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1.30 cvs 5: <title>The Languages of Thot</title>
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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:
1.34 ! cvs 18: <h4>Version of December 28, 2000</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="#sectd42224">Justification</a></small></li>
167: <li><small><a href="#sectd42225">Hyphenation</a></small></li>
168: <li><small><a href="#sectd42226">Avoiding line
169: breaking</a></small></li>
170: </ul>
171: </li>
172: <li><a href="#sectc4223">Page breaking and line breaking
173: conditions</a></li>
174: <li><a href="#sectc4224">Visibility</a></li>
1.34 ! cvs 175: <li><a href="#sectc4225">Character style properties</a>
1.30 cvs 176: <ul>
177: <li><small><a href="#sectd42251">Character size</a></small></li>
178: <li><small><a href="#sectd42252">Font and character
179: style</a></small></li>
180: <li><small><a href="#sectd42253">Underlining</a></small></li>
181: </ul>
182: </li>
183: <li><a href="#sectc4226">Stacking order</a></li>
184: <li><a href="#sectc4227">Line style</a></li>
185: <li><a href="#sectc4228">Line thickness</a></li>
186: <li><a href="#sectc4229">Fill pattern</a></li>
187: <li><a href="#sectc4230">Colors</a></li>
188: <li><a href="#sectc4230a">Background color and border</a></li>
189: <li><a href="#sectc4230b">Background pictures</a></li>
190: <li><a href="#sectc4231">Presentation box content</a></li>
191: <li><a href="#sectc4232">Presentation box creation</a></li>
192: <li><a href="#sectc4233">Page layout</a></li>
193: <li><a href="#sectc4234">Box copies</a></li>
194: </ul>
195: </li>
196: </ul>
197: </li>
198: <li><big><a href="#sect5">The T language</a></big>
199: <ul>
200: <li><strong><a href="#sectb51">Document translation</a></strong>
201: <ul>
202: <li><a href="#sectc511">Translation principles</a></li>
203: <li><a href="#sectc512">Translation procedure</a></li>
204: </ul>
205: </li>
206: <li><strong><a href="#sectb52">Translation definition
207: language</a></strong>
208: <ul>
209: <li><a href="#sectc521">Organization of a translation
210: schema</a></li>
211: <li><a href="#sectc522">Line length</a></li>
212: <li><a href="#sectc523">Buffers</a></li>
213: <li><a href="#sectc524">Counters</a></li>
214: <li><a href="#sectc525">Constants</a></li>
215: <li><a href="#sectc526">Variables</a></li>
216: <li><a href="#sectc527">Translating structure elements</a></li>
217: <li><a href="#sectc528">Conditional rules</a>
218: <ul>
219: <li><small><a href="#sectd5281">Conditions based on the logical
220: position of the element</a></small></li>
221: <li><small><a href="#sectd5282">Conditions on
222: references</a></small></li>
223: <li><small><a href="#sectd5284">Conditions on the
224: alphabets</a></small></li>
225: <li><small><a href="#sectd5285">Conditions on page
226: breaks</a></small></li>
227: <li><small><a href="#sectd5286">Conditions on the element's
228: content</a></small></li>
229: <li><small><a href="#sectd5288">Conditions on the presence of
230: specific presentation rules</a></small></li>
231: <li><small><a href="#sectd5289">Conditions on the presence of
232: logical attributes</a></small></li>
233: <li><small><a href="#sectd52810">Conditions on logical
234: attributes</a></small></li>
235: <li><small><a href="#sectd52811">Conditions on specific
236: presentation rules</a></small></li>
237: </ul>
238: </li>
239: <li><a href="#sectc529">Translation rules</a></li>
240: <li><a href="#sectc5210">The <tt>Create</tt> rule</a></li>
241: <li><a href="#sectc5211">The <tt>Write</tt> rule</a></li>
242: <li><a href="#sectc5212">The <tt>Read</tt> rule</a></li>
243: <li><a href="#sectc5213">The <tt>Include</tt> rule</a></li>
244: <li><a href="#sectc5214">The <tt>Get</tt> rule</a></li>
245: <li><a href="#sectc5215">The <tt>Copy</tt> rule</a></li>
246: <li><a href="#sectc5216">The <tt>Use</tt> rule</a></li>
247: <li><a href="#sectc5217">The <tt>Remove</tt> rule</a></li>
1.31 cvs 248: <li><a href="#sectc5217a">The <code>Ignore</code> rule</a></li>
1.30 cvs 249: <li><a href="#sectc5218">The <tt>NoTranslation</tt> rule</a></li>
250: <li><a href="#sectc5219">The <tt>NoLineBreak</tt> rule</a></li>
251: <li><a href="#sectc5220">The <tt>ChangeMainFile</tt> rule</a></li>
252: <li><a href="#sectc5220a">The <tt>RemoveFile</tt> rule</a></li>
253: <li><a href="#sectc5221">The <tt>Set</tt> and <tt>Add</tt>
254: rules</a></li>
255: <li><a href="#sectc5221a">The <tt>Indent</tt> rule</a></li>
256: <li><a href="#sectc5222">Rule application order</a></li>
257: <li><a href="#sectc5223">Translation of logical attributes</a></li>
258: <li><a href="#sectc5224">Translation of specific
259: presentations</a></li>
260: <li><a href="#sectc5225">Recoding of characters, symbols and
261: graphics</a></li>
262: </ul>
263: </li>
264: </ul>
265: </li>
266: <li><big><a href="#sect6">Language grammars</a></big>
267: <ul>
268: <li><strong><a href="#sectb61">The M meta-language</a></strong></li>
269: <li><strong><a href="#sectb62">The S language</a></strong></li>
270: <li><strong><a href="#sectb63">The P language</a></strong></li>
271: <li><strong><a href="#sectb64">The T language</a></strong></li>
272: </ul>
273: </li>
274: <li><big><a href="#sect7">Character coding</a></big>
275: <ul>
276: <li><strong><a href="#sectb71">Characters</a></strong></li>
277: <li><strong><a href="#sectb72">Symbols</a></strong></li>
278: <li><strong><a href="#sectb73">Graphical elements</a></strong></li>
279: </ul>
280: </li>
1.18 cvs 281: </ul>
282: <hr>
283: </div>
1.1 cvs 284:
1.18 cvs 285: <div class="chapter">
1.30 cvs 286: <h1><a name="sect2">The document model of Thot</a></h1>
1.1 cvs 287:
1.30 cvs 288: <p>All of the services which Thot provides to the user are based on the
289: system's internal document representation. This representation is itself
290: derived from the document model which underlies Thot. The model is presented
291: here, prior to the description of the languages which permit the generic
292: specification of documents.</p>
1.1 cvs 293:
1.18 cvs 294: <div class="section">
1.30 cvs 295: <h2><a name="sectb21">The logical structure of documents</a></h2>
1.1 cvs 296:
1.30 cvs 297: <p>The document model of Thot is primarily designed to allow the user to
298: operate on those entities which s/he has in mind when s/he works on a
299: document. The model makes no assumptions about the nature of these entities.
300: It is essentially these logical entities, such as paragraphs, sections,
301: chapters, notes, titles, and cross-references which give a document its
302: logical structure.</p>
303:
304: <p>Because of this model, the author can divide the document into chapters,
1.1 cvs 305: giving each one a title. The content of these chapters can be further divided
1.2 cvs 306: into sections, subsections, etc. The text is organized into successive
307: paragraphs, according to the content. In the writing phase, the lines, pages,
308: margins, spacing, fonts, and character styles are not very important. In fact,
309: if the system requires documents to be written in these terms, it gets in the
310: way. So, Thot's model is primarily based on the logical aspect of documents.
1.18 cvs 311: The creation of a model of this type essentially requires the definition :</p>
312: <ul>
1.30 cvs 313: <li>of the entities which can appear in the documents,</li>
314: <li>and the relations between these entities.</li>
1.18 cvs 315: </ul>
1.30 cvs 316:
317: <p>The choice of entities to include in the model can be subtle. Some
318: documents require chapters, while others only need various levels of sections.
319: Certain documents contain appendices, others don't. In different documents
320: the same logical entity may go by different names (e.g. ``Conclusion'' and
1.1 cvs 321: ``Summary''). Certain entities which are absolutely necessary in some
322: documents, such as clauses in a contract or the address of the recipient in a
1.18 cvs 323: letter, are useless in most other cases.</p>
1.30 cvs 324:
325: <p>The differences between documents result from more than just the entities
326: that appear in them, but also from the relationships between these entities
327: and the ways that they are linked. In certain documents, notes are spread
328: throughout the document, for example at the bottom of the page containing the
1.1 cvs 329: cross-reference to them, while in other documents they are collected at the
330: end of each chapter or even at the end of the work. As another example, the
331: introduction of some documents can contain many sections, while in other
332: documents, the introduction is restricted to be a short sequence of
1.18 cvs 333: paragraphs.</p>
1.30 cvs 334:
335: <p>All of this makes it unlikely that a single model can describe any document
336: at a relatively high level. It is obviously tempting to make up a list of
337: widely used entities, such as chapters, sections, paragraphs, and titles, and
338: then map all other entities onto the available choices. In this way, an
1.1 cvs 339: introduction can be supported as a chapter and a contract clause supported as
340: a paragraph or section. However, in trying to widen the range of usage of
341: certain entities, their meaning can be lost and the power of the model
342: reduced. In addition, while this widening partially solves the problem of
343: choosing entities, it does not solve the problem of their organization: when a
344: chapter must be composed of sections, how does one indicate that an
345: introduction has none when it is merely another chapter? One solution is to
346: include introductions in the list of supported entities. But then, how does
347: one distinguish those introductions which are allowed to have sections from
348: those which are not. Perhaps this could be done by defining two types of
349: introduction. Clearly, this approach risks an infinite expansion of the list
1.18 cvs 350: of widely used entities.</p>
351: </div>
1.1 cvs 352:
1.18 cvs 353: <div class="section">
1.30 cvs 354: <h2><a name="sectb22">Generic and specific structures</a></h2>
1.1 cvs 355:
1.30 cvs 356: <p>Thus, it is apparently impossible to construct an exhaustive inventory of
357: all those entities which are necessary and sufficient to precisely describe
358: any document. It also seems impossible to specify all possible arrangements of
1.18 cvs 359: these entities in a document. This is why Thot uses a <em>meta-model</em>
360: instead, which permits the description of numerous <em>models</em>, each one
361: describing a <em>class</em> of documents.</p>
1.30 cvs 362:
363: <p>A <em>class</em> is a set of documents having very similar structure. Thus,
1.1 cvs 364: the collection of research reports published by a laboratory constitutes a
365: class; the set of commercial proposals by the sales department of a company
366: constitutes another class; the set of articles published by a journal
367: constitutes a third class. Clearly, it is not possible to enumerate every
368: possible document class. It is also clear that new document classes must be
1.18 cvs 369: created to satisfy new needs and applications.</p>
1.30 cvs 370:
371: <p>To give a more rigorous definition of classes, we must introduce the ideas
372: of <em>generic structure</em> and <em>specific structure</em>. Each document
373: has a <em>specific structure</em> which organizes the various parts which
374: comprise it. We illustrate this with the help of a simple example comparing
375: two reports, A and B (<a href="#specstruct">see Figure</a>). The report A
376: contains an introduction followed by three chapters and a conclusion. The
377: first chapter contains two sections, the second, three sections. That is the
1.18 cvs 378: <em>specific</em> structure of document A. Similarly, the structure of
1.1 cvs 379: document B is: an introduction, two chapters, a conclusion; Chapter 1 has
380: three sections while Chapter 2 has four. The specific structures of these two
1.18 cvs 381: documents are thus different.</p>
1.1 cvs 382:
1.18 cvs 383: <div class="figure">
384: <hr>
385: <pre> Report A Report B
1.1 cvs 386: Introduction Introduction
387: Chapter 1 Chapter 1
388: Section 1.1 Section 1.1
389: Section 1.2 Section 1.2
390: Chapter 2 Section 1.3
391: Section 2.1 Chapter 2
392: Section 2.2 Section 2.1
393: Section 2.3 Section 2.2
394: Chapter 3 Section 2.3
395: Conclusion Section 2.4
1.18 cvs 396: Conclusion</pre>
1.30 cvs 397:
398: <p align="center"><em><a name="specstruct">Two specific
399: structures</a></em></p>
1.18 cvs 400: <hr>
1.30 cvs 401: </div>
402:
403: <p>The <em>generic structure</em> defines the ways in which specific
404: structures can be constructed. It specifies how to generate specific
405: structures. The reports A and B, though different, are constructed in
406: accordance with the same generic structure, which specifies that a report
407: contains an introduction followed by a variable number of chapters and a
408: conclusion, with each chapter containing a variable number of sections.</p>
409:
410: <p>There is a one-to-one correspondence between a class and a generic
411: structure: all the documents of a class are constructed in accordance with the
412: same generic structure. Hence the definition of the class: a class is a set
413: of documents whose specific structure is constructed in accordance with the
414: same generic structure. A class is characterized by its generic
415: structure.</p>
1.19 cvs 416:
1.30 cvs 417: <p>Thus, a generic structure can be considered to be a model at the level
418: which interests us, but only for one class of documents. When the definition
419: is limited to a single class of documents, it is possible to define a model
420: which does a good job of representing the documents of the class, including
421: the necessary entities and unencumbered by useless entities. The description
422: of the organization of the documents in the class can then be sufficiently
1.18 cvs 423: precise.</p>
424: </div>
1.1 cvs 425:
1.18 cvs 426: <div class="section">
1.30 cvs 427: <h2><a name="sectb23">Logical structure and physical structure</a></h2>
1.1 cvs 428:
1.30 cvs 429: <p>Generic structures only describe the <em>logical</em> organization of
1.18 cvs 430: documents, not their <em>physical</em> presentation on a screen or on sheets
1.1 cvs 431: of paper. However, for a document to be displayed or printed, its graphic
1.18 cvs 432: presentation must be taken into account.</p>
1.30 cvs 433:
434: <p>An examination of current printed documents shows that the details of
1.1 cvs 435: presentation essentially serve to bring out their logical structure. Outside
436: of some particular domains, notably advertising, the presentation is rarely
437: independent of the logical organization of the text. Moreover, the art of
438: typography consists of enhancing the organization of the text being set,
439: without catching the eye of the reader with overly pronounced effects. Thus,
440: italic and boldface type are used to emphasize words or expressions which have
441: greater significance than the rest of the text: keywords, new ideas,
442: citations, book titles, etc. Other effects highlight the organization of the
443: text: vertical space, margin changes, page breaks, centering, eventually
444: combined with the changes in the shapes or weight of the characters. These
445: effects serve to indicate the transitions between paragraphs, sections, or
446: chapters: an object's level in the logical structure of the document is shown
1.18 cvs 447: by the markedness of the effects.</p>
1.30 cvs 448:
449: <p>Since the model permits the description of all of the logical structure of
450: the document, the presentation can be derived from the model without being
1.1 cvs 451: submerged in the document itself. It suffices to use the logical structure of
452: the document to make the desired changes in its presentation: changes in type
1.18 cvs 453: size, type style, spacing, margin, centering, etc.</p>
1.30 cvs 454:
455: <p>Just as one cannot define a unique generic logical structure for all
456: document classes, one cannot define universal presentation rules which can be
457: applied to all document classes. For certain types of documents the chapter
458: titles will be centered on the page and printed in large, bold type. For
459: other documents, the same chapter titles will be printed in small, italic type
460: and aligned on the left margin.</p>
461:
462: <p>Therefore, it is necessary to base the presentation specifications for
1.1 cvs 463: documents on their class. Such a specification can be very fine-grained,
464: because the presentation is expressed in terms of the entities defined in the
465: generic logical structure of the class. Thus, it is possible to specify a
466: different presentation for the chapter titles and the section titles, and
467: similarly to specify titles for the sections according to their level in the
468: section hierarchy. The set of rules which specify the presentation of all the
1.18 cvs 469: elements defined in a generic logical structure is called a <em>generic
470: presentation</em>.</p>
1.30 cvs 471:
472: <p>There are several advantages derived from having a presentation linked to
473: the generic structure and described by a generic presentation. Homogeneity is
474: the first. Since every document in a class corresponds to the same generic
1.1 cvs 475: logical structure, a homogenous presentation for different documents of the
476: same class can be assured by applying the same generic presentation to all
477: documents of the class. Homogeneity of presentation can also be found among
1.2 cvs 478: the entities of a single document: every section heading will be presented in
1.1 cvs 479: the same way, the first line of every paragraph of the same type will have the
1.18 cvs 480: same indentation, etc.</p>
1.30 cvs 481:
482: <p>Another advantage of this approach to presentation is that it facilitates
1.1 cvs 483: changes to the graphical aspect of documents. A change to the generic
484: presentation rules attached to each type of entity will alter the presentation
485: of the entire document, and will do so homogenously. In this case, the
486: internal homogeneity of the class is no longer assured, but the way to control
487: it is simple. It suffices to adopt a single generic presentation for the
1.18 cvs 488: entire class.</p>
1.30 cvs 489:
490: <p>If the presentation of the class does not have to be homogenous, then the
1.1 cvs 491: appearance of the document can be adapted to the way it will be used or to the
492: device used to render it. This quality is sufficient to allow the existence
1.18 cvs 493: of <a name="mulpres">many generic presentations</a> for the same document
1.1 cvs 494: class. By applying one or the other of these presentations to it, the document
495: can be seen under different graphical aspects. It must be emphasized that
496: this type of modification of the presentation is not a change to the document
497: itself (in its specific logical structure or its content), but only in its
1.18 cvs 498: appearance at the time of editing or printing.</p>
499: </div>
1.1 cvs 500:
1.18 cvs 501: <div class="section">
1.30 cvs 502: <h2><a name="sectb24">Document structures and object structures</a></h2>
1.1 cvs 503:
1.30 cvs 504: <p>So far, we have only discussed the global structure of documents and have
505: not considered the contents found in that structure. We could limit ourselves
506: to purely textual contents by assuming that a title or a paragraph contains a
1.1 cvs 507: simple linear text. But this model would be too restrictive. In fact,
508: certain documents contain not only text, but also contain tables, diagrams,
509: photographs, mathematical formulas, and program fragments. The model must
1.18 cvs 510: permit the representation of such <em>objects</em>.</p>
1.30 cvs 511:
512: <p>Just as with the whole of the document, the model takes into account the
1.1 cvs 513: logical structure of objects of this type. Some are clearly structured,
514: others are less so. Logical structure can be recognized in mathematical
515: formulas, in tables, and in certain types of diagrams. On the other hand, it
516: is difficult to define the structure of a photograph or of some drawings. But
517: in any case, it does not seem possible to define one unique structure which
518: can represent every one of these types of objects. The approach taken in the
519: definition of meta-structure and document classes also applies to objects.
520: Object classes can be defined which put together objects of similar type,
1.18 cvs 521: constructed from the same generic logical structure.</p>
1.30 cvs 522:
523: <p>Thus, a mathematical class can be defined and have a generic logical
524: structure associated with it. But even if a single generic structure can
525: represent a sufficient variety of mathematical formulas, for other objects
526: with less rigorous structure, multiple classes must be defined. As for
527: documents, using multiple classes assures that the model can describe the full
528: range of objects to be presented. It also permits the system to support
529: objects which were not initially anticipated. Moreover, this comment applies
530: equally to mathematics: different classes of formulas can be described
531: depending on the domain of mathematics being described.</p>
532:
533: <p>Since objects have the same level of logical representation as documents,
534: they gain the same advantages. In particular, it is possible to define the
1.1 cvs 535: presentation separately from the objects themselves and attach it to the
536: class. Thus, as for documents, objects of the same type have a uniform
537: presentation and the presentation of every object in a given class can be
538: changed simply by changing the generic presentation of the class. Another
539: advantage of using this document model is that the system does not bother the
540: user with the details of presentation, but rather allows the user to
1.18 cvs 541: concentrate on the logical aspect of the document and the objects.</p>
1.30 cvs 542:
543: <p>It is clear that the documents in a class do not necessarily use the same
1.1 cvs 544: classes of objects: one technical report will contain tables while another
545: report will have no tables but will use mathematical formulas. The usable
1.2 cvs 546: object classes are not always mentioned in a limiting way in the generic
547: logical structure of documents. Rather, they can be chosen freely from a
1.18 cvs 548: large set, independent of the document class.</p>
1.30 cvs 549:
550: <p>Thus, the object classes will be made commonplace and usable in every
1.1 cvs 551: document. The notion of ``object'' can be enlarged to include not only
552: non-textual elements, but also certain types of textual elements which can
553: appear in practically every document, whatever their class. Among these
1.2 cvs 554: textual elements, one can mention enumerations, descriptions, examples,
1.18 cvs 555: quotations, even paragraphs.</p>
1.30 cvs 556:
557: <p>Thus, the document model is not a single, general model describing every
558: type of document in one place. Rather, it is a meta-model which can be used
559: to describe many different models each of which represents either a class of
1.1 cvs 560: similar documents or a class of similar objects which every document can
1.18 cvs 561: include.</p>
562: </div>
563: <hr>
564: </div>
1.1 cvs 565:
1.18 cvs 566: <div class="chapter">
567: <h1><a name="sect3">The S language</a></h1>
1.1 cvs 568:
1.18 cvs 569: <div class="section">
1.30 cvs 570: <h2><a name="sectb31">Document meta-structure</a></h2>
1.1 cvs 571:
1.30 cvs 572: <p>Since the concept of meta-structure is well suited to the task of
573: describing documents at a high level of abstraction, this meta-structure must
574: be precisely defined. Toward that end this section first presents the basic
1.1 cvs 575: elements from which documents and structured objects are composed and then
576: specifies the ways in which these basic elements are assembled into structures
1.18 cvs 577: representing complete documents and objects.</p>
1.1 cvs 578:
1.18 cvs 579: <div class="subsection">
1.30 cvs 580: <h3><a name="sectc311">The basic types</a></h3>
1.1 cvs 581:
1.30 cvs 582: <p>At the lowest level of a document's structure, the first atom considered is
1.1 cvs 583: the character. However, since characters are seldom isolated, usually
584: appearing as part of a linear sequence, and in order to reduce the complexity
1.18 cvs 585: of the document structure, <em>character strings</em> are used as atoms and
1.1 cvs 586: consecutive characters belonging to the same structural element are grouped in
1.18 cvs 587: the same character string.</p>
1.30 cvs 588:
589: <p>If the structure of a document is not refined to go down to the level of
1.1 cvs 590: words or phrases, the contents of a simple paragraph can be considered to be a
591: single character string. On the other hand, the title of a chapter, the title
592: of the first section of that chapter, and the text of the first paragraph of
593: that section constitute three different character strings, because they belong
1.18 cvs 594: to distinct structural elements.</p>
1.30 cvs 595:
596: <p>If, instead, a very fine-grained representation for the structure of a
1.1 cvs 597: document is sought, character strings could be defined to contain only a
598: single word, or even just a single character. This is the case, for example,
599: in programs, for which one wants to retain a structure very close to the
1.2 cvs 600: syntax of the programming language. In this case, an assignment statement
1.1 cvs 601: initializing a simple variable to zero would be composed of two structural
602: elements, the identifier of the variable (a short character string) and the
1.18 cvs 603: assigned value (a string of a single character, `0').</p>
1.30 cvs 604:
605: <p>The character string is not the only atom necessary for representing those
1.1 cvs 606: documents that interest us. It suffices for purely textual documents, but as
607: soon as the non-textual objects which we have considered arise, there must be
608: other atoms; the number of objects which are to be represented determines the
1.18 cvs 609: number of types of atoms that are necessary.</p>
1.30 cvs 610:
611: <p>Primitive <em>graphical elements</em> are used for tables and figures of
1.1 cvs 612: different types. These elements are simple geometric shapes like horizontal
613: or vertical lines, which are sufficient for tables, or even oblique lines,
1.2 cvs 614: arrows, rectangles, circles, polygons, and curves for use in figures. From
615: these elements and character strings, graphical objects and tables can be
1.18 cvs 616: constructed.</p>
1.30 cvs 617:
618: <p>Photographs, though having very little structure, must still appear in
1.18 cvs 619: documents. They are supported by <em>picture</em> elements, which are
620: represented as matrices of pixels.</p>
1.30 cvs 621:
622: <p>Finally, mathematical notations require certain elements which are
1.18 cvs 623: simultaneously characters and graphical elements, the <em>symbols</em>. By way
1.2 cvs 624: of example, radicals, integration signs, or even large parentheses are
1.1 cvs 625: examples of this type of atom. The size of each of these symbols is
626: determined by its environment, that is to say, by the expression to which it
1.18 cvs 627: is attached.</p>
1.30 cvs 628:
629: <p>To summarize, the primitive elements which are used in the construction of
1.18 cvs 630: documents and structured objects are:</p>
631: <ul>
1.30 cvs 632: <li>character strings,</li>
633: <li>graphical elements,</li>
634: <li>pictures,</li>
635: <li>and mathematical symbols.</li>
1.18 cvs 636: </ul>
637: </div>
1.1 cvs 638:
1.18 cvs 639: <div class="subsection">
1.30 cvs 640: <h3><a name="sectc312">Constructed elements</a></h3>
641:
642: <p>A document is evidently formed from primitive elements. But the model of
643: Thot also proposes higher level elements. Thus, in a document composed of
644: several chapters, each chapter is an element, and in the chapters each section
645: is also an element, and so on. A document is thus an organized set of
646: elements.</p>
1.1 cvs 647:
1.30 cvs 648: <p>In a document there are different sorts of elements. Each element has a
1.18 cvs 649: <em>type</em> which indicates the role of the element within the document as a
1.1 cvs 650: whole. Thus, we have, for example, the chapter and section types. The
651: document is made up of typed elements: elements of the type chapter and
652: elements of the type section, among others, but also character string elements
653: and graphical elements: the primitive elements are typed elements just as
654: well. At the other extreme, the document itself is also considered to be a
1.18 cvs 655: typed element.</p>
1.30 cvs 656:
657: <p>The important difference between the primitive elements and the other
658: elements of the document is that the primitive elements are atoms (they cannot
659: be decomposed), whereas the others, called <em>constructed elements</em>, are
1.1 cvs 660: composed of other elements, which can either be primitive elements or
661: constructed elements. A constructed element of type chapter (or more simply,
662: ``a chapter'') is composed of sections, which are also constructed elements. A
663: paragraph, a constructed element, can be made up of character strings, which
1.18 cvs 664: are primitive elements, and of equations, which are constructed elements.</p>
1.30 cvs 665:
666: <p>A document is also a constructed element. This is an important point. In
1.1 cvs 667: particular, it allows a document to be treated as part of another document,
668: and conversely, permits a part of a document to be treated as a complete
669: document. Thus, an article presented in a journal is treated by its author as
670: a document in itself, while the editor of the journal considers it to be part
671: of an issue. A table or a figure appearing in a document can be extracted and
672: treated as a complete document, for example to prepare transparencies for a
1.18 cvs 673: conference.</p>
1.30 cvs 674:
675: <p>These thoughts about types and constructed elements apply just as well to
1.1 cvs 676: objects as they do to documents. A table is a constructed element made up of
677: other constructed elements, rows and columns. A row is formed of cells, which
678: are also constructed elements which contain primitive elements (character
1.18 cvs 679: strings) and/or constructed elements like equations.</p>
680: </div>
1.1 cvs 681:
1.18 cvs 682: <div class="subsection">
1.30 cvs 683: <h3><a name="sectc313">Logical structure constructors</a></h3>
1.1 cvs 684:
1.30 cvs 685: <p>Having defined the primitive elements and the constructed elements, it is
686: now time to define the types of organization which allow the building of
1.18 cvs 687: structures. For this, we rely on the notion of the <em>constructor</em>. A
1.1 cvs 688: constructor defines a way of assembling certain elements in a structure. It
689: resides at the level of the meta-structure: it does not describe the existing
690: relations in a given structure, but rather defines how elements are assembled
1.18 cvs 691: to build a structure that conforms to a model.</p>
1.30 cvs 692:
693: <p>In defining the overall organization of documents, the first two
694: constructors considered are the aggregate and the list.</p>
1.1 cvs 695:
1.18 cvs 696: <div class="subsubsection">
1.30 cvs 697: <h4><a name="sectd3131">Aggregate and List</a></h4>
1.1 cvs 698:
1.30 cvs 699: <p>The <em>aggregate</em> constructor is used to define constructed element
700: types which are collections of a given number of other elements. These
701: collections may or may not be ordered. The elements may be either constructed
702: or primitive and are specified by their type. A report (that is, a
703: constructed element of the report type) has an aggregate structure. It is
704: formed from a title, an author's name, an introduction, a body, and a
705: conclusion, making it a collection of five element types. This type of
706: constructor is found in practically every document, and generally at several
707: levels in a document.</p>
708:
709: <p>The <em>list</em> constructor is used to define constructed elements which
710: are ordered sequences of elements (constructed or primitive) having the same
711: type. The minimum and maximum numbers of elements for the sequence can be
712: specified in the list constructor or the number of elements can be left
713: unconstrained. The body of a report is a list of chapters and is typically
714: required to contain a minimum of two chapters (is a chapter useful if it is
715: the only one in the report?) The chapter itself can contain a list of
716: sections, each section containing a list of paragraphs. In the same way as
717: the aggregate, the list is a very frequently used constructor in every type of
718: document. However, these two constructors are not sufficient to describe every
719: document structure; thus other constructors supplement them.</p>
1.18 cvs 720: </div>
1.1 cvs 721:
1.18 cvs 722: <div class="subsubsection">
1.30 cvs 723: <h4><a name="sectd3132">Choice, Schema, and Unit</a></h4>
1.1 cvs 724:
1.30 cvs 725: <p>The <em>choice</em> constructor is used to define the structure of an
726: element type for which one alternative is chosen from several possibilities.
727: Thus, a paragraph can be either a simple text paragraph, or an enumeration, or
728: a citation.</p>
729:
730: <p>The choice constructor indicates the complete list of possible options,
731: which can be too restrictive in certain cases, the paragraph being one such
732: case. Two constructors, <em>unit</em> and <em>schema</em>, address this
1.1 cvs 733: inconvenience. They allow more freedom in the choice of an element type. If
734: a paragraph is defined by a schema constructor, it is possible to put in the
735: place of a paragraph a table, an equation, a drawing or any other object
736: defined by another generic logical structure. It is also possible to define a
737: paragraph as a sequence of units, which could be character strings, symbols,
1.2 cvs 738: or pictures. The choice constructor alone defines a generic logical structure
1.1 cvs 739: that is relatively constrained; in contrast, using units and schemas, a very
1.18 cvs 740: open structure can be defined.</p>
1.30 cvs 741:
742: <p>The <em>schema</em> constructor represents an object defined by a generic
1.18 cvs 743: logical structure chosen freely from among those available.</p>
1.30 cvs 744:
745: <p>The <em>unit</em> constructor represents an element whose type can be
746: either a primitive type or an element type defined as a unit in the generic
747: logical structure of the document, or in another generic logical structure
748: used in the document. Such an element may be used in document objects
749: constructed according to other generic structures.</p>
750:
751: <p>Thus, for example, if a cross-reference to a footnote is defined in the
1.1 cvs 752: generic logical structure ``Article'' as a unit, a table (an object defined by
753: another generic structure) can contain cross-references to footnotes, when
754: they appear in an article. In another type of document, a table defined by
755: the same generic structure can contain other types of elements, depending on
756: the type of document into which the table is inserted. All that is needed is
757: to declare, in the generic structure for tables, that the contents of cells
758: are units. In this way, the generic structure of objects is divided up
759: between different types of documents which are able to adapt themselves to the
1.18 cvs 760: environment into which they are inserted.</p>
761: </div>
1.1 cvs 762:
1.18 cvs 763: <div class="subsubsection">
1.30 cvs 764: <h4><a name="sectd3133">Reference and Inclusion</a></h4>
1.1 cvs 765:
1.30 cvs 766: <p>The <em>reference</em> is used to define document elements that are
1.18 cvs 767: cross-references to other elements, such as a section, a chapter, a
768: bibliographic citation, or a figure. The reference is bi-directional. It can
769: be used to access both the element being cross-referenced and each of the
770: elements which make use of the cross-reference.</p>
1.30 cvs 771:
772: <p>References can be either <em>internal</em> or <em>external</em>. That is,
1.1 cvs 773: they can designate elements which appear in the same document or in another
1.18 cvs 774: document.</p>
1.30 cvs 775:
776: <p>The <em><a name="inclusion">inclusion</a></em> constructor is a special
777: type of reference. Like the reference, it is an internal or external
778: bidirectional link, but it is not a cross-reference. This link represents the
779: ``live'' inclusion of the designated element; it accesses the most recent
780: version of that element and not a ``dead'' copy, fixed in the state in which
781: it was found at the moment the copy was made. As soon as an element is
782: modified, all of its inclusions are automatically brought up to date. It must
783: be noted that, in addition to inclusion, Thot permits the creation of ``dead''
784: copies.</p>
785:
786: <p>There are three types of inclusions: inclusions with full expansion,
1.1 cvs 787: inclusions with partial expansion, and inclusions without expansion. During
788: editing, inclusions without expansion are represented on the screen by the
789: name of the included document, in a special color, while inclusions with
790: expansion (full or partial) are represented by a copy (full or partial) of the
791: included element (also in a special color). The on-screen representation of a
1.18 cvs 792: partial inclusion is a <a href="#sectc3213">``skeleton''</a> image of the
793: included document.</p>
1.30 cvs 794:
795: <p>Inclusion with complete expansion can be used to include parts of the same
1.1 cvs 796: document or of other documents. Thus, it can be either an internal or an
797: external link. It can be used to include certain bibliographic entries of a
798: scientific article in another article, or to copy part of a mathematical
799: formula into another formula of the same document, thus assuring that both
1.18 cvs 800: copies will remain synchronized.</p>
1.30 cvs 801:
802: <p>Inclusion without expansion or with partial expansion is used to include
1.1 cvs 803: complete documents. It is always an external link. It is used primarily to
804: divide very large documents into sub-documents that are easier to manipulate,
805: especially when there are many authors. So, a book can include some chapters,
806: where each chapter is a different document which can be edited separately.
807: When viewing the book on the screen, it might be desirable to see only the
808: titles of the chapters and sections. This can be achieved using inclusion
1.18 cvs 809: with partial expansion.</p>
1.30 cvs 810:
811: <p>During printing, inclusions without expansion or with partial expansion can
812: be represented either as they were shown on the screen or by a complete (and
1.18 cvs 813: up-to-date) copy of the included element or document.</p>
1.30 cvs 814:
815: <p>The inclusion constructor, whatever its type, respects the generic
816: structure: only those elements authorized by the generic structure can be
817: included at a given position in a document.</p>
1.18 cvs 818: </div>
1.1 cvs 819:
1.18 cvs 820: <div class="subsubsection">
1.30 cvs 821: <h4><a name="sectd3134">Mark pairs</a></h4>
1.1 cvs 822:
1.30 cvs 823: <p>It is often useful to delimit certain parts of a document independently
824: from the logical structure. For example, one might wish to attach some
825: information (in the form of an <a href="#sectc315">attribute</a>) or a
826: particular treatment to a group of words or a set of consecutive paragraphs.
827: <em>Mark pairs</em> are used to do this.</p>
828:
829: <p>Mark pairs are elements which are always paired and are terminals in the
1.1 cvs 830: logical structure of the document. Their position in the structure of the
831: document is defined in the generic structure. It is important to note that
1.18 cvs 832: when the terminals of a mark pair are <em>extensions</em> (see the next
833: section), they can be used quite freely.</p>
834: </div>
1.1 cvs 835:
1.18 cvs 836: <div class="subsubsection">
1.30 cvs 837: <h4><a name="sectd3135">Restrictions and Extensions</a></h4>
1.1 cvs 838:
1.30 cvs 839: <p>The primitive types and the constructors presented so far permit the
1.1 cvs 840: definition of the logical structure of documents and objects in a rigorous
841: way. But this definition can be very cumbersome in certain cases, notably
842: when trying to constrain or extend the authorized element types in a
1.18 cvs 843: particular context. <em>Restrictions</em> and <em>extensions</em> are used to
844: cope with these cases.</p>
1.30 cvs 845:
846: <p>A restriction associates with a particular element type <em>A</em>, a list
847: of those element types which elements of type <em>A</em> may not contain, even
848: if the definition of type <em>A</em> and those of its components authorize
849: them otherwise. This simplifies the writing of generic logical structures and
1.1 cvs 850: allows limitations to be placed, when necessary, on the choices offered by the
1.18 cvs 851: schema and unit constructors.</p>
1.30 cvs 852:
853: <p>Extensions are the inverse of restrictions. They identify a list of
854: element types whose presence <em>is</em> permitted, even if its definition and
855: those of its components do not authorize them otherwise.</p>
1.18 cvs 856: </div>
857:
858: <div class="subsubsection">
1.30 cvs 859: <h4><a name="sectd3136">Summary</a></h4>
1.18 cvs 860:
1.30 cvs 861: <p>Thus, four constructors are used to construct a document:</p>
1.18 cvs 862: <ul>
1.30 cvs 863: <li>the aggregate constructor (ordered or not),</li>
864: <li>the list constructor,</li>
865: <li>the choice constructor and its extensions, the unit and schema
866: constructors,</li>
867: <li>the reference constructor and its variant, the inclusion.</li>
868: </ul>
869:
870: <p>These constructors are also sufficient for objects. Thus, these
871: constructors provide a homogenous meta-model which can describe both the
872: organization of the document as a whole and that of the various types of
873: objects which it contains. After presenting the description language for
874: generic structures, we will present several examples which illustrate the
875: appropriateness of the model.</p>
876:
877: <p>The first three constructors (aggregate, list and choice) lead to tree-like
1.1 cvs 878: structures for documents and objects, the objects being simply the subtrees of
879: the tree of a document (or even of other objects' subtrees). The reference
880: constructor introduces other, non-hierarchical, relations which augment those
881: of the tree: when a paragraph makes reference to a chapter or a section, that
882: relation leaves the purely tree-like structure. Moreover, external reference
883: and inclusion constructors permit the establishment of links between different
1.18 cvs 884: documents, thus creating a hypertext structure.</p>
885: </div>
886: </div>
1.1 cvs 887:
1.18 cvs 888: <div class="subsection">
1.30 cvs 889: <h3><a name="sectc314">Associated Elements</a></h3>
1.1 cvs 890:
1.30 cvs 891: <p>Thanks to the list, aggregate and choice constructors, the organization of
892: the document is specified rigorously, using constructed and primitive
893: elements. But a document is made up of more than just its elements; it clearly
894: also contains links between them. There exist elements whose position in the
1.1 cvs 895: document's structure is not determinable. This is notably the case for
896: figures and notes. A figure can be designated at many points in the same
897: document and its place in the physical document can vary over the life of the
898: document without any effect on the meaning or clarity of the document. At one
899: time, it can be placed at the end of the document along with all other
900: figures. At another time, it can appear at the top of the page which follows
901: the first mention of the figure. The figures can be dispersed throughout the
902: document or can be grouped together. The situation is similar for notes,
903: which can be printed at the bottom of the page on which they are mentioned or
904: assembled together at the end of the chapter or even the end of the work. Of
905: course, this brings up questions of the physical position of elements in
906: documents that are broken into pages, but this reflects the structural
907: instability of these elements. They cannot be treated the same way as
908: elements like paragraphs or sections, whose position in the structure is
1.18 cvs 909: directly linked to the semantics of the document.</p>
1.30 cvs 910:
911: <p>Those elements whose position in the structure of the document is not
912: fixed, even though they are definitely part of the document, are called
1.18 cvs 913: <em>associated elements</em>. Associated elements are themselves structures,
1.1 cvs 914: which is to say that their content can be organized logically by the
1.18 cvs 915: constructors from primitive and constructed elements.</p>
1.30 cvs 916:
917: <p>It can happen that the associated elements are totally disconnected from
918: the structure of the document, as in a commentary or appraisal of the entire
919: work. But more often, the associated elements are linked to the content of the
1.1 cvs 920: document by references. This is generally the case for notes and figures,
1.18 cvs 921: among others.</p>
1.30 cvs 922:
923: <p>Thus, associated elements introduce a new use for the reference
924: constructor. It not only serves to create links between elements of the
925: principal structure of the document, but also serves to link the associated
926: elements to the primary structure.</p>
1.18 cvs 927: </div>
1.1 cvs 928:
1.18 cvs 929: <div class="subsection">
1.30 cvs 930: <h3><a name="sectc315">Attributes</a></h3>
1.1 cvs 931:
1.30 cvs 932: <p>There remain logical aspects of documents that are not entirely described
933: by the structure. Certain types of semantic information, which are not stated
1.1 cvs 934: explicitly in the text, must also be taken into account. In particular, such
935: information is shown by typographic effects which do not correspond to a
936: change between structural elements. In fact, certain titles are set in bold
937: or italic or are printed in a different typeface from the rest of the text in
938: order to mark them as structurally distinct. But these same effects
939: frequently appear in the middle of continuous text (e.g. in the interior of a
940: paragraph). In this case, there is no change between structural elements; the
941: effect serves to highlight a word, expression, or phrase. The notion of an
1.18 cvs 942: <em>attribute</em> is used to express this type of information.</p>
1.30 cvs 943:
944: <p>An attribute is a piece of information attached to a structural element
945: which augments the type of the element and clarifies its function in the
946: document. Keywords, foreign language words, and titles of other works can all
947: be represented by character strings with attached attributes. Attributes may
1.1 cvs 948: also be attached to constructed elements. Thus, an attribute indicating the
949: language can be attached to a single word or to a large part of a
1.18 cvs 950: document.</p>
1.30 cvs 951:
952: <p>In fact, an attribute can be any piece of information which is linked to a
1.1 cvs 953: part of a document and which can be used by agents which work on the document.
954: For example, the language in which the document is written determines the set
955: of characters used by an editor or formatter. It also determines the
956: algorithm or hyphenation dictionary to be used. The attribute ``keyword''
957: facilitates the work of an information retrieval system. The attribute
958: ``index word'' allows a formatter to automatically construct an index at the
1.18 cvs 959: end of the document.</p>
1.30 cvs 960:
961: <p>As with the types of constructed elements, the attributes and the values
962: they can take are defined separately in each generic logical structure, not in
963: the meta-model, according to the needs of the document class or the nature of
964: the object.</p>
965:
966: <p>Many types of attributes are offered: numeric, textual, references, and
1.18 cvs 967: enumerations:</p>
968: <ul>
1.30 cvs 969: <li><em>Numeric attributes</em> can take integer values (negative, positive,
970: or null).</li>
971: <li><em>Textual attributes</em> have as their values character strings.</li>
972: <li><em>Reference attributes</em> designate an element of the logical
973: structure.</li>
974: <li><em>Enumeration attributes</em> can take one value from a limited list
975: of possible values, each value being a name.</li>
1.18 cvs 976: </ul>
1.30 cvs 977:
978: <p>In a generic structure, there is a distinction between <em>global
1.18 cvs 979: attributes</em> and <em>local attributes</em>. A global attribute can be
1.1 cvs 980: applied to every element type defined in the generic structure where it is
981: specified. In contrast, a local attribute can only be applied to certain
982: types of elements, even only a single type. The ``language'' attribute
983: presented above is an example of a global attribute. An example of a local
984: attribute is the rank of an author (principal author of the document or
985: secondary author): this attribute can only be applied sensibly to an element
1.18 cvs 986: of the ``author'' type.</p>
1.30 cvs 987:
988: <p>Attributes can be assigned to the elements which make up the document in
989: many different ways. The author can freely and dynamically place them on any
990: part of the document in order to attach supplementary information of his/her
1.18 cvs 991: choice. However, attributes may only be assigned in accordance with the rules
992: of the generic structure; in particular, local attributes can only be assigned
993: to those element types for which they are defined.</p>
1.30 cvs 994:
995: <p>In the generic structure, certain local attributes can be made mandatory
996: for certain element types. In this case, Thot automatically associates the
1.2 cvs 997: attribute with the elements of this type and it requires the user to provide a
1.18 cvs 998: value for this attribute.</p>
1.30 cvs 999:
1000: <p>Attributes can also be automatically assigned, with a given value, by every
1.1 cvs 1001: application processing the document in order to systematically add a piece of
1002: information to certain predefined elements of the document. By way of
1003: example, in a report containing a French abstract and an English abstract,
1004: each of the two abstracts is defined as a sequence of paragraphs. The first
1005: abstract has a value of ``French'' for the ``language'' attribute while the
1.18 cvs 1006: second abstract's ``language'' attribute has a value of ``English''.</p>
1.30 cvs 1007:
1008: <p>In the case of mark pairs, attributes are logically associated with the
1009: pair as a whole, but are actually attached to the first mark.</p>
1.18 cvs 1010: </div>
1.1 cvs 1011:
1.18 cvs 1012: <div class="subsection">
1.30 cvs 1013: <h3><a name="sectc316">Discussion of the model</a></h3>
1.1 cvs 1014:
1.30 cvs 1015: <p>The notions of attribute, constructor, structured element, and associated
1.1 cvs 1016: element are used in the definition of generic logical structures of documents
1017: and objects. The problem is to assemble them to form generic structures. In
1018: fact, many types of elements and attributes can be found in a variety of
1019: generic structures. Rather than redefine them for each structure in which
1020: they appear, it is best to share them between structures. The object classes
1021: already fill this sharing function. If a mathematical class is defined, its
1022: formulas can be used in many different document classes, without redefining
1023: the structure of each class. This problem arises not only for the objects
1024: considered here; it also arises for the commonplace textual elements found in
1025: many document classes. This is the reason why the notion of object is so
1026: broad and why paragraphs and enumerations are also considered to be objects.
1027: These object classes not only permit the sharing of the structures of
1.18 cvs 1028: elements, but also of the attributes defined in the generic structures.</p>
1.30 cvs 1029:
1030: <p>Structure, such as that presented here, can appear very rigid, and it is
1.1 cvs 1031: possible to imagine that a document editing system based on this model could
1032: prove very constraining to the user. This is, in fact, a common criticism of
1033: syntax-directed editors. This defect can be avoided with Thot, primarily for
1.18 cvs 1034: three reasons:</p>
1035: <ul>
1.30 cvs 1036: <li>the generic structures are not fixed in the model itself,</li>
1037: <li>the model takes the dynamics of documents into account,</li>
1038: <li>the constructors offer great flexibility.</li>
1.18 cvs 1039: </ul>
1.30 cvs 1040:
1041: <p>When the generic structure of a document is not predefined, but rather is
1.1 cvs 1042: constructed specifically for each document class, it can be carefully adapted
1043: to the current needs. In cases where the generic structure is inadequate for
1044: a particular document of the class, it is always possible either to create a
1045: new class with a generic structure well suited to the new case or to extend
1046: the generic structure of the existing class to take into account the specifics
1047: of the document which poses the problem. These two solutions can also be
1.18 cvs 1048: applied to objects whose structures prove to be poorly designed.</p>
1.30 cvs 1049:
1050: <p>The model is sufficiently flexible to take into account all the phases of
1051: the life of the document. When a generic structure specifies that a report
1052: must contain a title, an abstract, an introduction, at least two chapters, and
1053: a conclusion, this means only that a report, <em>upon completion</em>, will
1054: have to contain all of these elements. When the author begins writing, none
1055: of these elements is present. Thot uses this model. Therefore, it tolerates
1.2 cvs 1056: documents which do not conform strictly to the generic structure of their
1057: class; it also considers the generic logical structure to be a way of helping
1.18 cvs 1058: the user in the construction of a complex document.</p>
1.30 cvs 1059:
1060: <p>In contrast, other applications may reject a document which does not
1061: conform strictly to its generic structure. This is, for example, what is done
1062: by compilers which refuse to generate code for a program which is not
1.1 cvs 1063: syntactically correct. This might also occur when using a document
1.18 cvs 1064: application for a report which does not have an abstract or title.</p>
1.30 cvs 1065:
1066: <p>The constructors of the document model bring a great flexibility to the
1.1 cvs 1067: generic structures. A choice constructor (and even more, a unit or schema
1068: constructor) can represent several, very different elements. The list
1069: constructor permits the addition of more elements of the same type. Used
1070: together, these two constructors permit any series of elements of different
1071: types. Of course, this flexibility can be reduced wherever necessary since a
1072: generic structure can limit the choices or the number of elements in a
1.18 cvs 1073: list.</p>
1.30 cvs 1074:
1075: <p>Another difficulty linked to the use of structure in the document model
1.1 cvs 1076: resides in the choice of the level of the structure. The structure of a
1077: discussion could be extracted from the text itself via linguistic analysis.
1078: Some studies are exploring this approach, but the model of Thot excludes this
1079: type of structure. It only takes into account the logical structure provided
1.18 cvs 1080: explicitly by the author.</p>
1.30 cvs 1081:
1082: <p>However, the level of structure of the model is not imposed. Each generic
1.1 cvs 1083: structure defines its own level of structure, adapted to the document class or
1084: object and to the ways in which it will be processed. If it will only be
1085: edited and printed, a relatively simple structure suffices. If more
1086: specialized processing will be applied to it, the structure must represent the
1087: element types on which this processing must act. By way of example, a simple
1088: structure is sufficient for printing formulas, but a more complex structure is
1089: required to perform symbolic or numeric calculations on the mathematical
1.18 cvs 1090: expressions. The document model of Thot allows both types of structure.</p>
1091: </div>
1092: </div>
1.1 cvs 1093:
1.18 cvs 1094: <div class="section">
1.30 cvs 1095: <h2><a name="sectb32">The definition language for generic structures</a></h2>
1.1 cvs 1096:
1.30 cvs 1097: <p>Generic structures, which form the basis of the document model of Thot, are
1.1 cvs 1098: specified using a special language. This definition language, called S, is
1.18 cvs 1099: described in this section.</p>
1.30 cvs 1100:
1101: <p>Each generic structure, which defines a class of documents or objects, is
1.2 cvs 1102: specified by a file, written in the S language, which is called a
1.18 cvs 1103: <em>structure schema</em>. Structure schemas are compiled into tables, called
1104: structure tables, which are used by Thot and which determine its behavior.</p>
1.1 cvs 1105:
1.18 cvs 1106: <div class="subsection">
1.30 cvs 1107: <h3><a name="sectc321">Writing Conventions</a></h3>
1.1 cvs 1108:
1.30 cvs 1109: <p>The grammar of S, like those of the languages P and T presented later, is
1.1 cvs 1110: described using the meta-language M, derived from the Backus-Naur Form
1.18 cvs 1111: (BNF).</p>
1.30 cvs 1112:
1113: <p>In this meta-language each rule of the grammar is composed of a grammar
1114: symbol followed by an equals sign (`=') and the right part of the rule. The
1115: equals sign plays the same role as the traditional `::=' of BNF: it indicates
1116: that the right part defines the symbol of the left part. In the right
1117: part,</p>
1.18 cvs 1118: <dl>
1.30 cvs 1119: <dt>concatenation</dt>
1120: <dd>is shown by the juxtaposition of symbols;</dd>
1121: <dt>character strings</dt>
1122: <dd>between apostrophes ' represent terminal symbols, that is, keywords in
1123: the language defined. Keywords are written here in upper-case letters,
1.31 cvs 1124: but can be written in any combination of upper and lower-case letters.
1.30 cvs 1125: For example, the keyword <tt>DEFPRES</tt> of S can also be written as
1126: <tt>defpres</tt> or <tt>DefPres</tt>.</dd>
1127: <dt>material between brackets</dt>
1128: <dd>(`[' and `]') is optional;</dd>
1129: <dt>material between angle brackets</dt>
1130: <dd>(`<' and `>') can be repeated many times or omitted;</dd>
1131: <dt>the slash</dt>
1132: <dd>(`/') indicates an alternative, a choice between the options separated
1133: by the slash character;</dd>
1134: <dt>the period</dt>
1135: <dd>marks the end of a rule;</dd>
1136: <dt>text between braces</dt>
1137: <dd>(`{' and `}') is simply a comment.</dd>
1.18 cvs 1138: </dl>
1.30 cvs 1139:
1140: <p>The M meta-language also uses the concepts of identifiers, strings, and
1.18 cvs 1141: integers:</p>
1142: <dl>
1.30 cvs 1143: <dt><tt>NAME</tt></dt>
1144: <dd>represents an identifier, a sequence of letters (upper or lower-case),
1145: digits, and underline characters (`_'), beginning with a letter. Also
1146: considered a letter is the sequence of characters `<tt>\nnn</tt>' where
1147: the letter <tt>n</tt> represents the ISO Latin-1 code of the letter in
1148: octal. It is thus possible to use accented letters in identifiers. The
1149: maximum length of identifiers is fixed by the compiler. It is normally
1150: 31 characters.
1151: <p>Unlike keywords, upper and lower-case letters are distinct in
1152: identifiers. Thus, <tt>Title</tt>, <tt>TITLE</tt>, and <tt>title</tt>
1153: are considered different identifiers.</p>
1154: </dd>
1155: <dt><tt>STRING</tt></dt>
1156: <dd>represents a string. This is a string of characters delimited by
1.31 cvs 1157: apostrophes. If an apostrophe must appear in a string, it is doubled. As
1158: with identifiers, strings can contain characters represented by their
1.30 cvs 1159: octal code (after a backslash). As with apostrophes, if a backslash
1160: must appear in a string, it is doubled.</dd>
1161: <dt><tt>NUMBER</tt></dt>
1162: <dd>represents a positive integer or zero (without a sign), or said
1163: another way, a sequence of decimal digits.</dd>
1.18 cvs 1164: </dl>
1.30 cvs 1165:
1166: <p>The M language can be used to define itself as follows:</p>
1.18 cvs 1167: <pre>{ Any text between braces is a comment. }
1.30 cvs 1168: Grammar = Rule < Rule > 'END' .
1169: { The < and > signs indicate zero }
1.1 cvs 1170: { or more repetitions. }
1171: { END marks the end of the grammar. }
1172: Rule = Ident '=' RightPart '.' .
1173: { The period indicates the end of a rule }
1174: RightPart = RtTerminal / RtIntermed .
1175: { The slash indicates a choice }
1176: RtTerminal ='NAME' / 'STRING' / 'NUMBER' .
1177: { Right part of a terminal rule }
1.30 cvs 1178: RtIntermed = Possibility < '/' Possibility > .
1.1 cvs 1179: { Right part of an intermediate rule }
1.30 cvs 1180: Possibility = ElemOpt < ElemOpt > .
1181: ElemOpt = Element / '[' Element < Element > ']' /
1182: '<' Element < Element > '>' .
1.1 cvs 1183: { Brackets delimit optional parts }
1184: Element = Ident / KeyWord .
1185: Ident = NAME .
1186: { Identifier, sequence of characters }
1187: KeyWord = STRING .
1188: { Character string delimited by apostrophes }
1.18 cvs 1189: END</pre>
1190: </div>
1.1 cvs 1191:
1.18 cvs 1192: <div class="subsection">
1.30 cvs 1193: <h3><a name="sectc322">Extension schemas</a></h3>
1.1 cvs 1194:
1.30 cvs 1195: <p>A structure schema defines the generic logical structure of a class of
1.1 cvs 1196: documents or objects, independent of the operations which can be performed on
1197: the documents. However, certain applications may require particular
1198: information to be represented by the structure for the documents that they
1199: operate on. Thus a document version manager will need to indicate in the
1200: document the parts which belong to one version or another. An indexing system
1201: will add highly-structured index tables as well as the links between these
1.18 cvs 1202: tables and the rest of the document.</p>
1.30 cvs 1203:
1204: <p>Thus, many applications need to extend the generic structure of the
1205: documents on which they operate to introduce new attributes, associated
1206: elements or element types. These additions are specific to each application
1207: and must be able to be applied to any generic structure: users will want to
1208: manage versions or construct indices for many types of documents. Extension
1209: schemas fulfill this role: they define attributes, elements, associated
1210: elements, units, etc., but they can only be used jointly with a structure
1211: schema that they complete. Otherwise, structure schemas can always be used
1212: without these extensions when the corresponding applications are not
1213: available.</p>
1.18 cvs 1214: </div>
1.1 cvs 1215:
1.18 cvs 1216: <div class="subsection">
1.30 cvs 1217: <h3><a name="sectc323">The general organization of structure schemas</a></h3>
1.1 cvs 1218:
1.30 cvs 1219: <p>Every structure schema begins with the keyword <tt>STRUCTURE</tt> and ends
1.18 cvs 1220: with the keyword <tt>END</tt>. The keyword <tt>STRUCTURE</tt> is followed by
1221: the keyword <tt>EXTENSION</tt> in the case where the schema defines an
1.1 cvs 1222: extension, then by the name of the generic structure which the schema defines
1223: (the name of the document or object class). The name of the structure is
1.18 cvs 1224: followed by a semicolon.</p>
1.30 cvs 1225:
1226: <p>In the case of a complete schema (that is, a schema which is not an
1.1 cvs 1227: extension), the definition of the name of the structure is followed by the
1228: declarations of the default presentation schema, the global attributes, the
1.34 ! cvs 1229: structure rules, the associated elements, the units, the skeleton elements and
! 1230: the exceptions. Only the definition of the structure rules is required. Each
! 1231: series of declarations begins with a keyword: <tt>DEFPRES</tt>, <tt>ATTR</tt>,
! 1232: <tt>STRUCT</tt>, <tt>ASSOC</tt>, <tt>UNITS</tt>, <tt>EXPORT</tt>,
! 1233: <tt>EXCEPT</tt>.</p>
! 1234:
! 1235: <p>In the case of an extension schema, there are no skeleton elements and the
! 1236: <tt>STRUCT</tt> section is optional, while that section is required in a
! 1237: schema that is not an extension. On the other hand, extension schemas can
! 1238: contain an <tt>EXTENS</tt> section, which must not appear in a schema which is
! 1239: not an extension; this section defines the complements to attach to the rules
! 1240: found in the schema to which the extension will be added. The sections
! 1241: <tt>ATTR</tt>, <tt>STRUCT</tt>, <tt>ASSOC</tt>, and <tt>UNITS</tt> define new
! 1242: attributes, new elements, new associated elements, and new units which add
! 1243: their definitions to the principal schema.</p>
1.18 cvs 1244: <pre> StructSchema ='STRUCTURE' ElemID ';'
1.1 cvs 1245: 'DEFPRES' PresID ';'
1246: [ 'ATTR' AttrSeq ]
1247: 'STRUCT' RulesSeq
1248: [ 'ASSOC' RulesSeq ]
1249: [ 'UNITS' RulesSeq ]
1250: [ 'EXPORT' SkeletonSeq ]
1251: [ 'EXCEPT' ExceptSeq ]
1252: 'END' .
