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3: <HEAD>
4: <TITLE>The Languages of Thot</TITLE>
5: </HEAD>
6: <BODY>
7:
8: <DIV class="frontmatter" align=center>
9: <H1>The Languages of Thot</H1>
10:
11: <H3>Vincent Quint</H3>
12:
1.6 cvs 13: <H4>Translated from French by Ethan Munson</H4>
1.1 cvs 14:
1.12 ! cvs 15: <H4>Version of March 26, 1997</H4>
1.1 cvs 16:
1.6 cvs 17: <P>© 1996 INRIA
18:
19: <HR>
20: </DIV>
21:
22: <DIV class="tableofcontents">
23: <H2><A href="languages.toc.html">Contents</A></H2>
24: <UL>
25: <LI><BIG><A href="#sect2">The document model of Thot</A></BIG>
26: <UL>
27: <LI><STRONG><A href="#sectb21">The logical structure of documents</A></STRONG>
28: <LI><STRONG><A href="#sectb22">Generic and specific structures</A></STRONG>
29: <LI><STRONG><A href="#sectb23">Logical structure and physical structure</A></STRONG>
30: <LI><STRONG><A href="#sectb24">Document structures and object structures</A></STRONG>
31: </UL>
32:
33: <LI><BIG><A href="#sect3">The S language</A></BIG>
34: <UL>
35: <LI><STRONG><A href="#sectb31">Document meta-structure</A></STRONG>
36: <UL>
37: <LI><A href="#sectc311">The basic types</A>
38: <LI><A href="#sectc312">Constructed elements</A>
39: <LI><A href="#sectc313">Logical structure constructors</A>
40: <UL>
41: <LI><SMALL><A href="#sectd3131">Aggregate and List</A></SMALL>
42: <LI><SMALL><A href="#sectd3132">Choice, Schema, and Unit</A></SMALL>
43: <LI><SMALL><A href="#sectd3133">Reference and Inclusion</A></SMALL>
44: <LI><SMALL><A href="#sectd3134">Mark pairs</A></SMALL>
45: <LI><SMALL><A href="#sectd3135">Restrictions and Extensions</A></SMALL>
46: <LI><SMALL><A href="#sectd3136">Summary</A></SMALL>
47: </UL>
48: <LI><A href="#sectc314">Associated Elements</A>
49: <LI><A href="#sectc315">Attributes</A>
50: <LI><A href="#sectc316">Discussion of the model</A>
51: </UL>
52: <LI><STRONG><A href="#sectb32">The definition language for generic structures</A></STRONG>
53: <UL>
54: <LI><A href="#sectc321">Writing Conventions</A>
55: <LI><A href="#sectc322">Extension schemas</A>
56: <LI><A href="#sectc323">The general organization of structure schemas</A>
57: <LI><A href="#sectc324">The default presentation</A>
58: <LI><A href="#sectc325">Global Attributes</A>
59: <LI><A href="#sectc326">Parameters</A>
60: <LI><A href="#sectc327">Structured elements</A>
61: <LI><A href="#sectc328">Structure definitions</A>
62: <UL>
63: <LI><SMALL><A href="#sectd3281">List</A></SMALL>
64: <LI><SMALL><A href="#sectd3282">Aggregate</A></SMALL>
65: <LI><SMALL><A href="#sectd3283">Choice</A></SMALL>
66: <LI><SMALL><A href="#sectd3284">Reference</A></SMALL>
67: <LI><SMALL><A href="#sectd3285">Mark pairs</A></SMALL>
68: </UL>
69: <LI><A href="#sectc329">Imports</A>
70: <LI><A href="#sectc3210">Extension rules</A>
71: <LI><A href="#sectc3211">Associated elements</A>
72: <LI><A href="#sectc3212">Units</A>
73: <LI><A href="#sectc3213">Skeleton elements</A>
74: <LI><A href="#sectc3214">Exceptions</A>
75: </UL>
76: <LI><STRONG><A href="#sectb33">Some examples</A></STRONG>
77: <UL>
78: <LI><A href="#sectc331">A class of documents: articles</A>
79: <LI><A href="#sectc332">A class of objects: mathematical formulas</A>
1.8 cvs 80: </UL>
1.6 cvs 81: </UL>
82:
1.8 cvs 83: <LI><BIG><A href="#sect4">The P language</A></BIG>
1.6 cvs 84: <UL>
85: <LI><STRONG><A href="#sectb41">Document presentation</A></STRONG>
86: <UL>
87: <LI><A href="#sectc411">Two levels of presentation</A>
88: <LI><A href="#sectc412">Boxes</A>
89: <LI><A href="#sectc413">Views and visibility</A>
90: <LI><A href="#sectc414">Pages</A>
91: <LI><A href="#sectc415">Numbering</A>
92: <LI><A href="#sectc416">Presentation parameters</A>
93: </UL>
94: <LI><STRONG><A href="#sectb42">Presentation description language</A></STRONG>
95: <UL>
96: <LI><A href="#sectc421">The organization of a presentation schema</A>
97: <LI><A href="#sectc422">Views</A>
98: <LI><A href="#sectc423">Print Views</A>
99: <LI><A href="#sectc424">Counters</A>
100: <LI><A href="#sectc425">Presentation constants</A>
101: <LI><A href="#sectc426">Variables</A>
102: <LI><A href="#sectc427">Default presentation rules</A>
103: <LI><A href="#sectc428">Presentation and page layout boxes</A>
104: <LI><A href="#sectc429">Presentation of structured elements</A>
105: <LI><A href="#sectc4210">Logical attribute presentation</A>
106: <LI><A href="#sectc4212">Value transmission rules</A>
107: <LI><A href="#sectc4213">Presentation rules</A>
108: <LI><A href="#sectc4214">Conditions applying to presentation rules</A>
109: <UL>
110: <LI><SMALL><A href="#sectd42141">Conditions based on the logical position of the element</A></SMALL>
111: <LI><SMALL><A href="#sectd42142">Conditions on references</A></SMALL>
112: <LI><SMALL><A href="#sectd42143">Conditions on logical attributes</A></SMALL>
113: <LI><SMALL><A href="#sectd42144">Conditions on page breaks</A></SMALL>
114: <LI><SMALL><A href="#sectd42145">Conditions on the element's content</A></SMALL>
115: <LI><SMALL><A href="#sectd42146">Conditions on counters</A></SMALL>
116: </UL>
117: <LI><A href="#sectc4215">A presentation rule</A>
118: <LI><A href="#sectc4216">Box axes</A>
119: <LI><A href="#sectc4217">Distance units</A>
120: <LI><A href="#sectc4218">Relative positions</A>
121: <LI><A href="#sectc4219">Box extents</A>
122: <UL>
123: <LI><SMALL><A href="#sectd42191">Fixed extents</A></SMALL>
124: <LI><SMALL><A href="#sectd42192">Relative extents</A></SMALL>
125: <LI><SMALL><A href="#sectd42193">Elastic extents</A></SMALL>
126: </UL>
127: <LI><A href="#sectc4220">Overflow</A>
128: <LI><A href="#sectc4221">Inheritance</A>
129: <LI><A href="#sectc4222">Line breaking</A>
130: <UL>
131: <LI><SMALL><A href="#sectd42221">Line spacing</A></SMALL>
132: <LI><SMALL><A href="#sectd42222">First line indentation</A></SMALL>
133: <LI><SMALL><A href="#sectd42223">Alignment</A></SMALL>
134: <LI><SMALL><A href="#sectd42224">Justification</A></SMALL>
135: <LI><SMALL><A href="#sectd42225">Hyphenation</A></SMALL>
136: <LI><SMALL><A href="#sectd42226">Avoiding line breaking</A></SMALL>
137: </UL>
138: <LI><A href="#sectc4223">Page breaking and line breaking conditions</A>
139: <LI><A href="#sectc4224">Visibility</A>
140: <LI><A href="#sectc4225">Character style parameters</A>
141: <UL>
142: <LI><SMALL><A href="#sectd42251">Character size</A></SMALL>
143: <LI><SMALL><A href="#sectd42252">Font and character style</A></SMALL>
144: <LI><SMALL><A href="#sectd42253">Underlining</A></SMALL>
145: </UL>
146: <LI><A href="#sectc4226">Stacking order</A>
147: <LI><A href="#sectc4227">Line Style</A>
148: <LI><A href="#sectc4228">Line thickness</A>
149: <LI><A href="#sectc4229">Fill pattern</A>
150: <LI><A href="#sectc4230">Colors</A>
151: <LI><A href="#sectc4231">Presentation box content</A>
152: <LI><A href="#sectc4232">Presentation box creation</A>
153: <LI><A href="#sectc4233">Page layout</A>
154: <LI><A href="#sectc4234">Box copies</A>
155: </UL>
156: </UL>
157:
158: <LI><BIG><A href="#sect5">The T language</A></BIG>
159: <UL>
160: <LI><STRONG><A href="#sectb51">Document translation</A></STRONG>
161: <UL>
162: <LI><A href="#sectc511">Translation principles</A>
163: <LI><A href="#sectc512">Translation procedure</A>
164: </UL>
165: <LI><STRONG><A href="#sectb52">Translation definition language</A></STRONG>
166: <UL>
167: <LI><A href="#sectc521">Organization of a translation schema</A>
168: <LI><A href="#sectc522">Line length</A>
169: <LI><A href="#sectc523">Buffers</A>
170: <LI><A href="#sectc524">Counters</A>
171: <LI><A href="#sectc525">Constants</A>
172: <LI><A href="#sectc526">Variables</A>
173: <LI><A href="#sectc527">Translating structure elements</A>
174: <LI><A href="#sectc528">Conditional rules</A>
175: <UL>
176: <LI><SMALL><A href="#sectd5281">Conditions based on the logical position of the element</A></SMALL>
177: <LI><SMALL><A href="#sectd5282">Conditions on references</A></SMALL>
178: <LI><SMALL><A href="#sectd5283">Conditions on the parameters</A></SMALL>
179: <LI><SMALL><A href="#sectd5284">Conditions on the alphabets</A></SMALL>
180: <LI><SMALL><A href="#sectd5285">Conditions on page breaks</A></SMALL>
181: <LI><SMALL><A href="#sectd5286">Conditions on the element's content</A></SMALL>
182: <LI><SMALL><A href="#sectd5287">Conditions on the presence of comments</A></SMALL>
183: <LI><SMALL><A href="#sectd5288">Conditions on the presence of specific presentation rules</A></SMALL>
184: <LI><SMALL><A href="#sectd5289">Conditions on the presence of logical attributes</A></SMALL>
185: <LI><SMALL><A href="#sectd52810">Conditions on logical attributes</A></SMALL>
186: <LI><SMALL><A href="#sectd52811">Conditions on specific presentation rules</A></SMALL>
187: </UL>
188: <LI><A href="#sectc529">Translation rules</A>
189: <LI><A href="#sectc5210">The <TT>Create</TT> rule</A>
190: <LI><A href="#sectc5211">The <TT>Write</TT> rule</A>
191: <LI><A href="#sectc5212">The <TT>Read</TT> rule</A>
192: <LI><A href="#sectc5213">The <TT>Include</TT> rule</A>
193: <LI><A href="#sectc5214">The <TT>Get</TT> rule</A>
194: <LI><A href="#sectc5215">The <TT>Copy</TT> rule</A>
195: <LI><A href="#sectc5216">The <TT>Use</TT> rule</A>
196: <LI><A href="#sectc5217">The <TT>Remove</TT> rule</A>
197: <LI><A href="#sectc5218">The <TT>NoTranslation</TT> rule</A>
198: <LI><A href="#sectc5219">The <TT>NoLineBreak</TT> rule</A>
199: <LI><A href="#sectc5220">The <TT>ChangeMainFile</TT> rule</A>
200: <LI><A href="#sectc5221">The <TT>Set</TT> and <TT>Add</TT> rules</A>
1.10 cvs 201: <LI><A href="#sectc5221a">The <TT>Indent</TT> rule</A>
1.6 cvs 202: <LI><A href="#sectc5222">Rule application order</A>
203: <LI><A href="#sectc5223">Translation of logical attributes</A>
204: <LI><A href="#sectc5224">Translation of specific presentations</A>
205: <LI><A href="#sectc5225">Recoding of characters, symbols and graphics</A>
206: </UL>
207: </UL>
208:
209: <LI><BIG><A href="#sect6">Language grammars</A></BIG>
210: <UL>
211: <LI><STRONG><A href="#sectb61">The M meta-language</A></STRONG>
212: <LI><STRONG><A href="#sectb62">The S language</A></STRONG>
213: <LI><STRONG><A href="#sectb63">The P language</A></STRONG>
214: <LI><STRONG><A href="#sectb64">The T language</A></STRONG>
215: </UL>
216:
217: <LI><BIG><A href="#sect7">Character coding</A></BIG>
218: <UL>
219: <LI><STRONG><A href="#sectb71">Characters</A></STRONG>
220: <LI><STRONG><A href="#sectb72">Symbols</A></STRONG>
221: <LI><STRONG><A href="#sectb73">Graphical elements</A></STRONG>
222: </UL>
223: </UL>
1.1 cvs 224: <HR>
225: </DIV>
226:
227: <DIV class="chapter">
1.6 cvs 228: <H1><A name=sect2>The document model of Thot</A></H1>
1.1 cvs 229:
230: <P>
231: All of the services which Thot provides to the user are based on the system's
232: internal document representation. This representation is itself derived from
233: the document model which underlies Thot. The model is presented here, prior
234: to the description of the languages which permit the generic specification of
235: documents.</P>
236:
237: <DIV class="section">
1.6 cvs 238: <H2><A name=sectb21>The logical structure of documents</A></H2>
1.1 cvs 239:
240: <P>
241: The document model of Thot is primarily designed to allow the user to operate
1.5 cvs 242: on those entities which s/he has in mind when s/he works on a document. The
243: model makes no assumptions about the nature of these entities. It is
244: essentially these logical entities, such as paragraphs, sections, chapters,
245: notes, titles, and cross-references which give a document its logical
246: structure.</P>
1.1 cvs 247: <P>
1.5 cvs 248: Because of this model, the author can divide the document into chapters,
1.1 cvs 249: giving each one a title. The content of these chapters can be further divided
1.2 cvs 250: into sections, subsections, etc. The text is organized into successive
251: paragraphs, according to the content. In the writing phase, the lines, pages,
252: margins, spacing, fonts, and character styles are not very important. In fact,
253: if the system requires documents to be written in these terms, it gets in the
254: way. So, Thot's model is primarily based on the logical aspect of documents.
255: The creation of a model of this type essentially requires the definition :</P>
1.1 cvs 256: <UL>
257: <LI>of the entities which can appear in the documents,
258: <LI>and the relations between these entities.
259: </UL>
260: <P>
261: The choice of entities to include in the model can be subtle. Some documents
262: require chapters, while others only need various levels of sections. Certain
263: documents contain appendices, others don't. In different documents the same
264: logical entity may go by different names (e.g. ``Conclusion'' and
265: ``Summary''). Certain entities which are absolutely necessary in some
266: documents, such as clauses in a contract or the address of the recipient in a
267: letter, are useless in most other cases.</P>
268: <P>
269: The differences between documents result from more than just the entities that
270: appear in them, but also from the relationships between these entities and the
271: ways that they are linked. In certain documents, notes are spread throughout
272: the document, for example at the bottom of the page containing the
273: cross-reference to them, while in other documents they are collected at the
274: end of each chapter or even at the end of the work. As another example, the
275: introduction of some documents can contain many sections, while in other
276: documents, the introduction is restricted to be a short sequence of
277: paragraphs.</P>
278: <P>
279: All of this makes it unlikely that a single model can describe any document at
280: a relatively high level. It is obviously tempting to make up a list of widely
281: used entities, such as chapters, sections, paragraphs, and titles, and then
282: map all other entities onto the available choices. In this way, an
283: introduction can be supported as a chapter and a contract clause supported as
284: a paragraph or section. However, in trying to widen the range of usage of
285: certain entities, their meaning can be lost and the power of the model
286: reduced. In addition, while this widening partially solves the problem of
287: choosing entities, it does not solve the problem of their organization: when a
288: chapter must be composed of sections, how does one indicate that an
289: introduction has none when it is merely another chapter? One solution is to
290: include introductions in the list of supported entities. But then, how does
291: one distinguish those introductions which are allowed to have sections from
292: those which are not. Perhaps this could be done by defining two types of
293: introduction. Clearly, this approach risks an infinite expansion of the list
294: of widely used entities.</P>
295: </DIV>
296:
297: <DIV class="section">
1.6 cvs 298: <H2><A name=sectb22>Generic and specific structures</A></H2>
1.1 cvs 299:
300: <P>
301: Thus, it is apparently impossible to construct an exhaustive inventory of all
1.2 cvs 302: those entities which are necessary and sufficient to precisely describe any
303: document. It also seems impossible to specify all possible arrangements of
304: these entities in a document. This is why Thot uses a <EM>meta-model</EM>
305: instead, which permits the description of numerous <EM>models</EM>, each one
306: describing a <EM>class</EM> of documents.</P>
1.1 cvs 307: <P>
308: A <EM>class</EM> is a set of documents having very similar structure. Thus,
309: the collection of research reports published by a laboratory constitutes a
310: class; the set of commercial proposals by the sales department of a company
311: constitutes another class; the set of articles published by a journal
312: constitutes a third class. Clearly, it is not possible to enumerate every
313: possible document class. It is also clear that new document classes must be
314: created to satisfy new needs and applications.</P>
315: <P>
316: To give a more rigorous definition of classes, we must introduce the ideas of
317: <EM>generic structure</EM> and <EM>specific structure</EM>. Each document has
318: a <EM>specific structure</EM> which organizes the various parts which comprise
319: it. We illustrate this with the help of a simple example comparing two
320: reports, A and B (<A href="#specstruct">see Figure</A>). The report A contains
321: an introduction followed by three chapters and a conclusion. The first
322: chapter contains two sections, the second, three sections. That is the
323: <EM>specific</EM> structure of document A. Similarly, the structure of
324: document B is: an introduction, two chapters, a conclusion; Chapter 1 has
325: three sections while Chapter 2 has four. The specific structures of these two
326: documents are thus different.</P>
327:
328: <DIV class="figure">
329: <HR>
330: <PRE>
331: Report A Report B
332: Introduction Introduction
333: Chapter 1 Chapter 1
334: Section 1.1 Section 1.1
335: Section 1.2 Section 1.2
336: Chapter 2 Section 1.3
337: Section 2.1 Chapter 2
338: Section 2.2 Section 2.1
339: Section 2.3 Section 2.2
340: Chapter 3 Section 2.3
341: Conclusion Section 2.4
342: Conclusion
343: </PRE>
344: <P align=center>
345: <EM><A name="specstruct">Two specific structures</A></EM></P>
346: <HR>
347: </DIV>
348: <P>
349: The <EM>generic structure</EM> defines the ways in which specific structures
350: can be constructed. It specifies how to generate specific structures. The
351: reports A and B, though different, are constructed in accordance with the same
352: generic structure, which specifies that a report contains an introduction
353: followed by a variable number of chapters and a conclusion, with each chapter
354: containing a variable number of sections.</P>
355: <P>
356: There is a one-to-one correspondence between a class and a generic structure:
357: all the documents of a class are constructed in accordance with the same
358: generic structure. Hence the definition of the class: a class is a set of
359: documents whose specific structure is constructed in accordance with the same
360: generic structure. A class is characterized by its generic structure.</P>
361: <P>
362: Thus, a generic structure can be considered to be a model at the level which
363: interests us, but only for one class of documents. When the definition is
364: limited to a single class of documents, it is possible to define a model which
365: does a good job of representing the documents of the class, including the
366: necessary entities and unencumbered by useless entities. The description of
367: the organization of the documents in the class can then be sufficiently
368: precise.</P>
369: </DIV>
370:
371: <DIV class="section">
1.6 cvs 372: <H2><A name=sectb23>Logical structure and physical structure</A></H2>
1.1 cvs 373:
374: <P>
375: Generic structures only describe the <EM>logical</EM> organization of
376: documents, not their <EM>physical</EM> presentation on a screen or on sheets
377: of paper. However, for a document to be displayed or printed, its graphic
378: presentation must be taken into account.</P>
379: <P>
380: An examination of current printed documents shows that the details of
381: presentation essentially serve to bring out their logical structure. Outside
382: of some particular domains, notably advertising, the presentation is rarely
383: independent of the logical organization of the text. Moreover, the art of
384: typography consists of enhancing the organization of the text being set,
385: without catching the eye of the reader with overly pronounced effects. Thus,
386: italic and boldface type are used to emphasize words or expressions which have
387: greater significance than the rest of the text: keywords, new ideas,
388: citations, book titles, etc. Other effects highlight the organization of the
389: text: vertical space, margin changes, page breaks, centering, eventually
390: combined with the changes in the shapes or weight of the characters. These
391: effects serve to indicate the transitions between paragraphs, sections, or
392: chapters: an object's level in the logical structure of the document is shown
393: by the markedness of the effects.</P>
394: <P>
395: Since the model permits the description of all of the logical structure of the
396: document, the presentation can be derived from the model without being
397: submerged in the document itself. It suffices to use the logical structure of
398: the document to make the desired changes in its presentation: changes in type
399: size, type style, spacing, margin, centering, etc.</P>
400: <P>
401: Just as one cannot define a unique generic logical structure for all document
402: classes, one cannot define universal presentation rules which can be applied
403: to all document classes. For certain types of documents the chapter titles
404: will be centered on the page and printed in large, bold type. For other
405: documents, the same chapter titles will be printed in small, italic type and
406: aligned on the left margin.</P>
407: <P>
408: Therefore, it is necessary to base the presentation specifications for
409: documents on their class. Such a specification can be very fine-grained,
410: because the presentation is expressed in terms of the entities defined in the
411: generic logical structure of the class. Thus, it is possible to specify a
412: different presentation for the chapter titles and the section titles, and
413: similarly to specify titles for the sections according to their level in the
414: section hierarchy. The set of rules which specify the presentation of all the
415: elements defined in a generic logical structure is called a <EM>generic
416: presentation</EM>.</P>
417: <P>
418: There are several advantages derived from having a presentation linked to the
419: generic structure and described by a generic presentation. Homogeneity is the
420: first. Since every document in a class corresponds to the same generic
421: logical structure, a homogenous presentation for different documents of the
422: same class can be assured by applying the same generic presentation to all
423: documents of the class. Homogeneity of presentation can also be found among
1.2 cvs 424: the entities of a single document: every section heading will be presented in
1.1 cvs 425: the same way, the first line of every paragraph of the same type will have the
426: same indentation, etc.</P>
427: <P>
428: Another advantage of this approach to presentation is that it facilitates
429: changes to the graphical aspect of documents. A change to the generic
430: presentation rules attached to each type of entity will alter the presentation
431: of the entire document, and will do so homogenously. In this case, the
432: internal homogeneity of the class is no longer assured, but the way to control
433: it is simple. It suffices to adopt a single generic presentation for the
434: entire class.</P>
435: <P>
436: If the presentation of the class does not have to be homogenous, then the
437: appearance of the document can be adapted to the way it will be used or to the
438: device used to render it. This quality is sufficient to allow the existence
439: of <A name="mulpres">many generic presentations</A> for the same document
440: class. By applying one or the other of these presentations to it, the document
441: can be seen under different graphical aspects. It must be emphasized that
442: this type of modification of the presentation is not a change to the document
443: itself (in its specific logical structure or its content), but only in its
444: appearance at the time of editing or printing.</P>
445: </DIV>
446:
447: <DIV class="section">
1.6 cvs 448: <H2><A name=sectb24>Document structures and object structures</A></H2>
1.1 cvs 449:
450: <P>
451: So far, we have only discussed the global structure of documents and have not
452: considered the contents found in that structure. We could limit ourselves to
453: purely textual contents by assuming that a title or a paragraph contains a
454: simple linear text. But this model would be too restrictive. In fact,
455: certain documents contain not only text, but also contain tables, diagrams,
456: photographs, mathematical formulas, and program fragments. The model must
457: permit the representation of such <EM>objects</EM>.</P>
458: <P>
459: Just as with the whole of the document, the model takes into account the
460: logical structure of objects of this type. Some are clearly structured,
461: others are less so. Logical structure can be recognized in mathematical
462: formulas, in tables, and in certain types of diagrams. On the other hand, it
463: is difficult to define the structure of a photograph or of some drawings. But
464: in any case, it does not seem possible to define one unique structure which
465: can represent every one of these types of objects. The approach taken in the
466: definition of meta-structure and document classes also applies to objects.
467: Object classes can be defined which put together objects of similar type,
468: constructed from the same generic logical structure.</P>
469: <P>
470: Thus, a mathematical class can be defined and have a generic logical structure
471: associated with it. But even if a single generic structure can represent a
472: sufficient variety of mathematical formulas, for other objects with less
473: rigorous structure, multiple classes must be defined. As for documents, using
474: multiple classes assures that the model can describe the full range of objects
475: to be presented. It also permits the system to support objects which were not
476: initially anticipated. Moreover, this comment applies equally to mathematics:
477: different classes of formulas can be described depending on the domain of
478: mathematics being described.</P>
479: <P>
480: Since objects have the same level of logical representation as documents, they
481: gain the same advantages. In particular, it is possible to define the
482: presentation separately from the objects themselves and attach it to the
483: class. Thus, as for documents, objects of the same type have a uniform
484: presentation and the presentation of every object in a given class can be
485: changed simply by changing the generic presentation of the class. Another
486: advantage of using this document model is that the system does not bother the
487: user with the details of presentation, but rather allows the user to
488: concentrate on the logical aspect of the document and the objects.</P>
489: <P>
490: It is clear that the documents in a class do not necessarily use the same
491: classes of objects: one technical report will contain tables while another
492: report will have no tables but will use mathematical formulas. The usable
1.2 cvs 493: object classes are not always mentioned in a limiting way in the generic
494: logical structure of documents. Rather, they can be chosen freely from a
495: large set, independent of the document class.</P>
1.1 cvs 496: <P>
497: Thus, the object classes will be made commonplace and usable in every
498: document. The notion of ``object'' can be enlarged to include not only
499: non-textual elements, but also certain types of textual elements which can
500: appear in practically every document, whatever their class. Among these
1.2 cvs 501: textual elements, one can mention enumerations, descriptions, examples,
502: quotations, even paragraphs.</P>
1.1 cvs 503: <P>
504: Thus, the document model is not a single, general model describing every type
505: of document in one place. Rather, it is a meta-model which can be used to
506: describe many different models each of which represents either a class of
507: similar documents or a class of similar objects which every document can
508: include.</P>
509: </DIV>
510: <HR>
511: </DIV>
512:
513: <DIV class="chapter">
1.6 cvs 514: <H1><A name=sect3>The S language</A></H1>
1.1 cvs 515:
516:
517: <DIV class="section">
1.6 cvs 518: <H2><A name=sectb31>Document meta-structure</A></H2>
1.1 cvs 519:
520: <P>
521: Since the concept of meta-structure is well suited to the task of describing
522: documents at a high level of abstraction, this meta-structure must be
523: precisely defined. Toward that end this section first presents the basic
524: elements from which documents and structured objects are composed and then
525: specifies the ways in which these basic elements are assembled into structures
526: representing complete documents and objects.</P>
527:
528: <DIV class="subsection">
1.6 cvs 529: <H3><A name=sectc311>The basic types</A></H3>
1.1 cvs 530:
531: <P>
532: At the lowest level of a document's structure, the first atom considered is
533: the character. However, since characters are seldom isolated, usually
534: appearing as part of a linear sequence, and in order to reduce the complexity
535: of the document structure, <EM>character strings</EM> are used as atoms and
536: consecutive characters belonging to the same structural element are grouped in
537: the same character string.</P>
538: <P>
539: If the structure of a document is not refined to go down to the level of
540: words or phrases, the contents of a simple paragraph can be considered to be a
541: single character string. On the other hand, the title of a chapter, the title
542: of the first section of that chapter, and the text of the first paragraph of
543: that section constitute three different character strings, because they belong
544: to distinct structural elements.</P>
545: <P>
546: If, instead, a very fine-grained representation for the structure of a
547: document is sought, character strings could be defined to contain only a
548: single word, or even just a single character. This is the case, for example,
549: in programs, for which one wants to retain a structure very close to the
1.2 cvs 550: syntax of the programming language. In this case, an assignment statement
1.1 cvs 551: initializing a simple variable to zero would be composed of two structural
552: elements, the identifier of the variable (a short character string) and the
553: assigned value (a string of a single character, `0').</P>
554: <P>
555: The character string is not the only atom necessary for representing those
556: documents that interest us. It suffices for purely textual documents, but as
557: soon as the non-textual objects which we have considered arise, there must be
558: other atoms; the number of objects which are to be represented determines the
559: number of types of atoms that are necessary.</P>
560: <P>
561: Primitive <EM>graphical elements</EM> are used for tables and figures of
562: different types. These elements are simple geometric shapes like horizontal
563: or vertical lines, which are sufficient for tables, or even oblique lines,
1.2 cvs 564: arrows, rectangles, circles, polygons, and curves for use in figures. From
565: these elements and character strings, graphical objects and tables can be
566: constructed.</P>
1.1 cvs 567: <P>
568: Photographs, though having very little structure, must still appear in
1.2 cvs 569: documents. They are supported by <EM>picture</EM> elements, which are
570: represented as matrices of pixels.</P>
1.1 cvs 571: <P>
572: Finally, mathematical notations require certain elements which are
573: simultaneously characters and graphical elements, the <EM>symbols</EM>. By way
1.2 cvs 574: of example, radicals, integration signs, or even large parentheses are
1.1 cvs 575: examples of this type of atom. The size of each of these symbols is
576: determined by its environment, that is to say, by the expression to which it
577: is attached.</P>
578: <P>
579: To summarize, the primitive elements which are used in the construction of
580: documents and structured objects are:</P>
581: <UL>
582: <LI>character strings,
583: <LI>graphical elements,
1.2 cvs 584: <LI>pictures,
1.1 cvs 585: <LI>and mathematical symbols.
586: </UL>
587: </DIV>
588:
589: <DIV class="subsection">
1.6 cvs 590: <H3><A name=sectc312>Constructed elements</A></H3>
1.1 cvs 591:
592: <P>
593: A document is evidently formed from primitive elements. But the model of Thot
594: also proposes higher level elements. Thus, in a document composed of several
595: chapters, each chapter is an element, and in the chapters each section is also
596: an element, and so on. A document is thus an organized set of elements.</P>
597: <P>
598: In a document there are different sorts of elements. Each element has a
599: <EM>type</EM> which indicates the role of the element within the document as a
600: whole. Thus, we have, for example, the chapter and section types. The
601: document is made up of typed elements: elements of the type chapter and
602: elements of the type section, among others, but also character string elements
603: and graphical elements: the primitive elements are typed elements just as
604: well. At the other extreme, the document itself is also considered to be a
605: typed element.</P>
606: <P>
607: The important difference between the primitive elements and the other elements
608: of the document is that the primitive elements are atoms (they cannot be
609: decomposed), whereas the others, called <EM>constructed elements</EM>, are
610: composed of other elements, which can either be primitive elements or
611: constructed elements. A constructed element of type chapter (or more simply,
612: ``a chapter'') is composed of sections, which are also constructed elements. A
613: paragraph, a constructed element, can be made up of character strings, which
614: are primitive elements, and of equations, which are constructed elements.</P>
615: <P>
616: A document is also a constructed element. This is an important point. In
617: particular, it allows a document to be treated as part of another document,
618: and conversely, permits a part of a document to be treated as a complete
619: document. Thus, an article presented in a journal is treated by its author as
620: a document in itself, while the editor of the journal considers it to be part
621: of an issue. A table or a figure appearing in a document can be extracted and
622: treated as a complete document, for example to prepare transparencies for a
623: conference.</P>
624: <P>
625: These thoughts about types and constructed elements apply just as well to
626: objects as they do to documents. A table is a constructed element made up of
627: other constructed elements, rows and columns. A row is formed of cells, which
628: are also constructed elements which contain primitive elements (character
629: strings) and/or constructed elements like equations.</P>
630: </DIV>
631:
632: <DIV class="subsection">
1.6 cvs 633: <H3><A name=sectc313>Logical structure constructors</A></H3>
1.1 cvs 634:
635: <P>
636: Having defined the primitive elements and the constructed elements, it is now
637: time to define the types of organization which allow the building of
638: structures. For this, we rely on the notion of the <EM>constructor</EM>. A
639: constructor defines a way of assembling certain elements in a structure. It
640: resides at the level of the meta-structure: it does not describe the existing
641: relations in a given structure, but rather defines how elements are assembled
1.2 cvs 642: to build a structure that conforms to a model.</P>
1.1 cvs 643: <P>
644: In defining the overall organization of documents, the first two constructors
645: considered are the aggregate and the list.</P>
646:
647: <DIV class="subsubsection">
1.6 cvs 648: <H4><A name=sectd3131>Aggregate and List</A></H4>
1.1 cvs 649:
650: <P>
651: The <EM>aggregate</EM> constructor is used to define constructed element types
652: which are collections of a given number of other elements. These collections
653: may or may not be ordered. The elements may be either constructed or
654: primitive and are specified by their type. A report (that is, a constructed
655: element of the report type) has an aggregate structure. It is formed from a
656: title, an author's name, an introduction, a body, and a conclusion, making it
657: a collection of five element types. This type of constructor is found in
658: practically every document, and generally at several levels in a document.</P>
659: <P>
660: The <EM>list</EM> constructor is used to define constructed elements which are
661: ordered sequences of elements (constructed or primitive) having the same type.
662: The minimum and maximum numbers of elements for the sequence can be specified
663: in the list constructor or the number of elements can be left unconstrained.
664: The body of a report is a list of chapters and is typically required to
665: contain a minimum of two chapters (is a chapter useful if it is the only one
666: in the report?) The chapter itself can contain a list of sections, each
1.2 cvs 667: section containing a list of paragraphs. In the same way as the aggregate,
668: the list is a very frequently used constructor in every type of document.
669: However, these two constructors are not sufficient to describe every document
670: structure; thus other constructors supplement them.</P>
1.1 cvs 671: </DIV>
672:
673: <DIV class="subsubsection">
1.6 cvs 674: <H4><A name=sectd3132>Choice, Schema, and Unit</A></H4>
1.1 cvs 675:
676: <P>
677: The <EM>choice</EM> constructor is used to define the structure of an element
678: type for which one alternative is chosen from several possibilities. Thus, a
679: paragraph can be either a simple text paragraph, or an enumeration, or a
1.2 cvs 680: citation.</P>
1.1 cvs 681: <P>
682: The choice constructor indicates the complete list of possible options, which
683: can be too restrictive in certain cases, the paragraph being one such case.
684: Two constructors, <EM>unit</EM> and <EM>schema</EM>, address this
685: inconvenience. They allow more freedom in the choice of an element type. If
686: a paragraph is defined by a schema constructor, it is possible to put in the
687: place of a paragraph a table, an equation, a drawing or any other object
688: defined by another generic logical structure. It is also possible to define a
689: paragraph as a sequence of units, which could be character strings, symbols,
1.2 cvs 690: or pictures. The choice constructor alone defines a generic logical structure
1.1 cvs 691: that is relatively constrained; in contrast, using units and schemas, a very
692: open structure can be defined.</P>
693: <P>
694: The <EM>schema</EM> constructor represents an object defined by a generic
695: logical structure chosen freely from among those available.</P>
696: <P>
697: The <EM>unit</EM> constructor represents an element whose type can be either a
698: primitive type or an element type defined as a unit in the generic logical
699: structure of the document, or in another generic logical structure used in the
700: document. Such an element may be used in document objects constructed
701: according to other generic structures.</P>
702: <P>
703: Thus, for example, if a cross-reference to a footnote is defined in the
704: generic logical structure ``Article'' as a unit, a table (an object defined by
705: another generic structure) can contain cross-references to footnotes, when
706: they appear in an article. In another type of document, a table defined by
707: the same generic structure can contain other types of elements, depending on
708: the type of document into which the table is inserted. All that is needed is
709: to declare, in the generic structure for tables, that the contents of cells
710: are units. In this way, the generic structure of objects is divided up
711: between different types of documents which are able to adapt themselves to the
712: environment into which they are inserted.</P>
713: </DIV>
714:
715: <DIV class="subsubsection">
1.6 cvs 716: <H4><A name=sectd3133>Reference and Inclusion</A></H4>
1.1 cvs 717:
718: <P>
1.5 cvs 719: The <EM>reference</EM> is used to define document
1.1 cvs 720: elements that are cross-references to other elements, such as a section, a
1.2 cvs 721: chapter, a bibliographic citation, or a figure. The reference is
722: bi-directional. It can be used to access both the element being
1.1 cvs 723: cross-referenced and each of the elements which make use of the
724: cross-reference.</P>
725: <P>
726: References can be either <EM>internal</EM> or <EM>external</EM>. That is,
727: they can designate elements which appear in the same document or in another
728: document.</P>
729: <P>
730: The <EM><A name="inclusion">inclusion</A></EM> constructor is a special type
731: of reference. Like the reference, it is an internal or external bidirectional
732: link, but it is not a cross-reference. This link represents the ``live''
733: inclusion of the designated element; it accesses the most recent version of
734: that element and not a ``dead'' copy, fixed in the state in which it was found
735: at the moment the copy was made. As soon as an element is modified, all of
736: its inclusions are automatically brought up to date. It must be noted that,
1.2 cvs 737: in addition to inclusion, Thot permits the creation of ``dead'' copies.</P>
1.1 cvs 738: <P>
739: There are three types of inclusions: inclusions with full expansion,
740: inclusions with partial expansion, and inclusions without expansion. During
741: editing, inclusions without expansion are represented on the screen by the
742: name of the included document, in a special color, while inclusions with
743: expansion (full or partial) are represented by a copy (full or partial) of the
744: included element (also in a special color). The on-screen representation of a
1.6 cvs 745: partial inclusion is a <A href="#sectc3213">``skeleton''</A> image of the
1.1 cvs 746: included document.</P>
747: <P>
748: Inclusion with complete expansion can be used to include parts of the same
749: document or of other documents. Thus, it can be either an internal or an
750: external link. It can be used to include certain bibliographic entries of a
751: scientific article in another article, or to copy part of a mathematical
752: formula into another formula of the same document, thus assuring that both
753: copies will remain synchronized.</P>
754: <P>
755: Inclusion without expansion or with partial expansion is used to include
756: complete documents. It is always an external link. It is used primarily to
757: divide very large documents into sub-documents that are easier to manipulate,
758: especially when there are many authors. So, a book can include some chapters,
759: where each chapter is a different document which can be edited separately.
760: When viewing the book on the screen, it might be desirable to see only the
761: titles of the chapters and sections. This can be achieved using inclusion
762: with partial expansion.</P>
763: <P>
764: During printing, inclusions without expansion or with partial expansion can be
765: represented either as they were shown on the screen or by a complete (and
766: up-to-date) copy of the included element or document.</P>
767: <P>
768: The inclusion constructor, whatever its type, respects the generic structure:
769: only those elements authorized by the generic structure can be included at a
770: given position in a document.</P>
771: </DIV>
772:
773: <DIV class="subsubsection">
1.6 cvs 774: <H4><A name=sectd3134>Mark pairs</A></H4>
1.1 cvs 775:
776: <P>
777: It is often useful to delimit certain parts of a document independently from
778: the logical structure. For example, one might wish to attach some information
1.6 cvs 779: (in the form of an <A href="#sectc315">attribute</A>) or a particular
1.1 cvs 780: treatment to a group of words or a set of consecutive paragraphs. <EM>Mark
781: pairs</EM> are used to do this.</P>
782: <P>
783: Mark pairs are elements which are always paired and are terminals in the
784: logical structure of the document. Their position in the structure of the
785: document is defined in the generic structure. It is important to note that
786: when the terminals of a mark pair are <EM>extensions</EM> (see the next
787: section), they can be used quite freely.</P>
788: </DIV>
789:
790: <DIV class="subsubsection">
1.6 cvs 791: <H4><A name=sectd3135>Restrictions and Extensions</A></H4>
1.1 cvs 792:
793: <P>
794: The primitive types and the constructors presented so far permit the
795: definition of the logical structure of documents and objects in a rigorous
796: way. But this definition can be very cumbersome in certain cases, notably
797: when trying to constrain or extend the authorized element types in a
798: particular context. <EM>Restrictions</EM> and <EM>extensions</EM> are used to
1.2 cvs 799: cope with these cases.</P>
1.1 cvs 800: <P>
801: A restriction associates with a particular element type <EM>A</EM>, a list of
802: those element types which elements of type <EM>A</EM> may not contain, even if
803: the definition of type <EM>A</EM> and those of its components authorize them
804: otherwise. This simplifies the writing of generic logical structures and
805: allows limitations to be placed, when necessary, on the choices offered by the
806: schema and unit constructors.</P>
807: <P>
808: Extensions are the inverse of restrictions. They identify a list of element
809: types whose presence <EM>is</EM> permitted, even if its definition and those
810: of its components do not authorize them otherwise.</P>
811: </DIV>
812:
813: <DIV class="subsubsection">
1.6 cvs 814: <H4><A name=sectd3136>Summary</A></H4>
1.1 cvs 815:
816: <P>
817: Thus, four constructors are used to construct a document:</P>
818: <UL>
1.2 cvs 819: <LI>the aggregate constructor (ordered or not),
1.1 cvs 820: <LI>the list constructor,
1.2 cvs 821: <LI>the choice constructor and its extensions, the unit and schema
822: constructors,
1.1 cvs 823: <LI>the reference constructor and its variant, the inclusion.
824: </UL>
825: <P>
826: These constructors are also sufficient for objects. Thus, these constructors
827: provide a homogenous meta-model which can describe both the organization of
828: the document as a whole and that of the various types of objects which it
829: contains. After presenting the description language for generic structures,
830: we will present several examples which illustrate the appropriateness of the
831: model.</P>
832: <P>
833: The first three constructors (aggregate, list and choice) lead to tree-like
834: structures for documents and objects, the objects being simply the subtrees of
835: the tree of a document (or even of other objects' subtrees). The reference
836: constructor introduces other, non-hierarchical, relations which augment those
837: of the tree: when a paragraph makes reference to a chapter or a section, that
838: relation leaves the purely tree-like structure. Moreover, external reference
839: and inclusion constructors permit the establishment of links between different
840: documents, thus creating a hypertext structure.</P>
841: </DIV>
842: </DIV>
843:
844: <DIV class="subsection">
1.6 cvs 845: <H3><A name=sectc314>Associated Elements</A></H3>
1.1 cvs 846:
847: <P>
848: Thanks to the list, aggregate and choice constructors, the organization of the
849: document is specified rigorously, using constructed and primitive elements.
850: But a document is made up of more than just its elements; it clearly also
851: contains links between them. There exist elements whose position in the
852: document's structure is not determinable. This is notably the case for
853: figures and notes. A figure can be designated at many points in the same
854: document and its place in the physical document can vary over the life of the
855: document without any effect on the meaning or clarity of the document. At one
856: time, it can be placed at the end of the document along with all other
857: figures. At another time, it can appear at the top of the page which follows
858: the first mention of the figure. The figures can be dispersed throughout the
859: document or can be grouped together. The situation is similar for notes,
860: which can be printed at the bottom of the page on which they are mentioned or
861: assembled together at the end of the chapter or even the end of the work. Of
862: course, this brings up questions of the physical position of elements in
863: documents that are broken into pages, but this reflects the structural
864: instability of these elements. They cannot be treated the same way as
865: elements like paragraphs or sections, whose position in the structure is
866: directly linked to the semantics of the document.</P>
867: <P>
868: Those elements whose position in the structure of the document is not fixed,
869: even though they are definitely part of the document, are called
870: <EM>associated elements</EM>. Associated elements are themselves structures,
871: which is to say that their content can be organized logically by the
872: constructors from primitive and constructed elements.</P>
873: <P>
874: It can happen that the associated elements are totally disconnected from the
875: structure of the document, as in a commentary or appraisal of the entire work.
876: But more often, the associated elements are linked to the content of the
877: document by references. This is generally the case for notes and figures,
878: among others.</P>
879: <P>
880: Thus, associated elements introduce a new use for the reference constructor.
881: It not only serves to create links between elements of the principal structure
882: of the document, but also serves to link the associated elements to the
883: primary structure.</P>
884: </DIV>
885:
886: <DIV class="subsection">
1.6 cvs 887: <H3><A name=sectc315>Attributes</A></H3>
1.1 cvs 888:
889: <P>
890: There remain logical aspects of documents that are not entirely described by
891: the structure. Certain types of semantic information, which are not stated
892: explicitly in the text, must also be taken into account. In particular, such
893: information is shown by typographic effects which do not correspond to a
894: change between structural elements. In fact, certain titles are set in bold
895: or italic or are printed in a different typeface from the rest of the text in
896: order to mark them as structurally distinct. But these same effects
897: frequently appear in the middle of continuous text (e.g. in the interior of a
898: paragraph). In this case, there is no change between structural elements; the
899: effect serves to highlight a word, expression, or phrase. The notion of an
900: <EM>attribute</EM> is used to express this type of information.</P>
901: <P>
902: An attribute is a piece of information attached to a structural element which
903: augments the type of the element and clarifies its function in the document.
904: Keywords, foreign language words, and titles of other works can all be
905: represented by character strings with attached attributes. Attributes may
906: also be attached to constructed elements. Thus, an attribute indicating the
907: language can be attached to a single word or to a large part of a
908: document.</P>
909: <P>
910: In fact, an attribute can be any piece of information which is linked to a
911: part of a document and which can be used by agents which work on the document.
912: For example, the language in which the document is written determines the set
913: of characters used by an editor or formatter. It also determines the
914: algorithm or hyphenation dictionary to be used. The attribute ``keyword''
915: facilitates the work of an information retrieval system. The attribute
916: ``index word'' allows a formatter to automatically construct an index at the
917: end of the document.</P>
918: <P>
919: As with the types of constructed elements, the attributes and the values they
920: can take are defined separately in each generic logical structure, not in the
921: meta-model, according to the needs of the document class or the nature of the
922: object.</P>
923: <P>
924: Many types of attributes are offered: numeric, textual, references, and
925: enumerations:</P>
926: <UL>
1.2 cvs 927: <LI><EM>Numeric attributes</EM> can take integer values (negative, positive,
928: or null).
1.1 cvs 929: <LI><EM>Textual attributes</EM> have as their values character strings.
1.2 cvs 930: <LI><EM>Reference attributes</EM> designate an element of the logical
931: structure.
932: <LI><EM>Enumeration attributes</EM> can take one value from a limited list of
1.1 cvs 933: possible values, each value being a name.
934: </UL>
935: <P>
936: In a generic structure, there is a distinction between <EM>global
937: attributes</EM> and <EM>local attributes</EM>. A global attribute can be
938: applied to every element type defined in the generic structure where it is
939: specified. In contrast, a local attribute can only be applied to certain
940: types of elements, even only a single type. The ``language'' attribute
941: presented above is an example of a global attribute. An example of a local
942: attribute is the rank of an author (principal author of the document or
943: secondary author): this attribute can only be applied sensibly to an element
944: of the ``author'' type.</P>
945: <P>
946: Attributes can be assigned to the elements which make up the document in many
947: different ways. The author can freely and dynamically place them on any part
1.5 cvs 948: of the document in order to attach supplementary information of his/her choice.
1.1 cvs 949: However, attributes may only be assigned in accordance with the rules of the
950: generic structure; in particular, local attributes can only be assigned to
951: those element types for which they are defined.</P>
952: <P>
953: In the generic structure, certain local attributes can be made mandatory for
1.2 cvs 954: certain element types. In this case, Thot automatically associates the
955: attribute with the elements of this type and it requires the user to provide a
956: value for this attribute.</P>
1.1 cvs 957: <P>
958: Attributes can also be automatically assigned, with a given value, by every
959: application processing the document in order to systematically add a piece of
960: information to certain predefined elements of the document. By way of
961: example, in a report containing a French abstract and an English abstract,
962: each of the two abstracts is defined as a sequence of paragraphs. The first
963: abstract has a value of ``French'' for the ``language'' attribute while the
964: second abstract's ``language'' attribute has a value of ``English''.</P>
965: <P>
966: In the case of mark pairs, attributes are logically associated with the pair
967: as a whole, but are actually attached to the first mark.</P>
968: </DIV>
969:
970: <DIV class="subsection">
1.6 cvs 971: <H3><A name=sectc316>Discussion of the model</A></H3>
1.1 cvs 972:
973: <P>
974: The notions of attribute, constructor, structured element, and associated
975: element are used in the definition of generic logical structures of documents
976: and objects. The problem is to assemble them to form generic structures. In
977: fact, many types of elements and attributes can be found in a variety of
978: generic structures. Rather than redefine them for each structure in which
979: they appear, it is best to share them between structures. The object classes
980: already fill this sharing function. If a mathematical class is defined, its
981: formulas can be used in many different document classes, without redefining
982: the structure of each class. This problem arises not only for the objects
983: considered here; it also arises for the commonplace textual elements found in
984: many document classes. This is the reason why the notion of object is so
985: broad and why paragraphs and enumerations are also considered to be objects.
986: These object classes not only permit the sharing of the structures of
987: elements, but also of the attributes defined in the generic structures.</P>
988: <P>
989: Structure, such as that presented here, can appear very rigid, and it is
990: possible to imagine that a document editing system based on this model could
991: prove very constraining to the user. This is, in fact, a common criticism of
992: syntax-directed editors. This defect can be avoided with Thot, primarily for
993: three reasons:</P>
994: <UL>
995: <LI>the generic structures are not fixed in the model itself,
996: <LI>the model takes the dynamics of documents into account,
997: <LI>the constructors offer great flexibility.
998: </UL>
999: <P>
1000: When the generic structure of a document is not predefined, but rather is
1001: constructed specifically for each document class, it can be carefully adapted
1002: to the current needs. In cases where the generic structure is inadequate for
1003: a particular document of the class, it is always possible either to create a
1004: new class with a generic structure well suited to the new case or to extend
1005: the generic structure of the existing class to take into account the specifics
1006: of the document which poses the problem. These two solutions can also be
1007: applied to objects whose structures prove to be poorly designed.</P>
1008: <P>
1009: The model is sufficiently flexible to take into account all the phases of the
1010: life of the document. When a generic structure specifies that a report must
1011: contain a title, an abstract, an introduction, at least two chapters, and a
1012: conclusion, this means only that a report, <EM>upon completion</EM>, will have
1013: to contain all of these elements. When the author begins writing, none of
1.2 cvs 1014: these elements is present. Thot uses this model. Therefore, it tolerates
1015: documents which do not conform strictly to the generic structure of their
1016: class; it also considers the generic logical structure to be a way of helping
1017: the user in the construction of a complex document.</P>
1.1 cvs 1018: <P>
1019: In contrast, other applications may reject a document which does not conform
1020: strictly to its generic structure. This is, for example, what is done by
1021: compilers which refuse to generate code for a program which is not
1022: syntactically correct. This might also occur when using a document
1023: application for a report which does not have an abstract or title.</P>
1024: <P>
1025: The constructors of the document model bring a great flexibility to the
1026: generic structures. A choice constructor (and even more, a unit or schema
1027: constructor) can represent several, very different elements. The list
1028: constructor permits the addition of more elements of the same type. Used
1029: together, these two constructors permit any series of elements of different
1030: types. Of course, this flexibility can be reduced wherever necessary since a
1031: generic structure can limit the choices or the number of elements in a
1032: list.</P>
1033: <P>
1034: Another difficulty linked to the use of structure in the document model
1035: resides in the choice of the level of the structure. The structure of a
1036: discussion could be extracted from the text itself via linguistic analysis.
1037: Some studies are exploring this approach, but the model of Thot excludes this
1038: type of structure. It only takes into account the logical structure provided
1039: explicitly by the author.</P>
1040: <P>
1041: However, the level of structure of the model is not imposed. Each generic
1042: structure defines its own level of structure, adapted to the document class or
1043: object and to the ways in which it will be processed. If it will only be
1044: edited and printed, a relatively simple structure suffices. If more
1045: specialized processing will be applied to it, the structure must represent the
1046: element types on which this processing must act. By way of example, a simple
1047: structure is sufficient for printing formulas, but a more complex structure is
1048: required to perform symbolic or numeric calculations on the mathematical
1049: expressions. The document model of Thot allows both types of structure.</P>
1050: </DIV>
1051: </DIV>
1052:
1053: <DIV class="section">
1.6 cvs 1054: <H2><A name=sectb32>The definition language for generic structures</A></H2>
1.1 cvs 1055:
1056: <P>
1057: Generic structures, which form the basis of the document model of Thot, are
1058: specified using a special language. This definition language, called S, is
1059: described in this section.</P>
1060: <P>
1061: Each generic structure, which defines a class of documents or objects, is
1.2 cvs 1062: specified by a file, written in the S language, which is called a
1.1 cvs 1063: <EM>structure schema</EM>. Structure schemas are compiled into tables, called
1.2 cvs 1064: structure tables, which are used by Thot and which determine its behavior.</P>
1.1 cvs 1065:
1066: <DIV class="subsection">
1.6 cvs 1067: <H3><A name=sectc321>Writing Conventions</A></H3>
1.1 cvs 1068:
1069: <P>
1070: The grammar of S, like those of the languages P and T presented later, is
1071: described using the meta-language M, derived from the Backus-Naur Form
1072: (BNF).</P>
1073: <P>
1074: In this meta-language each rule of the grammar is composed of a grammar symbol
1075: followed by an equals sign (`=') and the right part of the rule. The equals
1076: sign plays the same role as the traditional `::=' of BNF: it indicates that
1077: the right part defines the symbol of the left part. In the right part,</P>
1078: <DL>
1079: <DT>concatenation</DT>
1080: <DD>is shown by the juxtaposition of symbols;
1081: </DD>
1082: <DT>character strings</DT>
1.2 cvs 1083: <DD>between apostrophes ' represent terminal symbols, that is, keywords in the
1084: language defined. Keywords are written here in upper-case letters, but can be
1085: written in any combination of upper and lower-case letters. For example, the
1086: keyword <TT>DEFPRES</TT> of S can also be written as <TT>defpres</TT> or
1087: <TT>DefPres</TT>.
