
1.18 cvs 3092: Alphabet = NAME .</pre>
1.30 cvs 3093:
3094: <p>For character strings in the Latin alphabet (ISO Latin-1 character set),
1.1 cvs 3095: characters having codes higher than 127 (decimal) are represented by their
1.18 cvs 3096: code in octal.</p>
1.30 cvs 3097:
3098: <p>In the case of a symbol or graphical element, the value only contains a
3099: single character, between apostrophes, which indicates the form of the element
3100: which must be drawn in the box whose content is the constant. The symbol or
1.1 cvs 3101: graphical element takes the dimensions of the box, which are determined by the
1.18 cvs 3102: <tt>Height</tt> and <tt>Width</tt> rules. See <a href="#sectb72">table of
3103: codes</a> for the symbols and graphical elements.</p>
1.30 cvs 3104:
1.18 cvs 3105: <blockquote class="example">
1.30 cvs 3106: <p><strong>Example:</strong></p>
3107:
3108: <p>The constants ``Summary:'' and fraction bar, which were described
3109: earlier, are declared:</p>
3110: <pre>CONST
1.1 cvs 3111: SummaryConst = Text 'Summary:';
1.18 cvs 3112: Bar = Graphics 'h';</pre>
3113: </blockquote>
3114: </div>
1.1 cvs 3115:
1.18 cvs 3116: <div class="subsection">
1.30 cvs 3117: <h3><a name="sectc426">Variables</a></h3>
1.1 cvs 3118:
1.30 cvs 3119: <p>Variables permit the definition of computed content for presentation boxes.
3120: A variable is associated with a presentation box by a <tt>Content</tt> rule;
3121: but before being used in a <tt>Content</tt> rule, a variable can be defined in
3122: the <tt>VAR</tt> section. It is also possible to define a variable at the
3123: time of its use in a <tt>Content</tt> rule, as can be done with a
3124: constant.</p>
3125:
3126: <p>A variable has a name and a value which is a character string resulting
3127: from the concatenation of the values of a sequence of functions. Each
3128: variable declaration is composed of the variable name followed by a colon and
3129: the sequence of functions which produces its value, separated by spaces. Each
1.18 cvs 3130: declaration is terminated by a semi-colon.</p>
3131: <pre> 'VAR' VarSeq
1.30 cvs 3132: VarSeq = Variable < Variable > .
1.1 cvs 3133: Variable = VarID ':' FunctionSeq ';' .
3134: VarID = NAME .
1.30 cvs 3135: FunctionSeq = Function < Function > .</pre>
3136:
3137: <p>Several functions are available. The first two return, in the form of a
1.18 cvs 3138: character string, the current date. <tt>DATE</tt> returns the date in
3139: English, while <tt>FDATE</tt> returns the date in french.</p>
1.30 cvs 3140:
3141: <p>Two other functions, <tt>DocName</tt> and <tt>DirName</tt>, return the
1.18 cvs 3142: document name and the directory where the document is stored.</p>
1.30 cvs 3143:
3144: <p>Function <tt>ElemName</tt> returns the type of the element which created
3145: the presentation box whose contents are the variable.</p>
3146:
3147: <p>Another function simply returns the value of a presentation constant. For
3148: any constant declared in the <tt>CONST</tt> section, it is sufficient to give
3149: the name of the constant. Otherwise, the type and value of the constant must
3150: be given, using the same form as in a <a href="#sectc425">constant
1.18 cvs 3151: declaration</a>. If the constant is not of type text, (types <tt>Symbol</tt>,
3152: <tt>Graphics</tt> or <tt>Picture</tt>), it must be alone in the variable
3153: definition; only constants of type <tt>Text</tt> can be mixed with other
3154: functions.</p>
1.30 cvs 3155:
3156: <p>It is also possible to obtain the value of an attribute, simply by
3157: mentioning the attribute's name. The value of this function is the value of
3158: the attribute for the element which created the presentation box whose
3159: contents are the variable. If the creating element does not have the
3160: indicated attribute, the value is an empty string. In the case of a numeric
3161: attribute, the attribute is translated into a decimal number in arabic
3162: numerals. If another form is desired, the <tt>VALUE</tt> function must be
3163: used.</p>
3164:
3165: <p>The last available function returns, as a character string, the value of a
1.1 cvs 3166: counter, an attribute or a page number. This value can be presented in
1.18 cvs 3167: different styles. The keyword <tt>VALUE</tt> is followed (between
1.1 cvs 3168: parentheses) by the name of the counter, the name of the attribute, or the
1.18 cvs 3169: keyword <tt>PageNumber</tt> and the desired style, the two parameters being
1.1 cvs 3170: separated by a comma. The style is a keyword which indicates whether the
1.18 cvs 3171: value should be presented in arabic numerals (<tt>Arabic</tt>), lower-case
3172: roman numerals (<tt>LRoman</tt>), or upper-case roman numerals
3173: (<tt>URoman</tt>), or by an upper-case letter (<tt>Uppercase</tt>) or
3174: lower-case letter (<tt>Lowercase</tt>).</p>
1.30 cvs 3175:
3176: <p>For a page counter, the keyword <tt>PageNumber</tt> can be followed,
3177: between parentheses, by the name of the view from which to obtain the page
3178: number. By default, the first view declared in the <tt>VIEWS</tt> section is
3179: used. The value obtained is the number of the page on which is found the
3180: element that is using the variable in a <tt>Content</tt> rule.</p>
3181:
3182: <p>For an ordinary counter, the name of the counter can be preceded by the
1.18 cvs 3183: keyword <tt>MaxRangeVal</tt> or <tt>MinRangeVal</tt>. These keywords mean
1.1 cvs 3184: that the value returned by the function is the maximum (minimum resp.) value
3185: taken by the counter in the whole document, not the value for the element
1.18 cvs 3186: concerned by the function.</p>
3187: <pre> Function = 'DATE' / 'FDATE' /
1.1 cvs 3188: 'DocName' / 'DirName' /
3189: 'ElemName' / 'AttributeName' /
3190: ConstID / ConstType ConstValue /
3191: AttrID /
3192: 'VALUE' '(' PageAttrCtr ','
3193: CounterStyle ')' .
1.6 cvs 3194: PageAttrCtr = 'PageNumber' [ '(' ViewID ')' ] /
1.1 cvs 3195: [ MinMax ] CounterID / AttrID .
3196: CounterStyle = 'Arabic' / 'LRoman' / 'URoman' /
3197: 'Uppercase' / 'Lowercase' .
1.18 cvs 3198: MinMax = 'MaxRangeVal' / 'MinRangeVal' .</pre>
1.30 cvs 3199:
1.18 cvs 3200: <blockquote class="example">
1.30 cvs 3201: <p><strong>Example:</strong></p>
3202:
3203: <p>To make today's date appear at the top of the first page of a report, a
3204: <a href="#sectc4232"><tt>CREATE</tt> rule</a> associated with the
3205: Report_Title element type generates a presentation box whose content
3206: (specified by the <tt>Content</tt> rule of that presentation box) is the
3207: variable:</p>
3208: <pre>VAR
1.18 cvs 3209: Todays_date : TEXT 'Version of ' DATE;</pre>
1.30 cvs 3210:
3211: <p>To produce, before each section title, the chapter number (in upper-case
3212: roman numerals) followed by the section number (in arabic numerals), two
3213: counters must be defined:</p>
3214: <pre>COUNTERS
1.1 cvs 3215: ChapterCtr : RANK OF Chapter;
1.18 cvs 3216: SectionCtr : RANK OF Section;</pre>
1.30 cvs 3217:
3218: <p>and the Section_Title element must create a presentation box whose
3219: content is the variable</p>
3220: <pre>VAR
1.1 cvs 3221: SectionNum : VALUE (ChapterCtr, URoman) TEXT '-'
1.18 cvs 3222: VALUE (SectionCtr, Arabic);</pre>
1.30 cvs 3223:
3224: <p>In order to make the page number on which each section begins appear in
3225: the table of contents view next to the section title, each Section_Title
3226: element must create a presentation box, visible only in the table of
3227: contents view, whose content is the variable:</p>
3228: <pre>VAR
1.1 cvs 3229: TitlePageNume :
1.18 cvs 3230: VALUE (PageNumber(Full_text), Arabic);</pre>
3231: </blockquote>
3232: </div>
1.1 cvs 3233:
1.18 cvs 3234: <div class="subsection">
1.30 cvs 3235: <h3><a name="sectc427">Default presentation rules</a></h3>
1.1 cvs 3236:
1.30 cvs 3237: <p>In order to avoid having to specify, for each element type defined in the
1.1 cvs 3238: structure schema, values for every one of the numerous presentation
1.34 cvs 3239: properties, the presentation schema allows the definition of a set of default
1.1 cvs 3240: presentation rules. These rules apply to all the boxes of the elements
3241: defined in the structure schema and to the presentation boxes and page layout
3242: boxes defined in the presentation schema. Only rules which differ from these
1.18 cvs 3243: default need to be specified in other sections of the presentation schema.</p>
1.30 cvs 3244:
3245: <p>For the primary view, the default rules can define every presentation
1.34 cvs 3246: property, but not the <a href="#presfunct">presentation functions</a> or the
1.18 cvs 3247: <a href="#sectc4223">linebreaking conditions</a> (the <tt>NoBreak1</tt>,
3248: <tt>NoBreak2</tt>, and <tt>Gather</tt> rules).</p>
1.30 cvs 3249:
3250: <p>In a presentation schema, the default presentation rules section is
3251: optional; in this case, the <tt>DEFAULT</tt> keyword is also absent and the
3252: following rules are considered to be the default rules:</p>
1.26 cvs 3253: <pre> Visibility: Enclosing =;
3254: VertRef: * . Left;
3255: HorizRef: Enclosed . HRef;
3256: Height: Enclosed . Height;
3257: Width: Enclosed . Width;
3258: VertPos: Top = Previous . Bottom;
3259: HorizPos: Left = Enclosing . Left;
3260: MarginTop: 0;
3261: MarginRight: 0;
3262: MarginBottom: 0;
3263: MarginLeft: 0;
3264: PaddingTop: 0;
3265: PaddingRight: 0;
3266: PaddingBottom: 0;
3267: PaddingLeft: 0;
3268: BorderTopWidth: 0;
3269: BorderRightWidth: 0;
3270: BorderBottomWidth: 0;
3271: BorderLeftWidth: 0;
3272: BorderTopColor: Foreground;
3273: BorderRightColor: Foreground;
3274: BorderBottomColor: Foreground;
3275: BorderLeftColor: Foreground;
3276: BorderTopStyle: None;
3277: BorderRightStyle: None;
3278: BorderBottomStyle: None;
3279: BorderLeftStyle: None;
3280: VertOverflow: No;
3281: HorizOverflow: No;
3282: Size: Enclosing =;
3283: Style: Enclosing =;
3284: Weight: Enclosing =;
3285: Font: Enclosing =;
3286: Underline: Enclosing =;
3287: Thickness: Enclosing =;
3288: Indent: Enclosing =;
3289: LineSpacing: Enclosing =;
3290: Adjust: Enclosing =;
3291: Hyphenate: Enclosing =;
3292: PageBreak: Yes;
3293: LineBreak: Yes;
3294: InLine: Yes;
3295: Depth: 0;
3296: LineStyle: Enclosing =;
3297: LineWeight: Enclosing =;
3298: FillPattern: Enclosing =;
3299: Background: Enclosing =;
3300: Foreground: Enclosing =;</pre>
1.30 cvs 3301:
3302: <p>If other values are desired for the default rules, they must be defined
1.1 cvs 3303: explicitly in the default rules section. In fact, it is only necessary to
3304: define those default rules which differ from the ones above, since the rules
1.18 cvs 3305: above will be used whenever a rule is not explicitly named.</p>
1.30 cvs 3306:
3307: <p>Default rules for views other than the primary view can also be specified.
1.1 cvs 3308: Otherwise, the default rules for the primary views are applied to the other
1.18 cvs 3309: views.</p>
1.30 cvs 3310:
3311: <p>Default rules are expressed in the same way as <a
3312: href="#sectc4215">explicit rules for document elements</a>.</p>
1.18 cvs 3313: </div>
1.1 cvs 3314:
1.18 cvs 3315: <div class="subsection">
1.30 cvs 3316: <h3><a name="sectc428">Presentation and page layout boxes</a></h3>
1.1 cvs 3317:
1.30 cvs 3318: <p>The presentation process uses elements which are not part of the logical
1.1 cvs 3319: structure of the document, such as pages (which are the page layout boxes) or
3320: alternatively, rules, numbers, or words introducing certain parts of the
3321: document, such as ``Summary'', ``Appendices'', ``Bibliography'', etc. (which
1.18 cvs 3322: are presentation boxes).</p>
1.30 cvs 3323:
3324: <p>After the word <tt>BOXES</tt>, each presentation or page layout box is
3325: defined by its name and a sequence of presentation rules which indicate how
3326: they must be displayed. These rules are the same as those which define the
3327: boxes associated with element of the logical structure of the document, with a
1.18 cvs 3328: single exception, the <a href="#sectc4231"><tt>Content</tt> rule</a> which is
1.1 cvs 3329: used only to specify the content of presentation boxes. The content of boxes
3330: associated with elements of the document structure is defined in each document
3331: or object and thus is not specified in the presentation schema, which applies
1.18 cvs 3332: to all documents or objects of a class.</p>
1.30 cvs 3333:
3334: <p>Among the rules which define a presentation box, certain ones can refer to
1.1 cvs 3335: another presentation box (for example, in their positional rules). If the
3336: designated box is defined after the box which designates it, a
1.18 cvs 3337: <tt>FORWARD</tt> instruction followed by the name of the designated box must
3338: appear before the designation.</p>
3339: <pre> 'BOXES' BoxSeq
1.30 cvs 3340: BoxSeq = Box < Box > .
1.1 cvs 3341: Box ='FORWARD' BoxID ';' /
3342: BoxID ':' ViewRuleSeq .
1.18 cvs 3343: BoxID = NAME .</pre>
3344: </div>
1.1 cvs 3345:
1.18 cvs 3346: <div class="subsection">
1.30 cvs 3347: <h3><a name="sectc429">Presentation of structured elements</a></h3>
1.1 cvs 3348:
1.30 cvs 3349: <p>After the words <tt>RULES</tt>, the presentation schema gives the
3350: presentation rules that apply to the elements whose types are defined in the
3351: structure schema. Only those rules which differ from the <a
1.18 cvs 3352: href="#sectc427">default</a> must be specified in the <tt>RULES</tt>
3353: section.</p>
1.30 cvs 3354:
3355: <p>The rule definitions for each element type are composed of the name of the
1.1 cvs 3356: element type (as specified in the structure schema) followed by a colon and
1.18 cvs 3357: the set of rules specific to that type.</p>
1.30 cvs 3358:
3359: <p>The type name can be preceded by a star in the special case where the
1.18 cvs 3360: structure schema defines an <a href="#sectd3284">inclusion</a> without
1.1 cvs 3361: expansion (or with partial expansion) of a type with the same name as an
1.18 cvs 3362: element of defined in the structure schema.</p>
1.30 cvs 3363:
3364: <p>In the case where the element is a <a href="#sectd3285">mark pair</a>, but
1.18 cvs 3365: only in this case, the type name can be preceded by the keywords
3366: <tt>First</tt> or <tt>Second</tt>. These keywords indicate whether the rules
3367: that follow apply to the first or second mark of the pair.</p>
3368: <pre> 'RULES' PresentSeq
1.30 cvs 3369: PresentSeq = Present < Present > .
1.6 cvs 3370: Present = [ '*' ] [ FirstSec ] ElemID ':'
3371: ViewRuleSeq .
1.18 cvs 3372: FirstSec = 'First' / 'Second' .</pre>
1.30 cvs 3373:
3374: <p>A presentation schema can define presentation rules for base elements,
3375: which are defined implicitly in the structure schemas. In the English version
3376: of the presentation schema compiler, the base type names are the same as in
3377: the S language, but they are terminated by the <tt>_UNIT</tt> suffix:
1.18 cvs 3378: <tt>TEXT_UNIT</tt>, <tt>PICTURE_UNIT</tt>, <tt>SYMBOL_UNIT</tt>,
3379: <tt>GRAPHICS_UNIT</tt>. The base type names are written in upper-case
3380: letters.</p>
3381: </div>
3382:
3383: <div class="subsection">
1.30 cvs 3384: <h3><a name="sectc4210">Logical attribute presentation</a></h3>
1.18 cvs 3385:
1.30 cvs 3386: <p>After the keyword <tt>ATTRIBUTES</tt>, all attributes which are to have
3387: some effect on the presentation of the element to which they are attached must
3388: be mentioned, along with the corresponding presentation rules. This is true
3389: for both global attributes (which can be attached to all element types) and
3390: local attributes (which can only be attached to certain element types).</p>
3391:
3392: <p>Also mentioned in this section are attributes which imply an effect on
1.1 cvs 3393: elements in the subtree of the element to which they are attached. The
3394: presentation of these descendants can be modified as a function of the value
3395: of the attribute which they inherit, just as if it was attached to them
1.18 cvs 3396: directly.</p>
1.30 cvs 3397:
3398: <p>The specification for each attribute includes the attribute's name,
3399: followed by an optional value specification and, after a colon, a set of
3400: rules. The set of rules must contain at least one rule.</p>
3401:
3402: <p>When there is no value specification, the rules are applied to all elements
1.1 cvs 3403: which carry the attribute, no matter what their value. When the rules must
3404: only apply when the attribute has certain values, these values must be
1.18 cvs 3405: specified. Thus, the same attribute can appear in the <tt>ATTRIBUTES</tt>
1.1 cvs 3406: section several times, with each appearance having a different value
3407: specification. However, reference attributes never have a value specification
1.18 cvs 3408: and, as a result, can only appear once in the <tt>ATTRIBUTES</tt> section.</p>
1.30 cvs 3409:
3410: <p>To specify that the presentation rules apply to some of the descendants of
3411: the element having the attribute, the name of the affected element type is
3412: given, between parentheses, after the attribute name. This way, the
3413: presentation rules for the attribute will be applied to the element having the
3414: attribute, if it is of the given type, and to all of its descendants of the
3415: given type. In the case where this type is a <a href="#sectd3285">mark
3416: pair</a>, but only in this case, the type name can be preceded by the keywords
3417: <tt>First</tt> or <tt>Second</tt>. These keywords indicate whether the rules
3418: that follow apply to the first or second mark of the pair. If the rule must
3419: apply to several different element types, the specification must be repeated
3420: for each element type.</p>
3421:
3422: <p>The specification of values for which the presentation rules will be
3423: applied varies according to the type of the attribute:</p>
1.18 cvs 3424: <dl>
1.30 cvs 3425: <dt>numeric attribute</dt>
3426: <dd>If the rules are to apply for one value of the attribute, then the
3427: attribute name is followed by an equals sign and this value. If the
3428: rules are to apply for all values less than (or greater than) a
3429: threshold value, non-inclusive, the attribute name followed by a '<'
3430: sign (or a '>' sign, respectively) and the threshold value. If the
3431: rules must apply to a range of values, the attribute name is followed by
3432: the word '<tt>IN</tt>' and the two bounds of the range, enclosed in
3433: brackets and separated by two periods ('<tt>..</tt>'). In the case of
3434: ranges, the values of the bounds are included in the range.
3435: <p>The threshold value in the comparisons can be the value of an
3436: attribute attached to an ancestor element. In this case, the attribute
3437: name is given instead of a constant value.</p>
3438: <p>It is also possible to write rules which apply only when a comparison
3439: between two different attributes of the element's ancestors is true. In
3440: this case, the first attribute name is followed by a comparison keyword
3441: and the name of the second attribute. The comparison keywords are
3442: <tt>EQUAL</tt> (simple equality), <tt>LESS</tt> (non-inclusive less
3443: than), and <tt>GREATER</tt> (non-inclusive greater than).</p>
3444: </dd>
3445: <dt>text attribute</dt>
3446: <dd>If the rules are to apply for one value of the attribute, then the
3447: attribute name is followed by an equals sign and this value.</dd>
3448: <dt>reference attribute</dt>
3449: <dd>There is never a value specification; the rules apply no matter what
3450: element is designated by the attribute.</dd>
3451: <dt>enumerated attribute</dt>
3452: <dd>If the rules are to apply for one value of the attribute, then the
3453: attribute name is followed by an equals sign and this value.</dd>
1.18 cvs 3454: </dl>
1.30 cvs 3455:
3456: <p>The order in which the rules associated with a numeric attribute are
3457: defined is important. When multiple sets of rules can be applied, the first
3458: set declared is the one used.</p>
3459:
3460: <p>Rules for attributes have priority over both default rules and rules
1.1 cvs 3461: associated with element types. The attribute rules apply to the element to
3462: which the attribute is attached. It is the rules which apply to the
3463: surrounding elements (and especially to the descendants) which determine the
3464: effect of the attribute rules on the environment ( and especially on the
1.18 cvs 3465: terminal elements of the structure).</p>
3466: <pre> 'ATTRIBUTES' PresAttrSeq
1.30 cvs 3467: PresAttrSeq = PresAttr < PresAttr > .
1.1 cvs 3468: PresAttr = AttrID [ '(' [ FirstSec ] ElemID ')' ]
3469: [ AttrRelation ] ':' ViewRuleSeq .
3470: AttrID = NAME .
3471: AttrRelation ='=' AttrVal /
1.30 cvs 3472: '>' [ '-' ] MinValue /
1.1 cvs 3473: '<' [ '-' ] MaxValue /
3474: 'IN' '[' [ '-' ] LowerBound '..'
3475: [ '-' ] UpperBound ']' /
3476: 'GREATER' AttrID /
3477: 'EQUAL' AttrID /
3478: 'LESS' AttrID .
3479: AttrVal = [ '-' ] EqualNum / EqualText /
3480: AttrValue .
3481: MinValue = NUMBER .
3482: MaxValue = NUMBER .
3483: LowerBound = NUMBER .
3484: UpperBound = NUMBER.
3485: EqualNum = NUMBER .
3486: EqualText = STRING .
1.18 cvs 3487: AttrValue = NAME .</pre>
1.30 cvs 3488:
3489: <p>In presentation rules associated with a numeric attribute (and only in such
1.1 cvs 3490: rules), the attribute name can be used in place of a numeric value. In this
3491: case, the value of the attribute is used in the application of the rule. Thus,
3492: the attribute can represent a relation between the size of two boxes, the
3493: height and width of a box, the height of an area where page breaks are
3494: prohibited, the distance between two boxes, the position of the reference axis
3495: of a box, the interline spacing, the indentation of the first line, the
1.18 cvs 3496: visibility, the depth (z-order), or the character set.</p>
1.30 cvs 3497:
3498: <p>The presentation rules associated with reference attributes, it is possible
3499: to use the element designated by the attribute as a reference box in a
3500: positional or extent rule. This element is represented in the <a
1.18 cvs 3501: href="#sectc4218">position</a> or <a href="#sectc4219">extent</a> rule by the
3502: keyword <tt>Referred</tt>.</p>
1.30 cvs 3503:
1.18 cvs 3504: <blockquote class="example">
1.30 cvs 3505: <p><strong>Example:</strong></p>
3506:
3507: <p>In all structure schemas, there is a global Language attribute defined as
3508: follows:</p>
3509: <pre>ATTR
1.18 cvs 3510: Language = TEXT;</pre>
1.30 cvs 3511:
3512: <p>The following rules would make French text be displayed in roman
3513: characters and English text be displayed in italics:</p>
3514: <pre>ATTRIBUTES
1.1 cvs 3515: Language = 'French' :
1.6 cvs 3516: Style : Roman;
1.1 cvs 3517: Language = 'English' :
1.18 cvs 3518: Style : Italics;</pre>
1.30 cvs 3519:
3520: <p>Using these rules, when the user puts the Language attribute with the
3521: value 'English' on the summary of a document, every character string
3522: (terminal elements) contained in the summary are displayed in italics. See
3523: the <a href="#sectd42252"><tt>Style</tt> rule</a>.</p>
1.18 cvs 3524: </blockquote>
1.30 cvs 3525:
1.18 cvs 3526: <blockquote class="example">
1.30 cvs 3527: <p><strong>Example:</strong></p>
3528:
3529: <p>A numeric attribute representing the importance of the part of the
3530: document to which it is attached can be defined:</p>
3531: <pre>ATTR
1.18 cvs 3532: Importance = INTEGER;</pre>
1.30 cvs 3533:
3534: <p>In the presentation schema, the importance of an element is reflected in
3535: the choice of character size, using the following rules.</p>
3536: <pre>ATTRIBUTES
1.1 cvs 3537: Importance < 2 :
3538: Size : 1;
3539: Importance IN [2..4] :
3540: Size : Importance;
3541: Importance = 10 :
3542: Size : 5;
1.30 cvs 3543: Importance > 4 :
1.18 cvs 3544: Size : 4;</pre>
1.30 cvs 3545:
3546: <p>Thus, the character size corresponds to the value of the Importance
3547: attribute; its value is</p>
3548: <ul>
3549: <li>the value of the Importance attribute when the value is between 2 and
3550: 4 (inclusive),</li>
3551: <li>1, when the value of the Importance attribute is less than 2,</li>
3552: <li>4, when the value of the Importance attribute is greater than 4,</li>
3553: <li>5, when the value of the Importance attribute is 10.</li>
3554: </ul>
3555:
3556: <p>The last case (value 5) must be defined before the case which handles all
3557: Importance values greater than 4, because the two rules are not disjoint and
3558: the first one defined will have priority. Otherwise, when the Importance
3559: attribute has value 10, the font size will be 4.</p>
1.18 cvs 3560: </blockquote>
1.30 cvs 3561:
1.18 cvs 3562: <blockquote class="example">
1.30 cvs 3563: <p><strong>Example:</strong></p>
3564:
3565: <p>Suppose the structure defines a list element which can have an attribute
3566: defining the type of list (numbered or not):</p>
3567: <pre>STRUCT
1.1 cvs 3568: list (ATTR list_type = enumeration, dash)
1.18 cvs 3569: = LIST OF (list_item = TEXT);</pre>
1.30 cvs 3570:
3571: <p>Then, the presentation schema could use the attribute placed on the list
3572: element to put either a dash or a number before the each element of the
3573: list:</p>
3574: <pre>ATTRIBUTES
1.1 cvs 3575: list_type (list_item) = enumeration :
3576: CreateBefore (NumberBox);
3577: list_type (list_item) = dash :
1.18 cvs 3578: CreateBefore (DashBox);</pre>
3579: </blockquote>
1.30 cvs 3580:
1.18 cvs 3581: <blockquote class="example">
1.30 cvs 3582: <p><strong>Example:</strong></p>
3583:
3584: <p>Suppose that two attributes are defined in the structure schema. The
3585: first is a numeric global attribute called ``version''. The other is a
3586: local attribute defined on the root of the document called
3587: ``Document_version'':</p>
3588: <pre>STRUCTURE Document
1.1 cvs 3589: ATTR
3590: version = INTEGER;
3591: STRUCT
3592: Document (ATTR Document_version = INTEGER) =
3593: BEGIN
3594: SomeElement ;
3595: ...
3596: SomeOtherElement ;
3597: END ;
1.18 cvs 3598: ...</pre>
1.30 cvs 3599:
3600: <p>These attributes can be used in the presentation schema to place change
3601: bars in the margin next to elements whose version attribute has a value
3602: equal to the Document_version attribute of the root and to place a star in
3603: margin of elements whose version attribute is less than the value of the
3604: root's Document_version attribute:</p>
3605: <pre>ATTRIBUTES
1.1 cvs 3606: version EQUAL Document_version :
3607: CreateBefore (ChangeBarBox) ;
3608: version LESS Document_version :
1.18 cvs 3609: CreateBefore (StarBox) ;</pre>
3610: </blockquote>
3611: </div>
1.1 cvs 3612:
1.18 cvs 3613: <div class="subsection">
1.30 cvs 3614: <h3><a name="sectc4212">Value transmission rules</a></h3>
1.1 cvs 3615:
1.30 cvs 3616: <p>The last section of a presentation schema, which is optional, serves to
1.1 cvs 3617: defines the way in which a document transmits certain values to its
1.18 cvs 3618: sub-documents. A sub-document is an document <a
3619: href="#inclusion">included</a> without expansion or with partial expansion.
1.1 cvs 3620: The primary document can transmit to its sub-documents the values of certain
3621: counters or the textual content of certain of its elements, as a function of
1.18 cvs 3622: their type.</p>
1.30 cvs 3623:
3624: <p>The sub-documents receive these values in attributes which must be defined
3625: in their structure schema as local attributes of the root element. The types
3626: of these attributes must correspond to the type of the value which they
3627: receive: numeric attributes for receiving the value of a counter, textual
3628: attributes for receiving the content of an element.</p>
3629:
3630: <p>In the structure schema of the primary document, there appears at the end,
1.18 cvs 3631: after the <tt>TRANSMIT</tt> keyword, a sequence of transmission rules. Each
1.1 cvs 3632: rule begins with the name of the counter to transmit or of the element type
3633: whose textual content will be transmitted. This name is followed by the
1.18 cvs 3634: keyword <tt>To</tt> and the name of the attribute of the sub-document to which
1.1 cvs 3635: the value is transmitted. The sub-document class is indicated between
3636: parentheses after the name of the attribute. The transmission rule ends with
1.18 cvs 3637: a semicolon.</p>
1.30 cvs 3638: <pre> TransmitSeq = Transmit < Transmit > .
1.1 cvs 3639: Transmit = TypeOrCounter 'To' ExternAttr
3640: '(' ElemID ')' ';' .
3641: TypeOrCounter = CounterID / ElemID .
1.18 cvs 3642: ExternAttr = NAME .</pre>
1.30 cvs 3643:
1.18 cvs 3644: <blockquote class="example">
1.30 cvs 3645: <p><strong>Example:</strong></p>
3646:
3647: <p>Consider a Book document class which includes instances of the Chapter
3648: document class. These classes might have the following schemas:</p>
3649: <pre>STRUCTURE Book
1.1 cvs 3650: STRUCT
3651: Book = BEGIN
3652: Title = Text;
3653: Body = LIST OF (Chapter INCLUDED);
3654: END;
3655: ...
3656:
3657: STRUCTURE Chapter
3658: STRUCT
3659: Chapter (ATTR FirstPageNum = Integer;
3660: ChapterNum = Integer;
3661: CurrentTitle = Text) =
1.6 cvs 3662: BEGIN
3663: ChapterTitle = Text;
3664: ...
3665: END;
1.18 cvs 3666: ...</pre>
1.30 cvs 3667:
3668: <p>Then the presentation schema for books could define chapter and page
3669: counters. The following transmission rules in the book presentation schema
3670: would transmit values for the three attributes defined at the root of each
3671: chapter sub-document.</p>
3672: <pre>PRESENTATION Book;
1.1 cvs 3673: VIEWS
3674: Full_text;
3675: COUNTERS
3676: ChapterCtr: Rank of Chapter;
3677: PageCtr: Rank of Page(Full_text);
3678: ...
3679: TRANSMIT
3680: PageCtr TO FirstPageNum(Chapter);
3681: ChapterCtr TO ChapterNum(Chapter);
3682: Title TO CurrentTitle(Chapter);
1.18 cvs 3683: END</pre>
1.30 cvs 3684:
3685: <p>Thus, each chapter included in a book can number its pages as a function
3686: of the number of pages preceding it in the book, can make the chapter's
3687: number appear before the number of each of its sections, or can place the
3688: title of the book at the top of each page.</p>
1.18 cvs 3689: </blockquote>
3690: </div>
1.1 cvs 3691:
1.18 cvs 3692: <div class="subsection">
1.30 cvs 3693: <h3><a name="sectc4213">Presentation rules</a></h3>
1.1 cvs 3694:
1.30 cvs 3695: <p>Whether defining the appearance of a presentation or page layout box, an
1.1 cvs 3696: element type, or an attribute value, the set of presentation rules that apply
1.18 cvs 3697: is always defined in the same way.</p>
1.30 cvs 3698:
3699: <p>Normally, a set of presentation rules is placed between the keywords
1.18 cvs 3700: <tt>BEGIN</tt> and <tt>END</tt>, the keyword <tt>END</tt> being followed by a
1.1 cvs 3701: semicolon. The first section of this block defines the rules that apply to
1.18 cvs 3702: the primary view, if the <a href="#sectc427">default rules</a> are not
1.1 cvs 3703: completely suitable. Next comes the rules which apply to specific other
3704: views, with a rule sequence for each view for which the default rules are not
3705: satisfactory. If the default rules are suitable for the non-primary views,
3706: there will not be any specific rules for these views. If there is only one
1.18 cvs 3707: rule which applies to all views then the keywords <tt>BEGIN</tt> and
3708: <tt>END</tt> need not appear.</p>
1.30 cvs 3709:
3710: <p>For each view, it is only necessary to specify those rules which differ
3711: from the default rules for the view, so that for certain views (or even all
3712: views), there may be no specific rules.</p>
3713:
3714: <p>The specific rules for a non-primary view are introduced by the <a
1.18 cvs 3715: name="inkeyword"><tt>IN</tt> keyword</a>, followed by the view name. The
3716: rules for that view follow, delimited by the keywords <tt>BEGIN</tt> and
3717: <tt>END</tt>, or without these two keywords when there is only one rule.</p>
1.30 cvs 3718:
3719: <p><strong>Note:</strong> the view name which follows the <tt>IN</tt> keyword
1.1 cvs 3720: must not be the name of the primary view, since the rules for that view are
1.18 cvs 3721: found before the rules for the other views.</p>
1.30 cvs 3722:
3723: <p>Within each block concerning a view, other blocks can appear, delimited by
3724: the same keywords <tt>BEGIN</tt> and <tt>END</tt>. Each of these blocks
3725: gathers the presentation rules that apply, for a given view, only when a given
1.1 cvs 3726: condition is satisfied. Each block is preceded by a condition introduced by
1.18 cvs 3727: the <tt>IF</tt> keyword. If such a conditional block contains only one rule,
3728: the keywords <tt>BEGIN</tt> and <tt>END</tt> can be omitted.</p>
1.30 cvs 3729:
3730: <p>Although the syntax allows any presentation rule to appear in a conditional
1.18 cvs 3731: block, only <a href="#sectc4232">creation rules</a> are allowed after any
3732: condition; other rules are allowed only after conditions <tt>Within</tt> and
1.1 cvs 3733: ElemID. In addition, the following rules cannot be conditional:
1.18 cvs 3734: <tt>PageBreak, LineBreak, Inline, Gather</tt>.</p>
1.30 cvs 3735:
3736: <p>For a given view, the rules that apply without any condition must appear
1.1 cvs 3737: before the first conditional block. If some rules apply only when none of the
3738: specified condition holds, they are grouped in a block preceded by the keyword
1.18 cvs 3739: <tt>Otherwise</tt>, and that block must appear after the last conditionnal
3740: block concerning the same view.</p>
1.30 cvs 3741: <pre> ViewRuleSeq = 'BEGIN' < RulesAndCond > < ViewRules >
1.1 cvs 3742: 'END' ';' /
3743: ViewRules / CondRules / Rule .
3744: RulesAndCond = CondRules / Rule .
3745: ViewRules = 'IN' ViewID CondRuleSeq .
1.30 cvs 3746: CondRuleSeq = 'BEGIN' < RulesAndCond > 'END' ';' /
1.1 cvs 3747: CondRules / Rule .
1.30 cvs 3748: CondRules = CondRule < CondRule >
1.1 cvs 3749: [ 'Otherwise' RuleSeq ] .
3750: CondRule = 'IF' ConditionSeq RuleSeq .
1.30 cvs 3751: RulesSeq = 'BEGIN' Rule < Rule > 'END' ';' /
1.18 cvs 3752: Rule .</pre>
1.30 cvs 3753:
1.18 cvs 3754: <blockquote class="example">
1.30 cvs 3755: <p><strong>Example:</strong></p>
3756:
3757: <p>The following rules for a report's title make the title visible in the
3758: primary view and invisible in the table of contents and in the formula views
3759: (see the <a href="#sectc4224"><tt>Visibility</tt> rule</a>).</p>
3760: <pre>Title : BEGIN
1.1 cvs 3761: Visibility : 1;
3762: ... {Other rules for the primary view}
3763: IN Table_of_contents
3764: Visibility : 0;
3765: IN Formulas
3766: Visibility : 0;
1.18 cvs 3767: END;</pre>
3768: </blockquote>
3769: </div>
1.1 cvs 3770:
1.18 cvs 3771: <div class="subsection">
1.30 cvs 3772: <h3><a name="sectc4214">Conditions applying to presentation rules</a></h3>
1.1 cvs 3773:
1.30 cvs 3774: <p>Many conditions can be applied to presentation rules. Conditions allow
1.1 cvs 3775: certain presentation rules to apply only in certain cases. These conditions
3776: can be based on the structural position of the element. They can be based on
3777: whether the element has references, and what type of references, whether the
1.33 cvs 3778: element has attributes, whether the element is empty or not, whether the
3779: element is the root of its document or not. They can also be based on the
3780: value of a counter.</p>
1.30 cvs 3781:
3782: <p>It is possible to specify several conditions which must all be true for the
1.18 cvs 3783: rules to apply.</p>
1.30 cvs 3784:
3785: <p>A set of conditions is specified by the <tt>IF</tt> keyword. This keyword
3786: is followed by the sequence of conditions, separated by the <tt>AND</tt>
3787: keyword. Each condition is specified by a keyword which defines the condition
3788: type. In some cases, the keyword is followed by other data, which specify the
3789: condition more precisely.</p>
3790:
3791: <p>An elementary condition can be negative; it is then preceded by the
1.18 cvs 3792: <tt>NOT</tt> keyword.</p>
1.30 cvs 3793:
3794: <p>When the presentation rule(s) controlled by the condition apply to a
3795: reference element or a reference attribute, an elementary condition can also
3796: apply to element referred by this reference. The <tt>Target</tt> keyword is
3797: used for that purpose. It must appear before the keyword defining the
3798: condition type.</p>
1.18 cvs 3799: <pre> CondRule ='IF' ConditionSeq RuleSeq .
1.30 cvs 3800: ConditionSeq = Condition < 'AND' Condition > .
1.1 cvs 3801: Condition = [ 'NOT' ] [ 'Target' ] ConditionElem .