1.18 cvs 1253: ElemID = NAME .</pre>
1.30 cvs 1254:
1255: <p>or</p>
1.18 cvs 1256: <pre> ExtensSchema ='STRUCTURE' 'EXTENSION' ElemID ';'
1.1 cvs 1257: 'DEFPRES' PresID ';'
1258: [ 'ATTR' AttrSeq ]
1259: [ 'STRUCT' RulesSeq ]
1260: [ 'EXTENS' ExtensRuleSeq ]
1261: [ 'ASSOC' RulesSeq ]
1262: [ 'UNITS' RulesSeq ]
1263: [ 'EXCEPT' ExceptSeq ]
1264: 'END' .
1.18 cvs 1265: ElemID = NAME .</pre>
1266: </div>
1.1 cvs 1267:
1.18 cvs 1268: <div class="subsection">
1.30 cvs 1269: <h3><a name="sectc324">The default presentation</a></h3>
1.1 cvs 1270:
1.30 cvs 1271: <p>It was shown <a href="#mulpres">above</a> that many different presentations
1.1 cvs 1272: are possible for documents and objects of the same class. The structure
1.18 cvs 1273: schema defines a preferred presentation for the class, called the <em>default
1274: presentation</em>. Like generic structures, presentations are described by
1275: programs, called <em>presentation schemas</em>, which are written in a
1276: specific language, P, presented <a href="#sectb42">later</a> in this document.
1277: The name appearing after the keyword <tt>DEFPRES</tt> is the name of the
1.2 cvs 1278: default presentation schema. When a new document is created, Thot will use
1279: this presentation schema by default, but the user remains free to choose
1.18 cvs 1280: another if s/he wishes.</p>
1281: <pre> PresID = NAME .</pre>
1282: </div>
1.1 cvs 1283:
1.18 cvs 1284: <div class="subsection">
1.30 cvs 1285: <h3><a name="sectc325">Global Attributes</a></h3>
1.1 cvs 1286:
1.30 cvs 1287: <p>If the generic structure includes global attributes of its own, they are
1.18 cvs 1288: declared after the keyword <tt>ATTR</tt>. Each global attribute is defined by
1.1 cvs 1289: its name, followed by an equals sign and the definition of its type. The
1.18 cvs 1290: declaration of a global attribute is terminated by a semi-colon.</p>
1.30 cvs 1291:
1292: <p>For attributes of the numeric, textual, or reference types, the type is
1.18 cvs 1293: indicated by a keyword, <tt>INTEGER</tt>, <tt>TEXT</tt>, or <tt>REFERENCE</tt>
1294: respectively.</p>
1.30 cvs 1295:
1296: <p>In the case of a reference attribute, the keyword <tt>REFERENCE</tt> is
1.1 cvs 1297: followed by the type of the referenced element in parentheses. It can refer
1.18 cvs 1298: to any type at all, specified by using the keyword <tt>ANY</tt>, or to a
1.1 cvs 1299: specific type. In the latter case, the element type designated by the
1.18 cvs 1300: reference can be defined either in the <a href="#sectc327"><tt>STRUCT</tt>
1301: section</a> of the same structure schema or in the <tt>STRUCT</tt> section of
1.1 cvs 1302: another structure schema. When the type is defined in another schema, the
1303: element type is followed by the name of the structure schema (within
1304: parentheses) in which it is defined. The name of the designated element type
1.18 cvs 1305: can be preceded by the keyword <tt>First</tt> or <tt>Second</tt>, but only in
1306: the case where the type is defined as <a href="#sectd3285">a pair</a>. These
1.1 cvs 1307: keywords indicate whether the attribute must designate the first mark of the
1308: pair or the second. If the reference refers to a pair and neither of these
1.18 cvs 1309: two keywords is present, then the first mark is used.</p>
1.30 cvs 1310:
1311: <p>In the case of an enumeration attribute, the equals sign is followed by the
1.1 cvs 1312: list of names representing the possible values of the attribute, the names
1313: being separated from each other by commas. An enumeration attribute has at
1314: least one possible value; the maximum number of values is defined by the
1.18 cvs 1315: compiler for the S language.</p>
1.30 cvs 1316: <pre> AttrSeq = Attribute < Attribute > .
1.1 cvs 1317: Attribute = AttrID '=' AttrType ';' .
1318: AttrType = 'INTEGER' / 'TEXT' /
1319: 'REFERENCE' '(' RefType ')' /
1320: ValueSeq .
1321: RefType = 'ANY' / [ FirstSec ] ElemID [ ExtStruct ] .
1322: FirstSec = 'First' / 'Second' .
1323: ExtStruct = '(' ElemID ')' .
1.30 cvs 1324: ValueSeq = AttrVal < ',' AttrVal > .
1.1 cvs 1325: AttrID = NAME .
1.18 cvs 1326: AttrVal = NAME .</pre>
1.30 cvs 1327:
1328: <p>There is a predefined global text attribute, the <em>language</em>, which
1329: is automatically added to every Thot structure schema. This attribute allows
1.2 cvs 1330: Thot to perform certain actions, such as hyphenation and spell-checking, which
1331: cannot be performed without knowing the language in which each part of the
1332: document is written. This attribute can be used just like any explicitly
1.18 cvs 1333: declared attribute: the system acts as if every structure schema contains</p>
1334: <pre>ATTR
1335: Language = TEXT;</pre>
1.30 cvs 1336:
1.18 cvs 1337: <blockquote class="example">
1.30 cvs 1338: <p><strong>Example:</strong></p>
1339:
1340: <p>The following specification defines the global enumeration attribute
1341: WordType.</p>
1342: <pre>ATTR
1.18 cvs 1343: WordType = Definition, IndexWord, DocumentTitle;</pre>
1344: </blockquote>
1345: </div>
1.1 cvs 1346:
1.18 cvs 1347: <div class="subsection">
1.30 cvs 1348: <h3><a name="sectc327">Structured elements</a></h3>
1.1 cvs 1349:
1.30 cvs 1350: <p>The rules for defining structured elements are required, except in an
1.1 cvs 1351: extension schema: they constitute the core of a structure schema, since they
1352: define the structure of the different types of elements that occur in a
1.18 cvs 1353: document or object of the class defined by the schema.</p>
1.30 cvs 1354:
1355: <p>The first structure rule after the keyword <tt>STRUCT</tt> must define the
1.1 cvs 1356: structure of the class whose name appears in the first instruction
1.18 cvs 1357: (<tt>STRUCTURE</tt>) of the schema. This is the root rule of the schema,
1358: defining the root of the document tree or object tree.</p>
1.30 cvs 1359:
1360: <p>The remaining rules may be placed in any order, since the language permits
1361: the definition of element types before or after their use, or even in the same
1.1 cvs 1362: instruction in which they are used. This last case allows the definition of
1.18 cvs 1363: recursive structures.</p>
1.30 cvs 1364:
1365: <p>Each rule is composed of a name (the name of the element type whose
1366: structure is being defined) followed by an equals sign and a structure
1367: definition.</p>
1368:
1369: <p>If any local attributes are associated with the element type defined by the
1.2 cvs 1370: rule, they appear between parentheses after the type name and before the
1.18 cvs 1371: equals sign. The parentheses contain, first, the keyword <tt>ATTR</tt>, then
1.2 cvs 1372: the list of local attributes, separated by commas. Each local attribute is
1373: composed of the name of the attribute followed by an equals sign and the
1.18 cvs 1374: definition of the attribute's type, just as in the definition of <a
1375: href="#sectc325">global attributes</a>. The name of the attribute can be
1.2 cvs 1376: preceded by an exclamation point to indicate that the attribute must always be
1377: present for this element type. The same attribute, identified by its name,
1378: can be defined as a local attribute for multiple element types. In this
1379: case, the equals sign and definition of the attribute type need only appear in
1380: the first occurrence of the attribute. It should be noted that global
1.18 cvs 1381: attributes cannot also be defined as local attributes.</p>
1.30 cvs 1382:
1383: <p>If any <a href="#sectd3135">extensions</a> are defined for this element
1384: type, a plus sign follows the structure definition and the names of the
1385: extension element types appear between parentheses after the plus. If there
1386: are multiple extensions, they are separated by commas. These types can either
1387: be defined in the same schema, defined in other schemas, or they may be base
1.18 cvs 1388: types identified by the keywords <tt>TEXT</tt>, <tt>GRAPHICS</tt>,
1389: <tt>SYMBOL</tt>, or <tt>PICTURE</tt>.</p>
1.30 cvs 1390:
1391: <p><a href="#sectd3135">Restrictions</a> are indicated in the same manner as
1.18 cvs 1392: extensions, but they are introduced by a minus sign and they come after the
1393: extensions, or if there are no extensions, after the structure definition.</p>
1.30 cvs 1394:
1395: <p>If the values of attributes must be attached systematically to this element
1.18 cvs 1396: type, they are introduced by the keyword <tt>WITH</tt> and declared in the
1.1 cvs 1397: form of a list of fixed-value attributes. When such definitions of fixed
1.18 cvs 1398: attribute values appear, they are always the last part of the rule.</p>
1.30 cvs 1399:
1400: <p>The rule is terminated by a semicolon.</p>
1401: <pre> RuleSeq = Rule < Rule > .
1.1 cvs 1402: Rule = ElemID [ LocAttrSeq ] '=' DefWithAttr ';'.
1.30 cvs 1403: LocAttrSeq = '(' 'ATTR' LocAttr < ';' LocAttr > ')' .
1.1 cvs 1404: LocAttr = [ '!' ] AttrID [ '=' AttrType ] .
1405: DefWithAttr = Definition
1406: [ '+' '(' ExtensionSeq ')' ]
1407: [ '-' '(' RestrictSeq ')' ]
1408: [ 'WITH' FixedAttrSeq ] .
1.30 cvs 1409: ExtensionSeq = ExtensionElem < ',' ExtensionElem > .
1.1 cvs 1410: ExtensionElem = ElemID / 'TEXT' / 'GRAPHICS' /
1411: 'SYMBOL' / 'PICTURE' .
1.30 cvs 1412: RestrictSeq = RestrictElem < ',' RestrictElem > .
1.1 cvs 1413: RestrictElem = ElemID / 'TEXT' / 'GRAPHICS' /
1.18 cvs 1414: 'SYMBOL' / 'PICTURE' .</pre>
1.30 cvs 1415:
1416: <p>The list of fixed-value attributes is composed of a sequence of
1.1 cvs 1417: attribute-value pairs separated by commas. Each pair contains the name of the
1418: attribute and the fixed value for this element type, the two being separated
1419: by an equals sign. If the sign is preceded by a question mark the given value
1420: is only an initial value that may be modified later rather than a value fixed
1421: for all time. Reference attributes are an exception to this norm. They
1422: cannot be assigned a fixed value, but when the name of such an attribute
1423: appears this indicates that this element type must have a valid value for the
1.2 cvs 1424: attribute. For the other attribute types, the fixed value is indicated by a
1.1 cvs 1425: signed integer (numeric attributes), a character string between apostrophes
1.18 cvs 1426: (textual attributes) or the name of a value (enumeration attributes).</p>
1.30 cvs 1427:
1428: <p>Fixed-value attributes can either be <a href="#sectc325">global</a> or
1429: local to the element type for which they are fixed, but they must be declared
1430: before they are used.</p>
1431: <pre> FixedAttrSeq = FixedAttr < ',' FixedAttr > .
1.1 cvs 1432: FixedAttr = AttrID [ FixedOrModifVal ] .
1433: FixedOrModifVal = [ '?' ] '=' FixedValue .
1434: FixedValue = [ '-' ] NumValue / TextVal / AttrVal .
1435: NumValue = NUMBER .
1.18 cvs 1436: TextVal = STRING .</pre>
1437: </div>
1.1 cvs 1438:
1.18 cvs 1439: <div class="subsection">
1.30 cvs 1440: <h3><a name="sectc328">Structure definitions</a></h3>
1.1 cvs 1441:
1.30 cvs 1442: <p>The structure of an element type can be a simple base type or a constructed
1.18 cvs 1443: type.</p>
1.30 cvs 1444:
1445: <p>For constructed types, it is frequently the case that similar structures
1.1 cvs 1446: appear in many places in a document. For example the contents of the
1447: abstract, of the introduction, and of a section can have the same structure,
1448: that of a sequence of paragraphs. In this case, a single, common structure
1449: can be defined (the paragraph sequence in this example), and the schema is
1450: written to indicate that each element type possesses this structure, as
1.18 cvs 1451: follows:</p>
1452: <pre> Abstract = Paragraph_sequence;
1.1 cvs 1453: Introduction = Paragraph_sequence;
1.18 cvs 1454: Section_contents = Paragraph_sequence;</pre>
1.30 cvs 1455:
1456: <p>The equals sign means ``has the same structure as''.</p>
1457:
1458: <p>If the element type defined is a simple base type, this is indicated by one
1459: of the keywords <tt>TEXT</tt>, <tt>GRAPHICS</tt>, <tt>SYMBOL</tt>, or
1.18 cvs 1460: <tt>PICTURE</tt>. If some local attributes must be associated with a base
1.1 cvs 1461: type, the keyword of the base type is followed by the declaration of the local
1.18 cvs 1462: attributes using the syntax <a href="#sectc327">presented above.</a></p>
1.30 cvs 1463:
1464: <p>In the case of an open choice, the type is indicated by the keyword
1.18 cvs 1465: <tt>UNIT</tt> for units or the keyword <tt>NATURE</tt> for objects having a
1466: structure defined by any other schema.</p>
1.30 cvs 1467:
1468: <p>A unit represents one of the two following categories:</p>
1.18 cvs 1469: <ul>
1.30 cvs 1470: <li>a base type: text, graphical element, symbol, picture,</li>
1471: <li>an element whose type is chosen from among the types defined as units in
1472: the <tt>UNITS</tt> section of the document's structure schema. It can
1473: also be chosen from among the types defined as <a
1474: href="#sectd3132">units</a> in the <a href="#sectc3212"><tt>UNITS</tt>
1475: section</a> of the structure schemas that defines the ancestors of the
1476: element to which the rule is applied.</li>
1.18 cvs 1477: </ul>
1.30 cvs 1478:
1479: <p>Before the creation of an element defined as a unit, Thot asks the user to
1.18 cvs 1480: choose between the categories of elements.</p>
1.30 cvs 1481:
1482: <p>Thus, the contents of a paragraph can be specified as a sequence of units,
1.1 cvs 1483: which will permit the inclusion in the paragraphs of character strings,
1484: symbols, and various elements, such as cross-references, if these are defined
1.18 cvs 1485: as units.</p>
1.30 cvs 1486:
1487: <p>A schema object (keyword <tt>NATURE</tt>) represents an object defined by a
1.1 cvs 1488: structure schema freely chosen from among the available schemas; in the case
1489: the element type is defined by the first rule (the root rule) of the chosen
1.18 cvs 1490: schema.</p>
1.30 cvs 1491:
1492: <p>If the element type defined is a constructed type, the list, aggregate,
1.1 cvs 1493: choice, and reference constructors are used. In this case the definition
1494: begins with a keyword identifying the constructor. This keyword is followed
1.18 cvs 1495: by a syntax specific to each constructor.</p>
1.30 cvs 1496:
1497: <p>The local attribute definitions appear after the name of the element type
1.18 cvs 1498: being defined, if this element type has <a href="#sectc327">local
1499: attributes</a>.</p>
1500: <pre> Definition = BaseType [ LocAttrSeq ] / Constr / Element .
1.1 cvs 1501: BaseType = 'TEXT' / 'GRAPHICS' / 'SYMBOL' / 'PICTURE' /
1502: 'UNIT' / 'NATURE' .
1503: Element = ElemID [ ExtOrDef ] .
1504: ExtOrDef = 'EXTERN' / 'INCLUDED' /
1505: [ LocAttrSeq ] '=' Definition .
1506: Constr = 'LIST' [ '[' min '..' max ']' ] 'OF'
1507: '(' DefWithAttr ')' /
1508: 'BEGIN' DefOptSeq 'END' /
1509: 'AGGREGATE' DefOptSeq 'END' /
1510: 'CASE' 'OF' DefSeq 'END' /
1511: 'REFERENCE' '(' RefType ')' /
1.18 cvs 1512: 'PAIR' .</pre>
1.1 cvs 1513:
1.18 cvs 1514: <div class="subsubsection">
1.30 cvs 1515: <h4><a name="sectd3281">List</a></h4>
1.1 cvs 1516:
1.30 cvs 1517: <p>The list constructor permits the definition of an element type composed of
1518: a list of elements, all of the same type. A list definition begins with the
1.18 cvs 1519: <tt>LIST</tt> keyword followed by an optional range, the keyword <tt>OF</tt>,
1.1 cvs 1520: and the definition, between parentheses, of the element type which must
1521: compose the list. The optional range is composed of the minimum and maximum
1522: number of elements for the list separated by two periods and enclosed by
1523: brackets. If the range is not present, the number of list elements is
1524: unconstrained. When only one of the two bounds of the range is unconstrained,
1525: it is represented by a star ('*') character. Even when both bounds are
1.18 cvs 1526: unconstrained, they can be specified by <tt>[*..*]</tt>, but it is simpler not
1527: to specify any bound.</p>
1528: <pre> 'LIST' [ '[' min '..' max ']' ]
1.1 cvs 1529: 'OF' '(' DefWithAttr ')'
1530: min = Integer / '*' .
1531: max = Integer / '*' .
1.18 cvs 1532: Integer = NUMBER .</pre>
1.30 cvs 1533:
1534: <p>Before the document is edited, Thot creates the minimum number of elements
1535: for the list. If no minimum was given, it creates a single element. If a
1536: maximum number of elements is given and that number is attained, the editor
1537: refuses to create new elements for the list.</p>
1538:
1539: <blockquote class="example">
1540: <p><strong>Example:</strong></p>
1541:
1542: <p>The following two instructions define the body of a document as a
1543: sequence of at least two chapters and the contents of a section as a
1544: sequence of paragraphs. A single paragraph can be the entire contents of a
1545: section.</p>
1546: <pre>Body = LIST [2..*] OF (Chapter);
1.18 cvs 1547: Section_contents = LIST OF (Paragraph);</pre>
1548: </blockquote>
1549: </div>
1.1 cvs 1550:
1.18 cvs 1551: <div class="subsubsection">
1.30 cvs 1552: <h4><a name="sectd3282">Aggregate</a></h4>
1.1 cvs 1553:
1.30 cvs 1554: <p>The aggregate constructor is used to define an element type as a collection
1555: of sub-elements, each having a fixed type. The collection may be ordered or
1.1 cvs 1556: unordered. The elements composing the collection are called
1.18 cvs 1557: <em>components</em>. In the definition of an aggregate, a keyword indicates
1558: whether or not the aggregate is ordered: <tt>BEGIN</tt> for an ordered
1559: aggregate, <tt>AGGREGATE</tt> for an unordered aggregate. This keyword is
1.1 cvs 1560: followed by the list of component type definitions which is terminated by the
1.18 cvs 1561: <tt>END</tt> keyword. The component type definitions are separated by
1562: commas.</p>
1.30 cvs 1563:
1564: <p>Before creating an aggregate, the Thot editor creates all the aggregate's
1.1 cvs 1565: components in the order they appear in the structure schema, even for
1566: unordered aggregates. However, unlike ordered aggregates, the components of
1567: an unordered aggregate may be rearranged using operations of the Thot editor.
1568: The exceptions to the rule are any components whose name was preceded by a
1569: question mark character ('?'). These components, which are optional, can be
1570: created by explicit request, possibly at the time the aggregate is created,
1.18 cvs 1571: but they are not created automatically <em>prior</em> to the creation of the
1572: aggregate.</p>
1573: <pre> 'BEGIN' DefOptSeq 'END'
1.30 cvs 1574: DefOptSeq = DefOpt ';' < DefOpt ';' > .
1.18 cvs 1575: DefOpt = [ '?' ] DefWithAttr .</pre>
1.30 cvs 1576:
1.18 cvs 1577: <blockquote class="example">
1.30 cvs 1578: <p><strong>Example:</strong></p>
1579:
1580: <p>In a bilingual document, each paragraph has an English version and a
1581: French version. In certain cases, the translator wants to add a marginal
1582: note, but this note is present in very few paragraphs. Thus, it must not be
1583: created systematically for every paragraph. A bilingual paragraph of this
1584: type is declared:</p>
1585: <pre>Bilingual_paragraph = BEGIN
1.1 cvs 1586: French_paragraph = TEXT;
1587: English_paragraph = TEXT;
1588: ? Note = TEXT;
1.18 cvs 1589: END;</pre>
1590: </blockquote>
1591: </div>
1.1 cvs 1592:
1.18 cvs 1593: <div class="subsubsection">
1.30 cvs 1594: <h4><a name="sectd3283">Choice</a></h4>
1.1 cvs 1595:
1.30 cvs 1596: <p>The choice constructor permits the definition of an element type which is
1.18 cvs 1597: chosen from among a set of possible types. The keywords <tt>CASE</tt> and
1598: <tt>OF</tt> are followed by a list of definitions of possible types, which are
1599: separated by semicolons and terminated by the <tt>END</tt> keyword.</p>
1600: <pre> 'CASE' 'OF' DefSeq 'END'
1.30 cvs 1601: DefSeq = DefWithAttr ';' < DefWithAttr ';' > .</pre>
1602:
1603: <p>Before the creation of an element defined as a choice, the Thot editor
1.1 cvs 1604: presents the list of possible types for the element to the user. The user has
1.18 cvs 1605: only to select the element type that s/he wants to create from this list.</p>
1.30 cvs 1606:
1607: <p>The order of the type declarations is important. It determines the order
1608: of the list presented to the user before the creation of the element. Also,
1609: when a Choice element is being created automatically, the first type in the
1610: list is used. In fact, using the Thot editor, when an empty Choice element is
1.1 cvs 1611: selected, it is possible to select this element and to enter its text from
1612: keyboard. In this case, the editor uses the first element type which can
1.18 cvs 1613: contain an atom of the character string type.</p>
1.30 cvs 1614:
1615: <p>The two special cases of the choice constructor, the <a
1.18 cvs 1616: href="#sectc328"><em>schema</em></a> and the <a
1617: href="#sectc3212"><em>unit</em></a> are discussed elsewhere.</p>
1.30 cvs 1618:
1.18 cvs 1619: <blockquote class="example">
1.30 cvs 1620: <p><strong>Example:</strong></p>
1621:
1622: <p>It is common in documents to treat a variety of objects as if they were
1623: ordinary paragraphs. Thus, a ``Paragraph'' might actually be composed of a
1624: block of text (an ordinary paragraph), or a mathematical formula whose
1625: structure is defined by another structure schema named Math, or a table,
1626: also defined by another structure schema. Here is a definition of such a
1627: paragraph:</p>
1628: <pre>Paragraph = CASE OF
1.1 cvs 1629: Simple_text = TEXT;
1630: Formula = Math;
1631: Table_para = Table;
1.18 cvs 1632: END;</pre>
1633: </blockquote>
1634: </div>
1.1 cvs 1635:
1.18 cvs 1636: <div class="subsubsection">
1.30 cvs 1637: <h4><a name="sectd3284">Reference</a></h4>
1.1 cvs 1638:
1.30 cvs 1639: <p>Like all elements in Thot, references are typed. An element type defined
1640: as a reference is a cross-reference to an element of some other given type.
1641: The keyword <tt>REFERENCE</tt> is followed by the name of a type enclosed in
1.1 cvs 1642: parentheses. When the type which is being cross-referenced is defined in
1643: another structure schema, the type name is itself followed by the name of the
1.18 cvs 1644: external structure schema in which it is defined.</p>
1.30 cvs 1645:
1646: <p>When the designated element type is a <a href="#sectd3285">mark pair</a>,
1647: it can be preceded by a <tt>FIRST</tt> or <tt>SECOND</tt> keyword. These
1.18 cvs 1648: keywords indicate whether the reference points to the first or second mark of
1649: the pair. If the reference points to a pair and neither of these two keywords
1650: is present, the reference is considered to point to the first mark of the
1651: pair.</p>
1.30 cvs 1652:
1653: <p>There is an exception to the principle of typed references: it is possible
1654: to define a reference which designates an element of any type, which can
1655: either be in the same document or another document. In this case, it suffices
1656: to put the keyword <tt>ANY</tt> in the parentheses which indicate the
1657: referenced element type.</p>
1.18 cvs 1658: <pre> 'REFERENCE' '(' RefType ')'
1659: RefType = 'ANY' / [ FirstSec ] ElemID [ ExtStruct ] .</pre>
1.30 cvs 1660:
1661: <p>When defining an inclusion, the <tt>REFERENCE</tt> keyword is not used.
1.1 cvs 1662: Inclusions with complete expansion are not declared as such in the structure
1663: schemas, since any element defined in a structure schema can be replaced by an
1664: element of the same type. Instead, inclusions without expansion or with
1665: partial expansion must be declared explicitly whenever they will include a
1666: complete object ( and not a part of an object). In this case, the object type
1667: to be included (that is, the name of its structure schema) is followed by a
1.18 cvs 1668: keyword: <tt>EXTERN</tt> for inclusion without expansion and <tt>INCLUDED</tt>
1669: for partial expansion.</p>
1.30 cvs 1670:
1671: <p>Before creating a cross-reference or an inclusion, the Thot editor asks the
1.1 cvs 1672: user to choose, from the document images displayed, the referenced or included
1.18 cvs 1673: element.</p>
1.30 cvs 1674:
1.18 cvs 1675: <blockquote class="example">
1.30 cvs 1676: <p><strong>Example:</strong></p>
1677:
1678: <p>If the types Note and Section are defined in the Article structure
1679: schema, it is possible to define, in the same structure schema, a reference
1680: to a note and a reference to a section in this manner:</p>
1681: <pre>Ref_note = REFERENCE (Note);
1.18 cvs 1682: Ref_section = REFERENCE (Section);</pre>
1.30 cvs 1683:
1684: <p>It is also possible to define the generic structure of a collection of
1685: articles, which include (with partial expansion) objects of the Article
1686: class and which possess an introduction which may include cross-references
1687: to sections of the included articles. In the Collection structure schema,
1688: the definitions are:</p>
1689: <pre>Collection = BEGIN
1.6 cvs 1690: Collection_title = TEXT;
1691: Introduction = LIST OF (Elem = CASE OF
1.1 cvs 1692: TEXT;
1693: Ref_sect;
1694: END);
1.6 cvs 1695: Body = LIST OF (Article INCLUDED);
1696: END;
1.18 cvs 1697: Ref_sect = REFERENCE (Section (Article));</pre>
1.30 cvs 1698:
1699: <p>Here we define a Folder document class which has a title and includes
1700: documents of different types, particularly Folders:</p>
1701: <pre>Folder = BEGIN
1.6 cvs 1702: Folder_title = TEXT;
1703: Folder_contents = LIST OF (Document);
1704: END;
1.1 cvs 1705:
1706: Document = CASE OF
1707: Article EXTERN;
1708: Collection EXTERN;
1709: Folder EXTERN;
1.18 cvs 1710: END;</pre>
1.30 cvs 1711:
1712: <p>Under this definition, Folder represents either an aggregate which
1713: contains a folder title and the list of included documents or an included
1714: folder. To resolve this ambiguity, in the P language, the placement of a
1715: star character in front of the type name (here, Folder) indicates an
1716: included document.</p>
1.18 cvs 1717: </blockquote>
1718: </div>
1.1 cvs 1719:
1.18 cvs 1720: <div class="subsubsection">
1.30 cvs 1721: <h4><a name="sectd3285">Mark pairs</a></h4>
1.1 cvs 1722:
1.30 cvs 1723: <p>Like other elements, mark pairs are typed. The two marks of the pair have
1724: the same type, but there exist two predefined subtypes which apply to all mark
1.18 cvs 1725: pairs: the first mark of the pair (called <tt>First</tt> in the P and T
1726: languages) and the second mark (called <tt>Second</tt>).</p>
1.30 cvs 1727:
1728: <p>In the S language, a mark pair is noted simply by the <tt>PAIR</tt>
1.18 cvs 1729: keyword.</p>
1.30 cvs 1730:
1731: <p>In the Thot editor, marks are always moved or destroyed together. The two
1.1 cvs 1732: marks of a pair have the same identifier, unique within the document, which
1.18 cvs 1733: permits intertwining mark pairs without risk of ambiguity.</p>
1734: </div>
1735: </div>
1.1 cvs 1736:
1.18 cvs 1737: <div class="subsection">
1.30 cvs 1738: <h3><a name="sectc329">Imports</a></h3>
1.1 cvs 1739:
1.30 cvs 1740: <p>Because of schema constructors, it is possible, before editing a document,
1741: to use classes defined by other structure schemas whenever they are needed. It
1742: is also possible to assign specific document classes to certain element types.
1743: In this case, these classes are simply designated by their name. In fact, if
1744: a type name is not defined in the structure schema, it is assumed that it
1.18 cvs 1745: specifies a structure defined by another structure schema.</p>
1.30 cvs 1746:
1.18 cvs 1747: <blockquote class="example">
1.30 cvs 1748: <p><strong>Example:</strong></p>
1749:
1750: <p>If the types Math and Table don't appear in the left part of a structure
1751: rule in the schema, the following two rules indicate that a formula has the
1752: structure of an object defined by the structure schema Math and that a table
1753: element has the structure of an object defined by the Table schema.</p>
1754: <pre>Formula = Math;
1.18 cvs 1755: Table_elem = Table;</pre>
1756: </blockquote>
1757: </div>
1758:
1759: <div class="subsection">
1.30 cvs 1760: <h3><a name="sectc3210">Extension rules</a></h3>
1.18 cvs 1761:
1.30 cvs 1762: <p>The <tt>EXTENS</tt> section, which can only appear in an extension schema,
1.1 cvs 1763: defines complements to the rules in the primary schema (i.e. the structure
1764: schema to which the extension schema will be applied). More precisely, this
1765: section permits the addition to an existing type of local attributes,
1.18 cvs 1766: extensions, restrictions and fixed-value attributes.</p>
1.30 cvs 1767:
1768: <p>These additions can be applied to the root rule of the primary schema,
1.18 cvs 1769: designated by the keyword <tt>Root</tt>, or to any other explicitly named
1770: rule.</p>
1.30 cvs 1771:
1772: <p>Extension rules are separated from each other by a semicolon and each
1.18 cvs 1773: extension rule has the same syntax as a <a href="#sectc327">structure
1774: rule</a>, but the part which defines the constructor is absent.</p>
1.30 cvs 1775: <pre> ExtenRuleSeq = ExtensRule ';' < ExtensRule ';' > .
1.6 cvs 1776: ExtensRule = RootOrElem [ LocAttrSeq ]
1777: [ '+' '(' ExtensionSeq ')' ]
1778: [ '-' '(' RestrictSeq ')' ]
1779: [ 'WITH' FixedAttrSeq ] .
1.18 cvs 1780: RootOrElem = 'Root' / ElemID .</pre>
1781: </div>
1.1 cvs 1782:
1.18 cvs 1783: <div class="subsection">
1.30 cvs 1784: <h3><a name="sectc3211">Associated elements</a></h3>
1.1 cvs 1785:
1.30 cvs 1786: <p>If associated elements are necessary, they must be declared in a specific
1.18 cvs 1787: section of the structure schema, introduced by the keyword <tt>ASSOC</tt>.
1.1 cvs 1788: Each associated element type is specified like any other structured element.
1789: However, these types must not appear in any other element types of the schema,
1.18 cvs 1790: except in <tt>REFERENCE</tt> rules.</p>
1791: </div>
1.1 cvs 1792:
1.18 cvs 1793: <div class="subsection">
1.30 cvs 1794: <h3><a name="sectc3212">Units</a></h3>
1795:
1796: <p>The <tt>UNITS</tt> section of the structure schema contains the
1797: declarations of the element types which can be used in the external objects
1798: making up parts of the document or in objects of the class defined by the
1799: schema. As with associated elements, these element types are defined just
1800: like other structured element types. They can be used in the other element
1801: types of the schema, but they can also be used in any other rule of the
1802: schema.</p>
1803:
1804: <blockquote class="example">
1805: <p><strong>Example:</strong></p>
1.1 cvs 1806:
1.30 cvs 1807: <p>If references to notes are declared as units:</p>
1808: <pre>UNITS
1.18 cvs 1809: Ref_note = REFERENCE (Note);</pre>
1.30 cvs 1810:
1811: <p>then it is possible to use references to notes in a cell of a table, even
1812: when <tt>Table</tt> is an external structure schema. The <tt>Table</tt>
1813: schema must declare a cell to be a sequence of units, which can then be base
1814: element types (text, for example) or references to notes in the
1815: document.</p>
1816: <pre>Cell = LIST OF (UNITS);</pre>
1.18 cvs 1817: </blockquote>
1818: </div>
1.1 cvs 1819:
1.18 cvs 1820: <div class="subsection">
1.30 cvs 1821: <h3><a name="sectc3213">Skeleton elements</a></h3>
1.1 cvs 1822:
1.30 cvs 1823: <p>When editing a document which contains or must contain external references
1824: to several other documents, it may be necessary to load a large number of
1.1 cvs 1825: documents, simply to see the parts designated by the external references of
1826: the document while editing, or to access the source of included elements. In
1827: this case, the external documents are not modified and it is only necessary to
1828: see the elements of these documents which could be referenced. Because of
1829: this, the editor will suggest that the documents be loaded in ``skeleton''
1830: form. This form contains only the elements of the document explicitly
1.18 cvs 1831: mentioned in the <tt>EXPORT</tt> section of their structure schema and, for
1.1 cvs 1832: these elements, only the part of the contents specified in that section. This
1833: form has the advantage of being very compact, thus requiring very few
1834: resources from the editor. This is also the skeleton form which constitutes
1.18 cvs 1835: the expanded form of <a href="#inclusion">inclusions</a> with partial
1836: expansion.</p>
1.30 cvs 1837:
1838: <p>Skeleton elements must be declared explicitly in the <tt>EXPORT</tt>
1839: section of the structure schema that defines them. This section begins with
1840: the keyword <tt>EXPORT</tt> followed by a comma-separated list of the element
1.1 cvs 1841: types which must appear in the skeleton form and ending with a semicolon.
1.18 cvs 1842: These types must have been previously declared in the schema.</p>
1.30 cvs 1843:
1844: <p>For each skeleton element type, the part of the contents which is loaded by
1.1 cvs 1845: the editor, and therefore displayable, can be specified by putting the keyword
1.18 cvs 1846: <tt>WITH</tt> and the name of the contained element type to be loaded after
1.1 cvs 1847: the name of the skeleton element type. In this case only that named element,
1848: among all the elements contained in the exportable element type, will be
1.18 cvs 1849: loaded. If the <tt>WITH</tt> is absent, the entire contents of the skeleton
1.1 cvs 1850: element will be loaded by the editor. If instead, it is better that the
1851: skeleton form not load the contents of a particular element type, the keyword
1.18 cvs 1852: <tt>WITH</tt> must be followed by the word <tt>Nothing</tt>.</p>
1853: <pre> [ 'EXPORT' SkeletonSeq ]
1.1 cvs 1854:
1.30 cvs 1855: SkeletonSeq = SkelElem < ',' SkelElem > ';' .
1.1 cvs 1856: SkelElem = ElemID [ 'WITH' Contents ] .
1.18 cvs 1857: Contents = 'Nothing' / ElemID [ ExtStruct ] .</pre>
1.30 cvs 1858:
1.18 cvs 1859: <blockquote class="example">
1.30 cvs 1860: <p><strong>Example:</strong></p>
1861:
1862: <p>Suppose that, in documents of the article class, the element types
1863: Article_title, Figure, Section, Paragraph, and Biblio should appear in the
1864: skeleton form in order to make it easier to create external references to
1865: them from other documents. When loading an article in its skeleton form,
1866: all of these element types will be loaded except for paragraphs, but only
1867: the article title will be loaded in its entirety. For figures, the caption
1868: will be loaded, while for sections, the title will be loaded, and for
1.31 cvs 1869: bibliographic entries, only the title that they contain will be loaded. Note
1870: that bibliographic elements are defined in another structure schema, RefBib.
1.32 cvs 1871: To produce this result, the following declarations should be placed in the
1.31 cvs 1872: Article structure schema:</p>
1.30 cvs 1873: <pre>EXPORT
1.1 cvs 1874: Article_title,
1.5 cvs 1875: Figure With Caption,
1.1 cvs 1876: Section With Section_title,
1877: Paragraph With Nothing,
1.18 cvs 1878: Biblio With Biblio_title(RefBib);</pre>
1879: </blockquote>
1880: </div>
1.1 cvs 1881:
1.18 cvs 1882: <div class="subsection">
1.30 cvs 1883: <h3><a name="sectc3214">Exceptions</a></h3>
1.1 cvs 1884:
1.30 cvs 1885: <p>The behavior of the Thot editor and the actions that it performs are
1.1 cvs 1886: determined by the structure schemas. These actions are applied to all
1887: document and object types in accordance with their generic structure. For
1888: certain object types, such as tables and graphics, these actions are not
1889: sufficient or are poorly adapted and some special actions must be added to or
1890: substituted for certain standard actions. These special actions are called
1.18 cvs 1891: <em>exceptions</em>.</p>
1.30 cvs 1892:
1893: <p>Exceptions only inhibit or modify certain standard actions, but they can be
1.18 cvs 1894: used freely in every structure schema.</p>
1.30 cvs 1895:
1896: <p>Each structure schema can contain a section defining exceptions. It begins
1.18 cvs 1897: with the keyword <tt>EXCEPT</tt> and is composed of a sequence of exception
1.1 cvs 1898: declarations, separated by semicolons. Each declaration of an exception
1899: begins with the name of an element type or attribute followed by a colon. This
1900: indicates the element type or attribute to which the following exceptions
1.18 cvs 1901: apply. When the given element type name is a <a href="#sectd3285">mark
1902: pair</a>, and only in this case, the type name can be preceded by the keyword
1903: <tt>First</tt> or <tt>Second</tt>, to indicate if the exceptions which follow
1.1 cvs 1904: are associated with the first mark of the pair or the second. In the absence
1.18 cvs 1905: of this keyword, the first mark is used.</p>
1.30 cvs 1906:
1907: <p>When placed in an <a href="#sectc322">extension schema</a>, the keyword
1.18 cvs 1908: <tt>EXTERN</tt> indicates that the type name which follows is found in the
1.1 cvs 1909: principal schema (the schema being extended by the extension schema). The
1.18 cvs 1910: exceptions are indicated by a name. They are separated by semicolons.</p>
1911: <pre> [ 'EXCEPT' ExceptSeq ]
1.1 cvs 1912:
1.30 cvs 1913: ExceptSeq = Except ';' < Except ';' > .
1.1 cvs 1914: Except = [ 'EXTERN' ] [ FirstSec ] ExcTypeOrAttr
1915: ':' ExcValSeq .
1916: ExcTypeOrAttr = ElemID / AttrID .
1.30 cvs 1917: ExcValSeq = ExcValue < ',' ExcValue > .
1.19 cvs 1918: ExcValue ='NoCut' / 'NoCreate' / 'NoHMove' /
1919: 'NoVMove' / 'NoHResize' / 'NoVResize' /
1920: 'NoMove' / 'NoResize' / 'MoveResize' /
1921: 'NewWidth' / 'NewHeight' / 'NewHPos' /
1922: 'NewVPos' / 'Invisible' /
1.28 cvs 1923: 'NoSelect' / 'NoSpellCheck' /
1.1 cvs 1924: 'Hidden' / 'ActiveRef' /
1925: 'ImportLine' / 'ImportParagraph' /
1926: 'NoPaginate' / 'ParagraphBreak' /
1.19 cvs 1927: 'PageBreak' / 'PageBreakAllowed' / 'PageBreakPlace' /
1928: 'PageBreakRepetition' / 'PageBreakRepBefore' /
1.9 cvs 1929: 'HighlightChildren' / 'ExtendedSelection' /
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>
2072: <dt>IsDraw, IsTable, IsColHead, IsRow, IsCell</dt>
2073: <dd>These exceptions can only be applied to element types. Elements of a
2074: type to which these exceptions are applied are identified as Draws,
2075: Tables, Colheads, Rows or Cells and specific processing are applied to
2076: them.</dd>
2077: <dt>ColRef</dt>
2078: <dd>This exception can only be applied to attributes of the reference
2079: type. It indicates that this attribute refers to the column head (see
2080: exception IsColHead) which the element belongs to.</dd>
2081: <dt>ColSpan, RowSpan</dt>
1.31 cvs 2082: <dd>These exceptions can only be applied to numeric attributes of cells.
1.30 cvs 2083: They indicate that attribute values give how many columns or rows the
2084: element spans.</dd>
2085: <dt>Shadow</dt>
2086: <dd>This exception can only be applied to element types. Text of elements
2087: of a type to which this exception is applied are displayed and printed
2088: as a set of stars ('*').</dd>
1.18 cvs 2089: </dl>
1.30 cvs 2090:
1.18 cvs 2091: <blockquote class="example">
1.30 cvs 2092: <p><strong>Example:</strong></p>
2093:
2094: <p>Consider a structure schema for object-style graphics which defines the
2095: Graphic_object element type with the associated Height and Weight numeric
2096: attributes. Suppose that we want documents of this class to have the
2097: following qualities:</p>
2098: <ul>
2099: <li>Whenever the width or height of an object is changed using the mouse,
2100: the new values are stored in the object's Width and Height
2101: attributes.</li>
2102: <li>The user should not be able to change the values of the Width and
2103: Height attributes via the Attributes menu of the Thot editor.</li>
2104: </ul>
2105:
2106: <p>The following exceptions will produce this effect.</p>
2107: <pre>STRUCT
1.1 cvs 2108: ...
1.5 cvs 2109: Graphics_object (ATTR Height = Integer; Width = Integer)
1.1 cvs 2110: = GRAPHICS with Height ?= 10, Width ?= 10;
2111: ...
2112: EXCEPT
2113: Height: NewHeight, Invisible;
1.18 cvs 2114: Width: NewWidth, Invisible;</pre>
2115: </blockquote>
2116: </div>
2117: </div>
1.1 cvs 2118:
1.18 cvs 2119: <div class="section">
1.30 cvs 2120: <h2><a name="sectb33">Some examples</a></h2>
1.1 cvs 2121:
1.30 cvs 2122: <p>In order to illustrate the principles of the document model and the syntax
2123: of the S language, this section presents two examples of structure schemas.
2124: One defines a class of documents, the other defines a class of objects.</p>
1.1 cvs 2125:
1.18 cvs 2126: <div class="subsection">
1.30 cvs 2127: <h3><a name="sectc331">A class of documents: articles</a></h3>
1.1 cvs 2128:
1.30 cvs 2129: <p>This example shows a possible structure for articles published in a
2130: journal. Text between braces is comments.</p>
1.18 cvs 2131: <pre>STRUCTURE Article; { This schema defines the Article class }
1.1 cvs 2132: DEFPRES ArticleP; { The default presentation schema is
2133: ArticleP }
2134: ATTR { Global attribute definitions }
2135: WordType = Definition, IndexWord, DocumentTitle;
2136: { A single global attribute is defined, with three values }
2137: STRUCT { Definition of the generic structure }
2138: Article = BEGIN { The Article class has an aggregate
2139: structure }
2140: Title = BEGIN { The title is an aggregate }
2141: French_title =
2142: Text WITH Language='Fran\347ais';
2143: English_title =
2144: Text WITH Language='English';
2145: END;
2146: Authors =
2147: LIST OF (Author
2148: (ATTR Author_type=principal,secondary)
2149: { The Author type has a local attribute }
2150: = BEGIN
2151: Author_name = Text;
2152: Info = Paragraphs ;
2153: { Paragraphs is defined later }
2154: Address = Text;
2155: END
2156: );
2157: Keywords = Text;
2158: { The journal's editor introduces the article
2159: with a short introduction, in French and
2160: in English }
2161: Introduction =
2162: BEGIN
2163: French_intr = Paragraphs WITH
2164: Language='Fran\347ais';
2165: English_intr = Paragraphs WITH
2166: Language='English';
2167: END;
2168: Body = Sections; { Sections are defined later }
2169: { Appendixes are only created on demand }
2170: ? Appendices =
2171: LIST OF (Appendix =
2172: BEGIN
2173: Appendix_Title = Text;
2174: Appendix_Contents = Paragraphs;
2175: END
2176: );
2177: END; { End of the Article aggregate }
2178:
2179: Sections = LIST [2..*] OF (
2180: Section = { At least 2 sections }
2181: BEGIN
2182: Section_title = Text;
2183: Section_contents =
2184: BEGIN
2185: Paragraphs;
2186: Sections; { Sections at a lower level }
2187: END;
2188: END
2189: );
2190:
2191: Paragraphs = LIST OF (Paragraph = CASE OF
2192: Enumeration =
2193: LIST [2..*] OF
2194: (Item = Paragraphs);
2195: Isolated_formula = Formula;
2196: LIST OF (UNIT);
2197: END
2198: );
2199:
2200: ASSOC { Associated elements definitions }
2201:
2202: Figure = BEGIN
1.5 cvs 2203: Figure_caption = Text;
1.1 cvs 2204: Illustration = NATURE;
2205: END;
2206:
2207: Biblio_citation = CASE OF
2208: Ref_Article =
2209: BEGIN
2210: Authors_Bib = Text;
2211: Article_Title = Text;
2212: Journal = Text;
2213: Page_Numbers = Text;
2214: Date = Text;
2215: END;
2216: Ref_Livre =
2217: BEGIN
2218: Authors_Bib; { Defined above }
2219: Book_Title = Text;
2220: Editor = Text;
2221: Date; { Defined above }
2222: END;
2223: END;
2224:
2225: Note = Paragraphs - (Ref_note);
2226:
2227: UNITS { Elements which can be used in objects }
2228:
2229: Ref_note = REFERENCE (Note);
2230: Ref_biblio = REFERENCE (Biblio_citation);
2231: Ref_figure = REFERENCE (Figure);
2232: Ref_formula = REFERENCE (Isolated_formula);
2233:
2234: EXPORT { Skeleton elements }
2235:
2236: Title,
1.5 cvs 2237: Figure with Figure_caption,
1.1 cvs 2238: Section With Section_title;
2239:
1.18 cvs 2240: END { End of the structure schema }</pre>
1.30 cvs 2241:
2242: <p>This schema is very complete since it defines both paragraphs and
1.1 cvs 2243: bibliographic citations. These element types could just as well be defined in
1.18 cvs 2244: other structure schemas, as is the case with the <tt>Formula</tt> class. All
1.1 cvs 2245: sorts of other elements can be inserted into an article, since a paragraph can
2246: contain any type of unit. Similarly, figures can be any class of document or
1.18 cvs 2247: object that the user chooses.</p>
1.30 cvs 2248:
2249: <p>Generally, an article doesn't contain appendices, but it is possible to add
1.1 cvs 2250: them on explicit request: this is the effect of the question mark before the
1.18 cvs 2251: word Appendices.</p>
1.30 cvs 2252:
2253: <p>The Figure, Biblio_citation and Note elements are associated elements.
2254: Thus, they are only used in <tt>REFERENCE</tt> statements.</p>
2255:
2256: <p>Various types of cross-references can be put in paragraphs. They can also
2257: be placed the objects which are part of the article, since the
2258: cross-references are defined as units (<tt>UNITS</tt>).</p>
2259:
2260: <p>There is a single restriction to prevent the creation of Ref_note elements
1.18 cvs 2261: within notes.</p>
1.30 cvs 2262:
2263: <p>It is worth noting that the S language permits the definition of recursive
1.1 cvs 2264: structures like sections: a section can contain other sections (which are thus
2265: at the next lower level of the document tree). Paragraphs are also recursive
2266: elements, since a paragraph can contain an enumeration in which each element
1.18 cvs 2267: (<tt>Item</tt>) is composed of paragraphs.</p>
2268: </div>
1.1 cvs 2269:
1.18 cvs 2270: <div class="subsection">
1.30 cvs 2271: <h3><a name="sectc332">A class of objects: mathematical formulas</a></h3>
1.1 cvs 2272:
1.30 cvs 2273: <p>The example below defines the <tt>Formula</tt> class which is used in
2274: Article documents. This class represents mathematical formulas with a rather
2275: simple structure, but sufficient to produce a correct rendition on the screen
2276: or printer. To support more elaborate operations (formal or numeric
1.1 cvs 2277: calculations), a finer structure should be defined. This class doesn't use any
1.18 cvs 2278: other class and doesn't define any associated elements or units.</p>
2279: <pre>STRUCTURE Formula;
1.1 cvs 2280: DEFPRES FormulaP;
2281:
2282: ATTR
2283: String_type = Function_name, Variable_name;
2284:
2285: STRUCT
2286: Formula = Expression;
2287: Expression = LIST OF (Construction);
2288: Construction = CASE OF
2289: TEXT; { Simple character string }
2290: Index = Expression;
2291: Exponent = Expression;
2292: Fraction =
2293: BEGIN
1.6 cvs 2294: Numerator = Expression;
1.1 cvs 2295: Denominator = Expression;
2296: END;
2297: Root =
2298: BEGIN
2299: ? Order = TEXT;
2300: Root_Contents = Expression;
2301: END;
2302: Integral =
2303: BEGIN
2304: Integration_Symbol = SYMBOL;
2305: Lower_Bound = Expression;
2306: Upper_Bound = Expression;
2307: END;
2308: Triple =
2309: BEGIN
2310: Princ_Expression = Expression;
2311: Lower_Expression = Expression;
2312: Upper_Expression = Expression;
2313: END;
2314: Column = LIST [2..*] OF
2315: (Element = Expression);
2316: Parentheses_Block =
2317: BEGIN
2318: Opening = SYMBOL;
2319: Contents = Expression;
2320: Closing = SYMBOL;
2321: END;
2322: END; { End of Choice Constructor }
1.18 cvs 2323: END { End of Structure Schema }</pre>
1.30 cvs 2324:
2325: <p>This schema defines a single global attribute which allows functions and
1.1 cvs 2326: variables to be distinguished. In the presentation schema, this attribute can
2327: be used to choose between roman (for functions) and italic characters (for
1.18 cvs 2328: variables).</p>
1.30 cvs 2329:
2330: <p>A formula's structure is that of a mathematical expression, which is itself
2331: a sequence of mathematical constructions. A mathematical construction can be
1.1 cvs 2332: either a simple character string, an index, an exponent, a fraction, a root,
2333: etc. Each of these mathematical constructions has a sensible structure which
2334: generally includes one or more expressions, thus making the formula class's
1.18 cvs 2335: structure definition recursive.</p>
1.30 cvs 2336:
2337: <p>In most cases, the roots which appear in the formulas are square roots and
1.1 cvs 2338: their order (2) is not specified. This is why the Order component is marked
2339: optional by a question mark. When explicitly requested, it is possible to add
1.18 cvs 2340: an order to a root, for example for cube roots (order = 3).</p>
1.30 cvs 2341:
2342: <p>An integral is formed by an integration symbol, chosen by the user (simple
1.1 cvs 2343: integral, double, curvilinear, etc.), and two bounds. A more fine-grained
2344: schema would add components for the integrand and the integration variable.
2345: Similarly, the Block_Parentheses construction leaves the choice of opening and
2346: closing symbols to the user. They can be brackets, braces, parentheses,
1.18 cvs 2347: etc.</p>
2348: </div>
2349: </div>
2350: <hr>
2351: </div>
1.1 cvs 2352:
1.18 cvs 2353: <div class="chapter">
2354: <h1><a name="sect4">The P Language</a></h1>
1.1 cvs 2355:
1.18 cvs 2356: <div class="section">
1.30 cvs 2357: <h2><a name="sectb41">Document presentation</a></h2>
1.1 cvs 2358:
1.30 cvs 2359: <p>Because of the model adopted for Thot, the presentation of documents is
1.1 cvs 2360: clearly separated from their structure and content. After having presented
2361: the logical structure of documents, we now detail the principles implemented
1.18 cvs 2362: for their presentation. The concept of <em>presentation</em> encompasses what
1.5 cvs 2363: is often called the page layout, the composition, or the document style. It
1.18 cvs 2364: is the set of operations which display the document on the screen or print it
2365: on paper. Like logical structure, document presentation is defined
2366: generically with the help of a language, called P.</p>
1.1 cvs 2367:
1.18 cvs 2368: <div class="subsection">
1.30 cvs 2369: <h3><a name="sectc411">Two levels of presentation</a></h3>
1.1 cvs 2370:
1.30 cvs 2371: <p>The link between structure and presentation is clear: the logical
2372: organization of a document is used to carry out its presentation, since the
2373: purpose of the presentation is to make evident the organization of the
2374: document. But the presentation is equally dependent on the device used to
2375: render the document. Certain presentation effects, notably changes of font or
2376: character set, cannot be performed on all printers or on all screens. This is
2377: why Thot uses a two-level approach, where the presentation is first described
2378: in abstract terms, without taking into account each particular device, and
2379: then the presentation is realized within the constraints of a given
2380: device.</p>
2381:
2382: <p>Thus, presentation is only described as a function of the structure of the
1.1 cvs 2383: documents and the image that would be produced on an idealized device. For
2384: this reason, presentation descriptions do not refer to any device
1.18 cvs 2385: characteristics: they describe <em>abstract presentations</em> which can be
2386: concretized on different devices.</p>
1.30 cvs 2387:
2388: <p>A presentation description also defines a <em>generic presentation</em>,
2389: since it describes the appearance of a class of documents or objects. This
2390: generic presentation must also be applied to document and object instances,
2391: each conforming to its generic logical structure, but with all the allowances
2392: that were called to mind above: missing elements, constructed elements with
2393: other logical structures, etc.</p>
2394:
2395: <p>In order to preserve the homogeneity between documents and objects,
1.1 cvs 2396: presentation is described with a single set of tools which support the layout
2397: of a large document as well as the composition of objects like a graphical
2398: figure or mathematical formula. This unity of presentation description tools
2399: contrasts with the traditional approach, which focuses more on documents than
2400: objects and thus is based on the usual typographic conventions, such as the
2401: placement of margins, indentations, vertical spaces, line lengths,
1.18 cvs 2402: justification, font changes, etc.</p>
2403: </div>
1.1 cvs 2404:
1.18 cvs 2405: <div class="subsection">
1.30 cvs 2406: <h3><a name="sectc412">Boxes</a></h3>
1.1 cvs 2407:
1.30 cvs 2408: <p>To assure the homogeneity of tools, all presentation in Thot, for documents
2409: as well as for the objects which they contain, is based on the notion of the
1.18 cvs 2410: <em>box</em>, such as was implemented in T<sub><big>E</big></sub>X.</p>
1.30 cvs 2411:
2412: <p>Corresponding to each element of the document is a box, which is the
1.1 cvs 2413: rectangle enclosing the element on the display device (screen or sheet of
1.18 cvs 2414: paper); the outline of this rectangle is not visible, except when a <a
2415: href="#sectc4230a"><tt>ShowBox</tt> rule</a> applies to the element. The sides
2416: of the box are parallel to the sides of the screen or the sheet of paper. By
2417: way of example, a box is associated with a character string, a line of text, a
2418: page, a paragraph, a title, a mathematical formula, or a table cell.</p>
1.30 cvs 2419:
2420: <p>Whatever element it corresponds to, each box possesses four sides and four
1.18 cvs 2421: axes, which we designate as follows (<a href="#boxes">see figure</a>):</p>
2422: <dl>
1.30 cvs 2423: <dt><tt>Top</tt></dt>
2424: <dd>the upper side,</dd>
2425: <dt><tt>Bottom</tt></dt>
2426: <dd>the lower side,</dd>
2427: <dt><tt>Left</tt></dt>
2428: <dd>the left side,</dd>
2429: <dt><tt>Right</tt></dt>
2430: <dd>the right side,</dd>
2431: <dt><tt>VMiddle</tt></dt>
2432: <dd>the vertical axis passing through the center of the box,</dd>
2433: <dt><tt>HMiddle</tt></dt>
2434: <dd>the horizontal axis passing through the center of the box,</dd>
2435: <dt><tt>VRef</tt></dt>
2436: <dd>the vertical reference axis,</dd>
2437: <dt><tt>HRef</tt></dt>
2438: <dd>the horizontal reference axis.</dd>
1.18 cvs 2439: </dl>
2440:
2441: <div class="figure">
2442: <hr>
2443: <pre> Left VRef VMiddle Right
1.1 cvs 2444: : :
2445: Top -----------------------------
2446: | : : |
2447: | : : |
2448: | : : |
2449: | : : |
2450: | : : |
2451: HMiddle ..|...........................|..