1.1 cvs 1088: </DD>
1089: <DT>material between brackets</DT>
1090: <DD>(`[' and `]') is optional;
1091: </DD>
1092: <DT>material between angle brackets</DT>
1.2 cvs 1093: <DD>(`<' and `>') can be repeated many times or omitted;
1.1 cvs 1094: </DD>
1095: <DT>the slash</DT>
1.2 cvs 1096: <DD>(`/') indicates an alternative, a choice between the options separated by
1.1 cvs 1097: the slash character;
1098: </DD>
1099: <DT>the period</DT>
1100: <DD>marks the end of a rule;
1101: </DD>
1102: <DT>text between braces</DT>
1103: <DD>(`{' and `}') is simply a comment.
1104: </DD>
1105: </DL>
1106: <P>
1107: The M meta-language also uses the concepts of identifiers, strings, and
1108: integers:</P>
1109: <DL>
1110: <DT><TT>NAME</TT></DT>
1.2 cvs 1111: <DD>represents an identifier, a sequence of letters (upper or lower-case),
1112: digits, and underline characters (`_'), beginning with a letter. Also
1113: considered a letter is the sequence of characters `<TT>\nnn</TT>' where the
1.5 cvs 1114: letter <TT>n</TT> represents the ISO Latin-1 code of the letter in octal. It
1.2 cvs 1115: is thus possible to use accented letters in identifiers. The maximum length
1116: of identifiers is fixed by the compiler. It is normally 31 characters.
1.1 cvs 1117: <P>
1118: Unlike keywords, upper and lower-case letters are distinct in identifiers.
1119: Thus, <TT>Title</TT>, <TT>TITLE</TT>, and <TT>title</TT> are considered
1120: different identifiers.</P>
1121: </DD>
1122: <DT><TT>STRING</TT></DT>
1.2 cvs 1123: <DD>represents a string. This is a string of characters delimited by
1124: apostrophes. If an apostrophe must appear in a string, it is doubled. As
1125: with identifiers, strings can contain characters represented by their octal
1126: code (after a backslash). As with apostrophes, if a backslash must appear in
1127: a string, it is doubled.
1.1 cvs 1128: </DD>
1129: <DT><TT>NUMBER</TT></DT>
1.2 cvs 1130: <DD>represents a positive integer or zero (without a sign), or said another
1.1 cvs 1131: way, a sequence of decimal digits.
1132: </DD>
1133: </DL>
1134: <P>
1135: The M language can be used to define itself as follows:</P>
1136: <PRE>
1137: { Any text between braces is a comment. }
1138: Grammar = Rule < Rule > 'END' .
1139: { The < and > signs indicate zero }
1140: { or more repetitions. }
1141: { END marks the end of the grammar. }
1142: Rule = Ident '=' RightPart '.' .
1143: { The period indicates the end of a rule }
1144: RightPart = RtTerminal / RtIntermed .
1145: { The slash indicates a choice }
1146: RtTerminal ='NAME' / 'STRING' / 'NUMBER' .
1147: { Right part of a terminal rule }
1148: RtIntermed = Possibility < '/' Possibility > .
1149: { Right part of an intermediate rule }
1150: Possibility = ElemOpt < ElemOpt > .
1151: ElemOpt = Element / '[' Element < Element > ']' /
1152: '<' Element < Element > '>' .
1153: { Brackets delimit optional parts }
1154: Element = Ident / KeyWord .
1155: Ident = NAME .
1156: { Identifier, sequence of characters }
1157: KeyWord = STRING .
1158: { Character string delimited by apostrophes }
1159: END
1160: </PRE>
1161: </DIV>
1162:
1163: <DIV class="subsection">
1.6 cvs 1164: <H3><A name=sectc322>Extension schemas</A></H3>
1.1 cvs 1165:
1166: <P>
1167: A structure schema defines the generic logical structure of a class of
1168: documents or objects, independent of the operations which can be performed on
1169: the documents. However, certain applications may require particular
1170: information to be represented by the structure for the documents that they
1171: operate on. Thus a document version manager will need to indicate in the
1172: document the parts which belong to one version or another. An indexing system
1173: will add highly-structured index tables as well as the links between these
1174: tables and the rest of the document.</P>
1175: <P>
1.2 cvs 1176: Thus, many applications need to extend the generic structure of the documents
1177: on which they operate to introduce new attributes, associated elements or
1.1 cvs 1178: element types. These additions are specific to each application and must be
1179: able to be applied to any generic structure: users will want to manage
1180: versions or construct indices for many types of documents. Extension schemas
1181: fulfill this role: they define attributes, elements, associated elements,
1182: units, etc., but they can only be used jointly with a structure schema that
1183: they complete. Otherwise, structure schemas can always be used without these
1184: extensions when the corresponding applications are not available.</P>
1185: </DIV>
1186:
1187: <DIV class="subsection">
1.6 cvs 1188: <H3><A name=sectc323>The general organization of structure schemas</A></H3>
1.1 cvs 1189:
1190: <P>
1191: Every structure schema begins with the keyword <TT>STRUCTURE</TT> and ends
1192: with the keyword <TT>END</TT>. The keyword <TT>STRUCTURE</TT> is followed by
1193: the keyword <TT>EXTENSION</TT> in the case where the schema defines an
1194: extension, then by the name of the generic structure which the schema defines
1195: (the name of the document or object class). The name of the structure is
1196: followed by a semicolon.</P>
1197: <P>
1198: In the case of a complete schema (that is, a schema which is not an
1199: extension), the definition of the name of the structure is followed by the
1200: declarations of the default presentation schema, the global attributes, the
1201: parameters, the structure rules, the associated elements, the units, the
1202: skeleton elements and the exceptions. Only the definition of the structure
1203: rules is required. Each series of declarations begins with a keyword:
1204: <TT>DEFPRES</TT>, <TT>ATTR</TT>, <TT>PARAM</TT>, <TT>STRUCT</TT>,
1205: <TT>ASSOC</TT>, <TT>UNITS</TT>, <TT>EXPORT</TT>, <TT>EXCEPT</TT>.</P>
1206: <P>
1207: In the case of an extension schema, there are neither parameters nor skeleton
1208: elements and the <TT>STRUCT</TT> section is optional, while that section is
1209: required in a schema that is not an extension. On the other hand, extension
1210: schemas can contain an <TT>EXTENS</TT> section, which must not appear in a
1211: schema which is not an extension; this section defines the complements to
1212: attach to the rules found in the schema to which the extension will be added.
1213: The sections <TT>ATTR</TT>, <TT>STRUCT</TT>, <TT>ASSOC</TT>, and
1214: <TT>UNITS</TT> define new attributes, new elements, new associated elements,
1215: and new units which add their definitions to the principal schema.</P>
1216: <PRE>
1217: StructSchema ='STRUCTURE' ElemID ';'
1218: 'DEFPRES' PresID ';'
1219: [ 'ATTR' AttrSeq ]
1220: [ 'PARAM' RulesSeq ]
1221: 'STRUCT' RulesSeq
1222: [ 'ASSOC' RulesSeq ]
1223: [ 'UNITS' RulesSeq ]
1224: [ 'EXPORT' SkeletonSeq ]
1225: [ 'EXCEPT' ExceptSeq ]
1226: 'END' .
1227: ElemID = NAME .
1228: </PRE>
1229: <P>
1230: or</P>
1231: <PRE>
1232: ExtensSchema ='STRUCTURE' 'EXTENSION' ElemID ';'
1233: 'DEFPRES' PresID ';'
1234: [ 'ATTR' AttrSeq ]
1235: [ 'STRUCT' RulesSeq ]
1236: [ 'EXTENS' ExtensRuleSeq ]
1237: [ 'ASSOC' RulesSeq ]
1238: [ 'UNITS' RulesSeq ]
1239: [ 'EXCEPT' ExceptSeq ]
1240: 'END' .
1241: ElemID = NAME .
1242: </PRE>
1243: </DIV>
1244:
1245: <DIV class="subsection">
1.6 cvs 1246: <H3><A name=sectc324>The default presentation</A></H3>
1.1 cvs 1247:
1248: <P>
1249: It was shown <A href="#mulpres">above</A> that many different presentations
1250: are possible for documents and objects of the same class. The structure
1251: schema defines a preferred presentation for the class, called the <EM>default
1252: presentation</EM>. Like generic structures, presentations are described by
1253: programs, called <EM>presentation schemas</EM>, which are written in a
1.6 cvs 1254: specific language, P, presented <A href="#sectb42">later</A> in this document.
1.1 cvs 1255: The name appearing after the keyword <TT>DEFPRES</TT> is the name of the
1.2 cvs 1256: default presentation schema. When a new document is created, Thot will use
1257: this presentation schema by default, but the user remains free to choose
1.5 cvs 1258: another if s/he wishes.</P>
1.1 cvs 1259: <PRE>
1260: PresID = NAME .
1261: </PRE>
1262: </DIV>
1263:
1264: <DIV class="subsection">
1.6 cvs 1265: <H3><A name=sectc325>Global Attributes</A></H3>
1.1 cvs 1266:
1267: <P>
1268: If the generic structure includes global attributes of its own, they are
1269: declared after the keyword <TT>ATTR</TT>. Each global attribute is defined by
1270: its name, followed by an equals sign and the definition of its type. The
1271: declaration of a global attribute is terminated by a semi-colon.</P>
1272: <P>
1273: For attributes of the numeric, textual, or reference types, the type is
1274: indicated by a keyword, <TT>INTEGER</TT>, <TT>TEXT</TT>, or <TT>REFERENCE</TT>
1275: respectively.</P>
1276: <P>
1277: In the case of a reference attribute, the keyword <TT>REFERENCE</TT> is
1278: followed by the type of the referenced element in parentheses. It can refer
1279: to any type at all, specified by using the keyword <TT>ANY</TT>, or to a
1280: specific type. In the latter case, the element type designated by the
1.6 cvs 1281: reference can be defined either in the <A href="#sectc327"><TT>STRUCT</TT>
1.1 cvs 1282: section</A> of the same structure schema or in the <TT>STRUCT</TT> section of
1283: another structure schema. When the type is defined in another schema, the
1284: element type is followed by the name of the structure schema (within
1285: parentheses) in which it is defined. The name of the designated element type
1286: can be preceded by the keyword <TT>First</TT> or <TT>Second</TT>, but only in
1.6 cvs 1287: the case where the type is defined as <A href="#sectd3285">a pair</A>. These
1.1 cvs 1288: keywords indicate whether the attribute must designate the first mark of the
1289: pair or the second. If the reference refers to a pair and neither of these
1290: two keywords is present, then the first mark is used.</P>
1291: <P>
1292: In the case of an enumeration attribute, the equals sign is followed by the
1293: list of names representing the possible values of the attribute, the names
1294: being separated from each other by commas. An enumeration attribute has at
1295: least one possible value; the maximum number of values is defined by the
1296: compiler for the S language.</P>
1297: <PRE>
1298: AttrSeq = Attribute < Attribute > .
1299: Attribute = AttrID '=' AttrType ';' .
1300: AttrType = 'INTEGER' / 'TEXT' /
1301: 'REFERENCE' '(' RefType ')' /
1302: ValueSeq .
1303: RefType = 'ANY' / [ FirstSec ] ElemID [ ExtStruct ] .
1304: FirstSec = 'First' / 'Second' .
1305: ExtStruct = '(' ElemID ')' .
1306: ValueSeq = AttrVal < ',' AttrVal > .
1307: AttrID = NAME .
1308: AttrVal = NAME .
1309: </PRE>
1310: <P>
1311: There is a predefined global text attribute, the <EM>language</EM>, which is
1.2 cvs 1312: automatically added to every Thot structure schema. This attribute allows
1313: Thot to perform certain actions, such as hyphenation and spell-checking, which
1314: cannot be performed without knowing the language in which each part of the
1315: document is written. This attribute can be used just like any explicitly
1.1 cvs 1316: declared attribute: the system acts as if every structure schema contains</P>
1317: <PRE>
1318: ATTR
1319: Language = TEXT;
1320: </PRE>
1321: <BLOCKQUOTE class="example">
1322: <P>
1323: <STRONG>Example:</STRONG></P>
1324: <P>
1.2 cvs 1325: The following specification defines the global enumeration attribute
1326: WordType.</P>
1.1 cvs 1327: <PRE>
1328: ATTR
1.6 cvs 1329: WordType = Definition, IndexWord, DocumentTitle;
1.1 cvs 1330: </PRE>
1331: </BLOCKQUOTE>
1332: </DIV>
1333:
1334: <DIV class="subsection">
1.6 cvs 1335: <H3><A name=sectc326>Parameters</A></H3>
1.1 cvs 1336:
1337: <P>
1338: A parameter is a document element which can appear many times in the document,
1339: but always has the same value. This value can only be modified in a
1340: controlled way by certain applications. For example, in an advertising
1341: circular, the name of the recipient may appear in the address part and in the
1342: text of the circular. If the recipient's name were a parameter, it might only
1343: be able to be changed by a ``mail-merge'' application.</P>
1344: <P>
1345: Parameters are not needed for every document class, but if the schema includes
1346: parameters they are declared after the keyword <TT>PARAM</TT>. Each parameter
1.6 cvs 1347: declaration is made in the same way as a <A href="#sectc327">structure
1.1 cvs 1348: element declaration</A>.</P>
1349: <P>
1350: During editing, Thot permits the insertion of parameters wherever the
1351: structure schema allows; it also permits the removal of parameters which are
1352: already in the document but does not allow the modification of the parameter's
1.2 cvs 1353: content in any way. The content is generated automatically by Thot during the
1354: creation of the parameter, based on the value of the parameter in the
1355: document.</P>
1.1 cvs 1356: </DIV>
1357:
1358: <DIV class="subsection">
1.6 cvs 1359: <H3><A name=sectc327>Structured elements</A></H3>
1.1 cvs 1360:
1361: <P>
1362: The rules for defining structured elements are required, except in an
1363: extension schema: they constitute the core of a structure schema, since they
1364: define the structure of the different types of elements that occur in a
1365: document or object of the class defined by the schema.</P>
1366: <P>
1367: The first structure rule after the keyword <TT>STRUCT</TT> must define the
1368: structure of the class whose name appears in the first instruction
1369: (<TT>STRUCTURE</TT>) of the schema. This is the root rule of the schema,
1370: defining the root of the document tree or object tree.</P>
1371: <P>
1372: The remaining rules may be placed in any order, since the language permits the
1373: definition of element types before or after their use, or even in the same
1374: instruction in which they are used. This last case allows the definition of
1375: recursive structures.</P>
1376: <P>
1377: Each rule is composed of a name (the name of the element type whose structure
1378: is being defined) followed by an equals sign and a structure definition.</P>
1379: <P>
1380: If any local attributes are associated with the element type defined by the
1.2 cvs 1381: rule, they appear between parentheses after the type name and before the
1382: equals sign. The parentheses contain, first, the keyword <TT>ATTR</TT>, then
1383: the list of local attributes, separated by commas. Each local attribute is
1384: composed of the name of the attribute followed by an equals sign and the
1385: definition of the attribute's type, just as in the definition of <A
1.6 cvs 1386: href="#sectc325">global attributes</A>. The name of the attribute can be
1.2 cvs 1387: preceded by an exclamation point to indicate that the attribute must always be
1388: present for this element type. The same attribute, identified by its name,
1389: can be defined as a local attribute for multiple element types. In this
1390: case, the equals sign and definition of the attribute type need only appear in
1391: the first occurrence of the attribute. It should be noted that global
1392: attributes cannot also be defined as local attributes.</P>
1.1 cvs 1393: <P>
1.6 cvs 1394: If any <A href="#sectd3135">extensions</A> are defined for this
1.1 cvs 1395: element type, a plus sign follows the structure definition and the names of
1396: the extension element types appear between parentheses after the plus. If
1397: there are multiple extensions, they are separated by commas. These types can
1398: either be defined in the same schema, defined in other schemas, or they may be
1399: base types identified by the keywords <TT>TEXT</TT>, <TT>GRAPHICS</TT>,
1400: <TT>SYMBOL</TT>, or <TT>PICTURE</TT>.</P>
1401: <P>
1.6 cvs 1402: <A href="#sectd3135">Restrictions</A> are indicated in the same
1.1 cvs 1403: manner as extensions, but they are introduced by a minus sign and they come
1404: after the extensions, or if there are no extensions, after the structure
1405: definition.</P>
1406: <P>
1407: If the values of attributes must be attached systematically to this element
1408: type, they are introduced by the keyword <TT>WITH</TT> and declared in the
1409: form of a list of fixed-value attributes. When such definitions of fixed
1410: attribute values appear, they are always the last part of the rule.</P>
1411: <P>
1412: The rule is terminated by a semicolon.</P>
1413: <PRE>
1414: RuleSeq = Rule < Rule > .
1415: Rule = ElemID [ LocAttrSeq ] '=' DefWithAttr ';'.
1416: LocAttrSeq = '(' 'ATTR' LocAttr < ';' LocAttr > ')' .
1417: LocAttr = [ '!' ] AttrID [ '=' AttrType ] .
1418: DefWithAttr = Definition
1419: [ '+' '(' ExtensionSeq ')' ]
1420: [ '-' '(' RestrictSeq ')' ]
1421: [ 'WITH' FixedAttrSeq ] .
1422: ExtensionSeq = ExtensionElem < ',' ExtensionElem > .
1423: ExtensionElem = ElemID / 'TEXT' / 'GRAPHICS' /
1424: 'SYMBOL' / 'PICTURE' .
1425: RestrictSeq = RestrictElem < ',' RestrictElem > .
1426: RestrictElem = ElemID / 'TEXT' / 'GRAPHICS' /
1427: 'SYMBOL' / 'PICTURE' .
1428: </PRE>
1429: <P>
1430: The list of fixed-value attributes is composed of a sequence of
1431: attribute-value pairs separated by commas. Each pair contains the name of the
1432: attribute and the fixed value for this element type, the two being separated
1433: by an equals sign. If the sign is preceded by a question mark the given value
1434: is only an initial value that may be modified later rather than a value fixed
1435: for all time. Reference attributes are an exception to this norm. They
1436: cannot be assigned a fixed value, but when the name of such an attribute
1437: appears this indicates that this element type must have a valid value for the
1.2 cvs 1438: attribute. For the other attribute types, the fixed value is indicated by a
1.1 cvs 1439: signed integer (numeric attributes), a character string between apostrophes
1440: (textual attributes) or the name of a value (enumeration attributes).</P>
1441: <P>
1.6 cvs 1442: Fixed-value attributes can either be <A href="#sectc325">global</A> or local
1.1 cvs 1443: to the element type for which they are fixed, but they must be declared before
1444: they are used.</P>
1445: <PRE>
1446: FixedAttrSeq = FixedAttr < ',' FixedAttr > .
1447: FixedAttr = AttrID [ FixedOrModifVal ] .
1448: FixedOrModifVal = [ '?' ] '=' FixedValue .
1449: FixedValue = [ '-' ] NumValue / TextVal / AttrVal .
1450: NumValue = NUMBER .
1451: TextVal = STRING .
1452: </PRE>
1453: </DIV>
1454:
1455: <DIV class="subsection">
1.6 cvs 1456: <H3><A name=sectc328>Structure definitions</A></H3>
1.1 cvs 1457:
1458: <P>
1459: The structure of an element type can be a simple base type or a constructed
1460: type.</P>
1461: <P>
1462: For constructed types, it is frequently the case that similar structures
1463: appear in many places in a document. For example the contents of the
1464: abstract, of the introduction, and of a section can have the same structure,
1465: that of a sequence of paragraphs. In this case, a single, common structure
1466: can be defined (the paragraph sequence in this example), and the schema is
1467: written to indicate that each element type possesses this structure, as
1468: follows:</P>
1469: <PRE>
1470: Abstract = Paragraph_sequence;
1471: Introduction = Paragraph_sequence;
1472: Section_contents = Paragraph_sequence;
1473: </PRE>
1474: <P>
1475: The equals sign means ``has the same structure as''.</P>
1476: <P>
1477: If the element type defined is a simple base type, this is indicated by one of
1478: the keywords <TT>TEXT</TT>, <TT>GRAPHICS</TT>, <TT>SYMBOL</TT>, or
1479: <TT>PICTURE</TT>. If some local attributes must be associated with a base
1480: type, the keyword of the base type is followed by the declaration of the local
1.6 cvs 1481: attributes using the syntax <A href="#sectc327">presented above.</A></P>
1.1 cvs 1482: <P>
1483: In the case of an open choice, the type is indicated by the keyword
1.2 cvs 1484: <TT>UNIT</TT> for units or the keyword <TT>NATURE</TT> for objects having a
1485: structure defined by any other schema.</P>
1.1 cvs 1486: <P>
1487: A unit represents one of the two following categories:</P>
1488: <UL>
1.2 cvs 1489: <LI>a base type: text, graphical element, symbol, picture,
1490: <LI>an element whose type is chosen from among the types defined as units in
1.5 cvs 1491: the <TT>UNITS</TT> section of the document's structure schema. It can also be
1.6 cvs 1492: chosen from among the types defined as <A href="#sectd3132">units</A> in
1493: the <A href="#sectc3212"><TT>UNITS</TT> section</A> of the structure schemas that
1.2 cvs 1494: defines the ancestors of the element to which the rule is applied.
1.1 cvs 1495: </UL>
1496: <P>
1.2 cvs 1497: Before the creation of an element defined as a unit, Thot asks the user to
1498: choose between the categories of elements.</P>
1.1 cvs 1499: <P>
1500: Thus, the contents of a paragraph can be specified as a sequence of units,
1501: which will permit the inclusion in the paragraphs of character strings,
1502: symbols, and various elements, such as cross-references, if these are defined
1503: as units.</P>
1504: <P>
1505: A schema object (keyword <TT>NATURE</TT>) represents an object defined by a
1506: structure schema freely chosen from among the available schemas; in the case
1507: the element type is defined by the first rule (the root rule) of the chosen
1508: schema.</P>
1509: <P>
1510: If the element type defined is a constructed type, the list, aggregate,
1511: choice, and reference constructors are used. In this case the definition
1512: begins with a keyword identifying the constructor. This keyword is followed
1513: by a syntax specific to each constructor.</P>
1514: <P>
1515: The local attribute definitions appear after the name of the element type
1.6 cvs 1516: being defined, if this element type has <A href="#sectc327">local
1.1 cvs 1517: attributes</A>.</P>
1518: <PRE>
1519: Definition = BaseType [ LocAttrSeq ] / Constr / Element .
1520: BaseType = 'TEXT' / 'GRAPHICS' / 'SYMBOL' / 'PICTURE' /
1521: 'UNIT' / 'NATURE' .
1522: Element = ElemID [ ExtOrDef ] .
1523: ExtOrDef = 'EXTERN' / 'INCLUDED' /
1524: [ LocAttrSeq ] '=' Definition .
1525: Constr = 'LIST' [ '[' min '..' max ']' ] 'OF'
1526: '(' DefWithAttr ')' /
1527: 'BEGIN' DefOptSeq 'END' /
1528: 'AGGREGATE' DefOptSeq 'END' /
1529: 'CASE' 'OF' DefSeq 'END' /
1530: 'REFERENCE' '(' RefType ')' /
1531: 'PAIR' .
1532: </PRE>
1533:
1534: <DIV class="subsubsection">
1.6 cvs 1535: <H4><A name=sectd3281>List</A></H4>
1.1 cvs 1536:
1537: <P>
1538: The list constructor permits the definition of an element type composed of a
1539: list of elements, all of the same type. A list definition begins with the
1540: <TT>LIST</TT> keyword followed by an optional range, the keyword <TT>OF</TT>,
1541: and the definition, between parentheses, of the element type which must
1542: compose the list. The optional range is composed of the minimum and maximum
1543: number of elements for the list separated by two periods and enclosed by
1544: brackets. If the range is not present, the number of list elements is
1545: unconstrained. When only one of the two bounds of the range is unconstrained,
1546: it is represented by a star ('*') character. Even when both bounds are
1547: unconstrained, they can be specified by <TT>[*..*]</TT>, but it is simpler not
1548: to specify any bound.</P>
1549: <PRE>
1550: 'LIST' [ '[' min '..' max ']' ]
1551: 'OF' '(' DefWithAttr ')'
1552: min = Integer / '*' .
1553: max = Integer / '*' .
1554: Integer = NUMBER .
1555: </PRE>
1556: <P>
1.2 cvs 1557: Before the document is edited, Thot creates the minimum number of elements for
1558: the list. If no minimum was given, it creates a single element. If a maximum
1559: number of elements is given and that number is attained, the editor refuses to
1560: create new elements for the list.</P>
1.1 cvs 1561: <BLOCKQUOTE class="example">
1562: <P>
1563: <STRONG>Example:</STRONG></P>
1564: <P>
1.3 cvs 1565: The following two instructions define the body of a document as a sequence of
1566: at least two chapters and the contents of a section as a sequence of
1567: paragraphs. A single paragraph can be the entire contents of a section.</P>
1.1 cvs 1568: <PRE>
1569: Body = LIST [2..*] OF (Chapter);
1570: Section_contents = LIST OF (Paragraph);
1571: </PRE>
1572: </BLOCKQUOTE>
1573: </DIV>
1574:
1575: <DIV class="subsubsection">
1.6 cvs 1576: <H4><A name=sectd3282>Aggregate</A></H4>
1.1 cvs 1577:
1578: <P>
1579: The aggregate constructor is used to define an element type as a collection of
1580: sub-elements, each having a fixed type. The collection may be ordered or
1581: unordered. The elements composing the collection are called
1582: <EM>components</EM>. In the definition of an aggregate, a keyword indicates
1583: whether or not the aggregate is ordered: <TT>BEGIN</TT> for an ordered
1584: aggregate, <TT>AGGREGATE</TT> for an unordered aggregate. This keyword is
1585: followed by the list of component type definitions which is terminated by the
1586: <TT>END</TT> keyword. The component type definitions are separated by
1587: commas.</P>
1588: <P>
1589: Before creating an aggregate, the Thot editor creates all the aggregate's
1590: components in the order they appear in the structure schema, even for
1591: unordered aggregates. However, unlike ordered aggregates, the components of
1592: an unordered aggregate may be rearranged using operations of the Thot editor.
1593: The exceptions to the rule are any components whose name was preceded by a
1594: question mark character ('?'). These components, which are optional, can be
1595: created by explicit request, possibly at the time the aggregate is created,
1596: but they are not created automatically <EM>prior</EM> to the creation of the
1597: aggregate.</P>
1598: <PRE>
1599: 'BEGIN' DefOptSeq 'END'
1600: DefOptSeq = DefOpt ';' < DefOpt ';' > .
1601: DefOpt = [ '?' ] DefWithAttr .
1602: </PRE>
1603: <BLOCKQUOTE class="example">
1604: <P>
1605: <STRONG>Example:</STRONG></P>
1606: <P>
1.3 cvs 1607: In a bilingual document, each paragraph has an English version and a French
1608: version. In certain cases, the translator wants to add a marginal note, but
1609: this note is present in very few paragraphs. Thus, it must not be created
1610: systematically for every paragraph. A bilingual paragraph of this type is
1.1 cvs 1611: declared:</P>
1612: <PRE>
1613: Bilingual_paragraph = BEGIN
1614: French_paragraph = TEXT;
1615: English_paragraph = TEXT;
1616: ? Note = TEXT;
1617: END;
1618: </PRE>
1619: </BLOCKQUOTE>
1620: </DIV>
1621:
1622: <DIV class="subsubsection">
1.6 cvs 1623: <H4><A name=sectd3283>Choice</A></H4>
1.1 cvs 1624:
1625: <P>
1626: The choice constructor permits the definition of an element type which is
1627: chosen from among a set of possible types. The keywords <TT>CASE</TT> and
1628: <TT>OF</TT> are followed by a list of definitions of possible types, which are
1629: separated by semicolons and terminated by the <TT>END</TT> keyword.</P>
1630: <PRE>
1631: 'CASE' 'OF' DefSeq 'END'
1632: DefSeq = DefWithAttr ';' < DefWithAttr ';' > .
1633: </PRE>
1634: <P>
1635: Before the creation of an element defined as a choice, the Thot editor
1636: presents the list of possible types for the element to the user. The user has
1.5 cvs 1637: only to select the element type that s/he wants to create from this list.</P>
1.1 cvs 1638: <P>
1639: The order of the type declarations is important. It determines the order of
1640: the list presented to the user before the creation of the element. Also, when
1641: a Choice element is being created automatically, the first type in the list is
1642: used. In fact, using the Thot editor, when an empty Choice element is
1643: selected, it is possible to select this element and to enter its text from
1644: keyboard. In this case, the editor uses the first element type which can
1645: contain an atom of the character string type.</P>
1646: <P>
1647: The two special cases of the choice constructor, the <A
1.6 cvs 1648: href="#sectc328"><EM>schema</EM></A> and the <A
1649: href="#sectc3212"><EM>unit</EM></A> are discussed elsewhere.</P>
1.1 cvs 1650: <BLOCKQUOTE class="example">
1651: <P>
1652: <STRONG>Example:</STRONG></P>
1653: <P>
1.3 cvs 1654: It is common in documents to treat a variety of objects as if they were
1655: ordinary paragraphs. Thus, a ``Paragraph'' might actually be composed of a
1656: block of text (an ordinary paragraph), or a mathematical formula whose
1657: structure is defined by another structure schema named Math, or a table, also
1658: defined by another structure schema. Here is a definition of such a
1.1 cvs 1659: paragraph:</P>
1660: <PRE>
1661: Paragraph = CASE OF
1662: Simple_text = TEXT;
1663: Formula = Math;
1664: Table_para = Table;
1665: END;
1666: </PRE>
1667: </BLOCKQUOTE>
1668: </DIV>
1669:
1670: <DIV class="subsubsection">
1.6 cvs 1671: <H4><A name=sectd3284>Reference</A></H4>
1.1 cvs 1672:
1673: <P>
1674: Like all elements in Thot, references are typed. An element type defined as a
1675: reference is a cross-reference to an element of some other given type. The
1676: keyword <TT>REFERENCE</TT> is followed by the name of a type enclosed in
1677: parentheses. When the type which is being cross-referenced is defined in
1678: another structure schema, the type name is itself followed by the name of the
1679: external structure schema in which it is defined.</P>
1680: <P>
1.6 cvs 1681: When the designated element type is a <A href="#sectd3285">mark pair</A>, it can
1.1 cvs 1682: be preceded by a <TT>FIRST</TT> or <TT>SECOND</TT> keyword. These keywords
1683: indicate whether the reference points to the first or second mark of the pair.
1684: If the reference points to a pair and neither of these two keywords is
1685: present, the reference is considered to point to the first mark of the
1686: pair.</P>
1687: <P>
1688: There is an exception to the principle of typed references: it is possible to
1689: define a reference which designates an element of any type, which can either
1690: be in the same document or another document. In this case, it suffices to put
1691: the keyword <TT>ANY</TT> in the parentheses which indicate the referenced
1692: element type.</P>
1693: <PRE>
1694: 'REFERENCE' '(' RefType ')'
1695: RefType = 'ANY' / [ FirstSec ] ElemID [ ExtStruct ] .
1696: </PRE>
1697: <P>
1698: When defining an inclusion, the <TT>REFERENCE</TT> keyword is not used.
1699: Inclusions with complete expansion are not declared as such in the structure
1700: schemas, since any element defined in a structure schema can be replaced by an
1701: element of the same type. Instead, inclusions without expansion or with
1702: partial expansion must be declared explicitly whenever they will include a
1703: complete object ( and not a part of an object). In this case, the object type
1704: to be included (that is, the name of its structure schema) is followed by a
1705: keyword: <TT>EXTERN</TT> for inclusion without expansion and <TT>INCLUDED</TT>
1706: for partial expansion.</P>
1707: <P>
1708: Before creating a cross-reference or an inclusion, the Thot editor asks the
1709: user to choose, from the document images displayed, the referenced or included
1710: element.</P>
1711: <BLOCKQUOTE class="example">
1712: <P>
1713: <STRONG>Example:</STRONG></P>
1714: <P>
1.3 cvs 1715: If the types Note and Section are defined in the Article structure schema, it
1716: is possible to define, in the same structure schema, a reference to a note and
1717: a reference to a section in this manner:</P>
1.1 cvs 1718: <PRE>
1719: Ref_note = REFERENCE (Note);
1720: Ref_section = REFERENCE (Section);
1721: </PRE>
1722: <P>
1723: It is also possible to define the generic structure of a collection of
1724: articles, which include (with partial expansion) objects of the Article class
1725: and which possess an introduction which may include cross-references to
1726: sections of the included articles. In the Collection structure schema, the
1727: definitions are:</P>
1728: <PRE>
1729: Collection = BEGIN
1.6 cvs 1730: Collection_title = TEXT;
1731: Introduction = LIST OF (Elem = CASE OF
1.1 cvs 1732: TEXT;
1733: Ref_sect;
1734: END);
1.6 cvs 1735: Body = LIST OF (Article INCLUDED);
1736: END;
1737: Ref_sect = REFERENCE (Section (Article));
1.1 cvs 1738: </PRE>
1739: <P>
1740: Here we define a Folder document class which has a title and includes
1741: documents of different types, particularly Folders:</P>
1742: <PRE>
1.6 cvs 1743: Folder = BEGIN
1744: Folder_title = TEXT;
1745: Folder_contents = LIST OF (Document);
1746: END;
1.1 cvs 1747:
1748: Document = CASE OF
1749: Article EXTERN;
1750: Collection EXTERN;
1751: Folder EXTERN;
1752: END;
1753: </PRE>
1754: <P>
1755: Under this definition, Folder represents either an aggregate which contains a
1756: folder title and the list of included documents or an included folder. To
1757: resolve this ambiguity, in the P language, the placement of a star character
1758: in front of the type name (here, Folder) indicates an included document.</P>
1759: </BLOCKQUOTE>
1760: </DIV>
1761:
1762: <DIV class="subsubsection">
1.6 cvs 1763: <H4><A name=sectd3285>Mark pairs</A></H4>
1.1 cvs 1764:
1765: <P>
1766: Like other elements, mark pairs are typed. The two marks of the pair have the
1767: same type, but there exist two predefined subtypes which apply to all mark
1768: pairs: the first mark of the pair (called <TT>First</TT> in the P and T
1769: languages) and the second mark (called <TT>Second</TT>).</P>
1770: <P>
1771: In the S language, a mark pair is noted simply by the <TT>PAIR</TT>
1772: keyword.</P>
1773: <P>
1774: In the Thot editor, marks are always moved or destroyed together. The two
1775: marks of a pair have the same identifier, unique within the document, which
1776: permits intertwining mark pairs without risk of ambiguity.</P>
1777: </DIV>
1778: </DIV>
1779:
1780: <DIV class="subsection">
1.6 cvs 1781: <H3><A name=sectc329>Imports</A></H3>
1.1 cvs 1782:
1783: <P>
1784: Because of schema constructors, it is possible, before editing a document, to
1785: use classes defined by other structure schemas whenever they are needed. It is
1786: also possible to assign specific document classes to certain element types. In
1787: this case, these classes are simply designated by their name. In fact, if a
1788: type name is not defined in the structure schema, it is assumed that it
1789: specifies a structure defined by another structure schema.</P>
1790: <BLOCKQUOTE class="example">
1791: <P>
1792: <STRONG>Example:</STRONG></P>
1793: <P>
1.3 cvs 1794: If the types Math and Table don't appear in the left part of a structure rule
1795: in the schema, the following two rules indicate that a formula has the
1796: structure of an object defined by the structure schema Math and that a table
1797: element has the structure of an object defined by the Table schema.</P>
1.1 cvs 1798: <PRE>
1.6 cvs 1799: Formula = Math;
1.1 cvs 1800: Table_elem = Table;
1801: </PRE>
1802: </BLOCKQUOTE>
1803: </DIV>
1804:
1805: <DIV class="subsection">
1.6 cvs 1806: <H3><A name=sectc3210>Extension rules</A></H3>
1.1 cvs 1807:
1808: <P>
1809: The <TT>EXTENS</TT> section, which can only appear in an extension schema,
1810: defines complements to the rules in the primary schema (i.e. the structure
1811: schema to which the extension schema will be applied). More precisely, this
1812: section permits the addition to an existing type of local attributes,
1813: extensions, restrictions and fixed-value attributes.</P>
1814: <P>
1815: These additions can be applied to the root rule of the primary schema,
1816: designated by the keyword <TT>Root</TT>, or to any other explicitly named
1817: rule.</P>
1818: <P>
1819: Extension rules are separated from each other by a semicolon and each
1.6 cvs 1820: extension rule has the same syntax as a <A href="#sectc327">structure
1.1 cvs 1821: rule</A>, but the part which defines the constructor is absent.</P>
1822: <PRE>
1823: ExtenRuleSeq = ExtensRule ';' < ExtensRule ';' > .
1.6 cvs 1824: ExtensRule = RootOrElem [ LocAttrSeq ]
1825: [ '+' '(' ExtensionSeq ')' ]
1826: [ '-' '(' RestrictSeq ')' ]
1827: [ 'WITH' FixedAttrSeq ] .
1828: RootOrElem = 'Root' / ElemID .
1.1 cvs 1829: </PRE>
1830: </DIV>
1831:
1832: <DIV class="subsection">
1.6 cvs 1833: <H3><A name=sectc3211>Associated elements</A></H3>
1.1 cvs 1834:
1835: <P>
1836: If associated elements are necessary, they must be declared in a specific
1837: section of the structure schema, introduced by the keyword <TT>ASSOC</TT>.
1838: Each associated element type is specified like any other structured element.
1839: However, these types must not appear in any other element types of the schema,
1840: except in <TT>REFERENCE</TT> rules.</P>
1841: </DIV>
1842:
1843: <DIV class="subsection">
1.6 cvs 1844: <H3><A name=sectc3212>Units</A></H3>
1.1 cvs 1845:
1846: <P>
1847: The <TT>UNITS</TT> section of the structure schema contains the declarations
1848: of the element types which can be used in the external objects making up parts
1849: of the document or in objects of the class defined by the schema. As with
1850: associated elements, these element types are defined just like other
1851: structured element types. They can be used in the other element types of the
1852: schema, but they can also be used in any other rule of the schema.</P>
1853: <BLOCKQUOTE class="example">
1854: <P>
1855: <STRONG>Example:</STRONG></P>
1856: <P>
1857: If references to notes are declared as units:</P>
1858: <PRE>
1859: UNITS
1860: Ref_note = REFERENCE (Note);
1861: </PRE>
1862: <P>
1.3 cvs 1863: then it is possible to use references to notes in a cell of a table, even when
1.5 cvs 1864: <TT>Table</TT> is an external structure schema. The <TT>Table</TT> schema must
1.1 cvs 1865: declare a cell to be a sequence of units, which can then be base element types
1.6 cvs 1866: (text, for example) or references to notes in the document.</P>
1867: <PRE>
1.1 cvs 1868: Cell = LIST OF (UNITS);
1869: </PRE>
1870: </BLOCKQUOTE>
1871: </DIV>
1872:
1873: <DIV class="subsection">
1.6 cvs 1874: <H3><A name=sectc3213>Skeleton elements</A></H3>
1.1 cvs 1875:
1876: <P>
1877: When editing a document which contains or must contain external references to
1878: several other documents, it may be necessary to load a large number of
1879: documents, simply to see the parts designated by the external references of
1880: the document while editing, or to access the source of included elements. In
1881: this case, the external documents are not modified and it is only necessary to
1882: see the elements of these documents which could be referenced. Because of
1883: this, the editor will suggest that the documents be loaded in ``skeleton''
1884: form. This form contains only the elements of the document explicitly
1885: mentioned in the <TT>EXPORT</TT> section of their structure schema and, for
1886: these elements, only the part of the contents specified in that section. This
1887: form has the advantage of being very compact, thus requiring very few
1888: resources from the editor. This is also the skeleton form which constitutes
1889: the expanded form of <A href="#inclusion">inclusions</A> with partial
1890: expansion.</P>
1891: <P>
1892: Skeleton elements must be declared explicitly in the <TT>EXPORT</TT> section
1893: of the structure schema that defines them. This section begins with the
1894: keyword <TT>EXPORT</TT> followed by a comma-separated list of the element
1895: types which must appear in the skeleton form and ending with a semicolon.
1896: These types must have been previously declared in the schema.</P>
1897: <P>
1898: For each skeleton element type, the part of the contents which is loaded by
1899: the editor, and therefore displayable, can be specified by putting the keyword
1900: <TT>WITH</TT> and the name of the contained element type to be loaded after
1901: the name of the skeleton element type. In this case only that named element,
1902: among all the elements contained in the exportable element type, will be
1903: loaded. If the <TT>WITH</TT> is absent, the entire contents of the skeleton
1904: element will be loaded by the editor. If instead, it is better that the
1905: skeleton form not load the contents of a particular element type, the keyword
1906: <TT>WITH</TT> must be followed by the word <TT>Nothing</TT>.</P>
1907: <PRE>
1908: [ 'EXPORT' SkeletonSeq ]
1909:
1910: SkeletonSeq = SkelElem < ',' SkelElem > ';' .
1911: SkelElem = ElemID [ 'WITH' Contents ] .
1912: Contents = 'Nothing' / ElemID [ ExtStruct ] .
1913: </PRE>
1914: <BLOCKQUOTE class="example">
1915: <P>
1916: <STRONG>Example:</STRONG></P>
1917: <P>
1.3 cvs 1918: Suppose that, in documents of the article class, the element types
1919: Article_title, Figure, Section, Paragraph, and Biblio should appear in the
1920: skeleton form in order to make it easier to create external references to them
1921: from other documents. When loading an article in its skeleton form, all of
1922: these element types will be loaded except for paragraphs, but only the article
1.5 cvs 1923: title will be loaded in its entirety. For figures, the caption will be loaded,
1.3 cvs 1924: while for sections, the title will be loaded, and for bibliographic entries,
1925: only the title that they contain will be loaded. Note that
1926: bibliographic elements are defined in another structure schema, RefBib. To
1927: produce this result, the following declarations should be placed in the
1928: Article structure schema:</P>
1.1 cvs 1929: <PRE>
1930: EXPORT
1931: Article_title,
1.5 cvs 1932: Figure With Caption,
1.1 cvs 1933: Section With Section_title,
1934: Paragraph With Nothing,
1935: Biblio With Biblio_title(RefBib);
1936: </PRE>
1937: </BLOCKQUOTE>
1938: </DIV>
1939:
1940: <DIV class="subsection">
1.6 cvs 1941: <H3><A name=sectc3214>Exceptions</A></H3>
1.1 cvs 1942:
1943: <P>
1944: The behavior of the Thot editor and the actions that it performs are
1945: determined by the structure schemas. These actions are applied to all
1946: document and object types in accordance with their generic structure. For
1947: certain object types, such as tables and graphics, these actions are not
1948: sufficient or are poorly adapted and some special actions must be added to or
1949: substituted for certain standard actions. These special actions are called
1950: <EM>exceptions</EM>.</P>
1951: <P>
1952: Exceptions only inhibit or modify certain standard actions, but they can be
1953: used freely in every structure schema.</P>
1954: <P>
1955: Each structure schema can contain a section defining exceptions. It begins
1956: with the keyword <TT>EXCEPT</TT> and is composed of a sequence of exception
1957: declarations, separated by semicolons. Each declaration of an exception
1958: begins with the name of an element type or attribute followed by a colon. This
1959: indicates the element type or attribute to which the following exceptions
1.6 cvs 1960: apply. When the given element type name is a <A href="#sectd3285">mark pair</A>,
1.1 cvs 1961: and only in this case, the type name can be preceded by the keyword
1962: <TT>First</TT> or <TT>Second</TT>, to indicate if the exceptions which follow
1963: are associated with the first mark of the pair or the second. In the absence
1964: of this keyword, the first mark is used.</P>
1965: <P>
1.6 cvs 1966: When placed in an <A href="#sectc322">extension schema</A>, the keyword
1.1 cvs 1967: <TT>EXTERN</TT> indicates that the type name which follows is found in the
1968: principal schema (the schema being extended by the extension schema). The
1969: exceptions are indicated by a name. They are separated by semicolons.</P>
1970: <PRE>
1971: [ 'EXCEPT' ExceptSeq ]
1972:
1973: ExceptSeq = Except ';' < Except ';' > .
1974: Except = [ 'EXTERN' ] [ FirstSec ] ExcTypeOrAttr
1975: ':' ExcValSeq .
1976: ExcTypeOrAttr = ElemID / AttrID .
1977: ExcValSeq = ExcValue < ',' ExcValue > .
1978: ExcValue ='NoCut' / 'NoCreate' /
1979: 'NoHMove' / 'NoVMove' / 'NoMove' /
1980: 'NoHResize' / 'NoVResize' / 'NoResize' /
1981: 'NewWidth' / 'NewHeight' /
1982: 'NewHPos' / 'NewVPos' /
1983: 'Invisible' / 'NoSelect' /
1984: 'Hidden' / 'ActiveRef' /
1985: 'ImportLine' / 'ImportParagraph' /
1986: 'NoPaginate' / 'ParagraphBreak' /
1.9 cvs 1987: 'HighlightChildren' / 'ExtendedSelection' /
1988: 'ReturnCreateNL' .
1.1 cvs 1989: </PRE>
1990: <P>
1991: The following are the available exceptions:</P>
1992: <DL>
1993: <DT><TT>NoCut</TT></DT>
1.2 cvs 1994: <DD>This exception can only be applied to element types. Elements of a type to
1995: which this exception is applied cannot be destroyed by the editor.
1.1 cvs 1996: </DD>
1997: <DT><TT>NoCreate</TT></DT>
1.2 cvs 1998: <DD>This exception can only be applied to element types. Elements of a type to
1999: which this exception is applied cannot be created by ordinary commands for
2000: creating new elements. These elements are usually created by special actions
1.1 cvs 2001: associated with otherexceptions.
2002: </DD>
2003: <DT><TT>NoHMove</TT></DT>
1.2 cvs 2004: <DD>This exception can only be applied to element types. Elements of a type to
2005: which this exception is applied cannot be moved horizontally with the mouse.
1.1 cvs 2006: </DD>
2007: <DT><TT>NoVMove</TT></DT>
1.2 cvs 2008: <DD>This exception can only be applied to element types. Elements of a type to
1.5 cvs 2009: which this exception is applied cannot be moved vertically with the mouse.
1.1 cvs 2010: </DD>
2011: <DT><TT>NoMove</TT></DT>
1.2 cvs 2012: <DD>This exception can only be applied to element types. Elements of a type to
2013: which this exception is applied cannot be moved in any direction with the
1.1 cvs 2014: mouse.
2015: </DD>
2016: <DT><TT>NoHResize</TT></DT>
1.2 cvs 2017: <DD>This exception can only be applied to element types. Elements of a type to
2018: which this exception is applied cannot be resized horizontally with the mouse.
1.1 cvs 2019: </DD>
2020: <DT><TT>NoVResize</TT></DT>
1.2 cvs 2021: <DD>This exception can only be applied to element types. Elements of a type to
2022: which this exception is applied cannot be resized vertically with the mouse.
1.1 cvs 2023: </DD>
2024: <DT><TT>NoResize</TT></DT>
1.2 cvs 2025: <DD>This exception can only be applied to element types. Elements of a type to
2026: which this exception is applied cannot be resized in any direction with the
1.1 cvs 2027: mouse.
2028: </DD>
2029: <DT><TT>NoSelect</TT></DT>
1.2 cvs 2030: <DD>This exception can only be applied to element types. Elements of a type to
2031: which this exception is applied cannot be selected directly with the mouse, but
2032: they can be selected by other methods provided by the editor.
1.1 cvs 2033: </DD>
2034: <DT><TT>NewWidth</TT></DT>
1.2 cvs 2035: <DD>This exception can only be applied to numeric attributes. If the width of
2036: an element which has this attribute is modified with the mouse, the value of
2037: the new width will be assigned to the attribute.
1.1 cvs 2038: </DD>
2039: <DT><TT>NewHeight</TT></DT>
1.2 cvs 2040: <DD>This exception can only be applied to numeric attributes. If the height of
2041: an element which has this attribute is modified with the mouse, the value of
2042: the new height will be assigned to the attribute.
1.1 cvs 2043: </DD>
2044: <DT><TT>NewHPos</TT></DT>
1.2 cvs 2045: <DD>This exception can only be applied to numeric attributes. If the
2046: horizontal position of an element which has this attribute is modified with the
2047: mouse, the value of the new horizontal position will be assigned to the
1.1 cvs 2048: attribute.
2049: </DD>
2050: <DT><TT>NewVPos</TT></DT>
1.2 cvs 2051: <DD>This exception can only be applied to numeric attributes. If the vertical
2052: position of an element which has this attribute is modified with the mouse, the
2053: value of the new vertical position will be assigned to the attribute.
1.1 cvs 2054: </DD>
2055: <DT><TT>Invisible</TT></DT>
1.2 cvs 2056: <DD>This exception can only be applied to attributes, but can be applied to all
2057: attribute types. It indicates that the attribute must not be seen by the user
2058: and that its value must not be changed directly. This exception is usually
1.5 cvs 2059: used when another exception manipulates the value of an attribute.
1.1 cvs 2060: </DD>
2061: <DT><TT>Hidden</TT></DT>
1.2 cvs 2062: <DD>This exception can only be applied to element types. It indicates that
2063: elements of this type, although present in the document's structure, must not
2064: be shown to the user of the editor. In particular, the creation menus must not
2065: propose this type and the selection message must not pick it.
1.1 cvs 2066: </DD>
2067: <DT><TT>ActiveRef</TT></DT>
1.2 cvs 2068: <DD>This exception can only be applied to attributes of the reference type. It
2069: indicates that when the user of the editor makes a double click on an element
2070: which possesses a reference attribute having this exception, the element
2071: designated by the reference attribute will be selected.
1.1 cvs 2072: </DD>
2073: <DT><TT>ImportLine</TT></DT>
1.2 cvs 2074: <DD>This exception can only be applied to element types. It indicates that
2075: elements of this type should receive the content of imported text files. An
2076: element is created for each line of the imported file. A structure schema
2077: cannot contain several exceptions <TT>ImportLine</TT> and, if it contains one,
2078: it should not contain any exception <TT>ImportParagraph</TT>.
1.1 cvs 2079: </DD>
2080: <DT><TT>ImportParagraph</TT></DT>
1.2 cvs 2081: <DD>This exception can only be applied to element types. It indicates that
2082: elements of this type should receive the content of imported text files. An
2083: element is created for each paragraph of the imported file. A paragraph is a
2084: sequence of lines without any empty line. A structure schema cannot contain
2085: several exceptions <TT>ImportParagraph</TT> and, if it contains one, it should
2086: not contain any exception <TT>ImportLine</TT>.
1.1 cvs 2087: </DD>
2088: <DT><TT>NoPaginate</TT></DT>
1.2 cvs 2089: <DD>This exception can only be applied to the root element, i.e. the name that
2090: appear after the keyword <TT>STRUCTURE</TT> at the beginning of the structure
2091: schema. It indicates that the editor should not allow the user to paginate
1.1 cvs 2092: documents of that type.
2093: </DD>
2094: <DT><TT>ParagraphBreak</TT></DT>
1.2 cvs 2095: <DD>This exception can only be applied to element types. When the caret is
2096: within an element of a type to which this exception is applied, it is that
2097: element that will be split when the user hits the Return key.
1.1 cvs 2098: </DD>
1.9 cvs 2099: <DT><TT>ReturnCreateNL</TT></DT>
2100: <DD>This exception can only be applied to element types. When the caret is
2101: within an element of a type to which this exception is applied, the Return
2102: key simply inserts a New line character (code \212) at the current position.
2103: The Return key does not create a new element; it does not split the current
2104: element either.
2105: </DD>
1.1 cvs 2106: <DT><TT>HighlightChildren</TT></DT>
1.2 cvs 2107: <DD>This exception can only be applied to element types. Elements of a type to
2108: which this exception is applied are not highlighted themselves when they are
2109: selected, but all their children are highlighted instead.
1.1 cvs 2110: </DD>
2111: <DT><TT>ExtendedSelection</TT></DT>
1.2 cvs 2112: <DD>This exception can only be applied to element types. The selection
2113: extension command (middle button of the mouse) only add the clicked element (if
2114: it has that exception) to the current selection, without selecting other
2115: elements between the current selection and the clicked element.
1.1 cvs 2116: </DD>
2117: </DL>
2118: <BLOCKQUOTE class="example">
2119: <P>
2120: <STRONG>Example:</STRONG></P>
2121: <P>
1.3 cvs 2122: Consider a structure schema for object-style graphics which defines the
1.1 cvs 2123: Graphic_object element type with the associated Height and Weight
1.3 cvs 2124: numeric attributes. Suppose that we want documents of this class to have
2125: the following qualities:</P>
1.1 cvs 2126: <UL>
1.2 cvs 2127: <LI>Whenever the width or height of an object is changed using the mouse, the
2128: new values are stored in the object's Width and Height attributes.
2129: <LI>The user should not be able to change the values of the Width and Height
1.5 cvs 2130: attributes via the Attributes menu of the Thot editor.
1.1 cvs 2131: </UL>
2132: <P>
2133: The following exceptions will produce this effect.</P>
2134: <PRE>
2135: STRUCT
2136: ...
1.5 cvs 2137: Graphics_object (ATTR Height = Integer; Width = Integer)
1.1 cvs 2138: = GRAPHICS with Height ?= 10, Width ?= 10;
2139: ...
2140: EXCEPT
2141: Height: NewHeight, Invisible;
2142: Width: NewWidth, Invisible;
2143: </PRE>
2144: </BLOCKQUOTE>
2145: </DIV>
2146: </DIV>
2147:
2148: <DIV class="section">
1.6 cvs 2149: <H2><A name=sectb33>Some examples</A></H2>
1.1 cvs 2150:
2151: <P>
2152: In order to illustrate the principles of the document model and the syntax of
2153: the S language, this section presents two examples of structure schemas. One
2154: defines a class of documents, the other defines a class of objects.</P>
2155:
2156: <DIV class="subsection">
1.6 cvs 2157: <H3><A name=sectc331>A class of documents: articles</A></H3>
1.1 cvs 2158:
2159: <P>
2160: This example shows a possible structure for articles published in a journal.