3802: ConditionElem ='First' / 'Last' /
3803: [ 'Immediately' ] 'Within' [ NumParent ]
3804: ElemID [ ExtStruct ] /
3805: ElemID /
3806: 'Referred' / 'FirstRef' / 'LastRef' /
3807: 'ExternalRef' / 'InternalRef' / 'CopyRef' /
3808: 'AnyAttributes' / 'FirstAttr' / 'LastAttr' /
3809: 'UserPage' / 'StartPage' / 'ComputedPage' /
1.33 cvs 3810: 'Empty' / 'Root' /
1.1 cvs 3811: '(' [ MinMax ] CounterName CounterCond ')' /
3812: CondPage '(' CounterID ')' .
3813: NumParent = [ GreaterLess ] NParent .
1.30 cvs 3814: GreaterLess ='>' / '<' .
1.1 cvs 3815: NParent = NUMBER.
1.6 cvs 3816: ExtStruct ='(' ElemID ')' .
1.30 cvs 3817: CounterCond ='<' MaxCtrVal / '>' MinCtrVal /
1.1 cvs 3818: '=' EqCtrVal /
3819: 'IN' '[' ['-'] MinCtrBound '.' '.'
3820: ['-'] MaxCtrBound ']' .
3821: PageCond ='Even' / 'Odd' / 'One' .
3822: MaxCtrVal = NUMBER .
3823: MinCtrVal = NUMBER .
3824: EqCtrVal = NUMBER .
3825: MaxCtrBound = NUMBER .
1.18 cvs 3826: MinCtrBound = NUMBER .</pre>
1.1 cvs 3827:
1.18 cvs 3828: <div class="subsubsection">
3829: <h4><a name="sectd42141">Conditions based on the logical position of the
3830: element</a></h4>
1.30 cvs 3831:
3832: <p>The condition can be on the position of the element in the document's
3833: logical structure tree. It is possible to test whether the element is the
3834: first (<tt>First</tt>) or last (<tt>Last</tt>) among its siblings or if it is
3835: not the first (<tt>NOT First</tt>) or not the last (<tt>NOT Last</tt>). These
1.18 cvs 3836: conditions can be associated only with <a href="#sectc4232">creation
3837: rules</a>.</p>
1.30 cvs 3838:
1.33 cvs 3839: <p>It is possible to test if the element is the root of its document (keyword
3840: <code>Root</code>).</p>
3841:
1.30 cvs 3842: <p>It is also possible to test if the element is contained in an element of a
1.18 cvs 3843: given type (<tt>Within</tt>) or if it is not (<tt>NOT Within</tt>). The type
3844: is indicated after the keyword <tt>Within</tt>. If that element type is
1.1 cvs 3845: defined in a structure schema which is not the one which corresponds to the
3846: presentation schema, the type name of this element must be followed, between
1.18 cvs 3847: parentheses, by the name of the structure schema which defines it.</p>
1.30 cvs 3848:
3849: <p>If the keyword <tt>Within</tt> is preceded by <tt>Immediately</tt>, the
1.18 cvs 3850: condition is satisfied only if the <em>parent</em> element has the type
3851: indicated. If the word <tt>Immediately</tt> is missing, the condition is
3852: satisfied if any <em>ancestor</em> has the type indicated.</p>
1.30 cvs 3853:
3854: <p>An integer <i>n</i> can appear between the keyword <tt>Within</tt> and the
1.1 cvs 3855: type. It specifies the number of ancestors of the indicated type that must be
3856: present for the condition to be satisfied. If the keyword
1.18 cvs 3857: <tt>Immediately</tt> is also present, the <i>n</i> immediate ancestors of the
3858: element must have the indicated type. The integer <i>n</i> must be positive
1.30 cvs 3859: or zero. It can be preceded by <tt><</tt> or <tt>></tt> to indicate a
1.1 cvs 3860: maximum or minimum number of ancestors. If these symbols are missing, the
1.18 cvs 3861: condition is satisfied only if it exists exactly <i>n</i> ancestors. When
1.30 cvs 3862: this number is missing, it is equivalent to > 0.</p>
3863:
3864: <p>If the condition applies to presentation rules associated with an
3865: attribute, in the <tt>ATTRIBUTES</tt> section of the presentation schema, the
3866: condition can be simply an element name. Presentation rules are then executed
3867: only if the attribute is attached to an element of that type. The keyword
3868: <tt>NOT</tt> before the element name indicates that the presentation rules
3869: must be executed only if the element is not of the type indicated.</p>
1.18 cvs 3870: </div>
1.1 cvs 3871:
1.18 cvs 3872: <div class="subsubsection">
1.30 cvs 3873: <h4><a name="sectd42142">Conditions on references</a></h4>
3874:
3875: <p>References may be taken into account in conditions, which can be based on
3876: the fact that the element, or one of its ancestors, is designated by a at
3877: least one reference (<tt>Referred</tt>) or by none (<tt>NOT
3878: Referred</tt>).</p>
3879:
3880: <p>If the element or attribute to which the condition is attached is a
3881: reference, the condition can be based on the fact that it acts as the first
3882: reference to the designated element (<tt>FirstRef</tt>), or as the last
3883: (<tt>LastRef</tt>), or as a reference to an element located in another
3884: document (<tt>ExternalRef</tt>) or in the same document
3885: (<tt>InternalRef</tt>).</p>
1.1 cvs 3886:
1.30 cvs 3887: <p>The condition can also be based on the fact that the element is an <a
1.18 cvs 3888: href="#inclusion">inclusion</a>. This is noted (<tt>CopyRef</tt>).</p>
1.30 cvs 3889:
3890: <p>Like all conditions, conditions on references can be inverted by the
1.18 cvs 3891: <tt>NOT</tt> keyword. These conditions can be associated only with <a
3892: href="#sectc4232">creation rules</a>.</p>
3893: </div>
1.1 cvs 3894:
1.18 cvs 3895: <div class="subsubsection">
1.30 cvs 3896: <h4><a name="sectd42143">Conditions on logical attributes</a></h4>
3897:
3898: <p>The condition can be based on the presence or absence of attributes
3899: associated with the element, no matter what the attributes or their values.
3900: The <tt>AnyAttributes</tt> keyword expresses this condition.</p>
1.1 cvs 3901:
1.30 cvs 3902: <p>If the condition appears in the presentation rules of an attribute, the
1.18 cvs 3903: <tt>FirstAttr</tt> and <tt>LastAttr</tt> keywords can be used to indicate that
1.1 cvs 3904: the rules must only be applied if this attribute is the first attribute for
3905: the element or if it is the last (respectively). These conditions can also be
1.18 cvs 3906: inverted by the <tt>NOT</tt> keyword. These conditions can be associated only
3907: with <a href="#sectc4232">creation rules</a>.</p>
1.30 cvs 3908:
3909: <p>It is also possible to apply certain presentation rules only when the
3910: element being processed or one of its ancestors has a certain attribute,
3911: perhaps with a certain value. This can be done in the <a
1.18 cvs 3912: href="#sectc4210"><tt>ATTRIBUTES</tt> section</a>.</p>
3913: </div>
1.1 cvs 3914:
1.18 cvs 3915: <div class="subsubsection">
1.30 cvs 3916: <h4><a name="sectd42144">Conditions on page breaks</a></h4>
1.1 cvs 3917:
1.30 cvs 3918: <p>The page break base type (and only this type) can use the following
1.18 cvs 3919: conditions: <tt>ComputedPage</tt>, <tt>StartPage</tt>, and <tt>UserPage</tt>.
3920: The <tt>ComputedPage</tt> condition indicates that the presentation rule(s)
1.1 cvs 3921: should apply if the page break was created automatically by Thot; the
1.18 cvs 3922: <tt>StartPage</tt> condition is true if the page break is generated before the
3923: element by the <tt>Page</tt> rule; and the <tt>UserPage</tt> condition applies
3924: if the page break was inserted by the user.</p>
1.30 cvs 3925:
3926: <p>These conditions can be associated only with <a href="#sectc4232">creation
1.18 cvs 3927: rules</a>.</p>
3928: </div>
1.1 cvs 3929:
1.18 cvs 3930: <div class="subsubsection">
1.30 cvs 3931: <h4><a name="sectd42145">Conditions on the element's content</a></h4>
1.1 cvs 3932:
1.30 cvs 3933: <p>The condition can be based on whether or not the element is empty. An
3934: element which has no children or whose leaves are all empty is considered to
3935: be empty itself. This condition is expressed by the <tt>Empty</tt> keyword,
3936: optionally preceded by the <tt>NOT</tt> keyword. This condition can be
3937: associated only with <a href="#sectc4232">creation rules</a>.</p>
1.18 cvs 3938: </div>
1.1 cvs 3939:
1.18 cvs 3940: <div class="subsubsection">
1.30 cvs 3941: <h4><a name="sectd42146">Conditions on counters</a></h4>
1.1 cvs 3942:
1.30 cvs 3943: <p>Presentation rules can apply when the counter's value is one, is even or
3944: odd, is equal, greater than or less than a given value or falls in a range of
1.1 cvs 3945: values. This is particularly useful for creating header and footer boxes.
1.18 cvs 3946: These conditions can be associated only with <a href="#sectc4232">creation
3947: rules</a>.</p>
1.30 cvs 3948:
3949: <p>To compare the value of a counter to a given value, a comparison is given
1.1 cvs 3950: between parentheses. The comparison is composed of the counter name followed
3951: by an equals, greater than, or less than sign and the value to which the
3952: counter will be compared. A test for whether or not a counter's value falls
3953: in a range also appears within parentheses. In this case, the counter name is
1.18 cvs 3954: followed by the <tt>IN</tt> keyword and the range definition within brackets.
3955: The <tt>Even</tt>, <tt>Odd</tt> and <tt>One</tt> are used to test a counter's
3956: value and are followed by the counter name between parentheses.</p>
1.30 cvs 3957:
3958: <p>The list of possible conditions on counters is:</p>
1.18 cvs 3959: <dl>
1.30 cvs 3960: <dt><tt>Even (Counter)</tt></dt>
3961: <dd>the box is created only if the counter has an even value.</dd>
3962: <dt><tt>Odd (Counter)</tt></dt>
3963: <dd>the box is created only if the counter has an odd value.</dd>
3964: <dt><tt>One (Counter)</tt></dt>
3965: <dd>the box is created only the counter's value is 1.</dd>
3966: <dt><tt>NOT One (Counter)</tt></dt>
3967: <dd>the box is created, unless the counter's value is 1.</dd>
3968: <dt><tt>(Counter < Value)</tt></dt>
3969: <dd>the box is created only if the counter's value is less than
3970: Value.</dd>
3971: <dt><tt>(Counter > Value)</tt></dt>
3972: <dd>the box is created only if the counter's value is greater than
3973: Value.</dd>
3974: <dt><tt>(Counter = Value)</tt></dt>
3975: <dd>the box is created only if the counter's value is equal to Value.</dd>
3976: <dt><tt>NOT (Counter = Value)</tt></dt>
3977: <dd>the is created only if the counter's value is different than
3978: Value.</dd>
3979: <dt><tt>(Counter IN [MinValue..MaxValue])</tt></dt>
3980: <dd>the box is created only if the counter's value falls in the range
3981: bounded by MinValue and MaxValue (inclusive).</dd>
3982: <dt><tt>NOT (Counter IN [MinValue..MaxValue])</tt></dt>
3983: <dd>the box is created only if the value of the counter does not fall in
3984: the range bounded by MinValue and MaxValue (inclusive).</dd>
1.18 cvs 3985: </dl>
1.30 cvs 3986:
3987: <p><strong>Note:</strong> the <tt>NOT Even</tt> and <tt>NOT Odd</tt>
3988: conditions are syntactically correct but can be expressed more simply by
3989: <tt>Odd</tt> and <tt>Even</tt>, respectively.</p>
1.18 cvs 3990: </div>
3991: </div>
1.1 cvs 3992:
1.18 cvs 3993: <div class="subsection">
1.30 cvs 3994: <h3><a name="sectc4215">A presentation rule</a></h3>
1.1 cvs 3995:
1.34 cvs 3996: <p>A presentation rule defines either a presentation property or presentation
3997: function. The properties are:</p>
1.18 cvs 3998: <ul>
1.30 cvs 3999: <li>the position of the vertical and horizontal reference axes of the
4000: box,</li>
4001: <li>the position of the box in relation to other boxes,</li>
4002: <li>the height or width of the box, with overflow exceptions,</li>
4003: <li>the margins, padding and borders of the box,</li>
4004: <li>the characteristics of the lines contained in the box: linespacing,
1.35 cvs 4005: indentation of the first line, hyphenation,</li>
1.30 cvs 4006: <li>the conditions for breaking the box across pages,</li>
4007: <li>the characteristics of the characters contained in the box: size, font,
4008: style, underlining,</li>
4009: <li>the depth of the box among overlapping boxes (often called stacking
4010: order),</li>
4011: <li>the characteristics of graphic elements contained in the box: style and
4012: thickness of lines, fill pattern for closed objects,</li>
4013: <li>the colors in text, graphics, pictures, and symbols contained in the box
4014: are displayed or printed,</li>
4015: <li>for presentation boxes only, the contents of the box.</li>
4016: </ul>
4017:
4018: <p>The <a name="presfunct">presentation functions</a> are:</p>
4019: <ul>
4020: <li>the creation of a presentation box</li>
4021: <li>the line-breaking or page-breaking style,</li>
4022: <li>the copying of another box,</li>
4023: <li>the display of the box background and border,</li>
4024: <li>the display of a background picture and its aspect.</li>
4025: </ul>
4026:
1.34 cvs 4027: <p>For each box and each view, every presentation property is defined once and
4028: only once, either explicitly or by the <a href="#sectc427">default rules</a>.
4029: In contrast, presentation functions are not obligatory and can appear many
4030: times for the same element. for example an element can create many
4031: presentation boxes. Another element may not use any presentation
1.18 cvs 4032: functions.</p>
1.30 cvs 4033:
1.34 cvs 4034: <p>Each rule defining a presentation property begins with a keyword followed
4035: by a colon. The keyword indicates the property which is the subject of the
1.18 cvs 4036: rule. After the keyword and the colon, the remainder of the rule varies. All
4037: rules are terminated by a semicolon.</p>
1.34 cvs 4038: <pre> Rule = Property ';' / PresFunc ';' .
4039: Property ='VertRef' ':' PositionHoriz /
1.6 cvs 4040: 'HorizRef' ':' PositionVert /
4041: 'VertPos' ':' VPos /
4042: 'HorizPos' ':' HPos /
4043: 'Height' ':' Dimension /
4044: 'Width' ':' Dimension /
4045: 'VertOverflow' ':' Boolean /
1.1 cvs 4046: 'HorizOverflow' ':' Boolean /
1.26 cvs 4047: 'MarginTop' ':' MarginWidth /
4048: 'MarginRight' ':' MarginWidth /
4049: 'MarginBottom' ':' MarginWidth /
4050: 'MarginLeft' ':' MarginWidth /
4051: 'PaddingTop' ':' PaddingWidth /
4052: 'PaddingRight' ':' PaddingWidth /
4053: 'PaddingBottom' ':' PaddingWidth /
4054: 'PaddingLeft' ':' PaddingWidth /
4055: 'BorderTopWidth' ':' BorderWidth /
4056: 'BorderRightWidth' ':' BorderWidth /
4057: 'BorderBottomWidth' ':' BorderWidth /
4058: 'BorderLeftWidth' ':' BorderWidth /
4059: 'BorderTopColor' ':' BorderColor /
4060: 'BorderRightColor' ':' BorderColor /
4061: 'BorderBottomColor' ':' BorderColor /
4062: 'BorderLeftColor' ':' BorderColor /
4063: 'BorderTopStyle' ':' BorderStyle /
4064: 'BorderRightStyle' ':' BorderStyle /
4065: 'BorderBottomStyle' ':' BorderStyle /
4066: 'BorderLeftStyle' ':' BorderStyle .
1.6 cvs 4067: 'LineSpacing' ':' DistanceInherit /
4068: 'Indent' ':' DistanceInherit /
4069: 'Adjust' ':' AdjustInherit /
4070: 'Hyphenate' ':' BoolInherit /
4071: 'PageBreak' ':' Boolean /
4072: 'LineBreak' ':' Boolean /
4073: 'InLine' ':' Boolean /
4074: 'NoBreak1' ':' AbsDist /
4075: 'NoBreak2' ':' AbsDist /
4076: 'Gather' ':' Boolean /
4077: 'Visibility' ':' NumberInherit /
4078: 'Size' ':' SizeInherit /
4079: 'Font' ':' NameInherit /
4080: 'Style' ':' StyleInherit /
1.23 cvs 4081: 'Weight' ':' WeightInherit /
1.6 cvs 4082: 'Underline' ':' UnderLineInherit /
4083: 'Thickness' ':' ThicknessInherit /
4084: 'Depth' ':' NumberInherit /
4085: 'LineStyle' ':' LineStyleInherit /
4086: 'LineWeight' ':' DistanceInherit /
4087: 'FillPattern' ':' NameInherit /
4088: 'Background' ':' NameInherit /
1.13 cvs 4089: 'Foreground' ':' NameInherit /
1.6 cvs 4090: 'Content' ':' VarConst .
1.1 cvs 4091: PresFunc = Creation '(' BoxID ')' /
4092: 'Line' /
4093: 'NoLine' /
4094: 'Page' '(' BoxID ')' /
1.13 cvs 4095: 'Copy' '(' BoxTypeToCopy ')' /
4096: 'ShowBox' /
1.18 cvs 4097: 'BackgroundPicture' ':' FileName /
4098: 'PictureMode' ':' PictMode /</pre>
4099: </div>
4100:
4101: <div class="subsection">
1.30 cvs 4102: <h3><a name="sectc4216">Box axes</a></h3>
1.18 cvs 4103:
1.30 cvs 4104: <p>The position of the middle axes <tt>VMiddle</tt> and <tt>HMiddle</tt> in
1.1 cvs 4105: relation to their box is always calculated automatically as a function of the
4106: height and width of the box and is not specified by the presentation rules. In
4107: the presentation schema, these middle axes are used only to position their box
4108: with respect to another by specifying the distance between the middle axis and
1.18 cvs 4109: an axis or a side of another box (see the <a href="#sectc4218">relative
4110: position</a>).</p>
1.30 cvs 4111:
4112: <p>The reference axes of a box are also used to position their box in relation
4113: to another, but in contrast to the middle axes, the presentation schema must
4114: make their position explicit, either in relation to a side or the middle axis
4115: of the box itself, or in relation to an axis of an enclosed box.</p>
4116:
4117: <p>Only boxes of base elements have predefined reference axes. For character
1.1 cvs 4118: string boxes, the horizontal reference axis is the baseline of the characters
4119: (the line which passes immediately under the upper-case letters, ignoring the
4120: letter Q) and the vertical reference axis is at the left edge of the first
1.18 cvs 4121: character of the string.</p>
1.30 cvs 4122:
4123: <p>The positions of a box's reference axes are defined by the <tt>VertRef</tt>
1.18 cvs 4124: and <tt>HorizRef</tt> rules which specify the <a href="#distance">distance</a>
1.1 cvs 4125: between the reference axis and an axis or parallel side of the same box or of
1.18 cvs 4126: an enclosed box.</p>
4127: <pre> 'VertRef' ':' PositionHoriz
4128: 'HorizRef' ':' PositionVert</pre>
1.30 cvs 4129:
1.18 cvs 4130: <blockquote class="example">
1.30 cvs 4131: <p><strong>Example:</strong></p>
4132:
4133: <p>If, in the structure schema for mathematical formulas, the fraction
4134: element is defined by</p>
4135: <pre>Fraction = BEGIN
1.1 cvs 4136: Numerator = Expression;
4137: Denominator = Expression;
1.18 cvs 4138: END;</pre>
1.30 cvs 4139:
4140: <p>then the horizontal reference axis of the fraction can be positioned on
4141: top of the denominator by the rule:</p>
4142: <pre>Fraction :
1.1 cvs 4143: BEGIN
4144: HorizRef : Enclosed Denominator . Top;
4145: ...
1.18 cvs 4146: END;</pre>
1.30 cvs 4147:
4148: <p>To put the horizontal reference axis of a column at its middle:</p>
4149: <pre>Column :
1.1 cvs 4150: BEGIN
4151: HorizRef : * . HMiddle;
4152: ...
1.18 cvs 4153: END;</pre>
4154: </blockquote>
4155: </div>
1.1 cvs 4156:
1.18 cvs 4157: <div class="subsection">
1.30 cvs 4158: <h3><a name="sectc4217">Distance units</a></h3>
1.1 cvs 4159:
1.30 cvs 4160: <p>Some distances and dimensions appear in many rules of a presentation
4161: schema, especially in position rules (<tt>VertPos, HorizPos</tt>), in extent
4162: rules for boxes (<tt>Height, Width</tt>), in rules defining lines
4163: (<tt>LineSpacing, Indent</tt>), in rules controlling pagination (<tt>NoBreak1,
4164: NoBreak2</tt>) and in rules specifying the thickness of strokes
4165: (<tt>LineWeight</tt>).</p>
4166:
4167: <p>In all these rules, the distance or extent can be expressed</p>
4168: <ul>
4169: <li>either in relative units, which depend on the size of the characters in
4170: the current font: height of the element's font or height of the letter
4171: 'x',</li>
4172: <li>or in absolute units: centimeter, millimeter, inch, typographer's point,
4173: pica or pixel.</li>
4174: </ul>
4175:
4176: <p>Units can be chosen freely. Thus, it is possible to use relative units in
4177: one rule, centimeters in the next rule, and typographer's points in
4178: another.</p>
4179:
4180: <p>Absolute units are used to set rigid rules for the appearance of documents.
4181: In contrast, relative units allow changes of scale. The editor lets the value
4182: of relative units be changed dynamically. Such changes affect every box using
1.1 cvs 4183: relative units simultaneously and in the same proportion. Changing the value
4184: of the relative units affects the size of the characters and graphical
1.18 cvs 4185: elements, and the size of the boxes and the distances between them.</p>
1.30 cvs 4186:
4187: <p>A <a name="distance">distance</a> or extent is specified by a number, which
1.1 cvs 4188: may be followed by one or more spaces and a units keyword. When there is no
4189: units keyword, the number specifies the number of relative units, where a
4190: relative unit is the height of a character in the current font (an em). When
4191: the number is followed by a units keyword, the keyword indicates the type of
1.18 cvs 4192: absolute units:</p>
4193: <ul>
1.30 cvs 4194: <li><tt>em</tt>: height of the element's font,</li>
4195: <li><tt>ex</tt>: height of the letter 'x',</li>
4196: <li><tt>cm</tt>: centimeter,</li>
4197: <li><tt>mm</tt>: millimeter,</li>
4198: <li><tt>in</tt>: inch (1 in = 2.54 cm),</li>
4199: <li><tt>pt</tt>: point (1 pt = 1/72 in),</li>
4200: <li><tt>pc</tt>: pica (1 pc = 12 pt),</li>
4201: <li><tt>px</tt>: pixel.</li>
1.18 cvs 4202: </ul>
1.30 cvs 4203:
4204: <p>Whatever the chosen unit, relative or absolute, the number is not
4205: necessarily an integer and may be expressed in fixed point notation (using the
4206: American convention of a period to express the decimal point).</p>
4207:
4208: <p>If the distance appears in a presentation rule for a numeric attribute, the
1.1 cvs 4209: number can be replaced by the name of an attribute. In this case, the value
4210: of the attribute is used. Obviously, the attribute name cannot be followed by
4211: a decimal point and a fractional part, but it can be followed a units keyword.
1.18 cvs 4212: However, the choice of units is limited to em, ex, pt and px.</p>
4213: <pre> Distance = [ Sign ] AbsDist .
1.1 cvs 4214: Sign ='+' / '-' .
4215: AbsDist = IntegerOrAttr [ '.' DecimalPart ]
4216: [ Unit ].
4217: IntegerOrAttr = IntegerPart / AttrID .
4218: IntegerPart = NUMBER .
4219: DecimalPart = NUMBER .
4220: Unit ='em' / 'ex' / 'cm' / 'mm' / 'in' / 'pt' /
1.18 cvs 4221: 'pc' / 'px' / '%' .</pre>
1.30 cvs 4222:
1.18 cvs 4223: <blockquote class="example">
1.30 cvs 4224: <p><strong>Example:</strong></p>
4225:
4226: <p>The following rules specify that a box has a height of 10.5 centimeters
4227: and a width of 5.3 ems:</p>
4228: <pre>Height : 10.5 cm;
1.18 cvs 4229: Width : 5.3;</pre>
4230: </blockquote>
4231: </div>
1.1 cvs 4232:
1.18 cvs 4233: <div class="subsection">
1.30 cvs 4234: <h3><a name="sectc4218">Relative positions</a></h3>
1.1 cvs 4235:
1.30 cvs 4236: <p>The positioning of boxes uses the eight axes and sides, the sides generally
1.1 cvs 4237: being used to define the juxtapositioning (vertical or horizontal) of boxes,
4238: the middle axes being used to define centering, and the reference axes being
1.18 cvs 4239: used for alignment.</p>
1.30 cvs 4240:
4241: <p>Two rules allow a box to be placed relative to other boxes. The
1.18 cvs 4242: <tt>VertPos</tt> rule positions the box vertically. The <tt>HorizPos</tt>
4243: rule positions the box horizontally. It is possible that a box's position
4244: could be entirely determined by other boxes positioned relative to it. In this
4245: case, the position is implicit and the word <tt>nil</tt> can be used to
4246: specify that no position rule is needed. Otherwise, an explicit rule must be
4247: given by indicating the axis or side which defines the position of the box,
4248: followed by an equals sign and the distance between between this axis or side
4249: and a parallel axis or side of another box, called the reference box. The box
4250: for which the rule is written will be positioned relative to the reference
4251: box.</p>
4252: <pre> 'VertPos' ':' VPos
1.6 cvs 4253: 'HorizPos' ':' HPos
4254: HPos = 'nil' / VertAxis '=' HorizPosition
4255: [ 'UserSpecified' ].
4256: VPos = 'nil' / HorizAxis '=' VertPosition
4257: [ 'UserSpecified' ].
1.1 cvs 4258: VertAxis = 'Left' / 'VMiddle' / 'VRef' / 'Right' .
1.18 cvs 4259: HorizAxis = 'Top' / 'HMiddle' / 'HRef' / 'Bottom' .</pre>
1.30 cvs 4260:
4261: <p>The reference box is an adjacent box: enclosing, enclosed or adjacent. When
4262: a rule is associated with a reference type attribute (and only in this case),
4263: it can be a box of the element designated by the attribute. The reference box
1.18 cvs 4264: can be either a presentation box previously defined in the <tt>BOXES</tt>
1.1 cvs 4265: section of the schema and created by a creation function, or the box
1.18 cvs 4266: associated with a structured element.</p>
1.30 cvs 4267:
4268: <p>The structural position of the reference box (relative to the box for which
1.18 cvs 4269: the rule is being written) is indicated by a keyword: <tt>Enclosing</tt>,
4270: <tt>Enclosed</tt>, or, for sibling boxes, <tt>Previous</tt> or <tt>Next</tt>.
1.1 cvs 4271: The reference attributes, or presentation boxes created by a reference
1.18 cvs 4272: attribute, the <tt>Referred</tt> keyword may be used to designate the element
4273: which the reference points to. The keyword <tt>Creator</tt> can be used in
1.1 cvs 4274: rules for presentation boxes to designate the box of the element which created
1.18 cvs 4275: the presentation box. Finally, the <tt>Root</tt> keyword can be used to
4276: designate the root of the document.</p>
1.30 cvs 4277:
4278: <p>When the keyword is ambiguous, it is followed by the name of an element
4279: type or presentation box which resolves the ambiguity (the <tt>Creator</tt>
4280: and <tt>Root</tt> keywords are never ambiguous). If this name is not given,
4281: then the first box encountered is used as the reference box. It is also
4282: possible to use just the name of an element type or presentation box without
4283: an initial keyword. In this case, a sibling having that name will be used. If
4284: the name is preceded by the keyword <tt>NOT</tt>, then the reference box will
4285: be the first box whose type is not the named one.</p>
4286:
4287: <p>In place of the box or type name, the keywords <tt>AnyElem</tt>,
1.18 cvs 4288: <tt>AnyBox</tt> and <tt>ElemWithAttr</tt> can be used, representing
1.17 cvs 4289: respectively, any structured element box, any presentation box, and the box
4290: corresponding to any structured element having a particular attribute,
4291: whatever its value; the name of this attribute must follow the keyword
1.18 cvs 4292: <tt>ElemWithAttr</tt>.</p>
1.30 cvs 4293:
4294: <p>A type name may be preceded by a star in order to resolve the ambiguity in
4295: the special case where the structure schema defines an <a
1.18 cvs 4296: href="#sectd3284">inclusion</a> without expansion (or with partial expansion)
4297: of the same type as an element of the scheme. For mark pairs (and only for <a
4298: href="#sectd3285">mark pairs</a>) the type name <em>must</em> be preceded by
4299: the <tt>First</tt> or <tt>Second</tt> keyword, which indicates which of the
4300: two marks of the pair should be used as the reference box.</p>
1.30 cvs 4301:
4302: <p>The star character ('<tt>*</tt>') used alone designates the box to which
4303: the rule applies (in this case, it is obviously useless to specify the type of
4304: the reference box).</p>
4305:
4306: <p>The keywords <tt>Enclosing</tt> and <tt>Enclosed</tt> can be used no matter
1.1 cvs 4307: what constructor defines the type to which the rule applies. When applied to
1.18 cvs 4308: the element which represents the entire document, <tt>Enclosing</tt>
1.1 cvs 4309: designates the window or page in which the document's image is displayed for
4310: the view to which the rule applies. A box or type name without a keyword is
4311: used for aggregate elements and designates another element of the same
4312: aggregate. It can also be used to designate a presentation or page layout
1.18 cvs 4313: box. The keywords <tt>Previous</tt> and <tt>Next</tt> are primarily used to
1.1 cvs 4314: denote list elements, but can also be used to denote elements of an
1.18 cvs 4315: aggregate.</p>
1.30 cvs 4316:
4317: <p>In the position rule, the structural position relative to the reference box
4318: is followed, after a period, by the name of an axis or side. The rule
4319: specifies its node's position as being some distance from this axis or side of
4320: the reference box. If this distance is zero, then the distance does not
4321: appear in the rule. Otherwise, it does appear as a positive or negative
4322: number (the sign is required for negative numbers). The sign takes into
4323: account the orientation of the coordinate axes: for top to bottom for the
4324: vertical axis and from left to right for the horizontal axis. Thus, a
4325: negative distance in a vertical position indicates that the side or axis
4326: specified in the rule is above the side or axis of the reference box.</p>
4327:
4328: <p>The distance can be followed by the <tt>UserSpecified</tt> keyword (even if
1.18 cvs 4329: the distance is nil and does not appear, the <tt>UserSpecified</tt> keyword
1.1 cvs 4330: can be used). It indicates that when the element to which the rule applies is
4331: being created, the editor will ask the user to specify the distance himself,
4332: using the mouse. In this case, the distance specified in the rule is a
4333: default distance which is suggested to the user but can be modified. The
1.18 cvs 4334: <tt>UserSpecified</tt> keyword can be used either in the vertical position
4335: rule, the horizontal position rule, or both.</p>
4336: <pre> VertPosition = Reference '.' HorizAxis [ Distance ] .
1.1 cvs 4337: HorizPosition = Reference '.' VertAxis [ Distance ] .
4338: Reference ='Enclosing' [ BoxTypeNot ] /
4339: 'Enclosed' [ BoxTypeNot ] /
4340: 'Previous' [ BoxTypeNot ] /
4341: 'Next' [ BoxTypeNot ] /
4342: 'Referred' [ BoxTypeNot ] /
4343: 'Creator' /
4344: 'Root' /
4345: '*' /
4346: BoxOrType .
4347: BoxOrType = BoxID /
4348: [ '*' ] [ FirstSec ] ElemID /
1.17 cvs 4349: 'AnyElem' / 'AnyBox' /
4350: 'ElemWithAttr' AttrID .
1.18 cvs 4351: BoxTypeNot = [ 'NOT' ] BoxOrType .</pre>
1.30 cvs 4352:
1.18 cvs 4353: <blockquote class="example">
1.30 cvs 4354: <p><strong>Example:</strong></p>
4355:
4356: <p>If a <a name="expos1">report</a> is defined by the following structure
4357: schema:</p>
4358: <pre>Report = BEGIN
1.6 cvs 4359: Title = Text;
4360: Summary = Text;
4361: Keywords = Text;
4362: ...
1.18 cvs 4363: END;</pre>
1.30 cvs 4364:
4365: <p>then the presentation schema could contain the rules:</p>
4366: <pre>Report : BEGIN
1.6 cvs 4367: VertPos : Top = Enclosing . Top;
4368: HorizPos : Left = Enclosing . Left;
4369: ...
1.18 cvs 4370: END;</pre>
1.30 cvs 4371:
4372: <p>These rules place the <a name="reportexample">report</a> in the upper
4373: left corner of the enclosing box, which is the window in which the document
4374: is being edited.</p>
4375: <pre>Title : BEGIN
1.6 cvs 4376: VertPos : Top = Enclosing . Top + 1;
4377: HorizPos : VMiddle = Enclosing . VMiddle;
4378: ...
1.18 cvs 4379: END;</pre>
1.30 cvs 4380:
4381: <p>The top of the title is one line (a line has the height of the characters
4382: of the title) from the top of the report, which is also the top of the
4383: editing window. The title is centered horizontally in the window (see <a
4384: href="#posdim">figure</a>).</p>
4385: <pre>Summary : BEGIN
1.1 cvs 4386: VertPos : Top = Title . Bottom + 1.5;
4387: HorizPos : Left = Enclosing . Left + 2 cm;
4388: ...
1.18 cvs 4389: END;</pre>
1.30 cvs 4390:
4391: <p>The top of the summary is place a line and a half below the bottom of the
4392: title and is shifted two centimeters from the side of the window.</p>
1.18 cvs 4393: </blockquote>
1.30 cvs 4394:
1.18 cvs 4395: <blockquote class="example">
1.30 cvs 4396: <p><strong>Example:</strong></p>
4397:
4398: <p>Suppose there is a <a name="expos2">Design</a> logical structure which
4399: contains graphical elements:</p>
4400: <pre>Design = LIST OF (ElemGraph = GRAPHICS);</pre>
4401:
4402: <p>The following rules allow the user to freely choose the position of each
4403: element when it is created:</p>
4404: <pre>ElemGraph =
1.1 cvs 4405: BEGIN
4406: VertPos : Top = Enclosing . Top + 1 cm UserSpecified;
4407: HorizPos: Left = Enclosing . Left UserSpecified;
4408: ...
1.18 cvs 4409: END;</pre>
1.30 cvs 4410:
4411: <p>Thus, when a graphical element is created, its default placement is at
4412: the left of the window and 1 cm from the top, but the user can move it
4413: immediately, simply by moving the mouse.</p>
1.18 cvs 4414: </blockquote>
4415: </div>
1.1 cvs 4416:
1.18 cvs 4417: <div class="subsection">
1.30 cvs 4418: <h3><a name="sectc4219">Box extents</a></h3>
1.1 cvs 4419:
1.30 cvs 4420: <p>The extents (height and width) of each box are defined by the two rules
1.18 cvs 4421: <tt>Height</tt> and <tt>Width</tt>. There are three types of extents: fixed,
4422: relative, and elastic.</p>
1.1 cvs 4423:
1.18 cvs 4424: <div class="subsubsection">
1.30 cvs 4425: <h4><a name="sectd42191">Fixed extents</a></h4>
1.1 cvs 4426:
1.30 cvs 4427: <p>A fixed dimension sets the height or width of the box independently of all
1.18 cvs 4428: other boxes. It is expressed in <a href="#sectc4217">distance units</a>. The
4429: extent can be followed by the <tt>UserSpecified</tt> keyword which indicates
1.1 cvs 4430: that when the element to which the rule applies is being created, the editor
4431: will ask the user to specify the extent himself, using the mouse. In this
4432: case, the extent specified in the rule is a default extent which is suggested
1.18 cvs 4433: to the user but can be modified. The <tt>UserSpecified</tt> keyword can be
4434: used either in the <tt>Height</tt> rule, the <tt>Width</tt> rule, or both.</p>
1.30 cvs 4435:
4436: <p>A fixed extent rule can be ended by the <tt>Min</tt> keyword, which
4437: signifies that the indicated value is a minimum, and that, if the contents of
4438: the box require it, a larger extent is possible.</p>
1.18 cvs 4439: <pre> 'Height' ':' Dimension
1.1 cvs 4440: 'Width' ':' Dimension
4441: Dimension = AbsDist [ 'UserSpecified' ] [ 'Min' ] /
1.18 cvs 4442: ...</pre>
1.30 cvs 4443:
1.18 cvs 4444: <blockquote class="example">
1.30 cvs 4445: <p><strong>Example:</strong></p>
4446:
4447: <p>Continuing with the <a href="#expos2">previous example</a>, it is
4448: possible to allow the user to choose the size of each graphical element as
4449: it is created:</p>
4450: <pre>ElemGraph : BEGIN
1.6 cvs 4451: Width : 2 cm UserSpecified;
1.1 cvs 4452: Height : 1 cm UserSpecified;
4453: ...
1.18 cvs 4454: END;</pre>
1.30 cvs 4455:
4456: <p>Thus, when a graphical element is create, it is drawn by default with a
4457: width of 2 cm and a height of 1 cm, but the user is free to resize it
4458: immediately with the mouse.</p>
4459: <pre>Summary : BEGIN
1.1 cvs 4460: Height : 5 cm Min;
4461: ...
4462: END;
4463: Keywords : BEGIN
4464: VertPos : Top = Summary . Bottom;
4465: ...
1.18 cvs 4466: END;</pre>
4467: </blockquote>
4468: </div>
1.1 cvs 4469:
1.18 cvs 4470: <div class="subsubsection">
1.30 cvs 4471: <h4><a name="sectd42192">Relative extents</a></h4>
4472:
4473: <p>A relative extent determines the extent as a function of the extent of
4474: another box, just as a relative position places a box in relation to another.
