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! 2: <HTML>
! 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:
! 13: <H4>translated by Ethan Munson</H4>
! 14:
! 15: <H4>Version of December 14, 1996</H4>
! 16:
! 17: <HR>
! 18: </DIV>
! 19:
! 20: <DIV class="chapter">
! 21: <H1>The document model of Thot</H1>
! 22:
! 23: <P>
! 24: All of the services which Thot provides to the user are based on the system's
! 25: internal document representation. This representation is itself derived from
! 26: the document model which underlies Thot. The model is presented here, prior
! 27: to the description of the languages which permit the generic specification of
! 28: documents.</P>
! 29:
! 30: <DIV class="section">
! 31: <H2>The logical structure of documents</H2>
! 32:
! 33: <P>
! 34: The document model of Thot is primarily designed to allow the user to operate
! 35: on those entities which he has in mind when he works on a document. The model
! 36: makes no assumptions about the nature of these entities. It is essentially
! 37: these logical entities, such as paragraphs, sections, chapters, notes, titles,
! 38: and cross-references which give a document its logical structure.</P>
! 39: <P>
! 40: Because of this model, the author can divide his document into chapters,
! 41: giving each one a title. The content of these chapters can be further divided
! 42: into sections, subsections, etc.. The text is organized into successive
! 43: paragraphs, as a function of the content. In the writing phase, the lines,
! 44: pages, margins, spacing, fonts, and character styles are not very important.
! 45: In fact, if the system requires documents to be written in these terms, it
! 46: gets in the way. So, Thot's model is primarily based on the logical aspect of
! 47: documents. The creation of a model of this type essentially requires the
! 48: definition :</P>
! 49: <UL>
! 50: <LI>of the entities which can appear in the documents,
! 51: <LI>and the relations between these entities.
! 52: </UL>
! 53: <P>
! 54: The choice of entities to include in the model can be subtle. Some documents
! 55: require chapters, while others only need various levels of sections. Certain
! 56: documents contain appendices, others don't. In different documents the same
! 57: logical entity may go by different names (e.g. ``Conclusion'' and
! 58: ``Summary''). Certain entities which are absolutely necessary in some
! 59: documents, such as clauses in a contract or the address of the recipient in a
! 60: letter, are useless in most other cases.</P>
! 61: <P>
! 62: The differences between documents result from more than just the entities that
! 63: appear in them, but also from the relationships between these entities and the
! 64: ways that they are linked. In certain documents, notes are spread throughout
! 65: the document, for example at the bottom of the page containing the
! 66: cross-reference to them, while in other documents they are collected at the
! 67: end of each chapter or even at the end of the work. As another example, the
! 68: introduction of some documents can contain many sections, while in other
! 69: documents, the introduction is restricted to be a short sequence of
! 70: paragraphs.</P>
! 71: <P>
! 72: All of this makes it unlikely that a single model can describe any document at
! 73: a relatively high level. It is obviously tempting to make up a list of widely
! 74: used entities, such as chapters, sections, paragraphs, and titles, and then
! 75: map all other entities onto the available choices. In this way, an
! 76: introduction can be supported as a chapter and a contract clause supported as
! 77: a paragraph or section. However, in trying to widen the range of usage of
! 78: certain entities, their meaning can be lost and the power of the model
! 79: reduced. In addition, while this widening partially solves the problem of
! 80: choosing entities, it does not solve the problem of their organization: when a
! 81: chapter must be composed of sections, how does one indicate that an
! 82: introduction has none when it is merely another chapter? One solution is to
! 83: include introductions in the list of supported entities. But then, how does
! 84: one distinguish those introductions which are allowed to have sections from
! 85: those which are not. Perhaps this could be done by defining two types of
! 86: introduction. Clearly, this approach risks an infinite expansion of the list
! 87: of widely used entities.</P>
! 88: </DIV>
! 89:
! 90: <DIV class="section">
! 91: <H2>Generic and specific structures</H2>
! 92:
! 93: <P>
! 94: Thus, it is apparently impossible to construct an exhaustive inventory of all
! 95: those entities which are necessary and sufficient to describe any document. It
! 96: also seems impossible to specify all possible arrangements of these entities
! 97: in a document. This is why Thot uses a <EM>meta-model</EM> instead, which