2161: Text between braces is comments.</P>
2162: <PRE>
2163: STRUCTURE Article; { This schema defines the Article class }
2164: DEFPRES ArticleP; { The default presentation schema is
2165: ArticleP }
2166: ATTR { Global attribute definitions }
2167: WordType = Definition, IndexWord, DocumentTitle;
2168: { A single global attribute is defined, with three values }
2169: STRUCT { Definition of the generic structure }
2170: Article = BEGIN { The Article class has an aggregate
2171: structure }
2172: Title = BEGIN { The title is an aggregate }
2173: French_title =
2174: Text WITH Language='Fran\347ais';
2175: English_title =
2176: Text WITH Language='English';
2177: END;
2178: Authors =
2179: LIST OF (Author
2180: (ATTR Author_type=principal,secondary)
2181: { The Author type has a local attribute }
2182: = BEGIN
2183: Author_name = Text;
2184: Info = Paragraphs ;
2185: { Paragraphs is defined later }
2186: Address = Text;
2187: END
2188: );
2189: Keywords = Text;
2190: { The journal's editor introduces the article
2191: with a short introduction, in French and
2192: in English }
2193: Introduction =
2194: BEGIN
2195: French_intr = Paragraphs WITH
2196: Language='Fran\347ais';
2197: English_intr = Paragraphs WITH
2198: Language='English';
2199: END;
2200: Body = Sections; { Sections are defined later }
2201: { Appendixes are only created on demand }
2202: ? Appendices =
2203: LIST OF (Appendix =
2204: BEGIN
2205: Appendix_Title = Text;
2206: Appendix_Contents = Paragraphs;
2207: END
2208: );
2209: END; { End of the Article aggregate }
2210:
2211: Sections = LIST [2..*] OF (
2212: Section = { At least 2 sections }
2213: BEGIN
2214: Section_title = Text;
2215: Section_contents =
2216: BEGIN
2217: Paragraphs;
2218: Sections; { Sections at a lower level }
2219: END;
2220: END
2221: );
2222:
2223: Paragraphs = LIST OF (Paragraph = CASE OF
2224: Enumeration =
2225: LIST [2..*] OF
2226: (Item = Paragraphs);
2227: Isolated_formula = Formula;
2228: LIST OF (UNIT);
2229: END
2230: );
2231:
2232: ASSOC { Associated elements definitions }
2233:
2234: Figure = BEGIN
1.5 cvs 2235: Figure_caption = Text;
1.1 cvs 2236: Illustration = NATURE;
2237: END;
2238:
2239: Biblio_citation = CASE OF
2240: Ref_Article =
2241: BEGIN
2242: Authors_Bib = Text;
2243: Article_Title = Text;
2244: Journal = Text;
2245: Page_Numbers = Text;
2246: Date = Text;
2247: END;
2248: Ref_Livre =
2249: BEGIN
2250: Authors_Bib; { Defined above }
2251: Book_Title = Text;
2252: Editor = Text;
2253: Date; { Defined above }
2254: END;
2255: END;
2256:
2257: Note = Paragraphs - (Ref_note);
2258:
2259: UNITS { Elements which can be used in objects }
2260:
2261: Ref_note = REFERENCE (Note);
2262: Ref_biblio = REFERENCE (Biblio_citation);
2263: Ref_figure = REFERENCE (Figure);
2264: Ref_formula = REFERENCE (Isolated_formula);
2265:
2266: EXPORT { Skeleton elements }
2267:
2268: Title,
1.5 cvs 2269: Figure with Figure_caption,
1.1 cvs 2270: Section With Section_title;
2271:
2272: END { End of the structure schema }
2273: </PRE>
2274: <P>
2275: This schema is very complete since it defines both paragraphs and
2276: bibliographic citations. These element types could just as well be defined in
2277: other structure schemas, as is the case with the <TT>Formula</TT> class. All
2278: sorts of other elements can be inserted into an article, since a paragraph can
2279: contain any type of unit. Similarly, figures can be any class of document or
2280: object that the user chooses.</P>
2281: <P>
2282: Generally, an article doesn't contain appendices, but it is possible to add
2283: them on explicit request: this is the effect of the question mark before the
2284: word Appendices.</P>
2285: <P>
2286: The Figure, Biblio_citation and Note elements are associated elements. Thus,
2287: they are only used in <TT>REFERENCE</TT> statements.</P>
2288: <P>
2289: Various types of cross-references can be put in paragraphs. They can also be
2290: placed the objects which are part of the article, since the cross-references
2291: are defined as units (<TT>UNITS</TT>).</P>
2292: <P>
2293: There is a single restriction to prevent the creation of Ref_note elements
2294: within notes.</P>
2295: <P>
2296: It is worth noting that the S language permits the definition of recursive
2297: structures like sections: a section can contain other sections (which are thus
2298: at the next lower level of the document tree). Paragraphs are also recursive
2299: elements, since a paragraph can contain an enumeration in which each element
2300: (<TT>Item</TT>) is composed of paragraphs.</P>
2301: </DIV>
2302:
2303: <DIV class="subsection">
1.6 cvs 2304: <H3><A name=sectc332>A class of objects: mathematical formulas</A></H3>
1.1 cvs 2305:
2306: <P>
2307: The example below defines the <TT>Formula</TT> class which is used in Article
2308: documents. This class represents mathematical formulas with a rather simple
2309: structure, but sufficient to produce a correct rendition on the screen or
2310: printer. To support more elaborate operations (formal or numeric
2311: calculations), a finer structure should be defined. This class doesn't use any
2312: other class and doesn't define any associated elements or units.</P>
2313: <PRE>
2314: STRUCTURE Formula;
2315: DEFPRES FormulaP;
2316:
2317: ATTR
2318: String_type = Function_name, Variable_name;
2319:
2320: STRUCT
2321: Formula = Expression;
2322: Expression = LIST OF (Construction);
2323: Construction = CASE OF
2324: TEXT; { Simple character string }
2325: Index = Expression;
2326: Exponent = Expression;
2327: Fraction =
2328: BEGIN
1.6 cvs 2329: Numerator = Expression;
1.1 cvs 2330: Denominator = Expression;
2331: END;
2332: Root =
2333: BEGIN
2334: ? Order = TEXT;
2335: Root_Contents = Expression;
2336: END;
2337: Integral =
2338: BEGIN
2339: Integration_Symbol = SYMBOL;
2340: Lower_Bound = Expression;
2341: Upper_Bound = Expression;
2342: END;
2343: Triple =
2344: BEGIN
2345: Princ_Expression = Expression;
2346: Lower_Expression = Expression;
2347: Upper_Expression = Expression;
2348: END;
2349: Column = LIST [2..*] OF
2350: (Element = Expression);
2351: Parentheses_Block =
2352: BEGIN
2353: Opening = SYMBOL;
2354: Contents = Expression;
2355: Closing = SYMBOL;
2356: END;
2357: END; { End of Choice Constructor }
2358: END { End of Structure Schema }
2359: </PRE>
2360: <P>
2361: This schema defines a single global attribute which allows functions and
2362: variables to be distinguished. In the presentation schema, this attribute can
2363: be used to choose between roman (for functions) and italic characters (for
2364: variables).</P>
2365: <P>
2366: A formula's structure is that of a mathematical expression, which is itself a
2367: sequence of mathematical constructions. A mathematical construction can be
2368: either a simple character string, an index, an exponent, a fraction, a root,
2369: etc. Each of these mathematical constructions has a sensible structure which
2370: generally includes one or more expressions, thus making the formula class's
2371: structure definition recursive.</P>
2372: <P>
2373: In most cases, the roots which appear in the formulas are square roots and
2374: their order (2) is not specified. This is why the Order component is marked
2375: optional by a question mark. When explicitly requested, it is possible to add
2376: an order to a root, for example for cube roots (order = 3).</P>
2377: <P>
2378: An integral is formed by an integration symbol, chosen by the user (simple
2379: integral, double, curvilinear, etc.), and two bounds. A more fine-grained
2380: schema would add components for the integrand and the integration variable.
2381: Similarly, the Block_Parentheses construction leaves the choice of opening and
2382: closing symbols to the user. They can be brackets, braces, parentheses,
2383: etc.</P>
2384: </DIV>
2385: </DIV>
2386: <HR>
2387: </DIV>
2388:
2389: <DIV class="chapter">
1.6 cvs 2390: <H1><A name=sect4>The P Language</A></H1>
1.1 cvs 2391:
2392:
2393: <DIV class="section">
1.6 cvs 2394: <H2><A name=sectb41>Document presentation</A></H2>
1.1 cvs 2395:
2396: <P>
2397: Because of the model adopted for Thot, the presentation of documents is
2398: clearly separated from their structure and content. After having presented
2399: the logical structure of documents, we now detail the principles implemented
2400: for their presentation. The concept of <EM>presentation</EM> encompasses what
1.5 cvs 2401: is often called the page layout, the composition, or the document style. It
2402: is the set of operations which display the document on the screen or print
2403: it on paper. Like logical structure, document presentation is defined
2404: generically with the help of a language, called P.</P>
1.1 cvs 2405:
2406: <DIV class="subsection">
1.6 cvs 2407: <H3><A name=sectc411>Two levels of presentation</A></H3>
1.1 cvs 2408:
2409: <P>
2410: The link between structure and presentation is clear: the logical organization
2411: of a document is used to carry out its presentation, since the purpose of the
2412: presentation is to make evident the organization of the document. But the
2413: presentation is equally dependent on the device used to render the document.
2414: Certain presentation effects, notably changes of font or character set, cannot
2415: be performed on all printers or on all screens. This is why Thot uses a
2416: two-level approach, where the presentation is first described in abstract
2417: terms, without taking into account each particular device, and then the
2418: presentation is realized within the constraints of a given device.</P>
2419: <P>
2420: Thus, presentation is only described as a function of the structure of the
2421: documents and the image that would be produced on an idealized device. For
2422: this reason, presentation descriptions do not refer to any device
2423: characteristics: they describe <EM>abstract presentations</EM> which can be
2424: concretized on different devices.</P>
2425: <P>
2426: A presentation description also defines a <EM>generic presentation</EM>, since
2427: it describes the appearance of a class of documents or objects. This generic
2428: presentation must also be applied to document and object instances, each
2429: conforming to its generic logical structure, but with all the allowances that
2430: were called to mind above: missing elements, constructed elements with other
2431: logical structures, etc.</P>
2432: <P>
2433: In order to preserve the homogeneity between documents and objects,
2434: presentation is described with a single set of tools which support the layout
2435: of a large document as well as the composition of objects like a graphical
2436: figure or mathematical formula. This unity of presentation description tools
2437: contrasts with the traditional approach, which focuses more on documents than
2438: objects and thus is based on the usual typographic conventions, such as the
2439: placement of margins, indentations, vertical spaces, line lengths,
2440: justification, font changes, etc.</P>
2441: </DIV>
2442:
2443: <DIV class="subsection">
1.6 cvs 2444: <H3><A name=sectc412>Boxes</A></H3>
1.1 cvs 2445:
2446: <P>
2447: To assure the homogeneity of tools, all presentation in Thot, for documents as
2448: well as for the objects which they contain, is based on the notion of the
2449: <EM>box</EM>, such as was implemented in T<SUB><BIG>E</BIG></SUB>X.</P>
2450: <P>
2451: Corresponding to each element of the document is a box, which is the
2452: rectangle enclosing the element on the display device (screen or sheet of
2453: paper); the outline of this rectangle is normally not visible. The sides of
2454: the box are parallel to the sides of the screen or the sheet of paper. By way
2455: of example, a box is associated with a character string, a line of text, a
2456: page, a paragraph, a title, a mathematical formula, or a table cell.</P>
2457: <P>
2458: Whatever element it corresponds to, each box possesses four sides and four
2459: axes, which we designate as follows (<A href="#boxes">see figure</A>):</P>
2460: <DL>
2461: <DT><TT> Top</TT></DT>
2462: <DD>the upper side,
2463: </DD>
2464: <DT><TT> Bottom</TT></DT>
2465: <DD>the lower side,
2466: </DD>
2467: <DT><TT> Left</TT></DT>
2468: <DD>the left side,
2469: </DD>
2470: <DT><TT> Right</TT></DT>
2471: <DD>the right side,
2472: </DD>
2473: <DT><TT> VMiddle</TT></DT>
1.2 cvs 2474: <DD>the vertical axis passing through the center of the box,
1.1 cvs 2475: </DD>
2476: <DT><TT> HMiddle</TT></DT>
1.2 cvs 2477: <DD>the horizontal axis passing through the center of the box,
1.1 cvs 2478: </DD>
2479: <DT><TT> VRef</TT></DT>
2480: <DD>the vertical reference axis,
2481: </DD>
2482: <DT><TT> HRef</TT></DT>
2483: <DD>the horizontal reference axis.
2484: </DD>
2485: </DL>
2486:
2487: <DIV class="figure">
2488: <HR>
2489: <PRE>
2490: Left VRef VMiddle Right
2491: : :
2492: Top -----------------------------
2493: | : : |
2494: | : : |
2495: | : : |
2496: | : : |
2497: | : : |
2498: HMiddle ..|...........................|..
2499: | : : |
2500: | : : |
2501: HRef ..|...........................|..
2502: | : : |
2503: | : : |
2504: Bottom -----------------------------
2505: : :
2506: </PRE>
2507: <P align=center>
2508: <EM><A name="boxes">The sides and axes of boxes</A><EM></EM></EM></P>
2509: <HR>
2510: </DIV>
2511: <P>
2512: The principal role of boxes is to set the extent and position of the images of
2513: the different elements of a document with respect to each other on the
2514: reproduction device. This is done by defining relations between the boxes of
2515: different elements which give relative extents and positions to these
2516: boxes.</P>
2517: <P>
2518: There are three types of boxes:</P>
2519: <UL>
2520: <LI>boxes corresponding to structural elements of the document,
2521: <LI>presentation boxes,
2522: <LI>page layout boxes.
2523: </UL>
2524: <P>
2525: <STRONG>Boxes corresponding to structural elements of the document</STRONG>
2526: are those which linked to each of the elements (base or structured) of the
2527: logical structure of the document. Such a box contains all the contents of
1.5 cvs 2528: the element to which it corresponds (there is an exception: see
1.6 cvs 2529: <A href="#sectc4220">rules <TT>VertOverflow</TT> and
1.5 cvs 2530: <TT>HorizOverflow</TT></A>). These boxes form a
1.1 cvs 2531: tree-like structure, identical to that of the structural elements to which
2532: they correspond. This tree expresses the inclusion relationships between the
2533: boxes: a box includes all the boxes of its subtree. On the other hand, there
2534: are no predefined rules for the relative positions of the included boxes. If
2535: they are at the same level, they can overlap, be contiguous, or be disjoint.
2536: The rules expressed in the generic presentation specify their relative
2537: positions.</P>
2538: <P>
2539: <STRONG>Presentation boxes</STRONG> represent elements which are not found in
2540: the logical structure of the document but which are added to meet the needs of
2541: presentation. These boxes are linked to the elements of the logical structure
2542: that are best suited to bringing them out. For example, they are used to add
2543: the character string ``Summary:'' before the summary in the presentation of a
2544: report or to represent the fraction bar in a formula, or also to make the
2545: title of a field in a form appear. These elements have no role in the logical
2546: structure of the document: the presence of a Summary element in the document
2547: does not require the creation of another structural object to hold the word
2548: ``Summary''. Similarly, if a Fraction element contains both a Numerator
2549: element and a Denominator element, the fraction bar has no purpose
2550: structurally. On the other hand, these elements of the presentation are
2551: important for the reader of the reproduced document or for the user of an
2552: editor. This is why they must appear in the document's image. It is the
2553: generic presentation which specifies the presentation boxes to add by
2554: indicating their content (a base element for which the value is specified) and
2555: the position that they must take in the tree of boxes. During editing, these
2556: boxes cannot be modified by the user.</P>
2557: <P>
2558: <STRONG>Page layout boxes</STRONG> are boxes created implicitly by the page
2559: layout rules. These rules indicate how the contents of a structured element
2560: must be broken into lines and pages. In contrast to presentation boxes, these
2561: line and page boxes do not depend on the logical structure of the document,
1.5 cvs 2562: but rather on the physical constraints of the output devices: character
1.1 cvs 2563: size, height and width of the window on the screen or of the sheet of
2564: paper.</P>
2565: </DIV>
2566:
2567: <DIV class="subsection">
1.6 cvs 2568: <H3><A name=sectc413>Views and visibility</A></H3>
1.1 cvs 2569:
2570: <P>
2571: One of the operations that one might wish to perform on a document is to view
2572: it is different ways. For this reason, it is possible to define several
2573: <EM>views</EM> for the same document, or better yet, for all documents of the
2574: same class. A view is not a different presentation of the document, but
2575: rather a filter which only allows the display of certain parts of the
2576: document. For example, it might be desirable to see only the titles of
2577: chapters and sections in order to be able to move rapidly through the
2578: document. Such a view could be called a ``table of contents''. It might also
2579: be desirable to see only the mathematical formulas of a document in order to
2580: avoid being distracted by the non-mathematical aspects of the document. A
2581: ``mathematics'' view could provide this service.</P>
2582: <P>
2583: Views, like presentation, are based on the generic logical structure. Each
2584: document class, and each generic presentation, can be provided with views
2585: which are particularly useful for that class or presentation. For each view,
2586: the <EM>visibility</EM> of elements is defined, indicated whether or not the
2587: elements must be presented to the user. The visibility is calculated as a
2588: function of the type of the elements or their hierarchical position in the
2589: structure of the document. Thus, for a table of contents, all the ``Chapter
2590: Title'' and ``Section Title'' elements are made visible. However, the
2591: hierarchical level could be used to make the section titles invisible below a
2592: certain threshold level. By varying this threshold, the granularity of the
2593: view can be varied. In the ``mathematics'' view, only Formula elements would
2594: be made visible, no matter what their hierarchical level.</P>
2595: <P>
2596: Because views are especially useful for producing a synthetic image of the
2597: document, it is necessary to adapt the presentation of the elements to the
2598: view in which they appear. For example, it is inappropriate to have a page
2599: break before every chapter title in the table of contents. Thus, generic
2600: presentations take into account the possible views and permit each element
2601: type's presentation to vary according the view in which its image appears.</P>
2602: <P>
2603: <A name="views">Views</A> are also used, when editing documents, to display
2604: the associated elements. So, in addition to the primary view of the document,
2605: there can be a ``notes'' view and a ``figures'' view which contain,
2606: respectively, the associated elements of the Note and Figure types. In this
2607: way, it is possible to see simultaneously the text which refers to these
2608: elements and the elements themselves, even if they will be separated when
2609: printed.</P>
2610: </DIV>
2611:
2612: <DIV class="subsection">
1.6 cvs 2613: <H3><A name=sectc414>Pages</A></H3>
1.1 cvs 2614:
2615: <P>
2616: Presentation schemas can be defined which display the document as a long
2617: scroll, without page breaks. This type of schema is particularly well-suited
2618: to the initial phase of work on a document, where jumps from page to page
2619: would hinder composing and reading the document on a screen. In this case,
2620: the associated elements (such as notes), which are normally displayed in the
2621: page footer, are presented in a separate window. But, once the document is
2622: written, it may be desirable to display the document on the screen in the same
2623: manner in which it will be printed. So, the presentation schema must define
2624: pages.</P>
2625: <P>
2626: The P language permits the specification of the dimensions of pages as well as
2627: their composition. It is possible to generate running titles, page numbers,
2628: zones at the bottom of the page for notes, etc. The editor follows this model
2629: and inserts page break marks in the document which are used during printing,
2630: insuring that the pages on paper are the same as on the screen.</P>
2631: <P>
2632: Once a document has been edited with a presentation schema defining pages, it
2633: contains page marks. But it is always possible to edit the document using a
2634: schema without pages. In this case, the page marks are simply ignored by the
2635: editor. They are considered again as soon as a schema with pages is used.
2636: Thus, the user is free to choose between schemas with and without pages.</P>
2637: <P>
2638: Thot treats the page break, rather than the page itself, as a box. This page
2639: break box contains all the elements of one page's footer, a rule marking the
2640: edge of this page, and all the elements of the next page's header. The
2641: elements of the header and footer can be running titles, page number,
2642: associated elements (notes, for example), etc. All these elements, as well as
2643: their content and graphical appearance, are defined by the generic
2644: presentation.</P>
2645: </DIV>
2646:
2647: <DIV class="subsection">
1.6 cvs 2648: <H3><A name=sectc415>Numbering</A></H3>
1.1 cvs 2649:
2650: <P>
2651: Many elements are numbered in documents: pages, chapters, sections, formulas,
2652: theorems, notes, figures, bibliographic references, exercises, examples,
2653: lemmas, etc. Because Thot has a notion of logical structure, all of these
2654: numbers (with the exception of pages) are redundant with information implicit
2655: in the logical structure of the document. Such numbers are simply a way to
2656: make the structure of the document more visible. So, they are part of the
2657: document's presentation and are calculated by the editor from the logical
2658: structure. The structure does not contain numbers as such; it only defines
2659: relative structural positions between elements, which serve as ordering
2660: relations on these elements.</P>
2661: <P>
2662: If the structure schema defines the body of a document as a sequence of at
2663: least two chapters:</P>
2664: <PRE>
1.6 cvs 2665: Body = LIST [2..*] OF Chapter;
1.1 cvs 2666: </PRE>
2667: <P>
1.5 cvs 2668: the sequence defined by the list constructor is ordered and each chapter can be
2669: assigned a number based on its rank in the Body list. Therefore, all elements
2670: contained in lists a the structure of a document can be numbered, but they are
2671: not the only ones. The tree structure induced by the aggregate, list, and
2672: choice constructors (excluding references) defines a total order on the
2673: elements of the document's primary structure. So, it is possible to define
2674: a numbering which uses this order, filtering elements according to their type
2675: so that only certain element types are taken into account in the numbering. In
2676: this way, it possible to number all the theorems and lemmas of a chapter in the
2677: same sequence of numbers, even when they are not part of the same list
2678: constructor and appear at different levels of the document's tree. By changing
2679: the filter, they can be numbered separately: one sequence of numbers for
2680: theorems, another for the lemmas.</P>
1.1 cvs 2681: <P>
2682: Associated elements pose a special problem, since they are not part of the
2683: document's primary structure, but are attached only by references, which
2684: violate the total order of the document. Then, these associated elements are
2685: frequently numbered, precisely because the number is an effective way to
2686: visualize the reference. In order to resolve this problem, Thot implicitly
2687: defines a list constructor for each type of associated element, gathering
2688: together (and ordering) these elements. Thus, the associated elements can be
2689: numbered by type.</P>
2690: <P>
2691: Since they are calculated from the document's logical structure and only for
2692: the needs of the presentation, numbers are presentation elements, described by
2693: presentation boxes, just like the fraction bar or the word ``Summary''.
2694: Nevertheless, numbers differ from these other boxes because their content
2695: varies from instance to instance, even though they are of the same type,
2696: whereas all fraction bars are horizontal lines and the same word ``Summary''
2697: appears at the head of every document's summary.</P>
2698: </DIV>
2699:
2700: <DIV class="subsection">
1.6 cvs 2701: <H3><A name=sectc416>Presentation parameters</A></H3>
1.1 cvs 2702:
2703: <P>
2704: The principal parameters which determine document presentation are the
2705: <EM>positions</EM> and <EM>dimensions</EM> of boxes, the <EM>font</EM>, the
2706: <EM>style</EM>, the <EM>size</EM>, the <EM>underlining</EM> and the
2707: <EM>color</EM> of their content. From these parameters, and some others of
2708: less importance, it is possible to represent the usual typographic parameters
2709: for the textual parts of the document. These same parameters can be used to
2710: describe the geometry of the non-textual elements, even though they are
2711: two-dimensional elements unlike the text, which is linear.</P>
2712: <P>
2713: As we have already seen, the positions of the boxes always respect the rule
2714: of enclosure: a box in the tree encloses all the boxes of the next lower level
2715: which are attached to it. The positional parameters permit the specification
2716: of the position of each box in relation to the enclosing box or to its sibling
2717: boxes (boxes directly attached to the same enclosing box in the tree of
2718: boxes).</P>
2719: <P>
2720: The presentation parameters also provide control over the dimensions of the
2721: boxes. The dimensions of a box can depend either on its content or on its
2722: context (its sibling boxes and the enclosing box). Each dimension (height or
2723: width) can be defined independently of the other.</P>
2724: <P>
2725: Because of the position and dimension parameters, it is possible to do the
2726: same things that are normally done in typography by changing margins, line
2727: lengths, and vertical or horizontal skips. This approach can also align or
2728: center elements and groups of elements.</P>
2729: <P>
2730: In contrast to the position and dimension parameters, the font, style, size,
2731: underlining, and color do not concern the box itself (the rectangle delimiting
2732: the element), but its content. These parameters indicate the typographic
2733: attributes which must be applied to the text contained in the box, and by
2734: extension, to all base elements.</P>
2735: <P>
2736: For text, the font parameter is used to change the family of characters
2737: (Times, Helvetica, Courier, etc.); the style is used to obtain italic or
2738: roman, bold or light characters; the size determines the point size of the
2739: characters; underlining defines the type and thickness of the lines drawn
2740: above, below, or through the characters.</P>
2741: <P>
2742: For graphics, the line style parameter can be either solid, dotted, or dashed;
2743: the line thickness parameter controls the width of the lines; the fill pattern
2744: parameter determines how closed geometric figures must be filled.</P>
2745: <P>
2746: While some of the parameters which determine the appearance of a box's
2747: contents make sense only for one content type (text or graphic), other
2748: parameters apply to all content types: these are the color parameters. These
2749: indicate the color of lines and the background color.</P>
2750: </DIV>
2751: </DIV>
2752:
2753: <DIV class="section">
1.6 cvs 2754: <H2><A name=sectb42>Presentation description language</A></H2>
1.1 cvs 2755:
2756: <P>
2757: A generic presentation defines the values of presentation parameters (or the
2758: way to calculate those values) for a generic structure, or more precisely, for
2759: all the element types and all the global and local attributes defined in that
2760: generic structure. This definition of the presentation parameters is made
2761: with the P language. A program written in this language, that is a generic
2762: presentation expressed in P, is call a <EM>presentation schema</EM>. This
2763: section describes the syntax and semantics of the language, using the same <A
1.6 cvs 2764: href="#sectc321">meta-language</A> as was used for the definition of the S
1.1 cvs 2765: language.</P>
2766: <P>
2767: Recall that it is possible to write many different presentation schemas for
2768: the same class of documents or objects. This allows users to choose for a
2769: document the graphical appearance which best suits their type of work or
2770: their personal taste.</P>
2771:
2772: <DIV class="subsection">
1.6 cvs 2773: <H3><A name=sectc421>The organization of a presentation schema</A></H3>
1.1 cvs 2774:
2775: <P>
2776: A presentation schema begins with the word <TT>PRESENTATION</TT> and ends with
2777: the word <TT>END</TT>. The word <TT>PRESENTATION</TT> is followed by the name
2778: of the generic structure to which the presentation will be applied. This name
2779: must be the same as that which follows the keyword <TT>STRUCTURE</TT> in the
2780: structure schema associated with the presentation schema.</P>
2781: <P>
2782: After this declaration of the name of the structure, the following sections
2783: appear (in order):</P>
2784: <UL>
2785: <LI>Declarations of
2786: <UL>
2787: <LI>all views,
2788: <LI>printed views,
2789: <LI>counters,
2790: <LI>presentation constants,
2791: <LI>variables,
2792: </UL>
2793: <LI>default presentation rules,
2794: <LI>presentation box and page layout box definitions,
2795: <LI>presentation rules for structured elements,
2796: <LI>presentation rules for attributes,
2797: <LI>rules for transmitting values to attributes of included documents.
2798: </UL>
2799: <P>
2800: Each of these sections is introduced by a keyword which is followed by a
2801: sequence of declarations. Every section is optional.</P>
2802: <PRE>
2803: SchemaPres ='PRESENTATION' ElemID ';'
2804: [ 'VIEWS' ViewSeq ]
2805: [ 'PRINT' PrintViewSeq ]
2806: [ 'COUNTERS' CounterSeq ]
2807: [ 'CONST' ConstSeq ]
2808: [ 'VAR' VarSeq ]
2809: [ 'DEFAULT' ViewRuleSeq ]
2810: [ 'BOXES' BoxSeq ]
2811: [ 'RULES' PresentSeq ]
2812: [ 'ATTRIBUTES' PresAttrSeq ]
2813: [ 'TRANSMIT' TransmitSeq ]
2814: 'END' .
1.6 cvs 2815: ElemID = NAME .
1.1 cvs 2816: </PRE>
2817: </DIV>
2818:
2819: <DIV class="subsection">
1.6 cvs 2820: <H3><A name=sectc422>Views</A></H3>
1.1 cvs 2821:
2822: <P>
2823: Each of the possible views must be declared in the presentation schema. As
2824: has <A href="#views">already been described</A>, the presentation rules for an
2825: element type can vary according to the view in which the element appears. The
2826: name of the view is used to designate the view to which the presentation rules
2827: apply (see the <A href="#inkeyword"><TT>IN</TT> instruction</A>). The
2828: definition of the view's contents are dispersed throughout the presentation
2829: rules attached to the different element types and attributes. The
2830: <TT>VIEWS</TT> section is simply a sequence of view names separated by commas
2831: and terminated by a semi-colon.</P>
2832: <P>
2833: One of the view names (and only one) can be followed by the keyword
2834: <TT>EXPORT</TT>. This keyword identifies the view which presents the members
1.6 cvs 2835: of the document class in <A href="#sectc3213">skeleton form</A>. The graphical
1.1 cvs 2836: appearance and the content of this view is defined just as with other views,
2837: but it is useless to specify presentation rules concerning this view for the
2838: elements which are not loaded in the skeleton form.</P>
2839: <P>
2840: It is not necessary to declare any views; in this case there is a single
2841: unnamed view. If many views are declared, the first view listed is considered
2842: the principal view. The principal view is the one to which all rules that are
2843: not preceded by an indication of a view will apply (see the <A
2844: href="#inkeyword">instruction <TT>IN</TT></A>).</P>
2845: <P>
2846: The principal view is the the one which the editor presents on the screen when
2847: the user asks to create or edit a document. Thus, it makes sense to put the
2848: most frequently used view at the head of the list. But if the structure
1.6 cvs 2849: schema contains <A href="#sectc3213">skeleton elements</A> and is loaded in its
1.1 cvs 2850: skeleton form, the view whose name is followed by the keyword <TT>EXPORT</TT>
2851: will be opened and no other views can be opened.</P>
2852: <PRE>
1.6 cvs 2853: 'VIEWS' ViewSeq
1.1 cvs 2854: ViewSeq = ViewDeclaration
1.6 cvs 2855: < ',' ViewDeclaration > ';' .
1.1 cvs 2856: ViewDeclaration = ViewID [ 'EXPORT' ] .
2857: ViewID = NAME .
2858: </PRE>
2859: <BLOCKQUOTE class="example">
2860: <P>
2861: <STRONG>Example:</STRONG></P>
2862: <P>
1.3 cvs 2863: When editing a report, it might be useful have views of the table of contents
2864: and of the mathematical formulas, in addition to the principal view which shows
2865: the document in its entirety. To achieve this, a presentation schema for the
2866: Report class would have the following <TT>VIEWS</TT> section:</P>
1.1 cvs 2867: <PRE>
2868: VIEWS
2869: Full_text, Table_of_contents, Formulas;
2870: </PRE>
2871: <P>
2872: The contents of these views are specified in the presentation rules of the
2873: schema.</P>
2874: </BLOCKQUOTE>
2875: </DIV>
2876:
2877: <DIV class="subsection">
1.6 cvs 2878: <H3><A name=sectc423>Print Views</A></H3>
1.1 cvs 2879:
2880: <P>
2881: When editing a document, each view is presented in a different window. In
2882: addition to the views specified by the <TT>VIEWS</TT> instruction, the user
2883: can display the associated elements with one window for each type of
2884: associated element.</P>
2885: <P>
2886: When printing a document, it is possible to print any number of views, chosen
2887: from among all the views which the editor can display (views in the strict
2888: sense or associated elements). Print views, as well as the order in which
2889: they must be printed, are indicated by the <TT>PRINT</TT> instruction. It
2890: appears after the <TT>VIEWS</TT> instruction and is formed of the keyword
2891: <TT>PRINT</TT> followed by the ordered list of print view names. The print
2892: view names are separated by commas and followed by a semi-colon. A print view
2893: name is either a view name declared in the <TT>VIEWS</TT> instruction or the
2894: name of an associated element type (with an ``s'' added to the end). The
2895: associated element must have been declared in the <TT>ASSOC</TT> section of
2896: the structure schema.</P>
2897: <PRE>
2898: 'PRINT' PrintViewSeq
2899: PrintViewSeq = PrintView < ',' PrintView > ';' .
2900: PrintView = ViewID / ElemID .
2901: </PRE>
2902: <P>
2903: If the <TT>PRINT</TT> instruction is absent, the printing program will print
2904: only the principal view (the first view specified by the <TT>VIEWS</TT>
2905: instruction or the single, unnamed view when there is no <TT>VIEWS</TT>
2906: instruction).</P>
2907: <BLOCKQUOTE class="example">
2908: <P>
2909: <STRONG>Example:</STRONG></P>
2910: <P>
1.3 cvs 2911: Consider a Report presentation using the view declarations from the preceding
2912: example. Suppose we want to print the full text and table of contents views,
2913: but not the Formulas view, which is only useful when editing. In addition,
2914: suppose that we also want to print the bibliographic citations, which are
2915: associated elements (of type <TT>Citation</TT>). A sensible printing order
2916: would be to print the full text then the bibliography and finally the table of
2917: contents. To obtain this result when printing, the presentation schema would
1.1 cvs 2918: say:</P>
2919: <PRE>
2920: PRINT
2921: Full_text, Citations, Table_of_contents;
2922: </PRE>
2923: </BLOCKQUOTE>
2924: </DIV>
2925:
2926: <DIV class="subsection">
1.6 cvs 2927: <H3><A name=sectc424>Counters</A></H3>
1.1 cvs 2928:
2929: <P>
2930: A presentation has a <EM>counter</EM> for each type of number in the
2931: presentation. All counters, and therefore all types of numbers, used in the
2932: schema must be declared after the <TT>COUNTERS</TT> keyword.</P>
2933: <P>
2934: Each counter declaration is composed of a name identifying the counter
2935: followed by a colon and the counting function to be applied to the counter.
2936: The counter declaration ends with a semi-colon.</P>
2937: <P>
2938: The counting function indicates how the counter values will be calculated.
2939: Three types of counting functions are available. The first type is used to
2940: count the elements of a list or aggregate: it assigns to the counter the rank
2941: of the element in the list or aggregate. More precisely, the function</P>
2942: <PRE>
2943: RANK OF ElemID [ LevelAsc ] [ INIT AttrID ]
2944: [ 'REINIT' AttrID ]
2945: </PRE>
2946: <P>
1.5 cvs 2947: indicates that when an element creates, by a creation rule (see the <A
1.6 cvs 2948: href="#sectc4232"><TT>Create</TT> instructions</A>), a presentation box
1.5 cvs 2949: containing the counter value, this value is the rank of the creating element,
2950: if it is of type <TT>ElemID</TT>, otherwise the rank of the first element of
2951: type <TT>ElemID</TT> which encloses the creating element in the logical
1.1 cvs 2952: structure of the document.</P>
2953: <P>
2954: The type name can be preceded by a star in the special case where the
2955: structure schema defines an element of whose <TT>ElemID</TT> is the same as
1.6 cvs 2956: that of an <A href="#sectd3284">inclusion</A> without expansion or with
1.1 cvs 2957: partial expansion. To resolve this ambiguity, the <TT>ElemID</TT> alone
2958: refers to the type defined in the structure schema while the <TT>ElemID</TT>
2959: preceded by a star refers to the included type.</P>
2960: <P>
2961: The type name <TT>ElemID</TT> can be followed by an integer. That number
2962: represents the relative level, among the ancestors of the creating element, of
2963: the element whose rank is asked. If that relative level <I>n</I> is unsigned,
2964: the <I>n</I><SUP>th</SUP> element of type <TT>ElemID</TT> encountered when
2965: travelling the logical structure from the root to the creating element is
2966: taken into account. If the relative level is negative, the logical structure
2967: is travelled in the other direction, from the creating element to the
2968: root.</P>
2969: <P>
2970: The function can end with the keyword <TT>INIT</TT> followed by the name of a
2971: numeric attribute (and only a numeric attribute). Then, the rank of the first
2972: element of the list or aggregate is considered to be the value of this
2973: attribute, rather than the default value of 1, and the rank of the other
2974: elements is shifted accordingly. The attribute which determines the initial
2975: value is searched on the element itself and on its ancestors.</P>
2976: <P>
2977: The function can end with the keyword <TT>REINIT</TT> followed by the name of
2978: a numeric attribute (and only a numeric attribute). Then, if an element to be
2979: counted has this attribute, the counter value for this element is the
2980: attribute value and the following elements are numbered starting from this
2981: value.</P>
2982: <P>
2983: When the <TT>RANK</TT> function is written</P>
2984: <PRE>
2985: RANK OF Page [ ViewID ] [ INIT AttrID ]
2986: </PRE>
2987: <P>
1.5 cvs 2988: (<TT>Page</TT>is a keyword of the P language), the counter takes as its value
2989: the number of the page on which the element which creates the presentation box
2990: containing the number appears. This is done as if the pages of the document
2991: form a list for each view. The counter only takes into account the pages of
2992: the relevant view, that is the view displaying the presentation box whose
2993: contents take the value of the number. However, if the keyword <TT>Page</TT>
2994: is followed by the name of a view (between parentheses), it is the pages of
2995: that view that are taken into account. As in the preceding form, the
2996: <TT>RANK</TT> function applied to pages can end with the <TT>INIT</TT> keyword
2997: followed by the name of a numeric attribute which sets the value of the first
2998: page's number. This attribute must be a local attribute of the document
2999: itself, and not of one of its components.</P>
1.1 cvs 3000: <P>
3001: The second counting function is used to count the occurrences of a certain
3002: element type in a specified context. The instruction</P>
3003: <PRE>
3004: SET n ON Type1 ADD m ON Type2 [ INIT AttrID ]
3005: </PRE>
3006: <P>
1.5 cvs 3007: says that when the document is traversed from beginning to end (in the order
3008: induced by the logical structure), the counter is assigned the value <TT>n</TT>
3009: each time an element of type <TT>Type1</TT> is encountered, no matter
3010: what the current value of the counter, and the value <TT>m</TT> is added to the
3011: current value of the counter each time an element of type <TT>Type2</TT> is
1.1 cvs 3012: encountered.</P>
3013: <P>
3014: As with the <TT>RANK</TT> function, the type names can be preceded by a star
3015: to resolve the ambiguity of included elements.</P>
3016: <P>
3017: If the function ends with the keyword <TT>INIT</TT> followed by the name of an
3018: attribute and if the document possesses this attribute, the value of this
3019: attribute is used in place of <TT>n</TT>. The attribute must be numeric. It
3020: is searched on the element itself and on its ancestors.</P>
3021: <P>
3022: This function can also be used with the <TT>Page</TT> keyword in the place of
3023: <TT>Type1</TT> or <TT>Type2</TT>. In the first case, the counter is
3024: reinitialized on each page with the value <TT>n</TT>, while in the second
3025: case, it is incremented by <TT>m</TT> on each page. As with the preceding
3026: counting function, the word <TT>Page</TT> can be followed by a name between
3027: parentheses. In this case, the name specifies a view whose pages are taken
3028: into account.</P>
3029: <P>
3030: The definition of a counter can contain several <TT>SET</TT> functions and
3031: several <TT>ADD</TT> functions, each with a different value. The total number
3032: of counting functions must not be greater than 6.</P>
3033: <P>
3034: The third counting function is used to count the elements of a certain type
3035: encountered when travelling from the creating element to the root of the
3036: logical structure. The creating element is included if it is of that type.
3037: That function is written</P>
3038: <PRE>
3039: RLEVEL OF Type
3040: </PRE>
3041: <P>
1.5 cvs 3042: where <TT>Type</TT> represents the type of the elements to be counted.</P>
1.1 cvs 3043: <P>
3044: The formal definition of counter declarations is:</P>
3045: <PRE>
3046: 'COUNTERS' CounterSeq
3047: CounterSeq = Counter < Counter > .
3048: Counter = CounterID ':' CounterFunc ';' .
3049: CounterID = NAME .
3050: CounterFunc = 'RANK' 'OF' TypeOrPage [ SLevelAsc ]
3051: [ 'INIT' AttrID ] [ 'REINIT' AttrID ] /
3052: SetFunction < SetFunction >
3053: AddFunction < AddFunction >
3054: [ 'INIT' AttrID ] /
3055: 'RLEVEL' 'OF' ElemID .
3056: SLevelAsc = [ '-' ] LevelAsc .
3057: LevelAsc = NUMBER .
3058: SetFunction = 'SET' CounterValue 'ON' TypeOrPage .
3059: AddFunction = 'ADD' CounterValue 'ON' TypeOrPage .
3060: TypeOrPage = 'Page' [ '(' ViewID ')' ] /
3061: [ '*' ] ElemID .
3062: CounterValue = NUMBER .
3063: </PRE>
3064: <BLOCKQUOTE class="example">
3065: <P>
3066: <STRONG>Example:</STRONG></P>
3067: <P>
1.3 cvs 3068: If the body of a chapter is defined as a sequence of sections in the structure
1.1 cvs 3069: schema:</P>
3070: <PRE>
3071: Chapter_body = LIST OF (Section =
3072: BEGIN
3073: Section_Title = Text;
3074: Section_Body = Paragraphs;
3075: END
3076: );
3077: </PRE>
3078: <P>
3079: the section counter is declared:</P>
3080: <PRE>
3081: SectionCtr : RANK OF Section;
3082: </PRE>
3083: <P>
1.4 cvs 3084: and the display of the section number before the section title is obtained by a
1.6 cvs 3085: <A href="#sectc4232"><TT>CreateBefore</TT> rule</A> attached the
1.4 cvs 3086: <TT>Section_Title</TT> type, which creates a presentation box whose content is
3087: the value of the <TT>SectionCtr</TT> counter (see the <A
1.6 cvs 3088: href="#sectc4231"><TT>Content</TT> instruction</A>).</P>
1.1 cvs 3089: <P>
3090: In order to number the formulas separately within each chapter, the formula
3091: counter is declared:</P>
3092: <PRE>
3093: FormulaCtr : SET 0 ON Chapter ADD 1 ON Formula;
3094: </PRE>
3095: <P>
1.4 cvs 3096: and the display of the formula number in the right margin, alongside each
3097: formula, is obtained by a <TT>CreateAfter</TT> instruction attached to the
3098: <TT>Formula</TT> type, which creates a presentation box whose content is the
3099: value of the <TT>FormulaCtr</TT> counter.</P>
1.1 cvs 3100: <P>
3101: To number the page chapter by chapter, with the first page of each chapter
3102: having the number 1, the counter definition would be</P>
3103: <PRE>
3104: ChapterPageCtr : SET 0 ON Chapter ADD 1 ON Page;
3105: </PRE>
3106: <P>
3107: If there is also a chapter counter</P>
3108: <PRE>
3109: ChapterCtr : RANK OF Chapter;
3110: </PRE>
3111: <P>
1.6 cvs 3112: the <A href="#sectc4231">content</A> of a presentation box created at the top of
1.1 cvs 3113: each page could be defined as:</P>
3114: <PRE>
3115: Content : (VALUE(ChapterCtr, URoman) TEXT '-'
3116: VALUE(ChapterPageCtr, Arabic));
3117: </PRE>
3118: <P>
1.5 cvs 3119: Thus, the presentation box contains the number of the chapter in upper-case
1.4 cvs 3120: roman numerals followed by a hyphen and the number of the page within
3121: the chapter in arabic numerals.</P>
1.1 cvs 3122: </BLOCKQUOTE>
3123: <BLOCKQUOTE class="example">
3124: <P>
3125: <STRONG>Example:</STRONG></P>
3126: <P>
1.3 cvs 3127: To count tables and figures together in a document of the chapter type, a
1.1 cvs 3128: counter could be defined using:</P>
3129: <PRE>
3130: CommonCtr : SET 0 ON Chapter ADD 1 ON Table
3131: ADD 1 ON Figure;
3132: </PRE>
3133: </BLOCKQUOTE>
3134: </DIV>
3135:
3136: <DIV class="subsection">
1.6 cvs 3137: <H3><A name=sectc425>Presentation constants</A></H3>
1.1 cvs 3138:
3139: <P>
3140: Presentation constants are used in the definition of the content of
1.6 cvs 3141: presentation boxes. This content is used in <A href="#sectc426">variable
3142: definitions</A> and in the <A href="#sectc4231"><TT>Content</TT> rule</A>. The
1.1 cvs 3143: only presentation constants which can be used are character strings,
1.2 cvs 3144: mathematical symbols, graphical elements, and pictures, that is to say, base
1.1 cvs 3145: elements.</P>
3146: <P>
3147: Constants can be defined directly in the variables or presentation boxes
3148: (<TT>Content</TT> rule) which use them. But it is only necessary them to
3149: declare once, in the constant declaration section, even though they are used
3150: in many variables or boxes. Thus, each declared constant has a name, which
3151: allows it to be designated whenever it is used, a type (one of the four base
3152: types) and a value (a character string or a single character for mathematical
3153: symbols and graphical elements).</P>
3154: <P>
3155: The constant declarations appear after the keyword <TT>CONST</TT>. Each
3156: declaration is composed of the name of the constant, an equals sign, a keyword
3157: representing its type (<TT>Text</TT>, <TT>Symbol</TT>, <TT>Graphics</TT> or
3158: <TT>Picture</TT>) and the string representing its value. A semi-colon
3159: terminates each declaration.</P>
3160: <P>
3161: In the case of a character string, the keyword <TT>Text</TT> can be followed
3162: by the name of an alphabet (for example, <TT>Greek</TT> or <TT>Latin</TT>) in
3163: which the constant's text should be expressed. If the alphabet name is
3164: absent, the Latin alphabet is used. When the alphabet name is present, only
3165: the first letter of the alphabet name is interpreted. Thus, the words
3166: <TT>Greek</TT> and <TT>Grec</TT> designate the same alphabet. In current
3167: versions of Thot, only the Greek and Latin alphabets are available.</P>
3168: <PRE>
3169: 'CONST' ConstSeq
3170: ConstSeq = Const < Const > .
3171: Const = ConstID '=' ConstType ConstValue ';' .
3172: ConstID = NAME .
3173: ConstType ='Text' [ Alphabet ] / 'Symbol' /
3174: 'Graphics' / 'Picture' .
3175: ConstValue = STRING .
3176: Alphabet = NAME .
3177: </PRE>
3178: <P>
1.5 cvs 3179: For character strings in the Latin alphabet (ISO Latin-1 character set),
1.1 cvs 3180: characters having codes higher than 127 (decimal) are represented by their
3181: code in octal.</P>
3182: <P>
3183: In the case of a symbol or graphical element, the value only contains a single
3184: character, between apostrophes, which indicates the form of the element which
3185: must be drawn in the box whose content is the constant. The symbol or
3186: graphical element takes the dimensions of the box, which are determined by the
1.6 cvs 3187: <TT>Height</TT> and <TT>Width</TT> rules. See <A href="#sectb72">table of
1.1 cvs 3188: codes</A> for the symbols and graphical elements.</P>
3189: <BLOCKQUOTE class="example">
3190: <P>
3191: <STRONG>Example:</STRONG></P>
3192: <P>
1.3 cvs 3193: The constants ``Summary:'' and fraction bar, which were described earlier, are
1.1 cvs 3194: declared:</P>
3195: <PRE>
3196: CONST
3197: SummaryConst = Text 'Summary:';
3198: Bar = Graphics 'h';
3199: </PRE>
3200: </BLOCKQUOTE>
3201: </DIV>
3202:
3203: <DIV class="subsection">
1.6 cvs 3204: <H3><A name=sectc426>Variables</A></H3>
1.1 cvs 3205:
3206: <P>
3207: Variables permit the definition of computed content for presentation boxes. A
3208: variable is associated with a presentation box by a <TT>Content</TT> rule; but
3209: before being used in a <TT>Content</TT> rule, a variable can be defined in the
3210: <TT>VAR</TT> section. It is also possible to define a variable at the time of
3211: its use in a <TT>Content</TT> rule, as can be done with a constant.</P>
3212: <P>
3213: A variable has a name and a value which is a character string resulting from
3214: the concatenation of the values of a sequence of functions. Each variable
3215: declaration is composed of the variable name followed by a colon and the
3216: sequence of functions which produces its value, separated by spaces. Each
3217: declaration is terminated by a semi-colon.</P>
3218: <PRE>
3219: 'VAR' VarSeq
3220: VarSeq = Variable < Variable > .
3221: Variable = VarID ':' FunctionSeq ';' .
3222: VarID = NAME .
3223: FunctionSeq = Function < Function > .
3224: </PRE>
3225: <P>
3226: Several functions are available. The first two return, in the form of a
3227: character string, the current date. <TT>DATE</TT> returns the date in
3228: English, while <TT>FDATE</TT> returns the date in french.</P>
3229: <P>
3230: Two other functions, <TT>DocName</TT> and <TT>DirName</TT>, return the
3231: document name and the directory where the document is stored.</P>
3232: <P>
3233: Function <TT>ElemName</TT> returns the type of the element which created the
3234: presentation box whose contents are the variable.</P>
3235: <P>
3236: Another function simply returns the value of a presentation constant. For any
3237: constant declared in the <TT>CONST</TT> section, it is sufficient to give the
3238: name of the constant. Otherwise, the type and value of the constant must be
1.6 cvs 3239: given, using the same form as in a <A href="#sectc425">constant
1.1 cvs 3240: declaration</A>. If the constant is not of type text, (types <TT>Symbol</TT>,
3241: <TT>Graphics</TT> or <TT>Picture</TT>), it must be alone in the variable
3242: definition; only constants of type <TT>Text</TT> can be mixed with other
3243: functions.</P>
3244: <P>
3245: It is also possible to obtain the value of an attribute, simply by mentioning
3246: the attribute's name. The value of this function is the value of the
3247: attribute for the element which created the presentation box whose contents
3248: are the variable. If the creating element does not have the indicated
3249: attribute, the value is an empty string. In the case of a numeric attribute,
3250: the attribute is translated into a decimal number in arabic numerals. If
3251: another form is desired, the <TT>VALUE</TT> function must be used.</P>
3252: <P>
3253: The last available function returns, as a character string, the value of a
3254: counter, an attribute or a page number. This value can be presented in
3255: different styles. The keyword <TT>VALUE</TT> is followed (between
3256: parentheses) by the name of the counter, the name of the attribute, or the
3257: keyword <TT>PageNumber</TT> and the desired style, the two parameters being
3258: separated by a comma. The style is a keyword which indicates whether the
3259: value should be presented in arabic numerals (<TT>Arabic</TT>), lower-case
3260: roman numerals (<TT>LRoman</TT>), or upper-case roman numerals
3261: (<TT>URoman</TT>), or by an upper-case letter (<TT>Uppercase</TT>) or
3262: lower-case letter (<TT>Lowercase</TT>).</P>
3263: <P>
3264: For a page counter, the keyword <TT>PageNumber</TT> can be followed, between
3265: parentheses, by the name of the view from which to obtain the page number. By
3266: default, the first view declared in the <TT>VIEWS</TT> section is used. The
3267: value obtained is the number of the page on which is found the element that is
3268: using the variable in a <TT>Content</TT> rule.</P>
3269: <P>
3270: For an ordinary counter, the name of the counter can be preceded by the
3271: keyword <TT>MaxRangeVal</TT> or <TT>MinRangeVal</TT>. These keywords mean
3272: that the value returned by the function is the maximum (minimum resp.) value
3273: taken by the counter in the whole document, not the value for the element
3274: concerned by the function.</P>
3275: <PRE>
1.6 cvs 3276: Function = 'DATE' / 'FDATE' /
1.1 cvs 3277: 'DocName' / 'DirName' /
3278: 'ElemName' / 'AttributeName' /
3279: ConstID / ConstType ConstValue /
3280: AttrID /
3281: 'VALUE' '(' PageAttrCtr ','
3282: CounterStyle ')' .
1.6 cvs 3283: PageAttrCtr = 'PageNumber' [ '(' ViewID ')' ] /
1.1 cvs 3284: [ MinMax ] CounterID / AttrID .
3285: CounterStyle = 'Arabic' / 'LRoman' / 'URoman' /
3286: 'Uppercase' / 'Lowercase' .
1.6 cvs 3287: MinMax = 'MaxRangeVal' / 'MinRangeVal' .