4475: The reference box in an extent rule is designated using the same syntax as is
4476: used in a relative position rule. It is followed by a period and a
4477: <tt>Height</tt> or <tt>Width</tt> keyword, depending on the extent being
4478: referred to. Next comes the relation between the extent being defined and the
4479: extent of the reference box. This relation can be either a percentage or a
4480: difference.</p>
1.1 cvs 4481:
1.30 cvs 4482: <p>A percentage is indicated by a star (the multiplication symbol) followed by
1.1 cvs 4483: the numeric percentage value (which may be greater than or less than 100) and
4484: the percent (`%') character. A difference is simply indicated by a signed
1.18 cvs 4485: difference.</p>
1.30 cvs 4486:
4487: <p>If the rule appears in the presentation rules of a numeric attribute, the
1.1 cvs 4488: percentage value can be replaced by the name of the attribute. This attribute
1.18 cvs 4489: is then used as a percentage. The attribute can also be used as part of a <a
4490: href="#distance">difference</a>.</p>
1.30 cvs 4491:
4492: <p>Just as with a fixed extent, a relative extent rule can end with the
1.18 cvs 4493: <tt>Min</tt> keyword, which signifies that the extent is a minimum and that,
4494: if the contents of the box require it, a larger extent is possible.</p>
1.30 cvs 4495:
4496: <p>A special case of relative extent rules is:</p>
1.18 cvs 4497: <pre>Height : Enclosed . Height;</pre>
1.30 cvs 4498:
4499: <p>or</p>
1.18 cvs 4500: <pre>Width : Enclosed . Width;</pre>
1.30 cvs 4501:
4502: <p>which specifies that the box has a height (or width) such that it encloses
4503: all the boxes which it contains, excluding boxes having a rule
4504: <tt>VertOverflow: Yes;</tt> or <tt>HorizOverflow: Yes;</tt>.</p>
4505:
4506: <p><strong>Note:</strong> character strings (type <tt>TEXT_UNIT</tt>)
4507: generally must use the sum of the widths of the characters which compose them
4508: as their width, which is expressed by the rule:</p>
1.18 cvs 4509: <pre>TEXT_UNIT :
4510: Width : Enclosed . Width;</pre>
1.30 cvs 4511:
4512: <p>If this rule is not the default <tt>Width</tt> rule, it must be given
1.18 cvs 4513: explicitly in the <tt>RULES</tt> section which defines the presentation rules
4514: of the logical elements.</p>
4515: <pre> 'Height' ':' Extent
1.1 cvs 4516: 'Width' ':' Extent
4517: Extent = Reference '.' HeightWidth [ Relation ]
4518: [ 'Min' ] / ...
4519: HeightWidth ='Height' / 'Width' .
4520: Relation ='*' ExtentAttr '%' / Distance .
4521: ExtentAttr = ExtentVal / AttrID .
1.18 cvs 4522: ExtentVal = NUMBER .</pre>
1.30 cvs 4523:
1.18 cvs 4524: <blockquote class="example">
1.30 cvs 4525: <p><strong>Example:</strong></p>
4526:
4527: <p>Completing the <a href="#expos1">above example</a>, it is possible to
4528: specify that the report takes its width from the editing window and its
4529: height from the size of its contents (this can obviously be greater than
4530: that of the window):</p>
4531: <pre>Report : BEGIN
1.1 cvs 4532: Width : Enclosing . Width;
4533: Height : Enclosed . Height;
4534: ...
1.18 cvs 4535: END;</pre>
1.30 cvs 4536:
4537: <p>Then, the following rules make the title occupy 60% of the width of the
4538: report (which is that of the window) and is broken into centered lines of
4539: this width (see the <a href="#sectc4222"><tt>Line</tt> rule</a>).</p>
4540: <pre>Title : BEGIN
1.1 cvs 4541: Width : Enclosing . Width * 60%;
4542: Height : Enclosed . Height;
4543: Line;
4544: Adjust : VMiddle;
4545: ...
1.18 cvs 4546: END;</pre>
1.30 cvs 4547:
4548: <p>The summary occupy the entire width of the window, with the exception of
4549: a 2 cm margin reserved by the horizontal position rule:</p>
4550: <pre>Summary : BEGIN
1.1 cvs 4551: Width : Enclosing . Width - 2 cm;
4552: Height : Enclosed . Height;
4553: ...
1.18 cvs 4554: END;</pre>
4555:
1.30 cvs 4556: <p>This set of rules, plus the <a href="#reportexample">position rules given
4557: above</a>, produce the layout of boxes shown in the following<a
4558: href="#posdim">figure</a>.</p>
4559:
4560: <div class="figure">
4561: <hr>
4562: <pre>-------------------------------------------------------------
1.1 cvs 4563: | Window and Report ^ |
4564: | | 1 line |
4565: | v |
4566: | ------------------------------------- |
4567: | | | |
4568: : 20% : Title : 20% :
1.30 cvs 4569: :<--------->: :<--------->:
1.1 cvs 4570: : : 60% : :
1.30 cvs 4571: : :<--------------------------------->: :
1.1 cvs 4572: | | | |
4573: | ------------------------------------- |
4574: | ^ |
4575: | | 1.5 line |
4576: | | |
4577: | v |
4578: | ---------------------------------------------------|
4579: | 2 cm | |
1.30 cvs 4580: |<------>| Summary |
1.18 cvs 4581: : : :</pre>
1.19 cvs 4582:
1.30 cvs 4583: <p align="center"><em><a name="posdim">Box position and
4584: extent</a><em></em></em></p>
4585: <hr>
4586: </div>
1.18 cvs 4587: </blockquote>
4588: </div>
1.1 cvs 4589:
1.18 cvs 4590: <div class="subsubsection">
1.30 cvs 4591: <h4><a name="sectd42193">Elastic extents</a></h4>
1.1 cvs 4592:
1.30 cvs 4593: <p>The last type of extent is the elastic extent. Either one or both extents
4594: can be elastic. A box has an elastic extent when two opposite sides are
4595: linked by distance constraints to two sides or axes of other boxes.</p>
4596:
4597: <p>One of the sides of the elastic box is linked by a position rule
1.18 cvs 4598: (<tt>VertPos</tt> or <tt>HorizPos</tt>) to a neighboring box. The other side
4599: is link to another box by a <tt>Height</tt> or <tt>Width</tt> rule, which
1.1 cvs 4600: takes the same form as the position rule. For the elastic box itself, the
4601: notions of sides (left or right, top or bottom) are fuzzy, since the movement
4602: of either one of the two reference boxes can, for example, make the left side
4603: of the elastic box move to the right of its right side. This is not
4604: important. The only requirement is that the two sides of the elastic box used
1.18 cvs 4605: in the position and extent rule are opposite sides of the box.</p>
4606: <pre> 'Height' ':' Extent
1.6 cvs 4607: 'Width' ':' Extent
1.18 cvs 4608: Extent = HPos / VPos / ...</pre>
1.30 cvs 4609:
1.18 cvs 4610: <blockquote class="example">
1.30 cvs 4611: <p><strong>Example:</strong></p>
4612:
4613: <p>Suppose we want to draw an elastic arrow or line between the middle of
4614: the bottom side of box A and the upper left corner of box B. To do this, we
4615: would define a graphics box whose upper left corner coincides with the
4616: middle of the bottom side of A (a position rule) and whose lower right
4617: corner coincides with with the upper left corner of B (dimension rules):</p>
4618: <pre>LinkedBox :
1.1 cvs 4619: BEGIN
1.6 cvs 4620: VertPos : Top = A .Bottom;
1.1 cvs 4621: HorizPos : Left = A . VMiddle;
1.6 cvs 4622: Height : Bottom = B . Top;
4623: Width : Right = B . Left;
1.18 cvs 4624: END;</pre>
4625: </blockquote>
1.30 cvs 4626:
1.18 cvs 4627: <blockquote class="example">
1.30 cvs 4628: <p><strong>Example:</strong></p>
4629:
4630: <p>The element SectionTitle creates a presentation box called SectionNum
4631: which contains the number of the section. Suppose we want to align the
4632: SectionNum and SectionTitle horizontally, have the SectionNum take its width
4633: from its contents (the section number), have the SectionTitle box begin 0.5
4634: cm to the right of the SectionNum box and end at the right edge of its
4635: enclosing box. This would make the SectionTitle box elastic, since its width
4636: is defined by the position of its left and right sides. The following rules
4637: produce this effect:</p>
4638: <pre>SectionNum :
1.1 cvs 4639: BEGIN
4640: HorizPos : Left = Enclosing . Left;
4641: Width : Enclosed . Width;
4642: ...
4643: END;
4644:
4645: SectionTitle :
4646: BEGIN
4647: HorizPos : Left = SectionNum . Right + 0.5 cm;
4648: Width : Right = Enclosing . Right;
4649: ...
1.18 cvs 4650: END;</pre>
4651: </blockquote>
4652: </div>
4653: </div>
1.1 cvs 4654:
1.18 cvs 4655: <div class="subsection">
1.30 cvs 4656: <h3><a name="sectc4220">Overflow</a></h3>
1.1 cvs 4657:
1.30 cvs 4658: <p>A boxes corresponding to a structural element normally contain all boxes
1.1 cvs 4659: corresponding to the elements of its subtree. However, in some cases, it
4660: could be necessary to allow a box to jut out from its parent box. Two
4661: presentation rules indicate that such an overflow is allowed, one for
1.18 cvs 4662: horizontal overflow, one for vertical overflow.</p>
1.30 cvs 4663:
4664: <p>Each of these rules is expressed by a keyword followed by a colon and the
1.18 cvs 4665: keyword <tt>Yes</tt> or <tt>No</tt>.</p>
4666: <pre> 'VertOverflow' ':' Boolean /
1.1 cvs 4667: 'HorizOverflow' ':' Boolean .
1.18 cvs 4668: Boolean = 'Yes' / 'No' .</pre>
4669: </div>
1.1 cvs 4670:
1.30 cvs 4671: <p>@@@@@ ******</p>
4672:
1.26 cvs 4673: <p>Explain Margin, Padding and Border. Refer to CSS2.</p>
4674: <pre> 'MarginTop' ':' MarginWidth /
4675: 'MarginRight' ':' MarginWidth /
4676: 'MarginBottom' ':' MarginWidth /
4677: 'MarginLeft' ':' MarginWidth /
4678: 'PaddingTop' ':' PaddingWidth /
4679: 'PaddingRight' ':' PaddingWidth /
4680: 'PaddingBottom' ':' PaddingWidth /
4681: 'PaddingLeft' ':' PaddingWidth /
4682: 'BorderTopWidth' ':' BorderWidth /
4683: 'BorderRightWidth' ':' BorderWidth /
4684: 'BorderBottomWidth' ':' BorderWidth /
4685: 'BorderLeftWidth' ':' BorderWidth /
4686: 'BorderTopColor' ':' BorderColor /
4687: 'BorderRightColor' ':' BorderColor /
4688: 'BorderBottomColor' ':' BorderColor /
4689: 'BorderLeftColor' ':' BorderColor /
4690: 'BorderTopStyle' ':' BorderStyle /
4691: 'BorderRightStyle' ':' BorderStyle /
4692: 'BorderBottomStyle' ':' BorderStyle /
4693: 'BorderLeftStyle' ':' BorderStyle .
4694:
4695: MarginWidth = InheritParent / 'Auto' / Distance .
4696: PaddingWidth = InheritParent / Distance .
4697: BorderWidth = InheritParent / 'Thin' / 'Medium' / 'Thick' / Distance .
4698: BorderColor = InheritParent / 'Transparent' / 'Foreground' /
4699: ColorName .
4700: BorderStyle = InheritParent /
4701: 'None' / 'Hidden' / 'Dotted' / 'Dashed' / 'Solid' /
4702: 'Double' / 'Groove' / 'Ridge' / 'Inset' / 'Outset' .
1.27 cvs 4703: InheritParent = 'Enclosing' '=' / 'Creator' '=' .
1.26 cvs 4704: ColorName = NAME .</pre>
1.30 cvs 4705:
4706: <p>@@@@@ ******</p>
1.26 cvs 4707:
1.18 cvs 4708: <div class="subsection">
1.30 cvs 4709: <h3><a name="sectc4221">Inheritance</a></h3>
1.1 cvs 4710:
1.34 cvs 4711: <p>A presentation property can be defined by reference to the same property of
4712: another box in the tree of boxes. These structural links are expressed by
1.1 cvs 4713: kinship. The reference box can be that of the element immediately above in
1.18 cvs 4714: the structure (<tt>Enclosing</tt>), two levels above (<tt>GrandFather</tt>),
4715: immediately below (<tt>Enclosed</tt>) or immediately before
4716: (<tt>Previous</tt>). In the case of a presentation box, and only in that
1.1 cvs 4717: case, the reference box may be the element which created the presentation box
1.18 cvs 4718: (<tt>Creator</tt>).</p>
1.30 cvs 4719:
4720: <p>Kinship is expressed in terms of the logical structure of the document and
4721: not in terms of the tree of boxes. The presentation box cannot transmit any
1.34 cvs 4722: of their properties by inheritance; only structured element boxes can do so.
1.30 cvs 4723: As an example, consider an element B which follows an element A in the logical
1.1 cvs 4724: structure. The element B creates a presentation box P in front of itself,
1.18 cvs 4725: using the <tt>CreateBefore</tt> rule (see the <a href="#sectc4232">creation
4726: rules</a>). If element B's box inherits its character style using the
4727: <tt>Previous</tt> kinship operation, it gets its character style from A's box,
1.1 cvs 4728: not from P's box. Inheritance works differently for positions and extents,
1.18 cvs 4729: which can refer to presentation boxes.</p>
1.30 cvs 4730:
1.34 cvs 4731: <p>The inherited property value can be the same as that of the reference box.
4732: This is indicated by an equals sign. However, for numeric properties, a
1.1 cvs 4733: different value can be obtained by adding or subtracting a number from the
1.34 cvs 4734: reference box's property value. Addition is indicated by a plus sign before
1.1 cvs 4735: the number, while subtraction is specified with a minus sign. The value of a
1.34 cvs 4736: property can also be given a maximum (if the sign is a plus) or minimum (if
1.18 cvs 4737: the sign is a minus).</p>
1.30 cvs 4738:
4739: <p>If the rule is being applied to a numeric attribute, the number to add or
1.1 cvs 4740: subtract can be replaced by the attribute name. The value of a maximum or
4741: minimum may also be replaced by an attribute name. In these cases, the value
1.18 cvs 4742: of the attribute is used.</p>
4743: <pre> Inheritance = Kinship InheritedValue .
1.6 cvs 4744: Kinship ='Enclosing' / 'GrandFather' / 'Enclosed' /
4745: 'Previous' / 'Creator' .
1.1 cvs 4746: InheritedValue ='+' PosIntAttr [ 'Max' maximumA ] /
1.6 cvs 4747: '-' NegIntAttr [ 'Min' minimumA ] /
4748: '=' .
4749: PosIntAttr = PosInt / AttrID .
4750: PosInt = NUMBER .
4751: NegIntAttr = NegInt / AttrID .
4752: NegInt = NUMBER .
4753: maximumA = maximum / AttrID .
4754: maximum = NUMBER .
4755: minimumA = minimum / AttrID .
1.18 cvs 4756: minimum = NUMBER .</pre>
1.30 cvs 4757:
1.36 ! cvs 4758: <p>The properties which can be obtained by inheritance are hyphenation,
! 4759: interline spacing, character font (font family), font style, font size,
! 4760: visibility, indentation, underlining, alignment of text, stacking order of
! 4761: objects, the style and thickness of lines, fill pattern and the colors of
1.18 cvs 4762: lines and characters.</p>
4763: </div>
1.1 cvs 4764:
1.18 cvs 4765: <div class="subsection">
1.30 cvs 4766: <h3><a name="sectc4222">Line breaking</a></h3>
1.1 cvs 4767:
1.30 cvs 4768: <p>The <tt>Line</tt> rule specifies that the contents of the box should be
4769: broken into lines: the boxes included in the box to which this rule is
4770: attached are displayed one after the other, from left to right, with their
4771: horizontal reference axes aligned so that they form a series of lines. The
4772: length of these lines is equal to the width of the box to which the
4773: <tt>Line</tt> rule is attached.</p>
4774:
4775: <p>When an included box overflows the current line, it is either carried
4776: forward to the next line, cur, or left the way it is. The <a
1.18 cvs 4777: href="#sectc4223"><tt>LineBreak</tt> rule</a> is used to allow or prevent the
1.1 cvs 4778: breaking of included boxes. If the included box is not breakable but is
4779: longer than the space remaining on the line, it is left as is. When a
4780: character string box is breakable, the line is broken between words or, if
1.18 cvs 4781: necessary, by <a href="#sectd42225">hyphenating a word</a>. When a compound
4782: box is breakable, the box is transparent in regard to line breaking. The boxes
4783: included in the compound box are treated just like included boxes which have
4784: the <tt>LineBreak</tt> rule. Thus, it is possible to traverse a complete
4785: subtree of boxes to line break the text leaves of a complex structure.</p>
1.30 cvs 4786:
4787: <p>The relative position rules of the included boxes are ignored, since the
4788: boxes will be placed according to the line breaking rules.</p>
4789:
4790: <p>The <tt>Line</tt> rule does not have a parameter. The characteristics of
4791: the lines that will be constructed are determined by the <tt>LineSpacing</tt>,
1.36 ! cvs 4792: <tt>Indent</tt>, <tt>Adjust</tt>, and <tt>Hyphenate</tt> rules. Moreover, the
! 4793: <a href="#insectd42226"><tt>Inline</tt> rule</a> permits the exclusion of
! 4794: certain elements from the line breaking process.</p>
1.30 cvs 4795:
4796: <p>When the <tt>Line</tt> rule appears in the rules sequence of a non-primary
1.18 cvs 4797: view, it applies only to that view, but when the <tt>Line</tt> rule appears in
1.1 cvs 4798: the rules sequence of the primary view, it also applies to the other views by
1.18 cvs 4799: default, except for those views which explicitly invoke the <tt>NoLine</tt>
4800: rule. Thus, the <tt>NoLine</tt> rule can be used in a non-primary view to
4801: override the primary view's <tt>Line</tt> rule. The <tt>NoLine</tt> rule must
4802: not be used with the primary view because the absence of the <tt>Line</tt>
4803: rule has the same effect. Like the <tt>Line</tt> rule, the <tt>NoLine</tt>
4804: rule does not take any parameters.</p>
4805: <pre> 'Line'
4806: 'NoLine'</pre>
4807:
4808: <div class="subsubsection">
1.30 cvs 4809: <h4><a name="sectd42221">Line spacing</a></h4>
1.18 cvs 4810:
1.30 cvs 4811: <p>The <tt>LineSpacing</tt> rule defines the line spacing to be used in the
4812: line breaking process. The line spacing is the distance between the baselines
1.1 cvs 4813: (horizontal reference axis) of the successive lines produced by the
1.18 cvs 4814: <tt>Line</tt> rule. The value of the line spacing can be specified as a
4815: constant or by inheritance. It is expressed in any of the available <a
4816: href="#sectc4217">distance units</a>.</p>
1.30 cvs 4817:
4818: <p>Inheritance allows the value to be obtained from a relative in the
4819: structure tree, either without change (an equals sign appears after the
4820: inheritance keyword), with a positive difference (a plus sign), or a negative
4821: difference (a minus sign). When the rule uses a difference, the value of the
4822: difference follows the sign and is expressed as a <a
4823: href="#sectc4217">distance</a>.</p>
1.18 cvs 4824: <pre> 'LineSpacing' ':' DistOrInherit
1.6 cvs 4825: DistOrInherit = Kinship InheritedDist / Distance .
1.18 cvs 4826: InheritedDist = '=' / '+' AbsDist / '-' AbsDist .</pre>
1.30 cvs 4827:
4828: <p>When the line spacing value (or its difference from another element) is
1.1 cvs 4829: expressed in relative units, it changes with the size of the characters. Thus,
4830: when a larger font is chosen for a part of the document, the line spacing of
4831: that part expands proportionally. In contrast, when the line spacing value is
4832: expressed in absolute units (centimeters, inches, typographer's points), it is
4833: independent of the characters, which permits the maintenance of a consistent
4834: line spacing, whatever the character font. Either approach can be taken,
1.18 cvs 4835: depending on the desired effect.</p>
4836: </div>
1.1 cvs 4837:
1.18 cvs 4838: <div class="subsubsection">
1.30 cvs 4839: <h4><a name="sectd42222">First line indentation</a></h4>
1.1 cvs 4840:
1.30 cvs 4841: <p>The <tt>Indent</tt> rule is used to specify the indentation of the first
4842: line of the elements broken into lines by the <tt>Line</tt> function. The
1.1 cvs 4843: indentation determines how far the first line of the element is shifted with
4844: respect to the other lines of the same element. It can be specified as a
4845: constant or by inheritance. The constant value is a positive integer (shifted
4846: to the right; the sign is optional), a negative integer (shifted to the left)
1.18 cvs 4847: or zero (no shift). All available <a href="#sectc4217">units</a> can be
4848: used.</p>
1.30 cvs 4849:
4850: <p>Indentation can be defined for any box, regardless of whether the box is
4851: line broken, and transmitted by inheritance to elements that are line broken.
4852: The size of the indentation is specified in the same manner as the <a
1.18 cvs 4853: href="#sectd42221">line spacing</a>.</p>
4854: <pre> 'Indent' ':' DistOrInherit</pre>
4855: </div>
1.1 cvs 4856:
1.18 cvs 4857: <div class="subsubsection">
1.30 cvs 4858: <h4><a name="sectd42223">Alignment</a></h4>
1.1 cvs 4859:
1.30 cvs 4860: <p>The alignment style of the lines constructed during line breaking is
4861: defined by the <tt>Adjust</tt> rule. The alignment value can be a constant or
1.18 cvs 4862: inherited. A constant value is specified by a keyword:</p>
4863: <ul>
1.30 cvs 4864: <li><tt>Left</tt>: at the left edge,</li>
4865: <li><tt>Right</tt>: at the right edge,</li>
4866: <li><tt>VMiddle</tt>: centered</li>
1.35 cvs 4867: <li><tt>Justify</tt>: justified</li>
1.30 cvs 4868: <li><tt>LeftWithDots</tt>: at the left edge with a dotted line filling out
4869: the last line up to the right edge of the line breaking box.</li>
1.18 cvs 4870: </ul>
1.30 cvs 4871:
4872: <p>An inherited value can only be the same as that of the reference box and is
1.18 cvs 4873: specified by a kinship keyword followed by an equals sign.</p>
4874: <pre> 'Adjust' ':' AlignOrInherit
1.1 cvs 4875: AlignOrInherit = Kinship '=' / Alignment .
1.35 cvs 4876: Alignment = 'Left' / 'Right' / 'VMiddle' / 'Justify' /
1.18 cvs 4877: 'LeftWithDots' .</pre>
4878: </div>
1.1 cvs 4879:
1.18 cvs 4880: <div class="subsubsection">
1.30 cvs 4881: <h4><a name="sectd42225">Hyphenation</a></h4>
1.18 cvs 4882:
1.30 cvs 4883: <p>The <tt>Hyphenate</tt> rule indicates whether or not words should be broken
4884: by hyphenation at the end of lines. It affects the lines produced by the
1.18 cvs 4885: <tt>Line</tt> rule and contained in the box carrying the <tt>Hyphenate</tt>
4886: rule.</p>
1.30 cvs 4887:
1.34 cvs 4888: <p>The hyphenation property takes a boolean value, which can be either
1.30 cvs 4889: constant or inherited. A constant boolean value is expressed by either the
1.18 cvs 4890: <tt>Yes</tt> or the <tt>No</tt> keyword. An inherited value can only be the
1.1 cvs 4891: same as that of the reference box and is specified by a kinship keyword
1.18 cvs 4892: followed by an equals sign.</p>
4893: <pre> 'Hyphenate' ':' BoolInherit
1.1 cvs 4894: BoolInherit = Boolean / Kinship '=' .
1.18 cvs 4895: Boolean = 'Yes' / 'No' .</pre>
4896: </div>
4897:
4898: <div class="subsubsection">
1.30 cvs 4899: <h4><a name="sectd42226">Avoiding line breaking</a></h4>
1.18 cvs 4900:
1.30 cvs 4901: <p>The <tt>InLine</tt> rule is used to specify that a box that would otherwise
1.18 cvs 4902: participate in line breaking asked for by the <tt>Line</tt> rule of an
1.1 cvs 4903: enclosing box, instead avoids the line breaking process and positions itself
1.18 cvs 4904: according to the <tt>HorizPos</tt> and <tt>VertPos</tt> rules that apply to
4905: it. When the <tt>InLine</tt> rule applies to a box which would not be line
4906: broken, it has no effect.</p>
1.30 cvs 4907:
4908: <p>The rule is expressed by the <tt>InLine</tt> keyword followed by a colon
4909: and the keyword <tt>Yes</tt>, if the box should participate in line breaking,
4910: or the keyword <tt>No</tt>, if it should not. This is the only form possible:
1.1 cvs 4911: this rule cannot be inherited. Moreover, it can only appear in the rules of
4912: the primary view and applies to all views defined in the presentation
1.18 cvs 4913: schema.</p>
4914: <pre> 'InLine' ':' Boolean .
4915: Boolean = 'Yes' / 'No' .</pre>
1.30 cvs 4916:
1.18 cvs 4917: <blockquote class="example">
1.30 cvs 4918: <p><strong>Example:</strong></p>
4919:
4920: <p>Suppose the structure schema defines a logical attribute called
4921: <tt>New</tt> which is used to identify the passages in a document which were
4922: recently modified. It would be nice to have the presentation schema make a
4923: bar appear in the left margin next to each passage having the <tt>New</tt>
4924: attribute. A new passage can be an entire element, such as a paragraph or
4925: section, or it can be some words in the middle of a paragraph. To produce
4926: the desired effect, the <tt>New</tt> attribute is given a creation rule
4927: which generates a <tt>VerticalBar</tt> presentation box.</p>
4928:
4929: <p>When the <tt>New</tt> attribute is attached to a character string which
4930: is inside a line broken element (inside a paragraph, for example), the bar
4931: is one of the elements which participates in line breaking and it is placed
4932: normally in the current line, at the end of the character string which has
4933: the attribute. To avoid this, the <tt>InLine</tt> rule is used in the
4934: following way:</p>
4935: <pre>BOXES
1.1 cvs 4936: VerticalBar:
4937: BEGIN
4938: Content: Graphics 'l';
4939: HorizPos: Left = Root . Left;
4940: VertPos: Top = Creator . Top;
4941: Height: Bottom = Creator . Bottom;
4942: Width: 1 pt;
4943: InLine: No;
4944: ...
4945: END;
4946: ...
4947: ATTRIBUTES
4948: Nouveau:
4949: BEGIN
4950: CreateAfter(VerticalBar);
1.18 cvs 4951: END;</pre>
4952: </blockquote>
4953: </div>
4954: </div>
1.1 cvs 4955:
1.18 cvs 4956: <div class="subsection">
1.30 cvs 4957: <h3><a name="sectc4223">Page breaking and line breaking conditions</a></h3>
1.1 cvs 4958:
1.30 cvs 4959: <p>Pages are constructed by the editor in accordance with the model specified
4960: by a <a href="#sectc4233"><tt>Page</tt> rule</a>. The page model describes
4961: only the composition of the pages but does not give any rules for breaking
1.18 cvs 4962: different element types across pages. Now, it is possible that certain
4963: elements must not be cut by page breaks, while others can be cut anywhere. The
4964: <tt>PageBreak</tt>, <tt>NoBreak1</tt>, and <tt>NoBreak2</tt> rules are used to
4965: specify the conditions under which each element type can be cut.</p>
1.30 cvs 4966:
4967: <p>The <tt>PageBreak</tt> rule is used to indicate whether or not the box can
4968: be cut during the construction of pages. If cutting is authorized, the box
4969: can be cut, with one part appearing at the bottom of a page and the other part
1.1 cvs 4970: appearing at the top of the next page. The rule is formed by the
1.18 cvs 4971: <tt>PageBreak</tt> keyword followed by a colon and a constant boolean value
4972: (<tt>Yes</tt> or <tt>No</tt>). This is the only form possible: this rule
1.1 cvs 4973: cannot be inherited. Moreover, it can only appear in the rules of the primary
1.18 cvs 4974: view and applies to all views defined in the presentation schema.</p>
1.30 cvs 4975:
4976: <p>Whether objects can be cut by line breaks can be controlled in a similar
4977: way using the <tt>LineBreak</tt> rule. This rule allows the specification of
1.1 cvs 4978: whether or not the box can be cut during the construction of lines. If
4979: cutting is authorized, the box can be cut, with one part appearing at the end
4980: of a line and the other part appearing at the beginning of the next line. The
1.18 cvs 4981: rule is formed by the <tt>LineBreak</tt> keyword followed by a colon and a
4982: constant boolean value (<tt>Yes</tt> or <tt>No</tt>). This is the only form
1.1 cvs 4983: possible: this rule cannot be inherited. Moreover, it can only appear in the
4984: rules of the primary view and applies to all views defined in the presentation
1.18 cvs 4985: schema.</p>
4986: <pre> 'PageBreak' ':' Boolean .
1.1 cvs 4987: 'LineBreak' ':' Boolean .
1.18 cvs 4988: Boolean = 'Yes' / 'No' .</pre>
1.30 cvs 4989:
4990: <p>When a box can be cut by a page break, it is possible that a page break
4991: will fall an inappropriate spot, creating, for example, a widow or orphan, or
1.1 cvs 4992: separating the title of a section from the first paragraph of the section. The
1.18 cvs 4993: <tt>NoBreak1</tt> and <tt>NoBreak2</tt> rules are used to avoid this. They
4994: specify that the box of the element to which they apply cannot be cut within a
4995: certain zone at the top (<tt>NoBreak1</tt> rule) or at the bottom
4996: (<tt>NoBreak2</tt> rule). These two rules specify the height of the zones in
4997: which page breaks are prohibited.</p>
1.30 cvs 4998:
4999: <p>The <tt>NoBreak1</tt> and <tt>NoBreak2</tt> rules give the height of the
5000: zone in which page breaking is prohibited. The height is given as a constant
5001: value using any of the <a href="#sectc4217">available units</a>, absolute or
1.18 cvs 5002: relative. The value may not be inherited.</p>
5003: <pre> 'NoBreak1' ':' AbsDist .
5004: 'NoBreak2' ':' AbsDist .</pre>
1.30 cvs 5005:
1.18 cvs 5006: <blockquote class="example">
1.30 cvs 5007: <p><strong>Example:</strong></p>
5008:
5009: <p>The following rules prevent widows and orphans in a paragraph:</p>
5010: <pre>Paragraph :
1.1 cvs 5011: BEGIN
5012: NoBreak1 : 2;
5013: NoBreak2 : 2;
1.18 cvs 5014: END;</pre>
1.30 cvs 5015:
5016: <p>This rule prevents a section title from becoming separated from the first
5017: paragraph of the section by prohibiting page breaks at the beginning of the
5018: section rule:</p>
5019: <pre>Section :
1.18 cvs 5020: NoBreak1 : 1.5 cm;</pre>
1.30 cvs 5021:
5022: <p>Finally, this rule prevents a figure from being page broken in any
5023: way:</p>
5024: <pre>Figure :
1.18 cvs 5025: PageBreak : No;</pre>
5026: </blockquote>
1.30 cvs 5027:
5028: <p>The Thot editor constructs the document images displayed on the screen
1.1 cvs 5029: dynamically. As the user moves in the document or makes the document scroll
5030: in a window, the editor constructs the image to be displayed in little bits,
5031: filling the gaps which are produced in the course of these operations. It
5032: stops filling in the image when an element reaches the edge of the window in
5033: which the gap appears. If the appearance of the document is complex, it is
5034: possible that the image in incomplete, even though the edge of the window was
5035: reached. For example, an element might need to be presented to the side of
5036: the last element displayed, but its image was not constructed. The user will
5037: not know whether the element is really absent or if its image has simply not
1.18 cvs 5038: been constructed.</p>
1.30 cvs 5039:
5040: <p>The <tt>Gather</tt> rule is used to remedy this problem. When the rule
1.18 cvs 5041: <tt>Gather : Yes;</tt> is associated with an element type, the image of such
5042: elements is constructed as a block by the editor: it is never split up.</p>
1.30 cvs 5043:
5044: <p>The <tt>Gather</tt> rule may not appear in the <a href="#sectc427">default
1.18 cvs 5045: rules</a>. Elements which do not have the <tt>Gather</tt> rule are considered
5046: susceptible to being split up during display. Thus, it is not necessary to
5047: use the <tt>Gather : No;</tt> form. This rule must be used prudently and only
5048: for those elements which truly need it. If used incorrectly, it can
5049: pointlessly increase the size of the image constructed by the editor and lead
5050: to excessive memory consumption by the editor.</p>
1.30 cvs 5051:
5052: <p>Like the <tt>PageBreak</tt> and <tt>LineBreak</tt> rules, the
5053: <tt>Gather</tt> rule can only appear in rules of the primary view and applies
5054: to all views defined in the presentation schema.</p>
1.18 cvs 5055: <pre> 'Gather' ':' Boolean .</pre>
5056: </div>
1.1 cvs 5057:
1.18 cvs 5058: <div class="subsection">
1.30 cvs 5059: <h3><a name="sectc4224">Visibility</a></h3>
1.1 cvs 5060:
1.34 cvs 5061: <p>The visibility property is used to control which elements should or should
1.1 cvs 5062: not be displayed, based on context. An element can have different
5063: visibilities in different views. If an element's visibility is zero for a
5064: view, that element is not displayed in that view and does not occupy any space
1.18 cvs 5065: (its extents are zero).</p>
1.30 cvs 5066:
5067: <p>Visibility takes non-negative integer values (positive or zero). If values
1.1 cvs 5068: greater than 1 are used, they allow the user to choose a degree of visibility
1.34 cvs 5069: and, thus, to see only those boxes whose visibility property exceeds a certain
5070: threshold. This gives the user control over the granularity of the displayed
5071: pictures.</p>
1.30 cvs 5072:
1.34 cvs 5073: <p>The visibility property can be defined as a constant or by inheritance. If
1.1 cvs 5074: defined by inheritance, it cannot be based on the value of the next or
1.18 cvs 5075: previous box. Visibility can only be inherited from above.</p>
1.30 cvs 5076:
5077: <p>If it is a numeric attribute's presentation rule, the visibility can be
1.1 cvs 5078: specified by the attribute's name, in which case the value of the attribute is
1.18 cvs 5079: used.</p>
5080: <pre> 'Visibility' ':' NumberInherit
1.1 cvs 5081: NumberInherit = Integer / AttrID / Inheritance .
1.18 cvs 5082: Integer = NUMBER .</pre>
1.30 cvs 5083:
1.18 cvs 5084: <blockquote class="example">
1.30 cvs 5085: <p><strong>Example:</strong></p>
5086:
5087: <p>Suppose that only <tt>Formula</tt> elements should be displayed in the
5088: <tt>MathView</tt> view. Then, the default rules should include:</p>
5089: <pre>DEFAULT
1.18 cvs 5090: IN MathView Visibility:0;</pre>
1.30 cvs 5091:
1.31 cvs 5092: <p>which makes all elements invisible in the <tt>MathView</tt> view.
1.30 cvs 5093: However, the <tt>Formula</tt> element also has a <tt>Visibility</tt>
5094: rule:</p>
5095: <pre>Formula :
1.18 cvs 5096: IN MathView Visibility:5;</pre>
1.30 cvs 5097:
5098: <p>which makes formulas, and only formulas, visible.</p>
1.18 cvs 5099: </blockquote>
5100: </div>
1.1 cvs 5101:
1.18 cvs 5102: <div class="subsection">
1.34 cvs 5103: <h3><a name="sectc4225">Character style properties</a></h3>
1.1 cvs 5104:
1.34 cvs 5105: <p>Four properties are used to determine which characters are used to display
1.18 cvs 5106: text. They are size, font, style, and underlining.</p>
1.1 cvs 5107:
1.18 cvs 5108: <div class="subsubsection">
1.30 cvs 5109: <h4><a name="sectd42251">Character size</a></h4>
5110:
1.34 cvs 5111: <p>The size property has two effects. First, it is used to specify the actual
5112: size and distance units for boxes defined in <a href="#sectc4217">relative
5113: units</a>. Second, it defines the size of the characters contained in the
5114: box.</p>
1.1 cvs 5115:
1.30 cvs 5116: <p>As a distance or length, the size can be expressed in abstract or absolute
1.1 cvs 5117: units. It can also be inherited. If it is not inherited, it is expressed
1.18 cvs 5118: simply as an integer followed by the <tt>pt</tt> keyword, which indicates that
5119: the size is expressed in typographer's points. The absence of the <tt>pt</tt>
1.1 cvs 5120: keyword indicates that it is in abstract units in which the value 1 represents
5121: the smallest size while the value 16 is the largest size. The relationship
5122: between these abstract sizes and the real character sizes is controlled by a
5123: table which can be modified statically or even dynamically during the
1.18 cvs 5124: execution of the Thot editor.</p>
1.30 cvs 5125:
5126: <p>If the <tt>Size</tt> rule is a numeric attribute's presentation rule, the
1.34 cvs 5127: value of the size property can be specified by the attribute's name, in which
1.30 cvs 5128: case the value of the attribute is used.</p>
5129:
5130: <p><strong>Note:</strong> the only unit available for defining an absolute
5131: size is the typographer's point. Centimeters and inches may not be used.</p>
5132:
5133: <p>If the size is inherited, the rule must specify the relative from which to
5134: inherit and any percentage or difference from that relative's value. A
5135: percentage is indicated by a <tt>*</tt> followed by the value of the
5136: percentage and a <tt>%</tt>. A difference can be expressed in either
5137: typographer's points or in abstract units and the maximum or minimum size can
5138: be specified, but without specifying the unit: it is the same as was specified
5139: for the difference.</p>
5140:
5141: <p>In a numeric attribute's presentation rule, the difference in size or the
1.22 cvs 5142: percentage can be indicated by the attribute's name instead of the numeric
5143: value, which means that the attribute's value should be used as the difference
5144: or percentage. The attribute can also be used as the minimum or maximum size
5145: for a difference.</p>
5146: <pre> 'Size' ':' SizeInherit
5147: SizeInherit = SizeAttr [ 'pt' ] /
5148: Kinship InheritedSize .