2452: | : : |
2453: | : : |
2454: HRef ..|...........................|..
2455: | : : |
2456: | : : |
2457: Bottom -----------------------------
1.18 cvs 2458: : :</pre>
1.30 cvs 2459:
2460: <p align="center"><em><a name="boxes">The sides and axes of
2461: boxes</a><em></em></em></p>
1.18 cvs 2462: <hr>
1.30 cvs 2463: </div>
1.19 cvs 2464:
1.30 cvs 2465: <p>The principal role of boxes is to set the extent and position of the images
2466: of the different elements of a document with respect to each other on the
1.1 cvs 2467: reproduction device. This is done by defining relations between the boxes of
2468: different elements which give relative extents and positions to these
1.18 cvs 2469: boxes.</p>
1.30 cvs 2470:
2471: <p>There are three types of boxes:</p>
1.18 cvs 2472: <ul>
1.30 cvs 2473: <li>boxes corresponding to structural elements of the document,</li>
2474: <li>presentation boxes,</li>
2475: <li>page layout boxes.</li>
1.18 cvs 2476: </ul>
1.30 cvs 2477:
2478: <p><strong>Boxes corresponding to structural elements of the document</strong>
1.1 cvs 2479: are those which linked to each of the elements (base or structured) of the
2480: logical structure of the document. Such a box contains all the contents of
1.18 cvs 2481: the element to which it corresponds (there is an exception: see <a
2482: href="#sectc4220">rules <tt>VertOverflow</tt> and <tt>HorizOverflow</tt></a>).
2483: These boxes form a tree-like structure, identical to that of the structural
2484: elements to which they correspond. This tree expresses the inclusion
2485: relationships between the boxes: a box includes all the boxes of its subtree.
2486: On the other hand, there are no predefined rules for the relative positions of
2487: the included boxes. If they are at the same level, they can overlap, be
2488: contiguous, or be disjoint. The rules expressed in the generic presentation
2489: specify their relative positions.</p>
1.30 cvs 2490:
2491: <p><strong>Presentation boxes</strong> represent elements which are not found
2492: in the logical structure of the document but which are added to meet the needs
2493: of presentation. These boxes are linked to the elements of the logical
2494: structure that are best suited to bringing them out. For example, they are
2495: used to add the character string ``Summary:'' before the summary in the
2496: presentation of a report or to represent the fraction bar in a formula, or
2497: also to make the title of a field in a form appear. These elements have no
2498: role in the logical structure of the document: the presence of a Summary
2499: element in the document does not require the creation of another structural
2500: object to hold the word ``Summary''. Similarly, if a Fraction element contains
2501: both a Numerator element and a Denominator element, the fraction bar has no
2502: purpose structurally. On the other hand, these elements of the presentation
2503: are important for the reader of the reproduced document or for the user of an
1.1 cvs 2504: editor. This is why they must appear in the document's image. It is the
2505: generic presentation which specifies the presentation boxes to add by
2506: indicating their content (a base element for which the value is specified) and
2507: the position that they must take in the tree of boxes. During editing, these
1.18 cvs 2508: boxes cannot be modified by the user.</p>
1.30 cvs 2509:
2510: <p><strong>Page layout boxes</strong> are boxes created implicitly by the page
1.1 cvs 2511: layout rules. These rules indicate how the contents of a structured element
2512: must be broken into lines and pages. In contrast to presentation boxes, these
2513: line and page boxes do not depend on the logical structure of the document,
1.18 cvs 2514: but rather on the physical constraints of the output devices: character size,
2515: height and width of the window on the screen or of the sheet of paper.</p>
2516: </div>
1.1 cvs 2517:
1.18 cvs 2518: <div class="subsection">
1.30 cvs 2519: <h3><a name="sectc413">Views and visibility</a></h3>
1.1 cvs 2520:
1.30 cvs 2521: <p>One of the operations that one might wish to perform on a document is to
2522: view it is different ways. For this reason, it is possible to define several
1.18 cvs 2523: <em>views</em> for the same document, or better yet, for all documents of the
1.1 cvs 2524: same class. A view is not a different presentation of the document, but
2525: rather a filter which only allows the display of certain parts of the
2526: document. For example, it might be desirable to see only the titles of
2527: chapters and sections in order to be able to move rapidly through the
2528: document. Such a view could be called a ``table of contents''. It might also
2529: be desirable to see only the mathematical formulas of a document in order to
2530: avoid being distracted by the non-mathematical aspects of the document. A
1.18 cvs 2531: ``mathematics'' view could provide this service.</p>
1.30 cvs 2532:
2533: <p>Views, like presentation, are based on the generic logical structure. Each
1.1 cvs 2534: document class, and each generic presentation, can be provided with views
2535: which are particularly useful for that class or presentation. For each view,
1.18 cvs 2536: the <em>visibility</em> of elements is defined, indicated whether or not the
1.1 cvs 2537: elements must be presented to the user. The visibility is calculated as a
2538: function of the type of the elements or their hierarchical position in the
2539: structure of the document. Thus, for a table of contents, all the ``Chapter
2540: Title'' and ``Section Title'' elements are made visible. However, the
2541: hierarchical level could be used to make the section titles invisible below a
2542: certain threshold level. By varying this threshold, the granularity of the
2543: view can be varied. In the ``mathematics'' view, only Formula elements would
1.18 cvs 2544: be made visible, no matter what their hierarchical level.</p>
1.30 cvs 2545:
2546: <p>Because views are especially useful for producing a synthetic image of the
1.1 cvs 2547: document, it is necessary to adapt the presentation of the elements to the
2548: view in which they appear. For example, it is inappropriate to have a page
2549: break before every chapter title in the table of contents. Thus, generic
2550: presentations take into account the possible views and permit each element
1.18 cvs 2551: type's presentation to vary according the view in which its image appears.</p>
1.30 cvs 2552:
2553: <p><a name="views">Views</a> are also used, when editing documents, to display
1.1 cvs 2554: the associated elements. So, in addition to the primary view of the document,
2555: there can be a ``notes'' view and a ``figures'' view which contain,
2556: respectively, the associated elements of the Note and Figure types. In this
2557: way, it is possible to see simultaneously the text which refers to these
2558: elements and the elements themselves, even if they will be separated when
1.18 cvs 2559: printed.</p>
2560: </div>
1.1 cvs 2561:
1.18 cvs 2562: <div class="subsection">
1.30 cvs 2563: <h3><a name="sectc414">Pages</a></h3>
1.1 cvs 2564:
1.30 cvs 2565: <p>Presentation schemas can be defined which display the document as a long
1.1 cvs 2566: scroll, without page breaks. This type of schema is particularly well-suited
2567: to the initial phase of work on a document, where jumps from page to page
2568: would hinder composing and reading the document on a screen. In this case,
2569: the associated elements (such as notes), which are normally displayed in the
2570: page footer, are presented in a separate window. But, once the document is
2571: written, it may be desirable to display the document on the screen in the same
2572: manner in which it will be printed. So, the presentation schema must define
1.18 cvs 2573: pages.</p>
1.30 cvs 2574:
2575: <p>The P language permits the specification of the dimensions of pages as well
2576: as their composition. It is possible to generate running titles, page
2577: numbers, zones at the bottom of the page for notes, etc. The editor follows
2578: this model and inserts page break marks in the document which are used during
2579: printing, insuring that the pages on paper are the same as on the screen.</p>
2580:
2581: <p>Once a document has been edited with a presentation schema defining pages,
2582: it contains page marks. But it is always possible to edit the document using
2583: a schema without pages. In this case, the page marks are simply ignored by
2584: the editor. They are considered again as soon as a schema with pages is used.
1.18 cvs 2585: Thus, the user is free to choose between schemas with and without pages.</p>
1.30 cvs 2586:
2587: <p>Thot treats the page break, rather than the page itself, as a box. This
2588: page break box contains all the elements of one page's footer, a rule marking
2589: the edge of this page, and all the elements of the next page's header. The
1.1 cvs 2590: elements of the header and footer can be running titles, page number,
2591: associated elements (notes, for example), etc. All these elements, as well as
2592: their content and graphical appearance, are defined by the generic
1.18 cvs 2593: presentation.</p>
2594: </div>
1.1 cvs 2595:
1.18 cvs 2596: <div class="subsection">
1.30 cvs 2597: <h3><a name="sectc415">Numbering</a></h3>
1.1 cvs 2598:
1.30 cvs 2599: <p>Many elements are numbered in documents: pages, chapters, sections,
2600: formulas, theorems, notes, figures, bibliographic references, exercises,
2601: examples, lemmas, etc. Because Thot has a notion of logical structure, all of
2602: these numbers (with the exception of pages) are redundant with information
2603: implicit in the logical structure of the document. Such numbers are simply a
2604: way to make the structure of the document more visible. So, they are part of
2605: the document's presentation and are calculated by the editor from the logical
1.1 cvs 2606: structure. The structure does not contain numbers as such; it only defines
2607: relative structural positions between elements, which serve as ordering
1.18 cvs 2608: relations on these elements.</p>
1.30 cvs 2609:
2610: <p>If the structure schema defines the body of a document as a sequence of at
1.18 cvs 2611: least two chapters:</p>
2612: <pre>Body = LIST [2..*] OF Chapter;</pre>
1.30 cvs 2613:
2614: <p>the sequence defined by the list constructor is ordered and each chapter
2615: can be assigned a number based on its rank in the Body list. Therefore, all
1.18 cvs 2616: elements contained in lists a the structure of a document can be numbered, but
2617: they are not the only ones. The tree structure induced by the aggregate,
2618: list, and choice constructors (excluding references) defines a total order on
2619: the elements of the document's primary structure. So, it is possible to
2620: define a numbering which uses this order, filtering elements according to
2621: their type so that only certain element types are taken into account in the
2622: numbering. In this way, it possible to number all the theorems and lemmas of
2623: a chapter in the same sequence of numbers, even when they are not part of the
2624: same list constructor and appear at different levels of the document's tree.
2625: By changing the filter, they can be numbered separately: one sequence of
2626: numbers for theorems, another for the lemmas.</p>
1.30 cvs 2627:
2628: <p>Associated elements pose a special problem, since they are not part of the
1.1 cvs 2629: document's primary structure, but are attached only by references, which
2630: violate the total order of the document. Then, these associated elements are
2631: frequently numbered, precisely because the number is an effective way to
2632: visualize the reference. In order to resolve this problem, Thot implicitly
2633: defines a list constructor for each type of associated element, gathering
2634: together (and ordering) these elements. Thus, the associated elements can be
1.18 cvs 2635: numbered by type.</p>
1.30 cvs 2636:
2637: <p>Since they are calculated from the document's logical structure and only
2638: for the needs of the presentation, numbers are presentation elements,
2639: described by presentation boxes, just like the fraction bar or the word
2640: ``Summary''. Nevertheless, numbers differ from these other boxes because their
2641: content varies from instance to instance, even though they are of the same
2642: type, whereas all fraction bars are horizontal lines and the same word
2643: ``Summary'' appears at the head of every document's summary.</p>
1.18 cvs 2644: </div>
1.1 cvs 2645:
1.18 cvs 2646: <div class="subsection">
1.34 ! cvs 2647: <h3><a name="sectc416">Presentation properties</a></h3>
1.1 cvs 2648:
1.34 ! cvs 2649: <p>The principal properties which determine document presentation are the
1.18 cvs 2650: <em>positions</em> and <em>dimensions</em> of boxes, the <em>font</em>, the
2651: <em>style</em>, the <em>size</em>, the <em>underlining</em> and the
1.34 ! cvs 2652: <em>color</em> of their content. From these properties, and some others of
! 2653: less importance, it is possible to represent the usual typographic properties
! 2654: for the textual parts of the document. These same properties can be used to
1.1 cvs 2655: describe the geometry of the non-textual elements, even though they are
1.18 cvs 2656: two-dimensional elements unlike the text, which is linear.</p>
1.30 cvs 2657:
2658: <p>As we have already seen, the positions of the boxes always respect the
2659: rule of enclosure: a box in the tree encloses all the boxes of the next lower
1.34 ! cvs 2660: level which are attached to it. The positional properties permit the
1.30 cvs 2661: specification of the position of each box in relation to the enclosing box or
2662: to its sibling boxes (boxes directly attached to the same enclosing box in the
2663: tree of boxes).</p>
2664:
1.34 ! cvs 2665: <p>The presentation properties also provide control over the dimensions of the
1.1 cvs 2666: boxes. The dimensions of a box can depend either on its content or on its
2667: context (its sibling boxes and the enclosing box). Each dimension (height or
1.18 cvs 2668: width) can be defined independently of the other.</p>
1.30 cvs 2669:
1.34 ! cvs 2670: <p>Because of the position and dimension properties, it is possible to do the
1.1 cvs 2671: same things that are normally done in typography by changing margins, line
2672: lengths, and vertical or horizontal skips. This approach can also align or
1.18 cvs 2673: center elements and groups of elements.</p>
1.30 cvs 2674:
1.34 ! cvs 2675: <p>In contrast to the position and dimension properties, the font, style,
1.30 cvs 2676: size, underlining, and color do not concern the box itself (the rectangle
1.34 ! cvs 2677: delimiting the element), but its content. These properties indicate the
1.30 cvs 2678: typographic attributes which must be applied to the text contained in the box,
2679: and by extension, to all base elements.</p>
2680:
1.34 ! cvs 2681: <p>For text, the font property is used to change the family of characters
1.1 cvs 2682: (Times, Helvetica, Courier, etc.); the style is used to obtain italic or
2683: roman, bold or light characters; the size determines the point size of the
2684: characters; underlining defines the type and thickness of the lines drawn
1.18 cvs 2685: above, below, or through the characters.</p>
1.30 cvs 2686:
1.34 ! cvs 2687: <p>For graphics, the line style property can be either solid, dotted, or
! 2688: dashed; the line thickness property controls the width of the lines; the fill
! 2689: pattern property determines how closed geometric figures must be filled.</p>
1.30 cvs 2690:
1.34 ! cvs 2691: <p>While some of the properties which determine the appearance of a box's
1.1 cvs 2692: contents make sense only for one content type (text or graphic), other
1.34 ! cvs 2693: properties apply to all content types: these are the color properties. These
1.18 cvs 2694: indicate the color of lines and the background color.</p>
2695: </div>
2696: </div>
1.1 cvs 2697:
1.18 cvs 2698: <div class="section">
1.30 cvs 2699: <h2><a name="sectb42">Presentation description language</a></h2>
2700:
1.34 ! cvs 2701: <p>A generic presentation defines the values of presentation properties (or
1.30 cvs 2702: the way to calculate those values) for a generic structure, or more precisely,
2703: for all the element types and all the global and local attributes defined in
1.34 ! cvs 2704: that generic structure. This definition of the presentation properties is
1.30 cvs 2705: made with the P language. A program written in this language, that is a
2706: generic presentation expressed in P, is call a <em>presentation schema</em>.
2707: This section describes the syntax and semantics of the language, using the
2708: same <a href="#sectc321">meta-language</a> as was used for the definition of
2709: the S language.</p>
1.1 cvs 2710:
1.30 cvs 2711: <p>Recall that it is possible to write many different presentation schemas for
1.1 cvs 2712: the same class of documents or objects. This allows users to choose for a
2713: document the graphical appearance which best suits their type of work or
1.18 cvs 2714: their personal taste.</p>
1.1 cvs 2715:
1.18 cvs 2716: <div class="subsection">
1.30 cvs 2717: <h3><a name="sectc421">The organization of a presentation schema</a></h3>
1.1 cvs 2718:
1.30 cvs 2719: <p>A presentation schema begins with the word <tt>PRESENTATION</tt> and ends
2720: with the word <tt>END</tt>. The word <tt>PRESENTATION</tt> is followed by the
2721: name of the generic structure to which the presentation will be applied. This
2722: name must be the same as that which follows the keyword <tt>STRUCTURE</tt> in
2723: the structure schema associated with the presentation schema.</p>
2724:
2725: <p>After this declaration of the name of the structure, the following sections
1.18 cvs 2726: appear (in order):</p>
2727: <ul>
1.30 cvs 2728: <li>Declarations of
2729: <ul>
2730: <li>all views,</li>
2731: <li>printed views,</li>
2732: <li>counters,</li>
2733: <li>presentation constants,</li>
2734: <li>variables,</li>
2735: </ul>
2736: </li>
2737: <li>default presentation rules,</li>
2738: <li>presentation box and page layout box definitions,</li>
2739: <li>presentation rules for structured elements,</li>
2740: <li>presentation rules for attributes,</li>
2741: <li>rules for transmitting values to attributes of included documents.</li>
1.18 cvs 2742: </ul>
1.30 cvs 2743:
2744: <p>Each of these sections is introduced by a keyword which is followed by a
1.18 cvs 2745: sequence of declarations. Every section is optional.</p>
2746: <pre> SchemaPres ='PRESENTATION' ElemID ';'
1.1 cvs 2747: [ 'VIEWS' ViewSeq ]
2748: [ 'PRINT' PrintViewSeq ]
2749: [ 'COUNTERS' CounterSeq ]
2750: [ 'CONST' ConstSeq ]
2751: [ 'VAR' VarSeq ]
2752: [ 'DEFAULT' ViewRuleSeq ]
2753: [ 'BOXES' BoxSeq ]
2754: [ 'RULES' PresentSeq ]
2755: [ 'ATTRIBUTES' PresAttrSeq ]
2756: [ 'TRANSMIT' TransmitSeq ]
2757: 'END' .
1.18 cvs 2758: ElemID = NAME .</pre>
2759: </div>
1.1 cvs 2760:
1.18 cvs 2761: <div class="subsection">
1.30 cvs 2762: <h3><a name="sectc422">Views</a></h3>
1.1 cvs 2763:
1.30 cvs 2764: <p>Each of the possible views must be declared in the presentation schema. As
1.18 cvs 2765: has <a href="#views">already been described</a>, the presentation rules for an
1.1 cvs 2766: element type can vary according to the view in which the element appears. The
2767: name of the view is used to designate the view to which the presentation rules
1.18 cvs 2768: apply (see the <a href="#inkeyword"><tt>IN</tt> instruction</a>). The
1.1 cvs 2769: definition of the view's contents are dispersed throughout the presentation
2770: rules attached to the different element types and attributes. The
1.18 cvs 2771: <tt>VIEWS</tt> section is simply a sequence of view names separated by commas
2772: and terminated by a semi-colon.</p>
1.30 cvs 2773:
2774: <p>One of the view names (and only one) can be followed by the keyword
1.18 cvs 2775: <tt>EXPORT</tt>. This keyword identifies the view which presents the members
2776: of the document class in <a href="#sectc3213">skeleton form</a>. The
2777: graphical appearance and the content of this view is defined just as with
2778: other views, but it is useless to specify presentation rules concerning this
2779: view for the elements which are not loaded in the skeleton form.</p>
1.30 cvs 2780:
2781: <p>It is not necessary to declare any views; in this case there is a single
1.1 cvs 2782: unnamed view. If many views are declared, the first view listed is considered
2783: the principal view. The principal view is the one to which all rules that are
1.18 cvs 2784: not preceded by an indication of a view will apply (see the <a
2785: href="#inkeyword">instruction <tt>IN</tt></a>).</p>
1.30 cvs 2786:
2787: <p>The principal view is the the one which the editor presents on the screen
2788: when the user asks to create or edit a document. Thus, it makes sense to put
2789: the most frequently used view at the head of the list. But if the structure
1.18 cvs 2790: schema contains <a href="#sectc3213">skeleton elements</a> and is loaded in
2791: its skeleton form, the view whose name is followed by the keyword
2792: <tt>EXPORT</tt> will be opened and no other views can be opened.</p>
2793: <pre> 'VIEWS' ViewSeq
1.1 cvs 2794: ViewSeq = ViewDeclaration
1.30 cvs 2795: < ',' ViewDeclaration > ';' .
1.1 cvs 2796: ViewDeclaration = ViewID [ 'EXPORT' ] .
1.18 cvs 2797: ViewID = NAME .</pre>
1.30 cvs 2798:
1.18 cvs 2799: <blockquote class="example">
1.30 cvs 2800: <p><strong>Example:</strong></p>
2801:
2802: <p>When editing a report, it might be useful have views of the table of
2803: contents and of the mathematical formulas, in addition to the principal view
2804: which shows the document in its entirety. To achieve this, a presentation
2805: schema for the Report class would have the following <tt>VIEWS</tt>
2806: section:</p>
2807: <pre>VIEWS
1.18 cvs 2808: Full_text, Table_of_contents, Formulas;</pre>
1.30 cvs 2809:
2810: <p>The contents of these views are specified in the presentation rules of
2811: the schema.</p>
1.18 cvs 2812: </blockquote>
2813: </div>
1.1 cvs 2814:
1.18 cvs 2815: <div class="subsection">
1.30 cvs 2816: <h3><a name="sectc423">Print Views</a></h3>
1.1 cvs 2817:
1.30 cvs 2818: <p>When editing a document, each view is presented in a different window. In
1.18 cvs 2819: addition to the views specified by the <tt>VIEWS</tt> instruction, the user
1.1 cvs 2820: can display the associated elements with one window for each type of
1.18 cvs 2821: associated element.</p>
1.30 cvs 2822:
2823: <p>When printing a document, it is possible to print any number of views,
2824: chosen from among all the views which the editor can display (views in the
2825: strict sense or associated elements). Print views, as well as the order in
2826: which they must be printed, are indicated by the <tt>PRINT</tt> instruction.
2827: It appears after the <tt>VIEWS</tt> instruction and is formed of the keyword
1.18 cvs 2828: <tt>PRINT</tt> followed by the ordered list of print view names. The print
1.1 cvs 2829: view names are separated by commas and followed by a semi-colon. A print view
1.18 cvs 2830: name is either a view name declared in the <tt>VIEWS</tt> instruction or the
1.1 cvs 2831: name of an associated element type (with an ``s'' added to the end). The
1.18 cvs 2832: associated element must have been declared in the <tt>ASSOC</tt> section of
2833: the structure schema.</p>
2834: <pre> 'PRINT' PrintViewSeq
1.30 cvs 2835: PrintViewSeq = PrintView < ',' PrintView > ';' .
1.18 cvs 2836: PrintView = ViewID / ElemID .</pre>
1.30 cvs 2837:
2838: <p>If the <tt>PRINT</tt> instruction is absent, the printing program will
2839: print only the principal view (the first view specified by the <tt>VIEWS</tt>
1.18 cvs 2840: instruction or the single, unnamed view when there is no <tt>VIEWS</tt>
2841: instruction).</p>
1.30 cvs 2842:
1.18 cvs 2843: <blockquote class="example">
1.30 cvs 2844: <p><strong>Example:</strong></p>
2845:
2846: <p>Consider a Report presentation using the view declarations from the
2847: preceding example. Suppose we want to print the full text and table of
2848: contents views, but not the Formulas view, which is only useful when
2849: editing. In addition, suppose that we also want to print the bibliographic
2850: citations, which are associated elements (of type <tt>Citation</tt>). A
2851: sensible printing order would be to print the full text then the
2852: bibliography and finally the table of contents. To obtain this result when
2853: printing, the presentation schema would say:</p>
2854: <pre>PRINT
1.18 cvs 2855: Full_text, Citations, Table_of_contents;</pre>
2856: </blockquote>
2857: </div>
2858:
2859: <div class="subsection">
1.30 cvs 2860: <h3><a name="sectc424">Counters</a></h3>
1.18 cvs 2861:
1.30 cvs 2862: <p>A presentation has a <em>counter</em> for each type of number in the
1.1 cvs 2863: presentation. All counters, and therefore all types of numbers, used in the
1.18 cvs 2864: schema must be declared after the <tt>COUNTERS</tt> keyword.</p>
1.30 cvs 2865:
2866: <p>Each counter declaration is composed of a name identifying the counter
1.1 cvs 2867: followed by a colon and the counting function to be applied to the counter.
1.18 cvs 2868: The counter declaration ends with a semi-colon.</p>
1.30 cvs 2869:
2870: <p>The counting function indicates how the counter values will be calculated.
1.16 cvs 2871: Three types of counting functions are available. The first type is used to
2872: count the elements of a list or aggregate: it assigns to the counter the rank
1.18 cvs 2873: of the element in the list or aggregate. More precisely, the function</p>
2874: <pre>RANK OF ElemID [ LevelAsc ] [ INIT AttrID ]
2875: [ 'REINIT' AttrID ]</pre>
1.30 cvs 2876:
2877: <p>indicates that when an element creates, by a creation rule (see the <a
1.18 cvs 2878: href="#sectc4232"><tt>Create</tt> instructions</a>), a presentation box
1.5 cvs 2879: containing the counter value, this value is the rank of the creating element,
1.18 cvs 2880: if it is of type <tt>ElemID</tt>, otherwise the rank of the first element of
2881: type <tt>ElemID</tt> which encloses the creating element in the logical
2882: structure of the document.</p>
1.30 cvs 2883:
2884: <p>The type name can be preceded by a star in the special case where the
1.18 cvs 2885: structure schema defines an element of whose <tt>ElemID</tt> is the same as
2886: that of an <a href="#sectd3284">inclusion</a> without expansion or with
2887: partial expansion. To resolve this ambiguity, the <tt>ElemID</tt> alone
2888: refers to the type defined in the structure schema while the <tt>ElemID</tt>
2889: preceded by a star refers to the included type.</p>
1.30 cvs 2890:
2891: <p>The type name <tt>ElemID</tt> can be followed by an integer. That number
1.1 cvs 2892: represents the relative level, among the ancestors of the creating element, of
1.18 cvs 2893: the element whose rank is asked. If that relative level <i>n</i> is unsigned,
2894: the <i>n</i><sup>th</sup> element of type <tt>ElemID</tt> encountered when
1.1 cvs 2895: travelling the logical structure from the root to the creating element is
1.16 cvs 2896: taken into account. If the relative level is negative, the logical structure
2897: is travelled in the other direction, from the creating element to the
1.18 cvs 2898: root.</p>
1.30 cvs 2899:
2900: <p>The function can end with the keyword <tt>INIT</tt> followed by the name of
2901: a numeric attribute (and only a numeric attribute). Then, the rank of the
2902: first element of the list or aggregate is considered to be the value of this
1.1 cvs 2903: attribute, rather than the default value of 1, and the rank of the other
2904: elements is shifted accordingly. The attribute which determines the initial
1.18 cvs 2905: value is searched on the element itself and on its ancestors.</p>
1.30 cvs 2906:
2907: <p>The function can end with the keyword <tt>REINIT</tt> followed by the name
2908: of a numeric attribute (and only a numeric attribute). Then, if an element to
2909: be counted has this attribute, the counter value for this element is the
1.1 cvs 2910: attribute value and the following elements are numbered starting from this
1.18 cvs 2911: value.</p>
1.30 cvs 2912:
2913: <p>When the <tt>RANK</tt> function is written</p>
1.18 cvs 2914: <pre>RANK OF Page [ ViewID ] [ INIT AttrID ]</pre>
1.30 cvs 2915:
2916: <p>(<tt>Page</tt>is a keyword of the P language), the counter takes as its
2917: value the number of the page on which the element which creates the
2918: presentation box containing the number appears. This is done as if the pages
2919: of the document form a list for each view. The counter only takes into
2920: account the pages of the relevant view, that is the view displaying the
2921: presentation box whose contents take the value of the number. However, if the
2922: keyword <tt>Page</tt> is followed by the name of a view (between parentheses),
2923: it is the pages of that view that are taken into account. As in the preceding
2924: form, the <tt>RANK</tt> function applied to pages can end with the
2925: <tt>INIT</tt> keyword followed by the name of a numeric attribute which sets
2926: the value of the first page's number. This attribute must be a local
2927: attribute of the document itself, and not of one of its components.</p>
2928:
2929: <p>The second counting function is used to count the occurrences of a certain
1.18 cvs 2930: element type in a specified context. The instruction</p>
2931: <pre>SET n ON Type1 ADD m ON Type2 [ INIT AttrID ]</pre>
1.30 cvs 2932:
2933: <p>says that when the document is traversed from beginning to end (in the
2934: order induced by the logical structure), the counter is assigned the value
1.18 cvs 2935: <tt>n</tt> each time an element of type <tt>Type1</tt> is encountered, no
2936: matter what the current value of the counter, and the value <tt>m</tt> is
2937: added to the current value of the counter each time an element of type
2938: <tt>Type2</tt> is encountered.</p>
1.30 cvs 2939:
2940: <p>As with the <tt>RANK</tt> function, the type names can be preceded by a
2941: star to resolve the ambiguity of included elements.</p>
2942:
2943: <p>If the function ends with the keyword <tt>INIT</tt> followed by the name of
2944: an attribute and if the document possesses this attribute, the value of this
1.18 cvs 2945: attribute is used in place of <tt>n</tt>. The attribute must be numeric. It
2946: is searched on the element itself and on its ancestors.</p>
1.30 cvs 2947:
2948: <p>This function can also be used with the <tt>Page</tt> keyword in the place
2949: of <tt>Type1</tt> or <tt>Type2</tt>. In the first case, the counter is
1.18 cvs 2950: reinitialized on each page with the value <tt>n</tt>, while in the second
2951: case, it is incremented by <tt>m</tt> on each page. As with the preceding
2952: counting function, the word <tt>Page</tt> can be followed by a name between
1.1 cvs 2953: parentheses. In this case, the name specifies a view whose pages are taken
1.18 cvs 2954: into account.</p>
1.30 cvs 2955:
2956: <p>The definition of a counter can contain several <tt>SET</tt> functions and
1.18 cvs 2957: several <tt>ADD</tt> functions, each with a different value. The total number
2958: of counting functions must not be greater than 6.</p>
1.30 cvs 2959:
2960: <p>The third counting function is used to count the elements of a certain type
1.16 cvs 2961: encountered when travelling from the creating element to the root of the
2962: logical structure. The creating element is included if it is of that type.
1.18 cvs 2963: That function is written</p>
2964: <pre>RLEVEL OF Type</pre>
1.30 cvs 2965:
2966: <p>where <tt>Type</tt> represents the type of the elements to be counted.</p>
2967:
2968: <p>The formal definition of counter declarations is:</p>
1.18 cvs 2969: <pre> 'COUNTERS' CounterSeq
1.30 cvs 2970: CounterSeq = Counter < Counter > .
1.1 cvs 2971: Counter = CounterID ':' CounterFunc ';' .
2972: CounterID = NAME .
2973: CounterFunc = 'RANK' 'OF' TypeOrPage [ SLevelAsc ]
1.16 cvs 2974: [ 'INIT' AttrID ] [ 'REINIT' AttrID ] /
1.30 cvs 2975: SetFunction < SetFunction >
2976: AddFunction < AddFunction >
1.16 cvs 2977: [ 'INIT' AttrID ] /
2978: 'RLEVEL' 'OF' ElemID .
1.1 cvs 2979: SLevelAsc = [ '-' ] LevelAsc .
2980: LevelAsc = NUMBER .
2981: SetFunction = 'SET' CounterValue 'ON' TypeOrPage .
2982: AddFunction = 'ADD' CounterValue 'ON' TypeOrPage .
2983: TypeOrPage = 'Page' [ '(' ViewID ')' ] /
1.16 cvs 2984: [ '*' ] ElemID .
1.18 cvs 2985: CounterValue = NUMBER .</pre>
1.30 cvs 2986:
1.18 cvs 2987: <blockquote class="example">
1.30 cvs 2988: <p><strong>Example:</strong></p>
2989:
2990: <p>If the body of a chapter is defined as a sequence of sections in the
2991: structure schema:</p>
2992: <pre>Chapter_body = LIST OF (Section =
1.1 cvs 2993: BEGIN
2994: Section_Title = Text;
2995: Section_Body = Paragraphs;
2996: END
1.18 cvs 2997: );</pre>
1.30 cvs 2998:
2999: <p>the section counter is declared:</p>
3000: <pre>SectionCtr : RANK OF Section;</pre>
3001:
3002: <p>and the display of the section number before the section title is
3003: obtained by a <a href="#sectc4232"><tt>CreateBefore</tt> rule</a> attached
3004: the <tt>Section_Title</tt> type, which creates a presentation box whose
3005: content is the value of the <tt>SectionCtr</tt> counter (see the <a
3006: href="#sectc4231"><tt>Content</tt> instruction</a>).</p>
3007:
3008: <p>In order to number the formulas separately within each chapter, the
3009: formula counter is declared:</p>
3010: <pre>FormulaCtr : SET 0 ON Chapter ADD 1 ON Formula;</pre>
3011:
3012: <p>and the display of the formula number in the right margin, alongside each
3013: formula, is obtained by a <tt>CreateAfter</tt> instruction attached to the
3014: <tt>Formula</tt> type, which creates a presentation box whose content is the
3015: value of the <tt>FormulaCtr</tt> counter.</p>
3016:
3017: <p>To number the page chapter by chapter, with the first page of each
3018: chapter having the number 1, the counter definition would be</p>
3019: <pre>ChapterPageCtr : SET 0 ON Chapter ADD 1 ON Page;</pre>
3020:
3021: <p>If there is also a chapter counter</p>
3022: <pre>ChapterCtr : RANK OF Chapter;</pre>
3023:
3024: <p>the <a href="#sectc4231">content</a> of a presentation box created at the
3025: top of each page could be defined as:</p>
3026: <pre>Content : (VALUE(ChapterCtr, URoman) TEXT '-'
1.18 cvs 3027: VALUE(ChapterPageCtr, Arabic));</pre>
1.30 cvs 3028:
3029: <p>Thus, the presentation box contains the number of the chapter in
3030: upper-case roman numerals followed by a hyphen and the number of the page
3031: within the chapter in arabic numerals.</p>
1.18 cvs 3032: </blockquote>
1.30 cvs 3033:
1.18 cvs 3034: <blockquote class="example">
1.30 cvs 3035: <p><strong>Example:</strong></p>
3036:
3037: <p>To count tables and figures together in a document of the chapter type, a
3038: counter could be defined using:</p>
3039: <pre>CommonCtr : SET 0 ON Chapter ADD 1 ON Table
1.18 cvs 3040: ADD 1 ON Figure;</pre>
3041: </blockquote>
3042: </div>
1.1 cvs 3043:
1.18 cvs 3044: <div class="subsection">
1.30 cvs 3045: <h3><a name="sectc425">Presentation constants</a></h3>
1.1 cvs 3046:
1.30 cvs 3047: <p>Presentation constants are used in the definition of the content of
1.18 cvs 3048: presentation boxes. This content is used in <a href="#sectc426">variable
3049: definitions</a> and in the <a href="#sectc4231"><tt>Content</tt> rule</a>. The
1.1 cvs 3050: only presentation constants which can be used are character strings,
1.2 cvs 3051: mathematical symbols, graphical elements, and pictures, that is to say, base
1.18 cvs 3052: elements.</p>
1.30 cvs 3053:
3054: <p>Constants can be defined directly in the variables or presentation boxes
1.18 cvs 3055: (<tt>Content</tt> rule) which use them. But it is only necessary them to
1.1 cvs 3056: declare once, in the constant declaration section, even though they are used
3057: in many variables or boxes. Thus, each declared constant has a name, which
3058: allows it to be designated whenever it is used, a type (one of the four base
3059: types) and a value (a character string or a single character for mathematical
1.18 cvs 3060: symbols and graphical elements).</p>
1.30 cvs 3061:
3062: <p>The constant declarations appear after the keyword <tt>CONST</tt>. Each
1.1 cvs 3063: declaration is composed of the name of the constant, an equals sign, a keyword
1.18 cvs 3064: representing its type (<tt>Text</tt>, <tt>Symbol</tt>, <tt>Graphics</tt> or
3065: <tt>Picture</tt>) and the string representing its value. A semi-colon
3066: terminates each declaration.</p>
1.30 cvs 3067:
3068: <p>In the case of a character string, the keyword <tt>Text</tt> can be
3069: followed by the name of an alphabet (for example, <tt>Greek</tt> or
3070: <tt>Latin</tt>) in which the constant's text should be expressed. If the
3071: alphabet name is absent, the Latin alphabet is used. When the alphabet name
3072: is present, only the first letter of the alphabet name is interpreted. Thus,
3073: the words <tt>Greek</tt> and <tt>Grec</tt> designate the same alphabet. In
3074: current versions of Thot, only the Greek and Latin alphabets are
3075: available.</p>
1.18 cvs 3076: <pre> 'CONST' ConstSeq
1.30 cvs 3077: ConstSeq = Const < Const > .
1.1 cvs 3078: Const = ConstID '=' ConstType ConstValue ';' .
3079: ConstID = NAME .
3080: ConstType ='Text' [ Alphabet ] / 'Symbol' /
3081: 'Graphics' / 'Picture' .
3082: ConstValue = STRING .
1.18 cvs 3083: Alphabet = NAME .</pre>
1.30 cvs 3084:
3085: <p>For character strings in the Latin alphabet (ISO Latin-1 character set),
1.1 cvs 3086: characters having codes higher than 127 (decimal) are represented by their
1.18 cvs 3087: code in octal.</p>
1.30 cvs 3088:
3089: <p>In the case of a symbol or graphical element, the value only contains a
3090: single character, between apostrophes, which indicates the form of the element
3091: which must be drawn in the box whose content is the constant. The symbol or
1.1 cvs 3092: graphical element takes the dimensions of the box, which are determined by the
1.18 cvs 3093: <tt>Height</tt> and <tt>Width</tt> rules. See <a href="#sectb72">table of
3094: codes</a> for the symbols and graphical elements.</p>
1.30 cvs 3095:
1.18 cvs 3096: <blockquote class="example">
1.30 cvs 3097: <p><strong>Example:</strong></p>
3098:
3099: <p>The constants ``Summary:'' and fraction bar, which were described
3100: earlier, are declared:</p>
3101: <pre>CONST
1.1 cvs 3102: SummaryConst = Text 'Summary:';
1.18 cvs 3103: Bar = Graphics 'h';</pre>
3104: </blockquote>
3105: </div>
1.1 cvs 3106:
1.18 cvs 3107: <div class="subsection">
1.30 cvs 3108: <h3><a name="sectc426">Variables</a></h3>
1.1 cvs 3109:
1.30 cvs 3110: <p>Variables permit the definition of computed content for presentation boxes.
3111: A variable is associated with a presentation box by a <tt>Content</tt> rule;
3112: but before being used in a <tt>Content</tt> rule, a variable can be defined in
3113: the <tt>VAR</tt> section. It is also possible to define a variable at the
3114: time of its use in a <tt>Content</tt> rule, as can be done with a
3115: constant.</p>
3116:
3117: <p>A variable has a name and a value which is a character string resulting
3118: from the concatenation of the values of a sequence of functions. Each
3119: variable declaration is composed of the variable name followed by a colon and
3120: the sequence of functions which produces its value, separated by spaces. Each
1.18 cvs 3121: declaration is terminated by a semi-colon.</p>
3122: <pre> 'VAR' VarSeq
1.30 cvs 3123: VarSeq = Variable < Variable > .
1.1 cvs 3124: Variable = VarID ':' FunctionSeq ';' .
3125: VarID = NAME .
1.30 cvs 3126: FunctionSeq = Function < Function > .</pre>
3127:
3128: <p>Several functions are available. The first two return, in the form of a
1.18 cvs 3129: character string, the current date. <tt>DATE</tt> returns the date in
3130: English, while <tt>FDATE</tt> returns the date in french.</p>
1.30 cvs 3131:
3132: <p>Two other functions, <tt>DocName</tt> and <tt>DirName</tt>, return the
1.18 cvs 3133: document name and the directory where the document is stored.</p>
1.30 cvs 3134:
3135: <p>Function <tt>ElemName</tt> returns the type of the element which created
3136: the presentation box whose contents are the variable.</p>
3137:
3138: <p>Another function simply returns the value of a presentation constant. For
3139: any constant declared in the <tt>CONST</tt> section, it is sufficient to give
3140: the name of the constant. Otherwise, the type and value of the constant must
3141: be given, using the same form as in a <a href="#sectc425">constant
1.18 cvs 3142: declaration</a>. If the constant is not of type text, (types <tt>Symbol</tt>,
3143: <tt>Graphics</tt> or <tt>Picture</tt>), it must be alone in the variable
3144: definition; only constants of type <tt>Text</tt> can be mixed with other
3145: functions.</p>
1.30 cvs 3146:
3147: <p>It is also possible to obtain the value of an attribute, simply by
3148: mentioning the attribute's name. The value of this function is the value of
3149: the attribute for the element which created the presentation box whose
3150: contents are the variable. If the creating element does not have the
3151: indicated attribute, the value is an empty string. In the case of a numeric
3152: attribute, the attribute is translated into a decimal number in arabic
3153: numerals. If another form is desired, the <tt>VALUE</tt> function must be
3154: used.</p>
3155:
3156: <p>The last available function returns, as a character string, the value of a
1.1 cvs 3157: counter, an attribute or a page number. This value can be presented in
1.18 cvs 3158: different styles. The keyword <tt>VALUE</tt> is followed (between
1.1 cvs 3159: parentheses) by the name of the counter, the name of the attribute, or the
1.18 cvs 3160: keyword <tt>PageNumber</tt> and the desired style, the two parameters being
1.1 cvs 3161: separated by a comma. The style is a keyword which indicates whether the
1.18 cvs 3162: value should be presented in arabic numerals (<tt>Arabic</tt>), lower-case
3163: roman numerals (<tt>LRoman</tt>), or upper-case roman numerals
3164: (<tt>URoman</tt>), or by an upper-case letter (<tt>Uppercase</tt>) or
3165: lower-case letter (<tt>Lowercase</tt>).</p>
1.30 cvs 3166:
3167: <p>For a page counter, the keyword <tt>PageNumber</tt> can be followed,
3168: between parentheses, by the name of the view from which to obtain the page
3169: number. By default, the first view declared in the <tt>VIEWS</tt> section is
3170: used. The value obtained is the number of the page on which is found the
3171: element that is using the variable in a <tt>Content</tt> rule.</p>
3172:
3173: <p>For an ordinary counter, the name of the counter can be preceded by the
1.18 cvs 3174: keyword <tt>MaxRangeVal</tt> or <tt>MinRangeVal</tt>. These keywords mean
1.1 cvs 3175: that the value returned by the function is the maximum (minimum resp.) value
3176: taken by the counter in the whole document, not the value for the element
1.18 cvs 3177: concerned by the function.</p>
3178: <pre> Function = 'DATE' / 'FDATE' /
1.1 cvs 3179: 'DocName' / 'DirName' /
3180: 'ElemName' / 'AttributeName' /
3181: ConstID / ConstType ConstValue /
3182: AttrID /
3183: 'VALUE' '(' PageAttrCtr ','
3184: CounterStyle ')' .
1.6 cvs 3185: PageAttrCtr = 'PageNumber' [ '(' ViewID ')' ] /
1.1 cvs 3186: [ MinMax ] CounterID / AttrID .
3187: CounterStyle = 'Arabic' / 'LRoman' / 'URoman' /
3188: 'Uppercase' / 'Lowercase' .
1.18 cvs 3189: MinMax = 'MaxRangeVal' / 'MinRangeVal' .</pre>
1.30 cvs 3190:
1.18 cvs 3191: <blockquote class="example">
1.30 cvs 3192: <p><strong>Example:</strong></p>
3193:
3194: <p>To make today's date appear at the top of the first page of a report, a
3195: <a href="#sectc4232"><tt>CREATE</tt> rule</a> associated with the
3196: Report_Title element type generates a presentation box whose content
3197: (specified by the <tt>Content</tt> rule of that presentation box) is the
3198: variable:</p>
3199: <pre>VAR
1.18 cvs 3200: Todays_date : TEXT 'Version of ' DATE;</pre>
1.30 cvs 3201:
3202: <p>To produce, before each section title, the chapter number (in upper-case
3203: roman numerals) followed by the section number (in arabic numerals), two
3204: counters must be defined:</p>
3205: <pre>COUNTERS
1.1 cvs 3206: ChapterCtr : RANK OF Chapter;
1.18 cvs 3207: SectionCtr : RANK OF Section;</pre>
1.30 cvs 3208:
3209: <p>and the Section_Title element must create a presentation box whose
3210: content is the variable</p>
3211: <pre>VAR
1.1 cvs 3212: SectionNum : VALUE (ChapterCtr, URoman) TEXT '-'
1.18 cvs 3213: VALUE (SectionCtr, Arabic);</pre>
1.30 cvs 3214:
3215: <p>In order to make the page number on which each section begins appear in
3216: the table of contents view next to the section title, each Section_Title
3217: element must create a presentation box, visible only in the table of
3218: contents view, whose content is the variable:</p>
3219: <pre>VAR
1.1 cvs 3220: TitlePageNume :
1.18 cvs 3221: VALUE (PageNumber(Full_text), Arabic);</pre>
3222: </blockquote>
3223: </div>
1.1 cvs 3224:
1.18 cvs 3225: <div class="subsection">
1.30 cvs 3226: <h3><a name="sectc427">Default presentation rules</a></h3>
1.1 cvs 3227:
1.30 cvs 3228: <p>In order to avoid having to specify, for each element type defined in the
1.1 cvs 3229: structure schema, values for every one of the numerous presentation
1.34 ! cvs 3230: properties, the presentation schema allows the definition of a set of default
1.1 cvs 3231: presentation rules. These rules apply to all the boxes of the elements
3232: defined in the structure schema and to the presentation boxes and page layout
3233: boxes defined in the presentation schema. Only rules which differ from these
1.18 cvs 3234: default need to be specified in other sections of the presentation schema.</p>
1.30 cvs 3235:
3236: <p>For the primary view, the default rules can define every presentation
1.34 ! cvs 3237: property, but not the <a href="#presfunct">presentation functions</a> or the
1.18 cvs 3238: <a href="#sectc4223">linebreaking conditions</a> (the <tt>NoBreak1</tt>,
3239: <tt>NoBreak2</tt>, and <tt>Gather</tt> rules).</p>
1.30 cvs 3240:
3241: <p>In a presentation schema, the default presentation rules section is
3242: optional; in this case, the <tt>DEFAULT</tt> keyword is also absent and the
3243: following rules are considered to be the default rules:</p>
1.26 cvs 3244: <pre> Visibility: Enclosing =;
3245: VertRef: * . Left;
3246: HorizRef: Enclosed . HRef;
3247: Height: Enclosed . Height;
3248: Width: Enclosed . Width;
3249: VertPos: Top = Previous . Bottom;
3250: HorizPos: Left = Enclosing . Left;
3251: MarginTop: 0;
3252: MarginRight: 0;
3253: MarginBottom: 0;
3254: MarginLeft: 0;
3255: PaddingTop: 0;
3256: PaddingRight: 0;
3257: PaddingBottom: 0;
3258: PaddingLeft: 0;
3259: BorderTopWidth: 0;
3260: BorderRightWidth: 0;
3261: BorderBottomWidth: 0;
3262: BorderLeftWidth: 0;
3263: BorderTopColor: Foreground;
3264: BorderRightColor: Foreground;
3265: BorderBottomColor: Foreground;
3266: BorderLeftColor: Foreground;
3267: BorderTopStyle: None;
3268: BorderRightStyle: None;
3269: BorderBottomStyle: None;
3270: BorderLeftStyle: None;
3271: VertOverflow: No;
3272: HorizOverflow: No;
3273: Size: Enclosing =;
3274: Style: Enclosing =;
3275: Weight: Enclosing =;
3276: Font: Enclosing =;
3277: Underline: Enclosing =;
3278: Thickness: Enclosing =;
3279: Indent: Enclosing =;
3280: LineSpacing: Enclosing =;
3281: Adjust: Enclosing =;
3282: Justify: Enclosing =;
3283: Hyphenate: Enclosing =;
3284: PageBreak: Yes;
3285: LineBreak: Yes;
3286: InLine: Yes;
3287: Depth: 0;
3288: LineStyle: Enclosing =;
3289: LineWeight: Enclosing =;
3290: FillPattern: Enclosing =;
3291: Background: Enclosing =;
3292: Foreground: Enclosing =;</pre>
1.30 cvs 3293:
3294: <p>If other values are desired for the default rules, they must be defined
1.1 cvs 3295: explicitly in the default rules section. In fact, it is only necessary to
3296: define those default rules which differ from the ones above, since the rules
1.18 cvs 3297: above will be used whenever a rule is not explicitly named.</p>
1.30 cvs 3298:
3299: <p>Default rules for views other than the primary view can also be specified.
1.1 cvs 3300: Otherwise, the default rules for the primary views are applied to the other
1.18 cvs 3301: views.</p>
1.30 cvs 3302:
3303: <p>Default rules are expressed in the same way as <a
3304: href="#sectc4215">explicit rules for document elements</a>.</p>
1.18 cvs 3305: </div>
1.1 cvs 3306:
1.18 cvs 3307: <div class="subsection">
1.30 cvs 3308: <h3><a name="sectc428">Presentation and page layout boxes</a></h3>
1.1 cvs 3309:
1.30 cvs 3310: <p>The presentation process uses elements which are not part of the logical
1.1 cvs 3311: structure of the document, such as pages (which are the page layout boxes) or
3312: alternatively, rules, numbers, or words introducing certain parts of the
3313: document, such as ``Summary'', ``Appendices'', ``Bibliography'', etc. (which
1.18 cvs 3314: are presentation boxes).</p>
1.30 cvs 3315:
3316: <p>After the word <tt>BOXES</tt>, each presentation or page layout box is
3317: defined by its name and a sequence of presentation rules which indicate how
3318: they must be displayed. These rules are the same as those which define the
3319: boxes associated with element of the logical structure of the document, with a
1.18 cvs 3320: single exception, the <a href="#sectc4231"><tt>Content</tt> rule</a> which is
1.1 cvs 3321: used only to specify the content of presentation boxes. The content of boxes
3322: associated with elements of the document structure is defined in each document
3323: or object and thus is not specified in the presentation schema, which applies
1.18 cvs 3324: to all documents or objects of a class.</p>
1.30 cvs 3325:
3326: <p>Among the rules which define a presentation box, certain ones can refer to
1.1 cvs 3327: another presentation box (for example, in their positional rules). If the
3328: designated box is defined after the box which designates it, a
1.18 cvs 3329: <tt>FORWARD</tt> instruction followed by the name of the designated box must
3330: appear before the designation.</p>
3331: <pre> 'BOXES' BoxSeq
1.30 cvs 3332: BoxSeq = Box < Box > .
1.1 cvs 3333: Box ='FORWARD' BoxID ';' /
3334: BoxID ':' ViewRuleSeq .
1.18 cvs 3335: BoxID = NAME .</pre>
3336: </div>
1.1 cvs 3337:
1.18 cvs 3338: <div class="subsection">
1.30 cvs 3339: <h3><a name="sectc429">Presentation of structured elements</a></h3>
1.1 cvs 3340:
1.30 cvs 3341: <p>After the words <tt>RULES</tt>, the presentation schema gives the
3342: presentation rules that apply to the elements whose types are defined in the
3343: structure schema. Only those rules which differ from the <a
1.18 cvs 3344: href="#sectc427">default</a> must be specified in the <tt>RULES</tt>
3345: section.</p>
1.30 cvs 3346:
3347: <p>The rule definitions for each element type are composed of the name of the
1.1 cvs 3348: element type (as specified in the structure schema) followed by a colon and
1.18 cvs 3349: the set of rules specific to that type.</p>
1.30 cvs 3350:
3351: <p>The type name can be preceded by a star in the special case where the
1.18 cvs 3352: structure schema defines an <a href="#sectd3284">inclusion</a> without
1.1 cvs 3353: expansion (or with partial expansion) of a type with the same name as an
1.18 cvs 3354: element of defined in the structure schema.</p>
1.30 cvs 3355:
3356: <p>In the case where the element is a <a href="#sectd3285">mark pair</a>, but
1.18 cvs 3357: only in this case, the type name can be preceded by the keywords
3358: <tt>First</tt> or <tt>Second</tt>. These keywords indicate whether the rules
3359: that follow apply to the first or second mark of the pair.</p>
3360: <pre> 'RULES' PresentSeq
1.30 cvs 3361: PresentSeq = Present < Present > .
1.6 cvs 3362: Present = [ '*' ] [ FirstSec ] ElemID ':'
3363: ViewRuleSeq .
1.18 cvs 3364: FirstSec = 'First' / 'Second' .</pre>
1.30 cvs 3365:
3366: <p>A presentation schema can define presentation rules for base elements,
3367: which are defined implicitly in the structure schemas. In the English version
3368: of the presentation schema compiler, the base type names are the same as in
3369: the S language, but they are terminated by the <tt>_UNIT</tt> suffix:
1.18 cvs 3370: <tt>TEXT_UNIT</tt>, <tt>PICTURE_UNIT</tt>, <tt>SYMBOL_UNIT</tt>,
3371: <tt>GRAPHICS_UNIT</tt>. The base type names are written in upper-case
3372: letters.</p>
3373: </div>
3374:
3375: <div class="subsection">
1.30 cvs 3376: <h3><a name="sectc4210">Logical attribute presentation</a></h3>
1.18 cvs 3377:
1.30 cvs 3378: <p>After the keyword <tt>ATTRIBUTES</tt>, all attributes which are to have
3379: some effect on the presentation of the element to which they are attached must
3380: be mentioned, along with the corresponding presentation rules. This is true
3381: for both global attributes (which can be attached to all element types) and
3382: local attributes (which can only be attached to certain element types).</p>
3383:
3384: <p>Also mentioned in this section are attributes which imply an effect on
1.1 cvs 3385: elements in the subtree of the element to which they are attached. The
3386: presentation of these descendants can be modified as a function of the value
3387: of the attribute which they inherit, just as if it was attached to them
1.18 cvs 3388: directly.</p>
1.30 cvs 3389:
3390: <p>The specification for each attribute includes the attribute's name,
3391: followed by an optional value specification and, after a colon, a set of
3392: rules. The set of rules must contain at least one rule.</p>
3393:
3394: <p>When there is no value specification, the rules are applied to all elements
1.1 cvs 3395: which carry the attribute, no matter what their value. When the rules must
3396: only apply when the attribute has certain values, these values must be
1.18 cvs 3397: specified. Thus, the same attribute can appear in the <tt>ATTRIBUTES</tt>
1.1 cvs 3398: section several times, with each appearance having a different value
3399: specification. However, reference attributes never have a value specification
1.18 cvs 3400: and, as a result, can only appear once in the <tt>ATTRIBUTES</tt> section.</p>
1.30 cvs 3401:
3402: <p>To specify that the presentation rules apply to some of the descendants of
3403: the element having the attribute, the name of the affected element type is
3404: given, between parentheses, after the attribute name. This way, the
3405: presentation rules for the attribute will be applied to the element having the
3406: attribute, if it is of the given type, and to all of its descendants of the
3407: given type. In the case where this type is a <a href="#sectd3285">mark
3408: pair</a>, but only in this case, the type name can be preceded by the keywords
3409: <tt>First</tt> or <tt>Second</tt>. These keywords indicate whether the rules
3410: that follow apply to the first or second mark of the pair. If the rule must
3411: apply to several different element types, the specification must be repeated
3412: for each element type.</p>
3413:
3414: <p>The specification of values for which the presentation rules will be
3415: applied varies according to the type of the attribute:</p>
1.18 cvs 3416: <dl>
1.30 cvs 3417: <dt>numeric attribute</dt>
3418: <dd>If the rules are to apply for one value of the attribute, then the
3419: attribute name is followed by an equals sign and this value. If the
3420: rules are to apply for all values less than (or greater than) a
3421: threshold value, non-inclusive, the attribute name followed by a '<'
3422: sign (or a '>' sign, respectively) and the threshold value. If the
3423: rules must apply to a range of values, the attribute name is followed by
3424: the word '<tt>IN</tt>' and the two bounds of the range, enclosed in
3425: brackets and separated by two periods ('<tt>..</tt>'). In the case of
3426: ranges, the values of the bounds are included in the range.
3427: <p>The threshold value in the comparisons can be the value of an
3428: attribute attached to an ancestor element. In this case, the attribute
3429: name is given instead of a constant value.</p>
3430: <p>It is also possible to write rules which apply only when a comparison
3431: between two different attributes of the element's ancestors is true. In
3432: this case, the first attribute name is followed by a comparison keyword
3433: and the name of the second attribute. The comparison keywords are
3434: <tt>EQUAL</tt> (simple equality), <tt>LESS</tt> (non-inclusive less
3435: than), and <tt>GREATER</tt> (non-inclusive greater than).</p>
3436: </dd>
3437: <dt>text attribute</dt>
3438: <dd>If the rules are to apply for one value of the attribute, then the
3439: attribute name is followed by an equals sign and this value.</dd>
3440: <dt>reference attribute</dt>
3441: <dd>There is never a value specification; the rules apply no matter what
3442: element is designated by the attribute.</dd>
3443: <dt>enumerated attribute</dt>
3444: <dd>If the rules are to apply for one value of the attribute, then the
3445: attribute name is followed by an equals sign and this value.</dd>
1.18 cvs 3446: </dl>
1.30 cvs 3447:
3448: <p>The order in which the rules associated with a numeric attribute are
3449: defined is important. When multiple sets of rules can be applied, the first
3450: set declared is the one used.</p>
3451:
3452: <p>Rules for attributes have priority over both default rules and rules
1.1 cvs 3453: associated with element types. The attribute rules apply to the element to
3454: which the attribute is attached. It is the rules which apply to the
3455: surrounding elements (and especially to the descendants) which determine the
3456: effect of the attribute rules on the environment ( and especially on the
1.18 cvs 3457: terminal elements of the structure).</p>
3458: <pre> 'ATTRIBUTES' PresAttrSeq
1.30 cvs 3459: PresAttrSeq = PresAttr < PresAttr > .