1.1 cvs 3288: </PRE>
3289: <BLOCKQUOTE class="example">
3290: <P>
3291: <STRONG>Example:</STRONG></P>
3292: <P>
1.3 cvs 3293: To make today's date appear at the top of the first page of a report, a <A
1.6 cvs 3294: href="#sectc4232"><TT>CREATE</TT> rule</A> associated with the Report_Title
1.3 cvs 3295: element type generates a presentation box whose content (specified by the
3296: <TT>Content</TT> rule of that presentation box) is the variable:</P>
1.1 cvs 3297: <PRE>
3298: VAR
3299: Todays_date : TEXT 'Version of ' DATE;
3300: </PRE>
3301: <P>
3302: To produce, before each section title, the chapter number (in upper-case roman
3303: numerals) followed by the section number (in arabic numerals), two counters
3304: must be defined:</P>
3305: <PRE>
3306: COUNTERS
3307: ChapterCtr : RANK OF Chapter;
3308: SectionCtr : RANK OF Section;
3309: </PRE>
3310: <P>
1.4 cvs 3311: and the Section_Title element must create a presentation box whose content is
1.1 cvs 3312: the variable</P>
3313: <PRE>
3314: VAR
3315: SectionNum : VALUE (ChapterCtr, URoman) TEXT '-'
3316: VALUE (SectionCtr, Arabic);
3317: </PRE>
3318: <P>
3319: In order to make the page number on which each section begins appear in the
3320: table of contents view next to the section title, each Section_Title element
3321: must create a presentation box, visible only in the table of contents view,
3322: whose content is the variable:</P>
3323: <PRE>
3324: VAR
3325: TitlePageNume :
3326: VALUE (PageNumber(Full_text), Arabic);
3327: </PRE>
3328: </BLOCKQUOTE>
3329: </DIV>
3330:
3331: <DIV class="subsection">
1.6 cvs 3332: <H3><A name=sectc427>Default presentation rules</A></H3>
1.1 cvs 3333:
3334: <P>
3335: In order to avoid having to specify, for each element type defined in the
3336: structure schema, values for every one of the numerous presentation
3337: parameters, the presentation schema allows the definition of a set of default
3338: presentation rules. These rules apply to all the boxes of the elements
3339: defined in the structure schema and to the presentation boxes and page layout
3340: boxes defined in the presentation schema. Only rules which differ from these
3341: default need to be specified in other sections of the presentation schema.</P>
3342: <P>
3343: For the primary view, the default rules can define every presentation
3344: parameter, but not the <A href="#presfunct">presentation functions</A> or the
1.6 cvs 3345: <A href="#sectc4223">linebreaking conditions</A> (the <TT>NoBreak1</TT>,
1.1 cvs 3346: <TT>NoBreak2</TT>, and <TT>Gather</TT> rules).</P>
3347: <P>
3348: In a presentation schema, the default presentation rules section is optional;
3349: in this case, the <TT>DEFAULT</TT> keyword is also absent and the following
3350: rules are considered to be the default rules:</P>
3351: <PRE>
1.6 cvs 3352: Visibility: Enclosing =;
3353: VertRef: * . Left;
3354: HorizRef: Enclosed . HRef;
3355: Height: Enclosed . Height;
3356: Width: Enclosed . Width;
3357: VertPos: Top = Previous . Bottom;
3358: HorizPos: Left = Enclosing . Left;
3359: VertOverflow: No;
1.1 cvs 3360: HorizOverflow: No;
1.6 cvs 3361: Size: Enclosing =;
3362: Style: Enclosing =;
3363: Font: Enclosing =;
3364: Underline: Enclosing =;
3365: Thickness: Enclosing =;
3366: Indent: Enclosing =;
3367: LineSpacing: Enclosing =;
3368: Adjust: Enclosing =;
3369: Justify: Enclosing =;
3370: Hyphenate: Enclosing =;
3371: PageBreak: Yes;
3372: LineBreak: Yes;
3373: InLine: Yes;
3374: Depth: 0;
3375: LineStyle: Enclosing =;
3376: LineWeight: Enclosing =;
3377: FillPattern: Enclosing =;
3378: Background: Enclosing =;
3379: Foreground: Enclosing =;
1.1 cvs 3380: </PRE>
3381: <P>
3382: If other values are desired for the default rules, they must be defined
3383: explicitly in the default rules section. In fact, it is only necessary to
3384: define those default rules which differ from the ones above, since the rules
3385: above will be used whenever a rule is not explicitly named.</P>
3386: <P>
3387: Default rules for views other than the primary view can also be specified.
3388: Otherwise, the default rules for the primary views are applied to the other
3389: views.</P>
3390: <P>
1.6 cvs 3391: Default rules are expressed in the same way as <A href="#sectc4215">explicit
1.1 cvs 3392: rules for document elements</A>.</P>
3393: </DIV>
3394:
3395: <DIV class="subsection">
1.6 cvs 3396: <H3><A name=sectc428>Presentation and page layout boxes</A></H3>
1.1 cvs 3397:
3398: <P>
3399: The presentation process uses elements which are not part of the logical
3400: structure of the document, such as pages (which are the page layout boxes) or
3401: alternatively, rules, numbers, or words introducing certain parts of the
3402: document, such as ``Summary'', ``Appendices'', ``Bibliography'', etc. (which
3403: are presentation boxes).</P>
3404: <P>
3405: After the word <TT>BOXES</TT>, each presentation or page layout box is defined
3406: by its name and a sequence of presentation rules which indicate how they must
3407: be displayed. These rules are the same as those which define the boxes
3408: associated with element of the logical structure of the document, with a
1.6 cvs 3409: single exception, the <A href="#sectc4231"><TT>Content</TT> rule</A> which is
1.1 cvs 3410: used only to specify the content of presentation boxes. The content of boxes
3411: associated with elements of the document structure is defined in each document
3412: or object and thus is not specified in the presentation schema, which applies
3413: to all documents or objects of a class.</P>
3414: <P>
3415: Among the rules which define a presentation box, certain ones can refer to
3416: another presentation box (for example, in their positional rules). If the
3417: designated box is defined after the box which designates it, a
3418: <TT>FORWARD</TT> instruction followed by the name of the designated box must
3419: appear before the designation.</P>
3420: <PRE>
1.6 cvs 3421: 'BOXES' BoxSeq
1.1 cvs 3422: BoxSeq = Box < Box > .
3423: Box ='FORWARD' BoxID ';' /
3424: BoxID ':' ViewRuleSeq .
3425: BoxID = NAME .
3426: </PRE>
3427: </DIV>
3428:
3429: <DIV class="subsection">
1.6 cvs 3430: <H3><A name=sectc429>Presentation of structured elements</A></H3>
1.1 cvs 3431:
3432: <P>
3433: After the words <TT>RULES</TT>, the presentation schema gives the presentation
3434: rules that apply to the elements whose types are defined in the structure
3435: schema. Only those rules which differ from the <A
1.6 cvs 3436: href="#sectc427">default</A> must be specified in the <TT>RULES</TT>
1.1 cvs 3437: section.</P>
3438: <P>
3439: The rule definitions for each element type are composed of the name of the
3440: element type (as specified in the structure schema) followed by a colon and
3441: the set of rules specific to that type.</P>
3442: <P>
3443: The type name can be preceded by a star in the special case where the
1.6 cvs 3444: structure schema defines an <A href="#sectd3284">inclusion</A> without
1.1 cvs 3445: expansion (or with partial expansion) of a type with the same name as an
3446: element of defined in the structure schema.</P>
3447: <P>
1.6 cvs 3448: In the case where the element is a <A href="#sectd3285">mark pair</A>, but only in
1.1 cvs 3449: this case, the type name can be preceded by the keywords <TT>First</TT> or
3450: <TT>Second</TT>. These keywords indicate whether the rules that follow apply
3451: to the first or second mark of the pair.</P>
3452: <PRE>
1.6 cvs 3453: 'RULES' PresentSeq
1.1 cvs 3454: PresentSeq = Present < Present > .
1.6 cvs 3455: Present = [ '*' ] [ FirstSec ] ElemID ':'
3456: ViewRuleSeq .
3457: FirstSec = 'First' / 'Second' .
1.1 cvs 3458: </PRE>
3459: <P>
3460: A presentation schema can define presentation rules for base elements, which
3461: are defined implicitly in the structure schemas. In the English version of
3462: the presentation schema compiler, the base type names are the same as in the S
3463: language, but they are terminated by the <TT>_UNIT</TT> suffix:
3464: <TT>TEXT_UNIT</TT>, <TT>PICTURE_UNIT</TT>, <TT>SYMBOL_UNIT</TT>,
1.2 cvs 3465: <TT>GRAPHICS_UNIT</TT>. The base type names are written in upper-case
3466: letters.</P>
1.1 cvs 3467: </DIV>
3468:
3469: <DIV class="subsection">
1.6 cvs 3470: <H3><A name=sectc4210>Logical attribute presentation</A></H3>
1.1 cvs 3471:
3472: <P>
3473: After the keyword <TT>ATTRIBUTES</TT>, all attributes which are to have some
3474: effect on the presentation of the element to which they are attached must be
3475: mentioned, along with the corresponding presentation rules. This is true for
3476: both global attributes (which can be attached to all element types) and local
3477: attributes (which can only be attached to certain element types).</P>
3478: <P>
3479: Also mentioned in this section are attributes which imply an effect on
3480: elements in the subtree of the element to which they are attached. The
3481: presentation of these descendants can be modified as a function of the value
3482: of the attribute which they inherit, just as if it was attached to them
3483: directly.</P>
3484: <P>
3485: The specification for each attribute includes the attribute's name, followed
3486: by an optional value specification and, after a colon, a set of rules. The
3487: set of rules must contain at least one rule.</P>
3488: <P>
3489: When there is no value specification, the rules are applied to all elements
3490: which carry the attribute, no matter what their value. When the rules must
3491: only apply when the attribute has certain values, these values must be
3492: specified. Thus, the same attribute can appear in the <TT>ATTRIBUTES</TT>
3493: section several times, with each appearance having a different value
3494: specification. However, reference attributes never have a value specification
3495: and, as a result, can only appear once in the <TT>ATTRIBUTES</TT> section.</P>
3496: <P>
3497: To specify that the presentation rules apply to some of the descendants of the
3498: element having the attribute, the name of the affected element type is given,
3499: between parentheses, after the attribute name. This way, the presentation
3500: rules for the attribute will be applied to the element having the attribute,
3501: if it is of the given type, and to all of its descendants of the given type.
1.6 cvs 3502: In the case where this type is a <A href="#sectd3285">mark pair</A>, but only in
1.1 cvs 3503: this case, the type name can be preceded by the keywords <TT>First</TT> or
3504: <TT>Second</TT>. These keywords indicate whether the rules that follow apply
3505: to the first or second mark of the pair. If the rule must apply to several
3506: different element types, the specification must be repeated for each element
3507: type.</P>
3508: <P>
3509: The specification of values for which the presentation rules will be applied
3510: varies according to the type of the attribute:</P>
3511: <DL>
3512: <DT>numeric attribute</DT>
1.2 cvs 3513: <DD>If the rules are to apply for one value of the attribute, then the
3514: attribute name is followed by an equals sign and this value. If the rules are
3515: to apply for all values less than (or greater than) a threshold value,
3516: non-inclusive, the attribute name followed by a '<' sign (or a '>' sign,
3517: respectively) and the threshold value. If the rules must apply to a range of
3518: values, the attribute name is followed by the word '<TT>IN</TT>' and the
3519: two bounds of the range, enclosed in brackets and separated by two
3520: periods ('<TT>..</TT>'). In the case of ranges, the values of the bounds
3521: are included in the range.
1.1 cvs 3522: <P>
3523: The threshold value in the comparisons can be the value of an attribute
3524: attached to an ancestor element. In this case, the attribute name is given
3525: instead of a constant value.</P>
3526: <P>
3527: It is also possible to write rules which apply only when a comparison between
3528: two different attributes of the element's ancestors is true. In this case, the
3529: first attribute name is followed by a comparison keyword and the name of the
3530: second attribute. The comparison keywords are <TT>EQUAL</TT> (simple
3531: equality), <TT>LESS</TT> (non-inclusive less than), and <TT>GREATER</TT>
3532: (non-inclusive greater than).</P>
3533: </DD>
3534: <DT>text attribute</DT>
1.2 cvs 3535: <DD>If the rules are to apply for one value of the attribute, then the
3536: attribute name is followed by an equals sign and this value.
1.1 cvs 3537: </DD>
3538: <DT>reference attribute</DT>
1.2 cvs 3539: <DD>There is never a value specification; the rules apply no matter what
1.1 cvs 3540: element is designated by the attribute.
3541: </DD>
3542: <DT>enumerated attribute</DT>
1.2 cvs 3543: <DD>If the rules are to apply for one value of the attribute, then the
3544: attribute name is followed by an equals sign and this value.
1.1 cvs 3545: </DD>
3546: </DL>
3547: <P>
3548: The order in which the rules associated with a numeric attribute are defined
3549: is important. When multiple sets of rules can be applied, the first set
3550: declared is the one used.</P>
3551: <P>
3552: Rules for attributes have priority over both default rules and rules
3553: associated with element types. The attribute rules apply to the element to
3554: which the attribute is attached. It is the rules which apply to the
3555: surrounding elements (and especially to the descendants) which determine the
3556: effect of the attribute rules on the environment ( and especially on the
3557: terminal elements of the structure).</P>
3558: <PRE>
3559: 'ATTRIBUTES' PresAttrSeq
3560: PresAttrSeq = PresAttr < PresAttr > .
3561: PresAttr = AttrID [ '(' [ FirstSec ] ElemID ')' ]
3562: [ AttrRelation ] ':' ViewRuleSeq .
3563: AttrID = NAME .
3564: AttrRelation ='=' AttrVal /
3565: '>' [ '-' ] MinValue /
3566: '<' [ '-' ] MaxValue /
3567: 'IN' '[' [ '-' ] LowerBound '..'
3568: [ '-' ] UpperBound ']' /
3569: 'GREATER' AttrID /
3570: 'EQUAL' AttrID /
3571: 'LESS' AttrID .
3572: AttrVal = [ '-' ] EqualNum / EqualText /
3573: AttrValue .
3574: MinValue = NUMBER .
3575: MaxValue = NUMBER .
3576: LowerBound = NUMBER .
3577: UpperBound = NUMBER.
3578: EqualNum = NUMBER .
3579: EqualText = STRING .
3580: AttrValue = NAME .
3581: </PRE>
3582: <P>
3583: In presentation rules associated with a numeric attribute (and only in such
3584: rules), the attribute name can be used in place of a numeric value. In this
3585: case, the value of the attribute is used in the application of the rule. Thus,
3586: the attribute can represent a relation between the size of two boxes, the
3587: height and width of a box, the height of an area where page breaks are
3588: prohibited, the distance between two boxes, the position of the reference axis
3589: of a box, the interline spacing, the indentation of the first line, the
3590: visibility, the depth (z-order), or the character set.</P>
3591: <P>
3592: The presentation rules associated with reference attributes, it is possible to
3593: use the element designated by the attribute as a reference box in a positional
3594: or extent rule. This element is represented in the <A
1.6 cvs 3595: href="#sectc4218">position</A> or <A href="#sectc4219">extent</A> rule by the
1.1 cvs 3596: keyword <TT>Referred</TT>.</P>
3597: <BLOCKQUOTE class="example">
3598: <P>
3599: <STRONG>Example:</STRONG></P>
3600: <P>
1.3 cvs 3601: In all structure schemas, there is a global Language attribute defined as
1.1 cvs 3602: follows:</P>
3603: <PRE>
3604: ATTR
3605: Language = TEXT;
3606: </PRE>
3607: <P>
1.4 cvs 3608: The following rules would make French text be displayed in roman characters and
1.1 cvs 3609: English text be displayed in italics:</P>
3610: <PRE>
3611: ATTRIBUTES
3612: Language = 'French' :
1.6 cvs 3613: Style : Roman;
1.1 cvs 3614: Language = 'English' :
1.6 cvs 3615: Style : Italics;
1.1 cvs 3616: </PRE>
3617: <P>
1.4 cvs 3618: Using these rules, when the user puts the Language attribute with the value
3619: 'English' on the summary of a document, every character string (terminal
3620: elements) contained in the summary are displayed in italics. See the <A
1.7 cvs 3621: href="#sectd42252"><TT>Style</TT> rule</A>.</P>
1.1 cvs 3622: </BLOCKQUOTE>
3623: <BLOCKQUOTE class="example">
3624: <P>
3625: <STRONG>Example:</STRONG></P>
3626: <P>
1.3 cvs 3627: A numeric attribute representing the importance of the part of the document to
1.1 cvs 3628: which it is attached can be defined:</P>
3629: <PRE>
3630: ATTR
3631: Importance = INTEGER;
3632: </PRE>
3633: <P>
1.4 cvs 3634: In the presentation schema, the importance of an element is reflected in the
1.1 cvs 3635: choice of character size, using the following rules.</P>
3636: <PRE>
3637: ATTRIBUTES
3638: Importance < 2 :
3639: Size : 1;
3640: Importance IN [2..4] :
3641: Size : Importance;
3642: Importance = 10 :
3643: Size : 5;
3644: Importance > 4 :
3645: Size : 4;
3646: </PRE>
3647: <P>
1.4 cvs 3648: Thus, the character size corresponds to the value of the Importance attribute;
1.1 cvs 3649: its value is</P>
3650: <UL>
1.2 cvs 3651: <LI>the value of the Importance attribute when the value is between 2 and 4
1.1 cvs 3652: (inclusive),
3653: <LI>1, when the value of the Importance attribute is less than 2,
1.5 cvs 3654: <LI>4, when the value of the Importance attribute is greater than 4,
1.1 cvs 3655: <LI>5, when the value of the Importance attribute is 10.
3656: </UL>
3657: <P>
1.4 cvs 3658: The last case (value 5) must be defined before the case which handles all
3659: Importance values greater than 4, because the two rules are not disjoint and
3660: the first one defined will have priority. Otherwise, when the Importance
1.1 cvs 3661: attribute has value 10, the font size will be 4.</P>
3662: </BLOCKQUOTE>
3663: <BLOCKQUOTE class="example">
3664: <P>
3665: <STRONG>Example:</STRONG></P>
3666: <P>
1.3 cvs 3667: Suppose the structure defines a list element which can have an attribute
1.1 cvs 3668: defining the type of list (numbered or not):</P>
3669: <PRE>
3670: STRUCT
3671: list (ATTR list_type = enumeration, dash)
3672: = LIST OF (list_item = TEXT);
3673: </PRE>
3674: <P>
1.4 cvs 3675: Then, the presentation schema could use the attribute placed on the list
3676: element to put either a dash or a number before the each element of the
1.1 cvs 3677: list:</P>
3678: <PRE>
3679: ATTRIBUTES
3680: list_type (list_item) = enumeration :
3681: CreateBefore (NumberBox);
3682: list_type (list_item) = dash :
3683: CreateBefore (DashBox);
3684: </PRE>
3685: </BLOCKQUOTE>
3686: <BLOCKQUOTE class="example">
3687: <P>
3688: <STRONG>Example:</STRONG></P>
3689: <P>
1.3 cvs 3690: Suppose that two attributes are defined in the structure schema. The first is
3691: a numeric global attribute called ``version''. The other is a local attribute
3692: defined on the root of the document called ``Document_version'':</P>
1.1 cvs 3693: <PRE>
3694: STRUCTURE Document
3695: ATTR
3696: version = INTEGER;
3697: STRUCT
3698: Document (ATTR Document_version = INTEGER) =
3699: BEGIN
3700: SomeElement ;
3701: ...
3702: SomeOtherElement ;
3703: END ;
3704: ...
3705: </PRE>
3706: <P>
1.4 cvs 3707: These attributes can be used in the presentation schema to place change bars in
3708: the margin next to elements whose version attribute has a value equal to the
3709: Document_version attribute of the root and to place a star in margin of
3710: elements whose version attribute is less than the value of the root's
1.1 cvs 3711: Document_version attribute:</P>
3712: <PRE>
3713: ATTRIBUTES
3714: version EQUAL Document_version :
3715: CreateBefore (ChangeBarBox) ;
3716: version LESS Document_version :
3717: CreateBefore (StarBox) ;
3718: </PRE>
3719: </BLOCKQUOTE>
3720: </DIV>
3721:
3722: <DIV class="subsection">
1.6 cvs 3723: <H3><A name=sectc4212>Value transmission rules</A></H3>
1.1 cvs 3724:
3725: <P>
3726: The last section of a presentation schema, which is optional, serves to
3727: defines the way in which a document transmits certain values to its
3728: sub-documents. A sub-document is an document <A
3729: href="#inclusion">included</A> without expansion or with partial expansion.
3730: The primary document can transmit to its sub-documents the values of certain
3731: counters or the textual content of certain of its elements, as a function of
3732: their type.</P>
3733: <P>
3734: The sub-documents receive these values in attributes which must be defined in
3735: their structure schema as local attributes of the root element. The types of
3736: these attributes must correspond to the type of the value which they receive:
3737: numeric attributes for receiving the value of a counter, textual attributes
3738: for receiving the content of an element.</P>
3739: <P>
3740: In the structure schema of the primary document, there appears at the end,
3741: after the <TT>TRANSMIT</TT> keyword, a sequence of transmission rules. Each
3742: rule begins with the name of the counter to transmit or of the element type
3743: whose textual content will be transmitted. This name is followed by the
3744: keyword <TT>To</TT> and the name of the attribute of the sub-document to which
3745: the value is transmitted. The sub-document class is indicated between
3746: parentheses after the name of the attribute. The transmission rule ends with
3747: a semicolon.</P>
3748: <PRE>
3749: TransmitSeq = Transmit < Transmit > .
3750: Transmit = TypeOrCounter 'To' ExternAttr
3751: '(' ElemID ')' ';' .
3752: TypeOrCounter = CounterID / ElemID .
3753: ExternAttr = NAME .
3754: </PRE>
3755: <BLOCKQUOTE class="example">
3756: <P>
3757: <STRONG>Example:</STRONG></P>
3758: <P>
1.3 cvs 3759: Consider a Book document class which includes instances of the Chapter document
1.1 cvs 3760: class. These classes might have the following schemas:</P>
3761: <PRE>
3762: STRUCTURE Book
3763: STRUCT
3764: Book = BEGIN
3765: Title = Text;
3766: Body = LIST OF (Chapter INCLUDED);
3767: END;
3768: ...
3769:
3770: STRUCTURE Chapter
3771: STRUCT
3772: Chapter (ATTR FirstPageNum = Integer;
3773: ChapterNum = Integer;
3774: CurrentTitle = Text) =
1.6 cvs 3775: BEGIN
3776: ChapterTitle = Text;
3777: ...
3778: END;
1.1 cvs 3779: ...
3780: </PRE>
3781: <P>
3782: Then the presentation schema for books could define chapter and page counters.
3783: The following transmission rules in the book presentation schema would
3784: transmit values for the three attributes defined at the root of each chapter
3785: sub-document.</P>
3786: <PRE>
3787: PRESENTATION Book;
3788: VIEWS
3789: Full_text;
3790: COUNTERS
3791: ChapterCtr: Rank of Chapter;
3792: PageCtr: Rank of Page(Full_text);
3793: ...
3794: TRANSMIT
3795: PageCtr TO FirstPageNum(Chapter);
3796: ChapterCtr TO ChapterNum(Chapter);
3797: Title TO CurrentTitle(Chapter);
3798: END
3799: </PRE>
3800: <P>
3801: Thus, each chapter included in a book can number its pages as a function of
3802: the number of pages preceding it in the book, can make the chapter's number
3803: appear before the number of each of its sections, or can place the title of
3804: the book at the top of each page.</P>
3805: </BLOCKQUOTE>
3806: </DIV>
3807:
3808: <DIV class="subsection">
1.6 cvs 3809: <H3><A name=sectc4213>Presentation rules</A></H3>
1.1 cvs 3810:
3811: <P>
3812: Whether defining the appearance of a presentation or page layout box, an
3813: element type, or an attribute value, the set of presentation rules that apply
3814: is always defined in the same way.</P>
3815: <P>
3816: Normally, a set of presentation rules is placed between the keywords
3817: <TT>BEGIN</TT> and <TT>END</TT>, the keyword <TT>END</TT> being followed by a
3818: semicolon. The first section of this block defines the rules that apply to
1.6 cvs 3819: the primary view, if the <A href="#sectc427">default rules</A> are not
1.1 cvs 3820: completely suitable. Next comes the rules which apply to specific other
3821: views, with a rule sequence for each view for which the default rules are not
3822: satisfactory. If the default rules are suitable for the non-primary views,
3823: there will not be any specific rules for these views. If there is only one
3824: rule which applies to all views then the keywords <TT>BEGIN</TT> and
3825: <TT>END</TT> need not appear.</P>
3826: <P>
3827: For each view, it is only necessary to specify those rules which differ from
3828: the default rules for the view, so that for certain views (or even all views),
3829: there may be no specific rules.</P>
3830: <P>
3831: The specific rules for a non-primary view are introduced by the <A
3832: name="inkeyword"><TT>IN</TT> keyword</A>, followed by the view name. The
3833: rules for that view follow, delimited by the keywords <TT>BEGIN</TT> and
3834: <TT>END</TT>, or without these two keywords when there is only one rule.</P>
3835: <P>
3836: <STRONG>Note:</STRONG> the view name which follows the <TT>IN</TT> keyword
3837: must not be the name of the primary view, since the rules for that view are
3838: found before the rules for the other views.</P>
3839: <P>
3840: Within each block concerning a view, other blocks can appear, delimited by the
3841: same keywords <TT>BEGIN</TT> and <TT>END</TT>. Each of these blocks gathers
3842: the presentation rules that apply, for a given view, only when a given
3843: condition is satisfied. Each block is preceded by a condition introduced by
3844: the <TT>IF</TT> keyword. If such a conditional block contains only one rule,
3845: the keywords <TT>BEGIN</TT> and <TT>END</TT> can be omitted.</P>
3846: <P>
3847: Although the syntax allows any presentation rule to appear in a conditional
1.6 cvs 3848: block, only <A href="#sectc4232">creation rules</A> are allowed after any
1.1 cvs 3849: condition; other rules are allowed only after conditions <TT>Within</TT> and
3850: ElemID. In addition, the following rules cannot be conditional:
3851: <TT>PageBreak, LineBreak, Inline, Gather</TT>.</P>
3852: <P>
3853: For a given view, the rules that apply without any condition must appear
3854: before the first conditional block. If some rules apply only when none of the
3855: specified condition holds, they are grouped in a block preceded by the keyword
3856: <TT>Otherwise</TT>, and that block must appear after the last conditionnal
3857: block concerning the same view.</P>
3858: <PRE>
3859: ViewRuleSeq = 'BEGIN' < RulesAndCond > < ViewRules >
3860: 'END' ';' /
3861: ViewRules / CondRules / Rule .
3862: RulesAndCond = CondRules / Rule .
3863: ViewRules = 'IN' ViewID CondRuleSeq .
3864: CondRuleSeq = 'BEGIN' < RulesAndCond > 'END' ';' /
3865: CondRules / Rule .
3866: CondRules = CondRule < CondRule >
3867: [ 'Otherwise' RuleSeq ] .
3868: CondRule = 'IF' ConditionSeq RuleSeq .
3869: RulesSeq = 'BEGIN' Rule < Rule > 'END' ';' /
3870: Rule .
3871: </PRE>
3872: <BLOCKQUOTE class="example">
3873: <P>
3874: <STRONG>Example:</STRONG></P>
3875: <P>
1.3 cvs 3876: The following rules for a report's title make the title visible in the primary
3877: view and invisible in the table of contents and in the formula views (see the
1.6 cvs 3878: <A href="#sectc4224"><TT>Visibility</TT> rule</A>).</P>
1.1 cvs 3879: <PRE>
3880: Title : BEGIN
3881: Visibility : 1;
3882: ... {Other rules for the primary view}
3883: IN Table_of_contents
3884: Visibility : 0;
3885: IN Formulas
3886: Visibility : 0;
3887: END;
3888: </PRE>
3889: </BLOCKQUOTE>
3890: </DIV>
3891:
3892: <DIV class="subsection">
1.6 cvs 3893: <H3><A name=sectc4214>Conditions applying to presentation rules</A></H3>
1.1 cvs 3894:
3895: <P>
3896: Many conditions can be applied to presentation rules. Conditions allow
3897: certain presentation rules to apply only in certain cases. These conditions
3898: can be based on the structural position of the element. They can be based on
3899: whether the element has references, and what type of references, whether the
3900: element has attributes, whether the element is empty or not. They can also be
3901: based on the value of a counter.</P>
3902: <P>
3903: It is possible to specify several conditions which must all be true for the
3904: rules to apply.</P>
3905: <P>
3906: A set of conditions is specified by the <TT>IF</TT> keyword. This keyword is
3907: followed by the sequence of conditions, separated by the <TT>AND</TT> keyword.
3908: Each condition is specified by a keyword which defines the condition type. In
3909: some cases, the keyword is followed by other data, which specify the condition
3910: more precisely.</P>
3911: <P>
3912: An elementary condition can be negative; it is then preceded by the
3913: <TT>NOT</TT> keyword.</P>
3914: <P>
3915: When the presentation rule(s) controlled by the condition apply to a reference
3916: element or a reference attribute, an elementary condition can also apply to
3917: element referred by this reference. The <TT>Target</TT> keyword is used for
3918: that purpose. It must appear before the keyword defining the condition
3919: type.</P>
3920: <PRE>
1.6 cvs 3921: CondRule ='IF' ConditionSeq RuleSeq .
1.1 cvs 3922: ConditionSeq = Condition < 'AND' Condition > .
3923: Condition = [ 'NOT' ] [ 'Target' ] ConditionElem .
3924: ConditionElem ='First' / 'Last' /
3925: [ 'Immediately' ] 'Within' [ NumParent ]
3926: ElemID [ ExtStruct ] /
3927: ElemID /
3928: 'Referred' / 'FirstRef' / 'LastRef' /
3929: 'ExternalRef' / 'InternalRef' / 'CopyRef' /
3930: 'AnyAttributes' / 'FirstAttr' / 'LastAttr' /
3931: 'UserPage' / 'StartPage' / 'ComputedPage' /
3932: 'Empty' /
3933: '(' [ MinMax ] CounterName CounterCond ')' /
3934: CondPage '(' CounterID ')' .
3935: NumParent = [ GreaterLess ] NParent .
1.6 cvs 3936: GreaterLess ='>' / '<' .
1.1 cvs 3937: NParent = NUMBER.
1.6 cvs 3938: ExtStruct ='(' ElemID ')' .
1.1 cvs 3939: CounterCond ='<' MaxCtrVal / '>' MinCtrVal /
3940: '=' EqCtrVal /
3941: 'IN' '[' ['-'] MinCtrBound '.' '.'
3942: ['-'] MaxCtrBound ']' .
3943: PageCond ='Even' / 'Odd' / 'One' .
3944: MaxCtrVal = NUMBER .
3945: MinCtrVal = NUMBER .
3946: EqCtrVal = NUMBER .
3947: MaxCtrBound = NUMBER .
3948: MinCtrBound = NUMBER .
3949: </PRE>
3950:
3951: <DIV class="subsubsection">
1.6 cvs 3952: <H4><A name=sectd42141>Conditions based on the logical position of the element</A></H4>
1.1 cvs 3953:
3954: <P>
3955: The condition can be on the position of the element in the document's logical
3956: structure tree. It is possible to test whether the element is the first
3957: (<TT>First</TT>) or last (<TT>Last</TT>) among its siblings or if it is not
3958: the first (<TT>NOT First</TT>) or not the last (<TT>NOT Last</TT>). These
1.6 cvs 3959: conditions can be associated only with <A href="#sectc4232">creation
1.1 cvs 3960: rules</A>.</P>
3961: <P>
3962: It is also possible to test if the element is contained in an element of a
3963: given type (<TT>Within</TT>) or if it is not (<TT>NOT Within</TT>). The type
3964: is indicated after the keyword <TT>Within</TT>. If that element type is
3965: defined in a structure schema which is not the one which corresponds to the
3966: presentation schema, the type name of this element must be followed, between
3967: parentheses, by the name of the structure schema which defines it.</P>
3968: <P>
3969: If the keyword <TT>Within</TT> is preceded by <TT>Immediately</TT>, the
3970: condition is satisfied only if the <EM>parent</EM> element has the type
3971: indicated. If the word <TT>Immediately</TT> is missing, the condition is
3972: satisfied if any <EM>ancestor</EM> has the type indicated.</P>
3973: <P>
3974: An integer <I>n</I> can appear between the keyword <TT>Within</TT> and the
3975: type. It specifies the number of ancestors of the indicated type that must be
3976: present for the condition to be satisfied. If the keyword
3977: <TT>Immediately</TT> is also present, the <I>n</I> immediate ancestors of the
3978: element must have the indicated type. The integer <I>n</I> must be positive
3979: or zero. It can be preceded by <TT><</TT> or <TT>></TT> to indicate a
3980: maximum or minimum number of ancestors. If these symbols are missing, the
3981: condition is satisfied only if it exists exactly <I>n</I> ancestors. When
3982: this number is missing, it is equivalent to > 0.</P>
3983: <P>
3984: If the condition applies to presentation rules associated with an attribute,
3985: in the <TT>ATTRIBUTES</TT> section of the presentation schema, the condition
3986: can be simply an element name. Presentation rules are then executed only if
3987: the attribute is attached to an element of that type. The keyword <TT>NOT</TT>
3988: before the element name indicates that the presentation rules must be executed
3989: only if the element is not of the type indicated.</P>
3990: </DIV>
3991:
3992: <DIV class="subsubsection">
1.6 cvs 3993: <H4><A name=sectd42142>Conditions on references</A></H4>
1.1 cvs 3994:
3995: <P>
3996: References may be taken into account in conditions, which can be based on the
3997: fact that the element, or one of its ancestors, is designated by a at least
3998: one reference (<TT>Referred</TT>) or by none (<TT>NOT Referred</TT>).</P>
3999: <P>
4000: If the element or attribute to which the condition is attached is a reference,
4001: the condition can be based on the fact that it acts as the first reference to
4002: the designated element (<TT>FirstRef</TT>), or as the last (<TT>LastRef</TT>),
4003: or as a reference to an element located in another document
4004: (<TT>ExternalRef</TT>) or in the same document (<TT>InternalRef</TT>).</P>
4005: <P>
4006: The condition can also be based on the fact that the element is an <A
4007: href="#inclusion">inclusion</A>. This is noted (<TT>CopyRef</TT>).</P>
4008: <P>
4009: Like all conditions, conditions on references can be inverted by the
4010: <TT>NOT</TT> keyword. These conditions can be associated only with <A
1.6 cvs 4011: href="#sectc4232">creation rules</A>.</P>
1.1 cvs 4012: </DIV>
4013:
4014: <DIV class="subsubsection">
1.6 cvs 4015: <H4><A name=sectd42143>Conditions on logical attributes</A></H4>
1.1 cvs 4016:
4017: <P>
4018: The condition can be based on the presence or absence of attributes associated
4019: with the element, no matter what the attributes or their values. The
4020: <TT>AnyAttributes</TT> keyword expresses this condition.</P>
4021: <P>
4022: If the condition appears in the presentation rules of an attribute, the
4023: <TT>FirstAttr</TT> and <TT>LastAttr</TT> keywords can be used to indicate that
4024: the rules must only be applied if this attribute is the first attribute for
4025: the element or if it is the last (respectively). These conditions can also be
4026: inverted by the <TT>NOT</TT> keyword. These conditions can be associated only
1.6 cvs 4027: with <A href="#sectc4232">creation rules</A>.</P>
1.1 cvs 4028: <P>
4029: It is also possible to apply certain presentation rules only when the element
4030: being processed or one of its ancestors has a certain attribute, perhaps with
4031: a certain value. This can be done in the <A
1.6 cvs 4032: href="#sectc4210"><TT>ATTRIBUTES</TT> section</A>.</P>
1.1 cvs 4033: </DIV>
4034:
4035: <DIV class="subsubsection">
1.6 cvs 4036: <H4><A name=sectd42144>Conditions on page breaks</A></H4>
1.1 cvs 4037:
4038: <P>
4039: The page break base type (and only this type) can use the following
4040: conditions: <TT>ComputedPage</TT>, <TT>StartPage</TT>, and <TT>UserPage</TT>.
4041: The <TT>ComputedPage</TT> condition indicates that the presentation rule(s)
4042: should apply if the page break was created automatically by Thot; the
4043: <TT>StartPage</TT> condition is true if the page break is generated before the
4044: element by the <TT>Page</TT> rule; and the <TT>UserPage</TT> condition applies
4045: if the page break was inserted by the user.</P>
4046: <P>
1.6 cvs 4047: These conditions can be associated only with <A href="#sectc4232">creation
1.1 cvs 4048: rules</A>.</P>
4049: </DIV>
4050:
4051: <DIV class="subsubsection">
1.6 cvs 4052: <H4><A name=sectd42145>Conditions on the element's content</A></H4>
1.1 cvs 4053:
4054: <P>
4055: The condition can be based on whether or not the element is empty. An element
4056: which has no children or whose leaves are all empty is considered to be empty
4057: itself. This condition is expressed by the <TT>Empty</TT> keyword, optionally
4058: preceded by the <TT>NOT</TT> keyword. This condition can be associated only
1.6 cvs 4059: with <A href="#sectc4232">creation rules</A>.</P>
1.1 cvs 4060: </DIV>
4061:
4062: <DIV class="subsubsection">
1.6 cvs 4063: <H4><A name=sectd42146>Conditions on counters</A></H4>
1.1 cvs 4064:
4065: <P>
4066: Presentation rules can apply when the counter's value is one, is even or odd,
4067: is equal, greater than or less than a given value or falls in a range of
4068: values. This is particularly useful for creating header and footer boxes.
1.6 cvs 4069: These conditions can be associated only with <A href="#sectc4232">creation
1.1 cvs 4070: rules</A>.</P>
4071: <P>
4072: To compare the value of a counter to a given value, a comparison is given
4073: between parentheses. The comparison is composed of the counter name followed
4074: by an equals, greater than, or less than sign and the value to which the
4075: counter will be compared. A test for whether or not a counter's value falls
4076: in a range also appears within parentheses. In this case, the counter name is
4077: followed by the <TT>IN</TT> keyword and the range definition within brackets.
4078: The <TT>Even</TT>, <TT>Odd</TT> and <TT>One</TT> are used to test a counter's
4079: value and are followed by the counter name between parentheses.</P>
4080: <P>
4081: The list of possible conditions on counters is:</P>
4082: <DL>
4083: <DT><TT>Even (Counter)</TT></DT>
1.2 cvs 4084: <DD>the box is created only if the counter has an even value.
1.1 cvs 4085: </DD>
4086: <DT><TT>Odd (Counter)</TT></DT>
1.2 cvs 4087: <DD>the box is created only if the counter has an odd value.
1.1 cvs 4088: </DD>
4089: <DT><TT>One (Counter)</TT></DT>
1.2 cvs 4090: <DD>the box is created only the counter's value is 1.
1.1 cvs 4091: </DD>
4092: <DT><TT>NOT One (Counter)</TT></DT>
1.5 cvs 4093: <DD>the box is created, unless the counter's value is 1.
1.1 cvs 4094: </DD>
4095: <DT><TT>(Counter < Value)</TT></DT>
1.5 cvs 4096: <DD>the box is created only if the counter's value is less than Value.
1.1 cvs 4097: </DD>
4098: <DT><TT>(Counter > Value)</TT></DT>
1.5 cvs 4099: <DD>the box is created only if the counter's value is greater than Value.
1.1 cvs 4100: </DD>
4101: <DT><TT>(Counter = Value)</TT></DT>
1.5 cvs 4102: <DD>the box is created only if the counter's value is equal to Value.
1.1 cvs 4103: </DD>
4104: <DT><TT>NOT (Counter = Value)</TT></DT>
1.5 cvs 4105: <DD>the is created only if the counter's value is different than Value.
1.1 cvs 4106: </DD>
4107: <DT><TT>(Counter IN [MinValue..MaxValue])</TT></DT>
1.5 cvs 4108: <DD>the box is created only if the counter's value falls in the range bounded
4109: by MinValue and MaxValue (inclusive).
1.1 cvs 4110: </DD>
4111: <DT><TT>NOT (Counter IN [MinValue..MaxValue])</TT></DT>
1.5 cvs 4112: <DD>the box is created only if the value of the counter does not fall in the
4113: range bounded by MinValue and MaxValue (inclusive).
1.1 cvs 4114: </DD>
4115: </DL>
4116: <P>
4117: <STRONG>Note:</STRONG> the <TT>NOT Even</TT> and <TT>NOT Odd</TT> conditions
4118: are syntactically correct but can be expressed more simply by <TT>Odd</TT> and
4119: <TT>Even</TT>, respectively.</P>
4120: </DIV>
4121: </DIV>
4122:
4123: <DIV class="subsection">
1.6 cvs 4124: <H3><A name=sectc4215>A presentation rule</A></H3>
1.1 cvs 4125:
4126: <P>
4127: A presentation rule defines either a presentation parameter or presentation
4128: function. The parameters are:</P>
4129: <UL>
1.2 cvs 4130: <LI>the position of the vertical and horizontal reference axes of the box,
1.1 cvs 4131: <LI>the position of the box in relation to other boxes,
4132: <LI>the height or width of the box, with overflow exceptions,
1.2 cvs 4133: <LI>the characteristics of the lines contained in the box: linespacing,
1.1 cvs 4134: indentation of the first line, justification, hyphenation,
4135: <LI>the conditions for breaking the box across pages,
1.2 cvs 4136: <LI>the characteristics of the characters contained in the box: size, font,
1.1 cvs 4137: style, underlining,
1.2 cvs 4138: <LI>the depth of the box among overlapping boxes (often called stacking
4139: order),
4140: <LI>the characteristics of graphic elements contained in the box: style and
1.1 cvs 4141: thickness of lines, fill pattern for closed objects,
1.2 cvs 4142: <LI>the colors in text, graphics, pictures, and symbols contained in the box
4143: are displayed or printed,
1.1 cvs 4144: <LI>for presentation boxes only, the contents of the box.
4145: </UL>
4146: <P>
4147: The <A name="presfunct">presentation functions</A>are:</P>
4148: <UL>
4149: <LI>the creation of a presentation box
4150: <LI>the line-breaking or page-breaking style,
4151: <LI>the copying of another box.
4152: </UL>
4153: <P>
4154: For each box and each view, every presentation parameter is defined once and
1.6 cvs 4155: only once, either explicitly or by the <A href="#sectc427">default
1.1 cvs 4156: rules</A>. In contrast, presentation functions are not obligatory and can
4157: appear many times for the same element. for example an element can create
4158: many presentation boxes. Another element may not use any presentation
4159: functions.</P>
4160: <P>
4161: Each rule defining a presentation parameter begins with a keyword followed by
4162: a colon. the keyword indicates the parameter which is the subject of the rule.
4163: After the keyword and the colon, the remainder of the rule varies. All rules
4164: are terminated by a semicolon.</P>
4165: <PRE>
1.6 cvs 4166: Rule = PresParam ';' / PresFunc ';' .
4167: PresParam ='VertRef' ':' PositionHoriz /
4168: 'HorizRef' ':' PositionVert /
4169: 'VertPos' ':' VPos /
4170: 'HorizPos' ':' HPos /
4171: 'Height' ':' Dimension /
4172: 'Width' ':' Dimension /
4173: 'VertOverflow' ':' Boolean /
1.1 cvs 4174: 'HorizOverflow' ':' Boolean /
1.6 cvs 4175: 'LineSpacing' ':' DistanceInherit /
4176: 'Indent' ':' DistanceInherit /
4177: 'Adjust' ':' AdjustInherit /
4178: 'Justify' ':' BoolInherit /
4179: 'Hyphenate' ':' BoolInherit /
4180: 'PageBreak' ':' Boolean /
4181: 'LineBreak' ':' Boolean /
4182: 'InLine' ':' Boolean /
4183: 'NoBreak1' ':' AbsDist /
4184: 'NoBreak2' ':' AbsDist /
4185: 'Gather' ':' Boolean /
4186: 'Visibility' ':' NumberInherit /
4187: 'Size' ':' SizeInherit /
4188: 'Font' ':' NameInherit /
4189: 'Style' ':' StyleInherit /
4190: 'Underline' ':' UnderLineInherit /
4191: 'Thickness' ':' ThicknessInherit /
4192: 'Depth' ':' NumberInherit /
4193: 'LineStyle' ':' LineStyleInherit /
4194: 'LineWeight' ':' DistanceInherit /
4195: 'FillPattern' ':' NameInherit /
4196: 'Background' ':' NameInherit /
4197: 'Foreground' ':' NameInherit .
4198: 'Content' ':' VarConst .
1.1 cvs 4199: PresFunc = Creation '(' BoxID ')' /
4200: 'Line' /
4201: 'NoLine' /
4202: 'Page' '(' BoxID ')' /
4203: 'Copy' '(' BoxTypeToCopy ')' .
4204: </PRE>
4205: </DIV>
4206:
4207: <DIV class="subsection">
1.6 cvs 4208: <H3><A name=sectc4216>Box axes</A></H3>
1.1 cvs 4209:
4210: <P>
4211: The position of the middle axes <TT>VMiddle</TT> and <TT>HMiddle</TT> in
4212: relation to their box is always calculated automatically as a function of the
4213: height and width of the box and is not specified by the presentation rules. In
4214: the presentation schema, these middle axes are used only to position their box
4215: with respect to another by specifying the distance between the middle axis and
1.6 cvs 4216: an axis or a side of another box (see the <A href="#sectc4218">relative
1.1 cvs 4217: position</A>).</P>
4218: <P>
4219: The reference axes of a box are also used to position their box in relation to
4220: another, but in contrast to the middle axes, the presentation schema must make
4221: their position explicit, either in relation to a side or the middle axis of
4222: the box itself, or in relation to an axis of an enclosed box.</P>
4223: <P>
4224: Only boxes of base elements have predefined reference axes. For character
4225: string boxes, the horizontal reference axis is the baseline of the characters
4226: (the line which passes immediately under the upper-case letters, ignoring the
4227: letter Q) and the vertical reference axis is at the left edge of the first
4228: character of the string.</P>
4229: <P>
4230: The positions of a box's reference axes are defined by the <TT>VertRef</TT>
4231: and <TT>HorizRef</TT> rules which specify the <A href="#distance">distance</A>
4232: between the reference axis and an axis or parallel side of the same box or of
4233: an enclosed box.</P>
4234: <PRE>
1.6 cvs 4235: 'VertRef' ':' PositionHoriz
1.1 cvs 4236: 'HorizRef' ':' PositionVert
4237: </PRE>
4238: <BLOCKQUOTE class="example">
4239: <P>
4240: <STRONG>Example:</STRONG></P>
4241: <P>
1.3 cvs 4242: If, in the structure schema for mathematical formulas, the fraction element is
1.1 cvs 4243: defined by</P>
4244: <PRE>
4245: Fraction = BEGIN
4246: Numerator = Expression;
4247: Denominator = Expression;
4248: END;
4249: </PRE>
4250: <P>
1.3 cvs 4251: then the horizontal reference axis of the fraction can be positioned on top of
1.1 cvs 4252: the denominator by the rule:</P>
4253: <PRE>
4254: Fraction :
4255: BEGIN
4256: HorizRef : Enclosed Denominator . Top;
4257: ...
4258: END;
4259: </PRE>
4260: <P>
4261: To put the horizontal reference axis of a column at its middle:</P>
4262: <PRE>
4263: Column :
4264: BEGIN
4265: HorizRef : * . HMiddle;
4266: ...
4267: END;
4268: </PRE>
4269: </BLOCKQUOTE>
4270: </DIV>
4271:
4272: <DIV class="subsection">
1.6 cvs 4273: <H3><A name=sectc4217>Distance units</A></H3>
1.1 cvs 4274:
4275: <P>
4276: Some distances and dimensions appear in many rules of a presentation schema,
4277: especially in position rules (<TT>VertPos, HorizPos</TT>), in extent rules for
4278: boxes (<TT>Height, Width</TT>), in rules defining lines (<TT>LineSpacing,
4279: Indent</TT>), in rules controlling pagination (<TT>NoBreak1, NoBreak2</TT>)
4280: and in rules specifying the thickness of strokes (<TT>LineWeight</TT>).</P>
4281: <P>
4282: In all these rules, the distance or extent can be expressed</P>
4283: <UL>
1.2 cvs 4284: <LI>either in relative units, which depend on the size of the characters in
4285: the current font: height of the element's font or height of the letter 'x',
4286: <LI>or in absolute units: centimeter, millimeter, inch, typographer's point,
1.1 cvs 4287: pica or pixel.
4288: </UL>
4289: <P>
1.5 cvs 4290: Units can be chosen freely. Thus, it is possible to use relative units in one
4291: rule, centimeters in the next rule, and typographer's points in another.</P>
1.1 cvs 4292: <P>
4293: Absolute units are used to set rigid rules for the appearance of documents. In
4294: contrast, relative units allow changes of scale. The editor lets the value of
4295: relative units be changed dynamically. Such changes affect every box using
4296: relative units simultaneously and in the same proportion. Changing the value
4297: of the relative units affects the size of the characters and graphical
4298: elements, and the size of the boxes and the distances between them.</P>
4299: <P>
4300: A <A name="distance">distance</A> or extent is specified by a number, which
4301: may be followed by one or more spaces and a units keyword. When there is no
4302: units keyword, the number specifies the number of relative units, where a
4303: relative unit is the height of a character in the current font (an em). When
4304: the number is followed by a units keyword, the keyword indicates the type of
4305: absolute units:</P>
4306: <UL>
4307: <LI><TT>em</TT>: height of the element's font,
4308: <LI><TT>ex</TT>: height of the letter 'x',
4309: <LI><TT>cm</TT>: centimeter,
4310: <LI><TT>mm</TT>: millimeter,
4311: <LI><TT>in</TT>: inch (1 in = 2.54 cm),
4312: <LI><TT>pt</TT>: point (1 pt = 1/72 in),
4313: <LI><TT>pc</TT>: pica (1 pc = 12 pt),
4314: <LI><TT>px</TT>: pixel.
4315: </UL>
4316: <P>
4317: Whatever the chosen unit, relative or absolute, the number is not necessarily
4318: an integer and may be expressed in fixed point notation (using the American
4319: convention of a period to express the decimal point).</P>
4320: <P>
4321: If the distance appears in a presentation rule for a numeric attribute, the
4322: number can be replaced by the name of an attribute. In this case, the value
4323: of the attribute is used. Obviously, the attribute name cannot be followed by
4324: a decimal point and a fractional part, but it can be followed a units keyword.
4325: However, the choice of units is limited to em, ex, pt and px.</P>
4326: <PRE>
4327: Distance = [ Sign ] AbsDist .
4328: Sign ='+' / '-' .
4329: AbsDist = IntegerOrAttr [ '.' DecimalPart ]
4330: [ Unit ].
4331: IntegerOrAttr = IntegerPart / AttrID .
4332: IntegerPart = NUMBER .
4333: DecimalPart = NUMBER .
4334: Unit ='em' / 'ex' / 'cm' / 'mm' / 'in' / 'pt' /
4335: 'pc' / 'px' / '%' .
4336: </PRE>
4337: <BLOCKQUOTE class="example">
4338: <P>
4339: <STRONG>Example:</STRONG></P>
4340: <P>
1.3 cvs 4341: The following rules specify that a box has a height of 10.5 centimeters and a
1.1 cvs 4342: width of 5.3 ems:</P>
4343: <PRE>
4344: Height : 10.5 cm;
1.6 cvs 4345: Width : 5.3;
1.1 cvs 4346: </PRE>
4347: </BLOCKQUOTE>
4348: </DIV>
4349:
4350: <DIV class="subsection">
1.6 cvs 4351: <H3><A name=sectc4218>Relative positions</A></H3>
1.1 cvs 4352:
4353: <P>
4354: The positioning of boxes uses the eight axes and sides, the sides generally
4355: being used to define the juxtapositioning (vertical or horizontal) of boxes,
4356: the middle axes being used to define centering, and the reference axes being
4357: used for alignment.</P>
4358: <P>
4359: Two rules allow a box to placed relative to other boxes. The <TT>VertPos</TT>
4360: rule positions the box vertically. The <TT>HorizPos</TT> rule positions the
4361: box horizontally. It is possible that a box's position could be entirely
4362: determined by other boxes positioned relative to it. In this case, the
4363: position is implicit and the word <TT>nil</TT> can be used to specify that no
4364: position rule is needed. Otherwise, an explicit rule must be given by
4365: indicating the axis or side which defines the position of the box, followed by
4366: an equals sign and the distance between between this axis or side and a
4367: parallel axis or side of another box, called the reference box. The box for
4368: which the rule is written will be positioned relative to the reference
4369: box.</P>
4370: <PRE>
1.6 cvs 4371: 'VertPos' ':' VPos
4372: 'HorizPos' ':' HPos
4373: HPos = 'nil' / VertAxis '=' HorizPosition
4374: [ 'UserSpecified' ].
4375: VPos = 'nil' / HorizAxis '=' VertPosition
4376: [ 'UserSpecified' ].
1.1 cvs 4377: VertAxis = 'Left' / 'VMiddle' / 'VRef' / 'Right' .
4378: HorizAxis = 'Top' / 'HMiddle' / 'HRef' / 'Bottom' .
4379: </PRE>
4380: <P>
4381: The reference box is an adjacent box: enclosing, enclosed or adjacent. When a
4382: rule is associated with a reference type attribute (and only in this case), it
4383: can be a box of the element designated by the attribute. The reference box
4384: can be either a presentation box previously defined in the <TT>BOXES</TT>
4385: section of the schema and created by a creation function, or the box
4386: associated with a structured element.</P>
4387: <P>
4388: The structural position of the reference box (relative to the box for which
4389: the rule is being written) is indicated by a keyword: <TT>Enclosing</TT>,
4390: <TT>Enclosed</TT>, or, for sibling boxes, <TT>Previous</TT> or <TT>Next</TT>.