! 98: permits the description of numerous <EM>models</EM>, each one describing a
! 99: <EM>class</EM> of documents.</P>
! 100: <P>
! 101: A <EM>class</EM> is a set of documents having very similar structure. Thus,
! 102: the collection of research reports published by a laboratory constitutes a
! 103: class; the set of commercial proposals by the sales department of a company
! 104: constitutes another class; the set of articles published by a journal
! 105: constitutes a third class. Clearly, it is not possible to enumerate every
! 106: possible document class. It is also clear that new document classes must be
! 107: created to satisfy new needs and applications.</P>
! 108: <P>
! 109: To give a more rigorous definition of classes, we must introduce the ideas of
! 110: <EM>generic structure</EM> and <EM>specific structure</EM>. Each document has
! 111: a <EM>specific structure</EM> which organizes the various parts which comprise
! 112: it. We illustrate this with the help of a simple example comparing two
! 113: reports, A and B (<A href="#specstruct">see Figure</A>). The report A contains
! 114: an introduction followed by three chapters and a conclusion. The first
! 115: chapter contains two sections, the second, three sections. That is the
! 116: <EM>specific</EM> structure of document A. Similarly, the structure of
! 117: document B is: an introduction, two chapters, a conclusion; Chapter 1 has
! 118: three sections while Chapter 2 has four. The specific structures of these two
! 119: documents are thus different.</P>
! 120:
! 121: <DIV class="figure">
! 122: <HR>
! 123: <PRE>
! 124: Report A Report B
! 125: Introduction Introduction
! 126: Chapter 1 Chapter 1
! 127: Section 1.1 Section 1.1
! 128: Section 1.2 Section 1.2
! 129: Chapter 2 Section 1.3
! 130: Section 2.1 Chapter 2
! 131: Section 2.2 Section 2.1
! 132: Section 2.3 Section 2.2
! 133: Chapter 3 Section 2.3
! 134: Conclusion Section 2.4
! 135: Conclusion
! 136: </PRE>
! 137: <P align=center>
! 138: <EM><A name="specstruct">Two specific structures</A></EM></P>
! 139: <HR>
! 140: </DIV>
! 141: <P>
! 142: The <EM>generic structure</EM> defines the ways in which specific structures
! 143: can be constructed. It specifies how to generate specific structures. The
! 144: reports A and B, though different, are constructed in accordance with the same
! 145: generic structure, which specifies that a report contains an introduction
! 146: followed by a variable number of chapters and a conclusion, with each chapter
! 147: containing a variable number of sections.</P>
! 148: <P>
! 149: There is a one-to-one correspondence between a class and a generic structure:
! 150: all the documents of a class are constructed in accordance with the same
! 151: generic structure. Hence the definition of the class: a class is a set of
! 152: documents whose specific structure is constructed in accordance with the same
! 153: generic structure. A class is characterized by its generic structure.</P>
! 154: <P>
! 155: Thus, a generic structure can be considered to be a model at the level which
! 156: interests us, but only for one class of documents. When the definition is
! 157: limited to a single class of documents, it is possible to define a model which
! 158: does a good job of representing the documents of the class, including the
! 159: necessary entities and unencumbered by useless entities. The description of
! 160: the organization of the documents in the class can then be sufficiently
! 161: precise.</P>
! 162: </DIV>
! 163:
! 164: <DIV class="section">
! 165: <H2>Logical structure and physical structure</H2>
! 166:
! 167: <P>
! 168: Generic structures only describe the <EM>logical</EM> organization of
! 169: documents, not their <EM>physical</EM> presentation on a screen or on sheets
! 170: of paper. However, for a document to be displayed or printed, its graphic
! 171: presentation must be taken into account.</P>
! 172: <P>
! 173: An examination of current printed documents shows that the details of
! 174: presentation essentially serve to bring out their logical structure. Outside
! 175: of some particular domains, notably advertising, the presentation is rarely
! 176: independent of the logical organization of the text. Moreover, the art of
! 177: typography consists of enhancing the organization of the text being set,
! 178: without catching the eye of the reader with overly pronounced effects. Thus,
! 179: italic and boldface type are used to emphasize words or expressions which have
! 180: greater significance than the rest of the text: keywords, new ideas,
! 181: citations, book titles, etc. Other effects highlight the organization of the
! 182: text: vertical space, margin changes, page breaks, centering, eventually
! 183: combined with the changes in the shapes or weight of the characters. These
! 184: effects serve to indicate the transitions between paragraphs, sections, or
! 185: chapters: an object's level in the logical structure of the document is shown