1.1 cvs 3460: PresAttr = AttrID [ '(' [ FirstSec ] ElemID ')' ]
3461: [ AttrRelation ] ':' ViewRuleSeq .
3462: AttrID = NAME .
3463: AttrRelation ='=' AttrVal /
1.30 cvs 3464: '>' [ '-' ] MinValue /
1.1 cvs 3465: '<' [ '-' ] MaxValue /
3466: 'IN' '[' [ '-' ] LowerBound '..'
3467: [ '-' ] UpperBound ']' /
3468: 'GREATER' AttrID /
3469: 'EQUAL' AttrID /
3470: 'LESS' AttrID .
3471: AttrVal = [ '-' ] EqualNum / EqualText /
3472: AttrValue .
3473: MinValue = NUMBER .
3474: MaxValue = NUMBER .
3475: LowerBound = NUMBER .
3476: UpperBound = NUMBER.
3477: EqualNum = NUMBER .
3478: EqualText = STRING .
1.18 cvs 3479: AttrValue = NAME .</pre>
1.30 cvs 3480:
3481: <p>In presentation rules associated with a numeric attribute (and only in such
1.1 cvs 3482: rules), the attribute name can be used in place of a numeric value. In this
3483: case, the value of the attribute is used in the application of the rule. Thus,
3484: the attribute can represent a relation between the size of two boxes, the
3485: height and width of a box, the height of an area where page breaks are
3486: prohibited, the distance between two boxes, the position of the reference axis
3487: of a box, the interline spacing, the indentation of the first line, the
1.18 cvs 3488: visibility, the depth (z-order), or the character set.</p>
1.30 cvs 3489:
3490: <p>The presentation rules associated with reference attributes, it is possible
3491: to use the element designated by the attribute as a reference box in a
3492: positional or extent rule. This element is represented in the <a
1.18 cvs 3493: href="#sectc4218">position</a> or <a href="#sectc4219">extent</a> rule by the
3494: keyword <tt>Referred</tt>.</p>
1.30 cvs 3495:
1.18 cvs 3496: <blockquote class="example">
1.30 cvs 3497: <p><strong>Example:</strong></p>
3498:
3499: <p>In all structure schemas, there is a global Language attribute defined as
3500: follows:</p>
3501: <pre>ATTR
1.18 cvs 3502: Language = TEXT;</pre>
1.30 cvs 3503:
3504: <p>The following rules would make French text be displayed in roman
3505: characters and English text be displayed in italics:</p>
3506: <pre>ATTRIBUTES
1.1 cvs 3507: Language = 'French' :
1.6 cvs 3508: Style : Roman;
1.1 cvs 3509: Language = 'English' :
1.18 cvs 3510: Style : Italics;</pre>
1.30 cvs 3511:
3512: <p>Using these rules, when the user puts the Language attribute with the
3513: value 'English' on the summary of a document, every character string
3514: (terminal elements) contained in the summary are displayed in italics. See
3515: the <a href="#sectd42252"><tt>Style</tt> rule</a>.</p>
1.18 cvs 3516: </blockquote>
1.30 cvs 3517:
1.18 cvs 3518: <blockquote class="example">
1.30 cvs 3519: <p><strong>Example:</strong></p>
3520:
3521: <p>A numeric attribute representing the importance of the part of the
3522: document to which it is attached can be defined:</p>
3523: <pre>ATTR
1.18 cvs 3524: Importance = INTEGER;</pre>
1.30 cvs 3525:
3526: <p>In the presentation schema, the importance of an element is reflected in
3527: the choice of character size, using the following rules.</p>
3528: <pre>ATTRIBUTES
1.1 cvs 3529: Importance < 2 :
3530: Size : 1;
3531: Importance IN [2..4] :
3532: Size : Importance;
3533: Importance = 10 :
3534: Size : 5;
1.30 cvs 3535: Importance > 4 :
1.18 cvs 3536: Size : 4;</pre>
1.30 cvs 3537:
3538: <p>Thus, the character size corresponds to the value of the Importance
3539: attribute; its value is</p>
3540: <ul>
3541: <li>the value of the Importance attribute when the value is between 2 and
3542: 4 (inclusive),</li>
3543: <li>1, when the value of the Importance attribute is less than 2,</li>
3544: <li>4, when the value of the Importance attribute is greater than 4,</li>
3545: <li>5, when the value of the Importance attribute is 10.</li>
3546: </ul>
3547:
3548: <p>The last case (value 5) must be defined before the case which handles all
3549: Importance values greater than 4, because the two rules are not disjoint and
3550: the first one defined will have priority. Otherwise, when the Importance
3551: attribute has value 10, the font size will be 4.</p>
1.18 cvs 3552: </blockquote>
1.30 cvs 3553:
1.18 cvs 3554: <blockquote class="example">
1.30 cvs 3555: <p><strong>Example:</strong></p>
3556:
3557: <p>Suppose the structure defines a list element which can have an attribute
3558: defining the type of list (numbered or not):</p>
3559: <pre>STRUCT
1.1 cvs 3560: list (ATTR list_type = enumeration, dash)
1.18 cvs 3561: = LIST OF (list_item = TEXT);</pre>
1.30 cvs 3562:
3563: <p>Then, the presentation schema could use the attribute placed on the list
3564: element to put either a dash or a number before the each element of the
3565: list:</p>
3566: <pre>ATTRIBUTES
1.1 cvs 3567: list_type (list_item) = enumeration :
3568: CreateBefore (NumberBox);
3569: list_type (list_item) = dash :
1.18 cvs 3570: CreateBefore (DashBox);</pre>
3571: </blockquote>
1.30 cvs 3572:
1.18 cvs 3573: <blockquote class="example">
1.30 cvs 3574: <p><strong>Example:</strong></p>
3575:
3576: <p>Suppose that two attributes are defined in the structure schema. The
3577: first is a numeric global attribute called ``version''. The other is a
3578: local attribute defined on the root of the document called
3579: ``Document_version'':</p>
3580: <pre>STRUCTURE Document
1.1 cvs 3581: ATTR
3582: version = INTEGER;
3583: STRUCT
3584: Document (ATTR Document_version = INTEGER) =
3585: BEGIN
3586: SomeElement ;
3587: ...
3588: SomeOtherElement ;
3589: END ;
1.18 cvs 3590: ...</pre>
1.30 cvs 3591:
3592: <p>These attributes can be used in the presentation schema to place change
3593: bars in the margin next to elements whose version attribute has a value
3594: equal to the Document_version attribute of the root and to place a star in
3595: margin of elements whose version attribute is less than the value of the
3596: root's Document_version attribute:</p>
3597: <pre>ATTRIBUTES
1.1 cvs 3598: version EQUAL Document_version :
3599: CreateBefore (ChangeBarBox) ;
3600: version LESS Document_version :
1.18 cvs 3601: CreateBefore (StarBox) ;</pre>
3602: </blockquote>
3603: </div>
1.1 cvs 3604:
1.18 cvs 3605: <div class="subsection">
1.30 cvs 3606: <h3><a name="sectc4212">Value transmission rules</a></h3>
1.1 cvs 3607:
1.30 cvs 3608: <p>The last section of a presentation schema, which is optional, serves to
1.1 cvs 3609: defines the way in which a document transmits certain values to its
1.18 cvs 3610: sub-documents. A sub-document is an document <a
3611: href="#inclusion">included</a> without expansion or with partial expansion.
1.1 cvs 3612: The primary document can transmit to its sub-documents the values of certain
3613: counters or the textual content of certain of its elements, as a function of
1.18 cvs 3614: their type.</p>
1.30 cvs 3615:
3616: <p>The sub-documents receive these values in attributes which must be defined
3617: in their structure schema as local attributes of the root element. The types
3618: of these attributes must correspond to the type of the value which they
3619: receive: numeric attributes for receiving the value of a counter, textual
3620: attributes for receiving the content of an element.</p>
3621:
3622: <p>In the structure schema of the primary document, there appears at the end,
1.18 cvs 3623: after the <tt>TRANSMIT</tt> keyword, a sequence of transmission rules. Each
1.1 cvs 3624: rule begins with the name of the counter to transmit or of the element type
3625: whose textual content will be transmitted. This name is followed by the
1.18 cvs 3626: keyword <tt>To</tt> and the name of the attribute of the sub-document to which
1.1 cvs 3627: the value is transmitted. The sub-document class is indicated between
3628: parentheses after the name of the attribute. The transmission rule ends with
1.18 cvs 3629: a semicolon.</p>
1.30 cvs 3630: <pre> TransmitSeq = Transmit < Transmit > .
1.1 cvs 3631: Transmit = TypeOrCounter 'To' ExternAttr
3632: '(' ElemID ')' ';' .
3633: TypeOrCounter = CounterID / ElemID .
1.18 cvs 3634: ExternAttr = NAME .</pre>
1.30 cvs 3635:
1.18 cvs 3636: <blockquote class="example">
1.30 cvs 3637: <p><strong>Example:</strong></p>
3638:
3639: <p>Consider a Book document class which includes instances of the Chapter
3640: document class. These classes might have the following schemas:</p>
3641: <pre>STRUCTURE Book
1.1 cvs 3642: STRUCT
3643: Book = BEGIN
3644: Title = Text;
3645: Body = LIST OF (Chapter INCLUDED);
3646: END;
3647: ...
3648:
3649: STRUCTURE Chapter
3650: STRUCT
3651: Chapter (ATTR FirstPageNum = Integer;
3652: ChapterNum = Integer;
3653: CurrentTitle = Text) =
1.6 cvs 3654: BEGIN
3655: ChapterTitle = Text;
3656: ...
3657: END;
1.18 cvs 3658: ...</pre>
1.30 cvs 3659:
3660: <p>Then the presentation schema for books could define chapter and page
3661: counters. The following transmission rules in the book presentation schema
3662: would transmit values for the three attributes defined at the root of each
3663: chapter sub-document.</p>
3664: <pre>PRESENTATION Book;
1.1 cvs 3665: VIEWS
3666: Full_text;
3667: COUNTERS
3668: ChapterCtr: Rank of Chapter;
3669: PageCtr: Rank of Page(Full_text);
3670: ...
3671: TRANSMIT
3672: PageCtr TO FirstPageNum(Chapter);
3673: ChapterCtr TO ChapterNum(Chapter);
3674: Title TO CurrentTitle(Chapter);
1.18 cvs 3675: END</pre>
1.30 cvs 3676:
3677: <p>Thus, each chapter included in a book can number its pages as a function
3678: of the number of pages preceding it in the book, can make the chapter's
3679: number appear before the number of each of its sections, or can place the
3680: title of the book at the top of each page.</p>
1.18 cvs 3681: </blockquote>
3682: </div>
1.1 cvs 3683:
1.18 cvs 3684: <div class="subsection">
1.30 cvs 3685: <h3><a name="sectc4213">Presentation rules</a></h3>
1.1 cvs 3686:
1.30 cvs 3687: <p>Whether defining the appearance of a presentation or page layout box, an
1.1 cvs 3688: element type, or an attribute value, the set of presentation rules that apply
1.18 cvs 3689: is always defined in the same way.</p>
1.30 cvs 3690:
3691: <p>Normally, a set of presentation rules is placed between the keywords
1.18 cvs 3692: <tt>BEGIN</tt> and <tt>END</tt>, the keyword <tt>END</tt> being followed by a
1.1 cvs 3693: semicolon. The first section of this block defines the rules that apply to
1.18 cvs 3694: the primary view, if the <a href="#sectc427">default rules</a> are not
1.1 cvs 3695: completely suitable. Next comes the rules which apply to specific other
3696: views, with a rule sequence for each view for which the default rules are not
3697: satisfactory. If the default rules are suitable for the non-primary views,
3698: there will not be any specific rules for these views. If there is only one
1.18 cvs 3699: rule which applies to all views then the keywords <tt>BEGIN</tt> and
3700: <tt>END</tt> need not appear.</p>
1.30 cvs 3701:
3702: <p>For each view, it is only necessary to specify those rules which differ
3703: from the default rules for the view, so that for certain views (or even all
3704: views), there may be no specific rules.</p>
3705:
3706: <p>The specific rules for a non-primary view are introduced by the <a
1.18 cvs 3707: name="inkeyword"><tt>IN</tt> keyword</a>, followed by the view name. The
3708: rules for that view follow, delimited by the keywords <tt>BEGIN</tt> and
3709: <tt>END</tt>, or without these two keywords when there is only one rule.</p>
1.30 cvs 3710:
3711: <p><strong>Note:</strong> the view name which follows the <tt>IN</tt> keyword
1.1 cvs 3712: must not be the name of the primary view, since the rules for that view are
1.18 cvs 3713: found before the rules for the other views.</p>
1.30 cvs 3714:
3715: <p>Within each block concerning a view, other blocks can appear, delimited by
3716: the same keywords <tt>BEGIN</tt> and <tt>END</tt>. Each of these blocks
3717: gathers the presentation rules that apply, for a given view, only when a given
1.1 cvs 3718: condition is satisfied. Each block is preceded by a condition introduced by
1.18 cvs 3719: the <tt>IF</tt> keyword. If such a conditional block contains only one rule,
3720: the keywords <tt>BEGIN</tt> and <tt>END</tt> can be omitted.</p>
1.30 cvs 3721:
3722: <p>Although the syntax allows any presentation rule to appear in a conditional
1.18 cvs 3723: block, only <a href="#sectc4232">creation rules</a> are allowed after any
3724: condition; other rules are allowed only after conditions <tt>Within</tt> and
1.1 cvs 3725: ElemID. In addition, the following rules cannot be conditional:
1.18 cvs 3726: <tt>PageBreak, LineBreak, Inline, Gather</tt>.</p>
1.30 cvs 3727:
3728: <p>For a given view, the rules that apply without any condition must appear
1.1 cvs 3729: before the first conditional block. If some rules apply only when none of the
3730: specified condition holds, they are grouped in a block preceded by the keyword
1.18 cvs 3731: <tt>Otherwise</tt>, and that block must appear after the last conditionnal
3732: block concerning the same view.</p>
1.30 cvs 3733: <pre> ViewRuleSeq = 'BEGIN' < RulesAndCond > < ViewRules >
1.1 cvs 3734: 'END' ';' /
3735: ViewRules / CondRules / Rule .
3736: RulesAndCond = CondRules / Rule .
3737: ViewRules = 'IN' ViewID CondRuleSeq .
1.30 cvs 3738: CondRuleSeq = 'BEGIN' < RulesAndCond > 'END' ';' /
1.1 cvs 3739: CondRules / Rule .
1.30 cvs 3740: CondRules = CondRule < CondRule >
1.1 cvs 3741: [ 'Otherwise' RuleSeq ] .
3742: CondRule = 'IF' ConditionSeq RuleSeq .
1.30 cvs 3743: RulesSeq = 'BEGIN' Rule < Rule > 'END' ';' /
1.18 cvs 3744: Rule .</pre>
1.30 cvs 3745:
1.18 cvs 3746: <blockquote class="example">
1.30 cvs 3747: <p><strong>Example:</strong></p>
3748:
3749: <p>The following rules for a report's title make the title visible in the
3750: primary view and invisible in the table of contents and in the formula views
3751: (see the <a href="#sectc4224"><tt>Visibility</tt> rule</a>).</p>
3752: <pre>Title : BEGIN
1.1 cvs 3753: Visibility : 1;
3754: ... {Other rules for the primary view}
3755: IN Table_of_contents
3756: Visibility : 0;
3757: IN Formulas
3758: Visibility : 0;
1.18 cvs 3759: END;</pre>
3760: </blockquote>
3761: </div>
1.1 cvs 3762:
1.18 cvs 3763: <div class="subsection">
1.30 cvs 3764: <h3><a name="sectc4214">Conditions applying to presentation rules</a></h3>
1.1 cvs 3765:
1.30 cvs 3766: <p>Many conditions can be applied to presentation rules. Conditions allow
1.1 cvs 3767: certain presentation rules to apply only in certain cases. These conditions
3768: can be based on the structural position of the element. They can be based on
3769: whether the element has references, and what type of references, whether the
1.33 cvs 3770: element has attributes, whether the element is empty or not, whether the
3771: element is the root of its document or not. They can also be based on the
3772: value of a counter.</p>
1.30 cvs 3773:
3774: <p>It is possible to specify several conditions which must all be true for the
1.18 cvs 3775: rules to apply.</p>
1.30 cvs 3776:
3777: <p>A set of conditions is specified by the <tt>IF</tt> keyword. This keyword
3778: is followed by the sequence of conditions, separated by the <tt>AND</tt>
3779: keyword. Each condition is specified by a keyword which defines the condition
3780: type. In some cases, the keyword is followed by other data, which specify the
3781: condition more precisely.</p>
3782:
3783: <p>An elementary condition can be negative; it is then preceded by the
1.18 cvs 3784: <tt>NOT</tt> keyword.</p>
1.30 cvs 3785:
3786: <p>When the presentation rule(s) controlled by the condition apply to a
3787: reference element or a reference attribute, an elementary condition can also
3788: apply to element referred by this reference. The <tt>Target</tt> keyword is
3789: used for that purpose. It must appear before the keyword defining the
3790: condition type.</p>
1.18 cvs 3791: <pre> CondRule ='IF' ConditionSeq RuleSeq .
1.30 cvs 3792: ConditionSeq = Condition < 'AND' Condition > .
1.1 cvs 3793: Condition = [ 'NOT' ] [ 'Target' ] ConditionElem .
3794: ConditionElem ='First' / 'Last' /
3795: [ 'Immediately' ] 'Within' [ NumParent ]
3796: ElemID [ ExtStruct ] /
3797: ElemID /
3798: 'Referred' / 'FirstRef' / 'LastRef' /
3799: 'ExternalRef' / 'InternalRef' / 'CopyRef' /
3800: 'AnyAttributes' / 'FirstAttr' / 'LastAttr' /
3801: 'UserPage' / 'StartPage' / 'ComputedPage' /
1.33 cvs 3802: 'Empty' / 'Root' /
1.1 cvs 3803: '(' [ MinMax ] CounterName CounterCond ')' /
3804: CondPage '(' CounterID ')' .
3805: NumParent = [ GreaterLess ] NParent .
1.30 cvs 3806: GreaterLess ='>' / '<' .
1.1 cvs 3807: NParent = NUMBER.
1.6 cvs 3808: ExtStruct ='(' ElemID ')' .
1.30 cvs 3809: CounterCond ='<' MaxCtrVal / '>' MinCtrVal /
1.1 cvs 3810: '=' EqCtrVal /
3811: 'IN' '[' ['-'] MinCtrBound '.' '.'
3812: ['-'] MaxCtrBound ']' .
3813: PageCond ='Even' / 'Odd' / 'One' .
3814: MaxCtrVal = NUMBER .
3815: MinCtrVal = NUMBER .
3816: EqCtrVal = NUMBER .
3817: MaxCtrBound = NUMBER .
1.18 cvs 3818: MinCtrBound = NUMBER .</pre>
1.1 cvs 3819:
1.18 cvs 3820: <div class="subsubsection">
3821: <h4><a name="sectd42141">Conditions based on the logical position of the
3822: element</a></h4>
1.30 cvs 3823:
3824: <p>The condition can be on the position of the element in the document's
3825: logical structure tree. It is possible to test whether the element is the
3826: first (<tt>First</tt>) or last (<tt>Last</tt>) among its siblings or if it is
3827: not the first (<tt>NOT First</tt>) or not the last (<tt>NOT Last</tt>). These
1.18 cvs 3828: conditions can be associated only with <a href="#sectc4232">creation
3829: rules</a>.</p>
1.30 cvs 3830:
1.33 cvs 3831: <p>It is possible to test if the element is the root of its document (keyword
3832: <code>Root</code>).</p>
3833:
1.30 cvs 3834: <p>It is also possible to test if the element is contained in an element of a
1.18 cvs 3835: given type (<tt>Within</tt>) or if it is not (<tt>NOT Within</tt>). The type
3836: is indicated after the keyword <tt>Within</tt>. If that element type is
1.1 cvs 3837: defined in a structure schema which is not the one which corresponds to the
3838: presentation schema, the type name of this element must be followed, between
1.18 cvs 3839: parentheses, by the name of the structure schema which defines it.</p>
1.30 cvs 3840:
3841: <p>If the keyword <tt>Within</tt> is preceded by <tt>Immediately</tt>, the
1.18 cvs 3842: condition is satisfied only if the <em>parent</em> element has the type
3843: indicated. If the word <tt>Immediately</tt> is missing, the condition is
3844: satisfied if any <em>ancestor</em> has the type indicated.</p>
1.30 cvs 3845:
3846: <p>An integer <i>n</i> can appear between the keyword <tt>Within</tt> and the
1.1 cvs 3847: type. It specifies the number of ancestors of the indicated type that must be
3848: present for the condition to be satisfied. If the keyword
1.18 cvs 3849: <tt>Immediately</tt> is also present, the <i>n</i> immediate ancestors of the
3850: element must have the indicated type. The integer <i>n</i> must be positive
1.30 cvs 3851: or zero. It can be preceded by <tt><</tt> or <tt>></tt> to indicate a
1.1 cvs 3852: maximum or minimum number of ancestors. If these symbols are missing, the
1.18 cvs 3853: condition is satisfied only if it exists exactly <i>n</i> ancestors. When
1.30 cvs 3854: this number is missing, it is equivalent to > 0.</p>
3855:
3856: <p>If the condition applies to presentation rules associated with an
3857: attribute, in the <tt>ATTRIBUTES</tt> section of the presentation schema, the
3858: condition can be simply an element name. Presentation rules are then executed
3859: only if the attribute is attached to an element of that type. The keyword
3860: <tt>NOT</tt> before the element name indicates that the presentation rules
3861: must be executed only if the element is not of the type indicated.</p>
1.18 cvs 3862: </div>
1.1 cvs 3863:
1.18 cvs 3864: <div class="subsubsection">
1.30 cvs 3865: <h4><a name="sectd42142">Conditions on references</a></h4>
3866:
3867: <p>References may be taken into account in conditions, which can be based on
3868: the fact that the element, or one of its ancestors, is designated by a at
3869: least one reference (<tt>Referred</tt>) or by none (<tt>NOT
3870: Referred</tt>).</p>
3871:
3872: <p>If the element or attribute to which the condition is attached is a
3873: reference, the condition can be based on the fact that it acts as the first
3874: reference to the designated element (<tt>FirstRef</tt>), or as the last
3875: (<tt>LastRef</tt>), or as a reference to an element located in another
3876: document (<tt>ExternalRef</tt>) or in the same document
3877: (<tt>InternalRef</tt>).</p>
1.1 cvs 3878:
1.30 cvs 3879: <p>The condition can also be based on the fact that the element is an <a
1.18 cvs 3880: href="#inclusion">inclusion</a>. This is noted (<tt>CopyRef</tt>).</p>
1.30 cvs 3881:
3882: <p>Like all conditions, conditions on references can be inverted by the
1.18 cvs 3883: <tt>NOT</tt> keyword. These conditions can be associated only with <a
3884: href="#sectc4232">creation rules</a>.</p>
3885: </div>
1.1 cvs 3886:
1.18 cvs 3887: <div class="subsubsection">
1.30 cvs 3888: <h4><a name="sectd42143">Conditions on logical attributes</a></h4>
3889:
3890: <p>The condition can be based on the presence or absence of attributes
3891: associated with the element, no matter what the attributes or their values.
3892: The <tt>AnyAttributes</tt> keyword expresses this condition.</p>
1.1 cvs 3893:
1.30 cvs 3894: <p>If the condition appears in the presentation rules of an attribute, the
1.18 cvs 3895: <tt>FirstAttr</tt> and <tt>LastAttr</tt> keywords can be used to indicate that
1.1 cvs 3896: the rules must only be applied if this attribute is the first attribute for
3897: the element or if it is the last (respectively). These conditions can also be
1.18 cvs 3898: inverted by the <tt>NOT</tt> keyword. These conditions can be associated only
3899: with <a href="#sectc4232">creation rules</a>.</p>
1.30 cvs 3900:
3901: <p>It is also possible to apply certain presentation rules only when the
3902: element being processed or one of its ancestors has a certain attribute,
3903: perhaps with a certain value. This can be done in the <a
1.18 cvs 3904: href="#sectc4210"><tt>ATTRIBUTES</tt> section</a>.</p>
3905: </div>
1.1 cvs 3906:
1.18 cvs 3907: <div class="subsubsection">
1.30 cvs 3908: <h4><a name="sectd42144">Conditions on page breaks</a></h4>
1.1 cvs 3909:
1.30 cvs 3910: <p>The page break base type (and only this type) can use the following
1.18 cvs 3911: conditions: <tt>ComputedPage</tt>, <tt>StartPage</tt>, and <tt>UserPage</tt>.
3912: The <tt>ComputedPage</tt> condition indicates that the presentation rule(s)
1.1 cvs 3913: should apply if the page break was created automatically by Thot; the
1.18 cvs 3914: <tt>StartPage</tt> condition is true if the page break is generated before the
3915: element by the <tt>Page</tt> rule; and the <tt>UserPage</tt> condition applies
3916: if the page break was inserted by the user.</p>
1.30 cvs 3917:
3918: <p>These conditions can be associated only with <a href="#sectc4232">creation
1.18 cvs 3919: rules</a>.</p>
3920: </div>
1.1 cvs 3921:
1.18 cvs 3922: <div class="subsubsection">
1.30 cvs 3923: <h4><a name="sectd42145">Conditions on the element's content</a></h4>
1.1 cvs 3924:
1.30 cvs 3925: <p>The condition can be based on whether or not the element is empty. An
3926: element which has no children or whose leaves are all empty is considered to
3927: be empty itself. This condition is expressed by the <tt>Empty</tt> keyword,
3928: optionally preceded by the <tt>NOT</tt> keyword. This condition can be
3929: associated only with <a href="#sectc4232">creation rules</a>.</p>
1.18 cvs 3930: </div>
1.1 cvs 3931:
1.18 cvs 3932: <div class="subsubsection">
1.30 cvs 3933: <h4><a name="sectd42146">Conditions on counters</a></h4>
1.1 cvs 3934:
1.30 cvs 3935: <p>Presentation rules can apply when the counter's value is one, is even or
3936: odd, is equal, greater than or less than a given value or falls in a range of
1.1 cvs 3937: values. This is particularly useful for creating header and footer boxes.
1.18 cvs 3938: These conditions can be associated only with <a href="#sectc4232">creation
3939: rules</a>.</p>
1.30 cvs 3940:
3941: <p>To compare the value of a counter to a given value, a comparison is given
1.1 cvs 3942: between parentheses. The comparison is composed of the counter name followed
3943: by an equals, greater than, or less than sign and the value to which the
3944: counter will be compared. A test for whether or not a counter's value falls
3945: in a range also appears within parentheses. In this case, the counter name is
1.18 cvs 3946: followed by the <tt>IN</tt> keyword and the range definition within brackets.
3947: The <tt>Even</tt>, <tt>Odd</tt> and <tt>One</tt> are used to test a counter's
3948: value and are followed by the counter name between parentheses.</p>
1.30 cvs 3949:
3950: <p>The list of possible conditions on counters is:</p>
1.18 cvs 3951: <dl>
1.30 cvs 3952: <dt><tt>Even (Counter)</tt></dt>
3953: <dd>the box is created only if the counter has an even value.</dd>
3954: <dt><tt>Odd (Counter)</tt></dt>
3955: <dd>the box is created only if the counter has an odd value.</dd>
3956: <dt><tt>One (Counter)</tt></dt>
3957: <dd>the box is created only the counter's value is 1.</dd>
3958: <dt><tt>NOT One (Counter)</tt></dt>
3959: <dd>the box is created, unless the counter's value is 1.</dd>
3960: <dt><tt>(Counter < Value)</tt></dt>
3961: <dd>the box is created only if the counter's value is less than
3962: Value.</dd>
3963: <dt><tt>(Counter > Value)</tt></dt>
3964: <dd>the box is created only if the counter's value is greater than
3965: Value.</dd>
3966: <dt><tt>(Counter = Value)</tt></dt>
3967: <dd>the box is created only if the counter's value is equal to Value.</dd>
3968: <dt><tt>NOT (Counter = Value)</tt></dt>
3969: <dd>the is created only if the counter's value is different than
3970: Value.</dd>
3971: <dt><tt>(Counter IN [MinValue..MaxValue])</tt></dt>
3972: <dd>the box is created only if the counter's value falls in the range
3973: bounded by MinValue and MaxValue (inclusive).</dd>
3974: <dt><tt>NOT (Counter IN [MinValue..MaxValue])</tt></dt>
3975: <dd>the box is created only if the value of the counter does not fall in
3976: the range bounded by MinValue and MaxValue (inclusive).</dd>
1.18 cvs 3977: </dl>
1.30 cvs 3978:
3979: <p><strong>Note:</strong> the <tt>NOT Even</tt> and <tt>NOT Odd</tt>
3980: conditions are syntactically correct but can be expressed more simply by
3981: <tt>Odd</tt> and <tt>Even</tt>, respectively.</p>
1.18 cvs 3982: </div>
3983: </div>
1.1 cvs 3984:
1.18 cvs 3985: <div class="subsection">
1.30 cvs 3986: <h3><a name="sectc4215">A presentation rule</a></h3>
1.1 cvs 3987:
1.34 ! cvs 3988: <p>A presentation rule defines either a presentation property or presentation
! 3989: function. The properties are:</p>
1.18 cvs 3990: <ul>
1.30 cvs 3991: <li>the position of the vertical and horizontal reference axes of the
3992: box,</li>
3993: <li>the position of the box in relation to other boxes,</li>
3994: <li>the height or width of the box, with overflow exceptions,</li>
3995: <li>the margins, padding and borders of the box,</li>
3996: <li>the characteristics of the lines contained in the box: linespacing,
3997: indentation of the first line, justification, hyphenation,</li>
3998: <li>the conditions for breaking the box across pages,</li>
3999: <li>the characteristics of the characters contained in the box: size, font,
4000: style, underlining,</li>
4001: <li>the depth of the box among overlapping boxes (often called stacking
4002: order),</li>
4003: <li>the characteristics of graphic elements contained in the box: style and
4004: thickness of lines, fill pattern for closed objects,</li>
4005: <li>the colors in text, graphics, pictures, and symbols contained in the box
4006: are displayed or printed,</li>
4007: <li>for presentation boxes only, the contents of the box.</li>
4008: </ul>
4009:
4010: <p>The <a name="presfunct">presentation functions</a> are:</p>
4011: <ul>
4012: <li>the creation of a presentation box</li>
4013: <li>the line-breaking or page-breaking style,</li>
4014: <li>the copying of another box,</li>
4015: <li>the display of the box background and border,</li>
4016: <li>the display of a background picture and its aspect.</li>
4017: </ul>
4018:
1.34 ! cvs 4019: <p>For each box and each view, every presentation property is defined once and
! 4020: only once, either explicitly or by the <a href="#sectc427">default rules</a>.
! 4021: In contrast, presentation functions are not obligatory and can appear many
! 4022: times for the same element. for example an element can create many
! 4023: presentation boxes. Another element may not use any presentation
1.18 cvs 4024: functions.</p>
1.30 cvs 4025:
1.34 ! cvs 4026: <p>Each rule defining a presentation property begins with a keyword followed
! 4027: by a colon. The keyword indicates the property which is the subject of the
1.18 cvs 4028: rule. After the keyword and the colon, the remainder of the rule varies. All
4029: rules are terminated by a semicolon.</p>
1.34 ! cvs 4030: <pre> Rule = Property ';' / PresFunc ';' .
! 4031: Property ='VertRef' ':' PositionHoriz /
1.6 cvs 4032: 'HorizRef' ':' PositionVert /
4033: 'VertPos' ':' VPos /
4034: 'HorizPos' ':' HPos /
4035: 'Height' ':' Dimension /
4036: 'Width' ':' Dimension /
4037: 'VertOverflow' ':' Boolean /
1.1 cvs 4038: 'HorizOverflow' ':' Boolean /
1.26 cvs 4039: 'MarginTop' ':' MarginWidth /
4040: 'MarginRight' ':' MarginWidth /
4041: 'MarginBottom' ':' MarginWidth /
4042: 'MarginLeft' ':' MarginWidth /
4043: 'PaddingTop' ':' PaddingWidth /
4044: 'PaddingRight' ':' PaddingWidth /
4045: 'PaddingBottom' ':' PaddingWidth /
4046: 'PaddingLeft' ':' PaddingWidth /
4047: 'BorderTopWidth' ':' BorderWidth /
4048: 'BorderRightWidth' ':' BorderWidth /
4049: 'BorderBottomWidth' ':' BorderWidth /
4050: 'BorderLeftWidth' ':' BorderWidth /
4051: 'BorderTopColor' ':' BorderColor /
4052: 'BorderRightColor' ':' BorderColor /
4053: 'BorderBottomColor' ':' BorderColor /
4054: 'BorderLeftColor' ':' BorderColor /
4055: 'BorderTopStyle' ':' BorderStyle /
4056: 'BorderRightStyle' ':' BorderStyle /
4057: 'BorderBottomStyle' ':' BorderStyle /
4058: 'BorderLeftStyle' ':' BorderStyle .
1.6 cvs 4059: 'LineSpacing' ':' DistanceInherit /
4060: 'Indent' ':' DistanceInherit /
4061: 'Adjust' ':' AdjustInherit /
4062: 'Justify' ':' BoolInherit /
4063: 'Hyphenate' ':' BoolInherit /
4064: 'PageBreak' ':' Boolean /
4065: 'LineBreak' ':' Boolean /
4066: 'InLine' ':' Boolean /
4067: 'NoBreak1' ':' AbsDist /
4068: 'NoBreak2' ':' AbsDist /
4069: 'Gather' ':' Boolean /
4070: 'Visibility' ':' NumberInherit /
4071: 'Size' ':' SizeInherit /
4072: 'Font' ':' NameInherit /
4073: 'Style' ':' StyleInherit /
1.23 cvs 4074: 'Weight' ':' WeightInherit /
1.6 cvs 4075: 'Underline' ':' UnderLineInherit /
4076: 'Thickness' ':' ThicknessInherit /
4077: 'Depth' ':' NumberInherit /
4078: 'LineStyle' ':' LineStyleInherit /
4079: 'LineWeight' ':' DistanceInherit /
4080: 'FillPattern' ':' NameInherit /
4081: 'Background' ':' NameInherit /
1.13 cvs 4082: 'Foreground' ':' NameInherit /
1.6 cvs 4083: 'Content' ':' VarConst .
1.1 cvs 4084: PresFunc = Creation '(' BoxID ')' /
4085: 'Line' /
4086: 'NoLine' /
4087: 'Page' '(' BoxID ')' /
1.13 cvs 4088: 'Copy' '(' BoxTypeToCopy ')' /
4089: 'ShowBox' /
1.18 cvs 4090: 'BackgroundPicture' ':' FileName /
4091: 'PictureMode' ':' PictMode /</pre>
4092: </div>
4093:
4094: <div class="subsection">
1.30 cvs 4095: <h3><a name="sectc4216">Box axes</a></h3>
1.18 cvs 4096:
1.30 cvs 4097: <p>The position of the middle axes <tt>VMiddle</tt> and <tt>HMiddle</tt> in
1.1 cvs 4098: relation to their box is always calculated automatically as a function of the
4099: height and width of the box and is not specified by the presentation rules. In
4100: the presentation schema, these middle axes are used only to position their box
4101: with respect to another by specifying the distance between the middle axis and
1.18 cvs 4102: an axis or a side of another box (see the <a href="#sectc4218">relative
4103: position</a>).</p>
1.30 cvs 4104:
4105: <p>The reference axes of a box are also used to position their box in relation
4106: to another, but in contrast to the middle axes, the presentation schema must
4107: make their position explicit, either in relation to a side or the middle axis
4108: of the box itself, or in relation to an axis of an enclosed box.</p>
4109:
4110: <p>Only boxes of base elements have predefined reference axes. For character
1.1 cvs 4111: string boxes, the horizontal reference axis is the baseline of the characters
4112: (the line which passes immediately under the upper-case letters, ignoring the
4113: letter Q) and the vertical reference axis is at the left edge of the first
1.18 cvs 4114: character of the string.</p>
1.30 cvs 4115:
4116: <p>The positions of a box's reference axes are defined by the <tt>VertRef</tt>
1.18 cvs 4117: and <tt>HorizRef</tt> rules which specify the <a href="#distance">distance</a>
1.1 cvs 4118: between the reference axis and an axis or parallel side of the same box or of
1.18 cvs 4119: an enclosed box.</p>
4120: <pre> 'VertRef' ':' PositionHoriz
4121: 'HorizRef' ':' PositionVert</pre>
1.30 cvs 4122:
1.18 cvs 4123: <blockquote class="example">
1.30 cvs 4124: <p><strong>Example:</strong></p>
4125:
4126: <p>If, in the structure schema for mathematical formulas, the fraction
4127: element is defined by</p>
4128: <pre>Fraction = BEGIN
1.1 cvs 4129: Numerator = Expression;
4130: Denominator = Expression;
1.18 cvs 4131: END;</pre>
1.30 cvs 4132:
4133: <p>then the horizontal reference axis of the fraction can be positioned on
4134: top of the denominator by the rule:</p>
4135: <pre>Fraction :
1.1 cvs 4136: BEGIN
4137: HorizRef : Enclosed Denominator . Top;
4138: ...
1.18 cvs 4139: END;</pre>
1.30 cvs 4140:
4141: <p>To put the horizontal reference axis of a column at its middle:</p>
4142: <pre>Column :
1.1 cvs 4143: BEGIN
4144: HorizRef : * . HMiddle;
4145: ...
1.18 cvs 4146: END;</pre>
4147: </blockquote>
4148: </div>
1.1 cvs 4149:
1.18 cvs 4150: <div class="subsection">
1.30 cvs 4151: <h3><a name="sectc4217">Distance units</a></h3>
1.1 cvs 4152:
1.30 cvs 4153: <p>Some distances and dimensions appear in many rules of a presentation
4154: schema, especially in position rules (<tt>VertPos, HorizPos</tt>), in extent
4155: rules for boxes (<tt>Height, Width</tt>), in rules defining lines
4156: (<tt>LineSpacing, Indent</tt>), in rules controlling pagination (<tt>NoBreak1,
4157: NoBreak2</tt>) and in rules specifying the thickness of strokes
4158: (<tt>LineWeight</tt>).</p>
4159:
4160: <p>In all these rules, the distance or extent can be expressed</p>
4161: <ul>
4162: <li>either in relative units, which depend on the size of the characters in
4163: the current font: height of the element's font or height of the letter
4164: 'x',</li>
4165: <li>or in absolute units: centimeter, millimeter, inch, typographer's point,
4166: pica or pixel.</li>
4167: </ul>
4168:
4169: <p>Units can be chosen freely. Thus, it is possible to use relative units in
4170: one rule, centimeters in the next rule, and typographer's points in
4171: another.</p>
4172:
4173: <p>Absolute units are used to set rigid rules for the appearance of documents.
4174: In contrast, relative units allow changes of scale. The editor lets the value
4175: of relative units be changed dynamically. Such changes affect every box using
1.1 cvs 4176: relative units simultaneously and in the same proportion. Changing the value
4177: of the relative units affects the size of the characters and graphical
1.18 cvs 4178: elements, and the size of the boxes and the distances between them.</p>
1.30 cvs 4179:
4180: <p>A <a name="distance">distance</a> or extent is specified by a number, which
1.1 cvs 4181: may be followed by one or more spaces and a units keyword. When there is no
4182: units keyword, the number specifies the number of relative units, where a
4183: relative unit is the height of a character in the current font (an em). When
4184: the number is followed by a units keyword, the keyword indicates the type of
1.18 cvs 4185: absolute units:</p>
4186: <ul>
1.30 cvs 4187: <li><tt>em</tt>: height of the element's font,</li>
4188: <li><tt>ex</tt>: height of the letter 'x',</li>
4189: <li><tt>cm</tt>: centimeter,</li>
4190: <li><tt>mm</tt>: millimeter,</li>
4191: <li><tt>in</tt>: inch (1 in = 2.54 cm),</li>
4192: <li><tt>pt</tt>: point (1 pt = 1/72 in),</li>
4193: <li><tt>pc</tt>: pica (1 pc = 12 pt),</li>
4194: <li><tt>px</tt>: pixel.</li>
1.18 cvs 4195: </ul>
1.30 cvs 4196:
4197: <p>Whatever the chosen unit, relative or absolute, the number is not
4198: necessarily an integer and may be expressed in fixed point notation (using the
4199: American convention of a period to express the decimal point).</p>
4200:
4201: <p>If the distance appears in a presentation rule for a numeric attribute, the
1.1 cvs 4202: number can be replaced by the name of an attribute. In this case, the value
4203: of the attribute is used. Obviously, the attribute name cannot be followed by
4204: a decimal point and a fractional part, but it can be followed a units keyword.
1.18 cvs 4205: However, the choice of units is limited to em, ex, pt and px.</p>
4206: <pre> Distance = [ Sign ] AbsDist .
1.1 cvs 4207: Sign ='+' / '-' .
4208: AbsDist = IntegerOrAttr [ '.' DecimalPart ]
4209: [ Unit ].
4210: IntegerOrAttr = IntegerPart / AttrID .
4211: IntegerPart = NUMBER .
4212: DecimalPart = NUMBER .
4213: Unit ='em' / 'ex' / 'cm' / 'mm' / 'in' / 'pt' /
1.18 cvs 4214: 'pc' / 'px' / '%' .</pre>
1.30 cvs 4215:
1.18 cvs 4216: <blockquote class="example">
1.30 cvs 4217: <p><strong>Example:</strong></p>
4218:
4219: <p>The following rules specify that a box has a height of 10.5 centimeters
4220: and a width of 5.3 ems:</p>
4221: <pre>Height : 10.5 cm;
1.18 cvs 4222: Width : 5.3;</pre>
4223: </blockquote>
4224: </div>
1.1 cvs 4225:
1.18 cvs 4226: <div class="subsection">
1.30 cvs 4227: <h3><a name="sectc4218">Relative positions</a></h3>
1.1 cvs 4228:
1.30 cvs 4229: <p>The positioning of boxes uses the eight axes and sides, the sides generally
1.1 cvs 4230: being used to define the juxtapositioning (vertical or horizontal) of boxes,
4231: the middle axes being used to define centering, and the reference axes being
1.18 cvs 4232: used for alignment.</p>
1.30 cvs 4233:
4234: <p>Two rules allow a box to be placed relative to other boxes. The
1.18 cvs 4235: <tt>VertPos</tt> rule positions the box vertically. The <tt>HorizPos</tt>
4236: rule positions the box horizontally. It is possible that a box's position
4237: could be entirely determined by other boxes positioned relative to it. In this
4238: case, the position is implicit and the word <tt>nil</tt> can be used to
4239: specify that no position rule is needed. Otherwise, an explicit rule must be
4240: given by indicating the axis or side which defines the position of the box,
4241: followed by an equals sign and the distance between between this axis or side
4242: and a parallel axis or side of another box, called the reference box. The box
4243: for which the rule is written will be positioned relative to the reference
4244: box.</p>
4245: <pre> 'VertPos' ':' VPos
1.6 cvs 4246: 'HorizPos' ':' HPos
4247: HPos = 'nil' / VertAxis '=' HorizPosition
4248: [ 'UserSpecified' ].
4249: VPos = 'nil' / HorizAxis '=' VertPosition
4250: [ 'UserSpecified' ].
1.1 cvs 4251: VertAxis = 'Left' / 'VMiddle' / 'VRef' / 'Right' .
1.18 cvs 4252: HorizAxis = 'Top' / 'HMiddle' / 'HRef' / 'Bottom' .</pre>
1.30 cvs 4253:
4254: <p>The reference box is an adjacent box: enclosing, enclosed or adjacent. When
4255: a rule is associated with a reference type attribute (and only in this case),
4256: it can be a box of the element designated by the attribute. The reference box
1.18 cvs 4257: can be either a presentation box previously defined in the <tt>BOXES</tt>
1.1 cvs 4258: section of the schema and created by a creation function, or the box
1.18 cvs 4259: associated with a structured element.</p>
1.30 cvs 4260:
4261: <p>The structural position of the reference box (relative to the box for which
1.18 cvs 4262: the rule is being written) is indicated by a keyword: <tt>Enclosing</tt>,
4263: <tt>Enclosed</tt>, or, for sibling boxes, <tt>Previous</tt> or <tt>Next</tt>.
1.1 cvs 4264: The reference attributes, or presentation boxes created by a reference
1.18 cvs 4265: attribute, the <tt>Referred</tt> keyword may be used to designate the element
4266: which the reference points to. The keyword <tt>Creator</tt> can be used in
1.1 cvs 4267: rules for presentation boxes to designate the box of the element which created
1.18 cvs 4268: the presentation box. Finally, the <tt>Root</tt> keyword can be used to
4269: designate the root of the document.</p>
1.30 cvs 4270:
4271: <p>When the keyword is ambiguous, it is followed by the name of an element
4272: type or presentation box which resolves the ambiguity (the <tt>Creator</tt>
4273: and <tt>Root</tt> keywords are never ambiguous). If this name is not given,
4274: then the first box encountered is used as the reference box. It is also
4275: possible to use just the name of an element type or presentation box without
4276: an initial keyword. In this case, a sibling having that name will be used. If
4277: the name is preceded by the keyword <tt>NOT</tt>, then the reference box will
4278: be the first box whose type is not the named one.</p>
4279:
4280: <p>In place of the box or type name, the keywords <tt>AnyElem</tt>,
1.18 cvs 4281: <tt>AnyBox</tt> and <tt>ElemWithAttr</tt> can be used, representing
1.17 cvs 4282: respectively, any structured element box, any presentation box, and the box
4283: corresponding to any structured element having a particular attribute,
4284: whatever its value; the name of this attribute must follow the keyword
1.18 cvs 4285: <tt>ElemWithAttr</tt>.</p>
1.30 cvs 4286:
4287: <p>A type name may be preceded by a star in order to resolve the ambiguity in
4288: the special case where the structure schema defines an <a
1.18 cvs 4289: href="#sectd3284">inclusion</a> without expansion (or with partial expansion)
4290: of the same type as an element of the scheme. For mark pairs (and only for <a
4291: href="#sectd3285">mark pairs</a>) the type name <em>must</em> be preceded by
4292: the <tt>First</tt> or <tt>Second</tt> keyword, which indicates which of the
4293: two marks of the pair should be used as the reference box.</p>
1.30 cvs 4294:
4295: <p>The star character ('<tt>*</tt>') used alone designates the box to which
4296: the rule applies (in this case, it is obviously useless to specify the type of
4297: the reference box).</p>
4298:
4299: <p>The keywords <tt>Enclosing</tt> and <tt>Enclosed</tt> can be used no matter
1.1 cvs 4300: what constructor defines the type to which the rule applies. When applied to
1.18 cvs 4301: the element which represents the entire document, <tt>Enclosing</tt>
1.1 cvs 4302: designates the window or page in which the document's image is displayed for
4303: the view to which the rule applies. A box or type name without a keyword is
4304: used for aggregate elements and designates another element of the same
4305: aggregate. It can also be used to designate a presentation or page layout
1.18 cvs 4306: box. The keywords <tt>Previous</tt> and <tt>Next</tt> are primarily used to
1.1 cvs 4307: denote list elements, but can also be used to denote elements of an
1.18 cvs 4308: aggregate.</p>
1.30 cvs 4309:
4310: <p>In the position rule, the structural position relative to the reference box
4311: is followed, after a period, by the name of an axis or side. The rule
4312: specifies its node's position as being some distance from this axis or side of
4313: the reference box. If this distance is zero, then the distance does not
4314: appear in the rule. Otherwise, it does appear as a positive or negative
4315: number (the sign is required for negative numbers). The sign takes into
4316: account the orientation of the coordinate axes: for top to bottom for the
4317: vertical axis and from left to right for the horizontal axis. Thus, a
4318: negative distance in a vertical position indicates that the side or axis
4319: specified in the rule is above the side or axis of the reference box.</p>
4320:
4321: <p>The distance can be followed by the <tt>UserSpecified</tt> keyword (even if
1.18 cvs 4322: the distance is nil and does not appear, the <tt>UserSpecified</tt> keyword
1.1 cvs 4323: can be used). It indicates that when the element to which the rule applies is
4324: being created, the editor will ask the user to specify the distance himself,
4325: using the mouse. In this case, the distance specified in the rule is a
4326: default distance which is suggested to the user but can be modified. The
1.18 cvs 4327: <tt>UserSpecified</tt> keyword can be used either in the vertical position
4328: rule, the horizontal position rule, or both.</p>
4329: <pre> VertPosition = Reference '.' HorizAxis [ Distance ] .
1.1 cvs 4330: HorizPosition = Reference '.' VertAxis [ Distance ] .
4331: Reference ='Enclosing' [ BoxTypeNot ] /
4332: 'Enclosed' [ BoxTypeNot ] /
4333: 'Previous' [ BoxTypeNot ] /
4334: 'Next' [ BoxTypeNot ] /
4335: 'Referred' [ BoxTypeNot ] /
4336: 'Creator' /
4337: 'Root' /
4338: '*' /
4339: BoxOrType .
4340: BoxOrType = BoxID /
4341: [ '*' ] [ FirstSec ] ElemID /
1.17 cvs 4342: 'AnyElem' / 'AnyBox' /
4343: 'ElemWithAttr' AttrID .
1.18 cvs 4344: BoxTypeNot = [ 'NOT' ] BoxOrType .</pre>
1.30 cvs 4345:
1.18 cvs 4346: <blockquote class="example">
1.30 cvs 4347: <p><strong>Example:</strong></p>
4348:
4349: <p>If a <a name="expos1">report</a> is defined by the following structure
4350: schema:</p>
4351: <pre>Report = BEGIN
1.6 cvs 4352: Title = Text;
4353: Summary = Text;
4354: Keywords = Text;
4355: ...
1.18 cvs 4356: END;</pre>
1.30 cvs 4357:
4358: <p>then the presentation schema could contain the rules:</p>
4359: <pre>Report : BEGIN
1.6 cvs 4360: VertPos : Top = Enclosing . Top;
4361: HorizPos : Left = Enclosing . Left;
4362: ...
1.18 cvs 4363: END;</pre>
1.30 cvs 4364:
4365: <p>These rules place the <a name="reportexample">report</a> in the upper
4366: left corner of the enclosing box, which is the window in which the document
4367: is being edited.</p>
4368: <pre>Title : BEGIN
1.6 cvs 4369: VertPos : Top = Enclosing . Top + 1;
4370: HorizPos : VMiddle = Enclosing . VMiddle;
4371: ...
1.18 cvs 4372: END;</pre>
1.30 cvs 4373:
4374: <p>The top of the title is one line (a line has the height of the characters
4375: of the title) from the top of the report, which is also the top of the
4376: editing window. The title is centered horizontally in the window (see <a
4377: href="#posdim">figure</a>).</p>
4378: <pre>Summary : BEGIN
1.1 cvs 4379: VertPos : Top = Title . Bottom + 1.5;
4380: HorizPos : Left = Enclosing . Left + 2 cm;
4381: ...
1.18 cvs 4382: END;</pre>
1.30 cvs 4383:
4384: <p>The top of the summary is place a line and a half below the bottom of the
4385: title and is shifted two centimeters from the side of the window.</p>
1.18 cvs 4386: </blockquote>
1.30 cvs 4387:
1.18 cvs 4388: <blockquote class="example">
1.30 cvs 4389: <p><strong>Example:</strong></p>
4390:
4391: <p>Suppose there is a <a name="expos2">Design</a> logical structure which
4392: contains graphical elements:</p>
4393: <pre>Design = LIST OF (ElemGraph = GRAPHICS);</pre>
4394:
4395: <p>The following rules allow the user to freely choose the position of each
4396: element when it is created:</p>
4397: <pre>ElemGraph =
1.1 cvs 4398: BEGIN
4399: VertPos : Top = Enclosing . Top + 1 cm UserSpecified;
4400: HorizPos: Left = Enclosing . Left UserSpecified;
4401: ...
1.18 cvs 4402: END;</pre>
1.30 cvs 4403:
4404: <p>Thus, when a graphical element is created, its default placement is at
4405: the left of the window and 1 cm from the top, but the user can move it
4406: immediately, simply by moving the mouse.</p>
1.18 cvs 4407: </blockquote>
4408: </div>
1.1 cvs 4409:
1.18 cvs 4410: <div class="subsection">
1.30 cvs 4411: <h3><a name="sectc4219">Box extents</a></h3>
1.1 cvs 4412:
1.30 cvs 4413: <p>The extents (height and width) of each box are defined by the two rules
1.18 cvs 4414: <tt>Height</tt> and <tt>Width</tt>. There are three types of extents: fixed,
4415: relative, and elastic.</p>
1.1 cvs 4416:
1.18 cvs 4417: <div class="subsubsection">
1.30 cvs 4418: <h4><a name="sectd42191">Fixed extents</a></h4>
1.1 cvs 4419:
1.30 cvs 4420: <p>A fixed dimension sets the height or width of the box independently of all
1.18 cvs 4421: other boxes. It is expressed in <a href="#sectc4217">distance units</a>. The
4422: extent can be followed by the <tt>UserSpecified</tt> keyword which indicates
1.1 cvs 4423: that when the element to which the rule applies is being created, the editor
4424: will ask the user to specify the extent himself, using the mouse. In this
4425: case, the extent specified in the rule is a default extent which is suggested
1.18 cvs 4426: to the user but can be modified. The <tt>UserSpecified</tt> keyword can be
4427: used either in the <tt>Height</tt> rule, the <tt>Width</tt> rule, or both.</p>
1.30 cvs 4428:
4429: <p>A fixed extent rule can be ended by the <tt>Min</tt> keyword, which
4430: signifies that the indicated value is a minimum, and that, if the contents of
4431: the box require it, a larger extent is possible.</p>
1.18 cvs 4432: <pre> 'Height' ':' Dimension
1.1 cvs 4433: 'Width' ':' Dimension
4434: Dimension = AbsDist [ 'UserSpecified' ] [ 'Min' ] /
1.18 cvs 4435: ...</pre>
1.30 cvs 4436:
1.18 cvs 4437: <blockquote class="example">
1.30 cvs 4438: <p><strong>Example:</strong></p>
4439:
4440: <p>Continuing with the <a href="#expos2">previous example</a>, it is
4441: possible to allow the user to choose the size of each graphical element as
4442: it is created:</p>
4443: <pre>ElemGraph : BEGIN
1.6 cvs 4444: Width : 2 cm UserSpecified;
1.1 cvs 4445: Height : 1 cm UserSpecified;
4446: ...
1.18 cvs 4447: END;</pre>
1.30 cvs 4448:
4449: <p>Thus, when a graphical element is create, it is drawn by default with a
4450: width of 2 cm and a height of 1 cm, but the user is free to resize it
4451: immediately with the mouse.</p>
4452: <pre>Summary : BEGIN
1.1 cvs 4453: Height : 5 cm Min;
4454: ...
4455: END;
4456: Keywords : BEGIN
4457: VertPos : Top = Summary . Bottom;
4458: ...
1.18 cvs 4459: END;</pre>
4460: </blockquote>
4461: </div>
1.1 cvs 4462:
1.18 cvs 4463: <div class="subsubsection">
1.30 cvs 4464: <h4><a name="sectd42192">Relative extents</a></h4>
4465:
4466: <p>A relative extent determines the extent as a function of the extent of
4467: another box, just as a relative position places a box in relation to another.
4468: The reference box in an extent rule is designated using the same syntax as is
4469: used in a relative position rule. It is followed by a period and a
4470: <tt>Height</tt> or <tt>Width</tt> keyword, depending on the extent being
4471: referred to. Next comes the relation between the extent being defined and the
4472: extent of the reference box. This relation can be either a percentage or a
4473: difference.</p>
1.1 cvs 4474:
1.30 cvs 4475: <p>A percentage is indicated by a star (the multiplication symbol) followed by
1.1 cvs 4476: the numeric percentage value (which may be greater than or less than 100) and
4477: the percent (`%') character. A difference is simply indicated by a signed
1.18 cvs 4478: difference.</p>
1.30 cvs 4479:
4480: <p>If the rule appears in the presentation rules of a numeric attribute, the
1.1 cvs 4481: percentage value can be replaced by the name of the attribute. This attribute
1.18 cvs 4482: is then used as a percentage. The attribute can also be used as part of a <a
4483: href="#distance">difference</a>.</p>
1.30 cvs 4484:
4485: <p>Just as with a fixed extent, a relative extent rule can end with the
1.18 cvs 4486: <tt>Min</tt> keyword, which signifies that the extent is a minimum and that,
4487: if the contents of the box require it, a larger extent is possible.</p>
1.30 cvs 4488:
4489: <p>A special case of relative extent rules is:</p>
1.18 cvs 4490: <pre>Height : Enclosed . Height;</pre>
1.30 cvs 4491:
4492: <p>or</p>
1.18 cvs 4493: <pre>Width : Enclosed . Width;</pre>
1.30 cvs 4494:
4495: <p>which specifies that the box has a height (or width) such that it encloses
4496: all the boxes which it contains, excluding boxes having a rule
4497: <tt>VertOverflow: Yes;</tt> or <tt>HorizOverflow: Yes;</tt>.</p>
4498:
4499: <p><strong>Note:</strong> character strings (type <tt>TEXT_UNIT</tt>)
4500: generally must use the sum of the widths of the characters which compose them
4501: as their width, which is expressed by the rule:</p>
1.18 cvs 4502: <pre>TEXT_UNIT :
4503: Width : Enclosed . Width;</pre>
1.30 cvs 4504:
4505: <p>If this rule is not the default <tt>Width</tt> rule, it must be given
1.18 cvs 4506: explicitly in the <tt>RULES</tt> section which defines the presentation rules
4507: of the logical elements.</p>
4508: <pre> 'Height' ':' Extent
1.1 cvs 4509: 'Width' ':' Extent
4510: Extent = Reference '.' HeightWidth [ Relation ]
4511: [ 'Min' ] / ...