5149: InheritedSize ='+' SizeAttr [ 'pt' ]
5150: [ 'Max' MaxSizeAttr ] /
5151: '-' SizeAttr [ 'pt' ]
5152: [ 'Min' MinSizeAttr ] /
5153: '*' PercentSizeAttr '%' /
5154: '=' .
5155: SizeAttr = Size / AttrID .
5156: Size = NUMBER .
5157: MaxSizeAttr = MaxSize / AttrID .
5158: MaxSize = NUMBER .
5159: MinSizeAttr = MinSize / AttrID .
5160: MinSize = NUMBER .
5161: PercentSizeAttr = PercentSize / AttrID .
5162: PercentSize = NUMBER .</pre>
1.30 cvs 5163:
1.18 cvs 5164: <blockquote class="example">
1.30 cvs 5165: <p><strong>Example:</strong></p>
5166:
5167: <p>The rule</p>
5168: <pre>Size : Enclosing - 2 pt Min 7;</pre>
5169:
5170: <p>states that the character size is 2 points less than that of the
5171: enclosing box, but that it may not be less than 7 points, whatever the
5172: enclosing box's value.</p>
5173:
5174: <p>The following rules make the text of a report be displayed with
5175: medium-sized characters (for example, size 5), while the title is displayed
5176: with larger characters and the summary is displayed with smaller
5177: characters:</p>
5178: <pre>Report :
1.1 cvs 5179: Size : 5;
5180: Title :
5181: Size : Enclosing + 2;
5182: Summary :
1.18 cvs 5183: Size : Enclosing - 1;</pre>
1.30 cvs 5184:
5185: <p>Thus, the character sizes in the entire document can be changed by
1.34 cvs 5186: changing the size property of the Report element, while preserving the
1.30 cvs 5187: relationships between the sizes of the different elements.</p>
1.18 cvs 5188: </blockquote>
5189: </div>
5190:
5191: <div class="subsubsection">
1.30 cvs 5192: <h4><a name="sectd42252">Font and character style</a></h4>
1.18 cvs 5193:
1.30 cvs 5194: <p>The <tt>Font</tt> rule determines the font family to be used to display the
1.18 cvs 5195: characters contained in the box, while the <tt>Style</tt> rule determines
1.23 cvs 5196: their style and the <tt>Weight</tt> rule determines their weight. Thot
5197: recognizes three character fonts (Times, Helvetica, and Courier), three
5198: styles: Roman, Italics, and Oblique, and two weights: Normal and Bold.</p>
1.30 cvs 5199:
5200: <p>The font family, style and weight can be specified by a named constant or
5201: can be inherited. For the name of the font family only the first character is
5202: used.</p>
5203:
5204: <p>Only identical inheritance is allowed: the box takes the same font, style
5205: or weight as the box from which it inherits. This is indicated by an equals
1.23 cvs 5206: sign after the kinship specification.</p>
5207: <pre> 'Font' ':' NameInherit /
5208: 'Style' ':' StyleInherit /
5209: 'Weight' ':' WeightInherit /
5210:
5211: NameInherit = Kinship '=' / FontName .
5212: FontName = NAME .
5213: StyleInherit = Kinship '=' /
5214: 'Roman' / 'Italics' / 'Oblique' .
5215: WeightInherit = Kinship '=' /
5216: 'Normal' / 'Bold' .</pre>
1.30 cvs 5217:
1.18 cvs 5218: <blockquote class="example">
1.30 cvs 5219: <p><strong>Example:</strong></p>
5220:
5221: <p>To specify that the summary uses the font family of the rest of the
5222: document, but in the italic style, the following rules are used:</p>
5223: <pre>Summary :
1.1 cvs 5224: BEGIN
5225: Font : Enclosing =;
5226: Style : Italics;
1.18 cvs 5227: END;</pre>
5228: </blockquote>
5229: </div>
5230:
5231: <div class="subsubsection">
1.30 cvs 5232: <h4><a name="sectd42253">Underlining</a></h4>
1.18 cvs 5233:
1.30 cvs 5234: <p>The <tt>Underline</tt> rule is used to specify if the characters contained
5235: in a box should have lines drawn on or near them. There are four underlining
1.18 cvs 5236: styles: <tt>Underlined</tt>, <tt>Overlined</tt>, <tt>CrossedOut</tt>, and
5237: <tt>NoUnderline</tt>. The <tt>Thickness</tt> rule specifies the thickness of
5238: the line, <tt>Thin</tt> or <tt>Thick</tt>.</p>
1.30 cvs 5239:
5240: <p>As with font family and style, only identical inheritance is allowed: the
5241: box has the same underlining type as the box from which it inherits the value.
1.18 cvs 5242: This is indicated by an equals sign after the kinship specification.</p>
5243: <pre> 'Underline' ':' UnderLineInherit /
1.1 cvs 5244: 'Thickness' ':' ThicknessInherit /
5245:
5246: UnderLineInherit = Kinship '=' / 'NoUnderline' /
5247: 'Underlined' /
5248: 'Overlined' / 'CrossedOut' .
1.18 cvs 5249: ThicknessInherit = Kinship '=' / 'Thick' / 'Thin' .</pre>
5250: </div>
5251: </div>
5252:
5253: <div class="subsection">
1.30 cvs 5254: <h3><a name="sectc4226">Stacking order</a></h3>
1.18 cvs 5255:
1.30 cvs 5256: <p>The <tt>Depth</tt> rule is used to define the stacking order of terminal
5257: boxes when multiple boxes at least partially overlap. This rule defines how
1.34 cvs 5258: the depth property, which is zero or a positive integer, is calculated. The
5259: depth property has a value for all boxes. For terminal boxes in the structure
5260: and for presentation boxes, the depth value is used during display and
5261: printing: the boxes with the lowest value overlap those with higher depths.
5262: For non-terminal boxes, the depth is not interpreted during display, but it is
5263: used to calculate the depth of terminal boxes by inheritance.</p>
1.30 cvs 5264:
5265: <p>Like most other rules, the depth rule is defined in the <a
1.18 cvs 5266: href="#sectc427">default rules</a> of each presentation schema. Thus, there
5267: is always a depth value, even when it is not necessary because there is no
5268: overlapping. To avoid useless operations, a zero value can be given to the
1.34 cvs 5269: depth property, which signifies that overlapping is never a problem.</p>
1.30 cvs 5270:
5271: <p>The depth rule has the same form as the <a href="#sectc4224">visibility
1.18 cvs 5272: rule</a>. It can be defined by inheritance or by a constant numeric value.
5273: When the rule is attached to a numeric attribute, it can take the value of
5274: that attribute.</p>
5275: <pre> 'Depth' ':' NumberInherit</pre>
1.30 cvs 5276:
1.18 cvs 5277: <blockquote class="example">
1.30 cvs 5278: <p><strong>Example:</strong></p>
5279:
5280: <p>For a purely textual document, in which overlapping never poses a
5281: problem, a single default <tt>Depth</tt> rule in the presentation schema is
5282: sufficient:</p>
5283: <pre>DEFAULT
1.1 cvs 5284: Depth : 0;
1.18 cvs 5285: ...</pre>
1.30 cvs 5286:
5287: <p>To make the text of examples appear on a light blue background, a
5288: presentation box is defined:</p>
5289: <pre>BOXES
1.1 cvs 5290: BlueBG :
5291: BEGIN
5292: Content : Graphics 'R';
5293: Background : LightBlue3;
5294: FillPattern: backgroundcolor;
5295: Depth : 2;
5296: ...
1.18 cvs 5297: END;</pre>
1.30 cvs 5298:
5299: <p>and is created by the <tt>Example</tt> element, which has the rules:</p>
5300: <pre>RULES
1.1 cvs 5301: Example :
5302: BEGIN
5303: CreateFirst (BlueBG);
5304: Depth : 1;
5305: ...
1.18 cvs 5306: END;</pre>
1.30 cvs 5307:
5308: <p>In this way, the text of an example (if it inherits its depth from its
5309: ancestor) will be superimposed on a light blue background, and not the
5310: reverse).</p>
1.18 cvs 5311: </blockquote>
5312: </div>
5313:
5314: <div class="subsection">
1.30 cvs 5315: <h3><a name="sectc4227">Line style</a></h3>
1.18 cvs 5316:
1.30 cvs 5317: <p>The <tt>LineStyle</tt> rule determines the style of line which should be
5318: used to draw all the elements contained in the box and the box itself, if it
5319: has a <a href="#sectc4230a"><tt>ShowBox</tt> rule</a>. The line style can be
1.18 cvs 5320: indicated by a name (<tt>Solid</tt>, <tt>Dashed</tt>, <tt>Dotted</tt>) or it
1.13 cvs 5321: can be inherited. All elements of the graphic base type are affected by this
1.1 cvs 5322: rule, but it can be attached to any box and transmitted by inheritance to the
1.18 cvs 5323: graphic elements. The border of elements having a <a
5324: href="#sectc4230a"><tt>ShowBox</tt> rule</a> is drawn according to the line
5325: style specified by this rule.</p>
1.30 cvs 5326:
5327: <p>Only identical inheritance is allowed: the box takes the same line style as
1.1 cvs 5328: the box from which it inherits. This is indicated by an equals sign after the
1.18 cvs 5329: kinship specification.</p>
5330: <pre> 'LineStyle' ':' LineStyleInherit
1.1 cvs 5331: LineStyleInherit = Kinship '=' /
1.18 cvs 5332: 'Solid' / 'Dashed' / 'Dotted' .</pre>
1.30 cvs 5333:
1.18 cvs 5334: <blockquote class="example">
1.30 cvs 5335: <p><strong>Example:</strong></p>
5336:
5337: <p>To specify that, in Figures, the graphical parts should be drawn in solid
5338: lines, the Figure element is given a rule using the <tt>Solid</tt> name:</p>
5339: <pre>Figure :
1.18 cvs 5340: LineStyle : Solid;</pre>
1.30 cvs 5341:
5342: <p>and the elements composing figures are given an inheritance rule:</p>
5343: <pre> LineStyle : Enclosing =;</pre>
1.18 cvs 5344: </blockquote>
5345: </div>
5346:
5347: <div class="subsection">
1.30 cvs 5348: <h3><a name="sectc4228">Line thickness</a></h3>
1.18 cvs 5349:
1.30 cvs 5350: <p>The <tt>LineWeight</tt> rule determines the thickness of the lines of all
1.1 cvs 5351: graphical elements which appear in the box, no matter what their line style.
5352: Line thickness can be specified by a constant value or by inheritance. A
5353: constant value is a positive number followed by an optional unit specification
1.18 cvs 5354: (which is absent when using relative units). All available <a
5355: href="#sectc4217">distance units</a> can be used. Line thickness is expressed
5356: in the same way as <a href="#sectd42221">line spacing</a>.</p>
5357: <pre> 'LineWeight' ':' DistOrInherit</pre>
1.30 cvs 5358:
5359: <p>All elements of the graphic base type are affected by this rule, but it can
5360: be attached to any box and transmitted by inheritance to the graphic elements.
1.18 cvs 5361: The border of element having a <a href="#sectc4230a"><tt>ShowBox</tt> rule</a>
5362: is also drawn according to the thickness specified by this rule.</p>
1.30 cvs 5363:
1.18 cvs 5364: <blockquote class="example">
1.30 cvs 5365: <p><strong>Example:</strong></p>
5366:
5367: <p>To specify that, in Figures, the graphical parts should be drawn with
5368: lines 0.3 pt thick, the Figure element is given this rule:</p>
5369: <pre>Figure :
1.18 cvs 5370: LineWeight : 0.3 pt;</pre>
1.30 cvs 5371:
5372: <p>and the elements composing figures are given an inheritance rule:</p>
5373: <pre> LineWeight : Enclosing =;</pre>
1.18 cvs 5374: </blockquote>
5375: </div>
5376:
5377: <div class="subsection">
1.30 cvs 5378: <h3><a name="sectc4229">Fill pattern</a></h3>
1.18 cvs 5379:
1.30 cvs 5380: <p>The <tt>FillPattern</tt> rule determines the pattern used to fill closed
1.1 cvs 5381: graphical elements (circles, rectangles, etc.) which appear in the box. This
1.18 cvs 5382: rule also specifies the pattern used to fill the box associated with elements
5383: having a <a href="#sectc4230a"><tt>ShowBox</tt> rule</a><a>. This pattern can
5384: be indicated by a named constant or by inheritance. The named constant
5385: identifies one of the patterns available in Thot. The names of the available
5386: patterns are: nopattern, foregroundcolor, backgroundcolor, gray1, gray2,
5387: gray3, gray4, gray5, gray6, gray7, horiz1, horiz2, horiz3, vert1, vert2,
5388: vert3, left1, left2, left3, right1, right2, right3, square1, square2, square3,
5389: lozenge, brick, tile, sea, basket.</a></p>
1.30 cvs 5390:
5391: <p>Like the other rules peculiar to graphics, <tt>LineStyle</tt> and
1.18 cvs 5392: <tt>LineWeight</tt>, only elements of the graphic base type are affected by
5393: the <tt>FillPattern</tt> rule, but the rule can be attached to any box and
1.1 cvs 5394: transmitted by inheritance to the graphic elements. As with the other rules
1.18 cvs 5395: specific to graphics, only identical inheritance is allowed.</p>
1.30 cvs 5396:
5397: <p>The <tt>FillPattern</tt> rule can also be used to determine whether or not
1.12 cvs 5398: text characters, symbols and pictures should be colored. For these element
5399: types (text, symbols, and pictures), the only valid values are
1.18 cvs 5400: <tt>nopattern</tt>, <tt>foregroundcolor</tt>, and <tt>backgroundcolor</tt>.
5401: When <tt>FillPattern</tt> has the value <tt>backgroundcolor</tt>, text
5402: characters, symbols, and bitmaps are given the color specified by the <a
5403: href="#sectc4230"><tt>Background</tt> rule</a> which applies to these
5404: elements. When <tt>FillPattern</tt> has the value <tt>foregroundcolor</tt>,
5405: these same elements are given the color specified by the <a
5406: href="#sectc4230"><tt>Foreground</tt> rule</a> which applies to these
5407: elements. In all other case, text characters are not colored.</p>
5408: <pre> 'FillPattern' ':' NameInherit</pre>
1.30 cvs 5409:
1.18 cvs 5410: <blockquote class="example">
1.30 cvs 5411: <p><strong>Example:</strong></p>
5412:
5413: <p>To specify that, in Figures, the closed graphical elements should be
5414: filled with a pattern resembling a brick wall, the Figure element is given
5415: this rule:</p>
5416: <pre>Figure :
1.18 cvs 5417: FillPattern : brick;</pre>
1.30 cvs 5418:
5419: <p>and the elements composing figures are given an inheritance rule:</p>
5420: <pre> FillPattern : Enclosing =;</pre>
1.18 cvs 5421: </blockquote>
5422: </div>
5423:
5424: <div class="subsection">
1.30 cvs 5425: <h3><a name="sectc4230">Colors</a></h3>
1.18 cvs 5426:
1.30 cvs 5427: <p>The <tt>Foreground</tt> and <tt>Background</tt> rules determine the
5428: foreground and background colors of the base elements which appear in the box.
5429: They also control the color of boxes associated with elements having a <a
1.18 cvs 5430: href="#sectc4230a"><tt>ShowBox</tt> rule</a>. These colors can be specified
5431: with a named constant or by inheritance. The named constants specify one of
5432: the available colors in Thot. The available color names can be found in the
1.30 cvs 5433: file <tt>thot.color</tt>. In addition to those names, you can use the keyword
5434: <code>Transparent</code>, to not draw anything.</p>
5435:
5436: <p>The color rules affect the same way all base elements and elements having a
5437: <a href="#sectc4230a"><tt>ShowBox</tt> rule</a>, no matter what their type
5438: (text, graphics, pictures, symbols). The color rules can be associated with
5439: any box and can be transmitted by inheritance to the base elements or the
5440: elements having a <a href="#sectc4230a"><tt>ShowBox</tt> rule</a>. Like the
5441: preceding rules, only inheritance of the same value is allowed.</p>
5442: <pre> 'Foreground' ':' Color
5443: 'Background' ':' Color
5444: Color = 'Transparent' / Link '=' / FontColorName .</pre>
5445:
5446: <p><strong>Note:</strong> text colors only appear for text elements whose <a
1.18 cvs 5447: href="#sectc4229">fill pattern</a> does not prevent the use of color.</p>
1.30 cvs 5448:
1.18 cvs 5449: <blockquote class="example">
1.30 cvs 5450: <p><strong>Example:</strong></p>
5451:
5452: <p>To specify that, in Figures, everything must be drawn in blue on a
5453: background of yellow, the Figure element is given these rules:</p>
5454: <pre>Figure :
1.1 cvs 5455: BEGIN
5456: Foreground : Blue;
5457: Background : Yellow;
5458: Fillpattern : backgroundcolor;
1.18 cvs 5459: END;</pre>
1.30 cvs 5460:
5461: <p>and the elements composing figures are given inheritance rules:</p>
5462: <pre> Foreground : Enclosing =;
1.1 cvs 5463: Background : Enclosing =;
1.18 cvs 5464: FillPattern : Enclosing =;</pre>
5465: </blockquote>
5466: </div>
5467:
5468: <div class="subsection">
1.30 cvs 5469: <h3><a name="sectc4230a">Background color and border</a></h3>
1.18 cvs 5470:
1.30 cvs 5471: <p>Boxes associated with structural elements are normally not visible, but it
5472: is possible to draw their border and/or to paint their area when it is needed.
1.18 cvs 5473: This is achieved by associating the <tt>ShowBox</tt> rule with the concerned
1.13 cvs 5474: element. This rule has no parameter and no value. It is simply written
1.18 cvs 5475: <tt>Showbox;</tt>. It is not inherited nor transmitted to any other element.
5476: It applies only to the element with which it is associated.</p>
5477: <pre> 'ShowBox'</pre>
1.30 cvs 5478:
5479: <p>When an element has a <tt>ShowBox</tt> rule, the border is drawn only if
5480: the <tt>LineWeight</tt> rule that applies to that element has a non-zero value
1.18 cvs 5481: (this value can be inherited). The color, style and thickness of the border
5482: are defined by the <tt>Foreground</tt>, <tt>LineStyle</tt>, and
5483: <tt>LineWeight</tt> rules that apply to the element.</p>
1.30 cvs 5484:
5485: <p>When an element has a <tt>ShowBox</tt> rule, the background of this element
5486: is paint only if the value of the <tt>FillPattern</tt> rule that applies to
5487: that element is not <tt>nopattern</tt>. The pattern and color(s) of the
5488: background are defined by the <tt>FillPattern</tt>, <tt>Background</tt>, and
1.18 cvs 5489: <tt>Foreground</tt> rules that apply to the element.</p>
5490: </div>
5491:
5492: <div class="subsection">
1.30 cvs 5493: <h3><a name="sectc4230b">Background pictures</a></h3>
1.18 cvs 5494:
1.30 cvs 5495: <p>The <tt>BackgroundPicture</tt> rule allows to display a picture as the
1.13 cvs 5496: background of an element. It has a single parameter, the file name of the
1.18 cvs 5497: picture. This is a string delimited by single quotes. If the first character
5498: in this string is '/', it is considered as an absolute path, otherwise the
5499: file is searched for along the schema directory path. This file may contain a
5500: picture in any format accepted by Thot (xbm, xpm, gif, jpeg, png, etc.)</p>
1.30 cvs 5501:
5502: <p>The <tt>BackgroundPicture</tt> and <tt>PictureMode</tt> rules apply only to
1.13 cvs 5503: the element with which they are associated. They are not inherited nor
1.18 cvs 5504: transmitted to children elements.</p>
1.30 cvs 5505:
5506: <p>The background picture has not always the same size as the element's box.
1.13 cvs 5507: There are diffrent ways to fill the element box with the picture. This is
1.18 cvs 5508: specified by the <tt>PictureMode</tt> rule, which should be associated to the
5509: same element. This rule may take one of the following values:</p>
5510: <dl>
1.30 cvs 5511: <dt><tt>NormalSize</tt></dt>
5512: <dd>The picture is centered in the box, and clipped if it is too
5513: large.</dd>
5514: <dt><tt>Scale</tt></dt>
5515: <dd>The picture is zoomed to fit the box size.</dd>
5516: <dt><tt>RepeatX</tt></dt>
5517: <dd>The picture is repeated horizontally to fit the box width.</dd>
5518: <dt><tt>RepeatY</tt></dt>
5519: <dd>The picture is repeated vertically to fit the box height.</dd>
5520: <dt><tt>RepeatXY</tt></dt>
5521: <dd>The picture is repeated both horizontally and vertically to fill the
5522: box.</dd>
1.18 cvs 5523: </dl>
1.30 cvs 5524:
5525: <p>If an element has a <tt>BackgroundPicture</tt> rule and no
1.18 cvs 5526: <tt>PictureMode</tt> rule, the <tt>NormalSize</tt> value is assumed.</p>
5527: <pre> 'BackgroundPicture' ':' FileName /
1.13 cvs 5528: 'PictureMode' ':' PictMode .
5529:
5530: FileName = STRING .
1.18 cvs 5531: PictMode = 'NormalSize' / 'Scale' / 'RepeatXY' / 'RepeatX' / 'RepeatY' .</pre>
1.30 cvs 5532:
5533: <p>The <tt>BackgroundPicture</tt> and <tt>PictureMode</tt> rules apply only to
1.13 cvs 5534: the element with which they are associated. They are not inherited nor
1.18 cvs 5535: transmitted to children elements.</p>
5536: </div>
1.13 cvs 5537:
1.18 cvs 5538: <div class="subsection">
1.30 cvs 5539: <h3><a name="sectc4231">Presentation box content</a></h3>
1.1 cvs 5540:
1.30 cvs 5541: <p>The <tt>Content</tt> rule applies to presentation boxes. It indicates the
1.1 cvs 5542: content given to a box. This content is either a variable's value or a
1.18 cvs 5543: constant value. In the special case of <a href="#sectc4233">header or footer
5544: boxes</a>, the content can also be a structured element type.</p>
1.30 cvs 5545:
5546: <p>If the content is a constant, it can be specified, as in a variable
1.18 cvs 5547: declaration, either by the name of a constant declared in the <tt>CONST</tt>
1.1 cvs 5548: section or by direct specification of the type and value of the box's
1.18 cvs 5549: content.</p>
1.30 cvs 5550:
5551: <p>Similarly, if it is a variable, the name of a variable declared in
1.18 cvs 5552: <tt>VAR</tt> section can be given or the variable may be defined within
5553: parentheses. The content inside the parentheses has the same syntax as a <a
5554: href="#sectc426">variable declaration</a>.</p>
1.30 cvs 5555:
5556: <p>When the content is a structured element type, the name of the element type
5557: is given after the colon. In this case, the box's content is all elements of
1.1 cvs 5558: the named type which are designated by references which are part of the page
1.18 cvs 5559: on which the header or footer with this <tt>Content</tt> rule appears. Only
5560: associated elements can appear in a <tt>Content</tt> rule and the structure
1.1 cvs 5561: must provide references to these elements. Moreover, the box whose content
5562: they are must be a header or footer box generated by a page box of the primary
1.18 cvs 5563: view.</p>
5564: <pre> 'Content' ':' VarConst
1.1 cvs 5565: VarConst = ConstID / ConstType ConstValue /
5566: VarID / '(' FunctionSeq ')' /
1.18 cvs 5567: ElemID .</pre>
1.30 cvs 5568:
5569: <p>A presentation box can have only one <tt>Content</tt> rule, which means
5570: that the content of a presentation box cannot vary from view to view. However,
5571: such an effect can be achieved by creating several presentation boxes, each
5572: with different content and visible in different views.</p>
5573:
5574: <p>The <tt>Content</tt> rule also applies to elements defined as references in
1.1 cvs 5575: the structure schema. In this case, the content defined by the rule must be
5576: a constant. It is this content which appears on the screen or paper to
5577: represent references of the type to which the rule applies. A reference can
1.18 cvs 5578: have a <tt>Content</tt> rule or a <a href="#sectc4234"><tt>Copy</tt> rule</a>
1.1 cvs 5579: for each view. If neither of these rules appears, the reference is displayed
1.18 cvs 5580: as <tt>[*]</tt>, which is equivalent to the rule:</p>
5581: <pre> Content: Text '[*]';</pre>
1.30 cvs 5582:
1.18 cvs 5583: <blockquote class="example">
1.30 cvs 5584: <p><strong>Example:</strong></p>
5585:
5586: <p>The content of the presentation box created to make the chapter number
5587: and section number appear before each section title can be defined by:</p>
5588: <pre>BOXES
1.1 cvs 5589: SectionNumBox :
5590: BEGIN
5591: Content : NumSection;
5592: ...
1.18 cvs 5593: END;</pre>
1.30 cvs 5594:
5595: <p>if the <tt>NumSection</tt> variable has been defined in the variable
5596: definition section of the presentation schema. Otherwise the
5597: <tt>Content</tt> would be written:</p>
5598: <pre>BOXES
1.1 cvs 5599: SectionNumBox :
5600: BEGIN
5601: Content : (VALUE (ChapterCtr, Roman) TEXT '.'
5602: VALUE (SectionCtr, Arabic));
5603: ...
1.18 cvs 5604: END;</pre>
1.30 cvs 5605:
5606: <p>To specify that a page footer should contain all elements of the
5607: <tt>Note</tt> type are referred to in the page, the following rule is
5608: written:</p>
5609: <pre>BOXES
1.1 cvs 5610: NotesFooterBox :
5611: BEGIN
5612: Content : Note;
5613: ...
1.18 cvs 5614: END;</pre>
1.30 cvs 5615:
5616: <p><tt>Note</tt> is defined as an associated element in the structure schema
5617: and NotesFooterBox is created by a page box of the primary view.</p>
1.18 cvs 5618: </blockquote>
5619: </div>
1.1 cvs 5620:
1.18 cvs 5621: <div class="subsection">
1.30 cvs 5622: <h3><a name="sectc4232">Presentation box creation</a></h3>
1.1 cvs 5623:
1.30 cvs 5624: <p>A creation rule specifies that a presentation box should be created when an
1.18 cvs 5625: element of the type to which the rule is attached appears in the document.</p>
1.30 cvs 5626:
5627: <p>A keyword specifies the position, relative to the creating box, at which
5628: the created box will be placed in the structure:</p>
1.18 cvs 5629: <dl>
1.30 cvs 5630: <dt><tt>CreateFirst</tt></dt>
5631: <dd>specifies that the box should be created as the first box of the next
5632: lower level, before any already existing boxes, and only if the
5633: beginning of the creating element is visible;</dd>
5634: <dt><tt>CreateLast</tt></dt>
5635: <dd>specifies that the box should be created as the last box of the next
5636: lower level, after any existing boxes, and only if the end of the
5637: creating element is visible;</dd>
5638: <dt><tt>CreateBefore</tt></dt>
5639: <dd>specifies that the box should be created before the creating box, on
5640: the same level as the creating box, and only if the beginning of the
5641: creating element is visible;</dd>
5642: <dt><tt>CreateAfter</tt></dt>
5643: <dd>specifies that the box should be created after the creating box, on
5644: the same level as the creating box, and only if the beginning of the
5645: creating element is visible;</dd>
5646: <dt><tt>CreateEnclosing</tt></dt>
5647: <dd>specifies that the box should be created at the upper level relatively
5648: to the creating box, and that it must contain that creating box and all
5649: presentation boxes created by the same creating box.</dd>
1.18 cvs 5650: </dl>
1.30 cvs 5651:
5652: <p>This keyword can be followed by the <tt>Repeated</tt> keyword to indicate
5653: that the box must be created for each part of the creating element. These
5654: parts result from the division of the element by page breaks or column
5655: changes. If the <tt>Repeated</tt> keyword is missing, the box is only created
5656: for the first part of the creating element (<tt>CreateFirst</tt> and
1.18 cvs 5657: <tt>CreateBefore</tt> rules) or for the last part (<tt>CreateLast</tt> and
5658: <tt>CreateAfter</tt> rules).</p>
1.30 cvs 5659:
5660: <p>The type of presentation to be created is specified at the end of the rule
1.18 cvs 5661: between parentheses.</p>
1.30 cvs 5662:
5663: <p>Creation rules cannot appear in the <a href="#sectc427">default
5664: presentation rules</a>. The boxes being created should have a
5665: <tt>Content</tt> rule which indicates their <a
5666: href="#sectc4231">content</a>.</p>
5667:
5668: <p>Creation rules can only appear in the block of rules for the primary view;
1.1 cvs 5669: creation is provoked by a document element for all views. However, for each
5670: view, the presentation box is only created if the creating element is itself a
1.34 cvs 5671: box in the view. Moreover, the visibility property of the presentation box can
5672: be adjusted to control the creation of the box on a view-by-view basis.</p>
1.18 cvs 5673: <pre> Creation '(' BoxID ')'
1.1 cvs 5674: Creation = Create [ 'Repeated' ] .
5675: Create ='CreateFirst' / 'CreateLast' /
5676: 'CreateBefore' / 'CreateAfter' /
1.18 cvs 5677: 'CreateEnclosing' .</pre>
1.30 cvs 5678:
1.18 cvs 5679: <blockquote class="example">
1.30 cvs 5680: <p><strong>Example:</strong></p>
5681:
5682: <p>Let us define an object type, called Table, which is composed of a
5683: sequence of columns, all having the same fixed width, where the columns are
5684: separated by vertical lines. There is a line to the left of the first
5685: column and one to the right of the last. Each column has a variable number
1.31 cvs 5686: of cells, placed one on top of the other and separated by horizontal lines.
5687: There are no horizontal lines above the first cell or below the last cell.
1.30 cvs 5688: The text contained in each cell is broken into lines and these lines are
5689: centered horizontally in the cell. The logical structure of this object is
5690: defined by:</p>
5691: <pre>Table = LIST OF (Column);
1.18 cvs 5692: Column = LIST OF (Cell = Text);</pre>
5693:
1.30 cvs 5694: <div class="figure">
5695: <hr>
5696: <pre>| | | |
1.1 cvs 5697: | xx xxxx xxxx |x xxxx xxx xxxxx| x xxx x xxx |
5698: | xxx xxx xxxx x | x xx x xxx | xxxxx xxxx xx |
5699: | xxxxx xxxx |----------------| xxx xxxxx x |
5700: | xxxxx xxx xxxx | xxxx xx xx xxx | xx xx |
5701: | xxx xxxx x xxx | xxxx x xxx x |---------------|
5702: |----------------| xxx xxxx xxxxx | xxxxx xxxxx |
5703: | xxx xxx xxxxxx |----------------| xxx xxxx xxxx |
5704: | xxxx xxxx xx | xxxx xx x xx | xxx xx x xx |
5705: |----------------| xxx xxxxx xxxx | xxxx xxxx xxx |
5706: | xxxxx xxx xxxx | xxxx xx x xx | xxxxx xxx |
1.18 cvs 5707: |xxxx xx x xxxxxx| xxxx xx xxxxxx | xxxxx xxxxx |</pre>
1.19 cvs 5708:
1.30 cvs 5709: <p align="center"><em><a name="table">The design of a table</a></em></p>
5710: <hr>
5711: </div>
5712:
5713: <p>The presentation of the table should resemble the design of the above <a
5714: href="#table">figure</a>. It is defined by the following presentation
5715: schema fragment:</p>
5716: <pre>BOXES
1.1 cvs 5717: VertLine : BEGIN
5718: Width : 0.3 cm;
5719: Height : Enclosing . Height;
5720: VertPos : Top = Enclosing . Top;
5721: HorizPos : Left = Previous . Right;
5722: Content : Graphics 'v';
5723: END;
5724:
5725: HorizLine: BEGIN
5726: Width : Enclosing . Width;
5727: Height : 0.3 cm;
5728: VertPos : Top = Previous . Bottom;
5729: HorizPos : Left = Enclosing . Left;
5730: Content : Graphics 'h';
5731: END;
5732:
5733: RULES
1.6 cvs 5734: Column : BEGIN
5735: CreateBefore (VertLine);
5736: IF LAST CreateAfter (VertLine);
5737: Width : 2.8 cm;
5738: Height : Enclosed . Height;
5739: VertPos : Top = Enclosing . Top;
5740: HorizPos : Left = Previous . Right;
5741: END;
5742:
5743: Cell : BEGIN
5744: IF NOT FIRST CreateBefore (HorizLine);
5745: Width : Enclosing . Width;
5746: Height : Enclosed . Height;
5747: VertPos : Top = Previous . Bottom;
5748: HorizPos : Left = Enclosing . Left;
5749: Line;
5750: Adjust : VMiddle;
1.18 cvs 5751: END;</pre>
1.30 cvs 5752:
5753: <p>It is useful to note that the horizontal position rule of the first
5754: vertical line will not be applied, since there is no preceding box. In this
5755: case, the box is simply placed on the left side of the enclosing box.</p>
1.18 cvs 5756: </blockquote>
5757: </div>
5758:
5759: <div class="subsection">
1.30 cvs 5760: <h3><a name="sectc4233">Page layout</a></h3>
1.18 cvs 5761:
1.30 cvs 5762: <p>The page models specified in the <tt>Page</tt> rule are defined by boxes
1.18 cvs 5763: declared in the <tt>BOXES</tt> section of the presentation schema. Pages are
1.1 cvs 5764: not described as frames which will be filled by the document's text, but as
5765: element are inserted in the flow of the document and which mark the page
5766: breaks. Each of these page break elements contains presentation boxes which
5767: represent the footer boxes of a page followed by header boxes of the next
5768: page. The page box itself is the simple line which separates two pages on the
5769: screen. Both the footer and header boxes placed themselves with respect to
5770: this page box, with the footer being placed above it and the header boxes
1.18 cvs 5771: being placed above it.</p>
1.30 cvs 5772:
5773: <p>The boxes created by a page box are headers and footers and can only place
1.1 cvs 5774: themselves vertically with respect to the page box itself (which is in fact
5775: the separation between two pages). Besides, it is their vertical position
5776: rule which determines whether they are header or footer boxes. Header and
5777: footer boxes must have an explicit vertical position rule (they must not use
1.18 cvs 5778: the default rule).</p>
1.30 cvs 5779:
5780: <p>Footer boxes must have an absolute height or inherit the height of their
1.18 cvs 5781: contents:</p>
5782: <pre>Height : Enclosed . Height;</pre>
1.30 cvs 5783:
5784: <p>A page box must have height and width rules and these two rules must be
1.1 cvs 5785: specified with constant values, expressed in centimeters, inches, or
5786: typographer's points. These two rules are interpreted in a special way for
5787: page boxes: they determine the width of the page and the vertical distance
5788: between two page separators, which is the height of the page and its header
1.18 cvs 5789: and footer together.</p>
1.30 cvs 5790:
5791: <p>A page box should also have vertical and horizontal position rules and
5792: these two rules should specify the position on the sheet of paper of the
5793: rectangle enclosing the page's contents. These two rules must position the
5794: upper left corner of the enclosing rectangle in relation to the upper left
5795: corner of the sheet of paper, considered to be the enclosing element. In both
5796: rules, distances must be expressed in fixed units: centimeters (<tt>cm</tt>),
5797: inches (<tt>in</tt>), or typographer's points (<tt>pt</tt>). Thus, rules
5798: similar to the following should be found in the rules for a page box:</p>
1.18 cvs 5799: <pre>BOXES
1.1 cvs 5800: ThePage :
5801: BEGIN
5802: VertPos : Top = Enclosing . Top + 3 cm;
5803: HorizPos : Left = Enclosing . Left + 2.5 cm;
5804: Width : 16 cm;
5805: Height : 22.5 cm;
1.18 cvs 5806: END;</pre>
1.30 cvs 5807:
5808: <p>When a document must be page broken, the page models to be constructed are
1.18 cvs 5809: defined in the <tt>BOXES</tt> section of the presentation schema by declaring
5810: page boxes and header and footer boxes. Also, the <tt>Page</tt> rule is used
1.1 cvs 5811: to specify to which parts of the document and to which views each model should
1.18 cvs 5812: be applied.</p>
1.30 cvs 5813:
5814: <p>The <tt>Page</tt> rule has only one parameter, given between parentheses
5815: after the <tt>Page</tt> keyword. This parameter is the name of the box which
5816: must serve as the model for page construction. When a <tt>Page</tt> rule is
1.1 cvs 5817: attached to an element type, each time such an element appears in a document,
5818: a page break takes place and the page model indicated in the rule is applied
5819: to all following pages, until reaching the next element which has a
1.18 cvs 5820: <tt>Page</tt> rule.</p>
1.30 cvs 5821:
5822: <p>The <tt>Page</tt> rule applies to only one view; if it appears in the
5823: primary view's block of rules, a <tt>Page</tt> rule applies only to that view.
5824: Thus, different page models can be defined for the full document and for its
5825: table of contents, which is another view of the same document. Some views can
5826: be specified with pages, and other views of the same document can be specified
1.18 cvs 5827: without pages.</p>
5828: <pre> 'Page' '(' BoxID ')'</pre>
5829: </div>
5830:
5831: <div class="subsection">
1.30 cvs 5832: <h3><a name="sectc4234">Box copies</a></h3>
1.18 cvs 5833:
1.30 cvs 5834: <p>The <tt>Copy</tt> rule can be used for an element which is defined as a
1.7 cvs 5835: reference in the structure schema. In this case, the rule specifies, between
1.18 cvs 5836: parenthesis, the name of the box (declared in the <tt>BOXES</tt> section)
1.1 cvs 5837: which must be produced when this reference appears in the structure of a
5838: document. The box produced is a copy (same contents, but possible different
5839: presentation) of the box type indicated by the parameter between parentheses,
5840: and which is in the element designated by the reference. The name of a box
5841: can be replaced by type name. Then what is copied is the contents of the
1.18 cvs 5842: element of this type which is inside the referenced element.</p>
1.30 cvs 5843:
5844: <p>Whether a box name or type name is given, it may be followed by the name of
5845: a structure schema between parentheses. This signifies that the box or type
5846: is defined in the indicated structure schema and not in the structure schema
5847: with which the rule's presentation schema is associated.</p>
5848:
5849: <p>The <tt>Copy</tt> rule can also be applied to a presentation box. If the
1.1 cvs 5850: presentation box was created by a reference attribute, the rule is applied as
5851: in the case of a reference element: the contents of the box having the
1.18 cvs 5852: <tt>Copy</tt> rule are based on the element designated by the reference
5853: attribute. For other presentation boxes, the <tt>Copy</tt> rule takes a type
1.1 cvs 5854: name parameter which can be followed, between parentheses, by the name of the
5855: structure schema in which the type is defined, if it is not defined in the
5856: same schema. The contents of the box which has this rule are a copy of the
5857: element of this type which is in the element creating the presentation box, or
5858: by default, the box of this type which precedes the presentation box. This
5859: last facility is used, for example, to define the running titles in headers or
1.18 cvs 5860: footers.</p>
5861: <pre> 'Copy' '(' BoxTypeToCopy ')' .