4391: The reference attributes, or presentation boxes created by a reference
4392: attribute, the <TT>Referred</TT> keyword may be used to designate the element
4393: which the reference points to. The keyword <TT>Creator</TT> can be used in
4394: rules for presentation boxes to designate the box of the element which created
4395: the presentation box. Finally, the <TT>Root</TT> keyword can be used to
4396: designate the root of the document.</P>
4397: <P>
4398: When the keyword is ambiguous, it is followed by a name of a type or
4399: presentation box which resolves the ambiguity (the <TT>Creator</TT> and
4400: <TT>Root</TT> keywords are never ambiguous). If this name is not given, then
4401: the first box encountered is used as the reference box. It is also possible to
4402: use just the name of a type or presentation box without an initial keyword. In
4403: this case, a sibling having that name will be used. If the name is preceded
4404: by the keyword <TT>NOT</TT>, then the reference box will be the first box
4405: whose type is not the named one. In place of the box or type name, the
4406: keywords <TT>AnyElem</TT> and <TT>AnyBox</TT> can be used, representing
4407: respectively, any structured element box and any presentation box. A type
4408: name may be preceded by a star in order to resolve the ambiguity in the
4409: special case where the structure schema defines an <A
1.6 cvs 4410: href="#sectd3284">inclusion</A> without expansion (or with partial expansion)
1.1 cvs 4411: of the same type as an element of the scheme. For mark pairs (and only for <A
1.6 cvs 4412: href="#sectd3285">mark pairs</A>) the type name <EM>must</EM> be preceded by the
1.1 cvs 4413: <TT>First</TT> or <TT>Second</TT> keyword, which indicates which of the two
4414: marks of the pair should be used as the reference box.</P>
4415: <P>
4416: The star character ('<TT>*</TT>') used alone designates the box to which the
4417: rule applies (in this case, it is obviously useless to specify the type of the
4418: reference box).</P>
4419: <P>
4420: The keywords <TT>Enclosing</TT> and <TT>Enclosed</TT> can be used no matter
4421: what constructor defines the type to which the rule applies. When applied to
4422: the element which represents the entire document, <TT>Enclosing</TT>
4423: designates the window or page in which the document's image is displayed for
4424: the view to which the rule applies. A box or type name without a keyword is
4425: used for aggregate elements and designates another element of the same
4426: aggregate. It can also be used to designate a presentation or page layout
4427: box. The keywords <TT>Previous</TT> and <TT>Next</TT> are primarily used to
4428: denote list elements, but can also be used to denote elements of an
4429: aggregate.</P>
4430: <P>
4431: In the position rule, the structural position relative to the reference box is
4432: followed, after a period, by the name of an axis or side. The rule specifies
4433: its node's position as being some distance from this axis or side of the
4434: reference box. If this distance is zero, then the distance does not appear in
4435: the rule. Otherwise, it does appear as a positive or negative number (the
4436: sign is required for negative numbers). The sign takes into account the
4437: orientation of the coordinate axes: for top to bottom for the vertical axis
4438: and from left to right for the horizontal axis. Thus, a negative distance in
4439: a vertical position indicates that the side or axis specified in the rule is
4440: above the side or axis of the reference box.</P>
4441: <P>
4442: The distance can be followed by the <TT>UserSpecified</TT> keyword (even if
4443: the distance is nil and does not appear, the <TT>UserSpecified</TT> keyword
4444: can be used). It indicates that when the element to which the rule applies is
4445: being created, the editor will ask the user to specify the distance himself,
4446: using the mouse. In this case, the distance specified in the rule is a
4447: default distance which is suggested to the user but can be modified. The
4448: <TT>UserSpecified</TT> keyword can be used either in the vertical position
4449: rule, the horizontal position rule, or both.</P>
4450: <PRE>
4451: VertPosition = Reference '.' HorizAxis [ Distance ] .
4452: HorizPosition = Reference '.' VertAxis [ Distance ] .
4453: Reference ='Enclosing' [ BoxTypeNot ] /
4454: 'Enclosed' [ BoxTypeNot ] /
4455: 'Previous' [ BoxTypeNot ] /
4456: 'Next' [ BoxTypeNot ] /
4457: 'Referred' [ BoxTypeNot ] /
4458: 'Creator' /
4459: 'Root' /
4460: '*' /
4461: BoxOrType .
4462: BoxOrType = BoxID /
4463: [ '*' ] [ FirstSec ] ElemID /
4464: 'AnyElem' / 'AnyBox' .
4465: BoxTypeNot = [ 'NOT' ] BoxOrType .
4466: </PRE>
4467: <BLOCKQUOTE class="example">
4468: <P>
4469: <STRONG>Example:</STRONG></P>
4470: <P>
1.5 cvs 4471: If a <A name="expos1">report</A> is defined by the following
1.3 cvs 4472: structure schema:</P>
1.1 cvs 4473: <PRE>
4474: Report = BEGIN
1.6 cvs 4475: Title = Text;
4476: Summary = Text;
4477: Keywords = Text;
4478: ...
4479: END;
1.1 cvs 4480: </PRE>
4481: <P>
4482: then the presentation schema could contain the rules:</P>
4483: <PRE>
4484: Report : BEGIN
1.6 cvs 4485: VertPos : Top = Enclosing . Top;
4486: HorizPos : Left = Enclosing . Left;
4487: ...
4488: END;
1.1 cvs 4489: </PRE>
4490: <P>
1.3 cvs 4491: These rules place the <A name="reportexample">report</A> in the upper left
4492: corner of the enclosing box, which is the window in which the document is being
1.1 cvs 4493: edited.</P>
4494: <PRE>
1.6 cvs 4495: Title : BEGIN
4496: VertPos : Top = Enclosing . Top + 1;
4497: HorizPos : VMiddle = Enclosing . VMiddle;
4498: ...
4499: END;
1.1 cvs 4500: </PRE>
4501: <P>
1.3 cvs 4502: The top of the title is one line (a line has the height of the characters of
4503: the title) from the top of the report, which is also the top of the editing
4504: window. The title is centered horizontally in the window (see <A
1.1 cvs 4505: href="#posdim">figure</A>).</P>
4506: <PRE>
1.6 cvs 4507: Summary : BEGIN
1.1 cvs 4508: VertPos : Top = Title . Bottom + 1.5;
4509: HorizPos : Left = Enclosing . Left + 2 cm;
4510: ...
4511: END;
4512: </PRE>
4513: <P>
1.3 cvs 4514: The top of the summary is place a line and a half below the bottom of the title
1.1 cvs 4515: and is shifted two centimeters from the side of the window.</P>
4516: </BLOCKQUOTE>
4517: <BLOCKQUOTE class="example">
4518: <P>
4519: <STRONG>Example:</STRONG></P>
4520: <P>
1.3 cvs 4521: Suppose there is a <A name="expos2">Design</A> logical structure which contains
1.1 cvs 4522: graphical elements:</P>
4523: <PRE>
4524: Design = LIST OF (ElemGraph = GRAPHICS);
4525: </PRE>
4526: <P>
1.3 cvs 4527: The following rules allow the user to freely choose the position of each
1.1 cvs 4528: element when it is created:</P>
4529: <PRE>
4530: ElemGraph =
4531: BEGIN
4532: VertPos : Top = Enclosing . Top + 1 cm UserSpecified;
4533: HorizPos: Left = Enclosing . Left UserSpecified;
4534: ...
4535: END;
4536: </PRE>
4537: <P>
1.3 cvs 4538: Thus, when a graphical element is created, its default placement is at the left
4539: of the window and 1 cm from the top, but the user can move it immediately,
1.1 cvs 4540: simply by moving the mouse.</P>
4541: </BLOCKQUOTE>
4542: </DIV>
4543:
4544: <DIV class="subsection">
1.6 cvs 4545: <H3><A name=sectc4219>Box extents</A></H3>
1.1 cvs 4546:
4547: <P>
4548: The extents (height and width) of each box are defined by the two rules
4549: <TT>Height</TT> and <TT>Width</TT>. There are three types of extents: fixed,
4550: relative, and elastic.</P>
4551:
4552: <DIV class="subsubsection">
1.6 cvs 4553: <H4><A name=sectd42191>Fixed extents</A></H4>
1.1 cvs 4554:
4555: <P>
4556: A fixed dimension sets the height or width of the box independently of all
1.6 cvs 4557: other boxes. It is expressed in <A href="#sectc4217">distance units</A>. The
1.1 cvs 4558: extent can be followed by the <TT>UserSpecified</TT> keyword which indicates
4559: that when the element to which the rule applies is being created, the editor
4560: will ask the user to specify the extent himself, using the mouse. In this
4561: case, the extent specified in the rule is a default extent which is suggested
4562: to the user but can be modified. The <TT>UserSpecified</TT> keyword can be
4563: used either in the <TT>Height</TT> rule, the <TT>Width</TT> rule, or both.</P>
4564: <P>
4565: A fixed extent rule can be ended by the <TT>Min</TT> keyword, which signifies
4566: that the indicated value is a minimum, and that, if the contents of the box
4567: require it, a larger extent is possible.</P>
4568: <PRE>
4569: 'Height' ':' Dimension
4570: 'Width' ':' Dimension
4571: Dimension = AbsDist [ 'UserSpecified' ] [ 'Min' ] /
4572: ...
4573: </PRE>
4574: <BLOCKQUOTE class="example">
4575: <P>
4576: <STRONG>Example:</STRONG></P>
4577: <P>
1.3 cvs 4578: Continuing with the <A href="#expos2">previous example</A>, it is possible to
4579: allow the user to choose the size of each graphical element as it is
1.1 cvs 4580: created:</P>
4581: <PRE>
4582: ElemGraph : BEGIN
1.6 cvs 4583: Width : 2 cm UserSpecified;
1.1 cvs 4584: Height : 1 cm UserSpecified;
4585: ...
4586: END;
4587: </PRE>
4588: <P>
4589: Thus, when a graphical element is create, it is drawn by default with a width
4590: of 2 cm and a height of 1 cm, but the user is free to resize it immediately
4591: with the mouse.</P>
4592: <PRE>
4593: Summary : BEGIN
4594: Height : 5 cm Min;
4595: ...
4596: END;
4597: Keywords : BEGIN
4598: VertPos : Top = Summary . Bottom;
4599: ...
4600: END;
4601: </PRE>
4602: </BLOCKQUOTE>
4603: </DIV>
4604:
4605: <DIV class="subsubsection">
1.6 cvs 4606: <H4><A name=sectd42192>Relative extents</A></H4>
1.1 cvs 4607:
4608: <P>
4609: A relative extent determines the extent as a function of the extent of another
4610: box, just as a relative position places a box in relation to another. The
4611: reference box in an extent rule is designated using the same syntax as is used
4612: in a relative position rule. It is followed by a period and a <TT>Height</TT>
4613: or <TT>Width</TT> keyword, depending on the extent being referred to. Next
4614: comes the relation between the extent being defined and the extent of the
4615: reference box. This relation can be either a percentage or a difference.</P>
4616: <P>
4617: A percentage is indicated by a star (the multiplication symbol) followed by
4618: the numeric percentage value (which may be greater than or less than 100) and
4619: the percent (`%') character. A difference is simply indicated by a signed
4620: difference.</P>
4621: <P>
4622: If the rule appears in the presentation rules of a numeric attribute, the
4623: percentage value can be replaced by the name of the attribute. This attribute
4624: is then used as a percentage. The attribute can also be used as part of a <A
4625: href="#distance">difference</A>.</P>
4626: <P>
4627: Just as with a fixed extent, a relative extent rule can end with the
4628: <TT>Min</TT> keyword, which signifies that the extent is a minimum and that,
4629: if the contents of the box require it, a larger extent is possible.</P>
4630: <P>
4631: A special case of relative extent rules is:</P>
4632: <PRE>
4633: Height : Enclosed . Height;
4634: </PRE>
4635: <P>
4636: or</P>
4637: <PRE>
4638: Width : Enclosed . Width;
4639: </PRE>
4640: <P>
1.5 cvs 4641: which specifies that the box has a height (or width) such that it encloses all
4642: the boxes which it contains, excluding boxes having a rule <TT>VertOverflow:
4643: Yes;</TT> or <TT>HorizOverflow: Yes;</TT>.</P>
1.1 cvs 4644: <P>
4645: <STRONG>Note:</STRONG> character strings (type <TT>TEXT_UNIT</TT>) generally
4646: must use the sum of the widths of the characters which compose them as their
4647: width, which is expressed by the rule:</P>
4648: <PRE>
4649: TEXT_UNIT :
1.6 cvs 4650: Width : Enclosed . Width;
1.1 cvs 4651: </PRE>
4652: <P>
1.5 cvs 4653: If this rule is not the default <TT>Width</TT> rule, it must be given
4654: explicitly in the <TT>RULES</TT> section which defines the presentation rules
4655: of the logical elements.</P>
1.1 cvs 4656: <PRE>
4657: 'Height' ':' Extent
4658: 'Width' ':' Extent
4659: Extent = Reference '.' HeightWidth [ Relation ]
4660: [ 'Min' ] / ...
4661: HeightWidth ='Height' / 'Width' .
4662: Relation ='*' ExtentAttr '%' / Distance .
4663: ExtentAttr = ExtentVal / AttrID .
4664: ExtentVal = NUMBER .
4665: </PRE>
4666: <BLOCKQUOTE class="example">
4667: <P>
4668: <STRONG>Example:</STRONG></P>
4669: <P>
1.3 cvs 4670: Completing the <A href="#expos1">above example</A>, it is possible to specify
4671: that the report takes its width from the editing window and its height from the
4672: size of its contents (this can obviously be greater than that of the
1.1 cvs 4673: window):</P>
4674: <PRE>
4675: Report : BEGIN
4676: Width : Enclosing . Width;
4677: Height : Enclosed . Height;
4678: ...
4679: END;
4680: </PRE>
4681: <P>
1.3 cvs 4682: Then, the following rules make the title occupy 60% of the width of the report
4683: (which is that of the window) and is broken into centered lines of this width
1.6 cvs 4684: (see the <A href="#sectc4222"><TT>Line</TT> rule</A>).</P>
1.1 cvs 4685: <PRE>
4686: Title : BEGIN
4687: Width : Enclosing . Width * 60%;
4688: Height : Enclosed . Height;
4689: Line;
4690: Adjust : VMiddle;
4691: ...
4692: END;
4693: </PRE>
4694: <P>
1.5 cvs 4695: The summary occupy the entire width of the window, with the exception of a 2 cm
1.1 cvs 4696: margin reserved by the horizontal position rule:</P>
4697: <PRE>
4698: Summary : BEGIN
4699: Width : Enclosing . Width - 2 cm;
4700: Height : Enclosed . Height;
4701: ...
4702: END;
4703: </PRE>
4704: <P>
4705: This set of rules, plus the <A href="#reportexample">position rules given
4706: above</A>, produce the layout of boxes shown in the following<A
4707: href="#posdim">figure</A>.</P>
4708:
4709: <DIV class="figure">
4710: <HR>
4711: <PRE>
4712: -------------------------------------------------------------
4713: | Window and Report ^ |
4714: | | 1 line |
4715: | v |
4716: | ------------------------------------- |
4717: | | | |
4718: : 20% : Title : 20% :
4719: :<--------->: :<--------->:
4720: : : 60% : :
4721: : :<--------------------------------->: :
4722: | | | |
4723: | ------------------------------------- |
4724: | ^ |
4725: | | 1.5 line |
4726: | | |
4727: | v |
4728: | ---------------------------------------------------|
4729: | 2 cm | |
4730: |<------>| Summary |
4731: : : :
4732: </PRE>
4733: <P align=center>
4734: <EM><A name="posdim">Box position and extent</A><EM></EM></EM></P>
4735: <HR>
4736: </DIV>
4737: </BLOCKQUOTE>
4738: </DIV>
4739:
4740: <DIV class="subsubsection">
1.6 cvs 4741: <H4><A name=sectd42193>Elastic extents</A></H4>
1.1 cvs 4742:
4743: <P>
4744: The last type of extent is the elastic extent. Either one or both extents can
4745: be elastic. A box has an elastic extent when two opposite sides are linked by
4746: distance constraints to two sides or axes of other boxes.</P>
4747: <P>
4748: One of the sides of the elastic box is linked by a position rule
4749: (<TT>VertPos</TT> or <TT>HorizPos</TT>) to a neighboring box. The other side
4750: is link to another box by a <TT>Height</TT> or <TT>Width</TT> rule, which
4751: takes the same form as the position rule. For the elastic box itself, the
4752: notions of sides (left or right, top or bottom) are fuzzy, since the movement
4753: of either one of the two reference boxes can, for example, make the left side
4754: of the elastic box move to the right of its right side. This is not
4755: important. The only requirement is that the two sides of the elastic box used
4756: in the position and extent rule are opposite sides of the box.</P>
4757: <PRE>
1.6 cvs 4758: 'Height' ':' Extent
4759: 'Width' ':' Extent
4760: Extent = HPos / VPos / ...
1.1 cvs 4761: </PRE>
4762: <BLOCKQUOTE class="example">
4763: <P>
4764: <STRONG>Example:</STRONG></P>
4765: <P>
1.3 cvs 4766: Suppose we want to draw an elastic arrow or line between the middle of the
4767: bottom side of box A and the upper left corner of box B. To do this, we would
4768: define a graphics box whose upper left corner coincides with the middle of the
4769: bottom side of A (a position rule) and whose lower right corner coincides with
4770: with the upper left corner of B (dimension rules):</P>
1.1 cvs 4771: <PRE>
4772: LinkedBox :
4773: BEGIN
1.6 cvs 4774: VertPos : Top = A .Bottom;
1.1 cvs 4775: HorizPos : Left = A . VMiddle;
1.6 cvs 4776: Height : Bottom = B . Top;
4777: Width : Right = B . Left;
1.1 cvs 4778: END;
4779: </PRE>
4780: </BLOCKQUOTE>
4781: <BLOCKQUOTE class="example">
4782: <P>
4783: <STRONG>Example:</STRONG></P>
4784: <P>
1.3 cvs 4785: The element SectionTitle creates a presentation box called SectionNum which
4786: contains the number of the section. Suppose we want to align the SectionNum
4787: and SectionTitle horizontally, have the SectionNum take its width from its
4788: contents (the section number), have the SectionTitle box begin 0.5 cm to the
4789: right of the SectionNum box and end at the right edge of its enclosing box.
4790: This would make the SectionTitle box elastic, since its width is defined by the
4791: position of its left and right sides. The following rules produce this
1.1 cvs 4792: effect:</P>
4793: <PRE>
4794: SectionNum :
4795: BEGIN
4796: HorizPos : Left = Enclosing . Left;
4797: Width : Enclosed . Width;
4798: ...
4799: END;
4800:
4801: SectionTitle :
4802: BEGIN
4803: HorizPos : Left = SectionNum . Right + 0.5 cm;
4804: Width : Right = Enclosing . Right;
4805: ...
4806: END;
4807: </PRE>
4808: </BLOCKQUOTE>
4809: </DIV>
4810: </DIV>
4811:
4812: <DIV class="subsection">
1.6 cvs 4813: <H3><A name="sectc4220">Overflow</A></H3>
1.1 cvs 4814:
4815: <P>
4816: A boxes corresponding to a structural element normally contain all boxes
4817: corresponding to the elements of its subtree. However, in some cases, it
4818: could be necessary to allow a box to jut out from its parent box. Two
4819: presentation rules indicate that such an overflow is allowed, one for
4820: horizontal overflow, one for vertical overflow.</P>
4821: <P>
4822: Each of these rules is expressed by a keyword followed by a colon and the
4823: keyword <TT>Yes</TT> or <TT>No</TT>.</P>
4824: <PRE>
4825: 'VertOverflow' ':' Boolean /
4826: 'HorizOverflow' ':' Boolean .
4827: Boolean = 'Yes' / 'No' .
4828: </PRE>
4829: </DIV>
4830:
4831: <DIV class="subsection">
1.6 cvs 4832: <H3><A name=sectc4221>Inheritance</A></H3>
1.1 cvs 4833:
4834: <P>
4835: A presentation parameter can be defined by reference to the same parameter of
4836: another box in the tree of boxes. These structural links are expressed by
4837: kinship. The reference box can be that of the element immediately above in
4838: the structure (<TT>Enclosing</TT>), two levels above (<TT>GrandFather</TT>),
4839: immediately below (<TT>Enclosed</TT>) or immediately before
4840: (<TT>Previous</TT>). In the case of a presentation box, and only in that
4841: case, the reference box may be the element which created the presentation box
4842: (<TT>Creator</TT>).</P>
4843: <P>
4844: Kinship is expressed in terms of the logical structure of the document and not
4845: in terms of the tree of boxes. The presentation box cannot transmit any of
4846: their parameters by inheritance; only structured element boxes can do so. As
4847: an example, consider an element B which follows an element A in the logical
4848: structure. The element B creates a presentation box P in front of itself,
1.6 cvs 4849: using the <TT>CreateBefore</TT> rule (see the <A href="#sectc4232">creation
1.1 cvs 4850: rules</A>). If element B's box inherits its character style using the
4851: <TT>Previous</TT> kinship operation, it gets its character style from A's box,
4852: not from P's box. Inheritance works differently for positions and extents,
4853: which can refer to presentation boxes.</P>
4854: <P>
4855: The inherited parameter value can be the same as that of the reference box.
4856: This is indicated by an equals sign. However, for numeric parameters, a
4857: different value can be obtained by adding or subtracting a number from the
4858: reference box's parameter value. Addition is indicated by a plus sign before
4859: the number, while subtraction is specified with a minus sign. The value of a
4860: parameter can also be given a maximum (if the sign is a plus) or minimum (if
4861: the sign is a minus).</P>
4862: <P>
4863: If the rule is being applied to a numeric attribute, the number to add or
4864: subtract can be replaced by the attribute name. The value of a maximum or
4865: minimum may also be replaced by an attribute name. In these cases, the value
4866: of the attribute is used.</P>
4867: <PRE>
1.6 cvs 4868: Inheritance = Kinship InheritedValue .
4869: Kinship ='Enclosing' / 'GrandFather' / 'Enclosed' /
4870: 'Previous' / 'Creator' .
1.1 cvs 4871: InheritedValue ='+' PosIntAttr [ 'Max' maximumA ] /
1.6 cvs 4872: '-' NegIntAttr [ 'Min' minimumA ] /
4873: '=' .
4874: PosIntAttr = PosInt / AttrID .
4875: PosInt = NUMBER .
4876: NegIntAttr = NegInt / AttrID .
4877: NegInt = NUMBER .
4878: maximumA = maximum / AttrID .
4879: maximum = NUMBER .
4880: minimumA = minimum / AttrID .
4881: minimum = NUMBER .
1.1 cvs 4882: </PRE>
4883: <P>
4884: The parameters which can be obtained by inheritance are justification,
4885: hyphenation, interline spacing, character font (font family), font style, font
4886: size, visibility, indentation, underlining, alignment of text, stacking order
4887: of objects, the style and thickness of lines, fill pattern and the colors of
4888: lines and characters.</P>
4889: </DIV>
4890:
4891: <DIV class="subsection">
1.6 cvs 4892: <H3><A name=sectc4222>Line breaking</A></H3>
1.1 cvs 4893:
4894: <P>
4895: The <TT>Line</TT> rule specifies that the contents of the box should be broken
4896: into lines: the boxes included in the box to which this rule is attached are
4897: displayed one after the other, from left to right, with their horizontal
4898: reference axes aligned so that they form a series of lines. The length of
4899: these lines is equal to the width of the box to which the <TT>Line</TT> rule
4900: is attached.</P>
4901: <P>
4902: When an included box overflows the current line, it is either carried forward
4903: to the next line, cur, or left the way it is. The <A
1.6 cvs 4904: href="#sectc4223"><TT>LineBreak</TT> rule</A> is used to allow or prevent the
1.1 cvs 4905: breaking of included boxes. If the included box is not breakable but is
4906: longer than the space remaining on the line, it is left as is. When a
4907: character string box is breakable, the line is broken between words or, if
1.6 cvs 4908: necessary, by <A href="#sectd42225">hyphenating a word</A>. When a
1.1 cvs 4909: compound box is breakable, the box is transparent in regard to line breaking.
4910: The boxes included in the compound box are treated just like included boxes
4911: which have the <TT>LineBreak</TT> rule. Thus, it is possible to traverse a
4912: complete subtree of boxes to line break the text leaves of a complex
4913: structure.</P>
4914: <P>
4915: The relative position rules of the included boxes are ignored, since the boxes
4916: will be placed according to the line breaking rules.</P>
4917: <P>
4918: The <TT>Line</TT> rule does not have a parameter. The characteristics of the
4919: lines that will be constructed are determined by the <TT>LineSpacing</TT>,
4920: <TT>Indent</TT>, <TT>Adjust</TT>, <TT>Justify</TT>, and <TT>Hyphenate</TT>
1.6 cvs 4921: rules. Moreover, the <A href="#insectd42226"><TT>Inline</TT> rule</A> permits
1.1 cvs 4922: the exclusion of certain elements from the line breaking process.</P>
4923: <P>
4924: When the <TT>Line</TT> rule appears in the rules sequence of a non-primary
4925: view, it applies only to that view, but when the <TT>Line</TT> rule appears in
4926: the rules sequence of the primary view, it also applies to the other views by
4927: default, except for those views which explicitly invoke the <TT>NoLine</TT>
4928: rule. Thus, the <TT>NoLine</TT> rule can be used in a non-primary view to
4929: override the primary view's <TT>Line</TT> rule. The <TT>NoLine</TT> rule must
4930: not be used with the primary view because the absence of the <TT>Line</TT>
4931: rule has the same effect. Like the <TT>Line</TT> rule, the <TT>NoLine</TT>
4932: rule does not take any parameters.</P>
4933: <PRE>
1.6 cvs 4934: 'Line'
4935: 'NoLine'
1.1 cvs 4936: </PRE>
4937:
4938: <DIV class="subsubsection">
1.6 cvs 4939: <H4><A name=sectd42221>Line spacing</A></H4>
1.1 cvs 4940:
4941: <P>
4942: The <TT>LineSpacing</TT> rule defines the line spacing to be used in the line
4943: breaking process. The line spacing is the distance between the baselines
4944: (horizontal reference axis) of the successive lines produced by the
4945: <TT>Line</TT> rule. The value of the line spacing can be specified as a
4946: constant or by inheritance. It is expressed in any of the available <A
1.6 cvs 4947: href="#sectc4217">distance units</A>.</P>
1.1 cvs 4948: <P>
4949: Inheritance allows the value to be obtained from a relative in the structure
4950: tree, either without change (an equals sign appears after the inheritance
4951: keyword), with a positive difference (a plus sign), or a negative difference
4952: (a minus sign). When the rule uses a difference, the value of the difference
1.6 cvs 4953: follows the sign and is expressed as a <A href="#sectc4217">distance</A>.</P>
1.1 cvs 4954: <PRE>
1.6 cvs 4955: 'LineSpacing' ':' DistOrInherit
4956: DistOrInherit = Kinship InheritedDist / Distance .
1.1 cvs 4957: InheritedDist = '=' / '+' AbsDist / '-' AbsDist .
4958: </PRE>
4959: <P>
4960: When the line spacing value (or its difference from another element) is
4961: expressed in relative units, it changes with the size of the characters. Thus,
4962: when a larger font is chosen for a part of the document, the line spacing of
4963: that part expands proportionally. In contrast, when the line spacing value is
4964: expressed in absolute units (centimeters, inches, typographer's points), it is
4965: independent of the characters, which permits the maintenance of a consistent
4966: line spacing, whatever the character font. Either approach can be taken,
4967: depending on the desired effect.</P>
4968: </DIV>
4969:
4970: <DIV class="subsubsection">
1.6 cvs 4971: <H4><A name=sectd42222>First line indentation</A></H4>
1.1 cvs 4972:
4973: <P>
4974: The <TT>Indent</TT> rule is used to specify the indentation of the first line
4975: of the elements broken into lines by the <TT>Line</TT> function. The
4976: indentation determines how far the first line of the element is shifted with
4977: respect to the other lines of the same element. It can be specified as a
4978: constant or by inheritance. The constant value is a positive integer (shifted
4979: to the right; the sign is optional), a negative integer (shifted to the left)
1.6 cvs 4980: or zero (no shift). All available <A href="#sectc4217">units</A> can be
1.1 cvs 4981: used.</P>
4982: <P>
4983: Indentation can be defined for any box, regardless of whether the box is line
4984: broken, and transmitted by inheritance to elements that are line broken. The
4985: size of the indentation is specified in the same manner as the <A
1.6 cvs 4986: href="#sectd42221">line spacing</A>.</P>
1.1 cvs 4987: <PRE>
1.6 cvs 4988: 'Indent' ':' DistOrInherit
1.1 cvs 4989: </PRE>
4990: </DIV>
4991:
4992: <DIV class="subsubsection">
1.6 cvs 4993: <H4><A name=sectd42223>Alignment</A></H4>
1.1 cvs 4994:
4995: <P>
4996: The alignment style of the lines constructed during line breaking is defined
4997: by the <TT>Adjust</TT> rule. The alignment value can be a constant or
4998: inherited. A constant value is specified by a keyword:</P>
4999: <UL>
5000: <LI><TT>Left</TT>: at the left edge,
5001: <LI><TT>Right</TT>: at the right edge,
5002: <LI><TT>VMiddle</TT>: centered
1.2 cvs 5003: <LI><TT>LeftWithDots</TT>: at the left edge with a dotted line filling out the
1.1 cvs 5004: last line up to the right edge of the line breaking box.
5005: </UL>
5006: <P>
5007: An inherited value can only be the same as that of the reference box and is
5008: specified by a kinship keyword followed by an equals sign.</P>
5009: <PRE>
1.6 cvs 5010: 'Adjust' ':' AlignOrInherit
1.1 cvs 5011: AlignOrInherit = Kinship '=' / Alignment .
5012: Alignment = 'Left' / 'Right' / 'VMiddle' /
5013: 'LeftWithDots' .
5014: </PRE>
5015: </DIV>
5016:
5017: <DIV class="subsubsection">
1.6 cvs 5018: <H4><A name=sectd42224>Justification</A></H4>
1.1 cvs 5019:
5020: <P>
5021: The <TT>Justify</TT> rule indicates whether the lines contained in the box and
5022: produced by a <TT>Line</TT> rule should be extended horizontally to occupy the
5023: entire width of their enclosing box. The first and last lines are treated
5024: specially: the position of the beginning of the first line is fixed by the
5025: <TT>Indent</TT> rule and last line is not extended. The justification
5026: parameter defined by this rule takes a boolean value, which can be a constant
5027: or inherited. A constant boolean value is expressed by either the
5028: <TT>Yes</TT> or the <TT>No</TT> keyword. An inherited value can only be the
5029: same as that of the reference box and is specified by a kinship keyword
5030: followed by an equals sign.</P>
5031: <PRE>
1.6 cvs 5032: 'Justify' ':' BoolInherit
1.1 cvs 5033: BoolInherit = Boolean / Kinship '=' .
1.6 cvs 5034: Boolean ='Yes' / 'No' .
1.1 cvs 5035: </PRE>
5036: <P>
5037: When the lines are justified, the alignment parameter specified in the
5038: <TT>Adjust</TT> rule has no influence, other than on the last line produced.
5039: This occurs because, when the other are extended to the limits of the box, the
5040: alignment style is no longer perceptible.</P>
5041: <BLOCKQUOTE class="example">
5042: <P>
5043: <STRONG>Example:</STRONG></P>
5044: <P>
1.3 cvs 5045: An important use of inheritance is to vary the characteristics of lines for an
5046: element type (for example, Paragraph) according to the enclosing environment
5047: (for example, Summary or Section), and thus obtain different line breaking
5048: styles for the same elements when they appear in different environments. The
5049: following rules specify that paragraphs inherit their alignment, justification,
1.1 cvs 5050: and line spacing:</P>
5051: <PRE>
5052: Paragraph :
5053: BEGIN
5054: Justify : Enclosing = ;
5055: LineSpacing : Enclosing = ;
5056: Adjust : Enclosing =;
5057: Line;
5058: END;
5059: </PRE>
5060: <P>
1.5 cvs 5061: If the alignment, justification, and line spacing of the Section and Summary
1.1 cvs 5062: elements is fixed:</P>
5063: <PRE>
5064: Section :
5065: BEGIN
5066: Adjust : Left;
5067: Justify : Yes;
5068: LineSpacing : 1;
5069: END;
5070: Summary :
5071: BEGIN
5072: Adjust : VMiddle;
5073: Justify : No;
5074: LineSpacing : 1.3;
5075: END;
5076: </PRE>
5077: <P>
1.4 cvs 5078: then the paragraphs appearing in sections are justified with a simple line
5079: spacing while those appearing in summaries are centered and not justified and
5080: have a larger line spacing. These are nevertheless the very same type of
1.1 cvs 5081: paragraph defined in the logical structure schema.</P>
5082: </BLOCKQUOTE>
5083: </DIV>
5084:
5085: <DIV class="subsubsection">
1.6 cvs 5086: <H4><A name=sectd42225>Hyphenation</A></H4>
1.1 cvs 5087:
5088: <P>
5089: The <TT>Hyphenate</TT> rule indicates whether or not words should be broken by
5090: hyphenation at the end of lines. It affects the lines produced by the
5091: <TT>Line</TT> rule and contained in the box carrying the <TT>Hyphenate</TT>
5092: rule.</P>
5093: <P>
5094: The hyphenation parameter takes a boolean value, which can be either constant
5095: or inherited. A constant boolean value is expressed by either the
5096: <TT>Yes</TT> or the <TT>No</TT> keyword. An inherited value can only be the
5097: same as that of the reference box and is specified by a kinship keyword
5098: followed by an equals sign.</P>
5099: <PRE>
5100: 'Hyphenate' ':' BoolInherit
5101: BoolInherit = Boolean / Kinship '=' .
5102: Boolean = 'Yes' / 'No' .
5103: </PRE>
5104: </DIV>
5105:
5106: <DIV class="subsubsection">
1.6 cvs 5107: <H4><A name=sectd42226>Avoiding line breaking</A></H4>
1.1 cvs 5108:
5109: <P>
5110: The <TT>InLine</TT> rule is used to specify that a box that would otherwise
5111: participate in line breaking asked for by the <TT>Line</TT> rule of an
5112: enclosing box, instead avoids the line breaking process and positions itself
5113: according to the <TT>HorizPos</TT> and <TT>VertPos</TT> rules that apply to
5114: it. When the <TT>InLine</TT> rule applies to a box which would not be line
5115: broken, it has no effect.</P>
5116: <P>
5117: The rule is expressed by the <TT>InLine</TT> keyword followed by a colon and
5118: the keyword <TT>Yes</TT>, if the box should participate in line breaking, or
5119: the keyword <TT>No</TT>, if it should not. This is the only form possible:
5120: this rule cannot be inherited. Moreover, it can only appear in the rules of
5121: the primary view and applies to all views defined in the presentation
5122: schema.</P>
5123: <PRE>
5124: 'InLine' ':' Boolean .
5125: Boolean = 'Yes' / 'No' .
5126: </PRE>
5127: <BLOCKQUOTE class="example">
5128: <P>
5129: <STRONG>Example:</STRONG></P>
5130: <P>
5131: Suppose the structure schema defines a logical attribute
1.3 cvs 5132: called <TT>New</TT> which is used to identify the passages in a document which
1.5 cvs 5133: were recently modified. It would be nice to have the presentation schema make
5134: a bar appear in the left margin next to each passage having
1.3 cvs 5135: the <TT>New</TT> attribute. A new passage can be an entire element, such as a
5136: paragraph or section, or it can be some words in the middle of a paragraph. To
5137: produce the desired effect, the <TT>New</TT> attribute is given a creation rule
5138: which generates a <TT>VerticalBar</TT> presentation box.</P>
1.1 cvs 5139: <P>
5140: When the <TT>New</TT> attribute is attached to a character string which is
5141: inside a line broken element (inside a paragraph, for example), the bar is one
5142: of the elements which participates in line breaking and it is placed normally
5143: in the current line, at the end of the character string which has the
5144: attribute. To avoid this, the <TT>InLine</TT> rule is used in the following
5145: way:</P>
5146: <PRE>
5147: BOXES
5148: VerticalBar:
5149: BEGIN
5150: Content: Graphics 'l';
5151: HorizPos: Left = Root . Left;
5152: VertPos: Top = Creator . Top;
5153: Height: Bottom = Creator . Bottom;
5154: Width: 1 pt;
5155: InLine: No;
5156: ...
5157: END;
5158: ...
5159: ATTRIBUTES
5160: Nouveau:
5161: BEGIN
5162: CreateAfter(VerticalBar);
5163: END;
5164: </PRE>
5165: </BLOCKQUOTE>
5166: </DIV>
5167: </DIV>
5168:
5169: <DIV class="subsection">
1.6 cvs 5170: <H3><A name=sectc4223>Page breaking and line breaking conditions</A></H3>
1.1 cvs 5171:
5172: <P>
5173: Pages are constructed by the editor in accordance with the model specified by
1.6 cvs 5174: a <A href="#sectc4233"><TT>Page</TT> rule</A>. The page model describes only the
1.1 cvs 5175: composition of the pages but does not give any rules for breaking different
5176: element types across pages. Now, it is possible that certain elements must
5177: not be cut by page breaks, while others can be cut anywhere. The
5178: <TT>PageBreak</TT>, <TT>NoBreak1</TT>, and <TT>NoBreak2</TT> rules are used to
5179: specify the conditions under which each element type can be cut.</P>
5180: <P>
5181: The <TT>PageBreak</TT> rule is used to indicate whether or not the box can be
5182: cut during the construction of pages. If cutting is authorized, the box can
5183: be cut, with one part appearing at the bottom of a page and the other part
5184: appearing at the top of the next page. The rule is formed by the
5185: <TT>PageBreak</TT> keyword followed by a colon and a constant boolean value
5186: (<TT>Yes</TT> or <TT>No</TT>). This is the only form possible: this rule
5187: cannot be inherited. Moreover, it can only appear in the rules of the primary
5188: view and applies to all views defined in the presentation schema.</P>
5189: <P>
5190: Whether objects can be cut by line breaks can be controlled in a similar way
5191: using the <TT>LineBreak</TT> rule. This rule allows the specification of
5192: whether or not the box can be cut during the construction of lines. If
5193: cutting is authorized, the box can be cut, with one part appearing at the end
5194: of a line and the other part appearing at the beginning of the next line. The
5195: rule is formed by the <TT>LineBreak</TT> keyword followed by a colon and a
5196: constant boolean value (<TT>Yes</TT> or <TT>No</TT>). This is the only form
5197: possible: this rule cannot be inherited. Moreover, it can only appear in the
5198: rules of the primary view and applies to all views defined in the presentation
5199: schema.</P>
5200: <PRE>
5201: 'PageBreak' ':' Boolean .
5202: 'LineBreak' ':' Boolean .
5203: Boolean = 'Yes' / 'No' .
5204: </PRE>
5205: <P>
5206: When a box can be cut by a page break, it is possible that a page break will
5207: fall an inappropriate spot, creating, for example, a widow or orphan, or
5208: separating the title of a section from the first paragraph of the section. The
5209: <TT>NoBreak1</TT> and <TT>NoBreak2</TT> rules are used to avoid this. They
1.12 ! cvs 5210: specify that the box of the element to which they apply cannot be cut within
! 5211: a certain zone at the top (<TT>NoBreak1</TT> rule) or at the bottom
1.1 cvs 5212: (<TT>NoBreak2</TT> rule). These two rules specify the height of the zones in
5213: which page breaks are prohibited.</P>
5214: <P>
5215: The <TT>NoBreak1</TT> and <TT>NoBreak2</TT> rules give the height of the zone
5216: in which page breaking is prohibited. The height is given as a constant value
1.6 cvs 5217: using any of the <A href="#sectc4217">available units</A>, absolute or
1.1 cvs 5218: relative. The value may not be inherited.</P>
5219: <PRE>
5220: 'NoBreak1' ':' AbsDist .
5221: 'NoBreak2' ':' AbsDist .
5222: </PRE>
5223: <BLOCKQUOTE class="example">
5224: <P>
5225: <STRONG>Example:</STRONG></P>
5226: <P>
1.3 cvs 5227: The following rules prevent widows and orphans in a paragraph:</P>
1.1 cvs 5228: <PRE>
5229: Paragraph :
5230: BEGIN
5231: NoBreak1 : 2;
5232: NoBreak2 : 2;
5233: END;
5234: </PRE>
5235: <P>
1.3 cvs 5236: This rule prevents a section title from becoming separated from the first
5237: paragraph of the section by prohibiting page breaks at the beginning of the
1.1 cvs 5238: section rule:</P>
5239: <PRE>
5240: Section :
5241: NoBreak1 : 1.5 cm;
5242: </PRE>
5243: <P>
5244: Finally, this rule prevents a figure from being page broken in any way:</P>
5245: <PRE>
5246: Figure :
5247: PageBreak : No;
5248: </PRE>
5249: </BLOCKQUOTE>
5250: <P>
5251: The Thot editor constructs the document images displayed on the screen
5252: dynamically. As the user moves in the document or makes the document scroll
5253: in a window, the editor constructs the image to be displayed in little bits,
5254: filling the gaps which are produced in the course of these operations. It
5255: stops filling in the image when an element reaches the edge of the window in
5256: which the gap appears. If the appearance of the document is complex, it is
5257: possible that the image in incomplete, even though the edge of the window was
5258: reached. For example, an element might need to be presented to the side of
5259: the last element displayed, but its image was not constructed. The user will
5260: not know whether the element is really absent or if its image has simply not
5261: been constructed.</P>
5262: <P>
5263: The <TT>Gather</TT> rule is used to remedy this problem. When the rule
5264: <TT>Gather : Yes;</TT> is associated with an element type, the image of such
5265: elements is constructed as a block by the editor: it is never split up.</P>
5266: <P>
5267: The <TT>Gather</TT> rule may not appear in the <A
1.6 cvs 5268: href="#sectc427">default rules</A>. Elements which do not have the
1.1 cvs 5269: <TT>Gather</TT> rule are considered susceptible to being split up during
5270: display. Thus, it is not necessary to use the <TT>Gather : No;</TT> form.
5271: This rule must be used prudently and only for those elements which truly need
5272: it. If used incorrectly, it can pointlessly increase the size of the image
5273: constructed by the editor and lead to excessive memory consumption by the
5274: editor.</P>
5275: <P>
5276: Like the <TT>PageBreak</TT> and <TT>LineBreak</TT> rules, the <TT>Gather</TT>
5277: rule can only appear in rules of the primary view and applies to all views
5278: defined in the presentation schema.</P>
5279: <PRE>
5280: 'Gather' ':' Boolean .
5281: </PRE>
5282: </DIV>
5283:
5284: <DIV class="subsection">
1.6 cvs 5285: <H3><A name=sectc4224>Visibility</A></H3>
1.1 cvs 5286:
5287: <P>
5288: The visibility parameter is used to control which elements should or should
5289: not be displayed, based on context. An element can have different
5290: visibilities in different views. If an element's visibility is zero for a
5291: view, that element is not displayed in that view and does not occupy any space
5292: (its extents are zero).</P>
5293: <P>
5294: Visibility takes non-negative integer values (positive or zero). If values
5295: greater than 1 are used, they allow the user to choose a degree of visibility
5296: and, thus, to see only those boxes whose visibility parameter exceeds a
5297: certain threshold. This gives the user control over the granularity of the
1.2 cvs 5298: displayed pictures.</P>
1.1 cvs 5299: <P>
5300: The visibility parameter can be defined as a constant or by inheritance. If
5301: defined by inheritance, it cannot be based on the value of the next or
5302: previous box. Visibility can only be inherited from above.</P>
5303: <P>
5304: If it is a numeric attribute's presentation rule, the visibility can be
5305: specified by the attribute's name, in which case the value of the attribute is
5306: used.</P>
5307: <PRE>
1.6 cvs 5308: 'Visibility' ':' NumberInherit
1.1 cvs 5309: NumberInherit = Integer / AttrID / Inheritance .
1.6 cvs 5310: Integer = NUMBER .
1.1 cvs 5311: </PRE>
5312: <BLOCKQUOTE class="example">
5313: <P>
5314: <STRONG>Example:</STRONG></P>
5315: <P>
1.3 cvs 5316: Suppose that only <TT>Formula</TT> elements should be displayed in
5317: the <TT>MathView</TT> view. Then, the default rules should include:</P>
1.1 cvs 5318: <PRE>
5319: DEFAULT
5320: IN MathView Visibility:0;
5321: </PRE>
5322: <P>
1.3 cvs 5323: which makes all elements invisible in the <TT>MathView</TT> view. However, the
5324: <TT>Formula</TT> element also has a <TT>Visibility</TT> rule:</P>
1.1 cvs 5325: <PRE>
5326: Formula :
5327: IN MathView Visibility:5;
5328: </PRE>
5329: <P>
5330: which makes formulas, and only formulas, visible.</P>
5331: </BLOCKQUOTE>
5332: </DIV>
5333:
5334: <DIV class="subsection">
1.6 cvs 5335: <H3><A name=sectc4225>Character style parameters</A></H3>
1.1 cvs 5336:
5337: <P>
5338: Four parameters are used to determine which characters are used to display
5339: text. They are size, font, style, and underlining.</P>
5340:
5341: <DIV class="subsubsection">
1.6 cvs 5342: <H4><A name=sectd42251>Character size</A></H4>
1.1 cvs 5343:
5344: <P>
5345: The size parameter has two effects. First, it is used to specify the actual
1.6 cvs 5346: size and distance units for boxes defined in <A href="#sectc4217">relative
1.1 cvs 5347: units</A>. Second, it defines the size of the characters contained in the
5348: box.</P>
5349: <P>
5350: As a distance or length, the size can be expressed in abstract or absolute
5351: units. It can also be inherited. If it is not inherited, it is expressed
5352: simply as an integer followed by the <TT>pt</TT> keyword, which indicates that
5353: the size is expressed in typographer's points. The absence of the <TT>pt</TT>
5354: keyword indicates that it is in abstract units in which the value 1 represents
5355: the smallest size while the value 16 is the largest size. The relationship
5356: between these abstract sizes and the real character sizes is controlled by a
5357: table which can be modified statically or even dynamically during the
5358: execution of the Thot editor.</P>
5359: <P>
5360: If it is a numeric attribute's presentation rule, the value of the size
5361: parameter can be specified by the attribute's name, in which case the value of
5362: the attribute is used.</P>
5363: <P>
5364: <STRONG>Note:</STRONG> the only unit available for defining an absolute size
5365: is the typographer's point. Centimeters and inches may not be used.</P>
5366: <P>
5367: If the size is inherited, the rule must specify the relative from which to
5368: inherit and any difference from that relative's value. The difference can be
5369: expressed in either typographer's points or in abstract units. The maximum or
5370: minimum size can also be specified, but without specifying the type of unit:
5371: it is the same as was specified for the difference.</P>
5372: <P>
5373: In a numeric attribute's presentation rule, the difference in size can be
5374: indicated by the attribute's name, which means that the attribute's value
5375: should be used as the difference. The attribute can also be used as the
5376: minimum or maximum size.</P>
5377: <PRE>
5378: 'Size' ':' SizeInherit
5379: SizeInherit = SizeAttr [ 'pt' ] /
5380: Kinship InheritedSize .
5381: InheritedSize ='+' SizeAttr [ 'pt' ]
5382: [ 'Max' MaxSizeAttr ] /
5383: '-' SizeAttr [ 'pt' ]
5384: [ 'Min' MinSizeAttr ] /
5385: '=' .
1.6 cvs 5386: SizeAttr = Size / AttrID .
5387: Size = NUMBER .
5388: MaxSizeAttr = MaxSize / AttrID .
5389: MaxSize = NUMBER .
5390: MinSizeAttr = MinSize / AttrID .
5391: MinSize = NUMBER .
1.1 cvs 5392: </PRE>
5393: <BLOCKQUOTE class="example">
5394: <P>
5395: <STRONG>Example:</STRONG></P>
5396: <P>
5397: The rule</P>
5398: <PRE>
5399: Size : Enclosing - 2 pt Min 7;
5400: </PRE>
5401: <P>
1.3 cvs 5402: states that the character size is 2 points less than that of the enclosing box,
5403: but that it may not be less than 7 points, whatever the enclosing box's
1.1 cvs 5404: value.</P>
5405: <P>
5406: The following rules make the text of a report be displayed with medium-sized
5407: characters (for example, size 5), while the title is displayed with larger
5408: characters and the summary is displayed with smaller characters:</P>
5409: <PRE>
5410: Report :
5411: Size : 5;
5412: Title :
5413: Size : Enclosing + 2;
5414: Summary :
5415: Size : Enclosing - 1;
5416: </PRE>
5417: <P>
1.4 cvs 5418: Thus, the character sizes in the entire document can be changed by changing the
5419: size parameter of the Report element, while preserving the relationships
1.1 cvs 5420: between the sizes of the different elements.</P>
5421: </BLOCKQUOTE>
5422: </DIV>
5423:
5424: <DIV class="subsubsection">
1.6 cvs 5425: <H4><A name=sectd42252>Font and character style</A></H4>
1.1 cvs 5426:
5427: <P>
5428: The <TT>Font</TT> rule determines the font family to be used to display the
5429: characters contained in the box, while the <TT>Style</TT> rule determines
5430: their style. Thot recognizes three character fonts (Times, Helvetica, and
5431: Courier) and six styles: Roman, Italics, Bold, BoldItalics, Oblique, and
5432: BoldOblique.</P>
5433: <P>
5434: The font family and style can specified by a named constant or can be
5435: inherited. For the name of the font family only the first character is
5436: used.</P>
5437: <P>
5438: Only identical inheritance is allowed: the box takes the same font or style as
5439: the box from which it inherits. This is indicated by an equals sign after the
5440: kinship specification.</P>
5441: <BLOCKQUOTE class="example">
5442: <P>
5443: <STRONG>Example:</STRONG></P>
5444: <P>
1.3 cvs 5445: To specify that the summary uses the font family of the rest of the document,
1.1 cvs 5446: but in the italic style, the following rules are used:</P>
5447: <PRE>
5448: Summary :
5449: BEGIN
5450: Font : Enclosing =;
5451: Style : Italics;
5452: END;
5453: </PRE>
5454: </BLOCKQUOTE>
5455: </DIV>
5456:
5457: <DIV class="subsubsection">
1.6 cvs 5458: <H4><A name=sectd42253>Underlining</A></H4>
1.1 cvs 5459:
5460: <P>
5461: The <TT>Underline</TT> rule is used to specify if the characters contained in
5462: a box should have lines drawn on or near them. There are four underlining
5463: styles: <TT>Underlined</TT>, <TT>Overlined</TT>, <TT>CrossedOut</TT>, and
5464: <TT>NoUnderline</TT>. The <TT>Thickness</TT> rule specifies the thickness of
5465: the line, <TT>Thin</TT> or <TT>Thick</TT>.</P>
5466: <P>
5467: As with font family and style, only identical inheritance is allowed: the box
5468: has the same underlining type as the box from which it inherits the value.
5469: This is indicated by an equals sign after the kinship specification.</P>
5470: <PRE>
5471: 'Underline' ':' UnderLineInherit /
5472: 'Thickness' ':' ThicknessInherit /
5473:
5474: UnderLineInherit = Kinship '=' / 'NoUnderline' /
5475: 'Underlined' /
5476: 'Overlined' / 'CrossedOut' .
5477: ThicknessInherit = Kinship '=' / 'Thick' / 'Thin' .
5478: </PRE>
5479: </DIV>
5480: </DIV>
5481:
5482: <DIV class="subsection">
1.6 cvs 5483: <H3><A name=sectc4226>Stacking order</A></H3>
1.1 cvs 5484:
5485: <P>
5486: The <TT>Depth</TT> rule is used to define the stacking order of terminal boxes
5487: when multiple boxes at least partially overlap. This rule defines how the
5488: depth parameter, which is zero or a positive integer, is calculated. The
5489: depth parameter has a value for all boxes. For terminal boxes in the
5490: structure and for presentation boxes, the depth value is used during display
5491: and printing: the boxes with the lowest value overlap those with higher
5492: depths. For non-terminal boxes, the depth is not interpreted during display,
5493: but it is used to calculate the depth of terminal boxes by inheritance.</P>
5494: <P>
5495: Like most other rules, the depth rule is defined in the <A
1.6 cvs 5496: href="#sectc427">default rules</A> of each presentation schema. Thus,
1.1 cvs 5497: there is always a depth value, even when it is not necessary because there is
5498: no overlapping. To avoid useless operations, a zero value can be given to the
5499: depth parameter, which signifies that overlapping is never a problem.</P>
5500: <P>
1.6 cvs 5501: The depth rule has the same form as the <A href="#sectc4224">visibility rule</A>.
1.1 cvs 5502: It can be defined by inheritance or by a constant numeric value. When the rule
5503: is attached to a numeric attribute, it can take the value of that
5504: attribute.</P>
5505: <PRE>
5506: 'Depth' ':' NumberInherit
5507: </PRE>
5508: <BLOCKQUOTE class="example">
5509: <P>
5510: <STRONG>Example:</STRONG></P>
5511: <P>
1.3 cvs 5512: For a purely textual document, in which overlapping never poses a problem, a
1.5 cvs 5513: single default <TT>Depth</TT> rule in the presentation schema is
5514: sufficient:</P>
1.1 cvs 5515: <PRE>
5516: DEFAULT
5517: Depth : 0;
5518: ...
5519: </PRE>
5520: <P>
5521: To make the text of examples appear on a light blue background, a presentation
5522: box is defined:</P>
5523: <PRE>
5524: BOXES
5525: BlueBG :
5526: BEGIN
5527: Content : Graphics 'R';
5528: Background : LightBlue3;
5529: FillPattern: backgroundcolor;
5530: Depth : 2;
5531: ...
5532: END;
5533: </PRE>
5534: <P>
1.3 cvs 5535: and is created by the <TT>Example</TT> element, which has the rules:</P>
1.1 cvs 5536: <PRE>
5537: RULES
5538: Example :
5539: BEGIN
5540: CreateFirst (BlueBG);
5541: Depth : 1;
5542: ...
5543: END;
5544: </PRE>
5545: <P>
5546: In this way, the text of an example (if it inherits its depth from
1.5 cvs 5547: its ancestor) will be superimposed on a light blue background, and not
5548: the reverse).</P>
1.1 cvs 5549: </BLOCKQUOTE>
5550: </DIV>
5551:
5552: <DIV class="subsection">
1.6 cvs 5553: <H3><A name=sectc4227>Line Style</A></H3>
1.1 cvs 5554:
5555: <P>
5556: The <TT>LineStyle</TT> rule determines the style of line which should be used
5557: to draw all the elements contained in the box. The line style can be
5558: indicated by a name (<TT>Solid</TT>, <TT>Dashed</TT>, <TT>Dotted</TT>) or it
5559: can be inherited. Only elements of the graphic base type are affected by this
5560: rule, but it can be attached to any box and transmitted by inheritance to the
5561: graphic elements.</P>
5562: <P>
5563: Only identical inheritance is allowed: the box takes the same line style as
5564: the box from which it inherits. This is indicated by an equals sign after the
5565: kinship specification.</P>
5566: <PRE>
5567: 'LineStyle' ':' LineStyleInherit
5568: LineStyleInherit = Kinship '=' /
5569: 'Solid' / 'Dashed' / 'Dotted' .