4512: HeightWidth ='Height' / 'Width' .
4513: Relation ='*' ExtentAttr '%' / Distance .
4514: ExtentAttr = ExtentVal / AttrID .
1.18 cvs 4515: ExtentVal = NUMBER .</pre>
1.30 cvs 4516:
1.18 cvs 4517: <blockquote class="example">
1.30 cvs 4518: <p><strong>Example:</strong></p>
4519:
4520: <p>Completing the <a href="#expos1">above example</a>, it is possible to
4521: specify that the report takes its width from the editing window and its
4522: height from the size of its contents (this can obviously be greater than
4523: that of the window):</p>
4524: <pre>Report : BEGIN
1.1 cvs 4525: Width : Enclosing . Width;
4526: Height : Enclosed . Height;
4527: ...
1.18 cvs 4528: END;</pre>
1.30 cvs 4529:
4530: <p>Then, the following rules make the title occupy 60% of the width of the
4531: report (which is that of the window) and is broken into centered lines of
4532: this width (see the <a href="#sectc4222"><tt>Line</tt> rule</a>).</p>
4533: <pre>Title : BEGIN
1.1 cvs 4534: Width : Enclosing . Width * 60%;
4535: Height : Enclosed . Height;
4536: Line;
4537: Adjust : VMiddle;
4538: ...
1.18 cvs 4539: END;</pre>
1.30 cvs 4540:
4541: <p>The summary occupy the entire width of the window, with the exception of
4542: a 2 cm margin reserved by the horizontal position rule:</p>
4543: <pre>Summary : BEGIN
1.1 cvs 4544: Width : Enclosing . Width - 2 cm;
4545: Height : Enclosed . Height;
4546: ...
1.18 cvs 4547: END;</pre>
4548:
1.30 cvs 4549: <p>This set of rules, plus the <a href="#reportexample">position rules given
4550: above</a>, produce the layout of boxes shown in the following<a
4551: href="#posdim">figure</a>.</p>
4552:
4553: <div class="figure">
4554: <hr>
4555: <pre>-------------------------------------------------------------
1.1 cvs 4556: | Window and Report ^ |
4557: | | 1 line |
4558: | v |
4559: | ------------------------------------- |
4560: | | | |
4561: : 20% : Title : 20% :
1.30 cvs 4562: :<--------->: :<--------->:
1.1 cvs 4563: : : 60% : :
1.30 cvs 4564: : :<--------------------------------->: :
1.1 cvs 4565: | | | |
4566: | ------------------------------------- |
4567: | ^ |
4568: | | 1.5 line |
4569: | | |
4570: | v |
4571: | ---------------------------------------------------|
4572: | 2 cm | |
1.30 cvs 4573: |<------>| Summary |
1.18 cvs 4574: : : :</pre>
1.19 cvs 4575:
1.30 cvs 4576: <p align="center"><em><a name="posdim">Box position and
4577: extent</a><em></em></em></p>
4578: <hr>
4579: </div>
1.18 cvs 4580: </blockquote>
4581: </div>
1.1 cvs 4582:
1.18 cvs 4583: <div class="subsubsection">
1.30 cvs 4584: <h4><a name="sectd42193">Elastic extents</a></h4>
1.1 cvs 4585:
1.30 cvs 4586: <p>The last type of extent is the elastic extent. Either one or both extents
4587: can be elastic. A box has an elastic extent when two opposite sides are
4588: linked by distance constraints to two sides or axes of other boxes.</p>
4589:
4590: <p>One of the sides of the elastic box is linked by a position rule
1.18 cvs 4591: (<tt>VertPos</tt> or <tt>HorizPos</tt>) to a neighboring box. The other side
4592: is link to another box by a <tt>Height</tt> or <tt>Width</tt> rule, which
1.1 cvs 4593: takes the same form as the position rule. For the elastic box itself, the
4594: notions of sides (left or right, top or bottom) are fuzzy, since the movement
4595: of either one of the two reference boxes can, for example, make the left side
4596: of the elastic box move to the right of its right side. This is not
4597: important. The only requirement is that the two sides of the elastic box used
1.18 cvs 4598: in the position and extent rule are opposite sides of the box.</p>
4599: <pre> 'Height' ':' Extent
1.6 cvs 4600: 'Width' ':' Extent
1.18 cvs 4601: Extent = HPos / VPos / ...</pre>
1.30 cvs 4602:
1.18 cvs 4603: <blockquote class="example">
1.30 cvs 4604: <p><strong>Example:</strong></p>
4605:
4606: <p>Suppose we want to draw an elastic arrow or line between the middle of
4607: the bottom side of box A and the upper left corner of box B. To do this, we
4608: would define a graphics box whose upper left corner coincides with the
4609: middle of the bottom side of A (a position rule) and whose lower right
4610: corner coincides with with the upper left corner of B (dimension rules):</p>
4611: <pre>LinkedBox :
1.1 cvs 4612: BEGIN
1.6 cvs 4613: VertPos : Top = A .Bottom;
1.1 cvs 4614: HorizPos : Left = A . VMiddle;
1.6 cvs 4615: Height : Bottom = B . Top;
4616: Width : Right = B . Left;
1.18 cvs 4617: END;</pre>
4618: </blockquote>
1.30 cvs 4619:
1.18 cvs 4620: <blockquote class="example">
1.30 cvs 4621: <p><strong>Example:</strong></p>
4622:
4623: <p>The element SectionTitle creates a presentation box called SectionNum
4624: which contains the number of the section. Suppose we want to align the
4625: SectionNum and SectionTitle horizontally, have the SectionNum take its width
4626: from its contents (the section number), have the SectionTitle box begin 0.5
4627: cm to the right of the SectionNum box and end at the right edge of its
4628: enclosing box. This would make the SectionTitle box elastic, since its width
4629: is defined by the position of its left and right sides. The following rules
4630: produce this effect:</p>
4631: <pre>SectionNum :
1.1 cvs 4632: BEGIN
4633: HorizPos : Left = Enclosing . Left;
4634: Width : Enclosed . Width;
4635: ...
4636: END;
4637:
4638: SectionTitle :
4639: BEGIN
4640: HorizPos : Left = SectionNum . Right + 0.5 cm;
4641: Width : Right = Enclosing . Right;
4642: ...
1.18 cvs 4643: END;</pre>
4644: </blockquote>
4645: </div>
4646: </div>
1.1 cvs 4647:
1.18 cvs 4648: <div class="subsection">
1.30 cvs 4649: <h3><a name="sectc4220">Overflow</a></h3>
1.1 cvs 4650:
1.30 cvs 4651: <p>A boxes corresponding to a structural element normally contain all boxes
1.1 cvs 4652: corresponding to the elements of its subtree. However, in some cases, it
4653: could be necessary to allow a box to jut out from its parent box. Two
4654: presentation rules indicate that such an overflow is allowed, one for
1.18 cvs 4655: horizontal overflow, one for vertical overflow.</p>
1.30 cvs 4656:
4657: <p>Each of these rules is expressed by a keyword followed by a colon and the
1.18 cvs 4658: keyword <tt>Yes</tt> or <tt>No</tt>.</p>
4659: <pre> 'VertOverflow' ':' Boolean /
1.1 cvs 4660: 'HorizOverflow' ':' Boolean .
1.18 cvs 4661: Boolean = 'Yes' / 'No' .</pre>
4662: </div>
1.1 cvs 4663:
1.30 cvs 4664: <p>@@@@@ ******</p>
4665:
1.26 cvs 4666: <p>Explain Margin, Padding and Border. Refer to CSS2.</p>
4667: <pre> 'MarginTop' ':' MarginWidth /
4668: 'MarginRight' ':' MarginWidth /
4669: 'MarginBottom' ':' MarginWidth /
4670: 'MarginLeft' ':' MarginWidth /
4671: 'PaddingTop' ':' PaddingWidth /
4672: 'PaddingRight' ':' PaddingWidth /
4673: 'PaddingBottom' ':' PaddingWidth /
4674: 'PaddingLeft' ':' PaddingWidth /
4675: 'BorderTopWidth' ':' BorderWidth /
4676: 'BorderRightWidth' ':' BorderWidth /
4677: 'BorderBottomWidth' ':' BorderWidth /
4678: 'BorderLeftWidth' ':' BorderWidth /
4679: 'BorderTopColor' ':' BorderColor /
4680: 'BorderRightColor' ':' BorderColor /
4681: 'BorderBottomColor' ':' BorderColor /
4682: 'BorderLeftColor' ':' BorderColor /
4683: 'BorderTopStyle' ':' BorderStyle /
4684: 'BorderRightStyle' ':' BorderStyle /
4685: 'BorderBottomStyle' ':' BorderStyle /
4686: 'BorderLeftStyle' ':' BorderStyle .
4687:
4688: MarginWidth = InheritParent / 'Auto' / Distance .
4689: PaddingWidth = InheritParent / Distance .
4690: BorderWidth = InheritParent / 'Thin' / 'Medium' / 'Thick' / Distance .
4691: BorderColor = InheritParent / 'Transparent' / 'Foreground' /
4692: ColorName .
4693: BorderStyle = InheritParent /
4694: 'None' / 'Hidden' / 'Dotted' / 'Dashed' / 'Solid' /
4695: 'Double' / 'Groove' / 'Ridge' / 'Inset' / 'Outset' .
1.27 cvs 4696: InheritParent = 'Enclosing' '=' / 'Creator' '=' .
1.26 cvs 4697: ColorName = NAME .</pre>
1.30 cvs 4698:
4699: <p>@@@@@ ******</p>
1.26 cvs 4700:
1.18 cvs 4701: <div class="subsection">
1.30 cvs 4702: <h3><a name="sectc4221">Inheritance</a></h3>
1.1 cvs 4703:
1.34 ! cvs 4704: <p>A presentation property can be defined by reference to the same property of
! 4705: another box in the tree of boxes. These structural links are expressed by
1.1 cvs 4706: kinship. The reference box can be that of the element immediately above in
1.18 cvs 4707: the structure (<tt>Enclosing</tt>), two levels above (<tt>GrandFather</tt>),
4708: immediately below (<tt>Enclosed</tt>) or immediately before
4709: (<tt>Previous</tt>). In the case of a presentation box, and only in that
1.1 cvs 4710: case, the reference box may be the element which created the presentation box
1.18 cvs 4711: (<tt>Creator</tt>).</p>
1.30 cvs 4712:
4713: <p>Kinship is expressed in terms of the logical structure of the document and
4714: not in terms of the tree of boxes. The presentation box cannot transmit any
1.34 ! cvs 4715: of their properties by inheritance; only structured element boxes can do so.
1.30 cvs 4716: As an example, consider an element B which follows an element A in the logical
1.1 cvs 4717: structure. The element B creates a presentation box P in front of itself,
1.18 cvs 4718: using the <tt>CreateBefore</tt> rule (see the <a href="#sectc4232">creation
4719: rules</a>). If element B's box inherits its character style using the
4720: <tt>Previous</tt> kinship operation, it gets its character style from A's box,
1.1 cvs 4721: not from P's box. Inheritance works differently for positions and extents,
1.18 cvs 4722: which can refer to presentation boxes.</p>
1.30 cvs 4723:
1.34 ! cvs 4724: <p>The inherited property value can be the same as that of the reference box.
! 4725: This is indicated by an equals sign. However, for numeric properties, a
1.1 cvs 4726: different value can be obtained by adding or subtracting a number from the
1.34 ! cvs 4727: reference box's property value. Addition is indicated by a plus sign before
1.1 cvs 4728: the number, while subtraction is specified with a minus sign. The value of a
1.34 ! cvs 4729: property can also be given a maximum (if the sign is a plus) or minimum (if
1.18 cvs 4730: the sign is a minus).</p>
1.30 cvs 4731:
4732: <p>If the rule is being applied to a numeric attribute, the number to add or
1.1 cvs 4733: subtract can be replaced by the attribute name. The value of a maximum or
4734: minimum may also be replaced by an attribute name. In these cases, the value
1.18 cvs 4735: of the attribute is used.</p>
4736: <pre> Inheritance = Kinship InheritedValue .
1.6 cvs 4737: Kinship ='Enclosing' / 'GrandFather' / 'Enclosed' /
4738: 'Previous' / 'Creator' .
1.1 cvs 4739: InheritedValue ='+' PosIntAttr [ 'Max' maximumA ] /
1.6 cvs 4740: '-' NegIntAttr [ 'Min' minimumA ] /
4741: '=' .
4742: PosIntAttr = PosInt / AttrID .
4743: PosInt = NUMBER .
4744: NegIntAttr = NegInt / AttrID .
4745: NegInt = NUMBER .
4746: maximumA = maximum / AttrID .
4747: maximum = NUMBER .
4748: minimumA = minimum / AttrID .
1.18 cvs 4749: minimum = NUMBER .</pre>
1.30 cvs 4750:
1.34 ! cvs 4751: <p>The properties which can be obtained by inheritance are justification,
1.1 cvs 4752: hyphenation, interline spacing, character font (font family), font style, font
4753: size, visibility, indentation, underlining, alignment of text, stacking order
4754: of objects, the style and thickness of lines, fill pattern and the colors of
1.18 cvs 4755: lines and characters.</p>
4756: </div>
1.1 cvs 4757:
1.18 cvs 4758: <div class="subsection">
1.30 cvs 4759: <h3><a name="sectc4222">Line breaking</a></h3>
1.1 cvs 4760:
1.30 cvs 4761: <p>The <tt>Line</tt> rule specifies that the contents of the box should be
4762: broken into lines: the boxes included in the box to which this rule is
4763: attached are displayed one after the other, from left to right, with their
4764: horizontal reference axes aligned so that they form a series of lines. The
4765: length of these lines is equal to the width of the box to which the
4766: <tt>Line</tt> rule is attached.</p>
4767:
4768: <p>When an included box overflows the current line, it is either carried
4769: forward to the next line, cur, or left the way it is. The <a
1.18 cvs 4770: href="#sectc4223"><tt>LineBreak</tt> rule</a> is used to allow or prevent the
1.1 cvs 4771: breaking of included boxes. If the included box is not breakable but is
4772: longer than the space remaining on the line, it is left as is. When a
4773: character string box is breakable, the line is broken between words or, if
1.18 cvs 4774: necessary, by <a href="#sectd42225">hyphenating a word</a>. When a compound
4775: box is breakable, the box is transparent in regard to line breaking. The boxes
4776: included in the compound box are treated just like included boxes which have
4777: the <tt>LineBreak</tt> rule. Thus, it is possible to traverse a complete
4778: subtree of boxes to line break the text leaves of a complex structure.</p>
1.30 cvs 4779:
4780: <p>The relative position rules of the included boxes are ignored, since the
4781: boxes will be placed according to the line breaking rules.</p>
4782:
4783: <p>The <tt>Line</tt> rule does not have a parameter. The characteristics of
4784: the lines that will be constructed are determined by the <tt>LineSpacing</tt>,
1.18 cvs 4785: <tt>Indent</tt>, <tt>Adjust</tt>, <tt>Justify</tt>, and <tt>Hyphenate</tt>
4786: rules. Moreover, the <a href="#insectd42226"><tt>Inline</tt> rule</a> permits
4787: the exclusion of certain elements from the line breaking process.</p>
1.30 cvs 4788:
4789: <p>When the <tt>Line</tt> rule appears in the rules sequence of a non-primary
1.18 cvs 4790: view, it applies only to that view, but when the <tt>Line</tt> rule appears in
1.1 cvs 4791: the rules sequence of the primary view, it also applies to the other views by
1.18 cvs 4792: default, except for those views which explicitly invoke the <tt>NoLine</tt>
4793: rule. Thus, the <tt>NoLine</tt> rule can be used in a non-primary view to
4794: override the primary view's <tt>Line</tt> rule. The <tt>NoLine</tt> rule must
4795: not be used with the primary view because the absence of the <tt>Line</tt>
4796: rule has the same effect. Like the <tt>Line</tt> rule, the <tt>NoLine</tt>
4797: rule does not take any parameters.</p>
4798: <pre> 'Line'
4799: 'NoLine'</pre>
4800:
4801: <div class="subsubsection">
1.30 cvs 4802: <h4><a name="sectd42221">Line spacing</a></h4>
1.18 cvs 4803:
1.30 cvs 4804: <p>The <tt>LineSpacing</tt> rule defines the line spacing to be used in the
4805: line breaking process. The line spacing is the distance between the baselines
1.1 cvs 4806: (horizontal reference axis) of the successive lines produced by the
1.18 cvs 4807: <tt>Line</tt> rule. The value of the line spacing can be specified as a
4808: constant or by inheritance. It is expressed in any of the available <a
4809: href="#sectc4217">distance units</a>.</p>
1.30 cvs 4810:
4811: <p>Inheritance allows the value to be obtained from a relative in the
4812: structure tree, either without change (an equals sign appears after the
4813: inheritance keyword), with a positive difference (a plus sign), or a negative
4814: difference (a minus sign). When the rule uses a difference, the value of the
4815: difference follows the sign and is expressed as a <a
4816: href="#sectc4217">distance</a>.</p>
1.18 cvs 4817: <pre> 'LineSpacing' ':' DistOrInherit
1.6 cvs 4818: DistOrInherit = Kinship InheritedDist / Distance .
1.18 cvs 4819: InheritedDist = '=' / '+' AbsDist / '-' AbsDist .</pre>
1.30 cvs 4820:
4821: <p>When the line spacing value (or its difference from another element) is
1.1 cvs 4822: expressed in relative units, it changes with the size of the characters. Thus,
4823: when a larger font is chosen for a part of the document, the line spacing of
4824: that part expands proportionally. In contrast, when the line spacing value is
4825: expressed in absolute units (centimeters, inches, typographer's points), it is
4826: independent of the characters, which permits the maintenance of a consistent
4827: line spacing, whatever the character font. Either approach can be taken,
1.18 cvs 4828: depending on the desired effect.</p>
4829: </div>
1.1 cvs 4830:
1.18 cvs 4831: <div class="subsubsection">
1.30 cvs 4832: <h4><a name="sectd42222">First line indentation</a></h4>
1.1 cvs 4833:
1.30 cvs 4834: <p>The <tt>Indent</tt> rule is used to specify the indentation of the first
4835: line of the elements broken into lines by the <tt>Line</tt> function. The
1.1 cvs 4836: indentation determines how far the first line of the element is shifted with
4837: respect to the other lines of the same element. It can be specified as a
4838: constant or by inheritance. The constant value is a positive integer (shifted
4839: to the right; the sign is optional), a negative integer (shifted to the left)
1.18 cvs 4840: or zero (no shift). All available <a href="#sectc4217">units</a> can be
4841: used.</p>
1.30 cvs 4842:
4843: <p>Indentation can be defined for any box, regardless of whether the box is
4844: line broken, and transmitted by inheritance to elements that are line broken.
4845: The size of the indentation is specified in the same manner as the <a
1.18 cvs 4846: href="#sectd42221">line spacing</a>.</p>
4847: <pre> 'Indent' ':' DistOrInherit</pre>
4848: </div>
1.1 cvs 4849:
1.18 cvs 4850: <div class="subsubsection">
1.30 cvs 4851: <h4><a name="sectd42223">Alignment</a></h4>
1.1 cvs 4852:
1.30 cvs 4853: <p>The alignment style of the lines constructed during line breaking is
4854: defined by the <tt>Adjust</tt> rule. The alignment value can be a constant or
1.18 cvs 4855: inherited. A constant value is specified by a keyword:</p>
4856: <ul>
1.30 cvs 4857: <li><tt>Left</tt>: at the left edge,</li>
4858: <li><tt>Right</tt>: at the right edge,</li>
4859: <li><tt>VMiddle</tt>: centered</li>
4860: <li><tt>LeftWithDots</tt>: at the left edge with a dotted line filling out
4861: the last line up to the right edge of the line breaking box.</li>
1.18 cvs 4862: </ul>
1.30 cvs 4863:
4864: <p>An inherited value can only be the same as that of the reference box and is
1.18 cvs 4865: specified by a kinship keyword followed by an equals sign.</p>
4866: <pre> 'Adjust' ':' AlignOrInherit
1.1 cvs 4867: AlignOrInherit = Kinship '=' / Alignment .
4868: Alignment = 'Left' / 'Right' / 'VMiddle' /
1.18 cvs 4869: 'LeftWithDots' .</pre>
4870: </div>
1.1 cvs 4871:
1.18 cvs 4872: <div class="subsubsection">
1.30 cvs 4873: <h4><a name="sectd42224">Justification</a></h4>
1.1 cvs 4874:
1.30 cvs 4875: <p>The <tt>Justify</tt> rule indicates whether the lines contained in the box
4876: and produced by a <tt>Line</tt> rule should be extended horizontally to occupy
4877: the entire width of their enclosing box. The first and last lines are treated
1.1 cvs 4878: specially: the position of the beginning of the first line is fixed by the
1.18 cvs 4879: <tt>Indent</tt> rule and last line is not extended. The justification
1.34 ! cvs 4880: property defined by this rule takes a boolean value, which can be a constant
1.1 cvs 4881: or inherited. A constant boolean value is expressed by either the
1.18 cvs 4882: <tt>Yes</tt> or the <tt>No</tt> keyword. An inherited value can only be the
1.1 cvs 4883: same as that of the reference box and is specified by a kinship keyword
1.18 cvs 4884: followed by an equals sign.</p>
4885: <pre> 'Justify' ':' BoolInherit
1.1 cvs 4886: BoolInherit = Boolean / Kinship '=' .
1.18 cvs 4887: Boolean ='Yes' / 'No' .</pre>
1.30 cvs 4888:
1.34 ! cvs 4889: <p>When the lines are justified, the alignment property specified in the
1.18 cvs 4890: <tt>Adjust</tt> rule has no influence, other than on the last line produced.
1.1 cvs 4891: This occurs because, when the other are extended to the limits of the box, the
1.18 cvs 4892: alignment style is no longer perceptible.</p>
1.30 cvs 4893:
1.18 cvs 4894: <blockquote class="example">
1.30 cvs 4895: <p><strong>Example:</strong></p>
4896:
4897: <p>An important use of inheritance is to vary the characteristics of lines
4898: for an element type (for example, Paragraph) according to the enclosing
4899: environment (for example, Summary or Section), and thus obtain different
4900: line breaking styles for the same elements when they appear in different
4901: environments. The following rules specify that paragraphs inherit their
4902: alignment, justification, and line spacing:</p>
4903: <pre>Paragraph :
1.1 cvs 4904: BEGIN
4905: Justify : Enclosing = ;
4906: LineSpacing : Enclosing = ;
4907: Adjust : Enclosing =;
4908: Line;
1.18 cvs 4909: END;</pre>
1.30 cvs 4910:
4911: <p>If the alignment, justification, and line spacing of the Section and
4912: Summary elements is fixed:</p>
4913: <pre>Section :
1.1 cvs 4914: BEGIN
4915: Adjust : Left;
4916: Justify : Yes;
4917: LineSpacing : 1;
4918: END;
4919: Summary :
4920: BEGIN
4921: Adjust : VMiddle;
4922: Justify : No;
4923: LineSpacing : 1.3;
1.18 cvs 4924: END;</pre>
1.30 cvs 4925:
4926: <p>then the paragraphs appearing in sections are justified with a simple
4927: line spacing while those appearing in summaries are centered and not
4928: justified and have a larger line spacing. These are nevertheless the very
4929: same type of paragraph defined in the logical structure schema.</p>
1.18 cvs 4930: </blockquote>
4931: </div>
4932:
4933: <div class="subsubsection">
1.30 cvs 4934: <h4><a name="sectd42225">Hyphenation</a></h4>
1.18 cvs 4935:
1.30 cvs 4936: <p>The <tt>Hyphenate</tt> rule indicates whether or not words should be broken
4937: by hyphenation at the end of lines. It affects the lines produced by the
1.18 cvs 4938: <tt>Line</tt> rule and contained in the box carrying the <tt>Hyphenate</tt>
4939: rule.</p>
1.30 cvs 4940:
1.34 ! cvs 4941: <p>The hyphenation property takes a boolean value, which can be either
1.30 cvs 4942: constant or inherited. A constant boolean value is expressed by either the
1.18 cvs 4943: <tt>Yes</tt> or the <tt>No</tt> keyword. An inherited value can only be the
1.1 cvs 4944: same as that of the reference box and is specified by a kinship keyword
1.18 cvs 4945: followed by an equals sign.</p>
4946: <pre> 'Hyphenate' ':' BoolInherit
1.1 cvs 4947: BoolInherit = Boolean / Kinship '=' .
1.18 cvs 4948: Boolean = 'Yes' / 'No' .</pre>
4949: </div>
4950:
4951: <div class="subsubsection">
1.30 cvs 4952: <h4><a name="sectd42226">Avoiding line breaking</a></h4>
1.18 cvs 4953:
1.30 cvs 4954: <p>The <tt>InLine</tt> rule is used to specify that a box that would otherwise
1.18 cvs 4955: participate in line breaking asked for by the <tt>Line</tt> rule of an
1.1 cvs 4956: enclosing box, instead avoids the line breaking process and positions itself
1.18 cvs 4957: according to the <tt>HorizPos</tt> and <tt>VertPos</tt> rules that apply to
4958: it. When the <tt>InLine</tt> rule applies to a box which would not be line
4959: broken, it has no effect.</p>
1.30 cvs 4960:
4961: <p>The rule is expressed by the <tt>InLine</tt> keyword followed by a colon
4962: and the keyword <tt>Yes</tt>, if the box should participate in line breaking,
4963: or the keyword <tt>No</tt>, if it should not. This is the only form possible:
1.1 cvs 4964: this rule cannot be inherited. Moreover, it can only appear in the rules of
4965: the primary view and applies to all views defined in the presentation
1.18 cvs 4966: schema.</p>
4967: <pre> 'InLine' ':' Boolean .
4968: Boolean = 'Yes' / 'No' .</pre>
1.30 cvs 4969:
1.18 cvs 4970: <blockquote class="example">
1.30 cvs 4971: <p><strong>Example:</strong></p>
4972:
4973: <p>Suppose the structure schema defines a logical attribute called
4974: <tt>New</tt> which is used to identify the passages in a document which were
4975: recently modified. It would be nice to have the presentation schema make a
4976: bar appear in the left margin next to each passage having the <tt>New</tt>
4977: attribute. A new passage can be an entire element, such as a paragraph or
4978: section, or it can be some words in the middle of a paragraph. To produce
4979: the desired effect, the <tt>New</tt> attribute is given a creation rule
4980: which generates a <tt>VerticalBar</tt> presentation box.</p>
4981:
4982: <p>When the <tt>New</tt> attribute is attached to a character string which
4983: is inside a line broken element (inside a paragraph, for example), the bar
4984: is one of the elements which participates in line breaking and it is placed
4985: normally in the current line, at the end of the character string which has
4986: the attribute. To avoid this, the <tt>InLine</tt> rule is used in the
4987: following way:</p>
4988: <pre>BOXES
1.1 cvs 4989: VerticalBar:
4990: BEGIN
4991: Content: Graphics 'l';
4992: HorizPos: Left = Root . Left;
4993: VertPos: Top = Creator . Top;
4994: Height: Bottom = Creator . Bottom;
4995: Width: 1 pt;
4996: InLine: No;
4997: ...
4998: END;
4999: ...
5000: ATTRIBUTES
5001: Nouveau:
5002: BEGIN
5003: CreateAfter(VerticalBar);
1.18 cvs 5004: END;</pre>
5005: </blockquote>
5006: </div>
5007: </div>
1.1 cvs 5008:
1.18 cvs 5009: <div class="subsection">
1.30 cvs 5010: <h3><a name="sectc4223">Page breaking and line breaking conditions</a></h3>
1.1 cvs 5011:
1.30 cvs 5012: <p>Pages are constructed by the editor in accordance with the model specified
5013: by a <a href="#sectc4233"><tt>Page</tt> rule</a>. The page model describes
5014: only the composition of the pages but does not give any rules for breaking
1.18 cvs 5015: different element types across pages. Now, it is possible that certain
5016: elements must not be cut by page breaks, while others can be cut anywhere. The
5017: <tt>PageBreak</tt>, <tt>NoBreak1</tt>, and <tt>NoBreak2</tt> rules are used to
5018: specify the conditions under which each element type can be cut.</p>
1.30 cvs 5019:
5020: <p>The <tt>PageBreak</tt> rule is used to indicate whether or not the box can
5021: be cut during the construction of pages. If cutting is authorized, the box
5022: can be cut, with one part appearing at the bottom of a page and the other part
1.1 cvs 5023: appearing at the top of the next page. The rule is formed by the
1.18 cvs 5024: <tt>PageBreak</tt> keyword followed by a colon and a constant boolean value
5025: (<tt>Yes</tt> or <tt>No</tt>). This is the only form possible: this rule
1.1 cvs 5026: cannot be inherited. Moreover, it can only appear in the rules of the primary
1.18 cvs 5027: view and applies to all views defined in the presentation schema.</p>
1.30 cvs 5028:
5029: <p>Whether objects can be cut by line breaks can be controlled in a similar
5030: way using the <tt>LineBreak</tt> rule. This rule allows the specification of
1.1 cvs 5031: whether or not the box can be cut during the construction of lines. If
5032: cutting is authorized, the box can be cut, with one part appearing at the end
5033: of a line and the other part appearing at the beginning of the next line. The
1.18 cvs 5034: rule is formed by the <tt>LineBreak</tt> keyword followed by a colon and a
5035: constant boolean value (<tt>Yes</tt> or <tt>No</tt>). This is the only form
1.1 cvs 5036: possible: this rule cannot be inherited. Moreover, it can only appear in the
5037: rules of the primary view and applies to all views defined in the presentation
1.18 cvs 5038: schema.</p>
5039: <pre> 'PageBreak' ':' Boolean .
1.1 cvs 5040: 'LineBreak' ':' Boolean .
1.18 cvs 5041: Boolean = 'Yes' / 'No' .</pre>
1.30 cvs 5042:
5043: <p>When a box can be cut by a page break, it is possible that a page break
5044: will fall an inappropriate spot, creating, for example, a widow or orphan, or
1.1 cvs 5045: separating the title of a section from the first paragraph of the section. The
1.18 cvs 5046: <tt>NoBreak1</tt> and <tt>NoBreak2</tt> rules are used to avoid this. They
5047: specify that the box of the element to which they apply cannot be cut within a
5048: certain zone at the top (<tt>NoBreak1</tt> rule) or at the bottom
5049: (<tt>NoBreak2</tt> rule). These two rules specify the height of the zones in
5050: which page breaks are prohibited.</p>
1.30 cvs 5051:
5052: <p>The <tt>NoBreak1</tt> and <tt>NoBreak2</tt> rules give the height of the
5053: zone in which page breaking is prohibited. The height is given as a constant
5054: value using any of the <a href="#sectc4217">available units</a>, absolute or
1.18 cvs 5055: relative. The value may not be inherited.</p>
5056: <pre> 'NoBreak1' ':' AbsDist .
5057: 'NoBreak2' ':' AbsDist .</pre>
1.30 cvs 5058:
1.18 cvs 5059: <blockquote class="example">
1.30 cvs 5060: <p><strong>Example:</strong></p>
5061:
5062: <p>The following rules prevent widows and orphans in a paragraph:</p>
5063: <pre>Paragraph :
1.1 cvs 5064: BEGIN
5065: NoBreak1 : 2;
5066: NoBreak2 : 2;
1.18 cvs 5067: END;</pre>
1.30 cvs 5068:
5069: <p>This rule prevents a section title from becoming separated from the first
5070: paragraph of the section by prohibiting page breaks at the beginning of the
5071: section rule:</p>
5072: <pre>Section :
1.18 cvs 5073: NoBreak1 : 1.5 cm;</pre>
1.30 cvs 5074:
5075: <p>Finally, this rule prevents a figure from being page broken in any
5076: way:</p>
5077: <pre>Figure :
1.18 cvs 5078: PageBreak : No;</pre>
5079: </blockquote>
1.30 cvs 5080:
5081: <p>The Thot editor constructs the document images displayed on the screen
1.1 cvs 5082: dynamically. As the user moves in the document or makes the document scroll
5083: in a window, the editor constructs the image to be displayed in little bits,
5084: filling the gaps which are produced in the course of these operations. It
5085: stops filling in the image when an element reaches the edge of the window in
5086: which the gap appears. If the appearance of the document is complex, it is
5087: possible that the image in incomplete, even though the edge of the window was
5088: reached. For example, an element might need to be presented to the side of
5089: the last element displayed, but its image was not constructed. The user will
5090: not know whether the element is really absent or if its image has simply not
1.18 cvs 5091: been constructed.</p>
1.30 cvs 5092:
5093: <p>The <tt>Gather</tt> rule is used to remedy this problem. When the rule
1.18 cvs 5094: <tt>Gather : Yes;</tt> is associated with an element type, the image of such
5095: elements is constructed as a block by the editor: it is never split up.</p>
1.30 cvs 5096:
5097: <p>The <tt>Gather</tt> rule may not appear in the <a href="#sectc427">default
1.18 cvs 5098: rules</a>. Elements which do not have the <tt>Gather</tt> rule are considered
5099: susceptible to being split up during display. Thus, it is not necessary to
5100: use the <tt>Gather : No;</tt> form. This rule must be used prudently and only
5101: for those elements which truly need it. If used incorrectly, it can
5102: pointlessly increase the size of the image constructed by the editor and lead
5103: to excessive memory consumption by the editor.</p>
1.30 cvs 5104:
5105: <p>Like the <tt>PageBreak</tt> and <tt>LineBreak</tt> rules, the
5106: <tt>Gather</tt> rule can only appear in rules of the primary view and applies
5107: to all views defined in the presentation schema.</p>
1.18 cvs 5108: <pre> 'Gather' ':' Boolean .</pre>
5109: </div>
1.1 cvs 5110:
1.18 cvs 5111: <div class="subsection">
1.30 cvs 5112: <h3><a name="sectc4224">Visibility</a></h3>
1.1 cvs 5113:
1.34 ! cvs 5114: <p>The visibility property is used to control which elements should or should
1.1 cvs 5115: not be displayed, based on context. An element can have different
5116: visibilities in different views. If an element's visibility is zero for a
5117: view, that element is not displayed in that view and does not occupy any space
1.18 cvs 5118: (its extents are zero).</p>
1.30 cvs 5119:
5120: <p>Visibility takes non-negative integer values (positive or zero). If values
1.1 cvs 5121: greater than 1 are used, they allow the user to choose a degree of visibility
1.34 ! cvs 5122: and, thus, to see only those boxes whose visibility property exceeds a certain
! 5123: threshold. This gives the user control over the granularity of the displayed
! 5124: pictures.</p>
1.30 cvs 5125:
1.34 ! cvs 5126: <p>The visibility property can be defined as a constant or by inheritance. If
1.1 cvs 5127: defined by inheritance, it cannot be based on the value of the next or
1.18 cvs 5128: previous box. Visibility can only be inherited from above.</p>
1.30 cvs 5129:
5130: <p>If it is a numeric attribute's presentation rule, the visibility can be
1.1 cvs 5131: specified by the attribute's name, in which case the value of the attribute is
1.18 cvs 5132: used.</p>
5133: <pre> 'Visibility' ':' NumberInherit
1.1 cvs 5134: NumberInherit = Integer / AttrID / Inheritance .
1.18 cvs 5135: Integer = NUMBER .</pre>
1.30 cvs 5136:
1.18 cvs 5137: <blockquote class="example">
1.30 cvs 5138: <p><strong>Example:</strong></p>
5139:
5140: <p>Suppose that only <tt>Formula</tt> elements should be displayed in the
5141: <tt>MathView</tt> view. Then, the default rules should include:</p>
5142: <pre>DEFAULT
1.18 cvs 5143: IN MathView Visibility:0;</pre>
1.30 cvs 5144:
1.31 cvs 5145: <p>which makes all elements invisible in the <tt>MathView</tt> view.
1.30 cvs 5146: However, the <tt>Formula</tt> element also has a <tt>Visibility</tt>
5147: rule:</p>
5148: <pre>Formula :
1.18 cvs 5149: IN MathView Visibility:5;</pre>
1.30 cvs 5150:
5151: <p>which makes formulas, and only formulas, visible.</p>
1.18 cvs 5152: </blockquote>
5153: </div>
1.1 cvs 5154:
1.18 cvs 5155: <div class="subsection">
1.34 ! cvs 5156: <h3><a name="sectc4225">Character style properties</a></h3>
1.1 cvs 5157:
1.34 ! cvs 5158: <p>Four properties are used to determine which characters are used to display
1.18 cvs 5159: text. They are size, font, style, and underlining.</p>
1.1 cvs 5160:
1.18 cvs 5161: <div class="subsubsection">
1.30 cvs 5162: <h4><a name="sectd42251">Character size</a></h4>
5163:
1.34 ! cvs 5164: <p>The size property has two effects. First, it is used to specify the actual
! 5165: size and distance units for boxes defined in <a href="#sectc4217">relative
! 5166: units</a>. Second, it defines the size of the characters contained in the
! 5167: box.</p>
1.1 cvs 5168:
1.30 cvs 5169: <p>As a distance or length, the size can be expressed in abstract or absolute
1.1 cvs 5170: units. It can also be inherited. If it is not inherited, it is expressed
1.18 cvs 5171: simply as an integer followed by the <tt>pt</tt> keyword, which indicates that
5172: the size is expressed in typographer's points. The absence of the <tt>pt</tt>
1.1 cvs 5173: keyword indicates that it is in abstract units in which the value 1 represents
5174: the smallest size while the value 16 is the largest size. The relationship
5175: between these abstract sizes and the real character sizes is controlled by a
5176: table which can be modified statically or even dynamically during the
1.18 cvs 5177: execution of the Thot editor.</p>
1.30 cvs 5178:
5179: <p>If the <tt>Size</tt> rule is a numeric attribute's presentation rule, the
1.34 ! cvs 5180: value of the size property can be specified by the attribute's name, in which
1.30 cvs 5181: case the value of the attribute is used.</p>
5182:
5183: <p><strong>Note:</strong> the only unit available for defining an absolute
5184: size is the typographer's point. Centimeters and inches may not be used.</p>
5185:
5186: <p>If the size is inherited, the rule must specify the relative from which to
5187: inherit and any percentage or difference from that relative's value. A
5188: percentage is indicated by a <tt>*</tt> followed by the value of the
5189: percentage and a <tt>%</tt>. A difference can be expressed in either
5190: typographer's points or in abstract units and the maximum or minimum size can
5191: be specified, but without specifying the unit: it is the same as was specified
5192: for the difference.</p>
5193:
5194: <p>In a numeric attribute's presentation rule, the difference in size or the
1.22 cvs 5195: percentage can be indicated by the attribute's name instead of the numeric
5196: value, which means that the attribute's value should be used as the difference
5197: or percentage. The attribute can also be used as the minimum or maximum size
5198: for a difference.</p>
5199: <pre> 'Size' ':' SizeInherit
5200: SizeInherit = SizeAttr [ 'pt' ] /
5201: Kinship InheritedSize .
5202: InheritedSize ='+' SizeAttr [ 'pt' ]
5203: [ 'Max' MaxSizeAttr ] /
5204: '-' SizeAttr [ 'pt' ]
5205: [ 'Min' MinSizeAttr ] /
5206: '*' PercentSizeAttr '%' /
5207: '=' .
5208: SizeAttr = Size / AttrID .
5209: Size = NUMBER .
5210: MaxSizeAttr = MaxSize / AttrID .
5211: MaxSize = NUMBER .
5212: MinSizeAttr = MinSize / AttrID .
5213: MinSize = NUMBER .
5214: PercentSizeAttr = PercentSize / AttrID .
5215: PercentSize = NUMBER .</pre>
1.30 cvs 5216:
1.18 cvs 5217: <blockquote class="example">
1.30 cvs 5218: <p><strong>Example:</strong></p>
5219:
5220: <p>The rule</p>
5221: <pre>Size : Enclosing - 2 pt Min 7;</pre>
5222:
5223: <p>states that the character size is 2 points less than that of the
5224: enclosing box, but that it may not be less than 7 points, whatever the
5225: enclosing box's value.</p>
5226:
5227: <p>The following rules make the text of a report be displayed with
5228: medium-sized characters (for example, size 5), while the title is displayed
5229: with larger characters and the summary is displayed with smaller
5230: characters:</p>
5231: <pre>Report :
1.1 cvs 5232: Size : 5;
5233: Title :
5234: Size : Enclosing + 2;
5235: Summary :
1.18 cvs 5236: Size : Enclosing - 1;</pre>
1.30 cvs 5237:
5238: <p>Thus, the character sizes in the entire document can be changed by
1.34 ! cvs 5239: changing the size property of the Report element, while preserving the
1.30 cvs 5240: relationships between the sizes of the different elements.</p>
1.18 cvs 5241: </blockquote>
5242: </div>
5243:
5244: <div class="subsubsection">
1.30 cvs 5245: <h4><a name="sectd42252">Font and character style</a></h4>
1.18 cvs 5246:
1.30 cvs 5247: <p>The <tt>Font</tt> rule determines the font family to be used to display the
1.18 cvs 5248: characters contained in the box, while the <tt>Style</tt> rule determines
1.23 cvs 5249: their style and the <tt>Weight</tt> rule determines their weight. Thot
5250: recognizes three character fonts (Times, Helvetica, and Courier), three
5251: styles: Roman, Italics, and Oblique, and two weights: Normal and Bold.</p>
1.30 cvs 5252:
5253: <p>The font family, style and weight can be specified by a named constant or
5254: can be inherited. For the name of the font family only the first character is
5255: used.</p>
5256:
5257: <p>Only identical inheritance is allowed: the box takes the same font, style
5258: or weight as the box from which it inherits. This is indicated by an equals
1.23 cvs 5259: sign after the kinship specification.</p>
5260: <pre> 'Font' ':' NameInherit /
5261: 'Style' ':' StyleInherit /
5262: 'Weight' ':' WeightInherit /
5263:
5264: NameInherit = Kinship '=' / FontName .
5265: FontName = NAME .
5266: StyleInherit = Kinship '=' /
5267: 'Roman' / 'Italics' / 'Oblique' .
5268: WeightInherit = Kinship '=' /
5269: 'Normal' / 'Bold' .</pre>
1.30 cvs 5270:
1.18 cvs 5271: <blockquote class="example">
1.30 cvs 5272: <p><strong>Example:</strong></p>
5273:
5274: <p>To specify that the summary uses the font family of the rest of the
5275: document, but in the italic style, the following rules are used:</p>
5276: <pre>Summary :
1.1 cvs 5277: BEGIN
5278: Font : Enclosing =;
5279: Style : Italics;
1.18 cvs 5280: END;</pre>
5281: </blockquote>
5282: </div>
5283:
5284: <div class="subsubsection">
1.30 cvs 5285: <h4><a name="sectd42253">Underlining</a></h4>
1.18 cvs 5286:
1.30 cvs 5287: <p>The <tt>Underline</tt> rule is used to specify if the characters contained
5288: in a box should have lines drawn on or near them. There are four underlining
1.18 cvs 5289: styles: <tt>Underlined</tt>, <tt>Overlined</tt>, <tt>CrossedOut</tt>, and
5290: <tt>NoUnderline</tt>. The <tt>Thickness</tt> rule specifies the thickness of
5291: the line, <tt>Thin</tt> or <tt>Thick</tt>.</p>
1.30 cvs 5292:
5293: <p>As with font family and style, only identical inheritance is allowed: the
5294: box has the same underlining type as the box from which it inherits the value.
1.18 cvs 5295: This is indicated by an equals sign after the kinship specification.</p>
5296: <pre> 'Underline' ':' UnderLineInherit /
1.1 cvs 5297: 'Thickness' ':' ThicknessInherit /
5298:
5299: UnderLineInherit = Kinship '=' / 'NoUnderline' /
5300: 'Underlined' /
5301: 'Overlined' / 'CrossedOut' .
1.18 cvs 5302: ThicknessInherit = Kinship '=' / 'Thick' / 'Thin' .</pre>
5303: </div>
5304: </div>
5305:
5306: <div class="subsection">
1.30 cvs 5307: <h3><a name="sectc4226">Stacking order</a></h3>
1.18 cvs 5308:
1.30 cvs 5309: <p>The <tt>Depth</tt> rule is used to define the stacking order of terminal
5310: boxes when multiple boxes at least partially overlap. This rule defines how
1.34 ! cvs 5311: the depth property, which is zero or a positive integer, is calculated. The
! 5312: depth property has a value for all boxes. For terminal boxes in the structure
! 5313: and for presentation boxes, the depth value is used during display and
! 5314: printing: the boxes with the lowest value overlap those with higher depths.
! 5315: For non-terminal boxes, the depth is not interpreted during display, but it is
! 5316: used to calculate the depth of terminal boxes by inheritance.</p>
1.30 cvs 5317:
5318: <p>Like most other rules, the depth rule is defined in the <a
1.18 cvs 5319: href="#sectc427">default rules</a> of each presentation schema. Thus, there
5320: is always a depth value, even when it is not necessary because there is no
5321: overlapping. To avoid useless operations, a zero value can be given to the
1.34 ! cvs 5322: depth property, which signifies that overlapping is never a problem.</p>
1.30 cvs 5323:
5324: <p>The depth rule has the same form as the <a href="#sectc4224">visibility
1.18 cvs 5325: rule</a>. It can be defined by inheritance or by a constant numeric value.
5326: When the rule is attached to a numeric attribute, it can take the value of
5327: that attribute.</p>
5328: <pre> 'Depth' ':' NumberInherit</pre>
1.30 cvs 5329:
1.18 cvs 5330: <blockquote class="example">
1.30 cvs 5331: <p><strong>Example:</strong></p>
5332:
5333: <p>For a purely textual document, in which overlapping never poses a
5334: problem, a single default <tt>Depth</tt> rule in the presentation schema is
5335: sufficient:</p>
5336: <pre>DEFAULT
1.1 cvs 5337: Depth : 0;
1.18 cvs 5338: ...</pre>
1.30 cvs 5339:
5340: <p>To make the text of examples appear on a light blue background, a
5341: presentation box is defined:</p>
5342: <pre>BOXES
1.1 cvs 5343: BlueBG :
5344: BEGIN
5345: Content : Graphics 'R';
5346: Background : LightBlue3;
5347: FillPattern: backgroundcolor;
5348: Depth : 2;
5349: ...
1.18 cvs 5350: END;</pre>
1.30 cvs 5351:
5352: <p>and is created by the <tt>Example</tt> element, which has the rules:</p>
5353: <pre>RULES
1.1 cvs 5354: Example :
5355: BEGIN
5356: CreateFirst (BlueBG);
5357: Depth : 1;
5358: ...
1.18 cvs 5359: END;</pre>
1.30 cvs 5360:
5361: <p>In this way, the text of an example (if it inherits its depth from its
5362: ancestor) will be superimposed on a light blue background, and not the
5363: reverse).</p>
1.18 cvs 5364: </blockquote>
5365: </div>
5366:
5367: <div class="subsection">
1.30 cvs 5368: <h3><a name="sectc4227">Line style</a></h3>
1.18 cvs 5369:
1.30 cvs 5370: <p>The <tt>LineStyle</tt> rule determines the style of line which should be
5371: used to draw all the elements contained in the box and the box itself, if it
5372: has a <a href="#sectc4230a"><tt>ShowBox</tt> rule</a>. The line style can be
1.18 cvs 5373: indicated by a name (<tt>Solid</tt>, <tt>Dashed</tt>, <tt>Dotted</tt>) or it
1.13 cvs 5374: can be inherited. All elements of the graphic base type are affected by this
1.1 cvs 5375: rule, but it can be attached to any box and transmitted by inheritance to the
1.18 cvs 5376: graphic elements. The border of elements having a <a
5377: href="#sectc4230a"><tt>ShowBox</tt> rule</a> is drawn according to the line
5378: style specified by this rule.</p>
1.30 cvs 5379:
5380: <p>Only identical inheritance is allowed: the box takes the same line style as
1.1 cvs 5381: the box from which it inherits. This is indicated by an equals sign after the
1.18 cvs 5382: kinship specification.</p>
5383: <pre> 'LineStyle' ':' LineStyleInherit
1.1 cvs 5384: LineStyleInherit = Kinship '=' /
1.18 cvs 5385: 'Solid' / 'Dashed' / 'Dotted' .</pre>
1.30 cvs 5386:
1.18 cvs 5387: <blockquote class="example">
1.30 cvs 5388: <p><strong>Example:</strong></p>
5389:
5390: <p>To specify that, in Figures, the graphical parts should be drawn in solid
5391: lines, the Figure element is given a rule using the <tt>Solid</tt> name:</p>
5392: <pre>Figure :
1.18 cvs 5393: LineStyle : Solid;</pre>
1.30 cvs 5394:
5395: <p>and the elements composing figures are given an inheritance rule:</p>
5396: <pre> LineStyle : Enclosing =;</pre>
1.18 cvs 5397: </blockquote>
5398: </div>
5399:
5400: <div class="subsection">
1.30 cvs 5401: <h3><a name="sectc4228">Line thickness</a></h3>
1.18 cvs 5402:
1.30 cvs 5403: <p>The <tt>LineWeight</tt> rule determines the thickness of the lines of all
1.1 cvs 5404: graphical elements which appear in the box, no matter what their line style.
5405: Line thickness can be specified by a constant value or by inheritance. A
5406: constant value is a positive number followed by an optional unit specification
1.18 cvs 5407: (which is absent when using relative units). All available <a
5408: href="#sectc4217">distance units</a> can be used. Line thickness is expressed
5409: in the same way as <a href="#sectd42221">line spacing</a>.</p>
5410: <pre> 'LineWeight' ':' DistOrInherit</pre>
1.30 cvs 5411:
5412: <p>All elements of the graphic base type are affected by this rule, but it can
5413: be attached to any box and transmitted by inheritance to the graphic elements.
1.18 cvs 5414: The border of element having a <a href="#sectc4230a"><tt>ShowBox</tt> rule</a>
5415: is also drawn according to the thickness specified by this rule.</p>
1.30 cvs 5416:
1.18 cvs 5417: <blockquote class="example">
1.30 cvs 5418: <p><strong>Example:</strong></p>
5419:
5420: <p>To specify that, in Figures, the graphical parts should be drawn with
5421: lines 0.3 pt thick, the Figure element is given this rule:</p>
5422: <pre>Figure :
1.18 cvs 5423: LineWeight : 0.3 pt;</pre>
1.30 cvs 5424:
5425: <p>and the elements composing figures are given an inheritance rule:</p>
5426: <pre> LineWeight : Enclosing =;</pre>
1.18 cvs 5427: </blockquote>
5428: </div>
5429:
5430: <div class="subsection">
1.30 cvs 5431: <h3><a name="sectc4229">Fill pattern</a></h3>
1.18 cvs 5432:
1.30 cvs 5433: <p>The <tt>FillPattern</tt> rule determines the pattern used to fill closed
1.1 cvs 5434: graphical elements (circles, rectangles, etc.) which appear in the box. This
1.18 cvs 5435: rule also specifies the pattern used to fill the box associated with elements
5436: having a <a href="#sectc4230a"><tt>ShowBox</tt> rule</a><a>. This pattern can
5437: be indicated by a named constant or by inheritance. The named constant
5438: identifies one of the patterns available in Thot. The names of the available
5439: patterns are: nopattern, foregroundcolor, backgroundcolor, gray1, gray2,
5440: gray3, gray4, gray5, gray6, gray7, horiz1, horiz2, horiz3, vert1, vert2,
5441: vert3, left1, left2, left3, right1, right2, right3, square1, square2, square3,
5442: lozenge, brick, tile, sea, basket.</a></p>
1.30 cvs 5443:
5444: <p>Like the other rules peculiar to graphics, <tt>LineStyle</tt> and
1.18 cvs 5445: <tt>LineWeight</tt>, only elements of the graphic base type are affected by
5446: the <tt>FillPattern</tt> rule, but the rule can be attached to any box and
1.1 cvs 5447: transmitted by inheritance to the graphic elements. As with the other rules
1.18 cvs 5448: specific to graphics, only identical inheritance is allowed.</p>
1.30 cvs 5449:
5450: <p>The <tt>FillPattern</tt> rule can also be used to determine whether or not
1.12 cvs 5451: text characters, symbols and pictures should be colored. For these element
5452: types (text, symbols, and pictures), the only valid values are
1.18 cvs 5453: <tt>nopattern</tt>, <tt>foregroundcolor</tt>, and <tt>backgroundcolor</tt>.
5454: When <tt>FillPattern</tt> has the value <tt>backgroundcolor</tt>, text
5455: characters, symbols, and bitmaps are given the color specified by the <a
5456: href="#sectc4230"><tt>Background</tt> rule</a> which applies to these
5457: elements. When <tt>FillPattern</tt> has the value <tt>foregroundcolor</tt>,
5458: these same elements are given the color specified by the <a
5459: href="#sectc4230"><tt>Foreground</tt> rule</a> which applies to these
5460: elements. In all other case, text characters are not colored.</p>
5461: <pre> 'FillPattern' ':' NameInherit</pre>
1.30 cvs 5462:
1.18 cvs 5463: <blockquote class="example">
1.30 cvs 5464: <p><strong>Example:</strong></p>
5465:
5466: <p>To specify that, in Figures, the closed graphical elements should be
5467: filled with a pattern resembling a brick wall, the Figure element is given
5468: this rule:</p>
5469: <pre>Figure :
1.18 cvs 5470: FillPattern : brick;</pre>
1.30 cvs 5471:
5472: <p>and the elements composing figures are given an inheritance rule:</p>
5473: <pre> FillPattern : Enclosing =;</pre>
1.18 cvs 5474: </blockquote>
5475: </div>
5476:
5477: <div class="subsection">
1.30 cvs 5478: <h3><a name="sectc4230">Colors</a></h3>
1.18 cvs 5479:
1.30 cvs 5480: <p>The <tt>Foreground</tt> and <tt>Background</tt> rules determine the
5481: foreground and background colors of the base elements which appear in the box.
5482: They also control the color of boxes associated with elements having a <a
1.18 cvs 5483: href="#sectc4230a"><tt>ShowBox</tt> rule</a>. These colors can be specified
5484: with a named constant or by inheritance. The named constants specify one of
5485: the available colors in Thot. The available color names can be found in the
1.30 cvs 5486: file <tt>thot.color</tt>. In addition to those names, you can use the keyword
5487: <code>Transparent</code>, to not draw anything.</p>
5488:
5489: <p>The color rules affect the same way all base elements and elements having a
5490: <a href="#sectc4230a"><tt>ShowBox</tt> rule</a>, no matter what their type
5491: (text, graphics, pictures, symbols). The color rules can be associated with
5492: any box and can be transmitted by inheritance to the base elements or the
5493: elements having a <a href="#sectc4230a"><tt>ShowBox</tt> rule</a>. Like the
5494: preceding rules, only inheritance of the same value is allowed.</p>
5495: <pre> 'Foreground' ':' Color
5496: 'Background' ':' Color
5497: Color = 'Transparent' / Link '=' / FontColorName .</pre>
5498:
5499: <p><strong>Note:</strong> text colors only appear for text elements whose <a
1.18 cvs 5500: href="#sectc4229">fill pattern</a> does not prevent the use of color.</p>
1.30 cvs 5501:
1.18 cvs 5502: <blockquote class="example">
1.30 cvs 5503: <p><strong>Example:</strong></p>
5504:
5505: <p>To specify that, in Figures, everything must be drawn in blue on a
5506: background of yellow, the Figure element is given these rules:</p>
5507: <pre>Figure :
1.1 cvs 5508: BEGIN
5509: Foreground : Blue;
5510: Background : Yellow;
5511: Fillpattern : backgroundcolor;
1.18 cvs 5512: END;</pre>
1.30 cvs 5513:
5514: <p>and the elements composing figures are given inheritance rules:</p>
5515: <pre> Foreground : Enclosing =;
1.1 cvs 5516: Background : Enclosing =;
1.18 cvs 5517: FillPattern : Enclosing =;</pre>
5518: </blockquote>
5519: </div>
5520:
5521: <div class="subsection">
1.30 cvs 5522: <h3><a name="sectc4230a">Background color and border</a></h3>
1.18 cvs 5523:
1.30 cvs 5524: <p>Boxes associated with structural elements are normally not visible, but it
5525: is possible to draw their border and/or to paint their area when it is needed.
1.18 cvs 5526: This is achieved by associating the <tt>ShowBox</tt> rule with the concerned
1.13 cvs 5527: element. This rule has no parameter and no value. It is simply written
1.18 cvs 5528: <tt>Showbox;</tt>. It is not inherited nor transmitted to any other element.