! 186: by the markedness of the effects.</P>
! 187: <P>
! 188: Since the model permits the description of all of the logical structure of the
! 189: document, the presentation can be derived from the model without being
! 190: submerged in the document itself. It suffices to use the logical structure of
! 191: the document to make the desired changes in its presentation: changes in type
! 192: size, type style, spacing, margin, centering, etc.</P>
! 193: <P>
! 194: Just as one cannot define a unique generic logical structure for all document
! 195: classes, one cannot define universal presentation rules which can be applied
! 196: to all document classes. For certain types of documents the chapter titles
! 197: will be centered on the page and printed in large, bold type. For other
! 198: documents, the same chapter titles will be printed in small, italic type and
! 199: aligned on the left margin.</P>
! 200: <P>
! 201: Therefore, it is necessary to base the presentation specifications for
! 202: documents on their class. Such a specification can be very fine-grained,
! 203: because the presentation is expressed in terms of the entities defined in the
! 204: generic logical structure of the class. Thus, it is possible to specify a
! 205: different presentation for the chapter titles and the section titles, and
! 206: similarly to specify titles for the sections according to their level in the
! 207: section hierarchy. The set of rules which specify the presentation of all the
! 208: elements defined in a generic logical structure is called a <EM>generic
! 209: presentation</EM>.</P>
! 210: <P>
! 211: There are several advantages derived from having a presentation linked to the
! 212: generic structure and described by a generic presentation. Homogeneity is the
! 213: first. Since every document in a class corresponds to the same generic
! 214: logical structure, a homogenous presentation for different documents of the
! 215: same class can be assured by applying the same generic presentation to all
! 216: documents of the class. Homogeneity of presentation can also be found among
! 217: the entities of a single document: every section title will be presented in
! 218: the same way, the first line of every paragraph of the same type will have the
! 219: same indentation, etc.</P>
! 220: <P>
! 221: Another advantage of this approach to presentation is that it facilitates
! 222: changes to the graphical aspect of documents. A change to the generic
! 223: presentation rules attached to each type of entity will alter the presentation
! 224: of the entire document, and will do so homogenously. In this case, the
! 225: internal homogeneity of the class is no longer assured, but the way to control
! 226: it is simple. It suffices to adopt a single generic presentation for the
! 227: entire class.</P>
! 228: <P>
! 229: If the presentation of the class does not have to be homogenous, then the
! 230: appearance of the document can be adapted to the way it will be used or to the
! 231: device used to render it. This quality is sufficient to allow the existence
! 232: of <A name="mulpres">many generic presentations</A> for the same document
! 233: class. By applying one or the other of these presentations to it, the document
! 234: can be seen under different graphical aspects. It must be emphasized that
! 235: this type of modification of the presentation is not a change to the document
! 236: itself (in its specific logical structure or its content), but only in its
! 237: appearance at the time of editing or printing.</P>
! 238: </DIV>
! 239:
! 240: <DIV class="section">
! 241: <H2>Document structures and object structures</H2>
! 242:
! 243: <P>
! 244: So far, we have only discussed the global structure of documents and have not
! 245: considered the contents found in that structure. We could limit ourselves to
! 246: purely textual contents by assuming that a title or a paragraph contains a
! 247: simple linear text. But this model would be too restrictive. In fact,
! 248: certain documents contain not only text, but also contain tables, diagrams,
! 249: photographs, mathematical formulas, and program fragments. The model must
! 250: permit the representation of such <EM>objects</EM>.</P>
! 251: <P>
! 252: Just as with the whole of the document, the model takes into account the
! 253: logical structure of objects of this type. Some are clearly structured,
! 254: others are less so. Logical structure can be recognized in mathematical
! 255: formulas, in tables, and in certain types of diagrams. On the other hand, it
! 256: is difficult to define the structure of a photograph or of some drawings. But
! 257: in any case, it does not seem possible to define one unique structure which
! 258: can represent every one of these types of objects. The approach taken in the
! 259: definition of meta-structure and document classes also applies to objects.