5570: </PRE>
5571: <BLOCKQUOTE class="example">
5572: <P>
5573: <STRONG>Example:</STRONG></P>
5574: <P>
1.3 cvs 5575: To specify that, in Figures, the graphical parts should be drawn in solid
5576: lines, the Figure element is given a rule using the <TT>Solid</TT> name:</P>
1.1 cvs 5577: <PRE>
5578: Figure :
5579: LineStyle : Solid;
5580: </PRE>
5581: <P>
5582: and the elements composing figures are given an inheritance rule:</P>
5583: <PRE>
5584: LineStyle : Enclosing =;
5585: </PRE>
5586: </BLOCKQUOTE>
5587: </DIV>
5588:
5589: <DIV class="subsection">
1.6 cvs 5590: <H3><A name=sectc4228>Line thickness</A></H3>
1.1 cvs 5591:
5592: <P>
5593: The <TT>LineWeight</TT> rule determines the thickness of the lines of all
5594: graphical elements which appear in the box, no matter what their line style.
5595: Line thickness can be specified by a constant value or by inheritance. A
5596: constant value is a positive number followed by an optional unit specification
5597: (which is absent when using relative units). All available <A
1.6 cvs 5598: href="#sectc4217">distance units</A> can be used. Line thickness is expressed
5599: in the same way as <A href="#sectd42221">line spacing</A>.</P>
1.1 cvs 5600: <PRE>
5601: 'LineWeight' ':' DistOrInherit
5602: </PRE>
5603: <P>
5604: Only elements of the graphic base type are affected by this rule, but it can
5605: be attached to any box and transmitted by inheritance to the graphic
5606: elements.</P>
5607: <BLOCKQUOTE class="example">
5608: <P>
5609: <STRONG>Example:</STRONG></P>
5610: <P>
1.3 cvs 5611: To specify that, in Figures, the graphical parts should be drawn with lines 0.3
1.1 cvs 5612: pt thick, the Figure element is given this rule:</P>
5613: <PRE>
5614: Figure :
5615: LineWeight : 0.3 pt;
5616: </PRE>
5617: <P>
5618: and the elements composing figures are given an inheritance rule:</P>
5619: <PRE>
5620: LineWeight : Enclosing =;
5621: </PRE>
5622: </BLOCKQUOTE>
5623: </DIV>
5624:
5625: <DIV class="subsection">
1.6 cvs 5626: <H3><A name=sectc4229>Fill pattern</A></H3>
1.1 cvs 5627:
5628: <P>
5629: The <TT>FillPattern</TT> rule determines the pattern used to fill closed
5630: graphical elements (circles, rectangles, etc.) which appear in the box. This
5631: pattern can be indicated by a named constant or by inheritance. The named
5632: constant identifies one of the patterns available in Thot. The names of the
5633: available patterns are: nopattern, foregroundcolor, backgroundcolor, gray1,
5634: gray2, gray3, gray4, gray5, gray6, gray7, horiz1, horiz2, horiz3, vert1,
5635: vert2, vert3, left1, left2, left3, right1, right2, right3, square1, square2,
5636: square3, lozenge, brick, tile, sea, basket.</P>
5637: <P>
5638: Like the other rules peculiar to graphics, <TT>LineStyle</TT> and
5639: <TT>LineWeight</TT>, only elements of the graphic base type are affected by
5640: the <TT>FillPattern</TT> rule, but the rule can be attached to any box and
5641: transmitted by inheritance to the graphic elements. As with the other rules
5642: specific to graphics, only identical inheritance is allowed.</P>
5643: <P>
5644: The <TT>FillPattern</TT> rule can also be used to determine whether or not
1.12 ! cvs 5645: text characters, symbols and pictures should be colored. For these element
! 5646: types (text, symbols, and pictures), the only valid values are
! 5647: <TT>nopattern</TT>, <TT>foregroundcolor</TT>, and
! 5648: <TT>backgroundcolor</TT>. When <TT>FillPattern</TT> has the value
1.1 cvs 5649: <TT>backgroundcolor</TT>, text characters, symbols, and bitmaps are given the
1.6 cvs 5650: color specified by the <A href="#sectc4230"><TT>Background</TT> rule</A> which
1.1 cvs 5651: applies to these elements. When <TT>FillPattern</TT> has the value
5652: <TT>foregroundcolor</TT>, these same elements are given the color specified by
1.6 cvs 5653: the <A href="#sectc4230"><TT>Foreground</TT> rule</A> which applies to these
1.1 cvs 5654: elements. In all other case, text characters are not colored.</P>
5655: <PRE>
5656: 'FillPattern' ':' NameInherit
5657: </PRE>
5658: <BLOCKQUOTE class="example">
5659: <P>
5660: <STRONG>Example:</STRONG></P>
5661: <P>
1.3 cvs 5662: To specify that, in Figures, the closed graphical elements should be filled
5663: with a pattern resembling a brick wall, the Figure element is given this
1.1 cvs 5664: rule:</P>
5665: <PRE>
5666: Figure :
5667: FillPattern : brick;
5668: </PRE>
5669: <P>
5670: and the elements composing figures are given an inheritance rule:</P>
5671: <PRE>
5672: FillPattern : Enclosing =;
5673: </PRE>
5674: </BLOCKQUOTE>
5675: </DIV>
5676:
5677: <DIV class="subsection">
1.6 cvs 5678: <H3><A name=sectc4230>Colors</A></H3>
1.1 cvs 5679:
5680: <P>
5681: The <TT>Foreground</TT> and <TT>Background</TT> rules determine the foreground
5682: and background colors of the base elements which appear in the box. These
5683: colors cancan be specified with a named constant or by inheritance. The named
5684: constants specify one of the available colors in Thot. The available color
5685: names can be found in the file <TT>thot.color</TT>.</P>
5686: <P>
5687: In contrast to the preceding rules, the color rules affect all base elements
1.2 cvs 5688: the same way, no matter what their type (text, graphics, pictures, symbols),
5689: but they only affect base elements. The color rules can nevertheless be
1.1 cvs 5690: associated with any box and can be transmitted to the base elements by
5691: inheritance. Like the preceding rules, only inheritance of the same value is
5692: allowed.</P>
5693: <PRE>
5694: 'Foreground' ':' NameInherit
5695: 'Background' ':' NameInherit
5696: </PRE>
5697: <P>
5698: <STRONG>Note:</STRONG> text colors only appear for text elements whose <A
1.6 cvs 5699: href="#sectc4229">fill pattern</A> does not prevent the use of color.</P>
1.1 cvs 5700: <BLOCKQUOTE class="example">
5701: <P>
5702: <STRONG>Example:</STRONG></P>
5703: <P>
1.3 cvs 5704: To specify that, in Figures, everything must be drawn in blue on a background
1.5 cvs 5705: of yellow, the Figure element is given these rules:</P>
1.1 cvs 5706: <PRE>
5707: Figure :
5708: BEGIN
5709: Foreground : Blue;
5710: Background : Yellow;
5711: Fillpattern : backgroundcolor;
5712: END;
5713: </PRE>
5714: <P>
5715: and the elements composing figures are given inheritance rules:</P>
5716: <PRE>
5717: Foreground : Enclosing =;
5718: Background : Enclosing =;
5719: FillPattern : Enclosing =;
5720: </PRE>
5721: </BLOCKQUOTE>
5722: </DIV>
5723:
5724: <DIV class="subsection">
1.6 cvs 5725: <H3><A name=sectc4231>Presentation box content</A></H3>
1.1 cvs 5726:
5727: <P>
5728: The <TT>Content</TT> rule applies to presentation boxes. It indicates the
5729: content given to a box. This content is either a variable's value or a
1.6 cvs 5730: constant value. In the special case of <A href="#sectc4233">header or footer
1.1 cvs 5731: boxes</A>, the content can also be a structured element type.</P>
5732: <P>
5733: If the content is a constant, it can be specified, as in a variable
5734: declaration, either by the name of a constant declared in the <TT>CONST</TT>
5735: section or by direct specification of the type and value of the box's
5736: content.</P>
5737: <P>
5738: Similarly, if it is a variable, the name of a variable declared in
5739: <TT>VAR</TT> section can be given or the variable may be defined within
5740: parentheses. The content inside the parentheses has the same syntax as a <A
1.6 cvs 5741: href="#sectc426">variable declaration</A>.</P>
1.1 cvs 5742: <P>
5743: When the content is a structured element type, the name of the element type is
5744: given after the colon. In this case, the box's content is all elements of
5745: the named type which are designated by references which are part of the page
5746: on which the header or footer with this <TT>Content</TT> rule appears. Only
5747: associated elements can appear in a <TT>Content</TT> rule and the structure
5748: must provide references to these elements. Moreover, the box whose content
5749: they are must be a header or footer box generated by a page box of the primary
5750: view.</P>
5751: <PRE>
5752: 'Content' ':' VarConst
5753: VarConst = ConstID / ConstType ConstValue /
5754: VarID / '(' FunctionSeq ')' /
5755: ElemID .
5756: </PRE>
5757: <P>
5758: A presentation box can have only one <TT>Content</TT> rule, which means that
5759: the content of a presentation box cannot vary from view to view. However, such
5760: an effect can be achieved by creating several presentation boxes, each with
5761: different content and visible in different views.</P>
5762: <P>
5763: The <TT>Content</TT> rule also applies to elements defined as references in
5764: the structure schema. In this case, the content defined by the rule must be
5765: a constant. It is this content which appears on the screen or paper to
5766: represent references of the type to which the rule applies. A reference can
1.6 cvs 5767: have a <TT>Content</TT> rule or a <A href="#sectc4234"><TT>Copy</TT> rule</A>
1.1 cvs 5768: for each view. If neither of these rules appears, the reference is displayed
5769: as <TT>[*]</TT>, which is equivalent to the rule:</P>
5770: <PRE>
5771: Content: Text '[*]';
5772: </PRE>
5773: <BLOCKQUOTE class="example">
5774: <P>
5775: <STRONG>Example:</STRONG></P>
5776: <P>
1.3 cvs 5777: The content of the presentation box created to make the chapter number and
5778: section number appear before each section title can be defined by:</P>
1.1 cvs 5779: <PRE>
5780: BOXES
5781: SectionNumBox :
5782: BEGIN
5783: Content : NumSection;
5784: ...
5785: END;
5786: </PRE>
5787: <P>
1.5 cvs 5788: if the <TT>NumSection</TT> variable has been defined in the variable definition
1.3 cvs 5789: section of the presentation schema. Otherwise the <TT>Content</TT> would be
1.1 cvs 5790: written:</P>
5791: <PRE>
5792: BOXES
5793: SectionNumBox :
5794: BEGIN
5795: Content : (VALUE (ChapterCtr, Roman) TEXT '.'
5796: VALUE (SectionCtr, Arabic));
5797: ...
5798: END;
5799: </PRE>
5800: <P>
5801: To specify that a page footer should contain all elements of the <TT>Note</TT>
5802: type are referred to in the page, the following rule is written:</P>
5803: <PRE>
5804: BOXES
5805: NotesFooterBox :
5806: BEGIN
5807: Content : Note;
5808: ...
5809: END;
5810: </PRE>
5811: <P>
1.5 cvs 5812: <TT>Note</TT> is defined as an associated element in the structure schema and
1.1 cvs 5813: NotesFooterBox is created by a page box of the primary view.</P>
5814: </BLOCKQUOTE>
5815: </DIV>
5816:
5817: <DIV class="subsection">
1.6 cvs 5818: <H3><A name=sectc4232>Presentation box creation</A></H3>
1.1 cvs 5819:
5820: <P>
5821: A creation rule specifies that a presentation box should be created when an
5822: element of the type to which the rule is attached appears in the document.</P>
5823: <P>
5824: A keyword specifies the position, relative to the creating box, at which the
5825: created box will be placed in the structure:</P>
5826: <DL>
5827: <DT><TT>CreateFirst</TT></DT>
1.2 cvs 5828: <DD>specifies that the box should be created as the first box of the next lower
5829: level, before any already existing boxes, and only if the beginning of the
1.1 cvs 5830: creating element is visible;
5831: </DD>
5832: <DT><TT>CreateLast</TT></DT>
1.2 cvs 5833: <DD>specifies that the box should be created as the last box of the next lower
5834: level, after any existing boxes, and only if the end of the creating element is
1.1 cvs 5835: visible;
5836: </DD>
5837: <DT><TT>CreateBefore</TT></DT>
1.2 cvs 5838: <DD>specifies that the box should be created before the creating box, on the
5839: same level as the creating box, and only if the beginning of the creating
1.1 cvs 5840: element is visible;
5841: </DD>
5842: <DT><TT>CreateAfter</TT></DT>
1.2 cvs 5843: <DD>specifies that the box should be created after the creating box, on the
5844: same level as the creating box, and only if the beginning of the creating
1.1 cvs 5845: element is visible;
5846: </DD>
5847: <DT><TT>CreateEnclosing</TT></DT>
1.2 cvs 5848: <DD>specifies that the box should be created at the upper level relatively to
5849: the creating box, and that it must contain that creating box and all
5850: presentation boxes created by the same creating box.
1.1 cvs 5851: </DD>
5852: </DL>
5853: <P>
5854: This keyword can be followed by the <TT>Repeated</TT> keyword to indicate that
5855: the box must be created for each part of the creating element. These parts
5856: result from the division of the element by page breaks or column changes. If
5857: the <TT>Repeated</TT> keyword is missing, the box is only created for the
5858: first part of the creating element (<TT>CreateFirst</TT> and
5859: <TT>CreateBefore</TT> rules) or for the last part (<TT>CreateLast</TT> and
5860: <TT>CreateAfter</TT> rules).</P>
5861: <P>
5862: The type of presentation to be created is specified at the end of the rule
5863: between parentheses.</P>
5864: <P>
1.6 cvs 5865: Creation rules cannot appear in the <A href="#sectc427">default
1.1 cvs 5866: presentation rules</A>. The boxes being created should have a
5867: <TT>Content</TT> rule which indicates their <A
1.6 cvs 5868: href="#sectc4231">content</A>.</P>
1.1 cvs 5869: <P>
5870: Creation rules can only appear in the block of rules for the primary view;
5871: creation is provoked by a document element for all views. However, for each
5872: view, the presentation box is only created if the creating element is itself a
5873: box in the view. Moreover, the visibility parameter of the presentation box
5874: can be adjusted to control the creation of the box on a view-by-view
5875: basis.</P>
5876: <PRE>
5877: Creation '(' BoxID ')'
5878: Creation = Create [ 'Repeated' ] .
5879: Create ='CreateFirst' / 'CreateLast' /
5880: 'CreateBefore' / 'CreateAfter' /
5881: 'CreateEnclosing' .
5882: </PRE>
5883: <BLOCKQUOTE class="example">
5884: <P>
5885: <STRONG>Example:</STRONG></P>
5886: <P>
1.3 cvs 5887: Let us define an object type, called Table, which is composed of a sequence of
5888: columns, all having the same fixed width, where the columns are separated by
5889: vertical lines. There is a line to the left of the first column and one to the
5890: right of the last. Each column has a variable number of cells, placed one on
5891: top of the other and separated by horizontal lines. There are no horizontal
5892: lines above the first cell or below the last cell. The text contained in
1.5 cvs 5893: each cell is broken into lines and these lines are centered horizontally in
5894: the cell. The logical structure of this object is defined by:</P>
1.1 cvs 5895: <PRE>
5896: Table = LIST OF (Column);
5897: Column = LIST OF (Cell = Text);
5898: </PRE>
5899:
5900: <DIV class="figure">
5901: <HR>
5902: <PRE>
5903: | | | |
5904: | xx xxxx xxxx |x xxxx xxx xxxxx| x xxx x xxx |
5905: | xxx xxx xxxx x | x xx x xxx | xxxxx xxxx xx |
5906: | xxxxx xxxx |----------------| xxx xxxxx x |
5907: | xxxxx xxx xxxx | xxxx xx xx xxx | xx xx |
5908: | xxx xxxx x xxx | xxxx x xxx x |---------------|
5909: |----------------| xxx xxxx xxxxx | xxxxx xxxxx |
5910: | xxx xxx xxxxxx |----------------| xxx xxxx xxxx |
5911: | xxxx xxxx xx | xxxx xx x xx | xxx xx x xx |
5912: |----------------| xxx xxxxx xxxx | xxxx xxxx xxx |
5913: | xxxxx xxx xxxx | xxxx xx x xx | xxxxx xxx |
5914: |xxxx xx x xxxxxx| xxxx xx xxxxxx | xxxxx xxxxx |
5915: </PRE>
5916: <P align=center>
5917: <EM><A name="table">The design of a table</A></EM></P>
5918: <HR>
5919: </DIV>
5920: <P>
5921: The presentation of the table should resemble the design of the above <A
5922: href="#table">figure</A>. It is defined by the following presentation schema
5923: fragment:</P>
5924: <PRE>
5925: BOXES
5926: VertLine : BEGIN
5927: Width : 0.3 cm;
5928: Height : Enclosing . Height;
5929: VertPos : Top = Enclosing . Top;
5930: HorizPos : Left = Previous . Right;
5931: Content : Graphics 'v';
5932: END;
5933:
5934: HorizLine: BEGIN
5935: Width : Enclosing . Width;
5936: Height : 0.3 cm;
5937: VertPos : Top = Previous . Bottom;
5938: HorizPos : Left = Enclosing . Left;
5939: Content : Graphics 'h';
5940: END;
5941:
5942: RULES
1.6 cvs 5943: Column : BEGIN
5944: CreateBefore (VertLine);
5945: IF LAST CreateAfter (VertLine);
5946: Width : 2.8 cm;
5947: Height : Enclosed . Height;
5948: VertPos : Top = Enclosing . Top;
5949: HorizPos : Left = Previous . Right;
5950: END;
5951:
5952: Cell : BEGIN
5953: IF NOT FIRST CreateBefore (HorizLine);
5954: Width : Enclosing . Width;
5955: Height : Enclosed . Height;
5956: VertPos : Top = Previous . Bottom;
5957: HorizPos : Left = Enclosing . Left;
5958: Line;
5959: Adjust : VMiddle;
5960: END;
1.1 cvs 5961: </PRE>
5962: <P>
5963: It is useful to note that the horizontal position rule of the first vertical
5964: line will not be applied, since there is no preceding box. In this case, the
5965: box is simply placed on the left side of the enclosing box.</P>
5966: </BLOCKQUOTE>
5967: </DIV>
5968:
5969: <DIV class="subsection">
1.6 cvs 5970: <H3><A name=sectc4233>Page layout</A></H3>
1.1 cvs 5971:
5972: <P>
5973: The page models specified in the <TT>Page</TT> rule are defined by boxes
5974: declared in the <TT>BOXES</TT> section of the presentation schema. Pages are
5975: not described as frames which will be filled by the document's text, but as
5976: element are inserted in the flow of the document and which mark the page
5977: breaks. Each of these page break elements contains presentation boxes which
5978: represent the footer boxes of a page followed by header boxes of the next
5979: page. The page box itself is the simple line which separates two pages on the
5980: screen. Both the footer and header boxes placed themselves with respect to
5981: this page box, with the footer being placed above it and the header boxes
5982: being placed above it.</P>
5983: <P>
5984: The boxes created by a page box are headers and footers and can only place
5985: themselves vertically with respect to the page box itself (which is in fact
5986: the separation between two pages). Besides, it is their vertical position
5987: rule which determines whether they are header or footer boxes. Header and
5988: footer boxes must have an explicit vertical position rule (they must not use
5989: the default rule).</P>
5990: <P>
5991: Footer boxes must have an absolute height or inherit the height of their
5992: contents:</P>
5993: <PRE>
5994: Height : Enclosed . Height;
5995: </PRE>
5996: <P>
5997: A page box must have height and width rules and these two rules must be
5998: specified with constant values, expressed in centimeters, inches, or
5999: typographer's points. These two rules are interpreted in a special way for
6000: page boxes: they determine the width of the page and the vertical distance
6001: between two page separators, which is the height of the page and its header
6002: and footer together.</P>
6003: <P>
6004: A page box should also have vertical and horizontal position rules and these
6005: two rules should specify the position on the sheet of paper of the rectangle
6006: enclosing the page's contents. These two rules must position the upper left
6007: corner of the enclosing rectangle in relation to the upper left corner of the
6008: sheet of paper, considered to be the enclosing element. In both rules,
6009: distances must be expressed in fixed units: centimeters (<TT>cm</TT>), inches
6010: (<TT>in</TT>), or typographer's points (<TT>pt</TT>). Thus, rules similar to
6011: the following should be found in the rules for a page box:</P>
6012: <PRE>
6013: BOXES
6014: ThePage :
6015: BEGIN
6016: VertPos : Top = Enclosing . Top + 3 cm;
6017: HorizPos : Left = Enclosing . Left + 2.5 cm;
6018: Width : 16 cm;
6019: Height : 22.5 cm;
6020: END;
6021: </PRE>
6022: <P>
6023: When a document must be page broken, the page models to be constructed are
6024: defined in the <TT>BOXES</TT> section of the presentation schema by declaring
6025: page boxes and header and footer boxes. Also, the <TT>Page</TT> rule is used
6026: to specify to which parts of the document and to which views each model should
6027: be applied.</P>
6028: <P>
6029: The <TT>Page</TT> rule has only one parameter, given between parentheses after
6030: the <TT>Page</TT> keyword. This parameter is the name of the box which must
6031: serve as the model for page construction. When a <TT>Page</TT> rule is
6032: attached to an element type, each time such an element appears in a document,
6033: a page break takes place and the page model indicated in the rule is applied
6034: to all following pages, until reaching the next element which has a
6035: <TT>Page</TT> rule.</P>
6036: <P>
6037: The <TT>Page</TT> rule applies to only one view; if it appears in the primary
6038: view's block of rules, a <TT>Page</TT> rule applies only to that view. Thus,
6039: different page models can be defined for the full document and for its table
6040: of contents, which is another view of the same document. Some views can be
6041: specified with pages, and other views of the same document can be specified
6042: without pages.</P>
6043: <PRE>
6044: 'Page' '(' BoxID ')'
6045: </PRE>
6046: </DIV>
6047:
6048: <DIV class="subsection">
1.6 cvs 6049: <H3><A name=sectc4234>Box copies</A></H3>
1.1 cvs 6050:
6051: <P>
6052: The <TT>Copy</TT> rule can be used for an element which is defined as a
1.7 cvs 6053: reference in the structure schema. In this case, the rule specifies, between
6054: parenthesis, the name of the box (declared in the <TT>BOXES</TT> section)
1.1 cvs 6055: which must be produced when this reference appears in the structure of a
6056: document. The box produced is a copy (same contents, but possible different
6057: presentation) of the box type indicated by the parameter between parentheses,
6058: and which is in the element designated by the reference. The name of a box
6059: can be replaced by type name. Then what is copied is the contents of the
6060: element of this type which is inside the referenced element.</P>
6061: <P>
6062: Whether a box name or type name is given, it may be followed by the name of a
6063: structure schema between parentheses. This signifies that the box or type is
6064: defined in the indicated structure schema and not in the structure schema with
6065: which the rule's presentation schema is associated.</P>
6066: <P>
6067: The <TT>Copy</TT> rule can also be applied to a presentation box. If the
6068: presentation box was created by a reference attribute, the rule is applied as
6069: in the case of a reference element: the contents of the box having the
6070: <TT>Copy</TT> rule are based on the element designated by the reference
6071: attribute. For other presentation boxes, the <TT>Copy</TT> rule takes a type
6072: name parameter which can be followed, between parentheses, by the name of the
6073: structure schema in which the type is defined, if it is not defined in the
6074: same schema. The contents of the box which has this rule are a copy of the
6075: element of this type which is in the element creating the presentation box, or
6076: by default, the box of this type which precedes the presentation box. This
6077: last facility is used, for example, to define the running titles in headers or
6078: footers.</P>
6079: <PRE>
1.6 cvs 6080: 'Copy' '(' BoxTypeToCopy ')' .
1.1 cvs 6081: BoxTypeToCopy = BoxID [ ExtStruct ] /
1.6 cvs 6082: ElemID [ ExtStruct ] .
6083: ExtStruct = '(' ElemID ')' .
1.1 cvs 6084: </PRE>
6085: <P>
6086: Like the creation rules, the <TT>Copy</TT> rule cannot appear in the <A
1.6 cvs 6087: href="#sectc427">default presentation rules</A>. Moreover, this rule
1.1 cvs 6088: can only appear in the primary view's block of rules; the copy rule is applied
6089: to all views.</P>
6090: <BLOCKQUOTE class="example">
6091: <P>
6092: <STRONG>Example:</STRONG></P>
6093: <P>
6094: If the following definitions are in the structure schema:</P>
6095: <PRE>
6096: Body = LIST OF (Chapter =
6097: BEGIN
6098: ChapterTitle = Text;
6099: ChapterBody = SectionSeq;
6100: END);
6101: RefChapter = REFERENCE (Chapter);
6102: </PRE>
6103: <P>
6104: then the following presentation rules (among many other rules in
1.3 cvs 6105: the presentation schema) can be specified:</P>
1.1 cvs 6106: <PRE>
6107: COUNTERS
6108: ChapterCtr : RANK OF Chapter;
6109: BOXES
6110: ChapterNumber :
6111: BEGIN
6112: Content : (VALUE (ChapterCtr, URoman));
6113: ...
6114: END;
6115: RULES
6116: Chapter :
6117: BEGIN
6118: CreateFirst (ChapterNumber);
6119: ...
6120: END;
6121: RefChapter :
6122: BEGIN
6123: Copy (ChapterNumber);
6124: ...
6125: END;
6126: </PRE>
6127: <P>
1.4 cvs 6128: which makes the number of the chapter designated by the reference appear in
6129: uppercase roman numerals, in place of the reference to a chapter itself.
6130: Alternatively, the chapter title can be made to appear in place of the
1.1 cvs 6131: reference by writing this <TT>Copy</TT>rule:</P>
6132: <PRE>
6133: Copy (ChapterTitle);
6134: </PRE>
6135: <P>
6136: To define a header box, named <TT>RunningTitle</TT>, which contains the title
6137: of the current chapter, the box's contents are defined in this way:</P>
6138: <PRE>
6139: BOXES
6140: RunningTitle :
6141: Copy (ChapterTitle);
6142: </PRE>
6143: </BLOCKQUOTE>
6144: </DIV>
6145: </DIV>
6146: <HR>
6147: </DIV>
6148:
6149: <DIV class="chapter">
1.6 cvs 6150: <H1><A name=sect5>The T language</A></H1>
1.1 cvs 6151:
6152:
6153: <DIV class="section">
1.6 cvs 6154: <H2><A name=sectb51>Document translation</A></H2>
1.1 cvs 6155:
6156: <P>
6157: Because of its document model, Thot can produce documents in a high-level
6158: abstract form. This form, called the <EM>canonical form</EM> is specific to
6159: Thot; it is well suited to the editor's manipulations, but it does not
6160: necessarily suit other operations which might be applied to documents. Because
6161: of this, the Thot editor offers the choice of saving documents in its own form
6162: (the canonical form) or a format defined by the user. In the latter case, the
6163: Thot document is transformed by the translation program. This facility can
6164: also be used to export documents from Thot to systems using other
6165: formalisms.</P>
6166:
6167: <DIV class="subsection">
1.6 cvs 6168: <H3><A name=sectc511>Translation principles</A></H3>
1.1 cvs 6169:
6170: <P>
6171: Document translation allows the export of documents to other systems which do
6172: not accept Thot's canonical form. Translation can be used to export document
6173: to source-based formatters like T<SUB><BIG>E</BIG></SUB>X,
6174: L<SUP>A</SUP>T<SUB><BIG>E</BIG></SUB>X, and <TT>troff</TT>. It can also be
6175: used to translate documents into interchange formats like SGML or HTML. To
6176: allow the widest range of possible exports, Thot does not limit the choice of
6177: translations, but rather allows the user to define the formalisms into which
6178: documents can be translated.</P>
6179: <P>
6180: For each document or object class, a set of translation rules can be defined,
6181: specifying how the canonical form should be transformed into a given
6182: formalism. These translation rules are grouped into <EM>translation
6183: schemas</EM>, each schema containing the rules necessary to translate a
6184: generic logical structure (document or object structure) into a particular
6185: formalism. The same generic logical structure can have several different
6186: translation schemas, each defining translation rules for a different
6187: formalism.</P>
6188: <P>
6189: Like presentation schemas, translation schemas are generic. Thus, they apply
6190: to an entire object or document class and permit translation of all documents
6191: or objects of that class.</P>
6192: </DIV>
6193:
6194: <DIV class="subsection">
1.6 cvs 6195: <H3><A name=sectc512>Translation procedure</A></H3>
1.1 cvs 6196:
6197: <P>
6198: The translator works on the specific logical structure of the document being
6199: translated. It traverses the primary tree of this logical structure in
6200: pre-order and, at each node encountered, it applies the corresponding
6201: translation rules defined in the translation schema. Translation can be
6202: associated:</P>
6203: <UL>
6204: <LI>with element types defined in the structure schema,
6205: <LI>with global or local attributes defined in the structure schema,
6206: <LI>with specific presentation rules,
1.2 cvs 6207: <LI>with the content of the leaves of the structure (characters, symbols and
1.1 cvs 6208: graphical elements)
6209: </UL>
6210: <P>
6211: Thus, for each node, the translator applies all rules associated with the
6212: element type, all rules associated with each attribute (local or global)
6213: carried by the element, and if the element is a leaf of the tree, it also
1.10 cvs 6214: applies translation rules for characters, symbols, or graphical elements,
1.1 cvs 6215: depending on the type of the leaf.</P>
6216: <P>
6217: Rules associated with the content of leaves are different from all other
6218: rules: they specify only how to translate character strings, symbols, and
6219: graphical elements. All other rules, whether associated with element types,
6220: with specific presentation rules or with attributes, are treated similarly.
6221: These rules primarily allow:</P>
6222: <UL>
1.2 cvs 6223: <LI>generation of a text constant or variable before or after the contents of
1.1 cvs 6224: an element,
1.2 cvs 6225: <LI>modification of the order in which elements appear after translation,
1.1 cvs 6226: <LI>removal of an element in the translated document,
6227: <LI>and writing messages on the user's terminal during translation.
6228: </UL>
6229: </DIV>
6230: </DIV>
6231:
6232: <DIV class="section">
1.6 cvs 6233: <H2><A name=sectb52>Translation definition language</A></H2>
1.1 cvs 6234:
6235: <P>
6236: Translation schemas are written in a custom language, called T, which is
6237: described in the rest of this chapter. The grammar of T is specified using
1.6 cvs 6238: the same <A href="#sectc321">meta-language</A> as was used for the S and P
1.1 cvs 6239: languages and the translation schemas are written using the same conventions
6240: as the structure and presentation schemas. In particular, the keywords of the
6241: T language (the stings between apostrophes in the following syntax rules) can
6242: be written in any combination of upper-case and lower-case letters, but
6243: identifiers created by the programmer must always be written in the same
6244: way.</P>
6245:
6246: <DIV class="subsection">
1.6 cvs 6247: <H3><A name=sectc521>Organization of a translation schema</A></H3>
1.1 cvs 6248:
6249: <P>
6250: A translation schema is begun by the <TT>TRANSLATION</TT> keyword and is
6251: terminated by the <TT>END</TT> keyword. The <TT>TRANSLATION</TT> keyword is
6252: followed by the name of the generic structure for which a translation is being
6253: defined and a semicolon. This name must be identical to the name which
6254: appears after the <TT>STRUCTURE</TT> keyword in the corresponding structure
6255: schema.</P>
6256: <P>
6257: After this declaration of the structure, the following material appears in
6258: order:</P>
6259: <UL>
6260: <LI>the length of lines produced by the translation,
6261: <LI>the character delimiting the end of the line,
6262: <LI>the character string which the translator will insert if it must
6263: line-break the translated text,
6264: <LI>declarations of
6265: <UL>
6266: <LI>buffers,
6267: <LI>counters,
6268: <LI>constants,
6269: <LI>variables,
6270: </UL>
6271: <LI>translation rules associated with element types,
6272: <LI>translation rules associated with attributes,
6273: <LI>translation rules associated with specific presentation rules,
6274: <LI>translation rules associated with characters strings, symbols and
6275: graphical elements.
6276: </UL>
6277: <P>
6278: Each of these sections is introduced by a keyword followed by a sequence of
6279: declarations. All of these sections are optional, expect for the translation
6280: rules associated with element types. Many <TT>TEXTTRANSLATE</TT> sections can
6281: appear, each defining the rules for translating character strings of a
6282: particular alphabet.</P>
6283: <PRE>
6284: TransSchema ='TRANSLATION' ElemID ';'
6285: [ 'LINELENGTH' LineLength ';' ]
6286: [ 'LINEEND' CHARACTER ';' ]
6287: [ 'LINEENDINSERT' STRING ';' ]
6288: [ 'BUFFERS' BufferSeq ]
6289: [ 'COUNTERS' CounterSeq ]
6290: [ 'CONST' ConstSeq ]
6291: [ 'VAR' VariableSeq ]
6292: 'RULES' ElemSeq
6293: [ 'ATTRIBUTES' AttrSeq ]
6294: [ 'PRESENTATION' PresSeq ]
6295: < 'TEXTTRANSLATE' TextTransSeq >
6296: [ 'SYMBTRANSLATE' TransSeq ]
6297: [ 'GRAPHTRANSLATE' TransSeq ]
6298: 'END' .
6299: </PRE>
6300: </DIV>
6301:
6302: <DIV class="subsection">
1.6 cvs 6303: <H3><A name=sectc522>Line length</A></H3>
1.1 cvs 6304:
6305: <P>
6306: If a <TT>LINELENGTH</TT> instruction is present after the structure
6307: declaration, the translator divides the text it produces into lines, each line
6308: having a length less than or equal to the integer which follows the
6309: <TT>LINELENGTH</TT> keyword. This maximum line length is expressed as a
6310: number of characters. The end of the line is marked by the character defined
6311: by the <TT>LINEEND</TT> instruction. When the translator breaks the lines on
6312: a space character in generated text, this space will be replaced by the
6313: character string defined by the <TT>LINEENDINSERT</TT> instruction.</P>
6314: <P>
6315: If the <TT>LINEEND</TT> instruction is not defined then the linefeed character
6316: (octal code 12) is used as the default line end character. If the
6317: <TT>LINEENDINSERT</TT> instruction is not defined, the linefeed character is
6318: inserted at the end of the produced lines. If there is no <TT>LINELENGTH</TT>
6319: instruction, the translated text is not divided into lines. Otherwise, if the
6320: translation rules generate line end marks, these marks remain in the
6321: translated text, but the length of the lines is not controlled by the
6322: translator.</P>
6323: <PRE>
6324: LineLength = NUMBER .
6325: </PRE>
6326: <BLOCKQUOTE class="example">
6327: <P>
6328: <STRONG>Example:</STRONG></P>
6329: <P>
1.3 cvs 6330: To limit the lines produced by the translator to a length of 80 characters, the
6331: following rule is written at the beginning of the translation schema.</P>
1.1 cvs 6332: <PRE>
6333: LineLength 80;
6334: </PRE>
6335: </BLOCKQUOTE>
6336: </DIV>
6337:
6338: <DIV class="subsection">
1.6 cvs 6339: <H3><A name=sectc523>Buffers</A></H3>
1.1 cvs 6340:
6341: <P>
6342: A buffer is a unit of memory managed by the translator, which can either
6343: contain text read from the terminal during the translation (see the <A
1.6 cvs 6344: href="#sectc5212"><TT>Read</TT> rule</A>), or the name of the last picture
1.1 cvs 6345: (bit-map) encountered by the translator in its traversal of the document.
1.2 cvs 6346: Remember the pictures are stored in files that are separate for the document
1.1 cvs 6347: files and that the canonical form contains only the names of the files in
1.2 cvs 6348: which the pictures are found.</P>
1.1 cvs 6349: <P>
6350: Thus, there are two types of buffers: buffers for reading from the terminal
1.2 cvs 6351: (filled by the <TT>Read</TT> rule) and the buffer of picture names (containing
6352: the name of the last picture encountered). A translation schema can use
6353: either type, one or several read buffers and one (and only one) picture name
1.1 cvs 6354: buffer.</P>
6355: <P>
6356: If any buffers are used, the <TT>BUFFERS</TT> keyword must be present,
6357: followed by declarations of every buffer used in the translation schema. Each
6358: buffer declaration is composed only of the name of the buffer, chosen freely
1.2 cvs 6359: by the programmer. The picture name buffer is identified by the
1.1 cvs 6360: <TT>Picture</TT> keyword, between parentheses, following the buffer name. The
6361: <TT>Picture</TT> keyword may only appear once. Each buffer declaration is
6362: terminated by a semicolon.</P>
6363: <PRE>
6364: BufferSeq = Buffer < Buffer > .
6365: Buffer = BufferID [ '(' 'Picture' ')' ] ';' .
6366: BufferID = NAME .
6367: </PRE>
6368: <BLOCKQUOTE class="example">
6369: <P>
6370: <STRONG>Example:</STRONG></P>
6371: <P>
1.3 cvs 6372: The following buffer declarations create a picture name buffer named
1.2 cvs 6373: <TT>pictureName</TT> and a read buffer named <A
1.1 cvs 6374: name="destname"><TT>DestName</TT></A>:</P>
6375: <PRE>
6376: BUFFERS
1.2 cvs 6377: pictureName (Picture); DestName;
1.1 cvs 6378: </PRE>
6379: </BLOCKQUOTE>
6380: </DIV>
6381:
6382: <DIV class="subsection">
1.6 cvs 6383: <H3><A name=sectc524>Counters</A></H3>
1.1 cvs 6384:
6385: <P>
6386: Certain translation rules generate text that varies according to the context
6387: of the element to which the rules apply. Variable text is defined either in
1.6 cvs 6388: the <A href="#sectc526"><TT>VAR</TT> section</A> of the translation schema or
1.1 cvs 6389: in the rule itself (see the <TT>Create</TT> and <TT>Write</TT> rules). Both
6390: types of definition rely on counters for the calculation of variable
6391: material.</P>
6392: <P>
6393: There are two types of counter: counters whose value is explicitely computed
1.6 cvs 6394: by applying <A href="#sectc5221"><TT>Set</TT> and <TT>Add</TT> rules</A>, and
1.1 cvs 6395: counters whose value is computed by a function associated with the counter.
6396: Those functions allow the same calculations as can be used in presentation
6397: schemas. As in a presentation schema, counters must be defined in the
6398: <TT>COUNTERS</TT> section of the translation schema before they are used.</P>
6399: <P>
6400: When counters are used in a translation schema, the <TT>COUNTERS</TT> keyword
6401: is followed by the declarations of every counter used. Each declaration is
6402: composed of the counter's name possibly followed by a colon and the counting
6403: function to be used for the counter. The declaration is terminated by a
6404: semi-colon. If the counter is explicitely computed by <TT>Set</TT> and
6405: <TT>Add</TT> rules, no counting function is indicated. If a counting function
6406: is indicated, <TT>Set</TT> and <TT>Add</TT> rules cannot be applied to that
6407: counter.</P>
6408: <P>
6409: The counting function indicates how the counter's value will be computed.
6410: Three functions are available: <TT>Rank</TT>, <TT>Rlevel</TT>, and
6411: <TT>Set</TT>.</P>
6412: <UL>
1.5 cvs 6413: <LI><TT>Rank of ElemID</TT> indicates that the counter's value is the rank of
6414: the element of type <TT>ElemID</TT> which encloses the element for which the
1.2 cvs 6415: counter is being evaluated. For the purposes of this function, an element of
1.5 cvs 6416: type <TT>ElemID</TT> is considered to enclose itself. This function is
6417: primarily used when the element of type <TT>ElemID</TT> is part of an
1.2 cvs 6418: aggregate or list, in which case the counter's value is the element's rank in
1.5 cvs 6419: its list or aggregate. Note that, unlike the <TT>Rank</TT> function for
6420: presentation schemas, the <TT>Page</TT> keyword cannot be used in place of the
1.1 cvs 6421: <TT>ElemID</TT>.
6422: <P>
6423: The type name <TT>ElemID</TT> can be followed by an integer. That number
6424: represents the relative level, among the ancestors of the concerned element,
6425: of the element whose rank is asked. If that relative level <I>n</I> is
1.5 cvs 6426: unsigned, the <I>n<SUP>th</SUP></I> element of type <TT>ElemID</TT> encountered
6427: when travelling the logical structure from the root to the concerned element is
1.1 cvs 6428: taken into account. If the relative level is negative, the logical structure
6429: is travelled in the other direction, from the concerned element to the
6430: root.</P>
1.5 cvs 6431: <LI><TT>Rlevel of ElemID</TT> indicates that the counter's values is the
1.2 cvs 6432: relative level in the tree of the element for which the counter is being
6433: evaluated. The counter counts the number of elements of type <TT>ElemID</TT>
6434: which are found on the path between the root of the document's logical
6435: structure tree and the element (inclusive).
1.5 cvs 6436: <LI><TT>Set n on Type1 Add m on Type2</TT> indicates that the counter's value
1.2 cvs 6437: is calculated as follows: in traversing the document from the beginning to
6438: the element for which the counter is being evaluated, the counter is set to
1.5 cvs 6439: the value <TT>n</TT> each time a <TT>Type1</TT> element is encountered and is
6440: incremented by the amount <TT>m</TT> each time a <TT>Type2</TT> element is
6441: encountered. The initial value <TT>n</TT> and the increment <TT>m</TT> are
1.1 cvs 6442: integers.
6443: </UL>
6444: <P>
6445: As in a presentation schema, the <TT>Rank</TT> and <TT>Set</TT> functions can
6446: be modified by a numeric attribute which changes their initial value. This is
6447: indicated by the <TT>Init</TT> keyword followed by the numeric attribute's
6448: name. The <TT>Set</TT> function takes the value of the attribute instead of
6449: the <TT>InitValue</TT> (<TT>n</TT>). For the <TT>Rank</TT> function, the
6450: value of the attribute is considered to be the rank of the first element of
6451: the list (rather than the normal value of 1). Subsequent items in the list
6452: have their ranks shifted accordingly. In both cases, the attribute must be
6453: numeric and must be a local attribute of the root of the document itself.</P>
6454: <PRE>
6455: CounterSeq = Counter < Counter > .
6456: Counter = CounterID [ ':' CounterFunc ] ';' .
6457: CounterID = NAME .
6458: CounterFunc = 'Rank' 'of' ElemID [ SLevelAsc ]
6459: [ 'Init' AttrID ] /
6460: 'Rlevel' 'of' ElemID /
6461: 'Set' InitValue 'On' ElemID
6462: 'Add' Increment 'On' ElemID
6463: [ 'Init' AttrID ] .
6464: SLevelAsc = [ '-' ] LevelAsc .
6465: LevelAsc = NUMBER .
6466: InitValue = NUMBER .
6467: Increment = NUMBER .
6468: ElemID = NAME .
6469: AttrID = NAME .
6470: </PRE>
6471: <BLOCKQUOTE class="example">
6472: <P>
6473: <STRONG>Example:</STRONG></P>
6474: <P>
6475: If the body of a chapter is defined in the structure schema by:</P>
6476: <PRE>
6477: Chapter_Body = LIST OF
6478: (Section = BEGIN
6479: Section_Title = Text;
6480: Section_Body = BEGIN
6481: Paragraphs;
6482: Section;
6483: END;
6484: END
6485: );
6486: </PRE>
6487: <P>
1.3 cvs 6488: (sections are defined recursively), a counter can be defined giving the <A
1.4 cvs 6489: name="sectnum">number of a section</A> within its level in the hierarchy:</P>
1.1 cvs 6490: <PRE>
6491: COUNTERS
6492: SectionNumber : Rank of Section;
6493: </PRE>
6494: <P>
6495: A counter holding the hierarchic level of a section:</P>
6496: <PRE>
6497: SectionLevel : Rlevel of Section;
6498: </PRE>
6499: <P>
1.5 cvs 6500: A <A name="uniquenum">counter</A> which sequentially numbers all the document's
1.1 cvs 6501: sections, whatever their hierarchic level:</P>
6502: <PRE>
6503: UniqueSectNum : Set 0 on Document Add 1 on Section;
6504: </PRE>
6505: </BLOCKQUOTE>
6506: </DIV>
6507:
6508: <DIV class="subsection">
1.6 cvs 6509: <H3><A name=sectc525>Constants</A></H3>
1.1 cvs 6510:
6511: <P>
6512: A common feature of translation rules is the generation of constant text. This
6513: text can be defined in the rule that generates it (see for example the <A
1.6 cvs 6514: href="#sectc5210"><TT>Create</TT></A> and <A href="#sectc5211"><TT>Write</TT></A>
1.1 cvs 6515: rules); but it can also be defined once in the constant declaration section
6516: and used many times in different rules. The latter option is preferable when
6517: the same text is used in several rules or several <A
1.6 cvs 6518: href="#sectc526">variables</A>.</P>
1.1 cvs 6519: <P>
6520: The <TT>CONST</TT> keyword begins the constant declaration section of the
6521: translation schema. It must be omitted if no constants are declared. Each
6522: constant declaration is composed of the constant name, an equals sign, and the
6523: constant's value, which is a character string between apostrophes. A constant
6524: declaration is terminated by a semicolon.</P>
6525: <PRE>
6526: ConstSeq = Const < Const > .
6527: Const = ConstID '=' ConstValue ';' .
6528: ConstID = NAME .
6529: ConstValue = STRING .
6530: </PRE>
6531: <BLOCKQUOTE class="example">
6532: <P>
6533: <STRONG><A name="levelexample">Example:</A></STRONG></P>
6534: <P>
1.5 cvs 6535: The following rule assigns the name <TT>TxtLevel</TT> to the character string
1.1 cvs 6536: ``Level'':</P>
6537: <PRE>
6538: CONST
6539: TxtLevel = 'Level';
6540: </PRE>
6541: </BLOCKQUOTE>
6542: </DIV>
6543:
6544: <DIV class="subsection">
1.6 cvs 6545: <H3><A name=sectc526>Variables</A></H3>
1.1 cvs 6546:
6547: <P>
1.10 cvs 6548: Variables allow to define variable text which is generated by the
6549: <TT>Create</TT> and <TT>Write</TT> rules. They are also used to define
6550: file names which are used in the <TT>Create</TT>, <TT>ChangeMainFile</TT>,
6551: and <TT>Indent</TT> rules. Variables can be defined either
1.1 cvs 6552: in the <TT>VAR</TT> section of the translation schema or directly in the rules
1.10 cvs 6553: which use them. Variables that define file names must be declared in the
1.1 cvs 6554: <TT>VAR</TT> section, and when the same variable is used several times in the
6555: translation schema, it makes sense to define it globally in the <TT>VAR</TT>
6556: section. This section is only present if at least one variable is defined
6557: globally.</P>
6558: <P>
6559: After the <TT>VAR</TT> keyword, each global variable is defined by its name, a
6560: colon separator and a sequence of functions (at least one function). Each
6561: variable definition is terminated by a semicolon. Functions determine the
6562: different parts which together give the value of the variable. The value is
6563: obtained by concatenating the strings produced by each of the functions. Seven
6564: types of functions are available. Each variable definition may use any number
6565: of functions of each type.</P>
6566: <UL>
1.2 cvs 6567: <LI>The function <TT>Value(Counter)</TT>returns a string representing the
6568: value taken by the counter when it is evaluated for the element in whose rule
6569: the variable is used. The counter must have been declared in the
1.5 cvs 6570: <TT>COUNTERS</TT> section of the translation schema. When the counter is
1.2 cvs 6571: expressed in arabic numerals, the counter name can be followed by a colon and
6572: an integer indicating a minimum length (number of characters) for the string;
6573: if the counter's value is normally expressed with fewer characters than the
6574: required minimum, zeroes are added to the front of the string to achieve the
1.5 cvs 6575: minimum length.
1.1 cvs 6576: <P>
6577: By default, the counter value is written in arabic digits. If another
6578: representation of that value is needed, the counter name must be followed by a
6579: comma and one of the following keywords:</P>
6580: <UL>
6581: <LI><TT>Arabic</TT>: arabic numerals (default value),
6582: <LI><TT>LRoman</TT>: lower-case roman numerals,
6583: <LI><TT>URoman</TT>: upper-case roman numerals,
6584: <LI><TT>Uppercase</TT>: upper-case letter,
6585: <LI><TT>Lowercase</TT>: lower-case letter.
6586: </UL>
1.2 cvs 6587: <LI>The function <TT>FileDir</TT>, without parameter, returns a string
6588: representing the name of the directory of the output file that has been given
6589: as a parameter to the translation program. The string includes a character '/'
6590: at the end.
6591: <LI>The function <TT>FileName</TT>, without parameter, returns a string
6592: representing the name of the output file that has been given as a parameter to
6593: the translation program. The file extension (the character string that
6594: terminate the file name, after a dot) is not part of that string.
6595: <LI>The function <TT>Extension</TT>, without parameter, returns a string
6596: representing the extension of the file name. That string is empty if the file
6597: name that has been given as a parameter to the translation program has no
6598: extension. If there is an extension, its first character is a dot.
6599: <LI>The function <TT>DocumentName</TT>, without parameter, returns a string
6600: representing the name of the document being translated.
6601: <LI>The function <TT>DocumentDir</TT>, without parameter, returns a string
6602: representing the directory containing the document being translated.
6603: <LI>The function formed by the name of a constant returns that constant's
1.1 cvs 6604: value.
1.2 cvs 6605: <LI>The function formed by a character string between apostrophes returns that
1.1 cvs 6606: string.
1.2 cvs 6607: <LI>The function formed by the name of a buffer returns the contents of that
6608: buffer. If the named buffer is the picture buffer, then the name of the last
6609: picture encountered is returned. Otherwise, the buffer is a read buffer and
6610: the value returned is text previously read from the terminal. If the buffer
6611: is empty (no picture has been encountered or the <TT>Read</TT> rule has not
6612: been executed for the buffer), then the empty string is returned.
6613: <LI>The function formed by an attribute name takes the value of the indicated
6614: attribute for the element to which the variable applies. If the element does
6615: not have that attribute, then the element's ancestor are searched toward the
6616: root of the tree. If one of the ancestors does have the attribute then its
6617: value is used. If no ancestors have the attribute, then the value of the
1.1 cvs 6618: function is the empty string.
6619: </UL>
6620: <PRE>
6621: VariableSeq = Variable < Variable > .
6622: Variable = VarID ':' Function < Function > ';' .
6623: VarID = NAME .
6624: Function ='Value' '(' CounterID [ ':' Length ]
6625: [ ',' CounterStyle ] ')' /
6626: 'FileDir' / 'FileName' / 'Extension' /
6627: 'DocumentName' / 'DocumentDir' /
6628: ConstID / CharString /
6629: BufferID / AttrID .
6630: Length = NUMBER .
6631: CounterStyle= 'Arabic' / 'LRoman' / 'URoman' /
6632: 'Uppercase' / 'Lowercase' .
6633: CharString = STRING .
6634: </PRE>
6635: <BLOCKQUOTE class="example">
6636: <P>
6637: <STRONG>Example:</STRONG></P>
6638: <P>
1.3 cvs 6639: To create, at the beginning of each section of the translated document, text
6640: composed of the string ``Section'' followed by the section number, the
1.5 cvs 6641: following <A name="varsectexample">variable definition</A> might be used:</P>
1.1 cvs 6642: <PRE>
6643: VAR
6644: SectionVar : 'Section' Value(SectionNumber);
6645: </PRE>
6646: <P>
6647: (see the definition of <A href="#sectnum"><TT>SectionNumber</TT></A>).</P>
6648: <P>
6649: The following variable definition can be used to create, at the beginning of
6650: each section, the text ``Level'' followed by the hierarchical level of the
6651: section. It used the constant defined above.</P>
6652: <PRE>
6653: LevelVar : TxtLevel Value(SectionLevel);
6654: </PRE>
6655: <P>
1.5 cvs 6656: (see the definitions of <A href="#sectnum"><TT>SectionLevel</TT></A> and of
6657: <A href="#levelexample"><TT>TxtLevel</TT></A>).</P>
1.1 cvs 6658: <P>
1.5 cvs 6659: To generate the translation of each section in a different file (see
1.6 cvs 6660: <A href="#sectc5220">rule <TT>ChangeMainFile</TT></A>), the name of these
1.1 cvs 6661: files might be defined by the following variable:</P>
6662: <PRE>
6663: VarOutpuFile : FileName Value(SectionNumber)
6664: Extension;
6665: </PRE>
6666: <P>
1.4 cvs 6667: If <TT>output.txt</TT> is the name of the <A name="varoutputfile">output
6668: file</A> specified when starting the translation program, translated sections
6669: are written in files <TT>output1.txt</TT>, <TT>output2.txt</TT>, etc.</P>
1.1 cvs 6670: </BLOCKQUOTE>
6671: </DIV>
6672:
6673: <DIV class="subsection">
1.6 cvs 6674: <H3><A name=sectc527>Translating structure elements</A></H3>
1.1 cvs 6675:
6676: <P>
6677: The <TT>RULES</TT> keyword introduces the translation rules which will be
6678: applied to the various structured element types. Translation rules can be
6679: specified for each element type defined in the structure schema, including the
6680: base types defined implicitly, whose names are <TT>TEXT_UNIT</TT>,
6681: <TT>PICTURE_UNIT</TT>, <TT>SYMBOL_UNIT</TT>, <TT>GRAPHIC_UNIT</TT> and
1.2 cvs 6682: <TT>PAGE_UNIT</TT>. But it is not necessary to specify rules for every
6683: defined type.</P>
1.1 cvs 6684: <P>
6685: If there are no translation rules for an element type, the elements that it
6686: contains (and which may have rules themselves) will still be translated, but
6687: the translator will produce nothing for the element itself. To make the
6688: translator completely ignore the content of an element the <A
1.6 cvs 6689: href="#sectc5217"><TT>Remove</TT> rule</A> must be used.</P>
1.1 cvs 6690: <P>
6691: The translation rules for an element type defined in the structure schema are
6692: written using the name of the type followed by a colon and the list of
1.6 cvs 6693: applicable rules. When the element type is a <A href="#sectd3285">mark pair</A>,
1.1 cvs 6694: but only in this case, the type name must be preceded by the <TT>First</TT> or
6695: <TT>Second</TT> keyword. This keyword indicates whether the rules that follow
6696: apply to the first or second mark of the pair.</P>
6697: <P>
6698: The list of rules can take several forms. It may be a simple non-conditional
6699: rule. It can also be formed by a condition followed by one or more simple
6700: rules. Or it can be a block of rules beginning with the <TT>BEGIN</TT>
6701: keyword and ending with the <TT>END</TT> keyword and a semicolon. This block
6702: of rules can contain one or more simple rules and/or one or more conditions,
6703: each followed by one or more simple rules.</P>
6704: <PRE>
6705: ElemSeq = TransType < TransType > .