1.1 cvs 5862: BoxTypeToCopy = BoxID [ ExtStruct ] /
1.6 cvs 5863: ElemID [ ExtStruct ] .
1.18 cvs 5864: ExtStruct = '(' ElemID ')' .</pre>
1.30 cvs 5865:
5866: <p>Like the creation rules, the <tt>Copy</tt> rule cannot appear in the <a
1.18 cvs 5867: href="#sectc427">default presentation rules</a>. Moreover, this rule can only
5868: appear in the primary view's block of rules; the copy rule is applied to all
5869: views.</p>
1.30 cvs 5870:
1.18 cvs 5871: <blockquote class="example">
1.30 cvs 5872: <p><strong>Example:</strong></p>
5873:
5874: <p>If the following definitions are in the structure schema:</p>
5875: <pre>Body = LIST OF (Chapter =
1.1 cvs 5876: BEGIN
5877: ChapterTitle = Text;
5878: ChapterBody = SectionSeq;
5879: END);
1.18 cvs 5880: RefChapter = REFERENCE (Chapter);</pre>
1.30 cvs 5881:
5882: <p>then the following presentation rules (among many other rules in the
5883: presentation schema) can be specified:</p>
5884: <pre>COUNTERS
1.1 cvs 5885: ChapterCtr : RANK OF Chapter;
5886: BOXES
5887: ChapterNumber :
5888: BEGIN
5889: Content : (VALUE (ChapterCtr, URoman));
5890: ...
5891: END;
5892: RULES
5893: Chapter :
5894: BEGIN
5895: CreateFirst (ChapterNumber);
5896: ...
5897: END;
5898: RefChapter :
5899: BEGIN
5900: Copy (ChapterNumber);
5901: ...
1.18 cvs 5902: END;</pre>
1.30 cvs 5903:
5904: <p>which makes the number of the chapter designated by the reference appear
5905: in uppercase roman numerals, in place of the reference to a chapter itself.
5906: Alternatively, the chapter title can be made to appear in place of the
5907: reference by writing this <tt>Copy</tt>rule:</p>
5908: <pre> Copy (ChapterTitle);</pre>
5909:
5910: <p>To define a header box, named <tt>RunningTitle</tt>, which contains the
5911: title of the current chapter, the box's contents are defined in this
5912: way:</p>
5913: <pre>BOXES
1.1 cvs 5914: RunningTitle :
1.18 cvs 5915: Copy (ChapterTitle);</pre>
5916: </blockquote>
5917: </div>
5918: </div>
5919: <hr>
5920: </div>
1.1 cvs 5921:
1.18 cvs 5922: <div class="chapter">
5923: <h1><a name="sect5">The T language</a></h1>
1.1 cvs 5924:
1.18 cvs 5925: <div class="section">
1.30 cvs 5926: <h2><a name="sectb51">Document translation</a></h2>
1.1 cvs 5927:
1.30 cvs 5928: <p>Because of its document model, Thot can produce documents in a high-level
1.18 cvs 5929: abstract form. This form, called the <em>canonical form</em> is specific to
1.1 cvs 5930: Thot; it is well suited to the editor's manipulations, but it does not
5931: necessarily suit other operations which might be applied to documents. Because
5932: of this, the Thot editor offers the choice of saving documents in its own form
5933: (the canonical form) or a format defined by the user. In the latter case, the
5934: Thot document is transformed by the translation program. This facility can
5935: also be used to export documents from Thot to systems using other
1.18 cvs 5936: formalisms.</p>
1.1 cvs 5937:
1.18 cvs 5938: <div class="subsection">
1.30 cvs 5939: <h3><a name="sectc511">Translation principles</a></h3>
1.1 cvs 5940:
1.30 cvs 5941: <p>Document translation allows the export of documents to other systems which
5942: do not accept Thot's canonical form. Translation can be used to export
5943: document to source-based formatters like T<sub><big>E</big></sub>X,
1.18 cvs 5944: L<sup>A</sup>T<sub><big>E</big></sub>X, and <tt>troff</tt>. It can also be
1.1 cvs 5945: used to translate documents into interchange formats like SGML or HTML. To
5946: allow the widest range of possible exports, Thot does not limit the choice of
5947: translations, but rather allows the user to define the formalisms into which
1.18 cvs 5948: documents can be translated.</p>
1.30 cvs 5949:
5950: <p>For each document or object class, a set of translation rules can be
5951: defined, specifying how the canonical form should be transformed into a given
1.18 cvs 5952: formalism. These translation rules are grouped into <em>translation
5953: schemas</em>, each schema containing the rules necessary to translate a
1.1 cvs 5954: generic logical structure (document or object structure) into a particular
5955: formalism. The same generic logical structure can have several different
5956: translation schemas, each defining translation rules for a different
1.18 cvs 5957: formalism.</p>
1.30 cvs 5958:
5959: <p>Like presentation schemas, translation schemas are generic. Thus, they
5960: apply to an entire object or document class and permit translation of all
5961: documents or objects of that class.</p>
1.18 cvs 5962: </div>
1.1 cvs 5963:
1.18 cvs 5964: <div class="subsection">
1.30 cvs 5965: <h3><a name="sectc512">Translation procedure</a></h3>
1.1 cvs 5966:
1.30 cvs 5967: <p>The translator works on the specific logical structure of the document
5968: being translated. It traverses the primary tree of this logical structure in
1.1 cvs 5969: pre-order and, at each node encountered, it applies the corresponding
5970: translation rules defined in the translation schema. Translation can be
1.18 cvs 5971: associated:</p>
5972: <ul>
1.30 cvs 5973: <li>with element types defined in the structure schema,</li>
5974: <li>with global or local attributes defined in the structure schema,</li>
5975: <li>with specific presentation rules,</li>
5976: <li>with the content of the leaves of the structure (characters, symbols
5977: and graphical elements)</li>
1.18 cvs 5978: </ul>
1.30 cvs 5979:
5980: <p>Thus, for each node, the translator applies all rules associated with the
1.1 cvs 5981: element type, all rules associated with each attribute (local or global)
5982: carried by the element, and if the element is a leaf of the tree, it also
1.10 cvs 5983: applies translation rules for characters, symbols, or graphical elements,
1.18 cvs 5984: depending on the type of the leaf.</p>
1.30 cvs 5985:
5986: <p>Rules associated with the content of leaves are different from all other
1.1 cvs 5987: rules: they specify only how to translate character strings, symbols, and
5988: graphical elements. All other rules, whether associated with element types,
5989: with specific presentation rules or with attributes, are treated similarly.
1.18 cvs 5990: These rules primarily allow:</p>
5991: <ul>
1.30 cvs 5992: <li>generation of a text constant or variable before or after the contents
5993: of an element,</li>
5994: <li>modification of the order in which elements appear after
5995: translation,</li>
5996: <li>removal of an element in the translated document,</li>
5997: <li>and writing messages on the user's terminal during translation.</li>
1.18 cvs 5998: </ul>
5999: </div>
6000: </div>
1.1 cvs 6001:
1.18 cvs 6002: <div class="section">
1.30 cvs 6003: <h2><a name="sectb52">Translation definition language</a></h2>
1.1 cvs 6004:
1.30 cvs 6005: <p>Translation schemas are written in a custom language, called T, which is
1.1 cvs 6006: described in the rest of this chapter. The grammar of T is specified using
1.18 cvs 6007: the same <a href="#sectc321">meta-language</a> as was used for the S and P
1.1 cvs 6008: languages and the translation schemas are written using the same conventions
6009: as the structure and presentation schemas. In particular, the keywords of the
6010: T language (the stings between apostrophes in the following syntax rules) can
6011: be written in any combination of upper-case and lower-case letters, but
6012: identifiers created by the programmer must always be written in the same
1.18 cvs 6013: way.</p>
1.1 cvs 6014:
1.18 cvs 6015: <div class="subsection">
1.30 cvs 6016: <h3><a name="sectc521">Organization of a translation schema</a></h3>
1.1 cvs 6017:
1.30 cvs 6018: <p>A translation schema is begun by the <tt>TRANSLATION</tt> keyword and is
1.18 cvs 6019: terminated by the <tt>END</tt> keyword. The <tt>TRANSLATION</tt> keyword is
1.1 cvs 6020: followed by the name of the generic structure for which a translation is being
6021: defined and a semicolon. This name must be identical to the name which
1.18 cvs 6022: appears after the <tt>STRUCTURE</tt> keyword in the corresponding structure
6023: schema.</p>
1.30 cvs 6024:
6025: <p>After this declaration of the structure, the following material appears in
1.18 cvs 6026: order:</p>
6027: <ul>
1.30 cvs 6028: <li>the length of lines produced by the translation,</li>
6029: <li>the character delimiting the end of the line,</li>
6030: <li>the character string which the translator will insert if it must
6031: line-break the translated text,</li>
6032: <li>declarations of
6033: <ul>
6034: <li>buffers,</li>
6035: <li>counters,</li>
6036: <li>constants,</li>
6037: <li>variables,</li>
6038: </ul>
6039: </li>
6040: <li>translation rules associated with element types,</li>
6041: <li>translation rules associated with attributes,</li>
6042: <li>translation rules associated with specific presentation rules,</li>
6043: <li>translation rules associated with characters strings, symbols and
6044: graphical elements.</li>
1.18 cvs 6045: </ul>
1.30 cvs 6046:
6047: <p>Each of these sections is introduced by a keyword followed by a sequence of
1.1 cvs 6048: declarations. All of these sections are optional, expect for the translation
1.18 cvs 6049: rules associated with element types. Many <tt>TEXTTRANSLATE</tt> sections can
1.1 cvs 6050: appear, each defining the rules for translating character strings of a
1.18 cvs 6051: particular alphabet.</p>
6052: <pre> TransSchema ='TRANSLATION' ElemID ';'
1.1 cvs 6053: [ 'LINELENGTH' LineLength ';' ]
6054: [ 'LINEEND' CHARACTER ';' ]
6055: [ 'LINEENDINSERT' STRING ';' ]
6056: [ 'BUFFERS' BufferSeq ]
6057: [ 'COUNTERS' CounterSeq ]
6058: [ 'CONST' ConstSeq ]
6059: [ 'VAR' VariableSeq ]
6060: 'RULES' ElemSeq
6061: [ 'ATTRIBUTES' AttrSeq ]
6062: [ 'PRESENTATION' PresSeq ]
1.30 cvs 6063: < 'TEXTTRANSLATE' TextTransSeq >
1.1 cvs 6064: [ 'SYMBTRANSLATE' TransSeq ]
6065: [ 'GRAPHTRANSLATE' TransSeq ]
1.18 cvs 6066: 'END' .</pre>
6067: </div>
1.1 cvs 6068:
1.18 cvs 6069: <div class="subsection">
1.30 cvs 6070: <h3><a name="sectc522">Line length</a></h3>
1.1 cvs 6071:
1.30 cvs 6072: <p>If a <tt>LINELENGTH</tt> instruction is present after the structure
1.1 cvs 6073: declaration, the translator divides the text it produces into lines, each line
6074: having a length less than or equal to the integer which follows the
1.18 cvs 6075: <tt>LINELENGTH</tt> keyword. This maximum line length is expressed as a
1.1 cvs 6076: number of characters. The end of the line is marked by the character defined
1.18 cvs 6077: by the <tt>LINEEND</tt> instruction. When the translator breaks the lines on
1.1 cvs 6078: a space character in generated text, this space will be replaced by the
1.18 cvs 6079: character string defined by the <tt>LINEENDINSERT</tt> instruction.</p>
1.30 cvs 6080:
6081: <p>If the <tt>LINEEND</tt> instruction is not defined then the linefeed
6082: character (octal code 12) is used as the default line end character. If the
1.18 cvs 6083: <tt>LINEENDINSERT</tt> instruction is not defined, the linefeed character is
6084: inserted at the end of the produced lines. If there is no <tt>LINELENGTH</tt>
1.1 cvs 6085: instruction, the translated text is not divided into lines. Otherwise, if the
6086: translation rules generate line end marks, these marks remain in the
6087: translated text, but the length of the lines is not controlled by the
1.18 cvs 6088: translator.</p>
6089: <pre> LineLength = NUMBER .</pre>
1.30 cvs 6090:
1.18 cvs 6091: <blockquote class="example">
1.30 cvs 6092: <p><strong>Example:</strong></p>
6093:
6094: <p>To limit the lines produced by the translator to a length of 80
6095: characters, the following rule is written at the beginning of the
6096: translation schema.</p>
6097: <pre>LineLength 80;</pre>
1.18 cvs 6098: </blockquote>
6099: </div>
1.1 cvs 6100:
1.18 cvs 6101: <div class="subsection">
1.30 cvs 6102: <h3><a name="sectc523">Buffers</a></h3>
1.1 cvs 6103:
1.30 cvs 6104: <p>A buffer is a unit of memory managed by the translator, which can either
1.18 cvs 6105: contain text read from the terminal during the translation (see the <a
6106: href="#sectc5212"><tt>Read</tt> rule</a>), or the name of the last picture
1.1 cvs 6107: (bit-map) encountered by the translator in its traversal of the document.
1.2 cvs 6108: Remember the pictures are stored in files that are separate for the document
1.1 cvs 6109: files and that the canonical form contains only the names of the files in
1.18 cvs 6110: which the pictures are found.</p>
1.30 cvs 6111:
6112: <p>Thus, there are two types of buffers: buffers for reading from the
6113: terminal (filled by the <tt>Read</tt> rule) and the buffer of picture names
6114: (containing the name of the last picture encountered). A translation schema
6115: can use either type, one or several read buffers and one (and only one)
6116: picture name buffer.</p>
6117:
6118: <p>If any buffers are used, the <tt>BUFFERS</tt> keyword must be present,
1.1 cvs 6119: followed by declarations of every buffer used in the translation schema. Each
6120: buffer declaration is composed only of the name of the buffer, chosen freely
1.2 cvs 6121: by the programmer. The picture name buffer is identified by the
1.18 cvs 6122: <tt>Picture</tt> keyword, between parentheses, following the buffer name. The
6123: <tt>Picture</tt> keyword may only appear once. Each buffer declaration is
6124: terminated by a semicolon.</p>
1.30 cvs 6125: <pre> BufferSeq = Buffer < Buffer > .
1.1 cvs 6126: Buffer = BufferID [ '(' 'Picture' ')' ] ';' .
1.18 cvs 6127: BufferID = NAME .</pre>
1.30 cvs 6128:
1.18 cvs 6129: <blockquote class="example">
1.30 cvs 6130: <p><strong>Example:</strong></p>
6131:
6132: <p>The following buffer declarations create a picture name buffer named
6133: <tt>pictureName</tt> and a read buffer named <a
6134: name="destname"><tt>DestName</tt></a>:</p>
6135: <pre>BUFFERS
1.18 cvs 6136: pictureName (Picture); DestName;</pre>
6137: </blockquote>
6138: </div>
1.1 cvs 6139:
1.18 cvs 6140: <div class="subsection">
1.30 cvs 6141: <h3><a name="sectc524">Counters</a></h3>
6142:
6143: <p>Certain translation rules generate text that varies according to the
6144: context of the element to which the rules apply. Variable text is defined
6145: either in the <a href="#sectc526"><tt>VAR</tt> section</a> of the translation
6146: schema or in the rule itself (see the <tt>Create</tt> and <tt>Write</tt>
6147: rules). Both types of definition rely on counters for the calculation of
6148: variable material.</p>
6149:
6150: <p>There are two types of counter: counters whose value is explicitely
6151: computed by applying <a href="#sectc5221"><tt>Set</tt> and <tt>Add</tt>
6152: rules</a>, and counters whose value is computed by a function associated with
6153: the counter. Those functions allow the same calculations as can be used in
6154: presentation schemas. As in a presentation schema, counters must be defined in
6155: the <tt>COUNTERS</tt> section of the translation schema before they are
6156: used.</p>
6157:
6158: <p>When counters are used in a translation schema, the <tt>COUNTERS</tt>
6159: keyword is followed by the declarations of every counter used. Each
6160: declaration is composed of the counter's name possibly followed by a colon and
6161: the counting function to be used for the counter. The declaration is
6162: terminated by a semi-colon. If the counter is explicitely computed by
6163: <tt>Set</tt> and <tt>Add</tt> rules, no counting function is indicated. If a
6164: counting function is indicated, <tt>Set</tt> and <tt>Add</tt> rules cannot be
6165: applied to that counter.</p>
1.1 cvs 6166:
1.30 cvs 6167: <p>The counting function indicates how the counter's value will be computed.
1.18 cvs 6168: Three functions are available: <tt>Rank</tt>, <tt>Rlevel</tt>, and
6169: <tt>Set</tt>.</p>
6170: <ul>
1.30 cvs 6171: <li><tt>Rank of ElemID</tt> indicates that the counter's value is the rank
6172: of the element of type <tt>ElemID</tt> which encloses the element for
6173: which the counter is being evaluated. For the purposes of this function,
6174: an element of type <tt>ElemID</tt> is considered to enclose itself. This
6175: function is primarily used when the element of type <tt>ElemID</tt> is
6176: part of an aggregate or list, in which case the counter's value is the
6177: element's rank in its list or aggregate. Note that, unlike the
6178: <tt>Rank</tt> function for presentation schemas, the <tt>Page</tt> keyword
6179: cannot be used in place of the <tt>ElemID</tt>.
6180: <p>The type name <tt>ElemID</tt> can be followed by an integer. That
6181: number represents the relative level, among the ancestors of the concerned
6182: element, of the element whose rank is asked. If that relative level
6183: <i>n</i> is unsigned, the <i>n<sup>th</sup></i> element of type
6184: <tt>ElemID</tt> encountered when travelling the logical structure from the
6185: root to the concerned element is taken into account. If the relative
6186: level is negative, the logical structure is travelled in the other
6187: direction, from the concerned element to the root.</p>
6188: </li>
6189: <li><tt>Rlevel of ElemID</tt> indicates that the counter's values is the
6190: relative level in the tree of the element for which the counter is being
6191: evaluated. The counter counts the number of elements of type
6192: <tt>ElemID</tt> which are found on the path between the root of the
6193: document's logical structure tree and the element (inclusive).</li>
6194: <li><tt>Set n on Type1 Add m on Type2</tt> indicates that the counter's
6195: value is calculated as follows: in traversing the document from the
6196: beginning to the element for which the counter is being evaluated, the
6197: counter is set to the value <tt>n</tt> each time a <tt>Type1</tt> element
6198: is encountered and is incremented by the amount <tt>m</tt> each time a
6199: <tt>Type2</tt> element is encountered. The initial value <tt>n</tt> and
6200: the increment <tt>m</tt> are integers.</li>
6201: </ul>
6202:
6203: <p>As in a presentation schema, the <tt>Rank</tt> and <tt>Set</tt> functions
6204: can be modified by a numeric attribute which changes their initial value. This
6205: is indicated by the <tt>Init</tt> keyword followed by the numeric attribute's
1.18 cvs 6206: name. The <tt>Set</tt> function takes the value of the attribute instead of
6207: the <tt>InitValue</tt> (<tt>n</tt>). For the <tt>Rank</tt> function, the
1.1 cvs 6208: value of the attribute is considered to be the rank of the first element of
6209: the list (rather than the normal value of 1). Subsequent items in the list
6210: have their ranks shifted accordingly. In both cases, the attribute must be
1.18 cvs 6211: numeric and must be a local attribute of the root of the document itself.</p>
1.30 cvs 6212: <pre> CounterSeq = Counter < Counter > .
1.1 cvs 6213: Counter = CounterID [ ':' CounterFunc ] ';' .
6214: CounterID = NAME .
6215: CounterFunc = 'Rank' 'of' ElemID [ SLevelAsc ]
6216: [ 'Init' AttrID ] /
6217: 'Rlevel' 'of' ElemID /
6218: 'Set' InitValue 'On' ElemID
6219: 'Add' Increment 'On' ElemID
6220: [ 'Init' AttrID ] .
6221: SLevelAsc = [ '-' ] LevelAsc .
6222: LevelAsc = NUMBER .
6223: InitValue = NUMBER .
6224: Increment = NUMBER .
6225: ElemID = NAME .
1.18 cvs 6226: AttrID = NAME .</pre>
1.30 cvs 6227:
1.18 cvs 6228: <blockquote class="example">
1.30 cvs 6229: <p><strong>Example:</strong></p>
6230:
6231: <p>If the body of a chapter is defined in the structure schema by:</p>
6232: <pre>Chapter_Body = LIST OF
1.1 cvs 6233: (Section = BEGIN
6234: Section_Title = Text;
6235: Section_Body = BEGIN
6236: Paragraphs;
6237: Section;
6238: END;
6239: END
1.18 cvs 6240: );</pre>
1.30 cvs 6241:
6242: <p>(sections are defined recursively), a counter can be defined giving the
6243: <a name="sectnum">number of a section</a> within its level in the
6244: hierarchy:</p>
6245: <pre>COUNTERS
1.18 cvs 6246: SectionNumber : Rank of Section;</pre>
1.30 cvs 6247:
6248: <p>A counter holding the hierarchic level of a section:</p>
6249: <pre> SectionLevel : Rlevel of Section;</pre>
6250:
6251: <p>A <a name="uniquenum">counter</a> which sequentially numbers all the
6252: document's sections, whatever their hierarchic level:</p>
6253: <pre> UniqueSectNum : Set 0 on Document Add 1 on Section;</pre>
1.18 cvs 6254: </blockquote>
6255: </div>
1.1 cvs 6256:
1.18 cvs 6257: <div class="subsection">
1.30 cvs 6258: <h3><a name="sectc525">Constants</a></h3>
1.1 cvs 6259:
1.30 cvs 6260: <p>A common feature of translation rules is the generation of constant text.
6261: This text can be defined in the rule that generates it (see for example the <a
1.18 cvs 6262: href="#sectc5210"><tt>Create</tt></a> and <a
6263: href="#sectc5211"><tt>Write</tt></a> rules); but it can also be defined once
6264: in the constant declaration section and used many times in different rules.
6265: The latter option is preferable when the same text is used in several rules or
6266: several <a href="#sectc526">variables</a>.</p>
1.30 cvs 6267:
6268: <p>The <tt>CONST</tt> keyword begins the constant declaration section of the
1.1 cvs 6269: translation schema. It must be omitted if no constants are declared. Each
6270: constant declaration is composed of the constant name, an equals sign, and the
6271: constant's value, which is a character string between apostrophes. A constant
1.18 cvs 6272: declaration is terminated by a semicolon.</p>
1.30 cvs 6273: <pre> ConstSeq = Const < Const > .
1.1 cvs 6274: Const = ConstID '=' ConstValue ';' .
6275: ConstID = NAME .
1.18 cvs 6276: ConstValue = STRING .</pre>
1.30 cvs 6277:
1.18 cvs 6278: <blockquote class="example">
1.30 cvs 6279: <p><strong><a name="levelexample">Example:</a></strong></p>
6280:
6281: <p>The following rule assigns the name <tt>TxtLevel</tt> to the character
6282: string ``Level'':</p>
6283: <pre>CONST
1.18 cvs 6284: TxtLevel = 'Level';</pre>
6285: </blockquote>
6286: </div>
1.1 cvs 6287:
1.18 cvs 6288: <div class="subsection">
1.30 cvs 6289: <h3><a name="sectc526">Variables</a></h3>
1.1 cvs 6290:
1.30 cvs 6291: <p>Variables allow to define variable text which is generated by the
1.18 cvs 6292: <tt>Create</tt> and <tt>Write</tt> rules. They are also used to define file
6293: names which are used in the <tt>Create</tt>, <tt>ChangeMainFile</tt>,
6294: <tt>RemoveFile</tt>, and <tt>Indent</tt> rules. Variables can be defined
6295: either in the <tt>VAR</tt> section of the translation schema or directly in
6296: the rules which use them. Variables that define file names must be declared
6297: in the <tt>VAR</tt> section, and when the same variable is used several times
6298: in the translation schema, it makes sense to define it globally in the
6299: <tt>VAR</tt> section. This section is only present if at least one variable
6300: is defined globally.</p>
1.30 cvs 6301:
6302: <p>After the <tt>VAR</tt> keyword, each global variable is defined by its
6303: name, a colon separator and a sequence of functions (at least one function).
6304: Each variable definition is terminated by a semicolon. Functions determine the
1.1 cvs 6305: different parts which together give the value of the variable. The value is
6306: obtained by concatenating the strings produced by each of the functions. Seven
6307: types of functions are available. Each variable definition may use any number
1.18 cvs 6308: of functions of each type.</p>
6309: <ul>
1.30 cvs 6310: <li>The function <tt>Value(Counter)</tt>returns a string representing the
6311: value taken by the counter when it is evaluated for the element in whose
6312: rule the variable is used. The counter must have been declared in the
6313: <tt>COUNTERS</tt> section of the translation schema. When the counter is
6314: expressed in arabic numerals, the counter name can be followed by a colon
6315: and an integer indicating a minimum length (number of characters) for the
6316: string; if the counter's value is normally expressed with fewer characters
6317: than the required minimum, zeroes are added to the front of the string to
6318: achieve the minimum length.
6319: <p>By default, the counter value is written in arabic digits. If another
6320: representation of that value is needed, the counter name must be followed
6321: by a comma and one of the following keywords:</p>
6322: <ul>
6323: <li><tt>Arabic</tt>: arabic numerals (default value),</li>
6324: <li><tt>LRoman</tt>: lower-case roman numerals,</li>
6325: <li><tt>URoman</tt>: upper-case roman numerals,</li>
6326: <li><tt>Uppercase</tt>: upper-case letter,</li>
6327: <li><tt>Lowercase</tt>: lower-case letter.</li>
6328: </ul>
6329: </li>
6330: <li>The function <tt>FileDir</tt>, without parameter, returns a string
6331: representing the name of the directory of the output file that has been
6332: given as a parameter to the translation program. The string includes a
6333: character '/' at the end.</li>
6334: <li>The function <tt>FileName</tt>, without parameter, returns a string
6335: representing the name of the output file that has been given as a
6336: parameter to the translation program. The file extension (the character
6337: string that terminate the file name, after a dot) is not part of that
6338: string.</li>
6339: <li>The function <tt>Extension</tt>, without parameter, returns a string
6340: representing the extension of the file name. That string is empty if the
6341: file name that has been given as a parameter to the translation program
6342: has no extension. If there is an extension, its first character is a
6343: dot.</li>
6344: <li>The function <tt>DocumentName</tt>, without parameter, returns a string
6345: representing the name of the document being translated.</li>
6346: <li>The function <tt>DocumentDir</tt>, without parameter, returns a string
6347: representing the directory containing the document being translated.</li>
6348: <li>The function formed by the name of a constant returns that constant's
6349: value.</li>
6350: <li>The function formed by a character string between apostrophes returns
6351: that string.</li>
6352: <li>The function formed by the name of a buffer returns the contents of that
6353: buffer. If the named buffer is the picture buffer, then the name of the
6354: last picture encountered is returned. Otherwise, the buffer is a read
1.31 cvs 6355: buffer and the value returned is text previously read from the terminal.
1.30 cvs 6356: If the buffer is empty (no picture has been encountered or the
6357: <tt>Read</tt> rule has not been executed for the buffer), then the empty
6358: string is returned.</li>
6359: <li>The function formed by an attribute name takes the value of the
6360: indicated attribute for the element to which the variable applies. If the
6361: element does not have that attribute, then the element's ancestor are
6362: searched toward the root of the tree. If one of the ancestors does have
6363: the attribute then its value is used. If no ancestors have the attribute,
6364: then the value of the function is the empty string.</li>
1.18 cvs 6365: </ul>
1.30 cvs 6366: <pre> VariableSeq = Variable < Variable > .
6367: Variable = VarID ':' Function < Function > ';' .
1.1 cvs 6368: VarID = NAME .
6369: Function ='Value' '(' CounterID [ ':' Length ]
6370: [ ',' CounterStyle ] ')' /
6371: 'FileDir' / 'FileName' / 'Extension' /
6372: 'DocumentName' / 'DocumentDir' /
6373: ConstID / CharString /
6374: BufferID / AttrID .
6375: Length = NUMBER .
6376: CounterStyle= 'Arabic' / 'LRoman' / 'URoman' /
6377: 'Uppercase' / 'Lowercase' .
1.18 cvs 6378: CharString = STRING .</pre>
1.30 cvs 6379:
1.18 cvs 6380: <blockquote class="example">
1.30 cvs 6381: <p><strong>Example:</strong></p>
6382:
6383: <p>To create, at the beginning of each section of the translated document,
6384: text composed of the string ``Section'' followed by the section number, the
6385: following <a name="varsectexample">variable definition</a> might be
6386: used:</p>
6387: <pre>VAR
1.18 cvs 6388: SectionVar : 'Section' Value(SectionNumber);</pre>
1.30 cvs 6389:
6390: <p>(see the definition of <a
6391: href="#sectnum"><tt>SectionNumber</tt></a>).</p>
6392:
6393: <p>The following variable definition can be used to create, at the beginning
6394: of each section, the text ``Level'' followed by the hierarchical level of
6395: the section. It used the constant defined above.</p>
6396: <pre> LevelVar : TxtLevel Value(SectionLevel);</pre>
6397:
6398: <p>(see the definitions of <a href="#sectnum"><tt>SectionLevel</tt></a> and
6399: of <a href="#levelexample"><tt>TxtLevel</tt></a>).</p>
6400:
6401: <p>To generate the translation of each section in a different file (see <a
6402: href="#sectc5220">rule <tt>ChangeMainFile</tt></a>), the name of these files
6403: might be defined by the following variable:</p>
6404: <pre> VarOutpuFile : FileName Value(SectionNumber)
1.18 cvs 6405: Extension;</pre>
1.30 cvs 6406:
6407: <p>If <tt>output.txt</tt> is the name of the <a name="varoutputfile">output
6408: file</a> specified when starting the translation program, translated
6409: sections are written in files <tt>output1.txt</tt>, <tt>output2.txt</tt>,
6410: etc.</p>
1.18 cvs 6411: </blockquote>
6412: </div>
6413:
6414: <div class="subsection">
1.30 cvs 6415: <h3><a name="sectc527">Translating structure elements</a></h3>
1.18 cvs 6416:
1.30 cvs 6417: <p>The <tt>RULES</tt> keyword introduces the translation rules which will be
1.1 cvs 6418: applied to the various structured element types. Translation rules can be
6419: specified for each element type defined in the structure schema, including the
1.18 cvs 6420: base types defined implicitly, whose names are <tt>TEXT_UNIT</tt>,
6421: <tt>PICTURE_UNIT</tt>, <tt>SYMBOL_UNIT</tt>, <tt>GRAPHIC_UNIT</tt> and
6422: <tt>PAGE_UNIT</tt>. But it is not necessary to specify rules for every
6423: defined type.</p>
1.30 cvs 6424:
6425: <p>If there are no translation rules for an element type, the elements that it
1.1 cvs 6426: contains (and which may have rules themselves) will still be translated, but
6427: the translator will produce nothing for the element itself. To make the
1.18 cvs 6428: translator completely ignore the content of an element the <a
6429: href="#sectc5217"><tt>Remove</tt> rule</a> must be used.</p>
1.30 cvs 6430:
6431: <p>The translation rules for an element type defined in the structure schema
6432: are written using the name of the type followed by a colon and the list of
1.18 cvs 6433: applicable rules. When the element type is a <a href="#sectd3285">mark
6434: pair</a>, but only in this case, the type name must be preceded by the
6435: <tt>First</tt> or <tt>Second</tt> keyword. This keyword indicates whether the
6436: rules that follow apply to the first or second mark of the pair.</p>
1.30 cvs 6437:
6438: <p>The list of rules can take several forms. It may be a simple
6439: non-conditional rule. It can also be formed by a condition followed by one or
6440: more simple rules. Or it can be a block of rules beginning with the
6441: <tt>BEGIN</tt> keyword and ending with the <tt>END</tt> keyword and a
6442: semicolon. This block of rules can contain one or more simple rules and/or
6443: one or more conditions, each followed by one or more simple rules.</p>
6444: <pre> ElemSeq = TransType < TransType > .
1.1 cvs 6445: TransType = [ FirstSec ] ElemID ':' RuleSeq .
6446: FirstSec = 'First' / 'Second' .
1.30 cvs 6447: RuleSeq = Rule / 'BEGIN' < Rule > 'END' ';' .
1.1 cvs 6448: Rule = SimpleRule / ConditionBlock .
6449: ConditionBlock = 'IF' ConditionSeq SimpleRuleSeq .
1.30 cvs 6450: SimpleRuleSeq = 'BEGIN' < SimpleRule > 'END' ';' /
1.18 cvs 6451: SimpleRule .</pre>
6452: </div>
1.1 cvs 6453:
1.18 cvs 6454: <div class="subsection">
1.30 cvs 6455: <h3><a name="sectc528">Conditional rules</a></h3>
1.1 cvs 6456:
1.30 cvs 6457: <p>In a translation schema, the translation rules are either associated with
1.1 cvs 6458: element types or with attribute values or with a specific presentation. They
6459: are applied by the translator each time an element of the corresponding type
6460: is encountered in the translated document or each time the attribute value is
6461: carried by an element or also, each time the specific translation is attached
6462: to an element. This systematic application of the rules can be relaxed: it is
6463: possible to add a condition to one or more rules, so that these rules are only
1.18 cvs 6464: applied when the condition is true.</p>
1.30 cvs 6465:
6466: <p>A condition begins with the keyword <tt>IF</tt>, followed by a sequence of
1.1 cvs 6467: elementary conditions. Elementary conditions are separated from each other by
1.18 cvs 6468: the <tt>AND</tt> keyword. If there is only one elementary condition, this
1.1 cvs 6469: keyword is absent. The rules are only applied if all the elementary
6470: conditions are true. The elementary condition can be negative; it is then
1.18 cvs 6471: preceded by the <tt>NOT</tt> keyword.</p>
1.30 cvs 6472:
6473: <p>When the translation rule(s) controlled by the condition apply to a
6474: reference element or a reference attribute, an elementary condition can also
6475: apply to element referred by this reference. The <tt>Target</tt> keyword is
6476: used for that purpose. It must appear before the keyword defining the
6477: condition type.</p>
6478:
6479: <p>Depending on their type, some conditions may apply either to the element
6480: with which they are associated, or to one of its ancestor. In the case of an
1.18 cvs 6481: ancestor, the key word <tt>Ancestor</tt> must be used, followed by</p>
6482: <ul>
1.30 cvs 6483: <li>either an integer which represents the number of levels in the tree
6484: between the element and the ancestor of interest,</li>
6485: <li>or the type name of the ancestor of interest. If that type is defined
6486: in a separate structure schema, the name of that schema must follow
6487: between parentheses.</li>
1.18 cvs 6488: </ul>
1.30 cvs 6489:
6490: <p>There is a special case for the parent element, which can be simply written
1.18 cvs 6491: <tt>Parent</tt> instead of <tt>Ancestor 1</tt>.</p>
1.30 cvs 6492:
6493: <p>Only conditions <tt>First</tt>, <tt>Last</tt>, <tt>Referred</tt>,
1.34 cvs 6494: <tt>Within</tt>, <tt>Attributes</tt>, <tt>Presentation</tt>, and those
6495: concerning an attribute or a specific presentation can apply to an ancestor.