! 260: Object classes can be defined which put together objects of similar type,
! 261: constructed from the same generic logical structure.</P>
! 262: <P>
! 263: Thus, a mathematical class can be defined and have a generic logical structure
! 264: associated with it. But even if a single generic structure can represent a
! 265: sufficient variety of mathematical formulas, for other objects with less
! 266: rigorous structure, multiple classes must be defined. As for documents, using
! 267: multiple classes assures that the model can describe the full range of objects
! 268: to be presented. It also permits the system to support objects which were not
! 269: initially anticipated. Moreover, this comment applies equally to mathematics:
! 270: different classes of formulas can be described depending on the domain of
! 271: mathematics being described.</P>
! 272: <P>
! 273: Since objects have the same level of logical representation as documents, they
! 274: gain the same advantages. In particular, it is possible to define the
! 275: presentation separately from the objects themselves and attach it to the
! 276: class. Thus, as for documents, objects of the same type have a uniform
! 277: presentation and the presentation of every object in a given class can be
! 278: changed simply by changing the generic presentation of the class. Another
! 279: advantage of using this document model is that the system does not bother the
! 280: user with the details of presentation, but rather allows the user to
! 281: concentrate on the logical aspect of the document and the objects.</P>
! 282: <P>
! 283: It is clear that the documents in a class do not necessarily use the same
! 284: classes of objects: one technical report will contain tables while another
! 285: report will have no tables but will use mathematical formulas. The usable
! 286: object classes are not mentioned in a limiting way in the generic logical
! 287: structure of documents. Rather, they can be chosen freely from a large set,
! 288: independent of the document class.</P>
! 289: <P>
! 290: Thus, the object classes will be made commonplace and usable in every
! 291: document. The notion of ``object'' can be enlarged to include not only
! 292: non-textual elements, but also certain types of textual elements which can
! 293: appear in practically every document, whatever their class. Among these
! 294: textual elements, one can mention certain elements defined by LaTeX as
! 295: <EM>environments</EM>: enumerations, descriptions, examples, quotations, even
! 296: paragraphs.</P>
! 297: <P>
! 298: Thus, the document model is not a single, general model describing every type
! 299: of document in one place. Rather, it is a meta-model which can be used to
! 300: describe many different models each of which represents either a class of
! 301: similar documents or a class of similar objects which every document can
! 302: include.</P>
! 303: </DIV>
! 304: <HR>
! 305: </DIV>
! 306:
! 307: <DIV class="chapter">
! 308: <H1>The S language</H1>
! 309:
! 310:
! 311: <DIV class="section">
! 312: <H2>Document meta-structure</H2>
! 313:
! 314: <P>
! 315: Since the concept of meta-structure is well suited to the task of describing
! 316: documents at a high level of abstraction, this meta-structure must be
! 317: precisely defined. Toward that end this section first presents the basic
! 318: elements from which documents and structured objects are composed and then
! 319: specifies the ways in which these basic elements are assembled into structures
! 320: representing complete documents and objects.</P>
! 321:
! 322: <DIV class="subsection">
! 323: <H3>The basic types</H3>
! 324:
! 325: <P>
! 326: At the lowest level of a document's structure, the first atom considered is
! 327: the character. However, since characters are seldom isolated, usually
! 328: appearing as part of a linear sequence, and in order to reduce the complexity
! 329: of the document structure, <EM>character strings</EM> are used as atoms and
! 330: consecutive characters belonging to the same structural element are grouped in
! 331: the same character string.</P>
! 332: <P>
! 333: If the structure of a document is not refined to go down to the level of
! 334: words or phrases, the contents of a simple paragraph can be considered to be a
! 335: single character string. On the other hand, the title of a chapter, the title
! 336: of the first section of that chapter, and the text of the first paragraph of
! 337: that section constitute three different character strings, because they belong
! 338: to distinct structural elements.</P>
! 339: <P>
! 340: If, instead, a very fine-grained representation for the structure of a
! 341: document is sought, character strings could be defined to contain only a
! 342: single word, or even just a single character. This is the case, for example,
! 343: in programs, for which one wants to retain a structure very close to the
! 344: syntax of the programming language. In this case, a assignment statement
! 345: initializing a simple variable to zero would be composed of two structural
! 346: elements, the identifier of the variable (a short character string) and the
! 347: assigned value (a string of a single character, `0').</P>
! 348: <P>
! 349: The character string is not the only atom necessary for representing those
! 350: documents that interest us. It suffices for purely textual documents, but as
! 351: soon as the non-textual objects which we have considered arise, there must be
! 352: other atoms; the number of objects which are to be represented determines the
! 353: number of types of atoms that are necessary.</P>
! 354: <P>
! 355: Primitive <EM>graphical elements</EM> are used for tables and figures of
! 356: different types. These elements are simple geometric shapes like horizontal
! 357: or vertical lines, which are sufficient for tables, or even oblique lines,
! 358: arrows, rectangles, and circles for use in figures. From these elements and
! 359: character strings, graphical objects and tables can be constructed.</P>
! 360: <P>
! 361: Photographs, though having very little structure, must still appear in
! 362: documents. They are supported by <EM>image</EM> elements, which are
! 363: represented as matrices of points.</P>
! 364: <P>
! 365: Finally, mathematical notations require certain elements which are
! 366: simultaneously characters and graphical elements, the <EM>symbols</EM>. By way
! 367: of example, Radicals, integration signs, or even large parentheses are
! 368: examples of this type of atom. The size of each of these symbols is
! 369: determined by its environment, that is to say, by the expression to which it
! 370: is attached.</P>
! 371: <P>
! 372: To summarize, the primitive elements which are used in the construction of
! 373: documents and structured objects are:</P>
! 374: <UL>
! 375: <LI>character strings,
! 376: <LI>graphical elements,
! 377: <LI>images,
! 378: <LI>and mathematical symbols.