6706: TransType = [ FirstSec ] ElemID ':' RuleSeq .
6707: FirstSec = 'First' / 'Second' .
6708: RuleSeq = Rule / 'BEGIN' < Rule > 'END' ';' .
6709: Rule = SimpleRule / ConditionBlock .
6710: ConditionBlock = 'IF' ConditionSeq SimpleRuleSeq .
6711: SimpleRuleSeq = 'BEGIN' < SimpleRule > 'END' ';' /
6712: SimpleRule .
6713: </PRE>
6714: </DIV>
6715:
6716: <DIV class="subsection">
1.6 cvs 6717: <H3><A name=sectc528>Conditional rules</A></H3>
1.1 cvs 6718:
6719: <P>
6720: In a translation schema, the translation rules are either associated with
6721: element types or with attribute values or with a specific presentation. They
6722: are applied by the translator each time an element of the corresponding type
6723: is encountered in the translated document or each time the attribute value is
6724: carried by an element or also, each time the specific translation is attached
6725: to an element. This systematic application of the rules can be relaxed: it is
6726: possible to add a condition to one or more rules, so that these rules are only
6727: applied when the condition is true.</P>
6728: <P>
6729: A condition begins with the keyword <TT>IF</TT>, followed by a sequence of
6730: elementary conditions. Elementary conditions are separated from each other by
6731: the <TT>AND</TT> keyword. If there is only one elementary condition, this
6732: keyword is absent. The rules are only applied if all the elementary
6733: conditions are true. The elementary condition can be negative; it is then
6734: preceded by the <TT>NOT</TT> keyword.</P>
6735: <P>
6736: When the translation rule(s) controlled by the condition apply to a reference
6737: element or a reference attribute, an elementary condition can also apply to
6738: element referred by this reference. The <TT>Target</TT> keyword is used for
6739: that purpose. It must appear before the keyword defining the condition
6740: type.</P>
6741: <P>
6742: Depending on their type, some conditions may apply either to the element with
1.5 cvs 6743: which they are associated, or to one of its ancestor. In the case of an
1.1 cvs 6744: ancestor, the key word <TT>Ancestor</TT> must be used, followed by</P>
6745: <UL>
1.2 cvs 6746: <LI>either an integer which represents the number of levels in the tree
6747: between the element and the ancestor of interest,
6748: <LI>or the type name of the ancestor of interest. If that type is defined in
6749: a separate structure schema, the name of that schema must follow between
1.1 cvs 6750: parentheses.
6751: </UL>
6752: <P>
1.2 cvs 6753: There is a special case for the parent element, which can be simply written
1.5 cvs 6754: <TT>Parent</TT> instead of <TT>Ancestor 1</TT>.</P>
1.1 cvs 6755: <P>
6756: Only conditions <TT>First</TT>, <TT>Last</TT>, <TT>Referred</TT>,
6757: <TT>Within</TT>, <TT>Attributes</TT>, <TT>Presentation</TT>, <TT>Comment</TT>
6758: and those concerning an attribute or a specific presentation can apply to an
6759: ancestor. Conditions <TT>Defined</TT>, <TT>FirstRef</TT>, <TT>LastRef</TT>,
6760: <TT>ExternalRef</TT>, <TT>Alphabet</TT>, <TT>FirstAttr</TT>,
6761: <TT>LastAttr</TT>, <TT>ComputedPage</TT>, <TT>StartPage</TT>,
6762: <TT>UserPage</TT>, <TT>ReminderPage</TT>, <TT>Empty</TT> cannot be preceded by
6763: keywords <TT>Parent</TT> or <TT>Ancestor</TT>.</P>
6764: <P>
6765: In condition <TT>Referred</TT> and in the condition that applies to a named
1.5 cvs 6766: attribute, a symbol '<TT>*</TT>' can indicate that the condition is related
6767: only to the element itself. If this symbol is not present, not only the
6768: element is considered, but also its ancestor, at any level.</P>
1.1 cvs 6769: <P>
6770: The form of an elementary condition varies according to the type of
6771: condition.</P>
6772:
6773: <DIV class="subsubsection">
1.6 cvs 6774: <H4><A name=sectd5281>Conditions based on the logical position of the element</A></H4>
1.1 cvs 6775:
6776: <P>
6777: The condition can be on the position of the element in the document's logical
6778: structure tree. It is possible to test whether the element is the first
6779: (<TT>First</TT>) or last (<TT>Last</TT>) among its siblings or if it is not
6780: the first (<TT>NOT First</TT>) or not the last (<TT>NOT Last</TT>).</P>
6781: <P>
6782: It is also possible to test if the element is contained in an element of a
6783: given type (<TT>Within</TT>) or if it is not (<TT>NOT Within</TT>). If that
6784: element type is defined in a structure schema which is not the one which
6785: corresponds to the translation schema, the type name of this element must be
6786: followed, between parentheses, by the name of the structure schema which
6787: defines it.</P>
6788: <P>
6789: If the keyword <TT>Within</TT> is preceded by <TT>Immediately</TT>, the
6790: condition is satisfied only if the <EM>parent</EM> element has the type
6791: indicated. If the word <TT>Immediately</TT> is missing, the condition is
6792: satisfied if any <EM>ancestor</EM> has the type indicated.</P>
6793: <P>
6794: An integer <I>n</I> can appear between the keyword <TT>Within</TT> and the
6795: type. It specifies the number of ancestors of the indicated type that must be
6796: present for the condition to be satisfied. If the keyword
6797: <TT>Immediately</TT> is also present, the <I>n</I> immediate ancestors of the
6798: element must have the indicated type. The integer <I>n</I> must be positive
6799: or zero. It can be preceded by <TT><</TT> or <TT>></TT> to indicate a
6800: maximum or minimum number of ancestors. If these symbols are missing, the
6801: condition is satisfied only if it exists exactly <I>n</I> ancestors. When
6802: this number is missing, it is equivalent to > 0.</P>
1.11 cvs 6803: <P>
6804: If the condition applies to translation rules associated with an attribute,
6805: i.e. if it is in the <TT>ATTRIBUTES</TT> section of the presentation schema,
6806: the condition can be simply an element name. Translation rules are then
6807: executed only if the attribute is attached to an element of that type.
6808: The keyword <TT>NOT</TT> before the element name indicates that the
6809: translation rules must be executed only if the element is not of the type
6810: indicated.</P>
1.1 cvs 6811: </DIV>
6812:
6813: <DIV class="subsubsection">
1.6 cvs 6814: <H4><A name=sectd5282>Conditions on references</A></H4>
1.1 cvs 6815:
6816: <P>
6817: References may be taken into account in conditions, which can be based on the
6818: fact that the element, or one of its ancestors (unless symbol <TT>*</TT> is
6819: present), is designated by a at least one reference (<TT>Referred</TT>) or by
6820: none (<TT>NOT Referred</TT>). If the element or attribute to which the
6821: condition is attached is a reference, the condition can be based on the fact
6822: that it acts as the first reference to the designated element
6823: (<TT>FirstRef</TT>), or as the last (<TT>LastRef</TT>), or as a reference to
6824: an element located in another document (<TT>ExternalRef</TT>). Like all
6825: conditions, conditions on references can be inverted by the <TT>NOT</TT>
6826: keyword.</P>
6827: </DIV>
6828:
6829: <DIV class="subsubsection">
1.6 cvs 6830: <H4><A name=sectd5283>Conditions on the parameters</A></H4>
1.1 cvs 6831:
6832: <P>
1.6 cvs 6833: Elements which are <A href="#sectc326">parameters</A> can be given a particular
1.1 cvs 6834: condition which is based on whether or not the parameter is given a value in
6835: the document (<TT>Defined</TT> or <TT>NOT Defined</TT>, respectively).</P>
6836: </DIV>
6837:
6838: <DIV class="subsubsection">
1.6 cvs 6839: <H4><A name=sectd5284>Conditions on the alphabets</A></H4>
1.1 cvs 6840:
6841: <P>
6842: The character string base type (and only this type) can use the condition
6843: <TT>Alphabet = a</TT> which indicates that the translation rule(s) should only
6844: apply if the alphabet of the character string is the one whose name appears
6845: after the equals sign (or is not, if there is a preceding <TT>NOT</TT>
6846: keyword). This condition cannot be applied to translation rules of an
6847: attribute.</P>
6848: <P>
6849: In the current implementation of Thot, the available alphabets are the
6850: <TT>Latin</TT> alphabet and the <TT>Greek</TT> alphabet.</P>
6851: </DIV>
6852:
6853: <DIV class="subsubsection">
1.6 cvs 6854: <H4><A name=sectd5285>Conditions on page breaks</A></H4>
1.1 cvs 6855:
6856: <P>
6857: The page break base type (and only this type) can use the following
6858: conditions: <TT>ComputedPage</TT>, <TT>StartPage</TT>, <TT>UserPage</TT>, and
6859: <TT>ReminderPage</TT>. The <TT>ComputedPage</TT> condition indicates that the
6860: translation rule(s) should apply if the page break was created automatically
6861: by Thot; the <TT>StartPage</TT> condition is true if the page break is
6862: generated before the element by the <TT>Page</TT> rule of the P language; the
6863: <TT>UserPage</TT> condition applies if the page break was inserted by the
6864: user; and the <TT>ReminderPage</TT> is applied if the page break is a reminder
6865: of page breaking.</P>
6866: </DIV>
6867:
6868: <DIV class="subsubsection">
1.6 cvs 6869: <H4><A name=sectd5286>Conditions on the element's content</A></H4>
1.1 cvs 6870:
6871: <P>
6872: The condition can be based on whether or not the element is empty. An element
6873: which has no children or whose leaves are all empty is considered to be empty
6874: itself. This condition is expressed by the <TT>Empty</TT> keyword, optionally
6875: preceded by the <TT>NOT</TT> keyword.</P>
6876: </DIV>
6877:
6878: <DIV class="subsubsection">
1.6 cvs 6879: <H4><A name=sectd5287>Conditions on the presence of comments</A></H4>
1.1 cvs 6880:
6881: <P>
6882: The condition can be based on the presence or absence of comments associated
6883: with the translated element. This condition is expressed by the keyword
6884: <TT>Comment</TT>, optionally preceded by the keyword <TT>NOT</TT>.</P>
6885: </DIV>
6886:
6887: <DIV class="subsubsection">
1.6 cvs 6888: <H4><A name=sectd5288>Conditions on the presence of specific presentation rules</A></H4>
1.1 cvs 6889:
6890: <P>
6891: The condition can be based on the presence or absence of specific presentation
6892: rules associated with the translated element, whatever the rules, their value
6893: or their number. This condition is expressed by the keyword
6894: <TT>Presentation</TT>, optionally preceded by the <TT>NOT</TT> keyword.</P>
6895: </DIV>
6896:
6897: <DIV class="subsubsection">
1.6 cvs 6898: <H4><A name=sectd5289>Conditions on the presence of logical attributes</A></H4>
1.1 cvs 6899:
6900: <P>
6901: In the same way, the condition can be based on the presence or absence of
6902: attributes associated with the translated elements, no matter what the
6903: attributes or their values. The <TT>Attributes</TT> keyword expresses this
6904: condition.</P>
6905: </DIV>
6906:
6907: <DIV class="subsubsection">
1.6 cvs 6908: <H4><A name=sectd52810>Conditions on logical attributes</A></H4>
1.1 cvs 6909:
6910: <P>
6911: If the condition appears in the translation rules of an attribute, the
6912: <TT>FirstAttr</TT> and <TT>LastAttr</TT> keywords can be used to indicate that
6913: the rules must only be applied if this attribute is the first attribute for
6914: the translated element or if it is the last (respectively). These conditions
6915: can also be inverted by the <TT>NOT</TT> keyword.</P>
6916: <P>
6917: Another type of condition can only be applied to the translation rules when
6918: the element being processed (or one of its ancestors if symbol <TT>*</TT> is
6919: missing) has a certain attribute, perhaps with a certain value or, in
6920: contrast, when the element does not have this attribute with this value. The
6921: condition is specified by writing the name of the attribute after the keyword
6922: <TT>IF</TT> or <TT>AND</TT>. The <TT>NOT</TT> keyword can be used to invert
6923: the condition. If the translation rules must be applied to any element which
6924: has this attribute (or does not have it, if the condition is inverted) no
6925: matter what the attribute's value, the condition is complete. If, in
6926: contrast, the condition applies to one or more values of the attribute, these
6927: are indicated after the name of the attribute, except for reference attributes
6928: which do not have values.</P>
6929: <P>
6930: The representation of the values of an <A name="relattr">attribute</A> in a
6931: condition depends on the attribute's type. For attributes with enumerated or
6932: textual types, the value (a name or character string between apostrophes,
6933: respectively) is simply preceded by an equals sign. For numeric attributes,
6934: the condition can be based on a single value or on a range of values. In the
6935: case of a unique value, this value (an integer) is simply preceded by an
6936: equals sign. Conditions based on ranges of values have several forms:</P>
6937: <UL>
1.2 cvs 6938: <LI>all values less than a given value (the value is preceded by a ``less
1.1 cvs 6939: than'' sign).
1.2 cvs 6940: <LI>all values greater than a given value (the value is preceded by a
6941: ``greater than'' sign).
6942: <LI>all values falling in an interval, bounds included. The range of values
6943: is then specified <TT>IN [</TT>Minimum <TT>..</TT>Maximum<TT>]</TT>, where
6944: Minimum and Maximum are integers.
1.1 cvs 6945: </UL>
6946: <P>
1.2 cvs 6947: All numeric values may be negative. The integer is simply preceded by a minus
1.1 cvs 6948: sign.</P>
6949: <P>
6950: Both local and global attributes can be used in conditions.</P>
6951: </DIV>
6952:
6953: <DIV class="subsubsection">
1.6 cvs 6954: <H4><A name=sectd52811>Conditions on specific presentation rules</A></H4>
1.1 cvs 6955:
6956: <P>
6957: It is possible to apply translation rules only when the element being
6958: processed has or does not have a specific presentation rule, possibly with a
6959: certain value. The condition is specified by writing the name of the
6960: presentation rule after the keyword <TT>IF</TT> or <TT>AND</TT>. The
6961: <TT>NOT</TT> keyword can be used to invert the condition. If the translation
6962: rules must be applied to any element which has this presentation rule (or does
6963: not have it, if the condition is inverted) no matter what the rule's value,
6964: the condition is complete. If, in contrast, the condition applies to one or
6965: more values of the rule, these are indicated after the name of the
6966: attribute.</P>
6967: <P>
6968: The representation of presentation rule values in a condition is similar to
6969: that for attribute values. The representation of these values depend on the
6970: type of the presentation rule. There are three categories of presentation
6971: rules:</P>
6972: <UL>
6973: <LI>those taking numeric values (<TT>Size, Indent, LineSpacing,
6974: LineWeight</TT>),
6975: <LI>those with values taken from a predefined list (<TT>Adjust, Justify,
6976: Hyphenate, Style, Font, UnderLine, Thickness, LineStyle</TT>),
6977: <LI>those whose value is a name (<TT>FillPattern, Background,
6978: Foreground</TT>).
6979: </UL>
6980: <P>
6981: For presentation rules which take numeric values, the condition can take a
6982: unique value or a range of values. In the case of a unique value, this value
6983: (an integer) is simply preceded by an equals sign. Conditions based on ranges
6984: of values have several forms:</P>
6985: <UL>
1.2 cvs 6986: <LI>all values less than a given value (the value is preceded by a ``less
1.1 cvs 6987: than'' sign).
1.2 cvs 6988: <LI>all values greater than a given value (the value is preceded by a
6989: ``greater than'' sign).
6990: <LI>all values falling in an interval, bounds included. The range of values
6991: is then specified <TT>IN [</TT>Minimum <TT>..</TT>Maximum<TT>]</TT>, where
6992: Minimum and Maximum are integers.
1.1 cvs 6993: </UL>
6994: <P>
1.2 cvs 6995: Values for the <TT>Indent</TT>rule may be negative. The integer is then
6996: simply preceded by a minus sign and represents how far the first line starts
6997: to the left of the other lines.</P>
1.1 cvs 6998: <P>
6999: For presentation rules whose values are taken from predefined lists, the value
7000: which satisfies the condition is indicated by an equals sign followed by the
7001: name of the value.</P>
7002: <P>
7003: For presentation rule whose values are names, the value which satisfies the
7004: condition is indicated by the equals sign followed by the value's name. The
7005: names of fill patterns (the <TT>FillPattern</TT> rule) and of colors (the
7006: <TT>Foreground</TT> and <TT>Background</TT> rules) known to Thot are the same
7007: as in the P language.</P>
7008: <P>
7009: The syntax of conditions based on the specific presentation is the same as the
1.6 cvs 7010: syntax used to express the <A href="#sectc5224">translation of specific
1.1 cvs 7011: presentation rules</A>.</P>
7012: <P>
7013: When a condition has only one rule, the condition is simply followed by that
7014: rule. If it has several rules, they are placed after the condition between
7015: the keywords <TT>BEGIN</TT> and <TT>END</TT>.</P>
7016: <PRE>
7017: ConditionSeq = Condition [ 'AND' Condition ] .
7018: Condition = [ 'NOT' ] [ 'Target' ] Cond .
7019: Cond = CondElem / CondAscend .
7020: CondElem ='FirstRef' / 'LastRef' /
7021: 'ExternalRef' /
7022: 'Defined' /
7023: 'Alphabet' '=' Alphabet /
7024: 'ComputedPage' / 'StartPage' /
7025: 'UserPage' / 'ReminderPage' /
7026: 'Empty' /
1.11 cvs 7027: ElemID /
1.1 cvs 7028: 'FirstAttr' / 'LastAttr' .
7029: CondAscend = [ Ascend ] CondOnAscend .
7030: Ascend = '*' / 'Parent' / 'Ancestor' LevelOrType .
7031: LevelOrType = CondRelLevel / ElemID [ ExtStruct ] .
7032: CondRelLevel = NUMBER .
7033: CondOnAscend ='First' / 'Last' /
7034: 'Referred' /
7035: [ 'Immediately' ] 'Within' [ NumParent ]
7036: ElemID [ ExtStruct ] /
7037: 'Attributes' /
7038: AttrID [ RelatAttr ] /
7039: 'Presentation' /
7040: PresRule /
7041: 'Comment' .
7042: NumParent = [ GreaterLess ] NParent .
7043: GreaterLess = '>' / '<' .
7044: NParent = NUMBER.
7045: ExtStruct = '(' ElemID ')' .
7046: Alphabet = NAME .
7047: RelatAttr ='=' Value /
7048: '>' [ '-' ] Minimum /
7049: '<' [ '-' ] Maximum /
7050: 'IN' '[' [ '-' ] MinInterval '..'
7051: [ '-' ] MaxInterval ']' .
7052: Value = [ '-' ] IntegerVal / TextVal / AttrValue .
7053: Minimum = NUMBER .
7054: Maximum = NUMBER .
7055: MinInterval = NUMBER .
7056: MaxInterval = NUMBER .
7057: IntegerVal = NUMBER .
7058: TextVal = STRING .
7059: AttrValue = NAME .
7060: </PRE>
7061: <BLOCKQUOTE class="example">
7062: <P>
7063: <STRONG>Example:</STRONG></P>
7064: <P>
1.3 cvs 7065: Suppose that after each element of type Section_Title it is useful to produce
7066: the text <TT>\label{SectX}</TT> where <TT>X</TT> represents the section number,
7067: but only if the section is designated by one or more references in the
7068: document. The following conditional rule produces this effect:</P>
1.1 cvs 7069: <PRE>
7070: RULES
7071: Section_Title :
7072: IF Referred
1.5 cvs 7073: Create ('\label{Sect' Value(UniqueSectNum) '}\12') After;
1.1 cvs 7074: </PRE>
7075: <P>
1.6 cvs 7076: (the declaration of the <A href="#sectc5224"><TT>UniqueSectNum</TT>
1.3 cvs 7077: counter</A> is given above). The string <TT>\12</TT> represents a line
1.1 cvs 7078: break.</P>
7079: </BLOCKQUOTE>
7080: <BLOCKQUOTE class="example">
7081: <P>
7082: <STRONG>Example:</STRONG></P>
7083: <P>
1.3 cvs 7084: Suppose that for elements of the Elmnt type it would be useful to produce a
7085: character indicating the value of the numeric attribute Level associated with
7086: the element: an ``A'' for all values of Level less than 3, a ``B'' for values
7087: between 3 and 10 and a ``C'' for values greater than 10. This can be achieved
7088: by writing the following rules for the Elmnt type:</P>
1.1 cvs 7089: <PRE>
7090: RULES
7091: Elmnt :
7092: BEGIN
7093: IF Level < 3
7094: Create 'A';
7095: IF Level IN [3..10]
7096: Create 'B';
7097: IF Level > 10
7098: Create 'C';
7099: END;
7100: </PRE>
7101: </BLOCKQUOTE>
7102: </DIV>
7103: </DIV>
7104:
7105: <DIV class="subsection">
1.6 cvs 7106: <H3><A name=sectc529>Translation rules</A></H3>
1.1 cvs 7107:
7108: <P>
1.10 cvs 7109: Fourteen types of translation rules can be associated with element types and
1.1 cvs 7110: attribute values. They are the <TT>Create</TT>, <TT>Write</TT>,
7111: <TT>Read</TT>, <TT>Include</TT>, <TT>Get</TT>, <TT>Copy</TT>, <TT>Use</TT>,
7112: <TT>Remove</TT>, <TT>NoTranslation</TT>, <TT>NoLineBreak</TT>,
1.10 cvs 7113: <TT>ChangeMainFile</TT>, <TT>Set</TT>, <TT>Add</TT>, <TT>Indent</TT> rules.
7114: Each rule has its own syntax, although they are all based on very similar
7115: models.</P>
1.1 cvs 7116: <PRE>
7117: SimpleRule = 'Create' [ 'IN' VarID ] Object
7118: [ Position ] ';' /
7119: 'Write' Object [ Position ] ';' /
7120: 'Read' BufferID [ Position ] ';' /
7121: 'Include' File [ Position ] ';' /
7122: 'Get' [ RelPosition ] ElemID
7123: [ ExtStruct ]
7124: [ Position ] ';' /
7125: 'Copy' [ RelPosition ] ElemID
7126: [ ExtStruct ]
7127: [ Position ] ';' /
7128: 'Use' TrSchema [ 'For' ElemID ] ';' /
7129: 'Remove' ';' /
7130: 'NoTranslation' ';' /
7131: 'NoLineBreak' ';' /
7132: 'ChangeMainFile' VarID [ Position ] ';' /
1.10 cvs 7133: 'Set' CounterID InitValue [ Position ] ';' /
7134: 'Add' CounterID Increment [ Position ] ';' /
7135: 'Indent' [ 'IN' VarID ] [ IndentSign ]
7136: IndentValue [ Position ] ';' .
1.1 cvs 7137: </PRE>
7138: </DIV>
7139:
7140: <DIV class="subsection">
1.6 cvs 7141: <H3><A name=sectc5210>The <TT>Create</TT> rule</A></H3>
1.1 cvs 7142:
7143: <P>
7144: The most frequently used rule is undoubtedly the <TT>Create</TT> rule, which
7145: generates fixed or variable text (called an <EM>object</EM>) in the output
7146: file. The generated text can be made to appear either before or after the
7147: content of the element to which the rule applies. The rule begins with the
7148: <TT>Create</TT> keyword, followed by a specifier for the object and a keyword
7149: (<TT>Before</TT> or <TT>After</TT>) indicating the position of the generated
1.6 cvs 7150: text (<A href="#sectc5222">before or after</A> the element's content). If the
1.1 cvs 7151: position is not indicated, the object will be generated before the element's
7152: content. This rule, like all translation rules, is terminated by a
7153: semicolon.</P>
7154: <P>
7155: The <TT>Create</TT> keyword can be followed by the <TT>IN</TT> keyword and by
7156: the name of a variable. This means that the text generated by the rule must
7157: not be written in the main output file, but in the file whose name is
7158: specified by the variable.</P>
7159: <P>
7160: This allows the translation program to generate text in different files during
7161: the same run. These files do not need to be explicetely declared or opened.
7162: They do not need to be closed either. As soon as the translation program
7163: executes a <TT>Create</TT> rule for a file that is not yet open, it opens the
7164: file. These files are closed when the translation is finished.</P>
7165: <PRE>
7166: 'Create' [ 'IN' VarID ] Object
7167: [ Position ] ';'
7168: Object = ConstID / CharString /
7169: BufferID /
7170: VarID /
7171: '(' Function < Function > ')' /
7172: AttrID /
7173: 'Value' /
7174: 'Content' /
7175: 'Comment' /
7176: 'Attributes' /
7177: 'Presentation' /
7178: 'RefId' /
7179: 'PairId' /
7180: 'FileDir' /
7181: 'FileName' /
7182: 'Extension' /
7183: 'DocumentName' /
7184: 'DocumentDir' /
7185: [ 'Referred' ] ReferredObject .
7186: Position ='After' / 'Before' .
7187:
7188: ReferredObject = VarID /
7189: ElemID [ ExtStruct ] /
7190: 'RefId' /
7191: 'DocumentName' /
7192: 'DocumentDir' .
7193: </PRE>
7194: <P>
7195: The object to be generated can be:</P>
7196: <UL>
1.2 cvs 7197: <LI>a constant string, specified by its name if it is declared in the schema's
1.5 cvs 7198: <TT>CONST</TT> section, or given directly as a value between apostrophes;
1.1 cvs 7199: <LI>the contents of a buffer, designated by the name of the buffer;
1.2 cvs 7200: <LI>a variable, designated by its name if it is declared in the translation
1.5 cvs 7201: schema's <TT>VAR</TT> section, or given directly between parentheses. The text
1.2 cvs 7202: generated is the value of that variable evaluated for the element to which the
1.1 cvs 7203: rule applies.
1.2 cvs 7204: <LI>the value of an attribute, if the element being translated has this
7205: attribute. The attribute is specified by its name;
7206: <LI>the value of a specific presentation rule. This object can only be
1.1 cvs 7207: generated if the translation rule is for a <A href="#prestransl">specific
1.2 cvs 7208: presentation rule</A>. It is specified by the <TT>Value</TT> keyword;
7209: <LI>the element's content. That is, the content of the leaves of the subtree
7210: of the translated element. This is specified by the <TT>Content</TT> keyword;
7211: <LI>the comment attached to the element. When the element doesn't have a
7212: comment, nothing is generated. This is indicated by the <TT>Comment</TT>
7213: keyword;
7214: <LI>the translation of all attributes of the element (which is primarily used
1.6 cvs 7215: to apply the attribute translation rules <A href="#sectc5222">before</A> those of
1.2 cvs 7216: the element type). This is specified by the <TT>Attributes</TT> keyword.
7217: <LI>the translation of all of the element's specific presentation rules (which
7218: is primarily used to apply the translation rules for the specific presentation
1.6 cvs 7219: rules <A href="#sectc5222">before</A> those of the element or its attributes).
1.2 cvs 7220: This option is specified by the <TT>Presentation</TT> keyword;
1.5 cvs 7221: <LI>The value of the reference's identifier.<BR>Thot associates a unique
1.2 cvs 7222: identifier with each element in a document. This identifier (called
7223: <EM>reference's identifier</EM> or <EM>label</EM>) is a character string
7224: containing the letter `L' followed by digits. Thot uses it in references for
7225: identifying the referred element.<BR>The <TT>RefId</TT> keyword produces the
7226: reference's identifier of the element to which the translation rule is
7227: applied, or the reference's identifier of its first ancestor that is referred
7228: by a reference or that can be referred by a reference.
7229: <LI>the value of a mark pair's unique identifier. This may only be used for
1.6 cvs 7230: <A href="#sectd3285">mark pairs</A> and is indicated by the <TT>PairId</TT>
1.2 cvs 7231: keyword.
7232: <LI>the directory containing the file being generated (this string includes an
7233: ending '/', if it is not empty). This is indicated by the <TT>FileDir</TT>
7234: keyword.
7235: <LI>the name of the file being generated (only the name, without the directory
7236: and without the extension). This is indicated by the <TT>FileName</TT>
7237: keyword.
7238: <LI>the extension of the file being generated (this string starts with a dot,
7239: if it is not empty). This is indicated by the <TT>Extension</TT> keyword.
7240: <LI>the name of the document being translated. This is indicated by the
7241: <TT>DocumentName</TT> keyword.
7242: <LI>the directory containing the document being translated. This is indicated
7243: by the <TT>DocumentDir</TT> keyword.
1.1 cvs 7244: </UL>
7245: <P>
7246: When the rule applies to a reference (an element or an attribute defined as a
7247: reference in the structure schema), it can generate a text related to the
7248: element referred by that reference. The rule name is then followed the
7249: <TT>Referred</TT> keyword and a specification of the object to be generated
7250: for the referred element. This specification can be:</P>
7251: <UL>
1.2 cvs 7252: <LI>the name of a variable. The rule generates the value of that variable,
1.1 cvs 7253: computed for the referred element.
1.2 cvs 7254: <LI>an element type. The rule generates the translation of the element of
7255: that type, which is in the subtree of the referred element. If this element
7256: is not defined in the structure schema which corresponds to the translation
7257: schema (that is, an object defined in another schema), the element's type name
7258: must be followed by the name of its structure schema between parentheses.
7259: <LI>the <TT>RefId</TT> keyword. The rule generates the reference's identifier
1.1 cvs 7260: of the referred element.
1.2 cvs 7261: <LI>the <TT>DocumentName</TT> keyword. The rule generates the name of the
1.1 cvs 7262: document to which the referred element belongs.
1.2 cvs 7263: <LI>the <TT>DocumentDir</TT> keyword. The rule generates the name of the
1.1 cvs 7264: directory that contains the document of the referred element.
7265: </UL>
7266: </DIV>
7267:
7268: <DIV class="subsection">
1.6 cvs 7269: <H3><A name=sectc5211>The <TT>Write</TT> rule</A></H3>
1.1 cvs 7270:
7271: <P>
7272: The <TT>Write</TT> has the same syntax as the <TT>Create</TT> rule. It also
7273: produces the same effect, but the generated text is displayed on the user's
7274: terminal during the translation of the document, instead of being produced in
7275: the translated document. This is useful for helping the user keep track of
7276: the progress of the translation and for prompting the user on the terminal for
7277: input required by the <TT>Read</TT> rule.</P>
7278: <PRE>
7279: 'Write' Object [ Position ] ';'
7280: </PRE>
7281: <P>
7282: Notice: if the translator is launched by the editor (by the ``Save as''
7283: command), messages produced by the <TT>Write</TT> rule are not displayed.</P>
7284: <BLOCKQUOTE class="example">
7285: <P>
7286: <STRONG>Example:</STRONG></P>
7287: <P>
1.3 cvs 7288: To make the translator display the number of each section being translated on
7289: the user's terminal, the following rule is specified for the
7290: <TT>Section</TT> element type:</P>
1.1 cvs 7291: <PRE>
7292: Section : BEGIN
7293: Write VarSection;
7294: ...
7295: END;
7296: </PRE>
7297: <P>
1.3 cvs 7298: (see <A href="#varsectexample">above</A> for the definition of
7299: the <TT>VarSection</TT> variable).</P>
1.1 cvs 7300: <P>
7301: To display text on the terminal before issuing a read operation with the
7302: <TT>Read</TT> rule, the following rule is used:</P>
7303: <PRE>
7304: BEGIN
7305: Write 'Enter the name of the destination: ';
7306: ...
7307: END;
7308: </PRE>
7309: </BLOCKQUOTE>
7310: </DIV>
7311:
7312: <DIV class="subsection">
1.6 cvs 7313: <H3><A name=sectc5212>The <TT>Read</TT> rule</A></H3>
1.1 cvs 7314:
7315: <P>
7316: The <TT>Read</TT> rule reads text from the terminal during the translation of
7317: the document and saves the text read in one of the buffers declared in the
7318: <TT>BUFFERS</TT> section of the schema. The buffer to be used is indicated by
7319: its name, after the <TT>READ</TT> keyword. This name can be followed, as in
7320: the <TT>Create</TT> and <TT>Write</TT> rules, by a keyword indicating if the
7321: read operation must be performed <TT>Before</TT> or <TT>After</TT> the
7322: translation of the element's content. If this keyword is absent, the read
7323: operation is done beforehand. The text is read into the buffer and remains
1.5 cvs 7324: there until a rule using the same buffer - possibly the same rule - is
1.1 cvs 7325: applied.</P>
7326: <PRE>
7327: 'Read' BufferID [ Position ] ';'
7328: </PRE>
7329: <BLOCKQUOTE class="example">
7330: <P>
7331: <STRONG>Example:</STRONG></P>
7332: <P>
1.3 cvs 7333: The following set of rules tells the user that the translator is waiting for
7334: the entry of some text, reads this text into a buffer and copies the text into
1.1 cvs 7335: the translated document.</P>
7336: <PRE>
7337: BEGIN
7338: Write 'Enter the name of the destination: ';
7339: Read DestName;
7340: Create DestName;
7341: ...
7342: END;
7343: </PRE>
7344: <P>
1.5 cvs 7345: (see <A href="#destname">above</A> the definition of <TT>DestName</TT>).</P>
1.1 cvs 7346: </BLOCKQUOTE>
7347: </DIV>
7348:
7349: <DIV class="subsection">
1.6 cvs 7350: <H3><A name=sectc5213>The <TT>Include</TT> rule</A></H3>
1.1 cvs 7351:
7352: <P>
7353: The <TT>Include</TT> rule, like the <TT>Create</TT> rule, is used to produce
7354: text in the translated document. It inserts constant text which is not
7355: defined in the translation schema, but is instead taken from a file. The
7356: file's name is specified after the <TT>Include</TT> keyword, either directly
7357: as a character string between apostrophes or as the name of one of the buffers
7358: declared in the <TT>BUFFERS</TT> section of the schema. In the latter case,
7359: the buffer is assumed to contain the file's name. This can be used when the
7360: included file's name is known only at the moment of translation. This only
7361: requires that the <TT>Include</TT> rule is preceded by a <TT>Read</TT> rule
7362: which puts the name of the file desired by the user into the buffer.</P>
7363: <P>
7364: Like the other rules, it is possible to specify whether the inclusion will
7365: occur before or after the element's content, with the default being before.
7366: The file inclusion is only done at the moment of translation, not during the
7367: compilation of the translation schema. Thus, the file to be included need not
7368: exist during the compilation, but it must be accessible at the time of
7369: translation. Its contents can also be modified between two translations, thus
7370: producing different results, even if neither the document or the translation
7371: schema are modified.</P>
7372: <P>
7373: During translation, the file to be included is searched for along the schema
7374: directory path (indicated by the environment variable <TT>THOTSCH</TT>). The
7375: file name is normally only composed of a simple name, without specification of
1.12 ! cvs 7376: a complete file path. However, if the filename starts with a '/', it is
! 7377: considered as an absolute path.</P>
1.1 cvs 7378: <PRE>
1.6 cvs 7379: 'Include' File [ Position ] ';'
7380: File = FileName / BufferID .
7381: FileName = STRING .
1.1 cvs 7382: </PRE>
7383: <BLOCKQUOTE class="example">
7384: <P>
7385: <STRONG>Example:</STRONG></P>
7386: <P>
1.3 cvs 7387: Suppose that it is desirable to print documents of the Article class with a
7388: formatter which requires a number of declarations and definitions at the
7389: beginning of the file. The <TT>Include</TT>rule can be used to achieve this.
7390: All the declarations and definitions a replaced in a file called
7391: <TT>DeclarArt</TT> and then the <TT>Article</TT> element type is given the
1.1 cvs 7392: following rule:</P>
7393: <PRE>
7394: Article : BEGIN
7395: Include 'DeclarArt' Before;
7396: ...
7397: END;
7398: </PRE>
7399: </BLOCKQUOTE>
7400: </DIV>
7401:
7402: <DIV class="subsection">
1.6 cvs 7403: <H3><A name=sectc5214>The <TT>Get</TT> rule</A></H3>
1.1 cvs 7404:
7405: <P>
7406: The <TT>Get</TT> rule is used to change the order in which the elements appear
7407: in the translated document. More precisely, it produces the translation of a
7408: specified element before or after the translation of the content of the
7409: element to which the rule applies. The <TT>Before</TT> and <TT>After</TT>
7410: keywords are placed at the end of the rule to specify whether the operation
7411: should be performed before or after translation of the rule's element (the
7412: default is before). The type of the element to be moved must be specified
7413: after the <TT>Get</TT> keyword, optionally preceded by a keyword indicating
7414: where the element will be found in the logical structure of the document:</P>
7415: <DL>
7416: <DT><TT>Included</TT></DT>
1.2 cvs 7417: <DD>The element to be moved is the first element of the indicated type which is
1.1 cvs 7418: found inside the element to which the rule applies.
7419: </DD>
7420: <DT><TT>Referred</TT></DT>
1.2 cvs 7421: <DD>This keyword can only be used if the rule applies to a reference element.
7422: The element to be moved is either the element designated by the reference (if
7423: that element is of the specified type), or the first element of the desired
7424: type contained within the element designated by the reference.
1.1 cvs 7425: </DD>
7426: <DT>no keyword</DT>
1.2 cvs 7427: <DD>If the element to be moved is an associated element, defined in the <A
1.6 cvs 7428: href="#sectc314"><TT>ASSOC</TT> section</A> of the structure schema, all
1.2 cvs 7429: associated elements of this type which have not been translated yet are then
7430: translated. Certain elements may in fact have already been translated by a
7431: <TT>Get Referred</TT> rule.
1.1 cvs 7432: <P>
7433: If the element to be moved is not an associated element, the translator takes
7434: the first element of the indicated type from among the siblings of the rule's
7435: element. This is primarily used to change the order of the components of an
7436: aggregate.</P>
7437: </DD>
7438: </DL>
7439: <P>
7440: If the element to be moved is defined in a structure schema which is not the
7441: one which corresponds to the translation schema (in the case of an included
7442: object with a different schema), the type name of this element must be
7443: followed, between parentheses, by the name of the structure schema which
7444: defines it.</P>
7445: <PRE>
1.6 cvs 7446: 'Get' [ RelPosition ] ElemID
7447: [ ExtStruct ]
7448: [ Position ] ';' /
7449: RelPosition = 'Included' / 'Referred' .
1.1 cvs 7450: ExtStruct = '(' ElemID ')' .
7451: </PRE>
7452: <P>
7453: The <TT>Get</TT> rule has no effect if the element which it is supposed to
7454: move has already been translated. Thus, the element will not be duplicated.
7455: It is generally best to associate the rule with the first element which will
7456: be encountered by the translator in its traversal of the document. Suppose an
7457: aggregate has two elements <TT>A</TT> and <TT>B</TT>, with <TT>A</TT>
7458: appearing first in the logical structure. To permute these two elements, a
7459: <TT>Get B before</TT> rule should be associated with the <TT>A</TT> element
7460: type, not the inverse. Similarly, a rule of the form <TT>Get Included X
7461: After</TT>, even though syntactically correct, makes no sense since, by the
7462: time it will be applied, after the translation of the contents of the element
7463: to which it is attached, the <TT>X</TT> element will already have been
7464: translated.</P>
7465: <P>
7466: The <TT>Get</TT> rule is the only way to obtain the translation of the
7467: associated elements. In fact, the translator only traverses the primary tree
7468: of the document and thus does not translate the associated elements, except
7469: when the translation is explicitly required by a <TT>Get Referred Type</TT> or
7470: <TT>Get Type</TT> rule where <TT>Type</TT> is an associated element type.</P>
7471: <BLOCKQUOTE class="example">
7472: <P>
7473: <STRONG>Example:</STRONG></P>
7474: <P>
1.3 cvs 7475: The structure schema defined figures as associated element which are composed
7476: of some content and a caption. Moreover, it is possible to make references to
7477: figures, using elements of the <TT>RefFigure</TT> type:</P>
1.1 cvs 7478: <PRE>
7479: ...
7480: RefFigure = REFERENCE(Figure);
7481: ASSOC
1.6 cvs 7482: Figure = BEGIN
7483: Content = NATURE;
7484: Caption = Text;
7485: END;
1.1 cvs 7486: ...
7487: </PRE>
7488: <P>
1.3 cvs 7489: Suppose it would be useful to make a figure appear in the translated document
7490: at the place in the text where the first reference to the figure is made. If
7491: some figures are not referenced, then they would appear at the end of the
7492: document. Also, each figure's caption should appear before the content. The
7493: following rules in the translation schema will produce this result:</P>
1.1 cvs 7494: <PRE>
7495: Article : BEGIN
7496: ...
7497: Get Figures After;
7498: END;
7499: RefFigure : BEGIN
7500: If FirstRef Get Referred Figure;
7501: ...
7502: END;
7503: Content : BEGIN
7504: Get Caption Before;
7505: ...
7506: END;
7507: </PRE>
7508: </BLOCKQUOTE>
7509: </DIV>
7510:
7511: <DIV class="subsection">
1.6 cvs 7512: <H3><A name=sectc5215>The <TT>Copy</TT> rule</A></H3>
1.1 cvs 7513:
7514: <P>
7515: Like the <TT>Get</TT> rule, the <TT>Copy</TT> rule generates the translation
7516: of a specified element, but it acts even if the element has already been
7517: translated and it allows to copy it or to translate it later. Both rules have
7518: the same syntax.</P>
7519: <PRE>
7520: 'Copy' [ RelPosition ] ElemID
7521: [ ExtStruct ] [ Position ] ';'
7522: </PRE>
7523: </DIV>
7524:
7525: <DIV class="subsection">
1.6 cvs 7526: <H3><A name=sectc5216>The <TT>Use</TT> rule</A></H3>
1.1 cvs 7527:
7528: <P>
7529: The <TT>Use</TT> rule specifies the translation schema to be applied to
7530: objects of a certain class that are part of the document. This rule only
7531: appears in the rules for the root element of the document (the first type
7532: defined after the <TT>STRUCT</TT> keyword in the structure schema) or the
7533: rules of an element defined by an external structure (by another structure
7534: schema). Also, the <TT>Use</TT> rule cannot be conditional.</P>
7535: <P>
7536: If the rule is applied to an element defined by an external structure, the
7537: <TT>Use</TT> keyword is simply followed by the name of the translation schema
7538: to be used for element constructed according to that external structure. If
7539: the rule is applied to the document's root element, it is formed by the
7540: <TT>Use</TT> keyword followed by the translation schema's name, the
7541: <TT>For</TT> keyword and the name of the external structure to which the
7542: indicated translation schema should be applied.</P>
7543: <PRE>
7544: 'Use' TrSchema [ 'For' ElemID ] ';'
7545: TrSchema = NAME .
7546: </PRE>
7547: <P>
7548: If no <TT>Use</TT> rule defines the translation schema to be used for an
7549: external structure which appears in a document, the translator asks the user,
7550: during the translation process, which schema should be used. Thus, it is not
7551: necessary to give the translation schema a <TT>Use</TT> rule for every
7552: external structure used, especially when the choice of translation schemas is
7553: to be left to the user.</P>
7554: <P>
7555: Notice: if the translator is launched by the editor (by the ``Save as''
7556: command), prompts are not displayed.</P>
7557: <BLOCKQUOTE class="example">
7558: <P>
7559: <STRONG>Example:</STRONG></P>
7560: <P>
1.4 cvs 7561: The <TT>Article</TT> structure schema uses the
7562: <TT>Formula</TT> external structure, defined by another structure schema, for
1.1 cvs 7563: mathematical formulas:</P>
7564: <PRE>
7565: STRUCTURE Article;
7566: ...
7567: STRUCT
7568: Article = ...
7569: ...
7570: Formula_in_text = Formula;
7571: Isolated_formula = Formula;
7572: ...
7573: END
7574: </PRE>
7575: <P>
1.3 cvs 7576: Suppose that it would be useful to use the <TT>FormulaT</TT> translation schema
7577: for the formulas of an article. This can be expressed in two different ways in
1.4 cvs 7578: the <TT>Article</TT> class translation schema, using the rules:</P>
1.1 cvs 7579: <PRE>
7580: RULES
7581: Article :
7582: Use FormulaT for Formula;
7583: </PRE>
7584: <P>
7585: or:</P>
7586: <PRE>
7587: RULES
7588: ...
7589: Formula :
7590: Use FormulaT;
7591: </PRE>
7592: </BLOCKQUOTE>
7593: </DIV>
7594:
7595: <DIV class="subsection">
1.6 cvs 7596: <H3><A name=sectc5217>The <TT>Remove</TT> rule</A></H3>
1.1 cvs 7597:
7598: <P>
7599: The <TT>Remove</TT> rule indicates that nothing should be generated, in the
7600: translated document, for the content of the element to which the rule applies.
7601: The content of that element is simply ignored by the translator. This does
7602: not prevent the generation of text for the element itself, using the
7603: <TT>Create</TT> or <TT>Include</TT> rules, for example.</P>
7604: <P>
7605: The <TT>Remove</TT> rule is simply written with the <TT>Remove</TT> keyword.
7606: It is terminated, like all rules, by a semicolon.</P>
7607: <PRE>
7608: 'Remove' ';'
7609: </PRE>
7610: </DIV>
7611:
7612: <DIV class="subsection">
1.6 cvs 7613: <H3><A name=sectc5218>The <TT>NoTranslation</TT> rule</A></H3>
1.1 cvs 7614:
7615: <P>
7616: The <TT>NoTranslation</TT> rule indicates to the translator that it must not
7617: translate the content of the leaves of the element to which it applies. In
7618: contrast to the <TT>Remove</TT> rule, it does not suppress the content of the
7619: element, but it inhibits the translation of character strings, symbols, and
7620: graphical elements contained in the element. These are retrieved so that
7621: after the translation of the document, the rules of the <A
1.6 cvs 7622: href="#sectc5225"><TT>TEXTTRANSLATE</TT>, <TT>SYMBTRANSLATE</TT> and
1.1 cvs 7623: <TT>GRAPHTRANSLATE</TT> sections</A> will not be applied to them.</P>
7624: <P>
7625: The <TT>NoTranslation</TT> rule is written with the <TT>NoTranslation</TT>
7626: keyword followed by a semicolon.</P>
7627: <PRE>
7628: 'NoTranslation' ';'
7629: </PRE>
7630: </DIV>
7631:
7632: <DIV class="subsection">
1.6 cvs 7633: <H3><A name=sectc5219>The <TT>NoLineBreak</TT> rule</A></H3>
1.1 cvs 7634:
7635: <P>
7636: The <TT>NoLineBreak</TT> rule indicates to the translator that it must not
7637: generate additional line breaks in the output produced for the element to
1.6 cvs 7638: which it applies. This is as if it was an <A href="#sectc522">instruction
1.1 cvs 7639: <TT>LINELENGTH 0;</TT></A> at the beginning of the translation schema, but
7640: only for the current element.</P>
7641: <P>
7642: The <TT>NoLineBreak</TT> rule is written with the <TT>NoLineBreak</TT> keyword
7643: followed by a semicolon.</P>
7644: <PRE>
7645: 'NoLineBreak' ';'
7646: </PRE>
7647: </DIV>
7648:
7649: <DIV class="subsection">
1.6 cvs 7650: <H3><A name=sectc5220>The <TT>ChangeMainFile</TT> rule</A></H3>
1.1 cvs 7651:
7652: <P>
7653: When the translation program starts, it opens a main output file, whose name
1.6 cvs 7654: is given as a parameter of the program. All <A href="#sectc5210"><TT>Create</TT>
1.1 cvs 7655: rules</A> without explicit indication of the output file write sequentially in
7656: this file. When a <TT>ChangeMainFile</TT> rule is executed, the main output
7657: file is closed and it is replaced by a new one, whose name is specified in the
7658: <TT>ChangeMainFile</TT> rule. The <TT>Create</TT> rules without indication of
7659: the output file that are then executed write in this new file. Several
7660: <TT>ChangeMainFile</TT> rules can be executed during the same translation, for
7661: dividing the main output into several files.</P>
7662: <P>
7663: This rule is written with the <TT>ChangeMainFile</TT> keyword followed by the
7664: name of a variable that specify the name of the new main file. The keyword
7665: <TT>Before</TT> or <TT>After</TT> can be placed at the end of the rule to
7666: specify whether the operation should be performed before or after translation
7667: of the rule's element (the default is before). This rule, like all translation
7668: rules, is terminated by a semicolon.</P>
7669: <PRE>
7670: 'ChangeMainFile' VarID [ Position ] ';'
7671: </PRE>
7672: <BLOCKQUOTE class="example">
7673: <P>
7674: <STRONG>Example:</STRONG></P>
7675: <P>
1.3 cvs 7676: To generate the translation of each section in a different file, the following
7677: rule can be associated with type <TT>Section</TT>. That rule uses the <A
7678: href="#varoutputfile"><TT>VarOutpuFile</TT> variable</A> defined above.</P>
1.1 cvs 7679: <PRE>
7680: Section:
7681: ChangeMainFile VarOutpuFile Before;
7682: </PRE>
7683: <P>
1.3 cvs 7684: If <TT>output.txt</TT> is the name of the output file specified when starting
7685: the translation program, translated sections are written in files
1.1 cvs 7686: <TT>output1.txt</TT>, <TT>output2.txt</TT>, etc.</P>
7687: </BLOCKQUOTE>
7688: </DIV>
7689:
7690: <DIV class="subsection">
1.6 cvs 7691: <H3><A name=sectc5221>The <TT>Set</TT> and <TT>Add</TT> rules</A></H3>
1.1 cvs 7692:
7693: <P>
7694: The <TT>Set</TT> and <TT>Add</TT> rules are used for modifying the value of
1.6 cvs 7695: counters that have no <A href="#sectc524">counting function</A>. Only this
1.1 cvs 7696: type of counter can be used in the <TT>Set</TT> and <TT>Add</TT> rules.</P>
7697: <P>
7698: Both rules have the same syntax: after the keyword <TT>Set</TT> or
7699: <TT>Add</TT> appear the counter name and the value to assign to the counter
7700: (<TT>Set</TT> rule) or the value to be added to the counter (<TT>Add</TT>
7701: rule). The keyword <TT>Before</TT> or <TT>After</TT> can follo9w that value to
7702: indicate when the rule must be applied: before or after the element's content
7703: is translated. By default, <TT>Before</TT> is assumed. A semicolon terminates
7704: the rule.</P>
7705: <PRE>
7706: 'Set' CounterID InitValue [ Position ] ';' /
7707: 'Add' CounterID Increment [ Position ] ';'
7708: </PRE>
7709: </DIV>
7710:
7711: <DIV class="subsection">
1.10 cvs 7712: <H3><A name=sectc5221a>The <TT>Indent</TT> rule</A></H3>
7713:
7714: <P>
7715: The <TT>Indent</TT> rule is used to modify the value of text indentation
7716: in the output files.</P>
7717: <P>
7718: Each time the translator creates a new line in an output file, it generates
7719: a variable number of space characters at the beginning of the new line. By
7720: default, the number of these characters (the indentation) is 0. It can be
7721: changed with the <TT>Indent</TT> rule.</P>
7722: <P>
7723: The rule begins with the <TT>Indent</TT> keyword, followed by the indentation
7724: sign (optional) and value and a keyword <TT>Before</TT> or <TT>After</TT>
7725: indicating that the indentation should be changed <A href="#sectc5222">before
7726: or after</A> the element's content is generated. If the position is not
7727: indicated, the indentation is changed before the element's content is
7728: generated. This rule, like all translation rules, is terminated by a
7729: semicolon.</P>
7730: <P>
7731: The indentation value is indicated by an integer, which is the number of
7732: space characters to be generated at the beginning of each new line.
7733: A sign (<TT>+</TT> or <TT>-</TT>) can appear before the integer to indicate
7734: that the value is relative: the current value of indentation is incremented
7735: (if sign is <TT>+</TT>) or decremented (if sign is <TT>-</TT>) by the
7736: specified value.
7737: <P>
7738: Like the <A href="#sectc5210"><TT>Create</TT> rule</A>, the <TT>Indent</TT>
7739: keyword can be followed by the <TT>IN</TT> keyword and by the name of a
7740: <A href="#sectc526">variable</A>. This means that the rule must not change
7741: indentation in the main output file, but in the file whose name is specified
7742: by the variable (by default, indentation is changed in the main output
7743: file).</P>
7744: <PRE>
7745: 'Indent' [ 'IN' VarID ] [ IndentSign ]
7746: IndentValue [ Position ] ';' .
7747:
7748: IndentSign = '+' / '-' .
7749: IndentValue = NUMBER .