6496: Conditions <tt>FirstRef</tt>, <tt>LastRef</tt>, <tt>ExternalRef</tt>,
6497: <tt>Alphabet</tt>, <tt>FirstAttr</tt>, <tt>LastAttr</tt>,
6498: <tt>ComputedPage</tt>, <tt>StartPage</tt>, <tt>UserPage</tt>,
6499: <tt>ReminderPage</tt>, <tt>Empty</tt> cannot be preceded by keywords
6500: <tt>Parent</tt> or <tt>Ancestor</tt>.</p>
1.30 cvs 6501:
6502: <p>In condition <tt>Referred</tt> and in the condition that applies to a named
1.18 cvs 6503: attribute, a symbol '<tt>*</tt>' can indicate that the condition is related
1.5 cvs 6504: only to the element itself. If this symbol is not present, not only the
1.18 cvs 6505: element is considered, but also its ancestor, at any level.</p>
1.30 cvs 6506:
6507: <p>The form of an elementary condition varies according to the type of
1.18 cvs 6508: condition.</p>
1.1 cvs 6509:
1.18 cvs 6510: <div class="subsubsection">
6511: <h4><a name="sectd5281">Conditions based on the logical position of the
6512: element</a></h4>
1.30 cvs 6513:
6514: <p>The condition can be on the position of the element in the document's
6515: logical structure tree. It is possible to test whether the element is the
6516: first (<tt>First</tt>) or last (<tt>Last</tt>) among its siblings or if it is
6517: not the first (<tt>NOT First</tt>) or not the last (<tt>NOT Last</tt>).</p>
6518:
6519: <p>It is also possible to test if the element is contained in an element of a
1.18 cvs 6520: given type (<tt>Within</tt>) or if it is not (<tt>NOT Within</tt>). If that
1.1 cvs 6521: element type is defined in a structure schema which is not the one which
6522: corresponds to the translation schema, the type name of this element must be
6523: followed, between parentheses, by the name of the structure schema which
1.18 cvs 6524: defines it.</p>
1.30 cvs 6525:
6526: <p>If the keyword <tt>Within</tt> is preceded by <tt>Immediately</tt>, the
1.18 cvs 6527: condition is satisfied only if the <em>parent</em> element has the type
6528: indicated. If the word <tt>Immediately</tt> is missing, the condition is
6529: satisfied if any <em>ancestor</em> has the type indicated.</p>
1.30 cvs 6530:
6531: <p>An integer <i>n</i> can appear between the keyword <tt>Within</tt> and the
1.1 cvs 6532: type. It specifies the number of ancestors of the indicated type that must be
6533: present for the condition to be satisfied. If the keyword
1.18 cvs 6534: <tt>Immediately</tt> is also present, the <i>n</i> immediate ancestors of the
6535: element must have the indicated type. The integer <i>n</i> must be positive
1.30 cvs 6536: or zero. It can be preceded by <tt><</tt> or <tt>></tt> to indicate a
1.1 cvs 6537: maximum or minimum number of ancestors. If these symbols are missing, the
1.18 cvs 6538: condition is satisfied only if it exists exactly <i>n</i> ancestors. When
1.30 cvs 6539: this number is missing, it is equivalent to > 0.</p>
6540:
6541: <p>If the condition applies to translation rules associated with an attribute,
1.18 cvs 6542: i.e. if it is in the <tt>ATTRIBUTES</tt> section of the presentation schema,
1.11 cvs 6543: the condition can be simply an element name. Translation rules are then
1.18 cvs 6544: executed only if the attribute is attached to an element of that type. The
6545: keyword <tt>NOT</tt> before the element name indicates that the translation
6546: rules must be executed only if the element is not of the type indicated.</p>
6547: </div>
1.1 cvs 6548:
1.18 cvs 6549: <div class="subsubsection">
1.30 cvs 6550: <h4><a name="sectd5282">Conditions on references</a></h4>
1.1 cvs 6551:
1.30 cvs 6552: <p>References may be taken into account in conditions, which can be based on
6553: the fact that the element, or one of its ancestors (unless symbol <tt>*</tt>
6554: is present), is designated by a at least one reference (<tt>Referred</tt>) or
6555: by none (<tt>NOT Referred</tt>). If the element or attribute to which the
1.1 cvs 6556: condition is attached is a reference, the condition can be based on the fact
6557: that it acts as the first reference to the designated element
1.18 cvs 6558: (<tt>FirstRef</tt>), or as the last (<tt>LastRef</tt>), or as a reference to
6559: an element located in another document (<tt>ExternalRef</tt>). Like all
6560: conditions, conditions on references can be inverted by the <tt>NOT</tt>
6561: keyword.</p>
6562: </div>
6563:
6564: <div class="subsubsection">
1.30 cvs 6565: <h4><a name="sectd5284">Conditions on the alphabets</a></h4>
1.1 cvs 6566:
1.30 cvs 6567: <p>The character string base type (and only this type) can use the condition
1.18 cvs 6568: <tt>Alphabet = a</tt> which indicates that the translation rule(s) should only
1.1 cvs 6569: apply if the alphabet of the character string is the one whose name appears
1.18 cvs 6570: after the equals sign (or is not, if there is a preceding <tt>NOT</tt>
1.1 cvs 6571: keyword). This condition cannot be applied to translation rules of an
1.18 cvs 6572: attribute.</p>
1.30 cvs 6573:
6574: <p>In the current implementation of Thot, the available alphabets are the
1.18 cvs 6575: <tt>Latin</tt> alphabet and the <tt>Greek</tt> alphabet.</p>
6576: </div>
1.1 cvs 6577:
1.18 cvs 6578: <div class="subsubsection">
1.30 cvs 6579: <h4><a name="sectd5285">Conditions on page breaks</a></h4>
1.1 cvs 6580:
1.30 cvs 6581: <p>The page break base type (and only this type) can use the following
1.18 cvs 6582: conditions: <tt>ComputedPage</tt>, <tt>StartPage</tt>, <tt>UserPage</tt>, and
6583: <tt>ReminderPage</tt>. The <tt>ComputedPage</tt> condition indicates that the
1.1 cvs 6584: translation rule(s) should apply if the page break was created automatically
1.18 cvs 6585: by Thot; the <tt>StartPage</tt> condition is true if the page break is
6586: generated before the element by the <tt>Page</tt> rule of the P language; the
6587: <tt>UserPage</tt> condition applies if the page break was inserted by the
6588: user; and the <tt>ReminderPage</tt> is applied if the page break is a reminder
6589: of page breaking.</p>
6590: </div>
1.1 cvs 6591:
1.18 cvs 6592: <div class="subsubsection">
1.30 cvs 6593: <h4><a name="sectd5286">Conditions on the element's content</a></h4>
1.1 cvs 6594:
1.30 cvs 6595: <p>The condition can be based on whether or not the element is empty. An
6596: element which has no children or whose leaves are all empty is considered to
6597: be empty itself. This condition is expressed by the <tt>Empty</tt> keyword,
6598: optionally preceded by the <tt>NOT</tt> keyword.</p>
1.18 cvs 6599: </div>
1.1 cvs 6600:
1.18 cvs 6601: <div class="subsubsection">
6602: <h4><a name="sectd5288">Conditions on the presence of specific presentation
6603: rules</a></h4>
1.30 cvs 6604:
6605: <p>The condition can be based on the presence or absence of specific
6606: presentation rules associated with the translated element, whatever the rules,
6607: their value or their number. This condition is expressed by the keyword
1.18 cvs 6608: <tt>Presentation</tt>, optionally preceded by the <tt>NOT</tt> keyword.</p>
6609: </div>
1.1 cvs 6610:
1.18 cvs 6611: <div class="subsubsection">
6612: <h4><a name="sectd5289">Conditions on the presence of logical
6613: attributes</a></h4>
1.30 cvs 6614:
6615: <p>In the same way, the condition can be based on the presence or absence of
1.1 cvs 6616: attributes associated with the translated elements, no matter what the
1.18 cvs 6617: attributes or their values. The <tt>Attributes</tt> keyword expresses this
6618: condition.</p>
6619: </div>
1.1 cvs 6620:
1.18 cvs 6621: <div class="subsubsection">
1.30 cvs 6622: <h4><a name="sectd52810">Conditions on logical attributes</a></h4>
1.1 cvs 6623:
1.30 cvs 6624: <p>If the condition appears in the translation rules of an attribute, the
1.18 cvs 6625: <tt>FirstAttr</tt> and <tt>LastAttr</tt> keywords can be used to indicate that
1.1 cvs 6626: the rules must only be applied if this attribute is the first attribute for
6627: the translated element or if it is the last (respectively). These conditions
1.18 cvs 6628: can also be inverted by the <tt>NOT</tt> keyword.</p>
1.30 cvs 6629:
6630: <p>Another type of condition can only be applied to the translation rules when
1.18 cvs 6631: the element being processed (or one of its ancestors if symbol <tt>*</tt> is
1.1 cvs 6632: missing) has a certain attribute, perhaps with a certain value or, in
6633: contrast, when the element does not have this attribute with this value. The
6634: condition is specified by writing the name of the attribute after the keyword
1.18 cvs 6635: <tt>IF</tt> or <tt>AND</tt>. The <tt>NOT</tt> keyword can be used to invert
1.1 cvs 6636: the condition. If the translation rules must be applied to any element which
6637: has this attribute (or does not have it, if the condition is inverted) no
6638: matter what the attribute's value, the condition is complete. If, in
6639: contrast, the condition applies to one or more values of the attribute, these
6640: are indicated after the name of the attribute, except for reference attributes
1.18 cvs 6641: which do not have values.</p>
1.30 cvs 6642:
6643: <p>The representation of the values of an <a name="relattr">attribute</a> in a
1.1 cvs 6644: condition depends on the attribute's type. For attributes with enumerated or
6645: textual types, the value (a name or character string between apostrophes,
6646: respectively) is simply preceded by an equals sign. For numeric attributes,
6647: the condition can be based on a single value or on a range of values. In the
6648: case of a unique value, this value (an integer) is simply preceded by an
1.18 cvs 6649: equals sign. Conditions based on ranges of values have several forms:</p>
6650: <ul>
1.30 cvs 6651: <li>all values less than a given value (the value is preceded by a ``less
6652: than'' sign).</li>
6653: <li>all values greater than a given value (the value is preceded by a
6654: ``greater than'' sign).</li>
6655: <li>all values falling in an interval, bounds included. The range of values
6656: is then specified <tt>IN [</tt>Minimum <tt>..</tt>Maximum<tt>]</tt>, where
6657: Minimum and Maximum are integers.</li>
1.18 cvs 6658: </ul>
1.30 cvs 6659:
6660: <p>All numeric values may be negative. The integer is simply preceded by a
6661: minus sign.</p>
6662:
6663: <p>Both local and global attributes can be used in conditions.</p>
1.18 cvs 6664: </div>
1.1 cvs 6665:
1.18 cvs 6666: <div class="subsubsection">
1.30 cvs 6667: <h4><a name="sectd52811">Conditions on specific presentation rules</a></h4>
1.1 cvs 6668:
1.30 cvs 6669: <p>It is possible to apply translation rules only when the element being
1.1 cvs 6670: processed has or does not have a specific presentation rule, possibly with a
6671: certain value. The condition is specified by writing the name of the
1.18 cvs 6672: presentation rule after the keyword <tt>IF</tt> or <tt>AND</tt>. The
6673: <tt>NOT</tt> keyword can be used to invert the condition. If the translation
1.1 cvs 6674: rules must be applied to any element which has this presentation rule (or does
6675: not have it, if the condition is inverted) no matter what the rule's value,
6676: the condition is complete. If, in contrast, the condition applies to one or
6677: more values of the rule, these are indicated after the name of the
1.18 cvs 6678: attribute.</p>
1.30 cvs 6679:
6680: <p>The representation of presentation rule values in a condition is similar to
1.1 cvs 6681: that for attribute values. The representation of these values depend on the
6682: type of the presentation rule. There are three categories of presentation
1.18 cvs 6683: rules:</p>
6684: <ul>
1.30 cvs 6685: <li>those taking numeric values (<tt>Size, Indent, LineSpacing,
6686: LineWeight</tt>),</li>
1.36 ! cvs 6687: <li>those with values taken from a predefined list (<tt>Adjust, Hyphenate,
! 6688: Style, Weight, Font, UnderLine, Thickness, LineStyle</tt>),</li>
1.30 cvs 6689: <li>those whose value is a name (<tt>FillPattern, Background,
6690: Foreground</tt>).</li>
1.18 cvs 6691: </ul>
1.30 cvs 6692:
6693: <p>For presentation rules which take numeric values, the condition can take a
1.1 cvs 6694: unique value or a range of values. In the case of a unique value, this value
6695: (an integer) is simply preceded by an equals sign. Conditions based on ranges
1.18 cvs 6696: of values have several forms:</p>
6697: <ul>
1.30 cvs 6698: <li>all values less than a given value (the value is preceded by a ``less
6699: than'' sign).</li>
6700: <li>all values greater than a given value (the value is preceded by a
6701: ``greater than'' sign).</li>
6702: <li>all values falling in an interval, bounds included. The range of values
6703: is then specified <tt>IN [</tt>Minimum <tt>..</tt>Maximum<tt>]</tt>, where
6704: Minimum and Maximum are integers.</li>
1.18 cvs 6705: </ul>
1.30 cvs 6706:
6707: <p>Values for the <tt>Indent</tt>rule may be negative. The integer is then
1.2 cvs 6708: simply preceded by a minus sign and represents how far the first line starts
1.18 cvs 6709: to the left of the other lines.</p>
1.30 cvs 6710:
6711: <p>For presentation rules whose values are taken from predefined lists, the
6712: value which satisfies the condition is indicated by an equals sign followed by
6713: the name of the value.</p>
6714:
6715: <p>For presentation rule whose values are names, the value which satisfies the
1.1 cvs 6716: condition is indicated by the equals sign followed by the value's name. The
1.18 cvs 6717: names of fill patterns (the <tt>FillPattern</tt> rule) and of colors (the
6718: <tt>Foreground</tt> and <tt>Background</tt> rules) known to Thot are the same
6719: as in the P language.</p>
1.30 cvs 6720:
6721: <p>The syntax of conditions based on the specific presentation is the same as
6722: the syntax used to express the <a href="#sectc5224">translation of specific
1.18 cvs 6723: presentation rules</a>.</p>
1.30 cvs 6724:
6725: <p>When a condition has only one rule, the condition is simply followed by
6726: that rule. If it has several rules, they are placed after the condition
6727: between the keywords <tt>BEGIN</tt> and <tt>END</tt>.</p>
1.18 cvs 6728: <pre> ConditionSeq = Condition [ 'AND' Condition ] .
1.1 cvs 6729: Condition = [ 'NOT' ] [ 'Target' ] Cond .
6730: Cond = CondElem / CondAscend .
6731: CondElem ='FirstRef' / 'LastRef' /
6732: 'ExternalRef' /
6733: 'Alphabet' '=' Alphabet /
6734: 'ComputedPage' / 'StartPage' /
6735: 'UserPage' / 'ReminderPage' /
6736: 'Empty' /
1.11 cvs 6737: ElemID /
1.1 cvs 6738: 'FirstAttr' / 'LastAttr' .
6739: CondAscend = [ Ascend ] CondOnAscend .
6740: Ascend = '*' / 'Parent' / 'Ancestor' LevelOrType .
6741: LevelOrType = CondRelLevel / ElemID [ ExtStruct ] .
6742: CondRelLevel = NUMBER .
6743: CondOnAscend ='First' / 'Last' /
6744: 'Referred' /
6745: [ 'Immediately' ] 'Within' [ NumParent ]
6746: ElemID [ ExtStruct ] /
6747: 'Attributes' /
6748: AttrID [ RelatAttr ] /
6749: 'Presentation' /
1.34 cvs 6750: PresRule .
1.1 cvs 6751: NumParent = [ GreaterLess ] NParent .
1.30 cvs 6752: GreaterLess = '>' / '<' .
1.1 cvs 6753: NParent = NUMBER.
6754: ExtStruct = '(' ElemID ')' .
6755: Alphabet = NAME .
6756: RelatAttr ='=' Value /
1.30 cvs 6757: '>' [ '-' ] Minimum /
1.1 cvs 6758: '<' [ '-' ] Maximum /
6759: 'IN' '[' [ '-' ] MinInterval '..'
6760: [ '-' ] MaxInterval ']' .
6761: Value = [ '-' ] IntegerVal / TextVal / AttrValue .
6762: Minimum = NUMBER .
6763: Maximum = NUMBER .
6764: MinInterval = NUMBER .
6765: MaxInterval = NUMBER .
6766: IntegerVal = NUMBER .
6767: TextVal = STRING .
1.18 cvs 6768: AttrValue = NAME .</pre>
1.30 cvs 6769:
1.18 cvs 6770: <blockquote class="example">
1.30 cvs 6771: <p><strong>Example:</strong></p>
6772:
6773: <p>Suppose that after each element of type Section_Title it is useful to
6774: produce the text <tt>\label{SectX}</tt> where <tt>X</tt> represents the
6775: section number, but only if the section is designated by one or more
6776: references in the document. The following conditional rule produces this
6777: effect:</p>
6778: <pre>RULES
1.1 cvs 6779: Section_Title :
6780: IF Referred
1.18 cvs 6781: Create ('\label{Sect' Value(UniqueSectNum) '}\12') After;</pre>
1.30 cvs 6782:
6783: <p>(the declaration of the <a href="#sectc5224"><tt>UniqueSectNum</tt>
6784: counter</a> is given above). The string <tt>\12</tt> represents a line
6785: break.</p>
1.18 cvs 6786: </blockquote>
1.30 cvs 6787:
1.18 cvs 6788: <blockquote class="example">
1.30 cvs 6789: <p><strong>Example:</strong></p>
6790:
6791: <p>Suppose that for elements of the Elmnt type it would be useful to produce
6792: a character indicating the value of the numeric attribute Level associated
6793: with the element: an ``A'' for all values of Level less than 3, a ``B'' for
6794: values between 3 and 10 and a ``C'' for values greater than 10. This can be
6795: achieved by writing the following rules for the Elmnt type:</p>
6796: <pre>RULES
1.1 cvs 6797: Elmnt :
6798: BEGIN
6799: IF Level < 3
6800: Create 'A';
6801: IF Level IN [3..10]
6802: Create 'B';
1.30 cvs 6803: IF Level > 10
1.1 cvs 6804: Create 'C';
1.18 cvs 6805: END;</pre>
6806: </blockquote>
6807: </div>
6808: </div>
1.1 cvs 6809:
1.18 cvs 6810: <div class="subsection">
1.30 cvs 6811: <h3><a name="sectc529">Translation rules</a></h3>
1.1 cvs 6812:
1.30 cvs 6813: <p>Fifteen types of translation rules can be associated with element types and
1.18 cvs 6814: attribute values. They are the <tt>Create</tt>, <tt>Write</tt>,
6815: <tt>Read</tt>, <tt>Include</tt>, <tt>Get</tt>, <tt>Copy</tt>, <tt>Use</tt>,
1.31 cvs 6816: <tt>Remove</tt>, <tt>Ignore</tt>, <tt>NoTranslation</tt>,
6817: <tt>NoLineBreak</tt>, <tt>ChangeMainFile</tt>, <tt>RemoveFile</tt>,
6818: <tt>Set</tt>, <tt>Add</tt>, <tt>Indent</tt>, rules. Each rule has its own
6819: syntax, although they are all based on very similar models.</p>
1.18 cvs 6820: <pre> SimpleRule = 'Create' [ 'IN' VarID ] Object
1.1 cvs 6821: [ Position ] ';' /
6822: 'Write' Object [ Position ] ';' /
6823: 'Read' BufferID [ Position ] ';' /
6824: 'Include' File [ Position ] ';' /
6825: 'Get' [ RelPosition ] ElemID
6826: [ ExtStruct ]
6827: [ Position ] ';' /
6828: 'Copy' [ RelPosition ] ElemID
6829: [ ExtStruct ]
6830: [ Position ] ';' /
6831: 'Use' TrSchema [ 'For' ElemID ] ';' /
6832: 'Remove' ';' /
1.31 cvs 6833: 'Ignore' ';' /
1.1 cvs 6834: 'NoTranslation' ';' /
6835: 'NoLineBreak' ';' /
6836: 'ChangeMainFile' VarID [ Position ] ';' /
1.14 cvs 6837: 'RemoveFile' VarID [ Position ] ';' /
1.10 cvs 6838: 'Set' CounterID InitValue [ Position ] ';' /
6839: 'Add' CounterID Increment [ Position ] ';' /
1.25 cvs 6840: 'Indent' [ 'IN' VarID ] Indent [ Position ] ';' .</pre>
1.18 cvs 6841: </div>
6842:
6843: <div class="subsection">
1.30 cvs 6844: <h3><a name="sectc5210">The <tt>Create</tt> rule</a></h3>
1.18 cvs 6845:
1.30 cvs 6846: <p>The most frequently used rule is undoubtedly the <tt>Create</tt> rule,
6847: which generates fixed or variable text (called an <em>object</em>) in the
6848: output file. The generated text can be made to appear either before or after
6849: the content of the element to which the rule applies. The rule begins with the
1.18 cvs 6850: <tt>Create</tt> keyword, followed by a specifier for the object and a keyword
6851: (<tt>Before</tt> or <tt>After</tt>) indicating the position of the generated
6852: text (<a href="#sectc5222">before or after</a> the element's content). If the
1.1 cvs 6853: position is not indicated, the object will be generated before the element's
6854: content. This rule, like all translation rules, is terminated by a
1.18 cvs 6855: semicolon.</p>
1.30 cvs 6856:
6857: <p>The <tt>Create</tt> keyword can be followed by the <tt>IN</tt> keyword and
6858: by the name of a variable. This means that the text generated by the rule
6859: must not be written in the main output file, but in the file whose name is
1.18 cvs 6860: specified by the variable.</p>
1.30 cvs 6861:
6862: <p>This allows the translation program to generate text in different files
6863: during the same run. These files do not need to be explicitely declared or
6864: opened. They do not need to be closed either, but if they contain temporary
6865: data, they can be removed (see the <a href="#sectc5220a"><tt>RemoveFile</tt>
6866: rule</a>). As soon as the translation program executes a <tt>Create</tt> rule
6867: for a file that is not yet open, it opens the file. These files are closed
6868: when the translation is finished.</p>
1.18 cvs 6869: <pre> 'Create' [ 'IN' VarID ] Object
1.1 cvs 6870: [ Position ] ';'
6871: Object = ConstID / CharString /
6872: BufferID /
6873: VarID /
1.30 cvs 6874: '(' Function < Function > ')' /
1.21 cvs 6875: [ 'Translated' ] AttrID /
1.1 cvs 6876: 'Value' /
6877: 'Content' /
6878: 'Attributes' /
6879: 'Presentation' /
6880: 'RefId' /
6881: 'PairId' /
6882: 'FileDir' /
6883: 'FileName' /
6884: 'Extension' /
6885: 'DocumentName' /
6886: 'DocumentDir' /
6887: [ 'Referred' ] ReferredObject .
6888: Position ='After' / 'Before' .
6889:
6890: ReferredObject = VarID /
6891: ElemID [ ExtStruct ] /
6892: 'RefId' /
6893: 'DocumentName' /
1.18 cvs 6894: 'DocumentDir' .</pre>
1.30 cvs 6895:
6896: <p>The object to be generated can be:</p>
1.18 cvs 6897: <ul>
1.30 cvs 6898: <li>a constant string, specified by its name if it is declared in the
6899: schema's <tt>CONST</tt> section, or given directly as a value between
6900: apostrophes;</li>
6901: <li>the contents of a buffer, designated by the name of the buffer;</li>
6902: <li>a variable, designated by its name if it is declared in the translation
6903: schema's <tt>VAR</tt> section, or given directly between parentheses. The
6904: text generated is the value of that variable evaluated for the element to
6905: which the rule applies.</li>
6906: <li>the value of an attribute, if the element being translated has this
6907: attribute. The attribute is specified by its name. If it's a text
6908: attribute, it can be preceded by the <code>Translated</code> keyword,
6909: which causes the attribute value to be recoded using the text translation
6910: table defined by section <code><a
6911: href="#sectc5225">TEXTTRANSLATE</a></code>;</li>
6912: <li>the value of a specific presentation rule. This object can only be
6913: generated if the translation rule is for a <a href="#prestransl">specific
6914: presentation rule</a>. It is specified by the <tt>Value</tt>
6915: keyword;</li>
6916: <li>the element's content. That is, the content of the leaves of the
6917: subtree of the translated element. This is specified by the
6918: <tt>Content</tt> keyword;</li>
6919: <li>the translation of all attributes of the element (which is primarily
6920: used to apply the attribute translation rules <a
6921: href="#sectc5222">before</a> those of the element type). This is
6922: specified by the <tt>Attributes</tt> keyword.</li>
6923: <li>the translation of all of the element's specific presentation rules
6924: (which is primarily used to apply the translation rules for the specific
6925: presentation rules <a href="#sectc5222">before</a> those of the element or
6926: its attributes). This option is specified by the <tt>Presentation</tt>
6927: keyword;</li>
6928: <li>The value of the reference's identifier.<br>
6929: Thot associates a unique identifier with each element in a document. This
6930: identifier (called <em>reference's identifier</em> or <em>label</em>) is a
6931: character string containing the letter `L' followed by digits. Thot uses
6932: it in references for identifying the referred element.<br>
6933: The <tt>RefId</tt> keyword produces the reference's identifier of the
6934: element to which the translation rule is applied, or the reference's
6935: identifier of its first ancestor that is referred by a reference or that
6936: can be referred by a reference.</li>
6937: <li>the value of a mark pair's unique identifier. This may only be used for
6938: <a href="#sectd3285">mark pairs</a> and is indicated by the
6939: <tt>PairId</tt> keyword.</li>
6940: <li>the directory containing the file being generated (this string includes
6941: an ending '/', if it is not empty). This is indicated by the
6942: <tt>FileDir</tt> keyword.</li>
6943: <li>the name of the file being generated (only the name, without the
6944: directory and without the extension). This is indicated by the
6945: <tt>FileName</tt> keyword.</li>
6946: <li>the extension of the file being generated (this string starts with a
6947: dot, if it is not empty). This is indicated by the <tt>Extension</tt>
6948: keyword.</li>
6949: <li>the name of the document being translated. This is indicated by the
6950: <tt>DocumentName</tt> keyword.</li>
6951: <li>the directory containing the document being translated. This is
6952: indicated by the <tt>DocumentDir</tt> keyword.</li>
1.18 cvs 6953: </ul>
1.30 cvs 6954:
6955: <p>When the rule applies to a reference (an element or an attribute defined as
6956: a reference in the structure schema), it can generate a text related to the
1.21 cvs 6957: element referred by that reference. The rule name is then followed by the
1.18 cvs 6958: <tt>Referred</tt> keyword and a specification of the object to be generated
6959: for the referred element. This specification can be:</p>
6960: <ul>
1.30 cvs 6961: <li>the name of a variable. The rule generates the value of that variable,
6962: computed for the referred element.</li>
6963: <li>an element type. The rule generates the translation of the element of
6964: that type, which is in the subtree of the referred element. If this
6965: element is not defined in the structure schema which corresponds to the
6966: translation schema (that is, an object defined in another schema), the
6967: element's type name must be followed by the name of its structure schema
6968: between parentheses.</li>
6969: <li>the <tt>RefId</tt> keyword. The rule generates the reference's
6970: identifier of the referred element.</li>
6971: <li>the <tt>DocumentName</tt> keyword. The rule generates the name of the
6972: document to which the referred element belongs.</li>
6973: <li>the <tt>DocumentDir</tt> keyword. The rule generates the name of the
6974: directory that contains the document of the referred element.</li>
1.18 cvs 6975: </ul>
6976: </div>
1.1 cvs 6977:
1.18 cvs 6978: <div class="subsection">
1.30 cvs 6979: <h3><a name="sectc5211">The <tt>Write</tt> rule</a></h3>
1.1 cvs 6980:
1.30 cvs 6981: <p>The <tt>Write</tt> has the same syntax as the <tt>Create</tt> rule. It
6982: also produces the same effect, but the generated text is displayed on the
6983: user's terminal during the translation of the document, instead of being
6984: produced in the translated document. This is useful for helping the user keep
6985: track of the progress of the translation and for prompting the user on the
6986: terminal for input required by the <tt>Read</tt> rule.</p>
1.18 cvs 6987: <pre> 'Write' Object [ Position ] ';'</pre>
1.30 cvs 6988:
6989: <p>Notice: if the translator is launched by the editor (by the ``Save as''
1.18 cvs 6990: command), messages produced by the <tt>Write</tt> rule are not displayed.</p>
1.30 cvs 6991:
1.18 cvs 6992: <blockquote class="example">
1.30 cvs 6993: <p><strong>Example:</strong></p>
6994:
6995: <p>To make the translator display the number of each section being
6996: translated on the user's terminal, the following rule is specified for the
6997: <tt>Section</tt> element type:</p>
6998: <pre>Section : BEGIN
1.1 cvs 6999: Write VarSection;
7000: ...
1.18 cvs 7001: END;</pre>
1.30 cvs 7002:
7003: <p>(see <a href="#varsectexample">above</a> for the definition of the
7004: <tt>VarSection</tt> variable).</p>
7005:
7006: <p>To display text on the terminal before issuing a read operation with the
7007: <tt>Read</tt> rule, the following rule is used:</p>
7008: <pre>BEGIN
1.1 cvs 7009: Write 'Enter the name of the destination: ';
7010: ...
1.18 cvs 7011: END;</pre>
7012: </blockquote>
7013: </div>
7014:
7015: <div class="subsection">
1.30 cvs 7016: <h3><a name="sectc5212">The <tt>Read</tt> rule</a></h3>
1.18 cvs 7017:
1.30 cvs 7018: <p>The <tt>Read</tt> rule reads text from the terminal during the translation
7019: of the document and saves the text read in one of the buffers declared in the
1.18 cvs 7020: <tt>BUFFERS</tt> section of the schema. The buffer to be used is indicated by
7021: its name, after the <tt>READ</tt> keyword. This name can be followed, as in
7022: the <tt>Create</tt> and <tt>Write</tt> rules, by a keyword indicating if the
7023: read operation must be performed <tt>Before</tt> or <tt>After</tt> the
1.1 cvs 7024: translation of the element's content. If this keyword is absent, the read
7025: operation is done beforehand. The text is read into the buffer and remains
1.5 cvs 7026: there until a rule using the same buffer - possibly the same rule - is
1.18 cvs 7027: applied.</p>
7028: <pre> 'Read' BufferID [ Position ] ';'</pre>
1.30 cvs 7029:
1.18 cvs 7030: <blockquote class="example">
1.30 cvs 7031: <p><strong>Example:</strong></p>
7032:
7033: <p>The following set of rules tells the user that the translator is waiting
7034: for the entry of some text, reads this text into a buffer and copies the
7035: text into the translated document.</p>
7036: <pre>BEGIN
1.1 cvs 7037: Write 'Enter the name of the destination: ';
7038: Read DestName;
7039: Create DestName;
7040: ...
1.18 cvs 7041: END;</pre>
1.30 cvs 7042:
7043: <p>(see <a href="#destname">above</a> the definition of
7044: <tt>DestName</tt>).</p>
1.18 cvs 7045: </blockquote>
7046: </div>
7047:
7048: <div class="subsection">
1.30 cvs 7049: <h3><a name="sectc5213">The <tt>Include</tt> rule</a></h3>
1.18 cvs 7050:
1.30 cvs 7051: <p>The <tt>Include</tt> rule, like the <tt>Create</tt> rule, is used to
7052: produce text in the translated document. It inserts constant text which is
7053: not defined in the translation schema, but is instead taken from a file. The
1.18 cvs 7054: file's name is specified after the <tt>Include</tt> keyword, either directly
1.1 cvs 7055: as a character string between apostrophes or as the name of one of the buffers
1.18 cvs 7056: declared in the <tt>BUFFERS</tt> section of the schema. In the latter case,
1.1 cvs 7057: the buffer is assumed to contain the file's name. This can be used when the
7058: included file's name is known only at the moment of translation. This only
1.18 cvs 7059: requires that the <tt>Include</tt> rule is preceded by a <tt>Read</tt> rule
7060: which puts the name of the file desired by the user into the buffer.</p>
1.30 cvs 7061:
7062: <p>Like the other rules, it is possible to specify whether the inclusion will
1.1 cvs 7063: occur before or after the element's content, with the default being before.
7064: The file inclusion is only done at the moment of translation, not during the
7065: compilation of the translation schema. Thus, the file to be included need not
7066: exist during the compilation, but it must be accessible at the time of
7067: translation. Its contents can also be modified between two translations, thus
7068: producing different results, even if neither the document or the translation
1.18 cvs 7069: schema are modified.</p>
1.30 cvs 7070:
7071: <p>During translation, the file to be included is searched for along the
7072: schema directory path (indicated by the environment variable
7073: <tt>THOTSCH</tt>). The file name is normally only composed of a simple name,
7074: without specification of a complete file path. However, if the filename
7075: starts with a '/', it is considered as an absolute path.</p>
1.18 cvs 7076: <pre> 'Include' File [ Position ] ';'
1.6 cvs 7077: File = FileName / BufferID .
1.18 cvs 7078: FileName = STRING .</pre>
1.30 cvs 7079:
1.18 cvs 7080: <blockquote class="example">
1.30 cvs 7081: <p><strong>Example:</strong></p>
7082:
7083: <p>Suppose that it is desirable to print documents of the Article class with
7084: a formatter which requires a number of declarations and definitions at the
7085: beginning of the file. The <tt>Include</tt>rule can be used to achieve
7086: this. All the declarations and definitions a replaced in a file called
7087: <tt>DeclarArt</tt> and then the <tt>Article</tt> element type is given the
7088: following rule:</p>
7089: <pre>Article : BEGIN
1.1 cvs 7090: Include 'DeclarArt' Before;
7091: ...
1.18 cvs 7092: END;</pre>
7093: </blockquote>
7094: </div>
7095:
7096: <div class="subsection">
1.30 cvs 7097: <h3><a name="sectc5214">The <tt>Get</tt> rule</a></h3>
1.18 cvs 7098:
1.30 cvs 7099: <p>The <tt>Get</tt> rule is used to change the order in which the elements
7100: appear in the translated document. More precisely, it produces the
7101: translation of a specified element before or after the translation of the
7102: content of the element to which the rule applies. The <tt>Before</tt> and
7103: <tt>After</tt> keywords are placed at the end of the rule to specify whether
7104: the operation should be performed before or after translation of the rule's
7105: element (the default is before). The type of the element to be moved must be
7106: specified after the <tt>Get</tt> keyword, optionally preceded by a keyword
7107: indicating where the element will be found in the logical structure of the
7108: document:</p>
1.18 cvs 7109: <dl>
1.30 cvs 7110: <dt><tt>Included</tt></dt>
7111: <dd>The element to be moved is the first element of the indicated type
7112: which is found inside the element to which the rule applies.</dd>
7113: <dt><tt>Referred</tt></dt>
7114: <dd>This keyword can only be used if the rule applies to a reference
7115: element. The element to be moved is either the element designated by the
7116: reference (if that element is of the specified type), or the first
7117: element of the desired type contained within the element designated by
7118: the reference.</dd>
7119: <dt>no keyword</dt>
7120: <dd>If the element to be moved is an associated element, defined in the <a
7121: href="#sectc314"><tt>ASSOC</tt> section</a> of the structure schema, all
7122: associated elements of this type which have not been translated yet are
7123: then translated. Certain elements may in fact have already been
7124: translated by a <tt>Get Referred</tt> rule.
7125: <p>If the element to be moved is not an associated element, the
7126: translator takes the first element of the indicated type from among the
7127: siblings of the rule's element. This is primarily used to change the
7128: order of the components of an aggregate.</p>
7129: </dd>
1.18 cvs 7130: </dl>
1.30 cvs 7131:
7132: <p>If the element to be moved is defined in a structure schema which is not
7133: the one which corresponds to the translation schema (in the case of an
7134: included object with a different schema), the type name of this element must
7135: be followed, between parentheses, by the name of the structure schema which
1.18 cvs 7136: defines it.</p>
7137: <pre> 'Get' [ RelPosition ] ElemID
1.6 cvs 7138: [ ExtStruct ]
7139: [ Position ] ';' /
7140: RelPosition = 'Included' / 'Referred' .
1.18 cvs 7141: ExtStruct = '(' ElemID ')' .</pre>
1.30 cvs 7142:
7143: <p>The <tt>Get</tt> rule has no effect if the element which it is supposed to
1.1 cvs 7144: move has already been translated. Thus, the element will not be duplicated.
7145: It is generally best to associate the rule with the first element which will
7146: be encountered by the translator in its traversal of the document. Suppose an
1.18 cvs 7147: aggregate has two elements <tt>A</tt> and <tt>B</tt>, with <tt>A</tt>
1.1 cvs 7148: appearing first in the logical structure. To permute these two elements, a
1.18 cvs 7149: <tt>Get B before</tt> rule should be associated with the <tt>A</tt> element
7150: type, not the inverse. Similarly, a rule of the form <tt>Get Included X
7151: After</tt>, even though syntactically correct, makes no sense since, by the
1.1 cvs 7152: time it will be applied, after the translation of the contents of the element
1.18 cvs 7153: to which it is attached, the <tt>X</tt> element will already have been
7154: translated.</p>
1.30 cvs 7155:
7156: <p>The <tt>Get</tt> rule is the only way to obtain the translation of the
1.1 cvs 7157: associated elements. In fact, the translator only traverses the primary tree
7158: of the document and thus does not translate the associated elements, except
1.18 cvs 7159: when the translation is explicitly required by a <tt>Get Referred Type</tt> or
7160: <tt>Get Type</tt> rule where <tt>Type</tt> is an associated element type.</p>
1.30 cvs 7161:
1.18 cvs 7162: <blockquote class="example">
1.30 cvs 7163: <p><strong>Example:</strong></p>
7164:
7165: <p>The structure schema defined figures as associated element which are
7166: composed of some content and a caption. Moreover, it is possible to make
7167: references to figures, using elements of the <tt>RefFigure</tt> type:</p>
7168: <pre> ...
1.1 cvs 7169: RefFigure = REFERENCE(Figure);
7170: ASSOC
1.6 cvs 7171: Figure = BEGIN
7172: Content = NATURE;
7173: Caption = Text;
7174: END;
1.18 cvs 7175: ...</pre>
1.30 cvs 7176:
7177: <p>Suppose it would be useful to make a figure appear in the translated
7178: document at the place in the text where the first reference to the figure is
7179: made. If some figures are not referenced, then they would appear at the end
7180: of the document. Also, each figure's caption should appear before the
7181: content. The following rules in the translation schema will produce this
7182: result:</p>
7183: <pre>Article : BEGIN
1.1 cvs 7184: ...
7185: Get Figures After;
7186: END;
7187: RefFigure : BEGIN
7188: If FirstRef Get Referred Figure;
7189: ...
7190: END;
7191: Content : BEGIN
7192: Get Caption Before;
7193: ...
1.18 cvs 7194: END;</pre>
7195: </blockquote>
7196: </div>
7197:
7198: <div class="subsection">
1.30 cvs 7199: <h3><a name="sectc5215">The <tt>Copy</tt> rule</a></h3>
1.18 cvs 7200:
1.30 cvs 7201: <p>Like the <tt>Get</tt> rule, the <tt>Copy</tt> rule generates the
7202: translation of a specified element, but it acts even if the element has
7203: already been translated and it allows to copy it or to translate it later.