5529: It applies only to the element with which it is associated.</p>
5530: <pre> 'ShowBox'</pre>
1.30 cvs 5531:
5532: <p>When an element has a <tt>ShowBox</tt> rule, the border is drawn only if
5533: the <tt>LineWeight</tt> rule that applies to that element has a non-zero value
1.18 cvs 5534: (this value can be inherited). The color, style and thickness of the border
5535: are defined by the <tt>Foreground</tt>, <tt>LineStyle</tt>, and
5536: <tt>LineWeight</tt> rules that apply to the element.</p>
1.30 cvs 5537:
5538: <p>When an element has a <tt>ShowBox</tt> rule, the background of this element
5539: is paint only if the value of the <tt>FillPattern</tt> rule that applies to
5540: that element is not <tt>nopattern</tt>. The pattern and color(s) of the
5541: background are defined by the <tt>FillPattern</tt>, <tt>Background</tt>, and
1.18 cvs 5542: <tt>Foreground</tt> rules that apply to the element.</p>
5543: </div>
5544:
5545: <div class="subsection">
1.30 cvs 5546: <h3><a name="sectc4230b">Background pictures</a></h3>
1.18 cvs 5547:
1.30 cvs 5548: <p>The <tt>BackgroundPicture</tt> rule allows to display a picture as the
1.13 cvs 5549: background of an element. It has a single parameter, the file name of the
1.18 cvs 5550: picture. This is a string delimited by single quotes. If the first character
5551: in this string is '/', it is considered as an absolute path, otherwise the
5552: file is searched for along the schema directory path. This file may contain a
5553: picture in any format accepted by Thot (xbm, xpm, gif, jpeg, png, etc.)</p>
1.30 cvs 5554:
5555: <p>The <tt>BackgroundPicture</tt> and <tt>PictureMode</tt> rules apply only to
1.13 cvs 5556: the element with which they are associated. They are not inherited nor
1.18 cvs 5557: transmitted to children elements.</p>
1.30 cvs 5558:
5559: <p>The background picture has not always the same size as the element's box.
1.13 cvs 5560: There are diffrent ways to fill the element box with the picture. This is
1.18 cvs 5561: specified by the <tt>PictureMode</tt> rule, which should be associated to the
5562: same element. This rule may take one of the following values:</p>
5563: <dl>
1.30 cvs 5564: <dt><tt>NormalSize</tt></dt>
5565: <dd>The picture is centered in the box, and clipped if it is too
5566: large.</dd>
5567: <dt><tt>Scale</tt></dt>
5568: <dd>The picture is zoomed to fit the box size.</dd>
5569: <dt><tt>RepeatX</tt></dt>
5570: <dd>The picture is repeated horizontally to fit the box width.</dd>
5571: <dt><tt>RepeatY</tt></dt>
5572: <dd>The picture is repeated vertically to fit the box height.</dd>
5573: <dt><tt>RepeatXY</tt></dt>
5574: <dd>The picture is repeated both horizontally and vertically to fill the
5575: box.</dd>
1.18 cvs 5576: </dl>
1.30 cvs 5577:
5578: <p>If an element has a <tt>BackgroundPicture</tt> rule and no
1.18 cvs 5579: <tt>PictureMode</tt> rule, the <tt>NormalSize</tt> value is assumed.</p>
5580: <pre> 'BackgroundPicture' ':' FileName /
1.13 cvs 5581: 'PictureMode' ':' PictMode .
5582:
5583: FileName = STRING .
1.18 cvs 5584: PictMode = 'NormalSize' / 'Scale' / 'RepeatXY' / 'RepeatX' / 'RepeatY' .</pre>
1.30 cvs 5585:
5586: <p>The <tt>BackgroundPicture</tt> and <tt>PictureMode</tt> rules apply only to
1.13 cvs 5587: the element with which they are associated. They are not inherited nor
1.18 cvs 5588: transmitted to children elements.</p>
5589: </div>
1.13 cvs 5590:
1.18 cvs 5591: <div class="subsection">
1.30 cvs 5592: <h3><a name="sectc4231">Presentation box content</a></h3>
1.1 cvs 5593:
1.30 cvs 5594: <p>The <tt>Content</tt> rule applies to presentation boxes. It indicates the
1.1 cvs 5595: content given to a box. This content is either a variable's value or a
1.18 cvs 5596: constant value. In the special case of <a href="#sectc4233">header or footer
5597: boxes</a>, the content can also be a structured element type.</p>
1.30 cvs 5598:
5599: <p>If the content is a constant, it can be specified, as in a variable
1.18 cvs 5600: declaration, either by the name of a constant declared in the <tt>CONST</tt>
1.1 cvs 5601: section or by direct specification of the type and value of the box's
1.18 cvs 5602: content.</p>
1.30 cvs 5603:
5604: <p>Similarly, if it is a variable, the name of a variable declared in
1.18 cvs 5605: <tt>VAR</tt> section can be given or the variable may be defined within
5606: parentheses. The content inside the parentheses has the same syntax as a <a
5607: href="#sectc426">variable declaration</a>.</p>
1.30 cvs 5608:
5609: <p>When the content is a structured element type, the name of the element type
5610: is given after the colon. In this case, the box's content is all elements of
1.1 cvs 5611: the named type which are designated by references which are part of the page
1.18 cvs 5612: on which the header or footer with this <tt>Content</tt> rule appears. Only
5613: associated elements can appear in a <tt>Content</tt> rule and the structure
1.1 cvs 5614: must provide references to these elements. Moreover, the box whose content
5615: they are must be a header or footer box generated by a page box of the primary
1.18 cvs 5616: view.</p>
5617: <pre> 'Content' ':' VarConst
1.1 cvs 5618: VarConst = ConstID / ConstType ConstValue /
5619: VarID / '(' FunctionSeq ')' /
1.18 cvs 5620: ElemID .</pre>
1.30 cvs 5621:
5622: <p>A presentation box can have only one <tt>Content</tt> rule, which means
5623: that the content of a presentation box cannot vary from view to view. However,
5624: such an effect can be achieved by creating several presentation boxes, each
5625: with different content and visible in different views.</p>
5626:
5627: <p>The <tt>Content</tt> rule also applies to elements defined as references in
1.1 cvs 5628: the structure schema. In this case, the content defined by the rule must be
5629: a constant. It is this content which appears on the screen or paper to
5630: represent references of the type to which the rule applies. A reference can
1.18 cvs 5631: have a <tt>Content</tt> rule or a <a href="#sectc4234"><tt>Copy</tt> rule</a>
1.1 cvs 5632: for each view. If neither of these rules appears, the reference is displayed
1.18 cvs 5633: as <tt>[*]</tt>, which is equivalent to the rule:</p>
5634: <pre> Content: Text '[*]';</pre>
1.30 cvs 5635:
1.18 cvs 5636: <blockquote class="example">
1.30 cvs 5637: <p><strong>Example:</strong></p>
5638:
5639: <p>The content of the presentation box created to make the chapter number
5640: and section number appear before each section title can be defined by:</p>
5641: <pre>BOXES
1.1 cvs 5642: SectionNumBox :
5643: BEGIN
5644: Content : NumSection;
5645: ...
1.18 cvs 5646: END;</pre>
1.30 cvs 5647:
5648: <p>if the <tt>NumSection</tt> variable has been defined in the variable
5649: definition section of the presentation schema. Otherwise the
5650: <tt>Content</tt> would be written:</p>
5651: <pre>BOXES
1.1 cvs 5652: SectionNumBox :
5653: BEGIN
5654: Content : (VALUE (ChapterCtr, Roman) TEXT '.'
5655: VALUE (SectionCtr, Arabic));
5656: ...
1.18 cvs 5657: END;</pre>
1.30 cvs 5658:
5659: <p>To specify that a page footer should contain all elements of the
5660: <tt>Note</tt> type are referred to in the page, the following rule is
5661: written:</p>
5662: <pre>BOXES
1.1 cvs 5663: NotesFooterBox :
5664: BEGIN
5665: Content : Note;
5666: ...
1.18 cvs 5667: END;</pre>
1.30 cvs 5668:
5669: <p><tt>Note</tt> is defined as an associated element in the structure schema
5670: and NotesFooterBox is created by a page box of the primary view.</p>
1.18 cvs 5671: </blockquote>
5672: </div>
1.1 cvs 5673:
1.18 cvs 5674: <div class="subsection">
1.30 cvs 5675: <h3><a name="sectc4232">Presentation box creation</a></h3>
1.1 cvs 5676:
1.30 cvs 5677: <p>A creation rule specifies that a presentation box should be created when an
1.18 cvs 5678: element of the type to which the rule is attached appears in the document.</p>
1.30 cvs 5679:
5680: <p>A keyword specifies the position, relative to the creating box, at which
5681: the created box will be placed in the structure:</p>
1.18 cvs 5682: <dl>
1.30 cvs 5683: <dt><tt>CreateFirst</tt></dt>
5684: <dd>specifies that the box should be created as the first box of the next
5685: lower level, before any already existing boxes, and only if the
5686: beginning of the creating element is visible;</dd>
5687: <dt><tt>CreateLast</tt></dt>
5688: <dd>specifies that the box should be created as the last box of the next
5689: lower level, after any existing boxes, and only if the end of the
5690: creating element is visible;</dd>
5691: <dt><tt>CreateBefore</tt></dt>
5692: <dd>specifies that the box should be created before the creating box, on
5693: the same level as the creating box, and only if the beginning of the
5694: creating element is visible;</dd>
5695: <dt><tt>CreateAfter</tt></dt>
5696: <dd>specifies that the box should be created after the creating box, on
5697: the same level as the creating box, and only if the beginning of the
5698: creating element is visible;</dd>
5699: <dt><tt>CreateEnclosing</tt></dt>
5700: <dd>specifies that the box should be created at the upper level relatively
5701: to the creating box, and that it must contain that creating box and all
5702: presentation boxes created by the same creating box.</dd>
1.18 cvs 5703: </dl>
1.30 cvs 5704:
5705: <p>This keyword can be followed by the <tt>Repeated</tt> keyword to indicate
5706: that the box must be created for each part of the creating element. These
5707: parts result from the division of the element by page breaks or column
5708: changes. If the <tt>Repeated</tt> keyword is missing, the box is only created
5709: for the first part of the creating element (<tt>CreateFirst</tt> and
1.18 cvs 5710: <tt>CreateBefore</tt> rules) or for the last part (<tt>CreateLast</tt> and
5711: <tt>CreateAfter</tt> rules).</p>
1.30 cvs 5712:
5713: <p>The type of presentation to be created is specified at the end of the rule
1.18 cvs 5714: between parentheses.</p>
1.30 cvs 5715:
5716: <p>Creation rules cannot appear in the <a href="#sectc427">default
5717: presentation rules</a>. The boxes being created should have a
5718: <tt>Content</tt> rule which indicates their <a
5719: href="#sectc4231">content</a>.</p>
5720:
5721: <p>Creation rules can only appear in the block of rules for the primary view;
1.1 cvs 5722: creation is provoked by a document element for all views. However, for each
5723: view, the presentation box is only created if the creating element is itself a
1.34 ! cvs 5724: box in the view. Moreover, the visibility property of the presentation box can
! 5725: be adjusted to control the creation of the box on a view-by-view basis.</p>
1.18 cvs 5726: <pre> Creation '(' BoxID ')'
1.1 cvs 5727: Creation = Create [ 'Repeated' ] .
5728: Create ='CreateFirst' / 'CreateLast' /
5729: 'CreateBefore' / 'CreateAfter' /
1.18 cvs 5730: 'CreateEnclosing' .</pre>
1.30 cvs 5731:
1.18 cvs 5732: <blockquote class="example">
1.30 cvs 5733: <p><strong>Example:</strong></p>
5734:
5735: <p>Let us define an object type, called Table, which is composed of a
5736: sequence of columns, all having the same fixed width, where the columns are
5737: separated by vertical lines. There is a line to the left of the first
5738: column and one to the right of the last. Each column has a variable number
1.31 cvs 5739: of cells, placed one on top of the other and separated by horizontal lines.
5740: There are no horizontal lines above the first cell or below the last cell.
1.30 cvs 5741: The text contained in each cell is broken into lines and these lines are
5742: centered horizontally in the cell. The logical structure of this object is
5743: defined by:</p>
5744: <pre>Table = LIST OF (Column);
1.18 cvs 5745: Column = LIST OF (Cell = Text);</pre>
5746:
1.30 cvs 5747: <div class="figure">
5748: <hr>
5749: <pre>| | | |
1.1 cvs 5750: | xx xxxx xxxx |x xxxx xxx xxxxx| x xxx x xxx |
5751: | xxx xxx xxxx x | x xx x xxx | xxxxx xxxx xx |
5752: | xxxxx xxxx |----------------| xxx xxxxx x |
5753: | xxxxx xxx xxxx | xxxx xx xx xxx | xx xx |
5754: | xxx xxxx x xxx | xxxx x xxx x |---------------|
5755: |----------------| xxx xxxx xxxxx | xxxxx xxxxx |
5756: | xxx xxx xxxxxx |----------------| xxx xxxx xxxx |
5757: | xxxx xxxx xx | xxxx xx x xx | xxx xx x xx |
5758: |----------------| xxx xxxxx xxxx | xxxx xxxx xxx |
5759: | xxxxx xxx xxxx | xxxx xx x xx | xxxxx xxx |
1.18 cvs 5760: |xxxx xx x xxxxxx| xxxx xx xxxxxx | xxxxx xxxxx |</pre>
1.19 cvs 5761:
1.30 cvs 5762: <p align="center"><em><a name="table">The design of a table</a></em></p>
5763: <hr>
5764: </div>
5765:
5766: <p>The presentation of the table should resemble the design of the above <a
5767: href="#table">figure</a>. It is defined by the following presentation
5768: schema fragment:</p>
5769: <pre>BOXES
1.1 cvs 5770: VertLine : BEGIN
5771: Width : 0.3 cm;
5772: Height : Enclosing . Height;
5773: VertPos : Top = Enclosing . Top;
5774: HorizPos : Left = Previous . Right;
5775: Content : Graphics 'v';
5776: END;
5777:
5778: HorizLine: BEGIN
5779: Width : Enclosing . Width;
5780: Height : 0.3 cm;
5781: VertPos : Top = Previous . Bottom;
5782: HorizPos : Left = Enclosing . Left;
5783: Content : Graphics 'h';
5784: END;
5785:
5786: RULES
1.6 cvs 5787: Column : BEGIN
5788: CreateBefore (VertLine);
5789: IF LAST CreateAfter (VertLine);
5790: Width : 2.8 cm;
5791: Height : Enclosed . Height;
5792: VertPos : Top = Enclosing . Top;
5793: HorizPos : Left = Previous . Right;
5794: END;
5795:
5796: Cell : BEGIN
5797: IF NOT FIRST CreateBefore (HorizLine);
5798: Width : Enclosing . Width;
5799: Height : Enclosed . Height;
5800: VertPos : Top = Previous . Bottom;
5801: HorizPos : Left = Enclosing . Left;
5802: Line;
5803: Adjust : VMiddle;
1.18 cvs 5804: END;</pre>
1.30 cvs 5805:
5806: <p>It is useful to note that the horizontal position rule of the first
5807: vertical line will not be applied, since there is no preceding box. In this
5808: case, the box is simply placed on the left side of the enclosing box.</p>
1.18 cvs 5809: </blockquote>
5810: </div>
5811:
5812: <div class="subsection">
1.30 cvs 5813: <h3><a name="sectc4233">Page layout</a></h3>
1.18 cvs 5814:
1.30 cvs 5815: <p>The page models specified in the <tt>Page</tt> rule are defined by boxes
1.18 cvs 5816: declared in the <tt>BOXES</tt> section of the presentation schema. Pages are
1.1 cvs 5817: not described as frames which will be filled by the document's text, but as
5818: element are inserted in the flow of the document and which mark the page
5819: breaks. Each of these page break elements contains presentation boxes which
5820: represent the footer boxes of a page followed by header boxes of the next
5821: page. The page box itself is the simple line which separates two pages on the
5822: screen. Both the footer and header boxes placed themselves with respect to
5823: this page box, with the footer being placed above it and the header boxes
1.18 cvs 5824: being placed above it.</p>
1.30 cvs 5825:
5826: <p>The boxes created by a page box are headers and footers and can only place
1.1 cvs 5827: themselves vertically with respect to the page box itself (which is in fact
5828: the separation between two pages). Besides, it is their vertical position
5829: rule which determines whether they are header or footer boxes. Header and
5830: footer boxes must have an explicit vertical position rule (they must not use
1.18 cvs 5831: the default rule).</p>
1.30 cvs 5832:
5833: <p>Footer boxes must have an absolute height or inherit the height of their
1.18 cvs 5834: contents:</p>
5835: <pre>Height : Enclosed . Height;</pre>
1.30 cvs 5836:
5837: <p>A page box must have height and width rules and these two rules must be
1.1 cvs 5838: specified with constant values, expressed in centimeters, inches, or
5839: typographer's points. These two rules are interpreted in a special way for
5840: page boxes: they determine the width of the page and the vertical distance
5841: between two page separators, which is the height of the page and its header
1.18 cvs 5842: and footer together.</p>
1.30 cvs 5843:
5844: <p>A page box should also have vertical and horizontal position rules and
5845: these two rules should specify the position on the sheet of paper of the
5846: rectangle enclosing the page's contents. These two rules must position the
5847: upper left corner of the enclosing rectangle in relation to the upper left
5848: corner of the sheet of paper, considered to be the enclosing element. In both
5849: rules, distances must be expressed in fixed units: centimeters (<tt>cm</tt>),
5850: inches (<tt>in</tt>), or typographer's points (<tt>pt</tt>). Thus, rules
5851: similar to the following should be found in the rules for a page box:</p>
1.18 cvs 5852: <pre>BOXES
1.1 cvs 5853: ThePage :
5854: BEGIN
5855: VertPos : Top = Enclosing . Top + 3 cm;
5856: HorizPos : Left = Enclosing . Left + 2.5 cm;
5857: Width : 16 cm;
5858: Height : 22.5 cm;
1.18 cvs 5859: END;</pre>
1.30 cvs 5860:
5861: <p>When a document must be page broken, the page models to be constructed are
1.18 cvs 5862: defined in the <tt>BOXES</tt> section of the presentation schema by declaring
5863: page boxes and header and footer boxes. Also, the <tt>Page</tt> rule is used
1.1 cvs 5864: to specify to which parts of the document and to which views each model should
1.18 cvs 5865: be applied.</p>
1.30 cvs 5866:
5867: <p>The <tt>Page</tt> rule has only one parameter, given between parentheses
5868: after the <tt>Page</tt> keyword. This parameter is the name of the box which
5869: must serve as the model for page construction. When a <tt>Page</tt> rule is
1.1 cvs 5870: attached to an element type, each time such an element appears in a document,
5871: a page break takes place and the page model indicated in the rule is applied
5872: to all following pages, until reaching the next element which has a
1.18 cvs 5873: <tt>Page</tt> rule.</p>
1.30 cvs 5874:
5875: <p>The <tt>Page</tt> rule applies to only one view; if it appears in the
5876: primary view's block of rules, a <tt>Page</tt> rule applies only to that view.
5877: Thus, different page models can be defined for the full document and for its
5878: table of contents, which is another view of the same document. Some views can
5879: be specified with pages, and other views of the same document can be specified
1.18 cvs 5880: without pages.</p>
5881: <pre> 'Page' '(' BoxID ')'</pre>
5882: </div>
5883:
5884: <div class="subsection">
1.30 cvs 5885: <h3><a name="sectc4234">Box copies</a></h3>
1.18 cvs 5886:
1.30 cvs 5887: <p>The <tt>Copy</tt> rule can be used for an element which is defined as a
1.7 cvs 5888: reference in the structure schema. In this case, the rule specifies, between
1.18 cvs 5889: parenthesis, the name of the box (declared in the <tt>BOXES</tt> section)
1.1 cvs 5890: which must be produced when this reference appears in the structure of a
5891: document. The box produced is a copy (same contents, but possible different
5892: presentation) of the box type indicated by the parameter between parentheses,
5893: and which is in the element designated by the reference. The name of a box
5894: can be replaced by type name. Then what is copied is the contents of the
1.18 cvs 5895: element of this type which is inside the referenced element.</p>
1.30 cvs 5896:
5897: <p>Whether a box name or type name is given, it may be followed by the name of
5898: a structure schema between parentheses. This signifies that the box or type
5899: is defined in the indicated structure schema and not in the structure schema
5900: with which the rule's presentation schema is associated.</p>
5901:
5902: <p>The <tt>Copy</tt> rule can also be applied to a presentation box. If the
1.1 cvs 5903: presentation box was created by a reference attribute, the rule is applied as
5904: in the case of a reference element: the contents of the box having the
1.18 cvs 5905: <tt>Copy</tt> rule are based on the element designated by the reference
5906: attribute. For other presentation boxes, the <tt>Copy</tt> rule takes a type
1.1 cvs 5907: name parameter which can be followed, between parentheses, by the name of the
5908: structure schema in which the type is defined, if it is not defined in the
5909: same schema. The contents of the box which has this rule are a copy of the
5910: element of this type which is in the element creating the presentation box, or
5911: by default, the box of this type which precedes the presentation box. This
5912: last facility is used, for example, to define the running titles in headers or
1.18 cvs 5913: footers.</p>
5914: <pre> 'Copy' '(' BoxTypeToCopy ')' .
1.1 cvs 5915: BoxTypeToCopy = BoxID [ ExtStruct ] /
1.6 cvs 5916: ElemID [ ExtStruct ] .
1.18 cvs 5917: ExtStruct = '(' ElemID ')' .</pre>
1.30 cvs 5918:
5919: <p>Like the creation rules, the <tt>Copy</tt> rule cannot appear in the <a
1.18 cvs 5920: href="#sectc427">default presentation rules</a>. Moreover, this rule can only
5921: appear in the primary view's block of rules; the copy rule is applied to all
5922: views.</p>
1.30 cvs 5923:
1.18 cvs 5924: <blockquote class="example">
1.30 cvs 5925: <p><strong>Example:</strong></p>
5926:
5927: <p>If the following definitions are in the structure schema:</p>
5928: <pre>Body = LIST OF (Chapter =
1.1 cvs 5929: BEGIN
5930: ChapterTitle = Text;
5931: ChapterBody = SectionSeq;
5932: END);
1.18 cvs 5933: RefChapter = REFERENCE (Chapter);</pre>
1.30 cvs 5934:
5935: <p>then the following presentation rules (among many other rules in the
5936: presentation schema) can be specified:</p>
5937: <pre>COUNTERS
1.1 cvs 5938: ChapterCtr : RANK OF Chapter;
5939: BOXES
5940: ChapterNumber :
5941: BEGIN
5942: Content : (VALUE (ChapterCtr, URoman));
5943: ...
5944: END;
5945: RULES
5946: Chapter :
5947: BEGIN
5948: CreateFirst (ChapterNumber);
5949: ...
5950: END;
5951: RefChapter :
5952: BEGIN
5953: Copy (ChapterNumber);
5954: ...
1.18 cvs 5955: END;</pre>
1.30 cvs 5956:
5957: <p>which makes the number of the chapter designated by the reference appear
5958: in uppercase roman numerals, in place of the reference to a chapter itself.
5959: Alternatively, the chapter title can be made to appear in place of the
5960: reference by writing this <tt>Copy</tt>rule:</p>
5961: <pre> Copy (ChapterTitle);</pre>
5962:
5963: <p>To define a header box, named <tt>RunningTitle</tt>, which contains the
5964: title of the current chapter, the box's contents are defined in this
5965: way:</p>
5966: <pre>BOXES
1.1 cvs 5967: RunningTitle :
1.18 cvs 5968: Copy (ChapterTitle);</pre>
5969: </blockquote>
5970: </div>
5971: </div>
5972: <hr>
5973: </div>
1.1 cvs 5974:
1.18 cvs 5975: <div class="chapter">
5976: <h1><a name="sect5">The T language</a></h1>
1.1 cvs 5977:
1.18 cvs 5978: <div class="section">
1.30 cvs 5979: <h2><a name="sectb51">Document translation</a></h2>
1.1 cvs 5980:
1.30 cvs 5981: <p>Because of its document model, Thot can produce documents in a high-level
1.18 cvs 5982: abstract form. This form, called the <em>canonical form</em> is specific to
1.1 cvs 5983: Thot; it is well suited to the editor's manipulations, but it does not
5984: necessarily suit other operations which might be applied to documents. Because
5985: of this, the Thot editor offers the choice of saving documents in its own form
5986: (the canonical form) or a format defined by the user. In the latter case, the
5987: Thot document is transformed by the translation program. This facility can
5988: also be used to export documents from Thot to systems using other
1.18 cvs 5989: formalisms.</p>
1.1 cvs 5990:
1.18 cvs 5991: <div class="subsection">
1.30 cvs 5992: <h3><a name="sectc511">Translation principles</a></h3>
1.1 cvs 5993:
1.30 cvs 5994: <p>Document translation allows the export of documents to other systems which
5995: do not accept Thot's canonical form. Translation can be used to export
5996: document to source-based formatters like T<sub><big>E</big></sub>X,
1.18 cvs 5997: L<sup>A</sup>T<sub><big>E</big></sub>X, and <tt>troff</tt>. It can also be
1.1 cvs 5998: used to translate documents into interchange formats like SGML or HTML. To
5999: allow the widest range of possible exports, Thot does not limit the choice of
6000: translations, but rather allows the user to define the formalisms into which
1.18 cvs 6001: documents can be translated.</p>
1.30 cvs 6002:
6003: <p>For each document or object class, a set of translation rules can be
6004: defined, specifying how the canonical form should be transformed into a given
1.18 cvs 6005: formalism. These translation rules are grouped into <em>translation
6006: schemas</em>, each schema containing the rules necessary to translate a
1.1 cvs 6007: generic logical structure (document or object structure) into a particular
6008: formalism. The same generic logical structure can have several different
6009: translation schemas, each defining translation rules for a different
1.18 cvs 6010: formalism.</p>
1.30 cvs 6011:
6012: <p>Like presentation schemas, translation schemas are generic. Thus, they
6013: apply to an entire object or document class and permit translation of all
6014: documents or objects of that class.</p>
1.18 cvs 6015: </div>
1.1 cvs 6016:
1.18 cvs 6017: <div class="subsection">
1.30 cvs 6018: <h3><a name="sectc512">Translation procedure</a></h3>
1.1 cvs 6019:
1.30 cvs 6020: <p>The translator works on the specific logical structure of the document
6021: being translated. It traverses the primary tree of this logical structure in
1.1 cvs 6022: pre-order and, at each node encountered, it applies the corresponding
6023: translation rules defined in the translation schema. Translation can be
1.18 cvs 6024: associated:</p>
6025: <ul>
1.30 cvs 6026: <li>with element types defined in the structure schema,</li>
6027: <li>with global or local attributes defined in the structure schema,</li>
6028: <li>with specific presentation rules,</li>
6029: <li>with the content of the leaves of the structure (characters, symbols
6030: and graphical elements)</li>
1.18 cvs 6031: </ul>
1.30 cvs 6032:
6033: <p>Thus, for each node, the translator applies all rules associated with the
1.1 cvs 6034: element type, all rules associated with each attribute (local or global)
6035: carried by the element, and if the element is a leaf of the tree, it also
1.10 cvs 6036: applies translation rules for characters, symbols, or graphical elements,
1.18 cvs 6037: depending on the type of the leaf.</p>
1.30 cvs 6038:
6039: <p>Rules associated with the content of leaves are different from all other
1.1 cvs 6040: rules: they specify only how to translate character strings, symbols, and
6041: graphical elements. All other rules, whether associated with element types,
6042: with specific presentation rules or with attributes, are treated similarly.
1.18 cvs 6043: These rules primarily allow:</p>
6044: <ul>
1.30 cvs 6045: <li>generation of a text constant or variable before or after the contents
6046: of an element,</li>
6047: <li>modification of the order in which elements appear after
6048: translation,</li>
6049: <li>removal of an element in the translated document,</li>
6050: <li>and writing messages on the user's terminal during translation.</li>
1.18 cvs 6051: </ul>
6052: </div>
6053: </div>
1.1 cvs 6054:
1.18 cvs 6055: <div class="section">
1.30 cvs 6056: <h2><a name="sectb52">Translation definition language</a></h2>
1.1 cvs 6057:
1.30 cvs 6058: <p>Translation schemas are written in a custom language, called T, which is
1.1 cvs 6059: described in the rest of this chapter. The grammar of T is specified using
1.18 cvs 6060: the same <a href="#sectc321">meta-language</a> as was used for the S and P
1.1 cvs 6061: languages and the translation schemas are written using the same conventions
6062: as the structure and presentation schemas. In particular, the keywords of the
6063: T language (the stings between apostrophes in the following syntax rules) can
6064: be written in any combination of upper-case and lower-case letters, but
6065: identifiers created by the programmer must always be written in the same
1.18 cvs 6066: way.</p>
1.1 cvs 6067:
1.18 cvs 6068: <div class="subsection">
1.30 cvs 6069: <h3><a name="sectc521">Organization of a translation schema</a></h3>
1.1 cvs 6070:
1.30 cvs 6071: <p>A translation schema is begun by the <tt>TRANSLATION</tt> keyword and is
1.18 cvs 6072: terminated by the <tt>END</tt> keyword. The <tt>TRANSLATION</tt> keyword is
1.1 cvs 6073: followed by the name of the generic structure for which a translation is being
6074: defined and a semicolon. This name must be identical to the name which
1.18 cvs 6075: appears after the <tt>STRUCTURE</tt> keyword in the corresponding structure
6076: schema.</p>
1.30 cvs 6077:
6078: <p>After this declaration of the structure, the following material appears in
1.18 cvs 6079: order:</p>
6080: <ul>
1.30 cvs 6081: <li>the length of lines produced by the translation,</li>
6082: <li>the character delimiting the end of the line,</li>
6083: <li>the character string which the translator will insert if it must
6084: line-break the translated text,</li>
6085: <li>declarations of
6086: <ul>
6087: <li>buffers,</li>
6088: <li>counters,</li>
6089: <li>constants,</li>
6090: <li>variables,</li>
6091: </ul>
6092: </li>
6093: <li>translation rules associated with element types,</li>
6094: <li>translation rules associated with attributes,</li>
6095: <li>translation rules associated with specific presentation rules,</li>
6096: <li>translation rules associated with characters strings, symbols and
6097: graphical elements.</li>
1.18 cvs 6098: </ul>
1.30 cvs 6099:
6100: <p>Each of these sections is introduced by a keyword followed by a sequence of
1.1 cvs 6101: declarations. All of these sections are optional, expect for the translation
1.18 cvs 6102: rules associated with element types. Many <tt>TEXTTRANSLATE</tt> sections can
1.1 cvs 6103: appear, each defining the rules for translating character strings of a
1.18 cvs 6104: particular alphabet.</p>
6105: <pre> TransSchema ='TRANSLATION' ElemID ';'
1.1 cvs 6106: [ 'LINELENGTH' LineLength ';' ]
6107: [ 'LINEEND' CHARACTER ';' ]
6108: [ 'LINEENDINSERT' STRING ';' ]
6109: [ 'BUFFERS' BufferSeq ]
6110: [ 'COUNTERS' CounterSeq ]
6111: [ 'CONST' ConstSeq ]
6112: [ 'VAR' VariableSeq ]
6113: 'RULES' ElemSeq
6114: [ 'ATTRIBUTES' AttrSeq ]
6115: [ 'PRESENTATION' PresSeq ]
1.30 cvs 6116: < 'TEXTTRANSLATE' TextTransSeq >
1.1 cvs 6117: [ 'SYMBTRANSLATE' TransSeq ]
6118: [ 'GRAPHTRANSLATE' TransSeq ]
1.18 cvs 6119: 'END' .</pre>
6120: </div>
1.1 cvs 6121:
1.18 cvs 6122: <div class="subsection">
1.30 cvs 6123: <h3><a name="sectc522">Line length</a></h3>
1.1 cvs 6124:
1.30 cvs 6125: <p>If a <tt>LINELENGTH</tt> instruction is present after the structure
1.1 cvs 6126: declaration, the translator divides the text it produces into lines, each line
6127: having a length less than or equal to the integer which follows the
1.18 cvs 6128: <tt>LINELENGTH</tt> keyword. This maximum line length is expressed as a
1.1 cvs 6129: number of characters. The end of the line is marked by the character defined
1.18 cvs 6130: by the <tt>LINEEND</tt> instruction. When the translator breaks the lines on
1.1 cvs 6131: a space character in generated text, this space will be replaced by the
1.18 cvs 6132: character string defined by the <tt>LINEENDINSERT</tt> instruction.</p>
1.30 cvs 6133:
6134: <p>If the <tt>LINEEND</tt> instruction is not defined then the linefeed
6135: character (octal code 12) is used as the default line end character. If the
1.18 cvs 6136: <tt>LINEENDINSERT</tt> instruction is not defined, the linefeed character is
6137: inserted at the end of the produced lines. If there is no <tt>LINELENGTH</tt>
1.1 cvs 6138: instruction, the translated text is not divided into lines. Otherwise, if the
6139: translation rules generate line end marks, these marks remain in the
6140: translated text, but the length of the lines is not controlled by the
1.18 cvs 6141: translator.</p>
6142: <pre> LineLength = NUMBER .</pre>
1.30 cvs 6143:
1.18 cvs 6144: <blockquote class="example">
1.30 cvs 6145: <p><strong>Example:</strong></p>
6146:
6147: <p>To limit the lines produced by the translator to a length of 80
6148: characters, the following rule is written at the beginning of the
6149: translation schema.</p>
6150: <pre>LineLength 80;</pre>
1.18 cvs 6151: </blockquote>
6152: </div>
1.1 cvs 6153:
1.18 cvs 6154: <div class="subsection">
1.30 cvs 6155: <h3><a name="sectc523">Buffers</a></h3>
1.1 cvs 6156:
1.30 cvs 6157: <p>A buffer is a unit of memory managed by the translator, which can either
1.18 cvs 6158: contain text read from the terminal during the translation (see the <a
6159: href="#sectc5212"><tt>Read</tt> rule</a>), or the name of the last picture
1.1 cvs 6160: (bit-map) encountered by the translator in its traversal of the document.
1.2 cvs 6161: Remember the pictures are stored in files that are separate for the document
1.1 cvs 6162: files and that the canonical form contains only the names of the files in
1.18 cvs 6163: which the pictures are found.</p>
1.30 cvs 6164:
6165: <p>Thus, there are two types of buffers: buffers for reading from the
6166: terminal (filled by the <tt>Read</tt> rule) and the buffer of picture names
6167: (containing the name of the last picture encountered). A translation schema
6168: can use either type, one or several read buffers and one (and only one)
6169: picture name buffer.</p>
6170:
6171: <p>If any buffers are used, the <tt>BUFFERS</tt> keyword must be present,
1.1 cvs 6172: followed by declarations of every buffer used in the translation schema. Each
6173: buffer declaration is composed only of the name of the buffer, chosen freely
1.2 cvs 6174: by the programmer. The picture name buffer is identified by the
1.18 cvs 6175: <tt>Picture</tt> keyword, between parentheses, following the buffer name. The
6176: <tt>Picture</tt> keyword may only appear once. Each buffer declaration is
6177: terminated by a semicolon.</p>
1.30 cvs 6178: <pre> BufferSeq = Buffer < Buffer > .
1.1 cvs 6179: Buffer = BufferID [ '(' 'Picture' ')' ] ';' .
1.18 cvs 6180: BufferID = NAME .</pre>
1.30 cvs 6181:
1.18 cvs 6182: <blockquote class="example">
1.30 cvs 6183: <p><strong>Example:</strong></p>
6184:
6185: <p>The following buffer declarations create a picture name buffer named
6186: <tt>pictureName</tt> and a read buffer named <a
6187: name="destname"><tt>DestName</tt></a>:</p>
6188: <pre>BUFFERS
1.18 cvs 6189: pictureName (Picture); DestName;</pre>
6190: </blockquote>
6191: </div>
1.1 cvs 6192:
1.18 cvs 6193: <div class="subsection">
1.30 cvs 6194: <h3><a name="sectc524">Counters</a></h3>
6195:
6196: <p>Certain translation rules generate text that varies according to the
6197: context of the element to which the rules apply. Variable text is defined
6198: either in the <a href="#sectc526"><tt>VAR</tt> section</a> of the translation
6199: schema or in the rule itself (see the <tt>Create</tt> and <tt>Write</tt>
6200: rules). Both types of definition rely on counters for the calculation of
6201: variable material.</p>
6202:
6203: <p>There are two types of counter: counters whose value is explicitely
6204: computed by applying <a href="#sectc5221"><tt>Set</tt> and <tt>Add</tt>
6205: rules</a>, and counters whose value is computed by a function associated with
6206: the counter. Those functions allow the same calculations as can be used in
6207: presentation schemas. As in a presentation schema, counters must be defined in
6208: the <tt>COUNTERS</tt> section of the translation schema before they are
6209: used.</p>
6210:
6211: <p>When counters are used in a translation schema, the <tt>COUNTERS</tt>
6212: keyword is followed by the declarations of every counter used. Each
6213: declaration is composed of the counter's name possibly followed by a colon and
6214: the counting function to be used for the counter. The declaration is
6215: terminated by a semi-colon. If the counter is explicitely computed by
6216: <tt>Set</tt> and <tt>Add</tt> rules, no counting function is indicated. If a
6217: counting function is indicated, <tt>Set</tt> and <tt>Add</tt> rules cannot be
6218: applied to that counter.</p>
1.1 cvs 6219:
1.30 cvs 6220: <p>The counting function indicates how the counter's value will be computed.
1.18 cvs 6221: Three functions are available: <tt>Rank</tt>, <tt>Rlevel</tt>, and
6222: <tt>Set</tt>.</p>
6223: <ul>
1.30 cvs 6224: <li><tt>Rank of ElemID</tt> indicates that the counter's value is the rank
6225: of the element of type <tt>ElemID</tt> which encloses the element for
6226: which the counter is being evaluated. For the purposes of this function,
6227: an element of type <tt>ElemID</tt> is considered to enclose itself. This
6228: function is primarily used when the element of type <tt>ElemID</tt> is
6229: part of an aggregate or list, in which case the counter's value is the
6230: element's rank in its list or aggregate. Note that, unlike the
6231: <tt>Rank</tt> function for presentation schemas, the <tt>Page</tt> keyword
6232: cannot be used in place of the <tt>ElemID</tt>.
6233: <p>The type name <tt>ElemID</tt> can be followed by an integer. That
6234: number represents the relative level, among the ancestors of the concerned
6235: element, of the element whose rank is asked. If that relative level
6236: <i>n</i> is unsigned, the <i>n<sup>th</sup></i> element of type
6237: <tt>ElemID</tt> encountered when travelling the logical structure from the
6238: root to the concerned element is taken into account. If the relative
6239: level is negative, the logical structure is travelled in the other
6240: direction, from the concerned element to the root.</p>
6241: </li>
6242: <li><tt>Rlevel of ElemID</tt> indicates that the counter's values is the
6243: relative level in the tree of the element for which the counter is being
6244: evaluated. The counter counts the number of elements of type
6245: <tt>ElemID</tt> which are found on the path between the root of the
6246: document's logical structure tree and the element (inclusive).</li>
6247: <li><tt>Set n on Type1 Add m on Type2</tt> indicates that the counter's
6248: value is calculated as follows: in traversing the document from the
6249: beginning to the element for which the counter is being evaluated, the
6250: counter is set to the value <tt>n</tt> each time a <tt>Type1</tt> element
6251: is encountered and is incremented by the amount <tt>m</tt> each time a
6252: <tt>Type2</tt> element is encountered. The initial value <tt>n</tt> and
6253: the increment <tt>m</tt> are integers.</li>
6254: </ul>
6255:
6256: <p>As in a presentation schema, the <tt>Rank</tt> and <tt>Set</tt> functions
6257: can be modified by a numeric attribute which changes their initial value. This
6258: is indicated by the <tt>Init</tt> keyword followed by the numeric attribute's
1.18 cvs 6259: name. The <tt>Set</tt> function takes the value of the attribute instead of
6260: the <tt>InitValue</tt> (<tt>n</tt>). For the <tt>Rank</tt> function, the
1.1 cvs 6261: value of the attribute is considered to be the rank of the first element of
6262: the list (rather than the normal value of 1). Subsequent items in the list
6263: have their ranks shifted accordingly. In both cases, the attribute must be
1.18 cvs 6264: numeric and must be a local attribute of the root of the document itself.</p>
1.30 cvs 6265: <pre> CounterSeq = Counter < Counter > .
1.1 cvs 6266: Counter = CounterID [ ':' CounterFunc ] ';' .
6267: CounterID = NAME .
6268: CounterFunc = 'Rank' 'of' ElemID [ SLevelAsc ]
6269: [ 'Init' AttrID ] /
6270: 'Rlevel' 'of' ElemID /
6271: 'Set' InitValue 'On' ElemID
6272: 'Add' Increment 'On' ElemID
6273: [ 'Init' AttrID ] .
6274: SLevelAsc = [ '-' ] LevelAsc .
6275: LevelAsc = NUMBER .
6276: InitValue = NUMBER .
6277: Increment = NUMBER .
6278: ElemID = NAME .
1.18 cvs 6279: AttrID = NAME .</pre>
1.30 cvs 6280:
1.18 cvs 6281: <blockquote class="example">
1.30 cvs 6282: <p><strong>Example:</strong></p>
6283:
6284: <p>If the body of a chapter is defined in the structure schema by:</p>
6285: <pre>Chapter_Body = LIST OF
1.1 cvs 6286: (Section = BEGIN
6287: Section_Title = Text;
6288: Section_Body = BEGIN
6289: Paragraphs;
6290: Section;
6291: END;
6292: END
1.18 cvs 6293: );</pre>
1.30 cvs 6294:
6295: <p>(sections are defined recursively), a counter can be defined giving the
6296: <a name="sectnum">number of a section</a> within its level in the
6297: hierarchy:</p>
6298: <pre>COUNTERS
1.18 cvs 6299: SectionNumber : Rank of Section;</pre>
1.30 cvs 6300:
6301: <p>A counter holding the hierarchic level of a section:</p>
6302: <pre> SectionLevel : Rlevel of Section;</pre>
6303:
6304: <p>A <a name="uniquenum">counter</a> which sequentially numbers all the
6305: document's sections, whatever their hierarchic level:</p>
6306: <pre> UniqueSectNum : Set 0 on Document Add 1 on Section;</pre>
1.18 cvs 6307: </blockquote>
6308: </div>
1.1 cvs 6309:
1.18 cvs 6310: <div class="subsection">
1.30 cvs 6311: <h3><a name="sectc525">Constants</a></h3>
1.1 cvs 6312:
1.30 cvs 6313: <p>A common feature of translation rules is the generation of constant text.
6314: This text can be defined in the rule that generates it (see for example the <a
1.18 cvs 6315: href="#sectc5210"><tt>Create</tt></a> and <a
6316: href="#sectc5211"><tt>Write</tt></a> rules); but it can also be defined once
6317: in the constant declaration section and used many times in different rules.
6318: The latter option is preferable when the same text is used in several rules or
6319: several <a href="#sectc526">variables</a>.</p>
1.30 cvs 6320:
6321: <p>The <tt>CONST</tt> keyword begins the constant declaration section of the
1.1 cvs 6322: translation schema. It must be omitted if no constants are declared. Each
6323: constant declaration is composed of the constant name, an equals sign, and the
6324: constant's value, which is a character string between apostrophes. A constant
1.18 cvs 6325: declaration is terminated by a semicolon.</p>
1.30 cvs 6326: <pre> ConstSeq = Const < Const > .
1.1 cvs 6327: Const = ConstID '=' ConstValue ';' .
6328: ConstID = NAME .
1.18 cvs 6329: ConstValue = STRING .</pre>
1.30 cvs 6330:
1.18 cvs 6331: <blockquote class="example">
1.30 cvs 6332: <p><strong><a name="levelexample">Example:</a></strong></p>
6333:
6334: <p>The following rule assigns the name <tt>TxtLevel</tt> to the character
6335: string ``Level'':</p>
6336: <pre>CONST
1.18 cvs 6337: TxtLevel = 'Level';</pre>
6338: </blockquote>
6339: </div>
1.1 cvs 6340:
1.18 cvs 6341: <div class="subsection">
1.30 cvs 6342: <h3><a name="sectc526">Variables</a></h3>
1.1 cvs 6343:
1.30 cvs 6344: <p>Variables allow to define variable text which is generated by the
1.18 cvs 6345: <tt>Create</tt> and <tt>Write</tt> rules. They are also used to define file
6346: names which are used in the <tt>Create</tt>, <tt>ChangeMainFile</tt>,
6347: <tt>RemoveFile</tt>, and <tt>Indent</tt> rules. Variables can be defined
6348: either in the <tt>VAR</tt> section of the translation schema or directly in
6349: the rules which use them. Variables that define file names must be declared
6350: in the <tt>VAR</tt> section, and when the same variable is used several times
6351: in the translation schema, it makes sense to define it globally in the
6352: <tt>VAR</tt> section. This section is only present if at least one variable
6353: is defined globally.</p>
1.30 cvs 6354:
6355: <p>After the <tt>VAR</tt> keyword, each global variable is defined by its
6356: name, a colon separator and a sequence of functions (at least one function).
6357: Each variable definition is terminated by a semicolon. Functions determine the
1.1 cvs 6358: different parts which together give the value of the variable. The value is
6359: obtained by concatenating the strings produced by each of the functions. Seven
6360: types of functions are available. Each variable definition may use any number
1.18 cvs 6361: of functions of each type.</p>
6362: <ul>
1.30 cvs 6363: <li>The function <tt>Value(Counter)</tt>returns a string representing the
6364: value taken by the counter when it is evaluated for the element in whose
6365: rule the variable is used. The counter must have been declared in the
6366: <tt>COUNTERS</tt> section of the translation schema. When the counter is
6367: expressed in arabic numerals, the counter name can be followed by a colon
6368: and an integer indicating a minimum length (number of characters) for the
6369: string; if the counter's value is normally expressed with fewer characters
6370: than the required minimum, zeroes are added to the front of the string to
6371: achieve the minimum length.
6372: <p>By default, the counter value is written in arabic digits. If another
6373: representation of that value is needed, the counter name must be followed
6374: by a comma and one of the following keywords:</p>
6375: <ul>
6376: <li><tt>Arabic</tt>: arabic numerals (default value),</li>
6377: <li><tt>LRoman</tt>: lower-case roman numerals,</li>
6378: <li><tt>URoman</tt>: upper-case roman numerals,</li>
6379: <li><tt>Uppercase</tt>: upper-case letter,</li>
6380: <li><tt>Lowercase</tt>: lower-case letter.</li>
6381: </ul>
6382: </li>
6383: <li>The function <tt>FileDir</tt>, without parameter, returns a string
6384: representing the name of the directory of the output file that has been
6385: given as a parameter to the translation program. The string includes a
6386: character '/' at the end.</li>
6387: <li>The function <tt>FileName</tt>, without parameter, returns a string
6388: representing the name of the output file that has been given as a
6389: parameter to the translation program. The file extension (the character
6390: string that terminate the file name, after a dot) is not part of that
6391: string.</li>
6392: <li>The function <tt>Extension</tt>, without parameter, returns a string
6393: representing the extension of the file name. That string is empty if the
6394: file name that has been given as a parameter to the translation program
6395: has no extension. If there is an extension, its first character is a
6396: dot.</li>
6397: <li>The function <tt>DocumentName</tt>, without parameter, returns a string
6398: representing the name of the document being translated.</li>
6399: <li>The function <tt>DocumentDir</tt>, without parameter, returns a string
6400: representing the directory containing the document being translated.</li>
6401: <li>The function formed by the name of a constant returns that constant's
6402: value.</li>
6403: <li>The function formed by a character string between apostrophes returns
6404: that string.</li>
6405: <li>The function formed by the name of a buffer returns the contents of that
6406: buffer. If the named buffer is the picture buffer, then the name of the
6407: last picture encountered is returned. Otherwise, the buffer is a read
1.31 cvs 6408: buffer and the value returned is text previously read from the terminal.
1.30 cvs 6409: If the buffer is empty (no picture has been encountered or the
6410: <tt>Read</tt> rule has not been executed for the buffer), then the empty
6411: string is returned.</li>
6412: <li>The function formed by an attribute name takes the value of the
6413: indicated attribute for the element to which the variable applies. If the
6414: element does not have that attribute, then the element's ancestor are
6415: searched toward the root of the tree. If one of the ancestors does have
6416: the attribute then its value is used. If no ancestors have the attribute,
6417: then the value of the function is the empty string.</li>
1.18 cvs 6418: </ul>
1.30 cvs 6419: <pre> VariableSeq = Variable < Variable > .
6420: Variable = VarID ':' Function < Function > ';' .
1.1 cvs 6421: VarID = NAME .
6422: Function ='Value' '(' CounterID [ ':' Length ]
6423: [ ',' CounterStyle ] ')' /
6424: 'FileDir' / 'FileName' / 'Extension' /
6425: 'DocumentName' / 'DocumentDir' /
6426: ConstID / CharString /
6427: BufferID / AttrID .
6428: Length = NUMBER .
6429: CounterStyle= 'Arabic' / 'LRoman' / 'URoman' /
6430: 'Uppercase' / 'Lowercase' .
1.18 cvs 6431: CharString = STRING .</pre>
1.30 cvs 6432:
1.18 cvs 6433: <blockquote class="example">
1.30 cvs 6434: <p><strong>Example:</strong></p>
6435:
6436: <p>To create, at the beginning of each section of the translated document,
6437: text composed of the string ``Section'' followed by the section number, the
6438: following <a name="varsectexample">variable definition</a> might be
6439: used:</p>
6440: <pre>VAR
1.18 cvs 6441: SectionVar : 'Section' Value(SectionNumber);</pre>
1.30 cvs 6442:
6443: <p>(see the definition of <a
6444: href="#sectnum"><tt>SectionNumber</tt></a>).</p>
6445:
6446: <p>The following variable definition can be used to create, at the beginning
6447: of each section, the text ``Level'' followed by the hierarchical level of
6448: the section. It used the constant defined above.</p>
6449: <pre> LevelVar : TxtLevel Value(SectionLevel);</pre>
6450:
6451: <p>(see the definitions of <a href="#sectnum"><tt>SectionLevel</tt></a> and
6452: of <a href="#levelexample"><tt>TxtLevel</tt></a>).</p>
6453:
6454: <p>To generate the translation of each section in a different file (see <a
6455: href="#sectc5220">rule <tt>ChangeMainFile</tt></a>), the name of these files
6456: might be defined by the following variable:</p>
6457: <pre> VarOutpuFile : FileName Value(SectionNumber)
1.18 cvs 6458: Extension;</pre>
1.30 cvs 6459:
6460: <p>If <tt>output.txt</tt> is the name of the <a name="varoutputfile">output
6461: file</a> specified when starting the translation program, translated
6462: sections are written in files <tt>output1.txt</tt>, <tt>output2.txt</tt>,
6463: etc.</p>
1.18 cvs 6464: </blockquote>
6465: </div>
6466:
6467: <div class="subsection">
1.30 cvs 6468: <h3><a name="sectc527">Translating structure elements</a></h3>
1.18 cvs 6469:
1.30 cvs 6470: <p>The <tt>RULES</tt> keyword introduces the translation rules which will be
1.1 cvs 6471: applied to the various structured element types. Translation rules can be
6472: specified for each element type defined in the structure schema, including the
1.18 cvs 6473: base types defined implicitly, whose names are <tt>TEXT_UNIT</tt>,
6474: <tt>PICTURE_UNIT</tt>, <tt>SYMBOL_UNIT</tt>, <tt>GRAPHIC_UNIT</tt> and
6475: <tt>PAGE_UNIT</tt>. But it is not necessary to specify rules for every
6476: defined type.</p>
1.30 cvs 6477:
6478: <p>If there are no translation rules for an element type, the elements that it
1.1 cvs 6479: contains (and which may have rules themselves) will still be translated, but
6480: the translator will produce nothing for the element itself. To make the
1.18 cvs 6481: translator completely ignore the content of an element the <a
6482: href="#sectc5217"><tt>Remove</tt> rule</a> must be used.</p>
1.30 cvs 6483:
6484: <p>The translation rules for an element type defined in the structure schema
6485: are written using the name of the type followed by a colon and the list of
1.18 cvs 6486: applicable rules. When the element type is a <a href="#sectd3285">mark
6487: pair</a>, but only in this case, the type name must be preceded by the
6488: <tt>First</tt> or <tt>Second</tt> keyword. This keyword indicates whether the
6489: rules that follow apply to the first or second mark of the pair.</p>
1.30 cvs 6490:
6491: <p>The list of rules can take several forms. It may be a simple
6492: non-conditional rule. It can also be formed by a condition followed by one or
6493: more simple rules. Or it can be a block of rules beginning with the
6494: <tt>BEGIN</tt> keyword and ending with the <tt>END</tt> keyword and a
6495: semicolon. This block of rules can contain one or more simple rules and/or
6496: one or more conditions, each followed by one or more simple rules.</p>
6497: <pre> ElemSeq = TransType < TransType > .
1.1 cvs 6498: TransType = [ FirstSec ] ElemID ':' RuleSeq .
6499: FirstSec = 'First' / 'Second' .
1.30 cvs 6500: RuleSeq = Rule / 'BEGIN' < Rule > 'END' ';' .
1.1 cvs 6501: Rule = SimpleRule / ConditionBlock .
6502: ConditionBlock = 'IF' ConditionSeq SimpleRuleSeq .
1.30 cvs 6503: SimpleRuleSeq = 'BEGIN' < SimpleRule > 'END' ';' /
1.18 cvs 6504: SimpleRule .</pre>
6505: </div>
1.1 cvs 6506:
1.18 cvs 6507: <div class="subsection">
1.30 cvs 6508: <h3><a name="sectc528">Conditional rules</a></h3>
1.1 cvs 6509:
1.30 cvs 6510: <p>In a translation schema, the translation rules are either associated with
1.1 cvs 6511: element types or with attribute values or with a specific presentation. They
6512: are applied by the translator each time an element of the corresponding type
6513: is encountered in the translated document or each time the attribute value is
6514: carried by an element or also, each time the specific translation is attached
6515: to an element. This systematic application of the rules can be relaxed: it is
6516: possible to add a condition to one or more rules, so that these rules are only
1.18 cvs 6517: applied when the condition is true.</p>
1.30 cvs 6518:
6519: <p>A condition begins with the keyword <tt>IF</tt>, followed by a sequence of
1.1 cvs 6520: elementary conditions. Elementary conditions are separated from each other by
1.18 cvs 6521: the <tt>AND</tt> keyword. If there is only one elementary condition, this
1.1 cvs 6522: keyword is absent. The rules are only applied if all the elementary
6523: conditions are true. The elementary condition can be negative; it is then
1.18 cvs 6524: preceded by the <tt>NOT</tt> keyword.</p>
1.30 cvs 6525:
6526: <p>When the translation rule(s) controlled by the condition apply to a
6527: reference element or a reference attribute, an elementary condition can also
6528: apply to element referred by this reference. The <tt>Target</tt> keyword is
6529: used for that purpose. It must appear before the keyword defining the
6530: condition type.</p>
6531:
6532: <p>Depending on their type, some conditions may apply either to the element
6533: with which they are associated, or to one of its ancestor. In the case of an
1.18 cvs 6534: ancestor, the key word <tt>Ancestor</tt> must be used, followed by</p>
6535: <ul>
1.30 cvs 6536: <li>either an integer which represents the number of levels in the tree
6537: between the element and the ancestor of interest,</li>
6538: <li>or the type name of the ancestor of interest. If that type is defined
6539: in a separate structure schema, the name of that schema must follow
6540: between parentheses.</li>
1.18 cvs 6541: </ul>
1.30 cvs 6542:
6543: <p>There is a special case for the parent element, which can be simply written
1.18 cvs 6544: <tt>Parent</tt> instead of <tt>Ancestor 1</tt>.</p>
1.30 cvs 6545:
6546: <p>Only conditions <tt>First</tt>, <tt>Last</tt>, <tt>Referred</tt>,
1.34 ! cvs 6547: <tt>Within</tt>, <tt>Attributes</tt>, <tt>Presentation</tt>, and those
! 6548: concerning an attribute or a specific presentation can apply to an ancestor.