7750: </PRE>
7751: </DIV>
7752:
7753: <DIV class="subsection">
1.6 cvs 7754: <H3><A name=sectc5222>Rule application order</A></H3>
1.1 cvs 7755:
7756: <P>
7757: The translator translates the elements which comprise the document in the
7758: order induced by the tree structure, except when the <TT>Get</TT> rule is used
7759: to change the order of translation. For each element, the translator first
7760: applies the rules specified for the element's type that must be applied before
7761: translation of the element's content (rules ending with the <TT>Before</TT>
7762: keyword or which have no position keyword). If several rules meet these
7763: criteria, the translator applies them in the order in where they appear in the
7764: translation schema.</P>
7765: <P>
1.6 cvs 7766: It then applies all <A href="#sectc5223">rules for the attributes</A> which
1.1 cvs 7767: the element has and which must be applied before the translation of the
7768: element's content (rules ending with the <TT>Before</TT> keyword or which have
7769: no position keyword). For one attribute value, the translator applies the
7770: rules in the order in which they are defined in the translation schema.</P>
7771: <P>
7772: The same procedure is followed with translation rules for specific
7773: presentations.</P>
7774: <P>
7775: Next, the element's content is translated, as long as a <TT>Remove</TT> rule
7776: does not apply.</P>
7777: <P>
7778: In the next step, the translator applies rules for the specific presentation
7779: of the element that are to be applied after translation of the content (rules
7780: which end with the <TT>After</TT> keyword). The rules for each type of
7781: presentation rule or each value are applied in the order in which the
7782: translation appear in the schema.</P>
7783: <P>
7784: Then, the same procedure is followed for translation rules for attributes of
7785: the element.</P>
7786: <P>
7787: Finally, the translator applies rules for the element which must be applied
7788: after translation of the element's content. These rules are applied in the
7789: order that they appear in the translation schema. When the translation of an
7790: element is done, the translator procedes to translate the following
7791: element.</P>
7792: <P>
7793: This order can be changed with the <TT>Attributes</TT> and
1.6 cvs 7794: <TT>Presentation</TT> options of the <A href="#sectc5210"><TT>Create</TT>
1.1 cvs 7795: rule</A>.</P>
7796: </DIV>
7797:
7798: <DIV class="subsection">
1.6 cvs 7799: <H3><A name=sectc5223>Translation of logical attributes</A></H3>
1.1 cvs 7800:
7801: <P>
7802: After the rules for the element types, the translation schema defines rules
7803: for attribute values. This section begins with the <TT>ATTRIBUTES</TT>
7804: keyword and is composed of a sequence of rule blocks each preceded by an
7805: attribute name and an optional value or value range.</P>
7806: <P>
7807: If the attribute's name appears alone before the rule block, the rule are
7808: applied to all element which have the attribute, no matter what value the
7809: attribute has. In this case, the attribute name is followed by a colon before
7810: the beginning of the rule block.</P>
7811: <P>
7812: The attribute's name can be followed by the name of an element type between
7813: parentheses. This says, as in presentation schemas, that the rule block which
7814: follows applies not to the element which has the attribute, but to its
7815: descendants of the type indicated between the parentheses.</P>
7816: <P>
7817: If values are given after the attribute name (or after the name of the element
7818: type), the rules are applied only when the attribute has the indicated values.
7819: The same attribute can appear several times, with different values and
7820: different translation rules. Attribute values are indicated in the same way
1.6 cvs 7821: as in <A href="#sectc528">conditions</A> and are followed by a colon before
1.1 cvs 7822: the block of rules.</P>
7823: <P>
7824: The rule block associated with an attribute is either a simple rule or a
7825: sequence of rules delimited by the <TT>BEGIN</TT> and <TT>END</TT> keywords.
7826: Note that rules associated with attribute values cannot be conditional.</P>
7827: <P>
7828: Translation rules are not required for all attributes (or their values)
7829: defined in a structure schema. Only those attributes for which a particular
7830: action must be performed by the translator must have such rules. The rules
7831: that can be used are those described above, from <A
1.6 cvs 7832: href="#sectc5210"><TT>Create</TT></A> to <A
7833: href="#sectc5218"><TT>NoTranslation</TT></A>.</P>
1.1 cvs 7834: <PRE>
7835: AttrSeq = TransAttr < TransAttr > .
7836: TransAttr = AttrID [ '(' ElemID ')' ]
7837: [ RelatAttr ] ':' RuleSeq .
7838: AttrID = NAME .
7839: ElemID = NAME .
7840: </PRE>
7841: <BLOCKQUOTE class="example">
7842: <P>
7843: <STRONG>Example:</STRONG></P>
7844: <P>
1.3 cvs 7845: The structure defined the ``Language'' attribute which can take the values
7846: ``French'' and ``English''. To have the French parts of the original document
7847: removed and prevent the translation of the leaves of the English parts, the
1.1 cvs 7848: following rules would be used:</P>
7849: <PRE>
7850: ATTRIBUTES
7851: Language=French :
7852: Remove;
7853: Language=English :
7854: NoTranslation;
7855: </PRE>
7856: </BLOCKQUOTE>
7857: </DIV>
7858:
7859: <DIV class="subsection">
1.6 cvs 7860: <H3><A name=sectc5224>Translation of specific presentations</A></H3>
1.1 cvs 7861:
7862: <P>
7863: After the rules for attributes, the translation schema defines rules for the
7864: specific presentation. This section begins with the <TT>PRESENTATION</TT>
7865: keyword and is composed of a sequence of translation rule blocks each preceded
7866: by a presentation rule name, optionally accompanied by a part which depends on
7867: the particular presentation rule.</P>
7868: <P>
7869: Each of these translation rule blocks is applied when the translator operates
7870: on an element which has a specific presentation rule of the type indicated at
7871: the head of the block. Depending on the type of the specific presentation
7872: rule, it is possible to specify values of the presentation rule for which the
7873: translation rule block should be applied.</P>
7874: <P>
7875: There are three categories of the presentation rules:</P>
7876: <UL>
1.2 cvs 7877: <LI>rules taking numeric values: <TT>Size</TT>, <TT>Indent</TT>,
7878: <TT>LineSpacing</TT>, <TT>LineWeight</TT>,
7879: <LI>rules whose values are taken from a predefined list (i.e. whose type is an
1.1 cvs 7880: enumeration): <TT>Adjust</TT>, <TT>Justify</TT>, <TT>Hyphenate,/TT>,
7881: <TT>Style</TT>, <TT>Font</TT>, <TT>UnderLine</TT>, <TT>Thickness</TT>,
7882: <TT>LineStyle</TT>,</TT>
1.2 cvs 7883: <LI>rules whose value is a name: <TT>FillPattern</TT>, <TT>Background</TT>,
7884: <TT>Foreground</TT>.
1.1 cvs 7885: </UL>
7886: <P>
7887: For presentation rules of the first category, the values which provoke
7888: application of the translation rules are indicated in the same manner as for
7889: <A href="#relattr">numeric attributes</A>. This can be either a unique value
7890: or range of values. For a unique value, the value (an integer) is simply
7891: preceded by an equals sign. Value ranges can be specified in one of three
7892: ways:</P>
7893: <UL>
1.2 cvs 7894: <LI>all values less than a given value (this value is preceded by a ``less
1.5 cvs 7895: than'' sign '<TT><</TT>'),
1.2 cvs 7896: <LI>all values greater than a given value (this value is preceded by a`
1.5 cvs 7897: `greater than'' sign '<TT>></TT>'),
1.2 cvs 7898: <LI>all values falling in an interval, bounds included. The range of values
7899: is then specified <TT>IN [</TT>Minimum<TT>..</TT>Maximum<TT>]</TT>, where
7900: Minimum and Maximum are integers.
1.1 cvs 7901: </UL>
7902: <P>
1.2 cvs 7903: All numeric values can be negative, in which case the integer is preceded by a
7904: minus sign. All values must be given in typographers points.</P>
1.1 cvs 7905: <P>
7906: For presentation rules whose values are taken from a predefined list, the
7907: value which provokes application of the translation rules is simply indicated
7908: by the equals sign followed by the name of the value.</P>
7909: <P>
7910: For presentation rules whose values are names, the value which provokes the
7911: application of translation rules is simply indicated by the equals sign
7912: followed by the name of the value. The names of the fill patterns (the
7913: <TT>FillPattern</TT> rule) and of the colors (the <TT>Foreground</TT> and
7914: <TT>Background</TT> rules) used in Thot are the same as in the P language.</P>
7915: <PRE>
7916: PresSeq = PresTrans < PresTrans > .
7917: PresTrans = PresRule ':' RuleSeq .
7918: PresRule = 'Size' [ PresRelation ] /
7919: 'Indent' [ PresRelation ] /
7920: 'LineSpacing' [ PresRelation ] /
7921: 'Adjust' [ '=' AdjustVal ] /
7922: 'Justify' [ '=' BoolVal ] /
7923: 'Hyphenate' [ '=' BoolVal ] /
7924: 'Style' [ '=' StyleVal ] /
7925: 'Font' [ '=' FontVal ] /
7926: 'UnderLine' [ '=' UnderLineVal ] /
7927: 'Thickness' [ '=' ThicknessVal ] /
7928: 'LineStyle' [ '=' LineStyleVal ] /
7929: 'LineWeight' [ PresRelation ] /
7930: 'FillPattern' [ '=' Pattern ] /
7931: 'Background' [ '=' Color ] /
7932: 'Foreground' [ '=' Color ] .
7933:
7934: PresRelation = '=' PresValue /
7935: '>' [ '-' ] PresMinimum /
7936: '<' [ '-' ] PresMaximum /
7937: 'IN' '[' [ '-' ] PresIntervalMin '..'
7938: [ '-' ] PresIntervalMax ']' .
7939: AdjustVal = 'Left' / 'Right' / 'VMiddle' /
7940: 'LeftWithDots' .
7941: BoolVal = 'Yes' / 'No' .
7942: StyleVal = 'Bold' / 'Italics' / 'Roman' /
7943: 'BoldItalics' / 'Oblique' /
7944: 'BoldOblique' .
7945: FontVal = 'Times' / 'Helvetica' / 'Courier' .
7946: UnderLineVal = 'NoUnderline' / 'UnderLined' /
7947: 'OverLined' / 'CrossedOut' .
7948: ThicknessVal = 'Thick' / 'Thin' .
1.6 cvs 7949: LineStyleVal = 'Solid' / 'Dashed' / 'Dotted' .
1.1 cvs 7950: Pattern = NAME .
7951: Color = NAME .
7952: PresMinimum = NUMBER .
7953: PresMaximum = NUMBER .
7954: PresIntervalMin= NUMBER .
7955: PresIntervalMax= NUMBER .
7956: PresValue = [ '-' ] PresVal .
7957: PresVal = NUMBER .
7958: </PRE>
7959: <P>
7960: The <A name="prestransl">translation rules associated with specific
7961: presentation rules</A> can use the value of the specific presentation rule
7962: that causes them to be applied. This behavior is designated by the keyword
7963: <TT>Value</TT>. For numerically-valued presentation rules, the numeric value
7964: is produced. For other presentation rules, the name of the value is
7965: produced.</P>
7966: <P>
7967: It should be noted that modifications to the layout of the document's elements
7968: that are made using the combination of the control key and a mouse button will
7969: have no effect on the translation of the document.</P>
7970: <BLOCKQUOTE class="example">
7971: <P>
7972: <STRONG>Example:</STRONG></P>
7973: <P>
1.3 cvs 7974: Suppose that it is desirable to use the same font sizes as in the specific
7975: presentation, but the font size must be between 10 and 18 typographer's points.
7976: If font size is set in the translated document by the string
7977: <TT>pointsize=n</TT> where <TT>n</TT> is the font size in typographer's points
1.1 cvs 7978: then the following rules will suffice:</P>
7979: <PRE>
7980: PRESENTATION
7981: Size < 10 :
7982: Create 'pointsize=10';
7983: Size in [10..18] :
7984: BEGIN
7985: Create 'pointsize=';
7986: Create Value;
7987: END;
7988: Size > 18 :
7989: Create 'pointsize=18';
7990: </PRE>
7991: </BLOCKQUOTE>
7992: </DIV>
7993:
7994: <DIV class="subsection">
1.6 cvs 7995: <H3><A name=sectc5225>Recoding of characters, symbols and graphics</A></H3>
1.1 cvs 7996:
7997: <P>
7998: The coding of characters, graphical elements and symbols as defined in Thot
7999: does not necessarily correspond to what is required by an application to which
8000: a Thot document must be exported. Because of this the translator can recode
8001: these terminal elements of the documents structure. The last sections of a
8002: translation schema are intended for this purpose, each specifying the recoding
8003: rules for one type of terminal element.</P>
8004: <P>
8005: The recoding rules for character strings are grouped by alphabets. There is a
8006: group of rules for each alphabet of the Thot document that must be translated.
8007: Each such group of rules begins with the <TT>TEXTTRANSLATE</TT> keyword,
8008: followed by the specification of the alphabet to translate and the recoding
8009: rules, between the <TT>BEGIN</TT> and <TT>END</TT> keywords unless there is
8010: only one recoding rule for the alphabet. The specification of the alphabet is
8011: not required: by default it is assumed to the Latin alphabet (the ISO Latin-1
8012: character set).</P>
8013: <P>
8014: Each recoding rule is formed by a source string between apostrophes and a
8015: target string, also between apostrophes, the two strings being separated by
8016: the arrow symbol (<TT>-></TT>), formed by the ``minus'' and ``greater than''
8017: characters. The rule is terminated by a semi-colon.</P>
8018: <PRE>
8019: TextTransSeq = [ Alphabet ] TransSeq .
8020: Alphabet = NAME .
8021: TransSeq ='BEGIN' < Translation > 'END' ';' /
8022: Translation .
8023: Translation = Source [ '->' Target ] ';' .
8024: Source = STRING .
8025: Target = STRING .
8026: </PRE>
8027: <P>
8028: One such rule signifies that when the source string appears in a text leaf of
8029: the document being translated, the translator must replace it, in the
8030: translated document, with the target string. The source string and the target
8031: string can have different lengths and the target string can be empty. In this
8032: last case, the translator simply suppresses every occurrence of the source
8033: string in the translated document.</P>
8034: <P>
8035: For a given alphabet, the order of the rules is not important and has no
8036: significance because the T language compiler reorders the rules in ways that
8037: speed up the translator's work. The total number of recoding rules is limited
8038: by the compiler as is the maximum length of the source and target strings.</P>
8039: <P>
8040: The recoding rules for symbols and graphical elements are written in the same
8041: manner as the recoding rules for character strings. They are preceded,
8042: respectively, by the <TT>SYMBTRANSLATE</TT> and <TT>GRAPHTRANSLATE</TT> and so
8043: not require a specification of the alphabet. Their source string is limited to
8044: one character, since, in Thot, each symbol and each graphical element is
8045: represented by a single character. The symbol and graphical element codes are
1.6 cvs 8046: defined along with the <A href="#sect7">non-standard character
1.1 cvs 8047: codes</A>.</P>
8048: <BLOCKQUOTE class="example">
8049: <P>
8050: <STRONG>Example:</STRONG></P>
8051: <P>
8052: In a translation schema producing documents destined for use with
1.3 cvs 8053: the L<SUP>A</SUP>T<SUB><BIG>E</BIG></SUB>X formatter, the Latin
1.1 cvs 8054: characters``é'' (octal code 351 in Thot) and ``è'' (octal code
1.3 cvs 8055: 350 in Thot) must be converted to their representation
8056: in L<SUP>A</SUP>T<SUB><BIG>E</BIG></SUB>X:</P>
1.1 cvs 8057: <PRE>
1.6 cvs 8058: TEXTTRANSLATE Latin
1.1 cvs 8059: BEGIN
8060: '\350' -> '\`{e}'; { e grave }
8061: '\351' -> '\''{e}'; { e acute }
8062: END;
8063: </PRE>
8064: </BLOCKQUOTE>
8065: </DIV>
8066: </DIV>
8067: <HR>
8068: </DIV>
8069:
8070: <DIV class="chapter">
1.6 cvs 8071: <H1><A name=sect6>Language grammars</A></H1>
1.1 cvs 8072:
8073: <P>
8074: This chapter gives the complete grammars of the languages of Thot. The
8075: grammars were presented and described in the preceding chapters, which also
8076: specify the semantics of the languages. This section gives only the
8077: syntax.</P>
8078:
8079: <DIV class="section">
1.6 cvs 8080: <H2><A name=sectb61>The M meta-language</A></H2>
1.1 cvs 8081:
8082: <P>
8083: The language grammars are all expressed in the same formalism, the M
8084: meta-language, which is defined in this section.</P>
8085: <PRE>
8086: { Any text between braces is a comment. }
8087: Grammar = Rule < Rule > 'END' .
8088: { The < and > signs indicate zero }
8089: { or more repetitions. }
8090: { END marks the end of the grammar. }
8091: Rule = Ident '=' RightPart '.' .
8092: { The period indicates the end of a rule }
8093: RightPart = RtTerminal / RtIntermed .
8094: { The slash indicates a choice }
8095: RtTerminal ='NAME' / 'STRING' / 'NUMBER' .
8096: { Right part of a terminal rule }
8097: RtIntermed = Possibility < '/' Possibility > .
8098: { Right part of an intermediate rule }
8099: Possibility = ElemOpt < ElemOpt > .
8100: ElemOpt = Element / '[' Element < Element > ']' /
8101: '<' Element < Element > '>' .
8102: { Brackets delimit optional parts }
8103: Element = Ident / KeyWord .
8104: Ident = NAME .
8105: { Identifier, sequence of characters
8106: KeyWord = STRING .
8107: { Character string delimited by apostrophes }
8108: END
8109: </PRE>
8110: </DIV>
8111:
8112: <DIV class="section">
1.6 cvs 8113: <H2><A name=sectb62>The S language</A></H2>
1.1 cvs 8114:
8115: <P>
8116: The S language is used to write structure schemas, which contain the generic
8117: logical structures of document and object classes. It is described here in
8118: the M meta-language.</P>
8119: <PRE>
8120: StructSchema = 'STRUCTURE' [ 'EXTENSION' ] ElemID ';'
8121: 'DEFPRES' PresID ';'
8122: [ 'ATTR' AttrSeq ]
8123: [ 'PARAM' RulesSeq ]
8124: [ 'STRUCT' RulesSeq ]
8125: [ 'EXTENS' ExtensRuleSeq ]
8126: [ 'ASSOC' RulesSeq ]
8127: [ 'UNITS' RulesSeq ]
8128: [ 'EXPORT' SkeletonSeq ]
8129: [ 'EXCEPT' ExceptSeq ]
8130: 'END' .
8131:
8132: ElemID = NAME .
8133: PresID = NAME .
8134:
8135: AttrSeq = Attribute < Attribute > .
8136: Attribute = AttrID '=' AttrType ';' .
8137: AttrType = 'INTEGER' / 'TEXT' /
8138: 'REFERENCE' '(' RefType ')' /
8139: ValueSeq .
8140: RefType = 'ANY' /
8141: [ FirstSec ] ElemID [ ExtStruct ] .
8142: ValueSeq = AttrVal < ',' AttrVal > .
8143: AttrID = NAME .
8144: FirstSec = 'First' / 'Second' .
8145: ExtStruct = '(' ElemID ')' .
8146: AttrVal = NAME .
8147:
8148: RulesSeq = Rule < Rule > .
8149: Rule = ElemID [ LocAttrSeq ] '='
8150: DefWithAttr ';' .
8151: LocAttrSeq = '(' 'ATTR' LocalAttr
8152: < ';' LocalAttr > ')' .
8153: LocalAttr = [ '!' ] AttrID [ '=' AttrType ] .
8154: DefWithAttr = Definition
8155: [ '+' '(' ExtensionSeq ')' ]
8156: [ '-' '(' RestrictSeq ')' ]
8157: [ 'WITH' FixedAttrSeq ] .
8158: ExtensionSeq = ExtensionElem < ',' ExtensionElem > .
8159: ExtensionElem = ElemID / 'TEXT' / 'GRAPHICS' /
8160: 'SYMBOL' / 'PICTURE' .
8161: RestrictSeq = RestrictElem < ',' RestrictElem > .
8162: RestrictElem = ElemID / 'TEXT' / 'GRAPHICS' /
8163: 'SYMBOL' / 'PICTURE' .
8164: FixedAttrSeq = FixedAttr < ',' FixedAttr > .
8165: FixedAttr = AttrID [ FixedOrModifVal ] .
8166: FixedOrModifVal= [ '?' ] '=' FixedValue .
8167: FixedValue = [ '-' ] NumValue / TextValue / AttrVal .
8168: NumValue = NUMBER .
8169: TextValue = STRING .
8170:
8171: Definition = BaseType [ LocAttrSeq ] / Constr /
8172: Element .
8173: BaseType = 'TEXT' / 'GRAPHICS' / 'SYMBOL' /
8174: 'PICTURE' / 'UNIT' / 'NATURE' .
8175: Element = ElemID [ ExtOrDef ] .
8176: ExtOrDef = 'EXTERN' / 'INCLUDED' /
8177: [ LocAttrSeq ] '=' Definition .
8178:
8179: Constr = 'LIST' [ '[' min '..' max ']' ] 'OF'
8180: '(' DefWithAttr ')' /
8181: 'BEGIN' DefOptSeq 'END' /
8182: 'AGGREGATE' DefOptSeq 'END' /
8183: 'CASE' 'OF' DefSeq 'END' /
8184: 'REFERENCE' '(' RefType ')' /
8185: 'PAIR' .
8186:
8187: min = Integer / '*' .
8188: max = Integer / '*' .
8189: Integer = NUMBER .
8190:
8191: DefOptSeq = DefOpt ';' < DefOpt ';' > .
8192: DefOpt = [ '?' ] DefWithAttr .
8193:
8194: DefSeq = DefWithAttr ';' < DefWithAttr ';' > .
8195:
8196: SkeletonSeq = SkeletonElem < ',' SkeletonElem > ';' .
8197: SkeletonElem = ElemID [ 'WITH' Contents ] .
8198: Contents = 'Nothing' / ElemID [ ExtStruct ] .
8199:
8200: ExceptSeq = Except ';' < Except ';' > .
8201: Except = [ 'EXTERN' ] [ FirstSec ] ExcTypeOrAttr ':'
8202: ExcValSeq .
8203: ExcTypeOrAttr = ElemID / AttrID .
8204: ExcValSeq = ExcValue < ',' ExcValue > .
8205: ExcValue = 'NoCut' / 'NoCreate' /
8206: 'NoHMove' / 'NoVMove' / 'NoMove' /
8207: 'NoHResize' / 'NoVResize' / 'NoResize' /
8208: 'NewWidth' / 'NewHeight' /
8209: 'NewHPos' / 'NewVPos' /
8210: 'Invisible' / 'NoSelect' /
8211: 'Hidden' / 'ActiveRef' /
8212: 'ImportLine' / 'ImportParagraph' /
1.9 cvs 8213: 'NoPaginate' / 'ParagraphBreak' /
8214: 'HighlightChildren' / 'ExtendedSelection' /
8215: 'ReturnCreateNL' .
1.1 cvs 8216:
8217: ExtensRuleSeq = ExtensRule ';' < ExtensRule ';' > .
8218: ExtensRule = RootOrElem [ LocAttrSeq ]
8219: [ '+' '(' ExtensionSeq ')' ]
8220: [ '-' '(' RestrictSeq ')' ]
8221: [ 'WITH' FixedAttrSeq ] .
8222: RootOrElem = 'Root' / ElemID .
8223:
8224: END
8225: </PRE>
8226: </DIV>
8227:
8228: <DIV class="section">
1.6 cvs 8229: <H2><A name=sectb63>The P language</A></H2>
1.1 cvs 8230:
8231: <P>
8232: The P language is used to write presentation schemas, which define the
8233: graphical presentation rules to be applied to different classes of documents
8234: and objects. It is described here in the M meta-language.</P>
8235: <PRE>
8236: PresSchema = 'PRESENTATION' ElemID ';'
8237: [ 'VIEWS' ViewSeq ]
8238: [ 'PRINT' PrintViewSeq ]
8239: [ 'COUNTERS' CounterSeq ]
8240: [ 'CONST' ConstSeq ]
8241: [ 'VAR' VarSeq ]
8242: [ 'DEFAULT' ViewRuleSeq ]
8243: [ 'BOXES' BoxSeq ]
8244: [ 'RULES' PresentSeq ]
8245: [ 'ATTRIBUTES' PresAttrSeq ]
8246: [ 'TRANSMIT' TransmitSeq ]
8247: 'END' .
8248:
8249: ElemID = NAME .
8250:
8251: ViewSeq = ViewDeclaration
8252: < ',' ViewDeclaration > ';' .
8253: ViewDeclaration = ViewID [ 'EXPORT' ] .
8254: ViewID = NAME .
8255:
8256: PrintViewSeq = PrintView < ',' PrintView > ';' .
8257: PrintView = ViewID / ElemID .
8258:
8259: CounterSeq = Counter < Counter > .
8260: Counter = CounterID ':' CounterFunc ';' .
8261: CounterID = NAME .
8262: CounterFunc = 'RANK' 'OF' TypeOrPage [ SLevelAsc ]
8263: [ 'INIT' AttrID ] [ 'REINIT' AttrID ] /
8264: SetFunction < SetFunction >
8265: AddFunction < AddFunction >
8266: [ 'INIT' AttrID ] /
8267: 'RLEVEL' 'OF' ElemID .
8268: SLevelAsc = [ '-' ] LevelAsc .
8269: LevelAsc = NUMBER .
8270: SetFunction = 'SET' CounterValue 'ON' TypeOrPage .
8271: AddFunction = 'ADD' CounterValue 'ON' TypeOrPage .
8272: TypeOrPage = 'Page' [ '(' ViewID ')' ] /
8273: [ '*' ] ElemID .
8274: CounterValue = NUMBER .
8275:
8276: ConstSeq = Const < Const > .
8277: Const = ConstID '=' ConstType ConstValue ';' .
8278: ConstID = NAME .
8279: ConstType = 'Text' [ Alphabet ] / 'Symbol' /
8280: 'Graphics' / 'Picture' .
8281: ConstValue = STRING .
8282: Alphabet = NAME .
8283:
8284: VarSeq = Variable < Variable > .
8285: Variable = VarID ':' FunctionSeq ';' .
8286: VarID = NAME .
8287: FunctionSeq = Function < Function > .
8288: Function = 'DATE' / 'FDATE' /
8289: 'DocName' / 'DirName' /
8290: 'ElemName' / 'AttributeName' /
8291: ConstID / ConstType ConstValue /
8292: AttrID /
8293: 'VALUE' '(' PageAttrCtr ','
8294: CounterStyle ')' .
8295: PageAttrCtr = 'PageNumber' [ '(' ViewID ')' ] /
8296: [ MinMax ] CounterID / AttrID .
8297: CounterStyle = 'Arabic' / 'LRoman' / 'URoman' /
8298: 'Uppercase' / 'Lowercase' .
8299: MinMax = 'MaxRangeVal' / 'MinRangeVal' .
8300:
8301: BoxSeq = Box < Box > .
8302: Box = 'FORWARD' BoxID ';' /
8303: BoxID ':' ViewRuleSeq .
8304: BoxID = NAME .
8305:
8306: PresentSeq = Present < Present > .
8307: Present = [ '*' ] [ FirstSec ] ElemID ':'
8308: ViewRuleSeq .
8309: FirstSec = 'First' / 'Second' .
8310:
8311: PresAttrSeq = PresAttr < PresAttr > .
8312: PresAttr = AttrID [ '(' [ FirstSec ] ElemID ')' ]
8313: [ AttrRelation ] ':' ViewRuleSeq .
8314: AttrID = NAME .
8315: AttrRelation = '=' AttrVal /
8316: '>' [ '-' ] MinValue /
8317: '<' [ '-' ] MaxValue /
8318: 'IN' '[' [ '-' ] LowerBound '..'
8319: [ '-' ] UpperBound ']' /
8320: 'GREATER' AttrID /
8321: 'EQUAL' AttrID /
8322: 'LESS' AttrID .
8323: AttrVal = [ '-' ] EqualNum / EqualText / AttrValue .
8324: MinValue = NUMBER .
8325: MaxValue = NUMBER .
8326: LowerBound = NUMBER .
8327: UpperBound = NUMBER.
8328: EqualNum = NUMBER .
8329: EqualText = STRING .
8330: AttrValue = NAME .
8331:
8332: ViewRuleSeq = 'BEGIN' < RulesAndCond > < ViewRules >
8333: 'END' ';' /
8334: ViewRules / CondRules / Rule .
8335: RulesAndCond = CondRules / Rule .
8336: ViewRules = 'IN' ViewID CondRuleSeq .
8337: CondRuleSeq = 'BEGIN' < RulesAndCond > 'END' ';' /
8338: CondRules / Rule .
8339: CondRules = CondRule < CondRule >
8340: [ 'Otherwise' RuleSeq ] .
8341: CondRule = 'IF' ConditionSeq RuleSeq .
8342: RulesSeq = 'BEGIN' Rule < Rule > 'END' ';' / Rule .
8343:
1.6 cvs 8344: ConditionSeq = Condition < 'AND' Condition > .
8345: Condition = [ 'NOT' ] [ 'Target' ] ConditionElem .
8346: ConditionElem = 'First' / 'Last' /
8347: [ 'Immediately' ] 'Within' [ NumParent ]
8348: ElemID [ ExtStruct ] /
8349: ElemID /
8350: 'Referred' / 'FirstRef' / 'LastRef' /
8351: 'ExternalRef' / 'InternalRef' / 'CopyRef' /
8352: 'AnyAttributes' / 'FirstAttr' / 'LastAttr' /
8353: 'UserPage' / 'StartPage' / 'ComputedPage' /
8354: 'Empty' /
8355: '(' [ MinMax ] CounterName CounterCond ')' /
8356: CondPage '(' CounterID ')' .
8357: NumParent = [ GreaterLess ] NParent .
8358: GreaterLess = '>' / '<' .
8359: NParent = NUMBER.
8360: CounterCond = '<' MaxCtrVal / '>' MinCtrVal /
8361: '=' EqCtrVal /
8362: 'IN' '[' ['-'] MinCtrBound '..'
8363: ['-'] MaxCtrBound ']' .
8364: PageCond = 'Even' / 'Odd' / 'One' .
8365: MaxCtrVal = NUMBER .
8366: MinCtrVal = NUMBER .
8367: EqCtrVal = NUMBER .
8368: MaxCtrBound = NUMBER .
8369: MinCtrBound = NUMBER .
1.1 cvs 8370:
8371: Rule = PresParam ';' / PresFunc ';' .
8372: PresParam = 'VertRef' ':' HorizPosition /
8373: 'HorizRef' ':' VertPosition /
8374: 'VertPos' ':' VPos /
8375: 'HorizPos' ':' HPos /
8376: 'Height' ':' Extent /
8377: 'Width' ':' Extent /
8378: 'VertOverflow' ':' Boolean /
8379: 'HorizOverflow' ':' Boolean /
8380: 'LineSpacing' ':' DistOrInherit /
8381: 'Indent' ':' DistOrInherit /
8382: 'Adjust' ':' AlignOrInherit /
8383: 'Justify' ':' BoolInherit /
8384: 'Hyphenate' ':' BoolInherit /
8385: 'PageBreak' ':' Boolean /
8386: 'LineBreak' ':' Boolean /
8387: 'InLine' ':' Boolean /
8388: 'NoBreak1' ':' AbsDist /
8389: 'NoBreak2' ':' AbsDist /
8390: 'Gather' ':' Boolean /
8391: 'Visibility' ':' NumberInherit /
8392: 'Size' ':' SizeInherit /
8393: 'Font' ':' NameInherit /
8394: 'Style' ':' StyleInherit /
8395: 'Underline' ':' UnderLineInherit /
8396: 'Thickness' ':' ThicknessInherit /
8397: 'Depth' ':' NumberInherit /
8398: 'LineStyle' ':' LineStyleInherit /
8399: 'LineWeight' ':' DistOrInherit /
8400: 'FillPattern' ':' NameInherit /
8401: 'Background' ':' NameInherit /
8402: 'Foreground' ':' NameInherit .
8403: 'Content' ':' VarConst .
8404: PresFunc = Creation '(' BoxID ')' /
8405: 'Line' /
8406: 'NoLine' /
8407: 'Page' '(' BoxID ')' /
8408: 'Copy' '(' BoxTypeToCopy ')' .
8409:
8410: BoxTypeToCopy = BoxID [ ExtStruct ] /
8411: ElemID [ ExtStruct ] .
8412: ExtStruct = '(' ElemID ')' .
8413:
8414: Distance = [ Sign ] AbsDist .
8415: Sign = '+' / '-' .
8416: AbsDist = IntegerOrAttr [ '.' DecimalPart ]
8417: [ Unit ] .
8418: IntegerOrAttr = IntegerPart / AttrID .
8419: IntegerPart = NUMBER .
8420: DecimalPart = NUMBER .
8421: Unit = 'em' / 'ex' / 'cm' / 'mm' / 'in' / 'pt' /
8422: 'pc' / 'px' / '%' .
8423:
8424: HPos = 'nil' / VertAxis '=' HorizPosition
8425: [ 'UserSpecified' ] .
8426: VPos = 'nil' / HorizAxis '=' VertPosition
8427: [ 'UserSpecified' ] .
8428: VertAxis = 'Left' / 'VMiddle' / 'VRef' / 'Right' .
8429: HorizAxis = 'Top' / 'HMiddle' / 'HRef' / 'Bottom' .
8430:
1.6 cvs 8431: VertPosition = Reference '.' HorizAxis [ Distance ] .
8432: HorizPosition = Reference '.' VertAxis [ Distance ] .
8433: Reference = 'Enclosing' [ BoxTypeNot ] /
8434: 'Enclosed' [ BoxTypeNot ] /
8435: 'Previous' [ BoxTypeNot ] /
8436: 'Next' [ BoxTypeNot ] /
8437: 'Referred' [ BoxTypeNot ] /
8438: 'Creator' /
8439: 'Root' /
8440: '*' /
8441: BoxOrType .
8442: BoxOrType = BoxID /
8443: [ '*' ] [ FirstSec ] ElemID /
8444: 'AnyElem' / 'AnyBox' .
8445: BoxTypeNot = [ 'NOT' ] BoxOrType .
8446:
8447: Extent = Reference '.' HeightWidth
8448: [ Relation ] [ 'Min' ] /
8449: AbsDist [ 'UserSpecified' ] [ 'Min' ] /
8450: HPos / VPos .
8451: HeightWidth = 'Height' / 'Width' .
8452: Relation = '*' ExtentAttr '%' / Distance .
8453: ExtentAttr = ExtentVal / AttrID .
8454: ExtentVal = NUMBER .
8455:
8456: Inheritance = Kinship InheritedValue .
8457: Kinship = 'Enclosing' / 'GrandFather'/ 'Enclosed' /
8458: 'Previous' / 'Creator' .
8459: InheritedValue = '+' PosIntAttr [ 'Max' maximumA ] /
8460: '-' NegIntAttr [ 'Min' minimumA ] /
8461: '=' .
8462: PosIntAttr = PosInt / AttrID .
8463: PosInt = NUMBER .
8464: NegIntAttr = NegInt / AttrID .
8465: NegInt = NUMBER .
8466: maximumA = maximum / AttrID .
8467: maximum = NUMBER .
8468: minimumA = minimum / AttrID .
8469: minimum = NUMBER .
8470:
8471: AlignOrInherit = Kinship '=' / Alignment .
8472: Alignment = 'Left' / 'Right' / 'VMiddle' /
8473: 'LeftWithDots' .
1.1 cvs 8474:
1.6 cvs 8475: DistOrInherit = Kinship InheritedDist / Distance .
8476: InheritedDist = '=' / '+' AbsDist / '-' AbsDist .
1.1 cvs 8477:
1.6 cvs 8478: BoolInherit = Boolean / Kinship '=' .
8479: Boolean = 'Yes' / 'No' .
1.1 cvs 8480:
1.6 cvs 8481: NumberInherit = Integer / AttrID / Inheritance .
8482: Integer = NUMBER .
1.1 cvs 8483:
8484: LineStyleInherit= Kinship '=' / 'Solid' / 'Dashed' /
8485: 'Dotted' .
8486:
1.6 cvs 8487: SizeInherit = SizeAttr [ 'pt' ] / Kinship InheritedSize .
8488: InheritedSize = '+' SizeAttr [ 'pt' ]
8489: [ 'Max' MaxSizeAttr ] /
8490: '-' SizeAttr [ 'pt' ]
8491: [ 'Min' MinSizeAttr ] /
8492: '=' .
8493: SizeAttr = Size / AttrID .
8494: Size = NUMBER .
8495: MaxSizeAttr = MaxSize / AttrID .
8496: MaxSize = NUMBER .
8497: MinSizeAttr = MinSize / AttrID .
8498: MinSize = NUMBER .
8499:
8500: NameInherit = Kinship '=' / FontName .
8501: FontName = NAME .
8502: StyleInherit = Kinship '=' /
8503: 'Roman' / 'Bold' / 'Italics' /
8504: 'BoldItalics' / 'Oblique' / 'BoldOblique' .
1.1 cvs 8505: UnderLineInherit= Kinship '=' /
1.6 cvs 8506: 'NoUnderline' / 'Underlined' /
8507: 'Overlined' / 'CrossedOut' .
1.1 cvs 8508: ThicknessInherit= Kinship '=' / 'Thick' / 'Thin' .
8509:
1.6 cvs 8510: VarConst = ConstID / ConstType ConstValue /
8511: VarID / '(' FunctionSeq ')' /
8512: ElemID .
8513:
8514: Creation = Create [ 'Repeated' ] .
8515: Create = 'CreateFirst' / 'CreateLast' /
8516: 'CreateBefore' / 'CreateAfter' /
8517: 'CreateEnclosing' .
8518:
8519: TransmitSeq = Transmit < Transmit > .
8520: Transmit = TypeOrCounter 'To' ExternAttr
8521: '(' ElemID ')' ';' .
8522: TypeOrCounter = CounterID / ElemID .
8523: ExternAttr = NAME .
1.1 cvs 8524:
8525: END
8526: </PRE>
8527: </DIV>
8528:
8529: <DIV class="section">
1.6 cvs 8530: <H2><A name=sectb64>The T language</A></H2>
1.1 cvs 8531:
8532: <PRE>
8533: TransSchema = 'TRANSLATION' ElemID ';'
8534: [ 'LINELENGTH' LineLength ';' ]
8535: [ 'LINEEND' CHARACTER ';' ]
8536: [ 'LINEENDINSERT' STRING ';' ]
8537: [ 'BUFFERS' BufferSeq ]
8538: [ 'COUNTERS' CounterSeq ]
8539: [ 'CONST' ConstSeq ]
8540: [ 'VAR' VariableSeq ]
8541: 'RULES' ElemSeq
8542: [ 'ATTRIBUTES' AttrSeq ]
8543: [ 'PRESENTATION' PresSeq ]
8544: < 'TEXTTRANSLATE' TextTransSeq >
8545: [ 'SYMBTRANSLATE' TransSeq ]
8546: [ 'GRAPHTRANSLATE' TransSeq ]
8547: 'END' .
8548:
8549: LineLength = NUMBER .
8550:
8551: BufferSeq = Buffer < Buffer > .
8552: Buffer = BufferID [ '(' 'Picture' ')' ] ';' .
8553: BufferID = NAME .
8554:
8555: CounterSeq = Counter < Counter > .
8556: Counter = CounterID [ ':' CounterFunc ] ';' .
8557: CounterID = NAME .
8558: CounterFunc = 'Rank' 'of' ElemID [ SLevelAsc ]
8559: [ 'Init' AttrID ] /
8560: 'Rlevel' 'of' ElemID /
8561: 'Set' InitValue 'On' ElemID
8562: 'Add' Increment 'On' ElemID
8563: [ 'Init' AttrID ] .
8564: SLevelAsc = [ '-' ] LevelAsc .
8565: LevelAsc = NUMBER .
8566: InitValue = NUMBER .
8567: Increment = NUMBER .
8568: ElemID = NAME .
8569: AttrID = NAME .
8570:
8571: ConstSeq = Const < Const > .
8572: Const = ConstID '=' ConstValue ';' .
8573: ConstID = NAME .
8574: ConstValue = STRING .
8575:
8576: VariableSeq = Variable < Variable > .
8577: Variable = VarID ':' Function < Function > ';' .
8578: VarID = NAME .
8579: Function = 'Value' '(' CounterID [ ':' Length ]
8580: [ ',' CounterStyle ] ')' /
8581: 'FileDir' / 'FileName' / 'Extension' /
8582: 'DocumentName' / 'DocumentDir' /
8583: ConstID / CharString /
8584: BufferID / AttrID .
8585: Length = NUMBER .
8586: CounterStyle= 'Arabic' / 'LRoman' / 'URoman' /
8587: 'Uppercase' / 'Lowercase' .
8588: CharString = STRING .
8589:
8590: ElemSeq = TransType < TransType > .
8591: TransType = [ FirstSec ] ElemID ':' RuleSeq .
8592: FirstSec = 'First' / 'Second' .
8593: RuleSeq = Rule / 'BEGIN' < Rule > 'END' ';' .
8594: Rule = SimpleRule / ConditionBlock .
8595: ConditionBlock= 'IF' ConditionSeq SimpleRuleSeq .
8596: SimpleRuleSeq = 'BEGIN' < SimpleRule > 'END' ';' /
8597: SimpleRule .
8598:
8599: ConditionSeq = Condition [ 'AND' Condition ] .
8600: Condition = [ 'NOT' ] [ 'Target' ] Cond .
8601: Cond = CondElem / CondAscend .
8602: CondElem = 'FirstRef' / 'LastRef' /
8603: 'ExternalRef' /
8604: 'Defined' /
8605: 'Alphabet' '=' Alphabet /
8606: 'ComputedPage' / 'StartPage' /
8607: 'UserPage' / 'ReminderPage' /
8608: 'Empty' /
1.11 cvs 8609: ElemID /
1.1 cvs 8610: 'FirstAttr' / 'LastAttr' .
8611: CondAscend = [ Ascend ] CondOnAscend .
8612: Ascend = '*' / 'Parent' / 'Ancestor' LevelOrType .
8613: LevelOrType = CondRelLevel / ElemID [ ExtStruct ] .
8614: CondRelLevel = NUMBER .
8615: CondOnAscend = 'First' / 'Last' /
8616: 'Referred' /
8617: [ 'Immediately' ] 'Within' [ NumParent ]
8618: ElemID [ ExtStruct ] /
8619: 'Attributes' /
8620: AttrID [ RelatAttr ] /
8621: 'Presentation' /
8622: PresRule /
8623: 'Comment' .
8624: NumParent = [ GreaterLess ] NParent .
8625: GreaterLess = '>' / '<' .
8626: NParent = NUMBER.
8627: Alphabet = NAME .
8628: RelatAttr = '=' Value /
8629: '>' [ '-' ] Minimum /
8630: '<' [ '-' ] Maximum /
8631: 'IN' '[' [ '-' ] MinInterval '..'
8632: [ '-' ] MaxInterval ']' .
8633: Value = [ '-' ] IntegerVal / TextVal / AttrValue .
8634: Minimum = NUMBER .
8635: Maximum = NUMBER .
8636: MinInterval = NUMBER .
8637: MaxInterval = NUMBER .
8638: IntegerVal = NUMBER .
8639: TextVal = STRING .
8640: AttrValue = NAME .
8641:
8642: SimpleRule = 'Create' [ 'IN' VarID ] Object
8643: [ Position ] ';' /
8644: 'Write' Object [ Position ] ';' /
8645: 'Read' BufferID [ Position ] ';' /
8646: 'Include' File [ Position ] ';' /
1.6 cvs 8647: 'Get' [ RelPosition ] ElemID
8648: [ ExtStruct ]
8649: [ Position ] ';' /
1.1 cvs 8650: 'Copy' [ RelPosition ] ElemID
8651: [ ExtStruct ]
8652: [ Position ] ';' /
8653: 'Use' TrSchema [ 'For' ElemID ] ';' /
8654: 'Remove' ';' /
8655: 'NoTranslation' ';' /
8656: 'NoLineBreak' ';' /
8657: 'ChangeMainFile' VarID [ Position ] ';' /
1.10 cvs 8658: 'Set' CounterID InitValue [ Position ] ';' /
8659: 'Add' CounterID Increment [ Position ] ';' /
8660: 'Indent' [ 'IN' VarID ] [ IndentSign ]
8661: IndentValue [ Position ] ';' .
8662:
8663: IndentSign = '+' / '-' .
8664: IndentValue = NUMBER .
1.1 cvs 8665:
8666: Object = ConstID / CharString /
8667: BufferID /
8668: VarID /
8669: '(' Function < Function > ')' /
8670: AttrID /
8671: 'Value' /
8672: 'Content' /
8673: 'Comment' /
8674: 'Attributes' /
8675: 'Presentation' /
8676: 'RefId' /
8677: 'PairId' /
8678: 'FileDir' / 'FileName' / 'Extension' /
8679: 'DocumentName' / 'DocumentDir' /
8680: [ 'Referred' ] ReferredObject .
8681: Position = 'After' / 'Before' .
8682:
1.6 cvs 8683: ReferredObject= VarID /
8684: ElemID [ ExtStruct ] /
8685: 'RefId' /
8686: 'DocumentName' / 'DocumentDir' .
1.1 cvs 8687:
1.6 cvs 8688: File = FileName / BufferID .
8689: FileName = STRING .
1.1 cvs 8690:
1.6 cvs 8691: RelPosition = 'Included' / 'Referred' .
8692: ExtStruct = '(' ElemID ')' .
1.1 cvs 8693:
1.6 cvs 8694: TrSchema = NAME .
8695:
8696: AttrSeq = TransAttr < TransAttr > .
8697: TransAttr = AttrID [ '(' ElemID ')' ]
8698: [ RelatAttr ] ':' RuleSeq .
8699:
8700: PresSeq = PresTrans < PresTrans > .
8701: PresTrans = PresRule ':' RuleSeq .
8702: PresRule = 'Size' [ PresRelation ] /
8703: 'Indent' [ PresRelation ] /
8704: 'LineSpacing' [ PresRelation ] /
8705: 'Adjust' [ '=' AdjustVal ] /
8706: 'Justify' [ '=' BoolVal ] /
8707: 'Hyphenate' [ '=' BoolVal ] /
8708: 'Style' [ '=' StyleVal ] /
8709: 'Font' [ '=' FontVal ] /
8710: 'UnderLine' [ '=' UnderLineVal ] /
8711: 'Thickness' [ '=' ThicknessVal ] /
8712: 'LineStyle' [ '=' LineStyleVal ] /
8713: 'LineWeight' [ PresRelation ] /
8714: 'FillPattern' [ '=' Pattern ] /
8715: 'Background' [ '=' Color ] /
8716: 'Foreground' [ '=' Color ] .
8717:
8718: PresRelation = '=' PresValue /
8719: '>' [ '-' ] PresMinimum /
8720: '<' [ '-' ] PresMaximum /
8721: 'IN' '[' [ '-' ] PresIntervalMin '..'
8722: [ '-' ] PresIntervalMax ']' .
8723: AdjustVal = 'Left' / 'Right' / 'VMiddle' /
8724: 'LeftWithDots' .
8725: BoolVal = 'Yes' / 'No' .
8726: StyleVal = 'Bold' / 'Italics' / 'Roman' /
8727: 'BoldItalics' / 'Oblique' /
8728: 'BoldOblique' .
8729: FontVal = 'Times' / 'Helvetica' / 'Courier' .
8730: UnderLineVal = 'NoUnderline' / 'UnderLined' /
8731: 'OverLined' / 'CrossedOut' .
8732: ThicknessVal = 'Thick' / 'Thin' .
8733: LineStyleVal = 'Solid' / 'Dashed' / 'Dotted' .
8734: Pattern = NAME .
8735: Color = NAME .
8736: PresMinimum = NUMBER .
8737: PresMaximum = NUMBER .
1.1 cvs 8738: PresIntervalMin= NUMBER .
8739: PresIntervalMax= NUMBER .
1.6 cvs 8740: PresValue = [ '-' ] PresVal .
8741: PresVal = NUMBER .
1.1 cvs 8742:
1.6 cvs 8743: TextTransSeq = [ Alphabet ] TransSeq .
8744: Alphabet = NAME .
8745: TransSeq = 'BEGIN' < Translation > 'END' ';' /
8746: Translation .
8747: Translation = Source [ '->' Target ] ';' .
8748: Source = STRING .
8749: Target = STRING .
1.1 cvs 8750: </PRE>
8751: </DIV>
8752: <HR>
8753: </DIV>
8754:
8755: <DIV class="chapter">
1.6 cvs 8756: <H1><A name=sect7>Character coding</A></H1>
1.1 cvs 8757:
8758:
8759: <DIV class="section">
1.6 cvs 8760: <H2><A name=sectb71>Characters</A></H2>
1.1 cvs 8761:
8762: <P>
8763: The characters of the Latin alphabet follow the encoding defined in the ISO
1.5 cvs 8764: 8859-1 (ISO Latin-1) standard. The characters of the Greek alphabet follow
1.1 cvs 8765: the encoding defined by Adobe for its Symbol font (Adobe FontSpecific).</P>
8766: <P>
8767: Characters whose octal code is greater than 0200 are written in the form of
8768: their octal code preceded by a backslash character (``\''). For example, the
1.5 cvs 8769: French word 'Résumé' is written <TT>R\351sum\351</TT>.</P>
1.1 cvs 8770: <P>
1.2 cvs 8771: To the ISO 8859-1 encoding four characters with the following codes have been
1.1 cvs 8772: added:<BR><TT>212</TT>: line break<BR><TT>240</TT>: sticky
1.2 cvs 8773: space<BR><TT>201</TT>: thin space<BR><TT>202</TT>: en space</P>
1.1 cvs 8774: <P>
8775: The <TT>212</TT> character is a ``line break'' character which forces a line
8776: break. The <TT>240</TT> character is a ``sticky space'', which cannot be
8777: replaced by a line break.</P>
8778: </DIV>
8779:
8780: <DIV class="section">
1.6 cvs 8781: <H2><A name=sectb72>Symbols</A></H2>
1.1 cvs 8782:
8783: <P>
8784: The table below gives the codes for the symbols of Thot. Symbols can be used
8785: in presentation schemas constants and in transcoding rules of translation
8786: schemas. Each symbol is represented by a single character.</P>
8787: <UL>
8788: <LI><TT>r</TT>: a radical
8789: <LI><TT>i</TT>: a simple integral
8790: <LI><TT>c</TT>: a curvilinear integral
8791: <LI><TT>d</TT>: a double integral
8792: <LI><TT>t</TT>: a triple integral
8793: <LI><TT>S</TT>: the summation symbol
8794: <LI><TT>P</TT>: the product symbol
8795: <LI><TT>U</TT>: the union symbol
8796: <LI><TT>I</TT>: the intersection symbol
8797: <LI><TT>></TT>: a right arrow
8798: <LI><TT><</TT>: a left arrow
8799: <LI><TT>^</TT>: an up arrow
8800: <LI><TT>V</TT>: a down arrow
8801: <LI><TT>(</TT>: an opening parenthesis
8802: <LI><TT>)</TT>: a closing parenthesis
8803: <LI><TT>{</TT>: an opening brace
8804: <LI><TT>}</TT>: a closing brace
8805: <LI><TT>[</TT>: an opening bracket
8806: <LI><TT>]</TT>: a closing bracket
8807: </UL>
8808: </DIV>
8809:
8810: <DIV class="section">
1.6 cvs 8811: <H2><A name=sectb73>Graphical elements</A></H2>
1.1 cvs 8812:
8813: <P>
8814: The table below gives the codes for the graphical elements of Thot. These
8815: elements can be used in presentation schemas constants and in transcoding
8816: rules of translation schemas. Each graphical element is represented by a
8817: single character.</P>
8818: <UL>
8819: <LI><TT>c</TT>: an ellipse inscribed in the box
8820: <LI><TT>R</TT>: a rectangle which is the shape of the box
8821: <LI><TT>C</TT>: a rectangle with rounded corners
8822: <LI><TT>t</TT>: a horizontal line along the upper side of the box
8823: <LI><TT>h</TT>: a horizontal line as wide as the box and placed in its middle
8824: <LI><TT>b</TT>: a horizontal line along the lower side of the box
8825: <LI><TT>></TT>: a right arrow as long as the box's width and in its middle
8826: <LI><TT>></TT>: a left arrow as long as the box's width and in its middle
8827: <LI><TT>l</TT>: a vertical line on the left side of the box
8828: <LI><TT>v</TT>: a vertical line as tall as the box and placed in its middle
8829: <LI><TT>r</TT>: a vertical line on the right side of the box
8830: <LI><TT>^</TT>: an up arrow as tall as the box and in its middle
8831: <LI><TT>V</TT>: a down arrow as tall as the box and in its middle
8832: <LI><TT>/</TT>: The southwest/northeast diagonal of the box
8833: <LI><TT>\</TT>: the northwest/southeast diagonal of the box
1.2 cvs 8834: <LI><TT>O</TT>: The northwest/southeast diagonal of the box with an arrowhead
1.1 cvs 8835: at the top
1.2 cvs 8836: <LI><TT>e</TT>: The northwest/southeast diagonal of the box with an arrowhead
1.1 cvs 8837: at the bottom
1.2 cvs 8838: <LI><TT>E</TT>: The southwest/northeast diagonal of the box with an arrowhead
1.1 cvs 8839: at the top
1.2 cvs 8840: <LI><TT>o</TT>: The southwest/northeast diagonal of the box with an arrowhead
1.1 cvs 8841: at the bottom
8842: <LI><TT>space</TT>: a transparent element
1.2 cvs 8843: <LI><TT>P</TT>: a rectangle with round corners and a horizontal bar at the top
1.1 cvs 8844: <LI><TT>Q</TT>: an ellipse with a horizontal bar at the top
8845: <LI><TT>L</TT>: a lozenge
8846: <LI><TT>W</TT>: the upper right corner
8847: <LI><TT>X</TT>: the lower right corner
8848: <LI><TT>Y</TT>: the lower left corner
8849: <LI><TT>Z</TT>: the upper left corner
8850: <LI><TT>p</TT>: a polygon
8851: <LI><TT>S</TT>: an open broken line
8852: <LI><TT>N</TT>: an open broken line with an arrow head at start
8853: <LI><TT>U</TT>: an open broken line with an arrow head at the end
8854: <LI><TT>M</TT>: an open broken line with two arrow heads
8855: <LI><TT>s</TT>: a closed curve
8856: <LI><TT>B</TT>: an open curve
8857: <LI><TT>F</TT>: an open curve with an arrow head at start
8858: <LI><TT>A</TT>: an open curve with an arrow head at the end
8859: <LI><TT>D</TT>: an open curve with two arrow heads
8860: </UL>
1.5 cvs 8861: <HR>
1.1 cvs 8862: </DIV>
8863: </DIV>
8864: </BODY>
8865: </HTML>
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