7204: Both rules have the same syntax.</p>
1.18 cvs 7205: <pre> 'Copy' [ RelPosition ] ElemID
7206: [ ExtStruct ] [ Position ] ';'</pre>
7207: </div>
7208:
7209: <div class="subsection">
1.30 cvs 7210: <h3><a name="sectc5216">The <tt>Use</tt> rule</a></h3>
1.18 cvs 7211:
1.30 cvs 7212: <p>The <tt>Use</tt> rule specifies the translation schema to be applied to
1.1 cvs 7213: objects of a certain class that are part of the document. This rule only
7214: appears in the rules for the root element of the document (the first type
1.18 cvs 7215: defined after the <tt>STRUCT</tt> keyword in the structure schema) or the
1.1 cvs 7216: rules of an element defined by an external structure (by another structure
1.18 cvs 7217: schema). Also, the <tt>Use</tt> rule cannot be conditional.</p>
1.30 cvs 7218:
7219: <p>If the rule is applied to an element defined by an external structure, the
1.18 cvs 7220: <tt>Use</tt> keyword is simply followed by the name of the translation schema
1.1 cvs 7221: to be used for element constructed according to that external structure. If
7222: the rule is applied to the document's root element, it is formed by the
1.18 cvs 7223: <tt>Use</tt> keyword followed by the translation schema's name, the
7224: <tt>For</tt> keyword and the name of the external structure to which the
7225: indicated translation schema should be applied.</p>
7226: <pre> 'Use' TrSchema [ 'For' ElemID ] ';'
7227: TrSchema = NAME .</pre>
1.30 cvs 7228:
7229: <p>If no <tt>Use</tt> rule defines the translation schema to be used for an
1.1 cvs 7230: external structure which appears in a document, the translator asks the user,
7231: during the translation process, which schema should be used. Thus, it is not
1.18 cvs 7232: necessary to give the translation schema a <tt>Use</tt> rule for every
1.1 cvs 7233: external structure used, especially when the choice of translation schemas is
1.18 cvs 7234: to be left to the user.</p>
1.30 cvs 7235:
7236: <p>Notice: if the translator is launched by the editor (by the ``Save as''
1.18 cvs 7237: command), prompts are not displayed.</p>
1.30 cvs 7238:
1.18 cvs 7239: <blockquote class="example">
1.30 cvs 7240: <p><strong>Example:</strong></p>
7241:
7242: <p>The <tt>Article</tt> structure schema uses the <tt>Formula</tt> external
7243: structure, defined by another structure schema, for mathematical
7244: formulas:</p>
7245: <pre>STRUCTURE Article;
1.1 cvs 7246: ...
7247: STRUCT
7248: Article = ...
7249: ...
7250: Formula_in_text = Formula;
7251: Isolated_formula = Formula;
7252: ...
1.18 cvs 7253: END</pre>
1.30 cvs 7254:
7255: <p>Suppose that it would be useful to use the <tt>FormulaT</tt> translation
7256: schema for the formulas of an article. This can be expressed in two
7257: different ways in the <tt>Article</tt> class translation schema, using the
7258: rules:</p>
7259: <pre>RULES
1.1 cvs 7260: Article :
1.18 cvs 7261: Use FormulaT for Formula;</pre>
1.30 cvs 7262:
7263: <p>or:</p>
7264: <pre>RULES
1.1 cvs 7265: ...
7266: Formula :
1.18 cvs 7267: Use FormulaT;</pre>
7268: </blockquote>
7269: </div>
7270:
7271: <div class="subsection">
1.30 cvs 7272: <h3><a name="sectc5217">The <tt>Remove</tt> rule</a></h3>
1.18 cvs 7273:
1.30 cvs 7274: <p>The <tt>Remove</tt> rule indicates that nothing should be generated, in the
1.1 cvs 7275: translated document, for the content of the element to which the rule applies.
7276: The content of that element is simply ignored by the translator. This does
7277: not prevent the generation of text for the element itself, using the
1.18 cvs 7278: <tt>Create</tt> or <tt>Include</tt> rules, for example.</p>
1.30 cvs 7279:
7280: <p>The <tt>Remove</tt> rule is simply written with the <tt>Remove</tt>
7281: keyword. It is terminated, like all rules, by a semicolon.</p>
1.18 cvs 7282: <pre> 'Remove' ';'</pre>
7283: </div>
7284:
7285: <div class="subsection">
1.31 cvs 7286: <h3><a name="sectc5217a">The <tt>Ignore</tt> rule</a></h3>
7287:
7288: <p>The <tt>Ignore</tt> rule indicates that nothing should be generated, in the
7289: translated document, for the element to which the rule applies. The whole
1.32 cvs 7290: element is simply ignored by the translator.</p>
1.31 cvs 7291:
7292: <p>The <tt>Ignore</tt> rule is simply written with the <tt>Ignore</tt>
7293: keyword. It is terminated, like all rules, by a semicolon.</p>
7294: <pre> 'Ignore' ';'</pre>
7295: </div>
7296:
7297: <div class="subsection">
1.30 cvs 7298: <h3><a name="sectc5218">The <tt>NoTranslation</tt> rule</a></h3>
1.18 cvs 7299:
1.30 cvs 7300: <p>The <tt>NoTranslation</tt> rule indicates to the translator that it must
7301: not translate the content of the leaves of the element to which it applies. In
1.18 cvs 7302: contrast to the <tt>Remove</tt> rule, it does not suppress the content of the
1.1 cvs 7303: element, but it inhibits the translation of character strings, symbols, and
7304: graphical elements contained in the element. These are retrieved so that
1.18 cvs 7305: after the translation of the document, the rules of the <a
7306: href="#sectc5225"><tt>TEXTTRANSLATE</tt>, <tt>SYMBTRANSLATE</tt> and
7307: <tt>GRAPHTRANSLATE</tt> sections</a> will not be applied to them.</p>
1.30 cvs 7308:
7309: <p>The <tt>NoTranslation</tt> rule is written with the <tt>NoTranslation</tt>
1.18 cvs 7310: keyword followed by a semicolon.</p>
7311: <pre> 'NoTranslation' ';'</pre>
7312: </div>
7313:
7314: <div class="subsection">
1.30 cvs 7315: <h3><a name="sectc5219">The <tt>NoLineBreak</tt> rule</a></h3>
1.18 cvs 7316:
1.30 cvs 7317: <p>The <tt>NoLineBreak</tt> rule indicates to the translator that it must not
1.1 cvs 7318: generate additional line breaks in the output produced for the element to
1.18 cvs 7319: which it applies. This is as if it was an <a href="#sectc522">instruction
7320: <tt>LINELENGTH 0;</tt></a> at the beginning of the translation schema, but
7321: only for the current element.</p>
1.30 cvs 7322:
7323: <p>The <tt>NoLineBreak</tt> rule is written with the <tt>NoLineBreak</tt>
7324: keyword followed by a semicolon.</p>
1.18 cvs 7325: <pre> 'NoLineBreak' ';'</pre>
7326: </div>
1.1 cvs 7327:
1.18 cvs 7328: <div class="subsection">
1.30 cvs 7329: <h3><a name="sectc5220">The <tt>ChangeMainFile</tt> rule</a></h3>
1.1 cvs 7330:
1.30 cvs 7331: <p>When the translation program starts, it opens a main output file, whose
7332: name is given as a parameter of the translator. All <a
1.18 cvs 7333: href="#sectc5210"><tt>Create</tt> rules</a> without explicit indication of the
7334: output file write sequentially in this file. When a <tt>ChangeMainFile</tt>
7335: rule is executed, the main output file is closed and it is replaced by a new
7336: one, whose name is specified in the <tt>ChangeMainFile</tt> rule. The
7337: <tt>Create</tt> rules without indication of the output file that are then
7338: executed write in this new file. Several <tt>ChangeMainFile</tt> rules can be
7339: executed during the same translation, for dividing the main output into
7340: several files.</p>
1.30 cvs 7341:
7342: <p>This rule is written with the <tt>ChangeMainFile</tt> keyword followed by
7343: the name of a variable that specifies the name of the new main file. The
7344: keyword <tt>Before</tt> or <tt>After</tt> can be placed at the end of the rule
7345: to specify whether the operation should be performed before or after
7346: translation of the rule's element (the default is before). This rule, like all
7347: translation rules, is terminated by a semicolon.</p>
1.18 cvs 7348: <pre> 'ChangeMainFile' VarID [ Position ] ';'</pre>
1.30 cvs 7349:
1.18 cvs 7350: <blockquote class="example">
1.30 cvs 7351: <p><strong>Example:</strong></p>
7352:
7353: <p>To generate the translation of each section in a different file, the
7354: following rule can be associated with type <tt>Section</tt>. That rule uses
7355: the <a href="#varoutputfile"><tt>VarOutpuFile</tt> variable</a> defined
7356: above.</p>
7357: <pre> Section:
1.18 cvs 7358: ChangeMainFile VarOutpuFile Before;</pre>
1.30 cvs 7359:
7360: <p>If <tt>output.txt</tt> is the name of the output file specified when
7361: starting the translation program, translated sections are written in files
7362: <tt>output1.txt</tt>, <tt>output2.txt</tt>, etc.</p>
1.18 cvs 7363: </blockquote>
7364: </div>
1.1 cvs 7365:
1.18 cvs 7366: <div class="subsection">
1.30 cvs 7367: <h3><a name="sectc5220a">The <tt>RemoveFile</tt> rule</a></h3>
1.14 cvs 7368:
1.30 cvs 7369: <p>Files may be used for storing temporary data that are no longer needed when
1.18 cvs 7370: the translation of a document is complete. These files may be removed by the
7371: <tt>RemoveFile</tt> rule.</p>
1.30 cvs 7372:
7373: <p>This rule is written with the <tt>RemoveFile</tt> keyword followed by the
7374: name of a variable that specifies the name of the file to be removed. The
7375: keyword <tt>Before</tt> or <tt>After</tt> can be placed at the end of the rule
7376: to specify whether the operation should be performed before or after
7377: translation of the rule's element (the default is before). This rule, like
7378: all translation rules, is terminated by a semicolon.</p>
1.18 cvs 7379: <pre> 'RemoveFile' VarID [ Position ] ';'</pre>
7380: </div>
7381:
7382: <div class="subsection">
1.30 cvs 7383: <h3><a name="sectc5221">The <tt>Set</tt> and <tt>Add</tt> rules</a></h3>
1.18 cvs 7384:
1.30 cvs 7385: <p>The <tt>Set</tt> and <tt>Add</tt> rules are used for modifying the value of
1.18 cvs 7386: counters that have no <a href="#sectc524">counting function</a>. Only this
7387: type of counter can be used in the <tt>Set</tt> and <tt>Add</tt> rules.</p>
1.30 cvs 7388:
7389: <p>Both rules have the same syntax: after the keyword <tt>Set</tt> or
1.18 cvs 7390: <tt>Add</tt> appear the counter name and the value to assign to the counter
7391: (<tt>Set</tt> rule) or the value to be added to the counter (<tt>Add</tt>
7392: rule). The keyword <tt>Before</tt> or <tt>After</tt> can follow that value to
1.1 cvs 7393: indicate when the rule must be applied: before or after the element's content
1.18 cvs 7394: is translated. By default, <tt>Before</tt> is assumed. A semicolon terminates
7395: the rule.</p>
7396: <pre> 'Set' CounterID InitValue [ Position ] ';' /
7397: 'Add' CounterID Increment [ Position ] ';'</pre>
7398: </div>
7399:
7400: <div class="subsection">
1.30 cvs 7401: <h3><a name="sectc5221a">The <tt>Indent</tt> rule</a></h3>
1.18 cvs 7402:
1.30 cvs 7403: <p>The <tt>Indent</tt> rule is used to modify the value of text indentation in
1.18 cvs 7404: the output files.</p>
1.30 cvs 7405:
7406: <p>Each time the translator creates a new line in an output file, it generates
7407: a variable number of space characters at the beginning of the new line. By
1.25 cvs 7408: default, the number of these characters (the indentation value) is 0. It can
7409: be changed with the <tt>Indent</tt> rule.</p>
1.30 cvs 7410:
7411: <p>In its simple form, the rule begins with the <tt>Indent</tt> keyword,
1.25 cvs 7412: followed by the indentation sign (optional) and value and a keyword
1.30 cvs 7413: <tt>Before</tt> or <tt>After</tt> indicating that the indentation should be
7414: changed <a href="#sectc5222">before or after</a> the element's content is
7415: generated. If the position is not indicated, the indentation is changed
1.25 cvs 7416: before the element's content is generated. This rule, like all translation
7417: rules, is terminated by a semicolon.</p>
1.30 cvs 7418:
7419: <p>The indentation value is indicated by an integer, which is the number of
7420: space characters to be generated at the beginning of each new line. A sign
1.18 cvs 7421: (<tt>+</tt> or <tt>-</tt>) can appear before the integer to indicate that the
7422: value is relative: the current value of indentation is incremented (if sign is
7423: <tt>+</tt>) or decremented (if sign is <tt>-</tt>) by the specified value.</p>
1.30 cvs 7424:
7425: <p>Keyword <tt>Suspend</tt> or <tt>Resume</tt> can appear instead of the
1.25 cvs 7426: (possibly signed) identation value. <tt>Suspend</tt> means that the new
1.30 cvs 7427: indentation value to be used is zero until another <tt>Indent</tt> rule is
7428: executed and changes the indentation value. <tt>Resume</tt> means that the
7429: indentation value that was used before the last <tt>Indent Suspend</tt> was
7430: executed becomes the new value. Only one <tt>Suspend</tt> can be used before
7431: a <tt>Resume</tt>; <tt>Supend</tt>-<tt>Resume</tt> pairs can not be
7432: nested.</p>
7433:
7434: <p>Like the <a href="#sectc5210"><tt>Create</tt> rule</a>, the <tt>Indent</tt>
1.18 cvs 7435: keyword can be followed by the <tt>IN</tt> keyword and by the name of a <a
7436: href="#sectc526">variable</a>. This means that the rule must not change
1.10 cvs 7437: indentation in the main output file, but in the file whose name is specified
7438: by the variable (by default, indentation is changed in the main output
1.18 cvs 7439: file).</p>
1.25 cvs 7440: <pre> 'Indent' [ 'IN' VarID ] Indent [ Position ] ';' .
1.10 cvs 7441:
1.25 cvs 7442: Indent = 'Suspend' / 'Resume' / [ IndentSign ] IndentValue .
1.10 cvs 7443: IndentSign = '+' / '-' .
1.18 cvs 7444: IndentValue = NUMBER .</pre>
7445: </div>
1.10 cvs 7446:
1.18 cvs 7447: <div class="subsection">
1.30 cvs 7448: <h3><a name="sectc5222">Rule application order</a></h3>
1.1 cvs 7449:
1.30 cvs 7450: <p>The translator translates the elements which comprise the document in the
1.18 cvs 7451: order induced by the tree structure, except when the <tt>Get</tt> rule is used
1.1 cvs 7452: to change the order of translation. For each element, the translator first
7453: applies the rules specified for the element's type that must be applied before
1.18 cvs 7454: translation of the element's content (rules ending with the <tt>Before</tt>
1.1 cvs 7455: keyword or which have no position keyword). If several rules meet these
7456: criteria, the translator applies them in the order in where they appear in the
1.18 cvs 7457: translation schema.</p>
1.30 cvs 7458:
7459: <p>It then applies all <a href="#sectc5223">rules for the attributes</a> which
1.1 cvs 7460: the element has and which must be applied before the translation of the
1.18 cvs 7461: element's content (rules ending with the <tt>Before</tt> keyword or which have
1.1 cvs 7462: no position keyword). For one attribute value, the translator applies the
1.18 cvs 7463: rules in the order in which they are defined in the translation schema.</p>
1.30 cvs 7464:
7465: <p>The same procedure is followed with translation rules for specific
1.18 cvs 7466: presentations.</p>
1.30 cvs 7467:
1.31 cvs 7468: <p>Next, the element's content is translated, as long as a <tt>Remove</tt> or
7469: <code>Ignore</code> rule does not apply.</p>
1.30 cvs 7470:
7471: <p>In the next step, the translator applies rules for the specific
7472: presentation of the element that are to be applied after translation of the
7473: content (rules which end with the <tt>After</tt> keyword). The rules for each
7474: type of presentation rule or each value are applied in the order in which the
1.18 cvs 7475: translation appear in the schema.</p>
1.30 cvs 7476:
7477: <p>Then, the same procedure is followed for translation rules for attributes
7478: of the element.</p>
7479:
7480: <p>Finally, the translator applies rules for the element which must be applied
1.1 cvs 7481: after translation of the element's content. These rules are applied in the
7482: order that they appear in the translation schema. When the translation of an
7483: element is done, the translator procedes to translate the following
1.18 cvs 7484: element.</p>
1.30 cvs 7485:
7486: <p>This order can be changed with the <tt>Attributes</tt> and
1.18 cvs 7487: <tt>Presentation</tt> options of the <a href="#sectc5210"><tt>Create</tt>
7488: rule</a>.</p>
7489: </div>
1.1 cvs 7490:
1.18 cvs 7491: <div class="subsection">
1.30 cvs 7492: <h3><a name="sectc5223">Translation of logical attributes</a></h3>
1.1 cvs 7493:
1.30 cvs 7494: <p>After the rules for the element types, the translation schema defines rules
1.18 cvs 7495: for attribute values. This section begins with the <tt>ATTRIBUTES</tt>
1.1 cvs 7496: keyword and is composed of a sequence of rule blocks each preceded by an
1.18 cvs 7497: attribute name and an optional value or value range.</p>
1.30 cvs 7498:
7499: <p>If the attribute's name appears alone before the rule block, the rule are
1.1 cvs 7500: applied to all element which have the attribute, no matter what value the
7501: attribute has. In this case, the attribute name is followed by a colon before
1.18 cvs 7502: the beginning of the rule block.</p>
1.30 cvs 7503:
7504: <p>The attribute's name can be followed by the name of an element type between
1.1 cvs 7505: parentheses. This says, as in presentation schemas, that the rule block which
7506: follows applies not to the element which has the attribute, but to its
1.18 cvs 7507: descendants of the type indicated between the parentheses.</p>
1.30 cvs 7508:
7509: <p>If values are given after the attribute name (or after the name of the
7510: element type), the rules are applied only when the attribute has the indicated
7511: values. The same attribute can appear several times, with different values and
1.1 cvs 7512: different translation rules. Attribute values are indicated in the same way
1.18 cvs 7513: as in <a href="#sectc528">conditions</a> and are followed by a colon before
7514: the block of rules.</p>
1.30 cvs 7515:
7516: <p>The rule block associated with an attribute is either a simple rule or a
1.18 cvs 7517: sequence of rules delimited by the <tt>BEGIN</tt> and <tt>END</tt> keywords.
7518: Note that rules associated with attribute values cannot be conditional.</p>
1.30 cvs 7519:
7520: <p>Translation rules are not required for all attributes (or their values)
1.1 cvs 7521: defined in a structure schema. Only those attributes for which a particular
7522: action must be performed by the translator must have such rules. The rules
1.18 cvs 7523: that can be used are those described above, from <a
7524: href="#sectc5210"><tt>Create</tt></a> to <a
7525: href="#sectc5218"><tt>NoTranslation</tt></a>.</p>
1.30 cvs 7526: <pre> AttrSeq = TransAttr < TransAttr > .
1.1 cvs 7527: TransAttr = AttrID [ '(' ElemID ')' ]
7528: [ RelatAttr ] ':' RuleSeq .
7529: AttrID = NAME .
1.18 cvs 7530: ElemID = NAME .</pre>
1.30 cvs 7531:
1.18 cvs 7532: <blockquote class="example">
1.30 cvs 7533: <p><strong>Example:</strong></p>
7534:
7535: <p>The structure defined the ``Language'' attribute which can take the
7536: values ``French'' and ``English''. To have the French parts of the original
7537: document removed and prevent the translation of the leaves of the English
7538: parts, the following rules would be used:</p>
7539: <pre>ATTRIBUTES
1.1 cvs 7540: Language=French :
7541: Remove;
7542: Language=English :
1.18 cvs 7543: NoTranslation;</pre>
7544: </blockquote>
7545: </div>
1.1 cvs 7546:
1.18 cvs 7547: <div class="subsection">
1.30 cvs 7548: <h3><a name="sectc5224">Translation of specific presentations</a></h3>
1.1 cvs 7549:
1.30 cvs 7550: <p>After the rules for attributes, the translation schema defines rules for
7551: the specific presentation. This section begins with the <tt>PRESENTATION</tt>
1.1 cvs 7552: keyword and is composed of a sequence of translation rule blocks each preceded
7553: by a presentation rule name, optionally accompanied by a part which depends on
1.18 cvs 7554: the particular presentation rule.</p>
1.30 cvs 7555:
7556: <p>Each of these translation rule blocks is applied when the translator
7557: operates on an element which has a specific presentation rule of the type
7558: indicated at the head of the block. Depending on the type of the specific
7559: presentation rule, it is possible to specify values of the presentation rule
7560: for which the translation rule block should be applied.</p>
7561:
7562: <p>There are three categories of the presentation rules:</p>
7563: <ul>
7564: <li>rules taking numeric values: <tt>Size</tt>, <tt>Indent</tt>,
7565: <tt>LineSpacing</tt>, <tt>LineWeight</tt>,</li>
7566: <li>rules whose values are taken from a predefined list (i.e. whose type is
1.36 ! cvs 7567: an enumeration): <tt>Adjust</tt>, <tt>Hyphenate,/TT>, <tt>Style</tt>,
! 7568: <tt>Weight</tt>, <tt>Font</tt>, <tt>UnderLine</tt>, <tt>Thickness</tt>,
! 7569: <tt>LineStyle</tt>,</tt></li>
1.30 cvs 7570: <li>rules whose value is a name: <tt>FillPattern</tt>, <tt>Background</tt>,
7571: <tt>Foreground</tt>.</li>
1.18 cvs 7572: </ul>
1.30 cvs 7573:
7574: <p>For presentation rules of the first category, the values which provoke
1.1 cvs 7575: application of the translation rules are indicated in the same manner as for
1.18 cvs 7576: <a href="#relattr">numeric attributes</a>. This can be either a unique value
1.1 cvs 7577: or range of values. For a unique value, the value (an integer) is simply
7578: preceded by an equals sign. Value ranges can be specified in one of three
1.18 cvs 7579: ways:</p>
7580: <ul>
1.30 cvs 7581: <li>all values less than a given value (this value is preceded by a ``less
7582: than'' sign '<tt><</tt>'),</li>
7583: <li>all values greater than a given value (this value is preceded by a`
7584: `greater than'' sign '<tt>></tt>'),</li>
7585: <li>all values falling in an interval, bounds included. The range of values
7586: is then specified <tt>IN [</tt>Minimum<tt>..</tt>Maximum<tt>]</tt>, where
7587: Minimum and Maximum are integers.</li>
1.18 cvs 7588: </ul>
1.30 cvs 7589:
7590: <p>All numeric values can be negative, in which case the integer is preceded
7591: by a minus sign. All values must be given in typographers points.</p>
7592:
7593: <p>For presentation rules whose values are taken from a predefined list, the
1.1 cvs 7594: value which provokes application of the translation rules is simply indicated
1.18 cvs 7595: by the equals sign followed by the name of the value.</p>
1.30 cvs 7596:
7597: <p>For presentation rules whose values are names, the value which provokes the
1.1 cvs 7598: application of translation rules is simply indicated by the equals sign
7599: followed by the name of the value. The names of the fill patterns (the
1.18 cvs 7600: <tt>FillPattern</tt> rule) and of the colors (the <tt>Foreground</tt> and
7601: <tt>Background</tt> rules) used in Thot are the same as in the P language.</p>
1.30 cvs 7602: <pre> PresSeq = PresTrans < PresTrans > .
1.1 cvs 7603: PresTrans = PresRule ':' RuleSeq .
7604: PresRule = 'Size' [ PresRelation ] /
7605: 'Indent' [ PresRelation ] /
7606: 'LineSpacing' [ PresRelation ] /
7607: 'Adjust' [ '=' AdjustVal ] /
7608: 'Hyphenate' [ '=' BoolVal ] /
7609: 'Style' [ '=' StyleVal ] /
1.24 cvs 7610: 'Weight' [ '=' WeightVal ] /
1.1 cvs 7611: 'Font' [ '=' FontVal ] /
7612: 'UnderLine' [ '=' UnderLineVal ] /
7613: 'Thickness' [ '=' ThicknessVal ] /
7614: 'LineStyle' [ '=' LineStyleVal ] /
7615: 'LineWeight' [ PresRelation ] /
7616: 'FillPattern' [ '=' Pattern ] /
7617: 'Background' [ '=' Color ] /
7618: 'Foreground' [ '=' Color ] .
7619:
7620: PresRelation = '=' PresValue /
1.30 cvs 7621: '>' [ '-' ] PresMinimum /
1.1 cvs 7622: '<' [ '-' ] PresMaximum /
7623: 'IN' '[' [ '-' ] PresIntervalMin '..'
7624: [ '-' ] PresIntervalMax ']' .
1.35 cvs 7625: AdjustVal = 'Left' / 'Right' / 'VMiddle' / 'Justify' /
1.1 cvs 7626: 'LeftWithDots' .
7627: BoolVal = 'Yes' / 'No' .
1.24 cvs 7628: StyleVal = 'Roman' / 'Italics' / 'Oblique' .
7629: WeightVal = 'Normal' / 'Bold' .
1.1 cvs 7630: FontVal = 'Times' / 'Helvetica' / 'Courier' .
7631: UnderLineVal = 'NoUnderline' / 'UnderLined' /
7632: 'OverLined' / 'CrossedOut' .
7633: ThicknessVal = 'Thick' / 'Thin' .
1.6 cvs 7634: LineStyleVal = 'Solid' / 'Dashed' / 'Dotted' .
1.1 cvs 7635: Pattern = NAME .
7636: Color = NAME .
7637: PresMinimum = NUMBER .
7638: PresMaximum = NUMBER .
7639: PresIntervalMin= NUMBER .
7640: PresIntervalMax= NUMBER .
7641: PresValue = [ '-' ] PresVal .
1.18 cvs 7642: PresVal = NUMBER .</pre>
1.30 cvs 7643:
7644: <p>The <a name="prestransl">translation rules associated with specific
1.18 cvs 7645: presentation rules</a> can use the value of the specific presentation rule
1.1 cvs 7646: that causes them to be applied. This behavior is designated by the keyword
1.18 cvs 7647: <tt>Value</tt>. For numerically-valued presentation rules, the numeric value
1.1 cvs 7648: is produced. For other presentation rules, the name of the value is
1.18 cvs 7649: produced.</p>
1.30 cvs 7650:
7651: <p>It should be noted that modifications to the layout of the document's
7652: elements that are made using the combination of the control key and a mouse
7653: button will have no effect on the translation of the document.</p>
7654:
7655: <blockquote class="example">
7656: <p><strong>Example:</strong></p>
7657:
7658: <p>Suppose that it is desirable to use the same font sizes as in the
7659: specific presentation, but the font size must be between 10 and 18
7660: typographer's points. If font size is set in the translated document by the
7661: string <tt>pointsize=n</tt> where <tt>n</tt> is the font size in
7662: typographer's points then the following rules will suffice:</p>
7663: <pre>PRESENTATION
1.1 cvs 7664: Size < 10 :
7665: Create 'pointsize=10';
7666: Size in [10..18] :
7667: BEGIN
7668: Create 'pointsize=';
7669: Create Value;
7670: END;
1.30 cvs 7671: Size > 18 :
1.18 cvs 7672: Create 'pointsize=18';</pre>
7673: </blockquote>
7674: </div>
1.1 cvs 7675:
1.18 cvs 7676: <div class="subsection">
1.30 cvs 7677: <h3><a name="sectc5225">Recoding of characters, symbols and graphics</a></h3>
1.1 cvs 7678:
1.30 cvs 7679: <p>The coding of characters, graphical elements and symbols as defined in Thot
1.1 cvs 7680: does not necessarily correspond to what is required by an application to which
7681: a Thot document must be exported. Because of this the translator can recode
7682: these terminal elements of the documents structure. The last sections of a
7683: translation schema are intended for this purpose, each specifying the recoding
1.18 cvs 7684: rules for one type of terminal element.</p>
1.30 cvs 7685:
7686: <p>The recoding rules for character strings are grouped by alphabets. There is
7687: a group of rules for each alphabet of the Thot document that must be
7688: translated. Each such group of rules begins with the <tt>TEXTTRANSLATE</tt>
7689: keyword, followed by the specification of the alphabet to translate and the
7690: recoding rules, between the <tt>BEGIN</tt> and <tt>END</tt> keywords unless
7691: there is only one recoding rule for the alphabet. The specification of the
7692: alphabet is not required: by default it is assumed to the Latin alphabet (the
7693: ISO Latin-1 character set).</p>
7694:
7695: <p>Each recoding rule is formed by a source string between apostrophes and a
1.1 cvs 7696: target string, also between apostrophes, the two strings being separated by
1.30 cvs 7697: the arrow symbol (<tt>-></tt>), formed by the ``minus'' and ``greater
7698: than'' characters. The rule is terminated by a semi-colon.</p>
1.18 cvs 7699: <pre> TextTransSeq = [ Alphabet ] TransSeq .
1.1 cvs 7700: Alphabet = NAME .
1.30 cvs 7701: TransSeq ='BEGIN' < Translation > 'END' ';' /
1.1 cvs 7702: Translation .
1.30 cvs 7703: Translation = Source [ '->' Target ] ';' .
1.1 cvs 7704: Source = STRING .
1.18 cvs 7705: Target = STRING .</pre>
1.30 cvs 7706:
7707: <p>One such rule signifies that when the source string appears in a text leaf
7708: of the document being translated, the translator must replace it, in the
1.1 cvs 7709: translated document, with the target string. The source string and the target
7710: string can have different lengths and the target string can be empty. In this
7711: last case, the translator simply suppresses every occurrence of the source
1.18 cvs 7712: string in the translated document.</p>
1.30 cvs 7713:
7714: <p>For a given alphabet, the order of the rules is not important and has no
1.1 cvs 7715: significance because the T language compiler reorders the rules in ways that
7716: speed up the translator's work. The total number of recoding rules is limited
1.18 cvs 7717: by the compiler as is the maximum length of the source and target strings.</p>
1.30 cvs 7718:
7719: <p>The recoding rules for symbols and graphical elements are written in the
7720: same manner as the recoding rules for character strings. They are preceded,
1.18 cvs 7721: respectively, by the <tt>SYMBTRANSLATE</tt> and <tt>GRAPHTRANSLATE</tt> and so
1.1 cvs 7722: not require a specification of the alphabet. Their source string is limited to
7723: one character, since, in Thot, each symbol and each graphical element is
7724: represented by a single character. The symbol and graphical element codes are
1.18 cvs 7725: defined along with the <a href="#sect7">non-standard character codes</a>.</p>
1.30 cvs 7726:
1.18 cvs 7727: <blockquote class="example">
1.30 cvs 7728: <p><strong>Example:</strong></p>
7729:
7730: <p>In a translation schema producing documents destined for use with the
7731: L<sup>A</sup>T<sub><big>E</big></sub>X formatter, the Latin characters``é''
7732: (octal code 351 in Thot) and ``č'' (octal code 350 in Thot) must be
7733: converted to their representation in
7734: L<sup>A</sup>T<sub><big>E</big></sub>X:</p>
7735: <pre>TEXTTRANSLATE Latin
1.1 cvs 7736: BEGIN
1.30 cvs 7737: '\350' -> '\`{e}'; { e grave }
7738: '\351' -> '\''{e}'; { e acute }
1.18 cvs 7739: END;</pre>
7740: </blockquote>
7741: </div>
7742: </div>
7743: <hr>
7744: </div>
1.1 cvs 7745:
1.18 cvs 7746: <div class="chapter">
1.30 cvs 7747: <h1><a name="sect6">Language grammars</a></h1>
1.1 cvs 7748:
1.30 cvs 7749: <p>This chapter gives the complete grammars of the languages of Thot. The
1.1 cvs 7750: grammars were presented and described in the preceding chapters, which also
7751: specify the semantics of the languages. This section gives only the
1.18 cvs 7752: syntax.</p>
1.1 cvs 7753:
1.18 cvs 7754: <div class="section">
1.30 cvs 7755: <h2><a name="sectb61">The M meta-language</a></h2>
1.1 cvs 7756:
1.30 cvs 7757: <p>The language grammars are all expressed in the same formalism, the M
1.18 cvs 7758: meta-language, which is defined in this section.</p>
7759: <pre>{ Any text between braces is a comment. }
1.30 cvs 7760: Grammar = Rule < Rule > 'END' .
7761: { The < and > signs indicate zero }
1.1 cvs 7762: { or more repetitions. }
7763: { END marks the end of the grammar. }
7764: Rule = Ident '=' RightPart '.' .
7765: { The period indicates the end of a rule }
7766: RightPart = RtTerminal / RtIntermed .
7767: { The slash indicates a choice }
7768: RtTerminal ='NAME' / 'STRING' / 'NUMBER' .
7769: { Right part of a terminal rule }
1.30 cvs 7770: RtIntermed = Possibility < '/' Possibility > .
1.1 cvs 7771: { Right part of an intermediate rule }
1.30 cvs 7772: Possibility = ElemOpt < ElemOpt > .
7773: ElemOpt = Element / '[' Element < Element > ']' /
7774: '<' Element < Element > '>' .
1.1 cvs 7775: { Brackets delimit optional parts }
7776: Element = Ident / KeyWord .
7777: Ident = NAME .
7778: { Identifier, sequence of characters
7779: KeyWord = STRING .
7780: { Character string delimited by apostrophes }
1.18 cvs 7781: END</pre>
7782: </div>
1.1 cvs 7783:
1.18 cvs 7784: <div class="section">
1.30 cvs 7785: <h2><a name="sectb62">The S language</a></h2>
1.1 cvs 7786:
1.30 cvs 7787: <p>The S language is used to write structure schemas, which contain the
7788: generic logical structures of document and object classes. It is described
7789: here in the M meta-language.</p>
1.18 cvs 7790: <pre>StructSchema = 'STRUCTURE' [ 'EXTENSION' ] ElemID ';'
1.1 cvs 7791: 'DEFPRES' PresID ';'
7792: [ 'ATTR' AttrSeq ]
7793: [ 'STRUCT' RulesSeq ]
7794: [ 'EXTENS' ExtensRuleSeq ]
7795: [ 'ASSOC' RulesSeq ]
7796: [ 'UNITS' RulesSeq ]
7797: [ 'EXPORT' SkeletonSeq ]
7798: [ 'EXCEPT' ExceptSeq ]
7799: 'END' .
7800:
7801: ElemID = NAME .
7802: PresID = NAME .
7803:
1.30 cvs 7804: AttrSeq = Attribute < Attribute > .
1.1 cvs 7805: Attribute = AttrID '=' AttrType ';' .
7806: AttrType = 'INTEGER' / 'TEXT' /
7807: 'REFERENCE' '(' RefType ')' /
7808: ValueSeq .
7809: RefType = 'ANY' /
7810: [ FirstSec ] ElemID [ ExtStruct ] .
1.30 cvs 7811: ValueSeq = AttrVal < ',' AttrVal > .
1.1 cvs 7812: AttrID = NAME .
7813: FirstSec = 'First' / 'Second' .
7814: ExtStruct = '(' ElemID ')' .
7815: AttrVal = NAME .
7816:
1.30 cvs 7817: RulesSeq = Rule < Rule > .
1.1 cvs 7818: Rule = ElemID [ LocAttrSeq ] '='
7819: DefWithAttr ';' .
7820: LocAttrSeq = '(' 'ATTR' LocalAttr
1.30 cvs 7821: < ';' LocalAttr > ')' .
1.1 cvs 7822: LocalAttr = [ '!' ] AttrID [ '=' AttrType ] .
7823: DefWithAttr = Definition
7824: [ '+' '(' ExtensionSeq ')' ]
7825: [ '-' '(' RestrictSeq ')' ]
7826: [ 'WITH' FixedAttrSeq ] .
1.30 cvs 7827: ExtensionSeq = ExtensionElem < ',' ExtensionElem > .
1.1 cvs 7828: ExtensionElem = ElemID / 'TEXT' / 'GRAPHICS' /
7829: 'SYMBOL' / 'PICTURE' .
1.30 cvs 7830: RestrictSeq = RestrictElem < ',' RestrictElem > .
1.1 cvs 7831: RestrictElem = ElemID / 'TEXT' / 'GRAPHICS' /
7832: 'SYMBOL' / 'PICTURE' .
1.30 cvs 7833: FixedAttrSeq = FixedAttr < ',' FixedAttr > .
1.1 cvs 7834: FixedAttr = AttrID [ FixedOrModifVal ] .
7835: FixedOrModifVal= [ '?' ] '=' FixedValue .
7836: FixedValue = [ '-' ] NumValue / TextValue / AttrVal .
7837: NumValue = NUMBER .
7838: TextValue = STRING .
7839:
7840: Definition = BaseType [ LocAttrSeq ] / Constr /
7841: Element .
7842: BaseType = 'TEXT' / 'GRAPHICS' / 'SYMBOL' /
7843: 'PICTURE' / 'UNIT' / 'NATURE' .
7844: Element = ElemID [ ExtOrDef ] .
7845: ExtOrDef = 'EXTERN' / 'INCLUDED' /
7846: [ LocAttrSeq ] '=' Definition .
7847:
7848: Constr = 'LIST' [ '[' min '..' max ']' ] 'OF'
7849: '(' DefWithAttr ')' /
7850: 'BEGIN' DefOptSeq 'END' /
7851: 'AGGREGATE' DefOptSeq 'END' /
7852: 'CASE' 'OF' DefSeq 'END' /
7853: 'REFERENCE' '(' RefType ')' /
7854: 'PAIR' .
7855:
7856: min = Integer / '*' .
7857: max = Integer / '*' .
7858: Integer = NUMBER .
7859:
1.30 cvs 7860: DefOptSeq = DefOpt ';' < DefOpt ';' > .
1.1 cvs 7861: DefOpt = [ '?' ] DefWithAttr .
7862:
1.30 cvs 7863: DefSeq = DefWithAttr ';' < DefWithAttr ';' > .
1.1 cvs 7864:
1.30 cvs 7865: SkeletonSeq = SkeletonElem < ',' SkeletonElem > ';' .
1.1 cvs 7866: SkeletonElem = ElemID [ 'WITH' Contents ] .
7867: Contents = 'Nothing' / ElemID [ ExtStruct ] .
7868:
1.30 cvs 7869: ExceptSeq = Except ';' < Except ';' > .
1.1 cvs 7870: Except = [ 'EXTERN' ] [ FirstSec ] ExcTypeOrAttr ':'
7871: ExcValSeq .
7872: ExcTypeOrAttr = ElemID / AttrID .
1.30 cvs 7873: ExcValSeq = ExcValue < ',' ExcValue > .