! 6549: Conditions <tt>FirstRef</tt>, <tt>LastRef</tt>, <tt>ExternalRef</tt>,
! 6550: <tt>Alphabet</tt>, <tt>FirstAttr</tt>, <tt>LastAttr</tt>,
! 6551: <tt>ComputedPage</tt>, <tt>StartPage</tt>, <tt>UserPage</tt>,
! 6552: <tt>ReminderPage</tt>, <tt>Empty</tt> cannot be preceded by keywords
! 6553: <tt>Parent</tt> or <tt>Ancestor</tt>.</p>
1.30 cvs 6554:
6555: <p>In condition <tt>Referred</tt> and in the condition that applies to a named
1.18 cvs 6556: attribute, a symbol '<tt>*</tt>' can indicate that the condition is related
1.5 cvs 6557: only to the element itself. If this symbol is not present, not only the
1.18 cvs 6558: element is considered, but also its ancestor, at any level.</p>
1.30 cvs 6559:
6560: <p>The form of an elementary condition varies according to the type of
1.18 cvs 6561: condition.</p>
1.1 cvs 6562:
1.18 cvs 6563: <div class="subsubsection">
6564: <h4><a name="sectd5281">Conditions based on the logical position of the
6565: element</a></h4>
1.30 cvs 6566:
6567: <p>The condition can be on the position of the element in the document's
6568: logical structure tree. It is possible to test whether the element is the
6569: first (<tt>First</tt>) or last (<tt>Last</tt>) among its siblings or if it is
6570: not the first (<tt>NOT First</tt>) or not the last (<tt>NOT Last</tt>).</p>
6571:
6572: <p>It is also possible to test if the element is contained in an element of a
1.18 cvs 6573: given type (<tt>Within</tt>) or if it is not (<tt>NOT Within</tt>). If that
1.1 cvs 6574: element type is defined in a structure schema which is not the one which
6575: corresponds to the translation schema, the type name of this element must be
6576: followed, between parentheses, by the name of the structure schema which
1.18 cvs 6577: defines it.</p>
1.30 cvs 6578:
6579: <p>If the keyword <tt>Within</tt> is preceded by <tt>Immediately</tt>, the
1.18 cvs 6580: condition is satisfied only if the <em>parent</em> element has the type
6581: indicated. If the word <tt>Immediately</tt> is missing, the condition is
6582: satisfied if any <em>ancestor</em> has the type indicated.</p>
1.30 cvs 6583:
6584: <p>An integer <i>n</i> can appear between the keyword <tt>Within</tt> and the
1.1 cvs 6585: type. It specifies the number of ancestors of the indicated type that must be
6586: present for the condition to be satisfied. If the keyword
1.18 cvs 6587: <tt>Immediately</tt> is also present, the <i>n</i> immediate ancestors of the
6588: element must have the indicated type. The integer <i>n</i> must be positive
1.30 cvs 6589: or zero. It can be preceded by <tt><</tt> or <tt>></tt> to indicate a
1.1 cvs 6590: maximum or minimum number of ancestors. If these symbols are missing, the
1.18 cvs 6591: condition is satisfied only if it exists exactly <i>n</i> ancestors. When
1.30 cvs 6592: this number is missing, it is equivalent to > 0.</p>
6593:
6594: <p>If the condition applies to translation rules associated with an attribute,
1.18 cvs 6595: i.e. if it is in the <tt>ATTRIBUTES</tt> section of the presentation schema,
1.11 cvs 6596: the condition can be simply an element name. Translation rules are then
1.18 cvs 6597: executed only if the attribute is attached to an element of that type. The
6598: keyword <tt>NOT</tt> before the element name indicates that the translation
6599: rules must be executed only if the element is not of the type indicated.</p>
6600: </div>
1.1 cvs 6601:
1.18 cvs 6602: <div class="subsubsection">
1.30 cvs 6603: <h4><a name="sectd5282">Conditions on references</a></h4>
1.1 cvs 6604:
1.30 cvs 6605: <p>References may be taken into account in conditions, which can be based on
6606: the fact that the element, or one of its ancestors (unless symbol <tt>*</tt>
6607: is present), is designated by a at least one reference (<tt>Referred</tt>) or
6608: by none (<tt>NOT Referred</tt>). If the element or attribute to which the
1.1 cvs 6609: condition is attached is a reference, the condition can be based on the fact
6610: that it acts as the first reference to the designated element
1.18 cvs 6611: (<tt>FirstRef</tt>), or as the last (<tt>LastRef</tt>), or as a reference to
6612: an element located in another document (<tt>ExternalRef</tt>). Like all
6613: conditions, conditions on references can be inverted by the <tt>NOT</tt>
6614: keyword.</p>
6615: </div>
6616:
6617: <div class="subsubsection">
1.30 cvs 6618: <h4><a name="sectd5284">Conditions on the alphabets</a></h4>
1.1 cvs 6619:
1.30 cvs 6620: <p>The character string base type (and only this type) can use the condition
1.18 cvs 6621: <tt>Alphabet = a</tt> which indicates that the translation rule(s) should only
1.1 cvs 6622: apply if the alphabet of the character string is the one whose name appears
1.18 cvs 6623: after the equals sign (or is not, if there is a preceding <tt>NOT</tt>
1.1 cvs 6624: keyword). This condition cannot be applied to translation rules of an
1.18 cvs 6625: attribute.</p>
1.30 cvs 6626:
6627: <p>In the current implementation of Thot, the available alphabets are the
1.18 cvs 6628: <tt>Latin</tt> alphabet and the <tt>Greek</tt> alphabet.</p>
6629: </div>
1.1 cvs 6630:
1.18 cvs 6631: <div class="subsubsection">
1.30 cvs 6632: <h4><a name="sectd5285">Conditions on page breaks</a></h4>
1.1 cvs 6633:
1.30 cvs 6634: <p>The page break base type (and only this type) can use the following
1.18 cvs 6635: conditions: <tt>ComputedPage</tt>, <tt>StartPage</tt>, <tt>UserPage</tt>, and
6636: <tt>ReminderPage</tt>. The <tt>ComputedPage</tt> condition indicates that the
1.1 cvs 6637: translation rule(s) should apply if the page break was created automatically
1.18 cvs 6638: by Thot; the <tt>StartPage</tt> condition is true if the page break is
6639: generated before the element by the <tt>Page</tt> rule of the P language; the
6640: <tt>UserPage</tt> condition applies if the page break was inserted by the
6641: user; and the <tt>ReminderPage</tt> is applied if the page break is a reminder
6642: of page breaking.</p>
6643: </div>
1.1 cvs 6644:
1.18 cvs 6645: <div class="subsubsection">
1.30 cvs 6646: <h4><a name="sectd5286">Conditions on the element's content</a></h4>
1.1 cvs 6647:
1.30 cvs 6648: <p>The condition can be based on whether or not the element is empty. An
6649: element which has no children or whose leaves are all empty is considered to
6650: be empty itself. This condition is expressed by the <tt>Empty</tt> keyword,
6651: optionally preceded by the <tt>NOT</tt> keyword.</p>
1.18 cvs 6652: </div>
1.1 cvs 6653:
1.18 cvs 6654: <div class="subsubsection">
6655: <h4><a name="sectd5288">Conditions on the presence of specific presentation
6656: rules</a></h4>
1.30 cvs 6657:
6658: <p>The condition can be based on the presence or absence of specific
6659: presentation rules associated with the translated element, whatever the rules,
6660: their value or their number. This condition is expressed by the keyword
1.18 cvs 6661: <tt>Presentation</tt>, optionally preceded by the <tt>NOT</tt> keyword.</p>
6662: </div>
1.1 cvs 6663:
1.18 cvs 6664: <div class="subsubsection">
6665: <h4><a name="sectd5289">Conditions on the presence of logical
6666: attributes</a></h4>
1.30 cvs 6667:
6668: <p>In the same way, the condition can be based on the presence or absence of
1.1 cvs 6669: attributes associated with the translated elements, no matter what the
1.18 cvs 6670: attributes or their values. The <tt>Attributes</tt> keyword expresses this
6671: condition.</p>
6672: </div>
1.1 cvs 6673:
1.18 cvs 6674: <div class="subsubsection">
1.30 cvs 6675: <h4><a name="sectd52810">Conditions on logical attributes</a></h4>
1.1 cvs 6676:
1.30 cvs 6677: <p>If the condition appears in the translation rules of an attribute, the
1.18 cvs 6678: <tt>FirstAttr</tt> and <tt>LastAttr</tt> keywords can be used to indicate that
1.1 cvs 6679: the rules must only be applied if this attribute is the first attribute for
6680: the translated element or if it is the last (respectively). These conditions
1.18 cvs 6681: can also be inverted by the <tt>NOT</tt> keyword.</p>
1.30 cvs 6682:
6683: <p>Another type of condition can only be applied to the translation rules when
1.18 cvs 6684: the element being processed (or one of its ancestors if symbol <tt>*</tt> is
1.1 cvs 6685: missing) has a certain attribute, perhaps with a certain value or, in
6686: contrast, when the element does not have this attribute with this value. The
6687: condition is specified by writing the name of the attribute after the keyword
1.18 cvs 6688: <tt>IF</tt> or <tt>AND</tt>. The <tt>NOT</tt> keyword can be used to invert
1.1 cvs 6689: the condition. If the translation rules must be applied to any element which
6690: has this attribute (or does not have it, if the condition is inverted) no
6691: matter what the attribute's value, the condition is complete. If, in
6692: contrast, the condition applies to one or more values of the attribute, these
6693: are indicated after the name of the attribute, except for reference attributes
1.18 cvs 6694: which do not have values.</p>
1.30 cvs 6695:
6696: <p>The representation of the values of an <a name="relattr">attribute</a> in a
1.1 cvs 6697: condition depends on the attribute's type. For attributes with enumerated or
6698: textual types, the value (a name or character string between apostrophes,
6699: respectively) is simply preceded by an equals sign. For numeric attributes,
6700: the condition can be based on a single value or on a range of values. In the
6701: case of a unique value, this value (an integer) is simply preceded by an
1.18 cvs 6702: equals sign. Conditions based on ranges of values have several forms:</p>
6703: <ul>
1.30 cvs 6704: <li>all values less than a given value (the value is preceded by a ``less
6705: than'' sign).</li>
6706: <li>all values greater than a given value (the value is preceded by a
6707: ``greater than'' sign).</li>
6708: <li>all values falling in an interval, bounds included. The range of values
6709: is then specified <tt>IN [</tt>Minimum <tt>..</tt>Maximum<tt>]</tt>, where
6710: Minimum and Maximum are integers.</li>
1.18 cvs 6711: </ul>
1.30 cvs 6712:
6713: <p>All numeric values may be negative. The integer is simply preceded by a
6714: minus sign.</p>
6715:
6716: <p>Both local and global attributes can be used in conditions.</p>
1.18 cvs 6717: </div>
1.1 cvs 6718:
1.18 cvs 6719: <div class="subsubsection">
1.30 cvs 6720: <h4><a name="sectd52811">Conditions on specific presentation rules</a></h4>
1.1 cvs 6721:
1.30 cvs 6722: <p>It is possible to apply translation rules only when the element being
1.1 cvs 6723: processed has or does not have a specific presentation rule, possibly with a
6724: certain value. The condition is specified by writing the name of the
1.18 cvs 6725: presentation rule after the keyword <tt>IF</tt> or <tt>AND</tt>. The
6726: <tt>NOT</tt> keyword can be used to invert the condition. If the translation
1.1 cvs 6727: rules must be applied to any element which has this presentation rule (or does
6728: not have it, if the condition is inverted) no matter what the rule's value,
6729: the condition is complete. If, in contrast, the condition applies to one or
6730: more values of the rule, these are indicated after the name of the
1.18 cvs 6731: attribute.</p>
1.30 cvs 6732:
6733: <p>The representation of presentation rule values in a condition is similar to
1.1 cvs 6734: that for attribute values. The representation of these values depend on the
6735: type of the presentation rule. There are three categories of presentation
1.18 cvs 6736: rules:</p>
6737: <ul>
1.30 cvs 6738: <li>those taking numeric values (<tt>Size, Indent, LineSpacing,
6739: LineWeight</tt>),</li>
6740: <li>those with values taken from a predefined list (<tt>Adjust, Justify,
6741: Hyphenate, Style, Weight, Font, UnderLine, Thickness,
6742: LineStyle</tt>),</li>
6743: <li>those whose value is a name (<tt>FillPattern, Background,
6744: Foreground</tt>).</li>
1.18 cvs 6745: </ul>
1.30 cvs 6746:
6747: <p>For presentation rules which take numeric values, the condition can take a
1.1 cvs 6748: unique value or a range of values. In the case of a unique value, this value
6749: (an integer) is simply preceded by an equals sign. Conditions based on ranges
1.18 cvs 6750: of values have several forms:</p>
6751: <ul>
1.30 cvs 6752: <li>all values less than a given value (the value is preceded by a ``less
6753: than'' sign).</li>
6754: <li>all values greater than a given value (the value is preceded by a
6755: ``greater than'' sign).</li>
6756: <li>all values falling in an interval, bounds included. The range of values
6757: is then specified <tt>IN [</tt>Minimum <tt>..</tt>Maximum<tt>]</tt>, where
6758: Minimum and Maximum are integers.</li>
1.18 cvs 6759: </ul>
1.30 cvs 6760:
6761: <p>Values for the <tt>Indent</tt>rule may be negative. The integer is then
1.2 cvs 6762: simply preceded by a minus sign and represents how far the first line starts
1.18 cvs 6763: to the left of the other lines.</p>
1.30 cvs 6764:
6765: <p>For presentation rules whose values are taken from predefined lists, the
6766: value which satisfies the condition is indicated by an equals sign followed by
6767: the name of the value.</p>
6768:
6769: <p>For presentation rule whose values are names, the value which satisfies the
1.1 cvs 6770: condition is indicated by the equals sign followed by the value's name. The
1.18 cvs 6771: names of fill patterns (the <tt>FillPattern</tt> rule) and of colors (the
6772: <tt>Foreground</tt> and <tt>Background</tt> rules) known to Thot are the same
6773: as in the P language.</p>
1.30 cvs 6774:
6775: <p>The syntax of conditions based on the specific presentation is the same as
6776: the syntax used to express the <a href="#sectc5224">translation of specific
1.18 cvs 6777: presentation rules</a>.</p>
1.30 cvs 6778:
6779: <p>When a condition has only one rule, the condition is simply followed by
6780: that rule. If it has several rules, they are placed after the condition
6781: between the keywords <tt>BEGIN</tt> and <tt>END</tt>.</p>
1.18 cvs 6782: <pre> ConditionSeq = Condition [ 'AND' Condition ] .
1.1 cvs 6783: Condition = [ 'NOT' ] [ 'Target' ] Cond .
6784: Cond = CondElem / CondAscend .
6785: CondElem ='FirstRef' / 'LastRef' /
6786: 'ExternalRef' /
6787: 'Alphabet' '=' Alphabet /
6788: 'ComputedPage' / 'StartPage' /
6789: 'UserPage' / 'ReminderPage' /
6790: 'Empty' /
1.11 cvs 6791: ElemID /
1.1 cvs 6792: 'FirstAttr' / 'LastAttr' .
6793: CondAscend = [ Ascend ] CondOnAscend .
6794: Ascend = '*' / 'Parent' / 'Ancestor' LevelOrType .
6795: LevelOrType = CondRelLevel / ElemID [ ExtStruct ] .
6796: CondRelLevel = NUMBER .
6797: CondOnAscend ='First' / 'Last' /
6798: 'Referred' /
6799: [ 'Immediately' ] 'Within' [ NumParent ]
6800: ElemID [ ExtStruct ] /
6801: 'Attributes' /
6802: AttrID [ RelatAttr ] /
6803: 'Presentation' /
1.34 ! cvs 6804: PresRule .
1.1 cvs 6805: NumParent = [ GreaterLess ] NParent .
1.30 cvs 6806: GreaterLess = '>' / '<' .
1.1 cvs 6807: NParent = NUMBER.
6808: ExtStruct = '(' ElemID ')' .
6809: Alphabet = NAME .
6810: RelatAttr ='=' Value /
1.30 cvs 6811: '>' [ '-' ] Minimum /
1.1 cvs 6812: '<' [ '-' ] Maximum /
6813: 'IN' '[' [ '-' ] MinInterval '..'
6814: [ '-' ] MaxInterval ']' .
6815: Value = [ '-' ] IntegerVal / TextVal / AttrValue .
6816: Minimum = NUMBER .
6817: Maximum = NUMBER .
6818: MinInterval = NUMBER .
6819: MaxInterval = NUMBER .
6820: IntegerVal = NUMBER .
6821: TextVal = STRING .
1.18 cvs 6822: AttrValue = NAME .</pre>
1.30 cvs 6823:
1.18 cvs 6824: <blockquote class="example">
1.30 cvs 6825: <p><strong>Example:</strong></p>
6826:
6827: <p>Suppose that after each element of type Section_Title it is useful to
6828: produce the text <tt>\label{SectX}</tt> where <tt>X</tt> represents the
6829: section number, but only if the section is designated by one or more
6830: references in the document. The following conditional rule produces this
6831: effect:</p>
6832: <pre>RULES
1.1 cvs 6833: Section_Title :
6834: IF Referred
1.18 cvs 6835: Create ('\label{Sect' Value(UniqueSectNum) '}\12') After;</pre>
1.30 cvs 6836:
6837: <p>(the declaration of the <a href="#sectc5224"><tt>UniqueSectNum</tt>
6838: counter</a> is given above). The string <tt>\12</tt> represents a line
6839: break.</p>
1.18 cvs 6840: </blockquote>
1.30 cvs 6841:
1.18 cvs 6842: <blockquote class="example">
1.30 cvs 6843: <p><strong>Example:</strong></p>
6844:
6845: <p>Suppose that for elements of the Elmnt type it would be useful to produce
6846: a character indicating the value of the numeric attribute Level associated
6847: with the element: an ``A'' for all values of Level less than 3, a ``B'' for
6848: values between 3 and 10 and a ``C'' for values greater than 10. This can be
6849: achieved by writing the following rules for the Elmnt type:</p>
6850: <pre>RULES
1.1 cvs 6851: Elmnt :
6852: BEGIN
6853: IF Level < 3
6854: Create 'A';
6855: IF Level IN [3..10]
6856: Create 'B';
1.30 cvs 6857: IF Level > 10
1.1 cvs 6858: Create 'C';
1.18 cvs 6859: END;</pre>
6860: </blockquote>
6861: </div>
6862: </div>
1.1 cvs 6863:
1.18 cvs 6864: <div class="subsection">
1.30 cvs 6865: <h3><a name="sectc529">Translation rules</a></h3>
1.1 cvs 6866:
1.30 cvs 6867: <p>Fifteen types of translation rules can be associated with element types and
1.18 cvs 6868: attribute values. They are the <tt>Create</tt>, <tt>Write</tt>,
6869: <tt>Read</tt>, <tt>Include</tt>, <tt>Get</tt>, <tt>Copy</tt>, <tt>Use</tt>,
1.31 cvs 6870: <tt>Remove</tt>, <tt>Ignore</tt>, <tt>NoTranslation</tt>,
6871: <tt>NoLineBreak</tt>, <tt>ChangeMainFile</tt>, <tt>RemoveFile</tt>,
6872: <tt>Set</tt>, <tt>Add</tt>, <tt>Indent</tt>, rules. Each rule has its own
6873: syntax, although they are all based on very similar models.</p>
1.18 cvs 6874: <pre> SimpleRule = 'Create' [ 'IN' VarID ] Object
1.1 cvs 6875: [ Position ] ';' /
6876: 'Write' Object [ Position ] ';' /
6877: 'Read' BufferID [ Position ] ';' /
6878: 'Include' File [ Position ] ';' /
6879: 'Get' [ RelPosition ] ElemID
6880: [ ExtStruct ]
6881: [ Position ] ';' /
6882: 'Copy' [ RelPosition ] ElemID
6883: [ ExtStruct ]
6884: [ Position ] ';' /
6885: 'Use' TrSchema [ 'For' ElemID ] ';' /
6886: 'Remove' ';' /
1.31 cvs 6887: 'Ignore' ';' /
1.1 cvs 6888: 'NoTranslation' ';' /
6889: 'NoLineBreak' ';' /
6890: 'ChangeMainFile' VarID [ Position ] ';' /
1.14 cvs 6891: 'RemoveFile' VarID [ Position ] ';' /
1.10 cvs 6892: 'Set' CounterID InitValue [ Position ] ';' /
6893: 'Add' CounterID Increment [ Position ] ';' /
1.25 cvs 6894: 'Indent' [ 'IN' VarID ] Indent [ Position ] ';' .</pre>
1.18 cvs 6895: </div>
6896:
6897: <div class="subsection">
1.30 cvs 6898: <h3><a name="sectc5210">The <tt>Create</tt> rule</a></h3>
1.18 cvs 6899:
1.30 cvs 6900: <p>The most frequently used rule is undoubtedly the <tt>Create</tt> rule,
6901: which generates fixed or variable text (called an <em>object</em>) in the
6902: output file. The generated text can be made to appear either before or after
6903: the content of the element to which the rule applies. The rule begins with the
1.18 cvs 6904: <tt>Create</tt> keyword, followed by a specifier for the object and a keyword
6905: (<tt>Before</tt> or <tt>After</tt>) indicating the position of the generated
6906: text (<a href="#sectc5222">before or after</a> the element's content). If the
1.1 cvs 6907: position is not indicated, the object will be generated before the element's
6908: content. This rule, like all translation rules, is terminated by a
1.18 cvs 6909: semicolon.</p>
1.30 cvs 6910:
6911: <p>The <tt>Create</tt> keyword can be followed by the <tt>IN</tt> keyword and
6912: by the name of a variable. This means that the text generated by the rule
6913: must not be written in the main output file, but in the file whose name is
1.18 cvs 6914: specified by the variable.</p>
1.30 cvs 6915:
6916: <p>This allows the translation program to generate text in different files
6917: during the same run. These files do not need to be explicitely declared or
6918: opened. They do not need to be closed either, but if they contain temporary
6919: data, they can be removed (see the <a href="#sectc5220a"><tt>RemoveFile</tt>
6920: rule</a>). As soon as the translation program executes a <tt>Create</tt> rule
6921: for a file that is not yet open, it opens the file. These files are closed
6922: when the translation is finished.</p>
1.18 cvs 6923: <pre> 'Create' [ 'IN' VarID ] Object
1.1 cvs 6924: [ Position ] ';'
6925: Object = ConstID / CharString /
6926: BufferID /
6927: VarID /
1.30 cvs 6928: '(' Function < Function > ')' /
1.21 cvs 6929: [ 'Translated' ] AttrID /
1.1 cvs 6930: 'Value' /
6931: 'Content' /
6932: 'Attributes' /
6933: 'Presentation' /
6934: 'RefId' /
6935: 'PairId' /
6936: 'FileDir' /
6937: 'FileName' /
6938: 'Extension' /
6939: 'DocumentName' /
6940: 'DocumentDir' /
6941: [ 'Referred' ] ReferredObject .
6942: Position ='After' / 'Before' .
6943:
6944: ReferredObject = VarID /
6945: ElemID [ ExtStruct ] /
6946: 'RefId' /
6947: 'DocumentName' /
1.18 cvs 6948: 'DocumentDir' .</pre>
1.30 cvs 6949:
6950: <p>The object to be generated can be:</p>
1.18 cvs 6951: <ul>
1.30 cvs 6952: <li>a constant string, specified by its name if it is declared in the
6953: schema's <tt>CONST</tt> section, or given directly as a value between
6954: apostrophes;</li>
6955: <li>the contents of a buffer, designated by the name of the buffer;</li>
6956: <li>a variable, designated by its name if it is declared in the translation
6957: schema's <tt>VAR</tt> section, or given directly between parentheses. The
6958: text generated is the value of that variable evaluated for the element to
6959: which the rule applies.</li>
6960: <li>the value of an attribute, if the element being translated has this
6961: attribute. The attribute is specified by its name. If it's a text
6962: attribute, it can be preceded by the <code>Translated</code> keyword,
6963: which causes the attribute value to be recoded using the text translation
6964: table defined by section <code><a
6965: href="#sectc5225">TEXTTRANSLATE</a></code>;</li>
6966: <li>the value of a specific presentation rule. This object can only be
6967: generated if the translation rule is for a <a href="#prestransl">specific
6968: presentation rule</a>. It is specified by the <tt>Value</tt>
6969: keyword;</li>
6970: <li>the element's content. That is, the content of the leaves of the
6971: subtree of the translated element. This is specified by the
6972: <tt>Content</tt> keyword;</li>
6973: <li>the translation of all attributes of the element (which is primarily
6974: used to apply the attribute translation rules <a
6975: href="#sectc5222">before</a> those of the element type). This is
6976: specified by the <tt>Attributes</tt> keyword.</li>
6977: <li>the translation of all of the element's specific presentation rules
6978: (which is primarily used to apply the translation rules for the specific
6979: presentation rules <a href="#sectc5222">before</a> those of the element or
6980: its attributes). This option is specified by the <tt>Presentation</tt>
6981: keyword;</li>
6982: <li>The value of the reference's identifier.<br>
6983: Thot associates a unique identifier with each element in a document. This
6984: identifier (called <em>reference's identifier</em> or <em>label</em>) is a
6985: character string containing the letter `L' followed by digits. Thot uses
6986: it in references for identifying the referred element.<br>
6987: The <tt>RefId</tt> keyword produces the reference's identifier of the
6988: element to which the translation rule is applied, or the reference's
6989: identifier of its first ancestor that is referred by a reference or that
6990: can be referred by a reference.</li>
6991: <li>the value of a mark pair's unique identifier. This may only be used for
6992: <a href="#sectd3285">mark pairs</a> and is indicated by the
6993: <tt>PairId</tt> keyword.</li>
6994: <li>the directory containing the file being generated (this string includes
6995: an ending '/', if it is not empty). This is indicated by the
6996: <tt>FileDir</tt> keyword.</li>
6997: <li>the name of the file being generated (only the name, without the
6998: directory and without the extension). This is indicated by the
6999: <tt>FileName</tt> keyword.</li>
7000: <li>the extension of the file being generated (this string starts with a
7001: dot, if it is not empty). This is indicated by the <tt>Extension</tt>
7002: keyword.</li>
7003: <li>the name of the document being translated. This is indicated by the
7004: <tt>DocumentName</tt> keyword.</li>
7005: <li>the directory containing the document being translated. This is
7006: indicated by the <tt>DocumentDir</tt> keyword.</li>
1.18 cvs 7007: </ul>
1.30 cvs 7008:
7009: <p>When the rule applies to a reference (an element or an attribute defined as
7010: a reference in the structure schema), it can generate a text related to the
1.21 cvs 7011: element referred by that reference. The rule name is then followed by the
1.18 cvs 7012: <tt>Referred</tt> keyword and a specification of the object to be generated
7013: for the referred element. This specification can be:</p>
7014: <ul>
1.30 cvs 7015: <li>the name of a variable. The rule generates the value of that variable,
7016: computed for the referred element.</li>
7017: <li>an element type. The rule generates the translation of the element of
7018: that type, which is in the subtree of the referred element. If this
7019: element is not defined in the structure schema which corresponds to the
7020: translation schema (that is, an object defined in another schema), the
7021: element's type name must be followed by the name of its structure schema
7022: between parentheses.</li>
7023: <li>the <tt>RefId</tt> keyword. The rule generates the reference's
7024: identifier of the referred element.</li>
7025: <li>the <tt>DocumentName</tt> keyword. The rule generates the name of the
7026: document to which the referred element belongs.</li>
7027: <li>the <tt>DocumentDir</tt> keyword. The rule generates the name of the
7028: directory that contains the document of the referred element.</li>
1.18 cvs 7029: </ul>
7030: </div>
1.1 cvs 7031:
1.18 cvs 7032: <div class="subsection">
1.30 cvs 7033: <h3><a name="sectc5211">The <tt>Write</tt> rule</a></h3>
1.1 cvs 7034:
1.30 cvs 7035: <p>The <tt>Write</tt> has the same syntax as the <tt>Create</tt> rule. It
7036: also produces the same effect, but the generated text is displayed on the
7037: user's terminal during the translation of the document, instead of being
7038: produced in the translated document. This is useful for helping the user keep
7039: track of the progress of the translation and for prompting the user on the
7040: terminal for input required by the <tt>Read</tt> rule.</p>
1.18 cvs 7041: <pre> 'Write' Object [ Position ] ';'</pre>
1.30 cvs 7042:
7043: <p>Notice: if the translator is launched by the editor (by the ``Save as''
1.18 cvs 7044: command), messages produced by the <tt>Write</tt> rule are not displayed.</p>
1.30 cvs 7045:
1.18 cvs 7046: <blockquote class="example">
1.30 cvs 7047: <p><strong>Example:</strong></p>
7048:
7049: <p>To make the translator display the number of each section being
7050: translated on the user's terminal, the following rule is specified for the
7051: <tt>Section</tt> element type:</p>
7052: <pre>Section : BEGIN
1.1 cvs 7053: Write VarSection;
7054: ...
1.18 cvs 7055: END;</pre>
1.30 cvs 7056:
7057: <p>(see <a href="#varsectexample">above</a> for the definition of the
7058: <tt>VarSection</tt> variable).</p>
7059:
7060: <p>To display text on the terminal before issuing a read operation with the
7061: <tt>Read</tt> rule, the following rule is used:</p>
7062: <pre>BEGIN
1.1 cvs 7063: Write 'Enter the name of the destination: ';
7064: ...
1.18 cvs 7065: END;</pre>
7066: </blockquote>
7067: </div>
7068:
7069: <div class="subsection">
1.30 cvs 7070: <h3><a name="sectc5212">The <tt>Read</tt> rule</a></h3>
1.18 cvs 7071:
1.30 cvs 7072: <p>The <tt>Read</tt> rule reads text from the terminal during the translation
7073: of the document and saves the text read in one of the buffers declared in the
1.18 cvs 7074: <tt>BUFFERS</tt> section of the schema. The buffer to be used is indicated by
7075: its name, after the <tt>READ</tt> keyword. This name can be followed, as in
7076: the <tt>Create</tt> and <tt>Write</tt> rules, by a keyword indicating if the
7077: read operation must be performed <tt>Before</tt> or <tt>After</tt> the
1.1 cvs 7078: translation of the element's content. If this keyword is absent, the read
7079: operation is done beforehand. The text is read into the buffer and remains
1.5 cvs 7080: there until a rule using the same buffer - possibly the same rule - is
1.18 cvs 7081: applied.</p>
7082: <pre> 'Read' BufferID [ Position ] ';'</pre>
1.30 cvs 7083:
1.18 cvs 7084: <blockquote class="example">
1.30 cvs 7085: <p><strong>Example:</strong></p>
7086:
7087: <p>The following set of rules tells the user that the translator is waiting
7088: for the entry of some text, reads this text into a buffer and copies the
7089: text into the translated document.</p>
7090: <pre>BEGIN
1.1 cvs 7091: Write 'Enter the name of the destination: ';
7092: Read DestName;
7093: Create DestName;
7094: ...
1.18 cvs 7095: END;</pre>
1.30 cvs 7096:
7097: <p>(see <a href="#destname">above</a> the definition of
7098: <tt>DestName</tt>).</p>
1.18 cvs 7099: </blockquote>
7100: </div>
7101:
7102: <div class="subsection">
1.30 cvs 7103: <h3><a name="sectc5213">The <tt>Include</tt> rule</a></h3>
1.18 cvs 7104:
1.30 cvs 7105: <p>The <tt>Include</tt> rule, like the <tt>Create</tt> rule, is used to
7106: produce text in the translated document. It inserts constant text which is
7107: not defined in the translation schema, but is instead taken from a file. The
1.18 cvs 7108: file's name is specified after the <tt>Include</tt> keyword, either directly
1.1 cvs 7109: as a character string between apostrophes or as the name of one of the buffers
1.18 cvs 7110: declared in the <tt>BUFFERS</tt> section of the schema. In the latter case,
1.1 cvs 7111: the buffer is assumed to contain the file's name. This can be used when the
7112: included file's name is known only at the moment of translation. This only
1.18 cvs 7113: requires that the <tt>Include</tt> rule is preceded by a <tt>Read</tt> rule
7114: which puts the name of the file desired by the user into the buffer.</p>
1.30 cvs 7115:
7116: <p>Like the other rules, it is possible to specify whether the inclusion will
1.1 cvs 7117: occur before or after the element's content, with the default being before.
7118: The file inclusion is only done at the moment of translation, not during the
7119: compilation of the translation schema. Thus, the file to be included need not
7120: exist during the compilation, but it must be accessible at the time of
7121: translation. Its contents can also be modified between two translations, thus
7122: producing different results, even if neither the document or the translation
1.18 cvs 7123: schema are modified.</p>
1.30 cvs 7124:
7125: <p>During translation, the file to be included is searched for along the
7126: schema directory path (indicated by the environment variable
7127: <tt>THOTSCH</tt>). The file name is normally only composed of a simple name,
7128: without specification of a complete file path. However, if the filename
7129: starts with a '/', it is considered as an absolute path.</p>
1.18 cvs 7130: <pre> 'Include' File [ Position ] ';'
1.6 cvs 7131: File = FileName / BufferID .
1.18 cvs 7132: FileName = STRING .</pre>
1.30 cvs 7133:
1.18 cvs 7134: <blockquote class="example">
1.30 cvs 7135: <p><strong>Example:</strong></p>
7136:
7137: <p>Suppose that it is desirable to print documents of the Article class with
7138: a formatter which requires a number of declarations and definitions at the
7139: beginning of the file. The <tt>Include</tt>rule can be used to achieve
7140: this. All the declarations and definitions a replaced in a file called
7141: <tt>DeclarArt</tt> and then the <tt>Article</tt> element type is given the
7142: following rule:</p>
7143: <pre>Article : BEGIN
1.1 cvs 7144: Include 'DeclarArt' Before;
7145: ...
1.18 cvs 7146: END;</pre>
7147: </blockquote>
7148: </div>
7149:
7150: <div class="subsection">
1.30 cvs 7151: <h3><a name="sectc5214">The <tt>Get</tt> rule</a></h3>
1.18 cvs 7152:
1.30 cvs 7153: <p>The <tt>Get</tt> rule is used to change the order in which the elements
7154: appear in the translated document. More precisely, it produces the
7155: translation of a specified element before or after the translation of the
7156: content of the element to which the rule applies. The <tt>Before</tt> and
7157: <tt>After</tt> keywords are placed at the end of the rule to specify whether
7158: the operation should be performed before or after translation of the rule's
7159: element (the default is before). The type of the element to be moved must be
7160: specified after the <tt>Get</tt> keyword, optionally preceded by a keyword
7161: indicating where the element will be found in the logical structure of the
7162: document:</p>
1.18 cvs 7163: <dl>
1.30 cvs 7164: <dt><tt>Included</tt></dt>
7165: <dd>The element to be moved is the first element of the indicated type
7166: which is found inside the element to which the rule applies.</dd>
7167: <dt><tt>Referred</tt></dt>
7168: <dd>This keyword can only be used if the rule applies to a reference
7169: element. The element to be moved is either the element designated by the
7170: reference (if that element is of the specified type), or the first
7171: element of the desired type contained within the element designated by
7172: the reference.</dd>
7173: <dt>no keyword</dt>
7174: <dd>If the element to be moved is an associated element, defined in the <a
7175: href="#sectc314"><tt>ASSOC</tt> section</a> of the structure schema, all
7176: associated elements of this type which have not been translated yet are
7177: then translated. Certain elements may in fact have already been
7178: translated by a <tt>Get Referred</tt> rule.
7179: <p>If the element to be moved is not an associated element, the
7180: translator takes the first element of the indicated type from among the
7181: siblings of the rule's element. This is primarily used to change the
7182: order of the components of an aggregate.</p>
7183: </dd>
1.18 cvs 7184: </dl>
1.30 cvs 7185:
7186: <p>If the element to be moved is defined in a structure schema which is not
7187: the one which corresponds to the translation schema (in the case of an
7188: included object with a different schema), the type name of this element must
7189: be followed, between parentheses, by the name of the structure schema which
1.18 cvs 7190: defines it.</p>
7191: <pre> 'Get' [ RelPosition ] ElemID
1.6 cvs 7192: [ ExtStruct ]
7193: [ Position ] ';' /
7194: RelPosition = 'Included' / 'Referred' .
1.18 cvs 7195: ExtStruct = '(' ElemID ')' .</pre>
1.30 cvs 7196:
7197: <p>The <tt>Get</tt> rule has no effect if the element which it is supposed to
1.1 cvs 7198: move has already been translated. Thus, the element will not be duplicated.
7199: It is generally best to associate the rule with the first element which will
7200: be encountered by the translator in its traversal of the document. Suppose an
1.18 cvs 7201: aggregate has two elements <tt>A</tt> and <tt>B</tt>, with <tt>A</tt>
1.1 cvs 7202: appearing first in the logical structure. To permute these two elements, a
1.18 cvs 7203: <tt>Get B before</tt> rule should be associated with the <tt>A</tt> element
7204: type, not the inverse. Similarly, a rule of the form <tt>Get Included X
7205: After</tt>, even though syntactically correct, makes no sense since, by the
1.1 cvs 7206: time it will be applied, after the translation of the contents of the element
1.18 cvs 7207: to which it is attached, the <tt>X</tt> element will already have been
7208: translated.</p>
1.30 cvs 7209:
7210: <p>The <tt>Get</tt> rule is the only way to obtain the translation of the
1.1 cvs 7211: associated elements. In fact, the translator only traverses the primary tree
7212: of the document and thus does not translate the associated elements, except
1.18 cvs 7213: when the translation is explicitly required by a <tt>Get Referred Type</tt> or
7214: <tt>Get Type</tt> rule where <tt>Type</tt> is an associated element type.</p>
1.30 cvs 7215:
1.18 cvs 7216: <blockquote class="example">
1.30 cvs 7217: <p><strong>Example:</strong></p>
7218:
7219: <p>The structure schema defined figures as associated element which are
7220: composed of some content and a caption. Moreover, it is possible to make
7221: references to figures, using elements of the <tt>RefFigure</tt> type:</p>
7222: <pre> ...
1.1 cvs 7223: RefFigure = REFERENCE(Figure);
7224: ASSOC
1.6 cvs 7225: Figure = BEGIN
7226: Content = NATURE;
7227: Caption = Text;
7228: END;
1.18 cvs 7229: ...</pre>
1.30 cvs 7230:
7231: <p>Suppose it would be useful to make a figure appear in the translated
7232: document at the place in the text where the first reference to the figure is
7233: made. If some figures are not referenced, then they would appear at the end
7234: of the document. Also, each figure's caption should appear before the
7235: content. The following rules in the translation schema will produce this
7236: result:</p>
7237: <pre>Article : BEGIN
1.1 cvs 7238: ...
7239: Get Figures After;
7240: END;
7241: RefFigure : BEGIN
7242: If FirstRef Get Referred Figure;
7243: ...
7244: END;
7245: Content : BEGIN
7246: Get Caption Before;
7247: ...
1.18 cvs 7248: END;</pre>
7249: </blockquote>
7250: </div>
7251:
7252: <div class="subsection">
1.30 cvs 7253: <h3><a name="sectc5215">The <tt>Copy</tt> rule</a></h3>
1.18 cvs 7254:
1.30 cvs 7255: <p>Like the <tt>Get</tt> rule, the <tt>Copy</tt> rule generates the
7256: translation of a specified element, but it acts even if the element has
7257: already been translated and it allows to copy it or to translate it later.
7258: Both rules have the same syntax.</p>
1.18 cvs 7259: <pre> 'Copy' [ RelPosition ] ElemID
7260: [ ExtStruct ] [ Position ] ';'</pre>
7261: </div>
7262:
7263: <div class="subsection">
1.30 cvs 7264: <h3><a name="sectc5216">The <tt>Use</tt> rule</a></h3>
1.18 cvs 7265:
1.30 cvs 7266: <p>The <tt>Use</tt> rule specifies the translation schema to be applied to
1.1 cvs 7267: objects of a certain class that are part of the document. This rule only
7268: appears in the rules for the root element of the document (the first type
1.18 cvs 7269: defined after the <tt>STRUCT</tt> keyword in the structure schema) or the
1.1 cvs 7270: rules of an element defined by an external structure (by another structure
1.18 cvs 7271: schema). Also, the <tt>Use</tt> rule cannot be conditional.</p>
1.30 cvs 7272:
7273: <p>If the rule is applied to an element defined by an external structure, the
1.18 cvs 7274: <tt>Use</tt> keyword is simply followed by the name of the translation schema
1.1 cvs 7275: to be used for element constructed according to that external structure. If
7276: the rule is applied to the document's root element, it is formed by the
1.18 cvs 7277: <tt>Use</tt> keyword followed by the translation schema's name, the
7278: <tt>For</tt> keyword and the name of the external structure to which the
7279: indicated translation schema should be applied.</p>
7280: <pre> 'Use' TrSchema [ 'For' ElemID ] ';'
7281: TrSchema = NAME .</pre>
1.30 cvs 7282:
7283: <p>If no <tt>Use</tt> rule defines the translation schema to be used for an
1.1 cvs 7284: external structure which appears in a document, the translator asks the user,
7285: during the translation process, which schema should be used. Thus, it is not
1.18 cvs 7286: necessary to give the translation schema a <tt>Use</tt> rule for every
1.1 cvs 7287: external structure used, especially when the choice of translation schemas is
1.18 cvs 7288: to be left to the user.</p>
1.30 cvs 7289:
7290: <p>Notice: if the translator is launched by the editor (by the ``Save as''
1.18 cvs 7291: command), prompts are not displayed.</p>
1.30 cvs 7292:
1.18 cvs 7293: <blockquote class="example">
1.30 cvs 7294: <p><strong>Example:</strong></p>
7295:
7296: <p>The <tt>Article</tt> structure schema uses the <tt>Formula</tt> external
7297: structure, defined by another structure schema, for mathematical
7298: formulas:</p>
7299: <pre>STRUCTURE Article;
1.1 cvs 7300: ...
7301: STRUCT
7302: Article = ...
7303: ...
7304: Formula_in_text = Formula;
7305: Isolated_formula = Formula;
7306: ...
1.18 cvs 7307: END</pre>
1.30 cvs 7308:
7309: <p>Suppose that it would be useful to use the <tt>FormulaT</tt> translation
7310: schema for the formulas of an article. This can be expressed in two
7311: different ways in the <tt>Article</tt> class translation schema, using the
7312: rules:</p>
7313: <pre>RULES
1.1 cvs 7314: Article :
1.18 cvs 7315: Use FormulaT for Formula;</pre>
1.30 cvs 7316:
7317: <p>or:</p>
7318: <pre>RULES
1.1 cvs 7319: ...
7320: Formula :
1.18 cvs 7321: Use FormulaT;</pre>
7322: </blockquote>
7323: </div>
7324:
7325: <div class="subsection">
1.30 cvs 7326: <h3><a name="sectc5217">The <tt>Remove</tt> rule</a></h3>
1.18 cvs 7327:
1.30 cvs 7328: <p>The <tt>Remove</tt> rule indicates that nothing should be generated, in the
1.1 cvs 7329: translated document, for the content of the element to which the rule applies.
7330: The content of that element is simply ignored by the translator. This does
7331: not prevent the generation of text for the element itself, using the
1.18 cvs 7332: <tt>Create</tt> or <tt>Include</tt> rules, for example.</p>
1.30 cvs 7333:
7334: <p>The <tt>Remove</tt> rule is simply written with the <tt>Remove</tt>
7335: keyword. It is terminated, like all rules, by a semicolon.</p>
1.18 cvs 7336: <pre> 'Remove' ';'</pre>
7337: </div>
7338:
7339: <div class="subsection">
1.31 cvs 7340: <h3><a name="sectc5217a">The <tt>Ignore</tt> rule</a></h3>
7341:
7342: <p>The <tt>Ignore</tt> rule indicates that nothing should be generated, in the
7343: translated document, for the element to which the rule applies. The whole
1.32 cvs 7344: element is simply ignored by the translator.</p>
1.31 cvs 7345:
7346: <p>The <tt>Ignore</tt> rule is simply written with the <tt>Ignore</tt>
7347: keyword. It is terminated, like all rules, by a semicolon.</p>
7348: <pre> 'Ignore' ';'</pre>
7349: </div>
7350:
7351: <div class="subsection">
1.30 cvs 7352: <h3><a name="sectc5218">The <tt>NoTranslation</tt> rule</a></h3>
1.18 cvs 7353:
1.30 cvs 7354: <p>The <tt>NoTranslation</tt> rule indicates to the translator that it must
7355: not translate the content of the leaves of the element to which it applies. In
1.18 cvs 7356: contrast to the <tt>Remove</tt> rule, it does not suppress the content of the
1.1 cvs 7357: element, but it inhibits the translation of character strings, symbols, and
7358: graphical elements contained in the element. These are retrieved so that
1.18 cvs 7359: after the translation of the document, the rules of the <a
7360: href="#sectc5225"><tt>TEXTTRANSLATE</tt>, <tt>SYMBTRANSLATE</tt> and
7361: <tt>GRAPHTRANSLATE</tt> sections</a> will not be applied to them.</p>
1.30 cvs 7362:
7363: <p>The <tt>NoTranslation</tt> rule is written with the <tt>NoTranslation</tt>
1.18 cvs 7364: keyword followed by a semicolon.</p>
7365: <pre> 'NoTranslation' ';'</pre>
7366: </div>
7367:
7368: <div class="subsection">
1.30 cvs 7369: <h3><a name="sectc5219">The <tt>NoLineBreak</tt> rule</a></h3>
1.18 cvs 7370:
1.30 cvs 7371: <p>The <tt>NoLineBreak</tt> rule indicates to the translator that it must not
1.1 cvs 7372: generate additional line breaks in the output produced for the element to
1.18 cvs 7373: which it applies. This is as if it was an <a href="#sectc522">instruction
7374: <tt>LINELENGTH 0;</tt></a> at the beginning of the translation schema, but
7375: only for the current element.</p>
1.30 cvs 7376:
7377: <p>The <tt>NoLineBreak</tt> rule is written with the <tt>NoLineBreak</tt>
7378: keyword followed by a semicolon.</p>
1.18 cvs 7379: <pre> 'NoLineBreak' ';'</pre>
7380: </div>
1.1 cvs 7381:
1.18 cvs 7382: <div class="subsection">
1.30 cvs 7383: <h3><a name="sectc5220">The <tt>ChangeMainFile</tt> rule</a></h3>
1.1 cvs 7384:
1.30 cvs 7385: <p>When the translation program starts, it opens a main output file, whose
7386: name is given as a parameter of the translator. All <a
1.18 cvs 7387: href="#sectc5210"><tt>Create</tt> rules</a> without explicit indication of the
7388: output file write sequentially in this file. When a <tt>ChangeMainFile</tt>
7389: rule is executed, the main output file is closed and it is replaced by a new
7390: one, whose name is specified in the <tt>ChangeMainFile</tt> rule. The
7391: <tt>Create</tt> rules without indication of the output file that are then
7392: executed write in this new file. Several <tt>ChangeMainFile</tt> rules can be
7393: executed during the same translation, for dividing the main output into
7394: several files.</p>
1.30 cvs 7395:
7396: <p>This rule is written with the <tt>ChangeMainFile</tt> keyword followed by
7397: the name of a variable that specifies the name of the new main file. The
7398: keyword <tt>Before</tt> or <tt>After</tt> can be placed at the end of the rule
7399: to specify whether the operation should be performed before or after
7400: translation of the rule's element (the default is before). This rule, like all
7401: translation rules, is terminated by a semicolon.</p>
1.18 cvs 7402: <pre> 'ChangeMainFile' VarID [ Position ] ';'</pre>
1.30 cvs 7403:
1.18 cvs 7404: <blockquote class="example">
1.30 cvs 7405: <p><strong>Example:</strong></p>
7406:
7407: <p>To generate the translation of each section in a different file, the
7408: following rule can be associated with type <tt>Section</tt>. That rule uses
7409: the <a href="#varoutputfile"><tt>VarOutpuFile</tt> variable</a> defined
7410: above.</p>
7411: <pre> Section:
1.18 cvs 7412: ChangeMainFile VarOutpuFile Before;</pre>
1.30 cvs 7413:
7414: <p>If <tt>output.txt</tt> is the name of the output file specified when
7415: starting the translation program, translated sections are written in files
7416: <tt>output1.txt</tt>, <tt>output2.txt</tt>, etc.</p>
1.18 cvs 7417: </blockquote>
7418: </div>
1.1 cvs 7419:
1.18 cvs 7420: <div class="subsection">
1.30 cvs 7421: <h3><a name="sectc5220a">The <tt>RemoveFile</tt> rule</a></h3>
1.14 cvs 7422:
1.30 cvs 7423: <p>Files may be used for storing temporary data that are no longer needed when
1.18 cvs 7424: the translation of a document is complete. These files may be removed by the
7425: <tt>RemoveFile</tt> rule.</p>
1.30 cvs 7426:
7427: <p>This rule is written with the <tt>RemoveFile</tt> keyword followed by the
7428: name of a variable that specifies the name of the file to be removed. The
7429: keyword <tt>Before</tt> or <tt>After</tt> can be placed at the end of the rule
7430: to specify whether the operation should be performed before or after
7431: translation of the rule's element (the default is before). This rule, like
7432: all translation rules, is terminated by a semicolon.</p>
1.18 cvs 7433: <pre> 'RemoveFile' VarID [ Position ] ';'</pre>
7434: </div>
7435:
7436: <div class="subsection">
1.30 cvs 7437: <h3><a name="sectc5221">The <tt>Set</tt> and <tt>Add</tt> rules</a></h3>
1.18 cvs 7438:
1.30 cvs 7439: <p>The <tt>Set</tt> and <tt>Add</tt> rules are used for modifying the value of
1.18 cvs 7440: counters that have no <a href="#sectc524">counting function</a>. Only this
7441: type of counter can be used in the <tt>Set</tt> and <tt>Add</tt> rules.</p>
1.30 cvs 7442:
7443: <p>Both rules have the same syntax: after the keyword <tt>Set</tt> or
1.18 cvs 7444: <tt>Add</tt> appear the counter name and the value to assign to the counter
7445: (<tt>Set</tt> rule) or the value to be added to the counter (<tt>Add</tt>
7446: rule). The keyword <tt>Before</tt> or <tt>After</tt> can follow that value to
1.1 cvs 7447: indicate when the rule must be applied: before or after the element's content
1.18 cvs 7448: is translated. By default, <tt>Before</tt> is assumed. A semicolon terminates
7449: the rule.</p>
7450: <pre> 'Set' CounterID InitValue [ Position ] ';' /
7451: 'Add' CounterID Increment [ Position ] ';'</pre>
7452: </div>
7453:
7454: <div class="subsection">
1.30 cvs 7455: <h3><a name="sectc5221a">The <tt>Indent</tt> rule</a></h3>
1.18 cvs 7456:
1.30 cvs 7457: <p>The <tt>Indent</tt> rule is used to modify the value of text indentation in
1.18 cvs 7458: the output files.</p>
1.30 cvs 7459:
7460: <p>Each time the translator creates a new line in an output file, it generates
7461: a variable number of space characters at the beginning of the new line. By
1.25 cvs 7462: default, the number of these characters (the indentation value) is 0. It can
7463: be changed with the <tt>Indent</tt> rule.</p>
1.30 cvs 7464:
7465: <p>In its simple form, the rule begins with the <tt>Indent</tt> keyword,
1.25 cvs 7466: followed by the indentation sign (optional) and value and a keyword
1.30 cvs 7467: <tt>Before</tt> or <tt>After</tt> indicating that the indentation should be
7468: changed <a href="#sectc5222">before or after</a> the element's content is
7469: generated. If the position is not indicated, the indentation is changed
1.25 cvs 7470: before the element's content is generated. This rule, like all translation
7471: rules, is terminated by a semicolon.</p>
1.30 cvs 7472:
7473: <p>The indentation value is indicated by an integer, which is the number of
7474: space characters to be generated at the beginning of each new line. A sign
1.18 cvs 7475: (<tt>+</tt> or <tt>-</tt>) can appear before the integer to indicate that the
7476: value is relative: the current value of indentation is incremented (if sign is
7477: <tt>+</tt>) or decremented (if sign is <tt>-</tt>) by the specified value.</p>
1.30 cvs 7478:
7479: <p>Keyword <tt>Suspend</tt> or <tt>Resume</tt> can appear instead of the
1.25 cvs 7480: (possibly signed) identation value. <tt>Suspend</tt> means that the new
1.30 cvs 7481: indentation value to be used is zero until another <tt>Indent</tt> rule is
7482: executed and changes the indentation value. <tt>Resume</tt> means that the
7483: indentation value that was used before the last <tt>Indent Suspend</tt> was
7484: executed becomes the new value. Only one <tt>Suspend</tt> can be used before
7485: a <tt>Resume</tt>; <tt>Supend</tt>-<tt>Resume</tt> pairs can not be
7486: nested.</p>
7487:
7488: <p>Like the <a href="#sectc5210"><tt>Create</tt> rule</a>, the <tt>Indent</tt>
1.18 cvs 7489: keyword can be followed by the <tt>IN</tt> keyword and by the name of a <a
7490: href="#sectc526">variable</a>. This means that the rule must not change
1.10 cvs 7491: indentation in the main output file, but in the file whose name is specified
7492: by the variable (by default, indentation is changed in the main output
1.18 cvs 7493: file).</p>
1.25 cvs 7494: <pre> 'Indent' [ 'IN' VarID ] Indent [ Position ] ';' .
1.10 cvs 7495:
1.25 cvs 7496: Indent = 'Suspend' / 'Resume' / [ IndentSign ] IndentValue .
1.10 cvs 7497: IndentSign = '+' / '-' .
1.18 cvs 7498: IndentValue = NUMBER .</pre>
7499: </div>
1.10 cvs 7500:
1.18 cvs 7501: <div class="subsection">
1.30 cvs 7502: <h3><a name="sectc5222">Rule application order</a></h3>
1.1 cvs 7503:
1.30 cvs 7504: <p>The translator translates the elements which comprise the document in the
1.18 cvs 7505: order induced by the tree structure, except when the <tt>Get</tt> rule is used
1.1 cvs 7506: to change the order of translation. For each element, the translator first
7507: applies the rules specified for the element's type that must be applied before
1.18 cvs 7508: translation of the element's content (rules ending with the <tt>Before</tt>
1.1 cvs 7509: keyword or which have no position keyword). If several rules meet these
7510: criteria, the translator applies them in the order in where they appear in the
1.18 cvs 7511: translation schema.</p>
1.30 cvs 7512:
7513: <p>It then applies all <a href="#sectc5223">rules for the attributes</a> which
1.1 cvs 7514: the element has and which must be applied before the translation of the
1.18 cvs 7515: element's content (rules ending with the <tt>Before</tt> keyword or which have
1.1 cvs 7516: no position keyword). For one attribute value, the translator applies the
1.18 cvs 7517: rules in the order in which they are defined in the translation schema.</p>
1.30 cvs 7518:
7519: <p>The same procedure is followed with translation rules for specific
1.18 cvs 7520: presentations.</p>
1.30 cvs 7521:
1.31 cvs 7522: <p>Next, the element's content is translated, as long as a <tt>Remove</tt> or
7523: <code>Ignore</code> rule does not apply.</p>
1.30 cvs 7524:
7525: <p>In the next step, the translator applies rules for the specific
7526: presentation of the element that are to be applied after translation of the
7527: content (rules which end with the <tt>After</tt> keyword). The rules for each
7528: type of presentation rule or each value are applied in the order in which the
1.18 cvs 7529: translation appear in the schema.</p>
1.30 cvs 7530:
7531: <p>Then, the same procedure is followed for translation rules for attributes
7532: of the element.</p>
7533:
7534: <p>Finally, the translator applies rules for the element which must be applied
1.1 cvs 7535: after translation of the element's content. These rules are applied in the
7536: order that they appear in the translation schema. When the translation of an
7537: element is done, the translator procedes to translate the following
1.18 cvs 7538: element.</p>
1.30 cvs 7539:
7540: <p>This order can be changed with the <tt>Attributes</tt> and
1.18 cvs 7541: <tt>Presentation</tt> options of the <a href="#sectc5210"><tt>Create</tt>
7542: rule</a>.</p>
7543: </div>
1.1 cvs 7544:
1.18 cvs 7545: <div class="subsection">
1.30 cvs 7546: <h3><a name="sectc5223">Translation of logical attributes</a></h3>
1.1 cvs 7547:
1.30 cvs 7548: <p>After the rules for the element types, the translation schema defines rules
1.18 cvs 7549: for attribute values. This section begins with the <tt>ATTRIBUTES</tt>
1.1 cvs 7550: keyword and is composed of a sequence of rule blocks each preceded by an
1.18 cvs 7551: attribute name and an optional value or value range.</p>
1.30 cvs 7552:
7553: <p>If the attribute's name appears alone before the rule block, the rule are
1.1 cvs 7554: applied to all element which have the attribute, no matter what value the
7555: attribute has. In this case, the attribute name is followed by a colon before
1.18 cvs 7556: the beginning of the rule block.</p>
1.30 cvs 7557:
7558: <p>The attribute's name can be followed by the name of an element type between
1.1 cvs 7559: parentheses. This says, as in presentation schemas, that the rule block which
7560: follows applies not to the element which has the attribute, but to its
1.18 cvs 7561: descendants of the type indicated between the parentheses.</p>
1.30 cvs 7562:
7563: <p>If values are given after the attribute name (or after the name of the
7564: element type), the rules are applied only when the attribute has the indicated
7565: values. The same attribute can appear several times, with different values and
1.1 cvs 7566: different translation rules. Attribute values are indicated in the same way
1.18 cvs 7567: as in <a href="#sectc528">conditions</a> and are followed by a colon before
7568: the block of rules.</p>
1.30 cvs 7569:
7570: <p>The rule block associated with an attribute is either a simple rule or a
1.18 cvs 7571: sequence of rules delimited by the <tt>BEGIN</tt> and <tt>END</tt> keywords.
7572: Note that rules associated with attribute values cannot be conditional.</p>
1.30 cvs 7573:
7574: <p>Translation rules are not required for all attributes (or their values)
1.1 cvs 7575: defined in a structure schema. Only those attributes for which a particular
7576: action must be performed by the translator must have such rules. The rules
1.18 cvs 7577: that can be used are those described above, from <a
7578: href="#sectc5210"><tt>Create</tt></a> to <a
7579: href="#sectc5218"><tt>NoTranslation</tt></a>.</p>
1.30 cvs 7580: <pre> AttrSeq = TransAttr < TransAttr > .
1.1 cvs 7581: TransAttr = AttrID [ '(' ElemID ')' ]
7582: [ RelatAttr ] ':' RuleSeq .
7583: AttrID = NAME .
1.18 cvs 7584: ElemID = NAME .</pre>
1.30 cvs 7585:
1.18 cvs 7586: <blockquote class="example">
1.30 cvs 7587: <p><strong>Example:</strong></p>
7588:
7589: <p>The structure defined the ``Language'' attribute which can take the
7590: values ``French'' and ``English''. To have the French parts of the original
7591: document removed and prevent the translation of the leaves of the English
7592: parts, the following rules would be used:</p>
7593: <pre>ATTRIBUTES
1.1 cvs 7594: Language=French :
7595: Remove;
7596: Language=English :
1.18 cvs 7597: NoTranslation;</pre>
7598: </blockquote>
7599: </div>
1.1 cvs 7600:
1.18 cvs 7601: <div class="subsection">
1.30 cvs 7602: <h3><a name="sectc5224">Translation of specific presentations</a></h3>
1.1 cvs 7603:
1.30 cvs 7604: <p>After the rules for attributes, the translation schema defines rules for
7605: the specific presentation. This section begins with the <tt>PRESENTATION</tt>
1.1 cvs 7606: keyword and is composed of a sequence of translation rule blocks each preceded
7607: by a presentation rule name, optionally accompanied by a part which depends on
1.18 cvs 7608: the particular presentation rule.</p>
1.30 cvs 7609:
7610: <p>Each of these translation rule blocks is applied when the translator
7611: operates on an element which has a specific presentation rule of the type
7612: indicated at the head of the block. Depending on the type of the specific
7613: presentation rule, it is possible to specify values of the presentation rule
7614: for which the translation rule block should be applied.</p>
7615:
7616: <p>There are three categories of the presentation rules:</p>
7617: <ul>
7618: <li>rules taking numeric values: <tt>Size</tt>, <tt>Indent</tt>,
7619: <tt>LineSpacing</tt>, <tt>LineWeight</tt>,</li>
7620: <li>rules whose values are taken from a predefined list (i.e. whose type is
7621: an enumeration): <tt>Adjust</tt>, <tt>Justify</tt>, <tt>Hyphenate,/TT>,
7622: <tt>Style</tt>, <tt>Weight</tt>, <tt>Font</tt>, <tt>UnderLine</tt>,
7623: <tt>Thickness</tt>, <tt>LineStyle</tt>,</tt></li>
7624: <li>rules whose value is a name: <tt>FillPattern</tt>, <tt>Background</tt>,
7625: <tt>Foreground</tt>.</li>
1.18 cvs 7626: </ul>
1.30 cvs 7627:
7628: <p>For presentation rules of the first category, the values which provoke
1.1 cvs 7629: application of the translation rules are indicated in the same manner as for
1.18 cvs 7630: <a href="#relattr">numeric attributes</a>. This can be either a unique value
1.1 cvs 7631: or range of values. For a unique value, the value (an integer) is simply
7632: preceded by an equals sign. Value ranges can be specified in one of three
1.18 cvs 7633: ways:</p>
7634: <ul>
1.30 cvs 7635: <li>all values less than a given value (this value is preceded by a ``less
7636: than'' sign '<tt><</tt>'),</li>
7637: <li>all values greater than a given value (this value is preceded by a`
7638: `greater than'' sign '<tt>></tt>'),</li>
7639: <li>all values falling in an interval, bounds included. The range of values
7640: is then specified <tt>IN [</tt>Minimum<tt>..</tt>Maximum<tt>]</tt>, where
7641: Minimum and Maximum are integers.</li>
1.18 cvs 7642: </ul>
1.30 cvs 7643:
7644: <p>All numeric values can be negative, in which case the integer is preceded
7645: by a minus sign. All values must be given in typographers points.</p>
7646:
7647: <p>For presentation rules whose values are taken from a predefined list, the
1.1 cvs 7648: value which provokes application of the translation rules is simply indicated
1.18 cvs 7649: by the equals sign followed by the name of the value.</p>
1.30 cvs 7650:
7651: <p>For presentation rules whose values are names, the value which provokes the
1.1 cvs 7652: application of translation rules is simply indicated by the equals sign
7653: followed by the name of the value. The names of the fill patterns (the
1.18 cvs 7654: <tt>FillPattern</tt> rule) and of the colors (the <tt>Foreground</tt> and
7655: <tt>Background</tt> rules) used in Thot are the same as in the P language.</p>
1.30 cvs 7656: <pre> PresSeq = PresTrans < PresTrans > .
1.1 cvs 7657: PresTrans = PresRule ':' RuleSeq .
7658: PresRule = 'Size' [ PresRelation ] /
7659: 'Indent' [ PresRelation ] /
7660: 'LineSpacing' [ PresRelation ] /
7661: 'Adjust' [ '=' AdjustVal ] /
7662: 'Justify' [ '=' BoolVal ] /
7663: 'Hyphenate' [ '=' BoolVal ] /
7664: 'Style' [ '=' StyleVal ] /
1.24 cvs 7665: 'Weight' [ '=' WeightVal ] /
1.1 cvs 7666: 'Font' [ '=' FontVal ] /
7667: 'UnderLine' [ '=' UnderLineVal ] /
7668: 'Thickness' [ '=' ThicknessVal ] /
7669: 'LineStyle' [ '=' LineStyleVal ] /
7670: 'LineWeight' [ PresRelation ] /
7671: 'FillPattern' [ '=' Pattern ] /
7672: 'Background' [ '=' Color ] /
7673: 'Foreground' [ '=' Color ] .
7674:
7675: PresRelation = '=' PresValue /
1.30 cvs 7676: '>' [ '-' ] PresMinimum /
1.1 cvs 7677: '<' [ '-' ] PresMaximum /
7678: 'IN' '[' [ '-' ] PresIntervalMin '..'
7679: [ '-' ] PresIntervalMax ']' .
7680: AdjustVal = 'Left' / 'Right' / 'VMiddle' /
7681: 'LeftWithDots' .
7682: BoolVal = 'Yes' / 'No' .
1.24 cvs 7683: StyleVal = 'Roman' / 'Italics' / 'Oblique' .
7684: WeightVal = 'Normal' / 'Bold' .
1.1 cvs 7685: FontVal = 'Times' / 'Helvetica' / 'Courier' .
7686: UnderLineVal = 'NoUnderline' / 'UnderLined' /
7687: 'OverLined' / 'CrossedOut' .
7688: ThicknessVal = 'Thick' / 'Thin' .
1.6 cvs 7689: LineStyleVal = 'Solid' / 'Dashed' / 'Dotted' .
1.1 cvs 7690: Pattern = NAME .
7691: Color = NAME .
7692: PresMinimum = NUMBER .
7693: PresMaximum = NUMBER .
7694: PresIntervalMin= NUMBER .
7695: PresIntervalMax= NUMBER .
7696: PresValue = [ '-' ] PresVal .
1.18 cvs 7697: PresVal = NUMBER .</pre>
1.30 cvs 7698:
7699: <p>The <a name="prestransl">translation rules associated with specific
1.18 cvs 7700: presentation rules</a> can use the value of the specific presentation rule
1.1 cvs 7701: that causes them to be applied. This behavior is designated by the keyword
1.18 cvs 7702: <tt>Value</tt>. For numerically-valued presentation rules, the numeric value
1.1 cvs 7703: is produced. For other presentation rules, the name of the value is
1.18 cvs 7704: produced.</p>
1.30 cvs 7705:
7706: <p>It should be noted that modifications to the layout of the document's
7707: elements that are made using the combination of the control key and a mouse
7708: button will have no effect on the translation of the document.</p>
7709:
7710: <blockquote class="example">
7711: <p><strong>Example:</strong></p>
7712:
7713: <p>Suppose that it is desirable to use the same font sizes as in the
7714: specific presentation, but the font size must be between 10 and 18
7715: typographer's points. If font size is set in the translated document by the
7716: string <tt>pointsize=n</tt> where <tt>n</tt> is the font size in
7717: typographer's points then the following rules will suffice:</p>
7718: <pre>PRESENTATION
1.1 cvs 7719: Size < 10 :
7720: Create 'pointsize=10';
7721: Size in [10..18] :
7722: BEGIN
7723: Create 'pointsize=';
7724: Create Value;
7725: END;
1.30 cvs 7726: Size > 18 :
1.18 cvs 7727: Create 'pointsize=18';</pre>
7728: </blockquote>
7729: </div>
1.1 cvs 7730:
1.18 cvs 7731: <div class="subsection">
1.30 cvs 7732: <h3><a name="sectc5225">Recoding of characters, symbols and graphics</a></h3>
1.1 cvs 7733:
1.30 cvs 7734: <p>The coding of characters, graphical elements and symbols as defined in Thot
1.1 cvs 7735: does not necessarily correspond to what is required by an application to which
7736: a Thot document must be exported. Because of this the translator can recode
7737: these terminal elements of the documents structure. The last sections of a
7738: translation schema are intended for this purpose, each specifying the recoding
1.18 cvs 7739: rules for one type of terminal element.</p>
1.30 cvs 7740:
7741: <p>The recoding rules for character strings are grouped by alphabets. There is
7742: a group of rules for each alphabet of the Thot document that must be
7743: translated. Each such group of rules begins with the <tt>TEXTTRANSLATE</tt>
7744: keyword, followed by the specification of the alphabet to translate and the
7745: recoding rules, between the <tt>BEGIN</tt> and <tt>END</tt> keywords unless
7746: there is only one recoding rule for the alphabet. The specification of the
7747: alphabet is not required: by default it is assumed to the Latin alphabet (the
7748: ISO Latin-1 character set).</p>
7749:
7750: <p>Each recoding rule is formed by a source string between apostrophes and a
1.1 cvs 7751: target string, also between apostrophes, the two strings being separated by
1.30 cvs 7752: the arrow symbol (<tt>-></tt>), formed by the ``minus'' and ``greater
7753: than'' characters. The rule is terminated by a semi-colon.</p>
1.18 cvs 7754: <pre> TextTransSeq = [ Alphabet ] TransSeq .
1.1 cvs 7755: Alphabet = NAME .
1.30 cvs 7756: TransSeq ='BEGIN' < Translation > 'END' ';' /
1.1 cvs 7757: Translation .
1.30 cvs 7758: Translation = Source [ '->' Target ] ';' .
1.1 cvs 7759: Source = STRING .
1.18 cvs 7760: Target = STRING .</pre>
1.30 cvs 7761:
7762: <p>One such rule signifies that when the source string appears in a text leaf
7763: of the document being translated, the translator must replace it, in the
1.1 cvs 7764: translated document, with the target string. The source string and the target
7765: string can have different lengths and the target string can be empty. In this
7766: last case, the translator simply suppresses every occurrence of the source
1.18 cvs 7767: string in the translated document.</p>
1.30 cvs 7768:
7769: <p>For a given alphabet, the order of the rules is not important and has no
1.1 cvs 7770: significance because the T language compiler reorders the rules in ways that
7771: speed up the translator's work. The total number of recoding rules is limited
1.18 cvs 7772: by the compiler as is the maximum length of the source and target strings.</p>
1.30 cvs 7773:
7774: <p>The recoding rules for symbols and graphical elements are written in the
7775: same manner as the recoding rules for character strings. They are preceded,
1.18 cvs 7776: respectively, by the <tt>SYMBTRANSLATE</tt> and <tt>GRAPHTRANSLATE</tt> and so
1.1 cvs 7777: not require a specification of the alphabet. Their source string is limited to
7778: one character, since, in Thot, each symbol and each graphical element is
7779: represented by a single character. The symbol and graphical element codes are
1.18 cvs 7780: defined along with the <a href="#sect7">non-standard character codes</a>.</p>
1.30 cvs 7781:
1.18 cvs 7782: <blockquote class="example">
1.30 cvs 7783: <p><strong>Example:</strong></p>
7784:
7785: <p>In a translation schema producing documents destined for use with the
7786: L<sup>A</sup>T<sub><big>E</big></sub>X formatter, the Latin characters``é''
7787: (octal code 351 in Thot) and ``č'' (octal code 350 in Thot) must be
7788: converted to their representation in
7789: L<sup>A</sup>T<sub><big>E</big></sub>X:</p>
7790: <pre>TEXTTRANSLATE Latin
1.1 cvs 7791: BEGIN
1.30 cvs 7792: '\350' -> '\`{e}'; { e grave }
7793: '\351' -> '\''{e}'; { e acute }
1.18 cvs 7794: END;</pre>
7795: </blockquote>
7796: </div>
7797: </div>
7798: <hr>
7799: </div>
1.1 cvs 7800:
1.18 cvs 7801: <div class="chapter">
1.30 cvs 7802: <h1><a name="sect6">Language grammars</a></h1>
1.1 cvs 7803:
1.30 cvs 7804: <p>This chapter gives the complete grammars of the languages of Thot. The
1.1 cvs 7805: grammars were presented and described in the preceding chapters, which also
7806: specify the semantics of the languages. This section gives only the
1.18 cvs 7807: syntax.</p>
1.1 cvs 7808:
1.18 cvs 7809: <div class="section">
1.30 cvs 7810: <h2><a name="sectb61">The M meta-language</a></h2>
1.1 cvs 7811:
1.30 cvs 7812: <p>The language grammars are all expressed in the same formalism, the M
1.18 cvs 7813: meta-language, which is defined in this section.</p>
7814: <pre>{ Any text between braces is a comment. }
1.30 cvs 7815: Grammar = Rule < Rule > 'END' .
7816: { The < and > signs indicate zero }
1.1 cvs 7817: { or more repetitions. }
7818: { END marks the end of the grammar. }
7819: Rule = Ident '=' RightPart '.' .
7820: { The period indicates the end of a rule }
7821: RightPart = RtTerminal / RtIntermed .
7822: { The slash indicates a choice }
7823: RtTerminal ='NAME' / 'STRING' / 'NUMBER' .
7824: { Right part of a terminal rule }
1.30 cvs 7825: RtIntermed = Possibility < '/' Possibility > .
1.1 cvs 7826: { Right part of an intermediate rule }
1.30 cvs 7827: Possibility = ElemOpt < ElemOpt > .
7828: ElemOpt = Element / '[' Element < Element > ']' /
7829: '<' Element < Element > '>' .
1.1 cvs 7830: { Brackets delimit optional parts }
7831: Element = Ident / KeyWord .
7832: Ident = NAME .
7833: { Identifier, sequence of characters
7834: KeyWord = STRING .
7835: { Character string delimited by apostrophes }
1.18 cvs 7836: END</pre>
7837: </div>
1.1 cvs 7838:
1.18 cvs 7839: <div class="section">
1.30 cvs 7840: <h2><a name="sectb62">The S language</a></h2>
1.1 cvs 7841:
1.30 cvs 7842: <p>The S language is used to write structure schemas, which contain the
7843: generic logical structures of document and object classes. It is described
7844: here in the M meta-language.</p>
1.18 cvs 7845: <pre>StructSchema = 'STRUCTURE' [ 'EXTENSION' ] ElemID ';'
1.1 cvs 7846: 'DEFPRES' PresID ';'
7847: [ 'ATTR' AttrSeq ]
7848: [ 'STRUCT' RulesSeq ]
7849: [ 'EXTENS' ExtensRuleSeq ]
7850: [ 'ASSOC' RulesSeq ]
7851: [ 'UNITS' RulesSeq ]
7852: [ 'EXPORT' SkeletonSeq ]
7853: [ 'EXCEPT' ExceptSeq ]
7854: 'END' .
7855:
7856: ElemID = NAME .
7857: PresID = NAME .
7858:
1.30 cvs 7859: AttrSeq = Attribute < Attribute > .
1.1 cvs 7860: Attribute = AttrID '=' AttrType ';' .
7861: AttrType = 'INTEGER' / 'TEXT' /
7862: 'REFERENCE' '(' RefType ')' /
7863: ValueSeq .
7864: RefType = 'ANY' /
7865: [ FirstSec ] ElemID [ ExtStruct ] .
1.30 cvs 7866: ValueSeq = AttrVal < ',' AttrVal > .
1.1 cvs 7867: AttrID = NAME .
7868: FirstSec = 'First' / 'Second' .
7869: ExtStruct = '(' ElemID ')' .
7870: AttrVal = NAME .
7871:
1.30 cvs 7872: RulesSeq = Rule < Rule > .
1.1 cvs 7873: Rule = ElemID [ LocAttrSeq ] '='
7874: DefWithAttr ';' .
7875: LocAttrSeq = '(' 'ATTR' LocalAttr
1.30 cvs 7876: < ';' LocalAttr > ')' .
1.1 cvs 7877: LocalAttr = [ '!' ] AttrID [ '=' AttrType ] .
7878: DefWithAttr = Definition
7879: [ '+' '(' ExtensionSeq ')' ]
7880: [ '-' '(' RestrictSeq ')' ]
7881: [ 'WITH' FixedAttrSeq ] .
1.30 cvs 7882: ExtensionSeq = ExtensionElem < ',' ExtensionElem > .
1.1 cvs 7883: ExtensionElem = ElemID / 'TEXT' / 'GRAPHICS' /
7884: 'SYMBOL' / 'PICTURE' .
1.30 cvs 7885: RestrictSeq = RestrictElem < ',' RestrictElem > .
1.1 cvs 7886: RestrictElem = ElemID / 'TEXT' / 'GRAPHICS' /
7887: 'SYMBOL' / 'PICTURE' .
1.30 cvs 7888: FixedAttrSeq = FixedAttr < ',' FixedAttr > .
1.1 cvs 7889: FixedAttr = AttrID [ FixedOrModifVal ] .
7890: FixedOrModifVal= [ '?' ] '=' FixedValue .
7891: FixedValue = [ '-' ] NumValue / TextValue / AttrVal .
7892: NumValue = NUMBER .
7893: TextValue = STRING .
7894:
7895: Definition = BaseType [ LocAttrSeq ] / Constr /
7896: Element .
7897: BaseType = 'TEXT' / 'GRAPHICS' / 'SYMBOL' /
7898: 'PICTURE' / 'UNIT' / 'NATURE' .
7899: Element = ElemID [ ExtOrDef ] .
7900: ExtOrDef = 'EXTERN' / 'INCLUDED' /
7901: [ LocAttrSeq ] '=' Definition .
7902:
7903: Constr = 'LIST' [ '[' min '..' max ']' ] 'OF'
7904: '(' DefWithAttr ')' /
7905: 'BEGIN' DefOptSeq 'END' /
7906: 'AGGREGATE' DefOptSeq 'END' /
7907: 'CASE' 'OF' DefSeq 'END' /
7908: 'REFERENCE' '(' RefType ')' /
7909: 'PAIR' .
7910:
7911: min = Integer / '*' .
7912: max = Integer / '*' .
7913: Integer = NUMBER .
7914:
1.30 cvs 7915: DefOptSeq = DefOpt ';' < DefOpt ';' > .
1.1 cvs 7916: DefOpt = [ '?' ] DefWithAttr .
7917:
1.30 cvs 7918: DefSeq = DefWithAttr ';' < DefWithAttr ';' > .
1.1 cvs 7919:
1.30 cvs 7920: SkeletonSeq = SkeletonElem < ',' SkeletonElem > ';' .
1.1 cvs 7921: SkeletonElem = ElemID [ 'WITH' Contents ] .
7922: Contents = 'Nothing' / ElemID [ ExtStruct ] .
7923:
1.30 cvs 7924: ExceptSeq = Except ';' < Except ';' > .
1.1 cvs 7925: Except = [ 'EXTERN' ] [ FirstSec ] ExcTypeOrAttr ':'
7926: ExcValSeq .
7927: ExcTypeOrAttr = ElemID / AttrID .
1.30 cvs 7928: ExcValSeq = ExcValue < ',' ExcValue > .
1.1 cvs 7929: ExcValue = 'NoCut' / 'NoCreate' /
7930: 'NoHMove' / 'NoVMove' / 'NoMove' /
7931: 'NoHResize' / 'NoVResize' / 'NoResize' /
1.18 cvs 7932: 'MoveResize' /
1.1 cvs 7933: 'NewWidth' / 'NewHeight' /
7934: 'NewHPos' / 'NewVPos' /
7935: 'Invisible' / 'NoSelect' /
7936: 'Hidden' / 'ActiveRef' /
7937: 'ImportLine' / 'ImportParagraph' /
1.9 cvs 7938: 'NoPaginate' / 'ParagraphBreak' /
7939: 'HighlightChildren' / 'ExtendedSelection' /
1.29 cvs 7940: 'ReturnCreateNL' / 'ReturnCreateWithin' .
1.1 cvs 7941:
1.30 cvs 7942: ExtensRuleSeq = ExtensRule ';' < ExtensRule ';' > .
1.1 cvs 7943: ExtensRule = RootOrElem [ LocAttrSeq ]
7944: [ '+' '(' ExtensionSeq ')' ]
7945: [ '-' '(' RestrictSeq ')' ]
7946: [ 'WITH' FixedAttrSeq ] .
7947: RootOrElem = 'Root' / ElemID .
7948:
1.18 cvs 7949: END</pre>
7950: </div>
1.1 cvs 7951:
1.18 cvs 7952: <div class="section">
1.30 cvs 7953: <h2><a name="sectb63">The P language</a></h2>
1.1 cvs 7954:
1.30 cvs 7955: <p>The P language is used to write presentation schemas, which define the
1.1 cvs 7956: graphical presentation rules to be applied to different classes of documents
1.18 cvs 7957: and objects. It is described here in the M meta-language.</p>
7958: <pre>PresSchema = 'PRESENTATION' ElemID ';'
1.1 cvs 7959: [ 'VIEWS' ViewSeq ]
7960: [ 'PRINT' PrintViewSeq ]
7961: [ 'COUNTERS' CounterSeq ]
7962: [ 'CONST' ConstSeq ]
7963: [ 'VAR' VarSeq ]
7964: [ 'DEFAULT' ViewRuleSeq ]
7965: [ 'BOXES' BoxSeq ]
7966: [ 'RULES' PresentSeq ]
7967: [ 'ATTRIBUTES' PresAttrSeq ]
7968: [ 'TRANSMIT' TransmitSeq ]
7969: 'END' .
7970:
7971: ElemID = NAME .
7972:
7973: ViewSeq = ViewDeclaration
1.30 cvs 7974: < ',' ViewDeclaration > ';' .
1.1 cvs 7975: ViewDeclaration = ViewID [ 'EXPORT' ] .
7976: ViewID = NAME .
7977:
1.30 cvs 7978: PrintViewSeq = PrintView < ',' PrintView > ';' .
1.1 cvs 7979: PrintView = ViewID / ElemID .
7980:
1.30 cvs 7981: CounterSeq = Counter < Counter > .
1.1 cvs 7982: Counter = CounterID ':' CounterFunc ';' .
7983: CounterID = NAME .
7984: CounterFunc = 'RANK' 'OF' TypeOrPage [ SLevelAsc ]
7985: [ 'INIT' AttrID ] [ 'REINIT' AttrID ] /
1.30 cvs 7986: SetFunction < SetFunction >
7987: AddFunction < AddFunction >
1.1 cvs 7988: [ 'INIT' AttrID ] /
1.16 cvs 7989: 'RLEVEL' 'OF' ElemID .
1.1 cvs 7990: SLevelAsc = [ '-' ] LevelAsc .
7991: LevelAsc = NUMBER .
7992: SetFunction = 'SET' CounterValue 'ON' TypeOrPage .
7993: AddFunction = 'ADD' CounterValue 'ON' TypeOrPage .
7994: TypeOrPage = 'Page' [ '(' ViewID ')' ] /
1.16 cvs 7995: [ '*' ] ElemID .
1.1 cvs 7996: CounterValue = NUMBER .
7997:
1.30 cvs 7998: ConstSeq = Const < Const > .
1.1 cvs 7999: Const = ConstID '=' ConstType ConstValue ';' .
8000: ConstID = NAME .
8001: ConstType = 'Text' [ Alphabet ] / 'Symbol' /
8002: 'Graphics' / 'Picture' .
8003: ConstValue = STRING .
8004: Alphabet = NAME .
8005:
1.30 cvs 8006: VarSeq = Variable < Variable > .
1.1 cvs 8007: Variable = VarID ':' FunctionSeq ';' .
8008: VarID = NAME .
1.30 cvs 8009: FunctionSeq = Function < Function > .
1.1 cvs 8010: Function = 'DATE' / 'FDATE' /
8011: 'DocName' / 'DirName' /
8012: 'ElemName' / 'AttributeName' /
8013: ConstID / ConstType ConstValue /
8014: AttrID /
8015: 'VALUE' '(' PageAttrCtr ','
8016: CounterStyle ')' .
8017: PageAttrCtr = 'PageNumber' [ '(' ViewID ')' ] /
8018: [ MinMax ] CounterID / AttrID .
8019: CounterStyle = 'Arabic' / 'LRoman' / 'URoman' /
8020: 'Uppercase' / 'Lowercase' .
8021: MinMax = 'MaxRangeVal' / 'MinRangeVal' .
8022:
1.30 cvs 8023: BoxSeq = Box < Box > .
1.1 cvs 8024: Box = 'FORWARD' BoxID ';' /
8025: BoxID ':' ViewRuleSeq .
8026: BoxID = NAME .
8027:
1.30 cvs 8028: PresentSeq = Present < Present > .
1.1 cvs 8029: Present = [ '*' ] [ FirstSec ] ElemID ':'
8030: ViewRuleSeq .
8031: FirstSec = 'First' / 'Second' .
8032:
1.30 cvs 8033: PresAttrSeq = PresAttr < PresAttr > .
1.1 cvs 8034: PresAttr = AttrID [ '(' [ FirstSec ] ElemID ')' ]
8035: [ AttrRelation ] ':' ViewRuleSeq .
8036: AttrID = NAME .
8037: AttrRelation = '=' AttrVal /
1.30 cvs 8038: '>' [ '-' ] MinValue /
1.1 cvs 8039: '<' [ '-' ] MaxValue /
8040: 'IN' '[' [ '-' ] LowerBound '..'
8041: [ '-' ] UpperBound ']' /
8042: 'GREATER' AttrID /
8043: 'EQUAL' AttrID /
8044: 'LESS' AttrID .
8045: AttrVal = [ '-' ] EqualNum / EqualText / AttrValue .
8046: MinValue = NUMBER .
8047: MaxValue = NUMBER .
8048: LowerBound = NUMBER .
8049: UpperBound = NUMBER.
8050: EqualNum = NUMBER .
8051: EqualText = STRING .
8052: AttrValue = NAME .
8053:
1.30 cvs 8054: ViewRuleSeq = 'BEGIN' < RulesAndCond > < ViewRules >
1.1 cvs 8055: 'END' ';' /
8056: ViewRules / CondRules / Rule .
8057: RulesAndCond = CondRules / Rule .
8058: ViewRules = 'IN' ViewID CondRuleSeq .
1.30 cvs 8059: CondRuleSeq = 'BEGIN' < RulesAndCond > 'END' ';' /
1.1 cvs 8060: CondRules / Rule .
1.30 cvs 8061: CondRules = CondRule < CondRule >
1.1 cvs 8062: [ 'Otherwise' RuleSeq ] .
8063: CondRule = 'IF' ConditionSeq RuleSeq .
1.30 cvs 8064: RulesSeq = 'BEGIN' Rule < Rule > 'END' ';' / Rule .
1.1 cvs 8065:
1.30 cvs 8066: ConditionSeq = Condition < 'AND' Condition > .
1.6 cvs 8067: Condition = [ 'NOT' ] [ 'Target' ] ConditionElem .
8068: ConditionElem = 'First' / 'Last' /
8069: [ 'Immediately' ] 'Within' [ NumParent ]
8070: ElemID [ ExtStruct ] /
8071: ElemID /
8072: 'Referred' / 'FirstRef' / 'LastRef' /
8073: 'ExternalRef' / 'InternalRef' / 'CopyRef' /
8074: 'AnyAttributes' / 'FirstAttr' / 'LastAttr' /
8075: 'UserPage' / 'StartPage' / 'ComputedPage' /
1.33 cvs 8076: 'Empty' / 'Root' /
1.6 cvs 8077: '(' [ MinMax ] CounterName CounterCond ')' /
8078: CondPage '(' CounterID ')' .
8079: NumParent = [ GreaterLess ] NParent .
1.30 cvs 8080: GreaterLess = '>' / '<' .
1.6 cvs 8081: NParent = NUMBER.
1.30 cvs 8082: CounterCond = '<' MaxCtrVal / '>' MinCtrVal /
1.6 cvs 8083: '=' EqCtrVal /
8084: 'IN' '[' ['-'] MinCtrBound '..'
8085: ['-'] MaxCtrBound ']' .
8086: PageCond = 'Even' / 'Odd' / 'One' .
8087: MaxCtrVal = NUMBER .
8088: MinCtrVal = NUMBER .
8089: EqCtrVal = NUMBER .
8090: MaxCtrBound = NUMBER .
8091: MinCtrBound = NUMBER .
1.1 cvs 8092:
1.34 ! cvs 8093: Rule = Property ';' / PresFunc ';' .
! 8094: Property = 'VertRef' ':' HorizPosition /
1.1 cvs 8095: 'HorizRef' ':' VertPosition /
8096: 'VertPos' ':' VPos /
8097: 'HorizPos' ':' HPos /
8098: 'Height' ':' Extent /
8099: 'Width' ':' Extent /
8100: 'VertOverflow' ':' Boolean /
8101: 'HorizOverflow' ':' Boolean /
1.26 cvs 8102: 'MarginTop' ':' MarginWidth /
8103: 'MarginRight' ':' MarginWidth /
8104: 'MarginBottom' ':' MarginWidth /
8105: 'MarginLeft' ':' MarginWidth /
8106: 'PaddingTop' ':' PaddingWidth /
8107: 'PaddingRight' ':' PaddingWidth /
8108: 'PaddingBottom' ':' PaddingWidth /
8109: 'PaddingLeft' ':' PaddingWidth /
8110: 'BorderTopWidth' ':' BorderWidth /
8111: 'BorderRightWidth' ':' BorderWidth /
8112: 'BorderBottomWidth' ':' BorderWidth /
8113: 'BorderLeftWidth' ':' BorderWidth /
8114: 'BorderTopColor' ':' BorderColor /
8115: 'BorderRightColor' ':' BorderColor /
8116: 'BorderBottomColor' ':' BorderColor /
8117: 'BorderLeftColor' ':' BorderColor /
8118: 'BorderTopStyle' ':' BorderStyle /
8119: 'BorderRightStyle' ':' BorderStyle /
8120: 'BorderBottomStyle' ':' BorderStyle /
8121: 'BorderLeftStyle' ':' BorderStyle .
1.1 cvs 8122: 'LineSpacing' ':' DistOrInherit /
8123: 'Indent' ':' DistOrInherit /
8124: 'Adjust' ':' AlignOrInherit /
8125: 'Justify' ':' BoolInherit /
8126: 'Hyphenate' ':' BoolInherit /
8127: 'PageBreak' ':' Boolean /
8128: 'LineBreak' ':' Boolean /
8129: 'InLine' ':' Boolean /
8130: 'NoBreak1' ':' AbsDist /
8131: 'NoBreak2' ':' AbsDist /
8132: 'Gather' ':' Boolean /
8133: 'Visibility' ':' NumberInherit /
8134: 'Size' ':' SizeInherit /
8135: 'Font' ':' NameInherit /
8136: 'Style' ':' StyleInherit /
1.23 cvs 8137: 'Weight' ':' WeightInherit /
1.1 cvs 8138: 'Underline' ':' UnderLineInherit /
8139: 'Thickness' ':' ThicknessInherit /
8140: 'Depth' ':' NumberInherit /
8141: 'LineStyle' ':' LineStyleInherit /
8142: 'LineWeight' ':' DistOrInherit /
8143: 'FillPattern' ':' NameInherit /
1.30 cvs 8144: 'Background' ':' Color /
8145: 'Foreground' ':' Color /
1.1 cvs 8146: 'Content' ':' VarConst .
8147: PresFunc = Creation '(' BoxID ')' /
8148: 'Line' /
8149: 'NoLine' /
8150: 'Page' '(' BoxID ')' /
1.13 cvs 8151: 'Copy' '(' BoxTypeToCopy ')' /
8152: 'ShowBox' /
1.18 cvs 8153: 'BackgroundPicture' ':' FileName /
8154: 'PictureMode' ':' PictMode .
1.1 cvs 8155:
8156: BoxTypeToCopy = BoxID [ ExtStruct ] /
8157: ElemID [ ExtStruct ] .
8158: ExtStruct = '(' ElemID ')' .
8159:
8160: Distance = [ Sign ] AbsDist .
8161: Sign = '+' / '-' .
8162: AbsDist = IntegerOrAttr [ '.' DecimalPart ]
8163: [ Unit ] .
8164: IntegerOrAttr = IntegerPart / AttrID .
8165: IntegerPart = NUMBER .
8166: DecimalPart = NUMBER .
8167: Unit = 'em' / 'ex' / 'cm' / 'mm' / 'in' / 'pt' /
8168: 'pc' / 'px' / '%' .
8169:
8170: HPos = 'nil' / VertAxis '=' HorizPosition
8171: [ 'UserSpecified' ] .
8172: VPos = 'nil' / HorizAxis '=' VertPosition
8173: [ 'UserSpecified' ] .
8174: VertAxis = 'Left' / 'VMiddle' / 'VRef' / 'Right' .
8175: HorizAxis = 'Top' / 'HMiddle' / 'HRef' / 'Bottom' .
8176:
1.6 cvs 8177: VertPosition = Reference '.' HorizAxis [ Distance ] .
8178: HorizPosition = Reference '.' VertAxis [ Distance ] .
8179: Reference = 'Enclosing' [ BoxTypeNot ] /
8180: 'Enclosed' [ BoxTypeNot ] /
8181: 'Previous' [ BoxTypeNot ] /
8182: 'Next' [ BoxTypeNot ] /
8183: 'Referred' [ BoxTypeNot ] /
8184: 'Creator' /
8185: 'Root' /
8186: '*' /
8187: BoxOrType .
8188: BoxOrType = BoxID /
8189: [ '*' ] [ FirstSec ] ElemID /
1.17 cvs 8190: 'AnyElem' / 'AnyBox' /
8191: 'ElemWithAttr' AttrID .
1.6 cvs 8192: BoxTypeNot = [ 'NOT' ] BoxOrType .
8193:
8194: Extent = Reference '.' HeightWidth
8195: [ Relation ] [ 'Min' ] /
8196: AbsDist [ 'UserSpecified' ] [ 'Min' ] /
8197: HPos / VPos .
8198: HeightWidth = 'Height' / 'Width' .
8199: Relation = '*' ExtentAttr '%' / Distance .
8200: ExtentAttr = ExtentVal / AttrID .
8201: ExtentVal = NUMBER .
1.26 cvs 8202:
8203: MarginWidth = InheritParent / 'Auto' / Distance .
8204: PaddingWidth = InheritParent / Distance .
8205: BorderWidth = InheritParent / 'Thin' / 'Medium' / 'Thick' / Distance .
8206: BorderColor = InheritParent / 'Transparent' / 'Foreground' /
8207: ColorName .
8208: BorderStyle = InheritParent /
8209: 'None' / 'Hidden' / 'Dotted' / 'Dashed' / 'Solid' /
8210: 'Double' / 'Groove' / 'Ridge' / 'Inset' / 'Outset' .
1.27 cvs 8211: InheritParent = 'Enclosing' '=' / 'Creator' '=' .
1.26 cvs 8212: ColorName = NAME .
1.6 cvs 8213:
8214: Inheritance = Kinship InheritedValue .
8215: Kinship = 'Enclosing' / 'GrandFather'/ 'Enclosed' /
8216: 'Previous' / 'Creator' .
8217: InheritedValue = '+' PosIntAttr [ 'Max' maximumA ] /
8218: '-' NegIntAttr [ 'Min' minimumA ] /
8219: '=' .
8220: PosIntAttr = PosInt / AttrID .
8221: PosInt = NUMBER .
8222: NegIntAttr = NegInt / AttrID .
8223: NegInt = NUMBER .
8224: maximumA = maximum / AttrID .
8225: maximum = NUMBER .
8226: minimumA = minimum / AttrID .
8227: minimum = NUMBER .
8228:
8229: AlignOrInherit = Kinship '=' / Alignment .
8230: Alignment = 'Left' / 'Right' / 'VMiddle' /
8231: 'LeftWithDots' .
1.1 cvs 8232:
1.6 cvs 8233: DistOrInherit = Kinship InheritedDist / Distance .
8234: InheritedDist = '=' / '+' AbsDist / '-' AbsDist .
1.1 cvs 8235:
1.6 cvs 8236: BoolInherit = Boolean / Kinship '=' .
8237: Boolean = 'Yes' / 'No' .
1.1 cvs 8238:
1.6 cvs 8239: NumberInherit = Integer / AttrID / Inheritance .
8240: Integer = NUMBER .
1.1 cvs 8241:
8242: LineStyleInherit= Kinship '=' / 'Solid' / 'Dashed' /
8243: 'Dotted' .
8244:
1.6 cvs 8245: SizeInherit = SizeAttr [ 'pt' ] / Kinship InheritedSize .
8246: InheritedSize = '+' SizeAttr [ 'pt' ]
8247: [ 'Max' MaxSizeAttr ] /
8248: '-' SizeAttr [ 'pt' ]
8249: [ 'Min' MinSizeAttr ] /
1.22 cvs 8250: '*' PercentSizeAttr '%' /
1.6 cvs 8251: '=' .
8252: SizeAttr = Size / AttrID .
8253: Size = NUMBER .
8254: MaxSizeAttr = MaxSize / AttrID .
8255: MaxSize = NUMBER .
8256: MinSizeAttr = MinSize / AttrID .
8257: MinSize = NUMBER .
1.22 cvs 8258: PercentSizeAttr = PercentSize / AttrID .
8259: PercentSize = NUMBER .
1.6 cvs 8260:
8261: NameInherit = Kinship '=' / FontName .
8262: FontName = NAME .
1.30 cvs 8263: Color = 'Transparent' / Kinship '=' / FontName .
1.6 cvs 8264: StyleInherit = Kinship '=' /
1.23 cvs 8265: 'Roman' / 'Italics' / 'Oblique' .
8266: WeightInherit = Kinship '=' /
8267: 'Normal' / 'Bold' .
1.1 cvs 8268: UnderLineInherit= Kinship '=' /
1.6 cvs 8269: 'NoUnderline' / 'Underlined' /
8270: 'Overlined' / 'CrossedOut' .
1.1 cvs 8271: ThicknessInherit= Kinship '=' / 'Thick' / 'Thin' .
1.13 cvs 8272:
8273: FileName = STRING .
8274: PictMode = 'NormalSize' / 'Scale' /
8275: 'RepeatXY' / 'RepeatX' / 'RepeatY' .
1.1 cvs 8276:
1.6 cvs 8277: VarConst = ConstID / ConstType ConstValue /
8278: VarID / '(' FunctionSeq ')' /
8279: ElemID .
8280:
8281: Creation = Create [ 'Repeated' ] .
8282: Create = 'CreateFirst' / 'CreateLast' /
8283: 'CreateBefore' / 'CreateAfter' /
8284: 'CreateEnclosing' .
8285:
1.30 cvs 8286: TransmitSeq = Transmit < Transmit > .
1.6 cvs 8287: Transmit = TypeOrCounter 'To' ExternAttr
8288: '(' ElemID ')' ';' .
8289: TypeOrCounter = CounterID / ElemID .
8290: ExternAttr = NAME .
1.1 cvs 8291:
1.18 cvs 8292: END</pre>
8293: </div>
1.1 cvs 8294:
1.18 cvs 8295: <div class="section">
8296: <h2><a name="sectb64">The T language</a></h2>
8297: <pre>TransSchema = 'TRANSLATION' ElemID ';'
1.1 cvs 8298: [ 'LINELENGTH' LineLength ';' ]
8299: [ 'LINEEND' CHARACTER ';' ]
8300: [ 'LINEENDINSERT' STRING ';' ]
8301: [ 'BUFFERS' BufferSeq ]
8302: [ 'COUNTERS' CounterSeq ]
8303: [ 'CONST' ConstSeq ]
8304: [ 'VAR' VariableSeq ]
8305: 'RULES' ElemSeq
8306: [ 'ATTRIBUTES' AttrSeq ]
8307: [ 'PRESENTATION' PresSeq ]
1.30 cvs 8308: < 'TEXTTRANSLATE' TextTransSeq >
1.1 cvs 8309: [ 'SYMBTRANSLATE' TransSeq ]
8310: [ 'GRAPHTRANSLATE' TransSeq ]
8311: 'END' .
8312:
8313: LineLength = NUMBER .
8314:
1.30 cvs 8315: BufferSeq = Buffer < Buffer > .
1.1 cvs 8316: Buffer = BufferID [ '(' 'Picture' ')' ] ';' .
8317: BufferID = NAME .
8318:
1.30 cvs 8319: CounterSeq = Counter < Counter > .
1.1 cvs 8320: Counter = CounterID [ ':' CounterFunc ] ';' .
8321: CounterID = NAME .
8322: CounterFunc = 'Rank' 'of' ElemID [ SLevelAsc ]
8323: [ 'Init' AttrID ] /
8324: 'Rlevel' 'of' ElemID /
8325: 'Set' InitValue 'On' ElemID
8326: 'Add' Increment 'On' ElemID
8327: [ 'Init' AttrID ] .
8328: SLevelAsc = [ '-' ] LevelAsc .
8329: LevelAsc = NUMBER .
8330: InitValue = NUMBER .
8331: Increment = NUMBER .
8332: ElemID = NAME .
8333: AttrID = NAME .
8334:
1.30 cvs 8335: ConstSeq = Const < Const > .
1.1 cvs 8336: Const = ConstID '=' ConstValue ';' .
8337: ConstID = NAME .
8338: ConstValue = STRING .
8339:
1.30 cvs 8340: VariableSeq = Variable < Variable > .
8341: Variable = VarID ':' Function < Function > ';' .
1.1 cvs 8342: VarID = NAME .
8343: Function = 'Value' '(' CounterID [ ':' Length ]
8344: [ ',' CounterStyle ] ')' /
8345: 'FileDir' / 'FileName' / 'Extension' /
8346: 'DocumentName' / 'DocumentDir' /
8347: ConstID / CharString /
8348: BufferID / AttrID .
8349: Length = NUMBER .
8350: CounterStyle= 'Arabic' / 'LRoman' / 'URoman' /
8351: 'Uppercase' / 'Lowercase' .
8352: CharString = STRING .
8353:
1.30 cvs 8354: ElemSeq = TransType < TransType > .
1.1 cvs 8355: TransType = [ FirstSec ] ElemID ':' RuleSeq .
8356: FirstSec = 'First' / 'Second' .
1.30 cvs 8357: RuleSeq = Rule / 'BEGIN' < Rule > 'END' ';' .
1.1 cvs 8358: Rule = SimpleRule / ConditionBlock .
8359: ConditionBlock= 'IF' ConditionSeq SimpleRuleSeq .
1.30 cvs 8360: SimpleRuleSeq = 'BEGIN' < SimpleRule > 'END' ';' /
1.1 cvs 8361: SimpleRule .
8362:
8363: ConditionSeq = Condition [ 'AND' Condition ] .
8364: Condition = [ 'NOT' ] [ 'Target' ] Cond .
8365: Cond = CondElem / CondAscend .
8366: CondElem = 'FirstRef' / 'LastRef' /
8367: 'ExternalRef' /
8368: 'Alphabet' '=' Alphabet /
8369: 'ComputedPage' / 'StartPage' /
8370: 'UserPage' / 'ReminderPage' /
8371: 'Empty' /
1.18 cvs 8372: ElemID /
1.1 cvs 8373: 'FirstAttr' / 'LastAttr' .
8374: CondAscend = [ Ascend ] CondOnAscend .
8375: Ascend = '*' / 'Parent' / 'Ancestor' LevelOrType .
8376: LevelOrType = CondRelLevel / ElemID [ ExtStruct ] .
8377: CondRelLevel = NUMBER .
8378: CondOnAscend = 'First' / 'Last' /
8379: 'Referred' /
8380: [ 'Immediately' ] 'Within' [ NumParent ]
8381: ElemID [ ExtStruct ] /
8382: 'Attributes' /
8383: AttrID [ RelatAttr ] /
8384: 'Presentation' /
1.34 ! cvs 8385: PresRule .
1.1 cvs 8386: NumParent = [ GreaterLess ] NParent .
1.30 cvs 8387: GreaterLess = '>' / '<' .
1.1 cvs 8388: NParent = NUMBER.
8389: Alphabet = NAME .
8390: RelatAttr = '=' Value /
1.30 cvs 8391: '>' [ '-' ] Minimum /
1.1 cvs 8392: '<' [ '-' ] Maximum /
8393: 'IN' '[' [ '-' ] MinInterval '..'
8394: [ '-' ] MaxInterval ']' .
8395: Value = [ '-' ] IntegerVal / TextVal / AttrValue .
8396: Minimum = NUMBER .
8397: Maximum = NUMBER .
8398: MinInterval = NUMBER .
8399: MaxInterval = NUMBER .
8400: IntegerVal = NUMBER .
8401: TextVal = STRING .
8402: AttrValue = NAME .
8403:
8404: SimpleRule = 'Create' [ 'IN' VarID ] Object
8405: [ Position ] ';' /
8406: 'Write' Object [ Position ] ';' /
8407: 'Read' BufferID [ Position ] ';' /
8408: 'Include' File [ Position ] ';' /
1.6 cvs 8409: 'Get' [ RelPosition ] ElemID
8410: [ ExtStruct ]
8411: [ Position ] ';' /
1.1 cvs 8412: 'Copy' [ RelPosition ] ElemID
8413: [ ExtStruct ]
8414: [ Position ] ';' /
8415: 'Use' TrSchema [ 'For' ElemID ] ';' /
8416: 'Remove' ';' /
1.31 cvs 8417: 'Ignore' ';' /
1.1 cvs 8418: 'NoTranslation' ';' /
8419: 'NoLineBreak' ';' /
8420: 'ChangeMainFile' VarID [ Position ] ';' /
1.14 cvs 8421: 'RemoveFile' VarID [ Position ] ';' /
1.10 cvs 8422: 'Set' CounterID InitValue [ Position ] ';' /
8423: 'Add' CounterID Increment [ Position ] ';' /
1.25 cvs 8424: 'Indent' [ 'IN' VarID ] Indent [ Position ] ';' .
1.10 cvs 8425:
1.25 cvs 8426: Indent = 'Suspend' / 'Resume' / [ IndentSign ] IndentValue .
1.10 cvs 8427: IndentSign = '+' / '-' .
8428: IndentValue = NUMBER .
1.1 cvs 8429:
8430: Object = ConstID / CharString /
8431: BufferID /
8432: VarID /
1.30 cvs 8433: '(' Function < Function > ')' /
1.21 cvs 8434: [ 'Translated' ] AttrID /
1.1 cvs 8435: 'Value' /
8436: 'Content' /
8437: 'Attributes' /
8438: 'Presentation' /
8439: 'RefId' /
8440: 'PairId' /
8441: 'FileDir' / 'FileName' / 'Extension' /
8442: 'DocumentName' / 'DocumentDir' /
8443: [ 'Referred' ] ReferredObject .
8444: Position = 'After' / 'Before' .
8445:
1.6 cvs 8446: ReferredObject= VarID /
8447: ElemID [ ExtStruct ] /
8448: 'RefId' /
8449: 'DocumentName' / 'DocumentDir' .
1.1 cvs 8450:
1.6 cvs 8451: File = FileName / BufferID .
8452: FileName = STRING .
1.1 cvs 8453:
1.6 cvs 8454: RelPosition = 'Included' / 'Referred' .
8455: ExtStruct = '(' ElemID ')' .
1.1 cvs 8456:
1.6 cvs 8457: TrSchema = NAME .
8458:
1.30 cvs 8459: AttrSeq = TransAttr < TransAttr > .
1.6 cvs 8460: TransAttr = AttrID [ '(' ElemID ')' ]
8461: [ RelatAttr ] ':' RuleSeq .
8462:
1.30 cvs 8463: PresSeq = PresTrans < PresTrans > .
1.6 cvs 8464: PresTrans = PresRule ':' RuleSeq .
8465: PresRule = 'Size' [ PresRelation ] /
8466: 'Indent' [ PresRelation ] /
8467: 'LineSpacing' [ PresRelation ] /
8468: 'Adjust' [ '=' AdjustVal ] /
8469: 'Justify' [ '=' BoolVal ] /
8470: 'Hyphenate' [ '=' BoolVal ] /
8471: 'Style' [ '=' StyleVal ] /
1.24 cvs 8472: 'Weight' [ '=' WeightVal ] /
1.6 cvs 8473: 'Font' [ '=' FontVal ] /
8474: 'UnderLine' [ '=' UnderLineVal ] /
8475: 'Thickness' [ '=' ThicknessVal ] /
8476: 'LineStyle' [ '=' LineStyleVal ] /
8477: 'LineWeight' [ PresRelation ] /
8478: 'FillPattern' [ '=' Pattern ] /
8479: 'Background' [ '=' Color ] /
8480: 'Foreground' [ '=' Color ] .
8481:
8482: PresRelation = '=' PresValue /
1.30 cvs 8483: '>' [ '-' ] PresMinimum /
1.6 cvs 8484: '<' [ '-' ] PresMaximum /
8485: 'IN' '[' [ '-' ] PresIntervalMin '..'
8486: [ '-' ] PresIntervalMax ']' .
8487: AdjustVal = 'Left' / 'Right' / 'VMiddle' /
8488: 'LeftWithDots' .
8489: BoolVal = 'Yes' / 'No' .
1.24 cvs 8490: StyleVal = 'Roman' / 'Italics' / 'Oblique' .
8491: WeightVal = 'Normal' / 'Bold' .
1.6 cvs 8492: FontVal = 'Times' / 'Helvetica' / 'Courier' .
8493: UnderLineVal = 'NoUnderline' / 'UnderLined' /
8494: 'OverLined' / 'CrossedOut' .
8495: ThicknessVal = 'Thick' / 'Thin' .
8496: LineStyleVal = 'Solid' / 'Dashed' / 'Dotted' .
8497: Pattern = NAME .
8498: Color = NAME .
8499: PresMinimum = NUMBER .
8500: PresMaximum = NUMBER .
1.1 cvs 8501: PresIntervalMin= NUMBER .
8502: PresIntervalMax= NUMBER .
1.6 cvs 8503: PresValue = [ '-' ] PresVal .
8504: PresVal = NUMBER .
1.1 cvs 8505:
1.6 cvs 8506: TextTransSeq = [ Alphabet ] TransSeq .
8507: Alphabet = NAME .
1.30 cvs 8508: TransSeq = 'BEGIN' < Translation > 'END' ';' /
1.6 cvs 8509: Translation .
1.30 cvs 8510: Translation = Source [ '->' Target ] ';' .
1.6 cvs 8511: Source = STRING .
1.18 cvs 8512: Target = STRING .</pre>
8513: </div>
8514: <hr>
8515: </div>
1.1 cvs 8516:
1.18 cvs 8517: <div class="chapter">
8518: <h1><a name="sect7">Character coding</a></h1>
1.1 cvs 8519:
1.18 cvs 8520: <div class="section">
1.30 cvs 8521: <h2><a name="sectb71">Characters</a></h2>
1.1 cvs 8522:
1.30 cvs 8523: <p>The characters of the Latin alphabet follow the encoding defined in the ISO
1.5 cvs 8524: 8859-1 (ISO Latin-1) standard. The characters of the Greek alphabet follow
1.18 cvs 8525: the encoding defined by Adobe for its Symbol font (Adobe FontSpecific).</p>
1.30 cvs 8526:
8527: <p>Characters whose octal code is greater than 0200 are written in the form of
1.1 cvs 8528: their octal code preceded by a backslash character (``\''). For example, the
1.30 cvs 8529: French word 'Résumé' is written <tt>R\351sum\351</tt>.</p>
8530:
8531: <p>To the ISO 8859-1 encoding four characters with the following codes have
8532: been added:<br>
1.18 cvs 8533: <tt>212</tt>: line break<br>
8534: <tt>240</tt>: sticky space<br>
8535: <tt>201</tt>: thin space<br>
8536: <tt>202</tt>: en space</p>
1.30 cvs 8537:
8538: <p>The <tt>212</tt> character is a ``line break'' character which forces a
8539: line break. The <tt>240</tt> character is a ``sticky space'', which cannot be
1.18 cvs 8540: replaced by a line break.</p>
8541: </div>
1.1 cvs 8542:
1.18 cvs 8543: <div class="section">
1.30 cvs 8544: <h2><a name="sectb72">Symbols</a></h2>
1.1 cvs 8545:
1.30 cvs 8546: <p>The table below gives the codes for the symbols of Thot. Symbols can be
8547: used in presentation schemas constants and in transcoding rules of translation
1.18 cvs 8548: schemas. Each symbol is represented by a single character.</p>
8549: <ul>
1.30 cvs 8550: <li><tt>r</tt>: a radical</li>
8551: <li><tt>i</tt>: a simple integral</li>
8552: <li><tt>c</tt>: a curvilinear integral</li>
8553: <li><tt>d</tt>: a double integral</li>
8554: <li><tt>t</tt>: a triple integral</li>
8555: <li><tt>S</tt>: the summation symbol</li>
8556: <li><tt>P</tt>: the product symbol</li>
8557: <li><tt>U</tt>: the union symbol</li>
8558: <li><tt>I</tt>: the intersection symbol</li>
8559: <li><tt>></tt>: a right arrow</li>
8560: <li><tt><</tt>: a left arrow</li>
8561: <li><tt>^</tt>: an up arrow</li>
8562: <li><tt>V</tt>: a down arrow</li>
8563: <li><tt>(</tt>: an opening parenthesis</li>
8564: <li><tt>)</tt>: a closing parenthesis</li>
8565: <li><tt>{</tt>: an opening brace</li>
8566: <li><tt>}</tt>: a closing brace</li>
8567: <li><tt>[</tt>: an opening bracket</li>
8568: <li><tt>]</tt>: a closing bracket</li>
1.18 cvs 8569: </ul>
8570: </div>
1.1 cvs 8571:
1.18 cvs 8572: <div class="section">
1.30 cvs 8573: <h2><a name="sectb73">Graphical elements</a></h2>
1.1 cvs 8574:
1.30 cvs 8575: <p>The table below gives the codes for the graphical elements of Thot. These
1.1 cvs 8576: elements can be used in presentation schemas constants and in transcoding
8577: rules of translation schemas. Each graphical element is represented by a
1.18 cvs 8578: single character.</p>
8579: <ul>
1.30 cvs 8580: <li>a: a circle</li>
8581: <li><p><tt>A</tt>: an open curve with an arrow head at the end</p>
8582: </li>
8583: <li><tt>b</tt>: a horizontal line along the lower side of the box</li>
8584: <li><tt>B</tt>: an open curve</li>
8585: <li><tt>c</tt>: an ellipse inscribed in the box</li>
8586: <li><tt>C</tt>: a rectangle with rounded corners</li>
8587: <li><tt>D</tt>: an open curve with two arrow heads</li>
8588: <li><tt>e</tt>: The northwest/southeast diagonal of the box with an
8589: arrowhead at the bottom</li>
8590: <li><tt>E</tt>: The southwest/northeast diagonal of the box with an
8591: arrowhead at the top</li>
8592: <li><tt>F</tt>: an open curve with an arrow head at start</li>
8593: <li><tt>g</tt>: a line from the origin of the box to its opposite
8594: corner</li>
8595: <li><tt>h</tt>: a horizontal line as wide as the box and placed in its
8596: middle</li>
8597: <li><tt>l</tt>: a vertical line on the left side of the box</li>
8598: <li><tt>L</tt>: a lozenge</li>
8599: <li><tt>M</tt>: an open broken line with two arrow heads</li>
8600: <li><tt>N</tt>: an open broken line with an arrow head at start</li>
8601: <li><tt>o</tt>: The southwest/northeast diagonal of the box with an
8602: arrowhead at the bottom</li>
8603: <li><tt>O</tt>: The northwest/southeast diagonal of the box with an
8604: arrowhead at the top</li>
8605: <li><tt>p</tt>: a polygon</li>
8606: <li><tt>P</tt>: a rectangle with round corners and a horizontal bar at the
8607: top</li>
8608: <li><tt>Q</tt>: an ellipse with a horizontal bar at the top</li>
8609: <li><tt>r</tt>: a vertical line on the right side of the box</li>
8610: <li><tt>R</tt>: a rectangle which is the shape of the box</li>
8611: <li><tt>s</tt>: a closed curve</li>
8612: <li><tt>S</tt>: an open broken line</li>
8613: <li><tt>t</tt>: a horizontal line along the upper side of the box</li>
8614: <li><tt>U</tt>: an open broken line with an arrow head at the end</li>
8615: <li><tt>v</tt>: a vertical line as tall as the box and placed in its
8616: middle</li>
8617: <li><tt>V</tt>: a down arrow as tall as the box and in its middle</li>
8618: <li>w: a segment (2 points)</li>
8619: <li><tt>W</tt>: the upper right corner</li>
8620: <li>x: a segment (2 points) with an arrow head at the end</li>
8621: <li><tt>X</tt>: the lower right corner</li>
8622: <li>y: a segment (2 points) with an arrow head at the end</li>
8623: <li><tt>Y</tt>: the lower left corner</li>
8624: <li>z: a segment (2 points) with an arrow head at the end</li>
8625: <li><tt>Z</tt>: the upper left corner</li>
8626: <li><tt>space</tt>: a transparent element</li>
8627: <li><tt>^</tt>: an up arrow as tall as the box and in its middle</li>
8628: <li><tt>></tt>: a right arrow as long as the box's width and in its
8629: middle</li>
8630: <li><tt>></tt>: a left arrow as long as the box's width and in its
8631: middle</li>
8632: <li><tt>/</tt>: The southwest/northeast diagonal of the box</li>
8633: <li><tt>\</tt>: the northwest/southeast diagonal of the box</li>
1.18 cvs 8634: </ul>
8635: <hr>
8636: </div>
8637: </div>
8638: </body>
8639: </html>
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