1.1 cvs 7874: ExcValue = 'NoCut' / 'NoCreate' /
7875: 'NoHMove' / 'NoVMove' / 'NoMove' /
7876: 'NoHResize' / 'NoVResize' / 'NoResize' /
1.18 cvs 7877: 'MoveResize' /
1.1 cvs 7878: 'NewWidth' / 'NewHeight' /
7879: 'NewHPos' / 'NewVPos' /
7880: 'Invisible' / 'NoSelect' /
7881: 'Hidden' / 'ActiveRef' /
7882: 'ImportLine' / 'ImportParagraph' /
1.9 cvs 7883: 'NoPaginate' / 'ParagraphBreak' /
7884: 'HighlightChildren' / 'ExtendedSelection' /
1.36 ! cvs 7885: 'SelectParent' / 'ClickableSurface' /
1.29 cvs 7886: 'ReturnCreateNL' / 'ReturnCreateWithin' .
1.1 cvs 7887:
1.30 cvs 7888: ExtensRuleSeq = ExtensRule ';' < ExtensRule ';' > .
1.1 cvs 7889: ExtensRule = RootOrElem [ LocAttrSeq ]
7890: [ '+' '(' ExtensionSeq ')' ]
7891: [ '-' '(' RestrictSeq ')' ]
7892: [ 'WITH' FixedAttrSeq ] .
7893: RootOrElem = 'Root' / ElemID .
7894:
1.18 cvs 7895: END</pre>
7896: </div>
1.1 cvs 7897:
1.18 cvs 7898: <div class="section">
1.30 cvs 7899: <h2><a name="sectb63">The P language</a></h2>
1.1 cvs 7900:
1.30 cvs 7901: <p>The P language is used to write presentation schemas, which define the
1.1 cvs 7902: graphical presentation rules to be applied to different classes of documents
1.18 cvs 7903: and objects. It is described here in the M meta-language.</p>
7904: <pre>PresSchema = 'PRESENTATION' ElemID ';'
1.1 cvs 7905: [ 'VIEWS' ViewSeq ]
7906: [ 'PRINT' PrintViewSeq ]
7907: [ 'COUNTERS' CounterSeq ]
7908: [ 'CONST' ConstSeq ]
7909: [ 'VAR' VarSeq ]
7910: [ 'DEFAULT' ViewRuleSeq ]
7911: [ 'BOXES' BoxSeq ]
7912: [ 'RULES' PresentSeq ]
7913: [ 'ATTRIBUTES' PresAttrSeq ]
7914: [ 'TRANSMIT' TransmitSeq ]
7915: 'END' .
7916:
7917: ElemID = NAME .
7918:
7919: ViewSeq = ViewDeclaration
1.30 cvs 7920: < ',' ViewDeclaration > ';' .
1.1 cvs 7921: ViewDeclaration = ViewID [ 'EXPORT' ] .
7922: ViewID = NAME .
7923:
1.30 cvs 7924: PrintViewSeq = PrintView < ',' PrintView > ';' .
1.1 cvs 7925: PrintView = ViewID / ElemID .
7926:
1.30 cvs 7927: CounterSeq = Counter < Counter > .
1.1 cvs 7928: Counter = CounterID ':' CounterFunc ';' .
7929: CounterID = NAME .
7930: CounterFunc = 'RANK' 'OF' TypeOrPage [ SLevelAsc ]
7931: [ 'INIT' AttrID ] [ 'REINIT' AttrID ] /
1.30 cvs 7932: SetFunction < SetFunction >
7933: AddFunction < AddFunction >
1.1 cvs 7934: [ 'INIT' AttrID ] /
1.16 cvs 7935: 'RLEVEL' 'OF' ElemID .
1.1 cvs 7936: SLevelAsc = [ '-' ] LevelAsc .
7937: LevelAsc = NUMBER .
7938: SetFunction = 'SET' CounterValue 'ON' TypeOrPage .
7939: AddFunction = 'ADD' CounterValue 'ON' TypeOrPage .
7940: TypeOrPage = 'Page' [ '(' ViewID ')' ] /
1.16 cvs 7941: [ '*' ] ElemID .
1.1 cvs 7942: CounterValue = NUMBER .
7943:
1.30 cvs 7944: ConstSeq = Const < Const > .
1.1 cvs 7945: Const = ConstID '=' ConstType ConstValue ';' .
7946: ConstID = NAME .
7947: ConstType = 'Text' [ Alphabet ] / 'Symbol' /
7948: 'Graphics' / 'Picture' .
7949: ConstValue = STRING .
7950: Alphabet = NAME .
7951:
1.30 cvs 7952: VarSeq = Variable < Variable > .
1.1 cvs 7953: Variable = VarID ':' FunctionSeq ';' .
7954: VarID = NAME .
1.30 cvs 7955: FunctionSeq = Function < Function > .
1.1 cvs 7956: Function = 'DATE' / 'FDATE' /
7957: 'DocName' / 'DirName' /
7958: 'ElemName' / 'AttributeName' /
7959: ConstID / ConstType ConstValue /
7960: AttrID /
7961: 'VALUE' '(' PageAttrCtr ','
7962: CounterStyle ')' .
7963: PageAttrCtr = 'PageNumber' [ '(' ViewID ')' ] /
7964: [ MinMax ] CounterID / AttrID .
7965: CounterStyle = 'Arabic' / 'LRoman' / 'URoman' /
7966: 'Uppercase' / 'Lowercase' .
7967: MinMax = 'MaxRangeVal' / 'MinRangeVal' .
7968:
1.30 cvs 7969: BoxSeq = Box < Box > .
1.1 cvs 7970: Box = 'FORWARD' BoxID ';' /
7971: BoxID ':' ViewRuleSeq .
7972: BoxID = NAME .
7973:
1.30 cvs 7974: PresentSeq = Present < Present > .
1.1 cvs 7975: Present = [ '*' ] [ FirstSec ] ElemID ':'
7976: ViewRuleSeq .
7977: FirstSec = 'First' / 'Second' .
7978:
1.30 cvs 7979: PresAttrSeq = PresAttr < PresAttr > .
1.1 cvs 7980: PresAttr = AttrID [ '(' [ FirstSec ] ElemID ')' ]
7981: [ AttrRelation ] ':' ViewRuleSeq .
7982: AttrID = NAME .
7983: AttrRelation = '=' AttrVal /
1.30 cvs 7984: '>' [ '-' ] MinValue /
1.1 cvs 7985: '<' [ '-' ] MaxValue /
7986: 'IN' '[' [ '-' ] LowerBound '..'
7987: [ '-' ] UpperBound ']' /
7988: 'GREATER' AttrID /
7989: 'EQUAL' AttrID /
7990: 'LESS' AttrID .
7991: AttrVal = [ '-' ] EqualNum / EqualText / AttrValue .
7992: MinValue = NUMBER .
7993: MaxValue = NUMBER .
7994: LowerBound = NUMBER .
7995: UpperBound = NUMBER.
7996: EqualNum = NUMBER .
7997: EqualText = STRING .
7998: AttrValue = NAME .
7999:
1.30 cvs 8000: ViewRuleSeq = 'BEGIN' < RulesAndCond > < ViewRules >
1.1 cvs 8001: 'END' ';' /
8002: ViewRules / CondRules / Rule .
8003: RulesAndCond = CondRules / Rule .
8004: ViewRules = 'IN' ViewID CondRuleSeq .
1.30 cvs 8005: CondRuleSeq = 'BEGIN' < RulesAndCond > 'END' ';' /
1.1 cvs 8006: CondRules / Rule .
1.30 cvs 8007: CondRules = CondRule < CondRule >
1.1 cvs 8008: [ 'Otherwise' RuleSeq ] .
8009: CondRule = 'IF' ConditionSeq RuleSeq .
1.30 cvs 8010: RulesSeq = 'BEGIN' Rule < Rule > 'END' ';' / Rule .
1.1 cvs 8011:
1.30 cvs 8012: ConditionSeq = Condition < 'AND' Condition > .
1.6 cvs 8013: Condition = [ 'NOT' ] [ 'Target' ] ConditionElem .
8014: ConditionElem = 'First' / 'Last' /
8015: [ 'Immediately' ] 'Within' [ NumParent ]
8016: ElemID [ ExtStruct ] /
8017: ElemID /
8018: 'Referred' / 'FirstRef' / 'LastRef' /
8019: 'ExternalRef' / 'InternalRef' / 'CopyRef' /
8020: 'AnyAttributes' / 'FirstAttr' / 'LastAttr' /
8021: 'UserPage' / 'StartPage' / 'ComputedPage' /
1.33 cvs 8022: 'Empty' / 'Root' /
1.6 cvs 8023: '(' [ MinMax ] CounterName CounterCond ')' /
8024: CondPage '(' CounterID ')' .
8025: NumParent = [ GreaterLess ] NParent .
1.30 cvs 8026: GreaterLess = '>' / '<' .
1.6 cvs 8027: NParent = NUMBER.
1.30 cvs 8028: CounterCond = '<' MaxCtrVal / '>' MinCtrVal /
1.6 cvs 8029: '=' EqCtrVal /
8030: 'IN' '[' ['-'] MinCtrBound '..'
8031: ['-'] MaxCtrBound ']' .
8032: PageCond = 'Even' / 'Odd' / 'One' .
8033: MaxCtrVal = NUMBER .
8034: MinCtrVal = NUMBER .
8035: EqCtrVal = NUMBER .
8036: MaxCtrBound = NUMBER .
8037: MinCtrBound = NUMBER .
1.1 cvs 8038:
1.34 cvs 8039: Rule = Property ';' / PresFunc ';' .
8040: Property = 'VertRef' ':' HorizPosition /
1.1 cvs 8041: 'HorizRef' ':' VertPosition /
8042: 'VertPos' ':' VPos /
8043: 'HorizPos' ':' HPos /
8044: 'Height' ':' Extent /
8045: 'Width' ':' Extent /
8046: 'VertOverflow' ':' Boolean /
8047: 'HorizOverflow' ':' Boolean /
1.26 cvs 8048: 'MarginTop' ':' MarginWidth /
8049: 'MarginRight' ':' MarginWidth /
8050: 'MarginBottom' ':' MarginWidth /
8051: 'MarginLeft' ':' MarginWidth /
8052: 'PaddingTop' ':' PaddingWidth /
8053: 'PaddingRight' ':' PaddingWidth /
8054: 'PaddingBottom' ':' PaddingWidth /
8055: 'PaddingLeft' ':' PaddingWidth /
8056: 'BorderTopWidth' ':' BorderWidth /
8057: 'BorderRightWidth' ':' BorderWidth /
8058: 'BorderBottomWidth' ':' BorderWidth /
8059: 'BorderLeftWidth' ':' BorderWidth /
8060: 'BorderTopColor' ':' BorderColor /
8061: 'BorderRightColor' ':' BorderColor /
8062: 'BorderBottomColor' ':' BorderColor /
8063: 'BorderLeftColor' ':' BorderColor /
8064: 'BorderTopStyle' ':' BorderStyle /
8065: 'BorderRightStyle' ':' BorderStyle /
8066: 'BorderBottomStyle' ':' BorderStyle /
8067: 'BorderLeftStyle' ':' BorderStyle .
1.1 cvs 8068: 'LineSpacing' ':' DistOrInherit /
8069: 'Indent' ':' DistOrInherit /
8070: 'Adjust' ':' AlignOrInherit /
8071: 'Hyphenate' ':' BoolInherit /
8072: 'PageBreak' ':' Boolean /
8073: 'LineBreak' ':' Boolean /
8074: 'InLine' ':' Boolean /
8075: 'NoBreak1' ':' AbsDist /
8076: 'NoBreak2' ':' AbsDist /
8077: 'Gather' ':' Boolean /
8078: 'Visibility' ':' NumberInherit /
8079: 'Size' ':' SizeInherit /
8080: 'Font' ':' NameInherit /
8081: 'Style' ':' StyleInherit /
1.23 cvs 8082: 'Weight' ':' WeightInherit /
1.1 cvs 8083: 'Underline' ':' UnderLineInherit /
8084: 'Thickness' ':' ThicknessInherit /
8085: 'Depth' ':' NumberInherit /
8086: 'LineStyle' ':' LineStyleInherit /
8087: 'LineWeight' ':' DistOrInherit /
8088: 'FillPattern' ':' NameInherit /
1.30 cvs 8089: 'Background' ':' Color /
8090: 'Foreground' ':' Color /
1.1 cvs 8091: 'Content' ':' VarConst .
8092: PresFunc = Creation '(' BoxID ')' /
8093: 'Line' /
8094: 'NoLine' /
8095: 'Page' '(' BoxID ')' /
1.13 cvs 8096: 'Copy' '(' BoxTypeToCopy ')' /
8097: 'ShowBox' /
1.18 cvs 8098: 'BackgroundPicture' ':' FileName /
8099: 'PictureMode' ':' PictMode .
1.1 cvs 8100:
8101: BoxTypeToCopy = BoxID [ ExtStruct ] /
8102: ElemID [ ExtStruct ] .
8103: ExtStruct = '(' ElemID ')' .
8104:
8105: Distance = [ Sign ] AbsDist .
8106: Sign = '+' / '-' .
8107: AbsDist = IntegerOrAttr [ '.' DecimalPart ]
8108: [ Unit ] .
8109: IntegerOrAttr = IntegerPart / AttrID .
8110: IntegerPart = NUMBER .
8111: DecimalPart = NUMBER .
8112: Unit = 'em' / 'ex' / 'cm' / 'mm' / 'in' / 'pt' /
8113: 'pc' / 'px' / '%' .
8114:
8115: HPos = 'nil' / VertAxis '=' HorizPosition
8116: [ 'UserSpecified' ] .
8117: VPos = 'nil' / HorizAxis '=' VertPosition
8118: [ 'UserSpecified' ] .
8119: VertAxis = 'Left' / 'VMiddle' / 'VRef' / 'Right' .
8120: HorizAxis = 'Top' / 'HMiddle' / 'HRef' / 'Bottom' .
8121:
1.6 cvs 8122: VertPosition = Reference '.' HorizAxis [ Distance ] .
8123: HorizPosition = Reference '.' VertAxis [ Distance ] .
8124: Reference = 'Enclosing' [ BoxTypeNot ] /
8125: 'Enclosed' [ BoxTypeNot ] /
8126: 'Previous' [ BoxTypeNot ] /
8127: 'Next' [ BoxTypeNot ] /
8128: 'Referred' [ BoxTypeNot ] /
8129: 'Creator' /
8130: 'Root' /
8131: '*' /
8132: BoxOrType .
8133: BoxOrType = BoxID /
8134: [ '*' ] [ FirstSec ] ElemID /
1.17 cvs 8135: 'AnyElem' / 'AnyBox' /
8136: 'ElemWithAttr' AttrID .
1.6 cvs 8137: BoxTypeNot = [ 'NOT' ] BoxOrType .
8138:
8139: Extent = Reference '.' HeightWidth
8140: [ Relation ] [ 'Min' ] /
8141: AbsDist [ 'UserSpecified' ] [ 'Min' ] /
8142: HPos / VPos .
8143: HeightWidth = 'Height' / 'Width' .
8144: Relation = '*' ExtentAttr '%' / Distance .
8145: ExtentAttr = ExtentVal / AttrID .
8146: ExtentVal = NUMBER .
1.26 cvs 8147:
8148: MarginWidth = InheritParent / 'Auto' / Distance .
8149: PaddingWidth = InheritParent / Distance .
8150: BorderWidth = InheritParent / 'Thin' / 'Medium' / 'Thick' / Distance .
8151: BorderColor = InheritParent / 'Transparent' / 'Foreground' /
8152: ColorName .
8153: BorderStyle = InheritParent /
8154: 'None' / 'Hidden' / 'Dotted' / 'Dashed' / 'Solid' /
8155: 'Double' / 'Groove' / 'Ridge' / 'Inset' / 'Outset' .
1.27 cvs 8156: InheritParent = 'Enclosing' '=' / 'Creator' '=' .
1.26 cvs 8157: ColorName = NAME .
1.6 cvs 8158:
8159: Inheritance = Kinship InheritedValue .
8160: Kinship = 'Enclosing' / 'GrandFather'/ 'Enclosed' /
8161: 'Previous' / 'Creator' .
8162: InheritedValue = '+' PosIntAttr [ 'Max' maximumA ] /
8163: '-' NegIntAttr [ 'Min' minimumA ] /
8164: '=' .
8165: PosIntAttr = PosInt / AttrID .
8166: PosInt = NUMBER .
8167: NegIntAttr = NegInt / AttrID .
8168: NegInt = NUMBER .
8169: maximumA = maximum / AttrID .
8170: maximum = NUMBER .
8171: minimumA = minimum / AttrID .
8172: minimum = NUMBER .
8173:
8174: AlignOrInherit = Kinship '=' / Alignment .
8175: Alignment = 'Left' / 'Right' / 'VMiddle' /
8176: 'LeftWithDots' .
1.1 cvs 8177:
1.6 cvs 8178: DistOrInherit = Kinship InheritedDist / Distance .
8179: InheritedDist = '=' / '+' AbsDist / '-' AbsDist .
1.1 cvs 8180:
1.6 cvs 8181: BoolInherit = Boolean / Kinship '=' .
8182: Boolean = 'Yes' / 'No' .
1.1 cvs 8183:
1.6 cvs 8184: NumberInherit = Integer / AttrID / Inheritance .
8185: Integer = NUMBER .
1.1 cvs 8186:
8187: LineStyleInherit= Kinship '=' / 'Solid' / 'Dashed' /
8188: 'Dotted' .
8189:
1.6 cvs 8190: SizeInherit = SizeAttr [ 'pt' ] / Kinship InheritedSize .
8191: InheritedSize = '+' SizeAttr [ 'pt' ]
8192: [ 'Max' MaxSizeAttr ] /
8193: '-' SizeAttr [ 'pt' ]
8194: [ 'Min' MinSizeAttr ] /
1.22 cvs 8195: '*' PercentSizeAttr '%' /
1.6 cvs 8196: '=' .
8197: SizeAttr = Size / AttrID .
8198: Size = NUMBER .
8199: MaxSizeAttr = MaxSize / AttrID .
8200: MaxSize = NUMBER .
8201: MinSizeAttr = MinSize / AttrID .
8202: MinSize = NUMBER .
1.22 cvs 8203: PercentSizeAttr = PercentSize / AttrID .
8204: PercentSize = NUMBER .
1.6 cvs 8205:
8206: NameInherit = Kinship '=' / FontName .
8207: FontName = NAME .
1.30 cvs 8208: Color = 'Transparent' / Kinship '=' / FontName .
1.6 cvs 8209: StyleInherit = Kinship '=' /
1.23 cvs 8210: 'Roman' / 'Italics' / 'Oblique' .
8211: WeightInherit = Kinship '=' /
8212: 'Normal' / 'Bold' .
1.1 cvs 8213: UnderLineInherit= Kinship '=' /
1.6 cvs 8214: 'NoUnderline' / 'Underlined' /
8215: 'Overlined' / 'CrossedOut' .
1.1 cvs 8216: ThicknessInherit= Kinship '=' / 'Thick' / 'Thin' .
1.13 cvs 8217:
8218: FileName = STRING .
8219: PictMode = 'NormalSize' / 'Scale' /
8220: 'RepeatXY' / 'RepeatX' / 'RepeatY' .
1.1 cvs 8221:
1.6 cvs 8222: VarConst = ConstID / ConstType ConstValue /
8223: VarID / '(' FunctionSeq ')' /
8224: ElemID .
8225:
8226: Creation = Create [ 'Repeated' ] .
8227: Create = 'CreateFirst' / 'CreateLast' /
8228: 'CreateBefore' / 'CreateAfter' /
8229: 'CreateEnclosing' .
8230:
1.30 cvs 8231: TransmitSeq = Transmit < Transmit > .
1.6 cvs 8232: Transmit = TypeOrCounter 'To' ExternAttr
8233: '(' ElemID ')' ';' .
8234: TypeOrCounter = CounterID / ElemID .
8235: ExternAttr = NAME .
1.1 cvs 8236:
1.18 cvs 8237: END</pre>
8238: </div>
1.1 cvs 8239:
1.18 cvs 8240: <div class="section">
8241: <h2><a name="sectb64">The T language</a></h2>
8242: <pre>TransSchema = 'TRANSLATION' ElemID ';'
1.1 cvs 8243: [ 'LINELENGTH' LineLength ';' ]
8244: [ 'LINEEND' CHARACTER ';' ]
8245: [ 'LINEENDINSERT' STRING ';' ]
8246: [ 'BUFFERS' BufferSeq ]
8247: [ 'COUNTERS' CounterSeq ]
8248: [ 'CONST' ConstSeq ]
8249: [ 'VAR' VariableSeq ]
8250: 'RULES' ElemSeq
8251: [ 'ATTRIBUTES' AttrSeq ]
8252: [ 'PRESENTATION' PresSeq ]
1.30 cvs 8253: < 'TEXTTRANSLATE' TextTransSeq >
1.1 cvs 8254: [ 'SYMBTRANSLATE' TransSeq ]
8255: [ 'GRAPHTRANSLATE' TransSeq ]
8256: 'END' .
8257:
8258: LineLength = NUMBER .
8259:
1.30 cvs 8260: BufferSeq = Buffer < Buffer > .
1.1 cvs 8261: Buffer = BufferID [ '(' 'Picture' ')' ] ';' .
8262: BufferID = NAME .
8263:
1.30 cvs 8264: CounterSeq = Counter < Counter > .
1.1 cvs 8265: Counter = CounterID [ ':' CounterFunc ] ';' .
8266: CounterID = NAME .
8267: CounterFunc = 'Rank' 'of' ElemID [ SLevelAsc ]
8268: [ 'Init' AttrID ] /
8269: 'Rlevel' 'of' ElemID /
8270: 'Set' InitValue 'On' ElemID
8271: 'Add' Increment 'On' ElemID
8272: [ 'Init' AttrID ] .
8273: SLevelAsc = [ '-' ] LevelAsc .
8274: LevelAsc = NUMBER .
8275: InitValue = NUMBER .
8276: Increment = NUMBER .
8277: ElemID = NAME .
8278: AttrID = NAME .
8279:
1.30 cvs 8280: ConstSeq = Const < Const > .
1.1 cvs 8281: Const = ConstID '=' ConstValue ';' .
8282: ConstID = NAME .
8283: ConstValue = STRING .
8284:
1.30 cvs 8285: VariableSeq = Variable < Variable > .
8286: Variable = VarID ':' Function < Function > ';' .
1.1 cvs 8287: VarID = NAME .
8288: Function = 'Value' '(' CounterID [ ':' Length ]
8289: [ ',' CounterStyle ] ')' /
8290: 'FileDir' / 'FileName' / 'Extension' /
8291: 'DocumentName' / 'DocumentDir' /
8292: ConstID / CharString /
8293: BufferID / AttrID .
8294: Length = NUMBER .
8295: CounterStyle= 'Arabic' / 'LRoman' / 'URoman' /
8296: 'Uppercase' / 'Lowercase' .
8297: CharString = STRING .
8298:
1.30 cvs 8299: ElemSeq = TransType < TransType > .
1.1 cvs 8300: TransType = [ FirstSec ] ElemID ':' RuleSeq .
8301: FirstSec = 'First' / 'Second' .
1.30 cvs 8302: RuleSeq = Rule / 'BEGIN' < Rule > 'END' ';' .
1.1 cvs 8303: Rule = SimpleRule / ConditionBlock .
8304: ConditionBlock= 'IF' ConditionSeq SimpleRuleSeq .
1.30 cvs 8305: SimpleRuleSeq = 'BEGIN' < SimpleRule > 'END' ';' /
1.1 cvs 8306: SimpleRule .
8307:
8308: ConditionSeq = Condition [ 'AND' Condition ] .
8309: Condition = [ 'NOT' ] [ 'Target' ] Cond .
8310: Cond = CondElem / CondAscend .
8311: CondElem = 'FirstRef' / 'LastRef' /
8312: 'ExternalRef' /
8313: 'Alphabet' '=' Alphabet /
8314: 'ComputedPage' / 'StartPage' /
8315: 'UserPage' / 'ReminderPage' /
8316: 'Empty' /
1.18 cvs 8317: ElemID /
1.1 cvs 8318: 'FirstAttr' / 'LastAttr' .
8319: CondAscend = [ Ascend ] CondOnAscend .
8320: Ascend = '*' / 'Parent' / 'Ancestor' LevelOrType .
8321: LevelOrType = CondRelLevel / ElemID [ ExtStruct ] .
8322: CondRelLevel = NUMBER .
8323: CondOnAscend = 'First' / 'Last' /
8324: 'Referred' /
8325: [ 'Immediately' ] 'Within' [ NumParent ]
8326: ElemID [ ExtStruct ] /
8327: 'Attributes' /
8328: AttrID [ RelatAttr ] /
8329: 'Presentation' /
1.34 cvs 8330: PresRule .
1.1 cvs 8331: NumParent = [ GreaterLess ] NParent .
1.30 cvs 8332: GreaterLess = '>' / '<' .
1.1 cvs 8333: NParent = NUMBER.
8334: Alphabet = NAME .
8335: RelatAttr = '=' Value /
1.30 cvs 8336: '>' [ '-' ] Minimum /
1.1 cvs 8337: '<' [ '-' ] Maximum /
8338: 'IN' '[' [ '-' ] MinInterval '..'
8339: [ '-' ] MaxInterval ']' .
8340: Value = [ '-' ] IntegerVal / TextVal / AttrValue .
8341: Minimum = NUMBER .
8342: Maximum = NUMBER .
8343: MinInterval = NUMBER .
8344: MaxInterval = NUMBER .
8345: IntegerVal = NUMBER .
8346: TextVal = STRING .
8347: AttrValue = NAME .
8348:
8349: SimpleRule = 'Create' [ 'IN' VarID ] Object
8350: [ Position ] ';' /
8351: 'Write' Object [ Position ] ';' /
8352: 'Read' BufferID [ Position ] ';' /
8353: 'Include' File [ Position ] ';' /
1.6 cvs 8354: 'Get' [ RelPosition ] ElemID
8355: [ ExtStruct ]
8356: [ Position ] ';' /
1.1 cvs 8357: 'Copy' [ RelPosition ] ElemID
8358: [ ExtStruct ]
8359: [ Position ] ';' /
8360: 'Use' TrSchema [ 'For' ElemID ] ';' /
8361: 'Remove' ';' /
1.31 cvs 8362: 'Ignore' ';' /
1.1 cvs 8363: 'NoTranslation' ';' /
8364: 'NoLineBreak' ';' /
8365: 'ChangeMainFile' VarID [ Position ] ';' /
1.14 cvs 8366: 'RemoveFile' VarID [ Position ] ';' /
1.10 cvs 8367: 'Set' CounterID InitValue [ Position ] ';' /
8368: 'Add' CounterID Increment [ Position ] ';' /
1.25 cvs 8369: 'Indent' [ 'IN' VarID ] Indent [ Position ] ';' .
1.10 cvs 8370:
1.25 cvs 8371: Indent = 'Suspend' / 'Resume' / [ IndentSign ] IndentValue .
1.10 cvs 8372: IndentSign = '+' / '-' .
8373: IndentValue = NUMBER .
1.1 cvs 8374:
8375: Object = ConstID / CharString /
8376: BufferID /
8377: VarID /
1.30 cvs 8378: '(' Function < Function > ')' /
1.21 cvs 8379: [ 'Translated' ] AttrID /
1.1 cvs 8380: 'Value' /
8381: 'Content' /
8382: 'Attributes' /
8383: 'Presentation' /
8384: 'RefId' /
8385: 'PairId' /
8386: 'FileDir' / 'FileName' / 'Extension' /
8387: 'DocumentName' / 'DocumentDir' /
8388: [ 'Referred' ] ReferredObject .
8389: Position = 'After' / 'Before' .
8390:
1.6 cvs 8391: ReferredObject= VarID /
8392: ElemID [ ExtStruct ] /
8393: 'RefId' /
8394: 'DocumentName' / 'DocumentDir' .
1.1 cvs 8395:
1.6 cvs 8396: File = FileName / BufferID .
8397: FileName = STRING .
1.1 cvs 8398:
1.6 cvs 8399: RelPosition = 'Included' / 'Referred' .
8400: ExtStruct = '(' ElemID ')' .
1.1 cvs 8401:
1.6 cvs 8402: TrSchema = NAME .
8403:
1.30 cvs 8404: AttrSeq = TransAttr < TransAttr > .
1.6 cvs 8405: TransAttr = AttrID [ '(' ElemID ')' ]
8406: [ RelatAttr ] ':' RuleSeq .
8407:
1.30 cvs 8408: PresSeq = PresTrans < PresTrans > .
1.6 cvs 8409: PresTrans = PresRule ':' RuleSeq .
8410: PresRule = 'Size' [ PresRelation ] /
8411: 'Indent' [ PresRelation ] /
8412: 'LineSpacing' [ PresRelation ] /
8413: 'Adjust' [ '=' AdjustVal ] /
8414: 'Hyphenate' [ '=' BoolVal ] /
8415: 'Style' [ '=' StyleVal ] /
1.24 cvs 8416: 'Weight' [ '=' WeightVal ] /
1.6 cvs 8417: 'Font' [ '=' FontVal ] /
8418: 'UnderLine' [ '=' UnderLineVal ] /
8419: 'Thickness' [ '=' ThicknessVal ] /
8420: 'LineStyle' [ '=' LineStyleVal ] /
8421: 'LineWeight' [ PresRelation ] /
8422: 'FillPattern' [ '=' Pattern ] /
8423: 'Background' [ '=' Color ] /
8424: 'Foreground' [ '=' Color ] .
8425:
8426: PresRelation = '=' PresValue /
1.30 cvs 8427: '>' [ '-' ] PresMinimum /
1.6 cvs 8428: '<' [ '-' ] PresMaximum /
8429: 'IN' '[' [ '-' ] PresIntervalMin '..'
8430: [ '-' ] PresIntervalMax ']' .
1.35 cvs 8431: AdjustVal = 'Left' / 'Right' / 'VMiddle' / 'Justify' /
1.6 cvs 8432: 'LeftWithDots' .
8433: BoolVal = 'Yes' / 'No' .
1.24 cvs 8434: StyleVal = 'Roman' / 'Italics' / 'Oblique' .
8435: WeightVal = 'Normal' / 'Bold' .
1.6 cvs 8436: FontVal = 'Times' / 'Helvetica' / 'Courier' .
8437: UnderLineVal = 'NoUnderline' / 'UnderLined' /
8438: 'OverLined' / 'CrossedOut' .
8439: ThicknessVal = 'Thick' / 'Thin' .
8440: LineStyleVal = 'Solid' / 'Dashed' / 'Dotted' .
8441: Pattern = NAME .
8442: Color = NAME .
8443: PresMinimum = NUMBER .
8444: PresMaximum = NUMBER .
1.1 cvs 8445: PresIntervalMin= NUMBER .
8446: PresIntervalMax= NUMBER .
1.6 cvs 8447: PresValue = [ '-' ] PresVal .
8448: PresVal = NUMBER .
1.1 cvs 8449:
1.6 cvs 8450: TextTransSeq = [ Alphabet ] TransSeq .
8451: Alphabet = NAME .
1.30 cvs 8452: TransSeq = 'BEGIN' < Translation > 'END' ';' /
1.6 cvs 8453: Translation .
1.30 cvs 8454: Translation = Source [ '->' Target ] ';' .
1.6 cvs 8455: Source = STRING .
1.18 cvs 8456: Target = STRING .</pre>
8457: </div>
8458: <hr>
8459: </div>
1.1 cvs 8460:
1.18 cvs 8461: <div class="chapter">
8462: <h1><a name="sect7">Character coding</a></h1>
1.1 cvs 8463:
1.18 cvs 8464: <div class="section">
1.30 cvs 8465: <h2><a name="sectb71">Characters</a></h2>
1.1 cvs 8466:
1.30 cvs 8467: <p>The characters of the Latin alphabet follow the encoding defined in the ISO
1.5 cvs 8468: 8859-1 (ISO Latin-1) standard. The characters of the Greek alphabet follow
1.18 cvs 8469: the encoding defined by Adobe for its Symbol font (Adobe FontSpecific).</p>
1.30 cvs 8470:
8471: <p>Characters whose octal code is greater than 0200 are written in the form of
1.1 cvs 8472: their octal code preceded by a backslash character (``\''). For example, the
1.30 cvs 8473: French word 'Résumé' is written <tt>R\351sum\351</tt>.</p>
8474:
8475: <p>To the ISO 8859-1 encoding four characters with the following codes have
8476: been added:<br>
1.18 cvs 8477: <tt>212</tt>: line break<br>
8478: <tt>240</tt>: sticky space<br>
8479: <tt>201</tt>: thin space<br>
8480: <tt>202</tt>: en space</p>
1.30 cvs 8481:
8482: <p>The <tt>212</tt> character is a ``line break'' character which forces a
8483: line break. The <tt>240</tt> character is a ``sticky space'', which cannot be
1.18 cvs 8484: replaced by a line break.</p>
8485: </div>
1.1 cvs 8486:
1.18 cvs 8487: <div class="section">
1.30 cvs 8488: <h2><a name="sectb72">Symbols</a></h2>
1.1 cvs 8489:
1.30 cvs 8490: <p>The table below gives the codes for the symbols of Thot. Symbols can be
8491: used in presentation schemas constants and in transcoding rules of translation
1.18 cvs 8492: schemas. Each symbol is represented by a single character.</p>
8493: <ul>
1.30 cvs 8494: <li><tt>r</tt>: a radical</li>
8495: <li><tt>i</tt>: a simple integral</li>
8496: <li><tt>c</tt>: a curvilinear integral</li>
8497: <li><tt>d</tt>: a double integral</li>
8498: <li><tt>t</tt>: a triple integral</li>
8499: <li><tt>S</tt>: the summation symbol</li>
8500: <li><tt>P</tt>: the product symbol</li>
8501: <li><tt>U</tt>: the union symbol</li>
8502: <li><tt>I</tt>: the intersection symbol</li>
8503: <li><tt>></tt>: a right arrow</li>
8504: <li><tt><</tt>: a left arrow</li>
8505: <li><tt>^</tt>: an up arrow</li>
8506: <li><tt>V</tt>: a down arrow</li>
8507: <li><tt>(</tt>: an opening parenthesis</li>
8508: <li><tt>)</tt>: a closing parenthesis</li>
8509: <li><tt>{</tt>: an opening brace</li>
8510: <li><tt>}</tt>: a closing brace</li>
8511: <li><tt>[</tt>: an opening bracket</li>
8512: <li><tt>]</tt>: a closing bracket</li>
1.18 cvs 8513: </ul>
8514: </div>
1.1 cvs 8515:
1.18 cvs 8516: <div class="section">
1.30 cvs 8517: <h2><a name="sectb73">Graphical elements</a></h2>
1.1 cvs 8518:
1.30 cvs 8519: <p>The table below gives the codes for the graphical elements of Thot. These
1.1 cvs 8520: elements can be used in presentation schemas constants and in transcoding
8521: rules of translation schemas. Each graphical element is represented by a
1.18 cvs 8522: single character.</p>
8523: <ul>
1.30 cvs 8524: <li>a: a circle</li>
8525: <li><p><tt>A</tt>: an open curve with an arrow head at the end</p>
8526: </li>
8527: <li><tt>b</tt>: a horizontal line along the lower side of the box</li>
8528: <li><tt>B</tt>: an open curve</li>
8529: <li><tt>c</tt>: an ellipse inscribed in the box</li>
8530: <li><tt>C</tt>: a rectangle with rounded corners</li>
8531: <li><tt>D</tt>: an open curve with two arrow heads</li>
8532: <li><tt>e</tt>: The northwest/southeast diagonal of the box with an
8533: arrowhead at the bottom</li>
8534: <li><tt>E</tt>: The southwest/northeast diagonal of the box with an
8535: arrowhead at the top</li>
8536: <li><tt>F</tt>: an open curve with an arrow head at start</li>
8537: <li><tt>g</tt>: a line from the origin of the box to its opposite
8538: corner</li>
8539: <li><tt>h</tt>: a horizontal line as wide as the box and placed in its
8540: middle</li>
8541: <li><tt>l</tt>: a vertical line on the left side of the box</li>
8542: <li><tt>L</tt>: a lozenge</li>
8543: <li><tt>M</tt>: an open broken line with two arrow heads</li>
8544: <li><tt>N</tt>: an open broken line with an arrow head at start</li>
8545: <li><tt>o</tt>: The southwest/northeast diagonal of the box with an
8546: arrowhead at the bottom</li>
8547: <li><tt>O</tt>: The northwest/southeast diagonal of the box with an
8548: arrowhead at the top</li>
8549: <li><tt>p</tt>: a polygon</li>
8550: <li><tt>P</tt>: a rectangle with round corners and a horizontal bar at the
8551: top</li>
8552: <li><tt>Q</tt>: an ellipse with a horizontal bar at the top</li>
8553: <li><tt>r</tt>: a vertical line on the right side of the box</li>
8554: <li><tt>R</tt>: a rectangle which is the shape of the box</li>
8555: <li><tt>s</tt>: a closed curve</li>
8556: <li><tt>S</tt>: an open broken line</li>
8557: <li><tt>t</tt>: a horizontal line along the upper side of the box</li>
8558: <li><tt>U</tt>: an open broken line with an arrow head at the end</li>
8559: <li><tt>v</tt>: a vertical line as tall as the box and placed in its
8560: middle</li>
8561: <li><tt>V</tt>: a down arrow as tall as the box and in its middle</li>
8562: <li>w: a segment (2 points)</li>
8563: <li><tt>W</tt>: the upper right corner</li>
8564: <li>x: a segment (2 points) with an arrow head at the end</li>
8565: <li><tt>X</tt>: the lower right corner</li>
8566: <li>y: a segment (2 points) with an arrow head at the end</li>
8567: <li><tt>Y</tt>: the lower left corner</li>
8568: <li>z: a segment (2 points) with an arrow head at the end</li>
8569: <li><tt>Z</tt>: the upper left corner</li>
8570: <li><tt>space</tt>: a transparent element</li>
8571: <li><tt>^</tt>: an up arrow as tall as the box and in its middle</li>
8572: <li><tt>></tt>: a right arrow as long as the box's width and in its
8573: middle</li>
8574: <li><tt>></tt>: a left arrow as long as the box's width and in its
8575: middle</li>
8576: <li><tt>/</tt>: The southwest/northeast diagonal of the box</li>
8577: <li><tt>\</tt>: the northwest/southeast diagonal of the box</li>
1.18 cvs 8578: </ul>
8579: <hr>
8580: </div>
8581: </div>
8582: </body>
8583: </html>
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