! 379: </UL>
! 380: </DIV>
! 381:
! 382: <DIV class="subsection">
! 383: <H3>Constructed elements</H3>
! 384:
! 385: <P>
! 386: A document is evidently formed from primitive elements. But the model of Thot
! 387: also proposes higher level elements. Thus, in a document composed of several
! 388: chapters, each chapter is an element, and in the chapters each section is also
! 389: an element, and so on. A document is thus an organized set of elements.</P>
! 390: <P>
! 391: In a document there are different sorts of elements. Each element has a
! 392: <EM>type</EM> which indicates the role of the element within the document as a
! 393: whole. Thus, we have, for example, the chapter and section types. The
! 394: document is made up of typed elements: elements of the type chapter and
! 395: elements of the type section, among others, but also character string elements
! 396: and graphical elements: the primitive elements are typed elements just as
! 397: well. At the other extreme, the document itself is also considered to be a
! 398: typed element.</P>
! 399: <P>
! 400: The important difference between the primitive elements and the other elements
! 401: of the document is that the primitive elements are atoms (they cannot be
! 402: decomposed), whereas the others, called <EM>constructed elements</EM>, are
! 403: composed of other elements, which can either be primitive elements or
! 404: constructed elements. A constructed element of type chapter (or more simply,
! 405: ``a chapter'') is composed of sections, which are also constructed elements. A
! 406: paragraph, a constructed element, can be made up of character strings, which
! 407: are primitive elements, and of equations, which are constructed elements.</P>
! 408: <P>
! 409: A parallel can be made between the element types and the data types of
! 410: programming languages, such as C. The four primitive types of Thot are
! 411: comparable to the standard primitive types of C: integer, character, and real,
! 412: for instance. The types of constructed elements are comparable to the
! 413: structured types of C which each programmer defines from the primitive
! 414: types.</P>
! 415: <P>
! 416: A document is also a constructed element. This is an important point. In
! 417: particular, it allows a document to be treated as part of another document,
! 418: and conversely, permits a part of a document to be treated as a complete
! 419: document. Thus, an article presented in a journal is treated by its author as
! 420: a document in itself, while the editor of the journal considers it to be part
! 421: of an issue. A table or a figure appearing in a document can be extracted and
! 422: treated as a complete document, for example to prepare transparencies for a
! 423: conference.</P>
! 424: <P>
! 425: These thoughts about types and constructed elements apply just as well to
! 426: objects as they do to documents. A table is a constructed element made up of
! 427: other constructed elements, rows and columns. A row is formed of cells, which
! 428: are also constructed elements which contain primitive elements (character
! 429: strings) and/or constructed elements like equations.</P>
! 430: </DIV>
! 431:
! 432: <DIV class="subsection">
! 433: <H3>Logical structure constructors</H3>
! 434:
! 435: <P>
! 436: Having defined the primitive elements and the constructed elements, it is now
! 437: time to define the types of organization which allow the building of
! 438: structures. For this, we rely on the notion of the <EM>constructor</EM>. A
! 439: constructor defines a way of assembling certain elements in a structure. It
! 440: resides at the level of the meta-structure: it does not describe the existing
! 441: relations in a given structure, but rather defines how elements are assembled
! 442: to build a structure that conforms to a model. In comparison with C, the
! 443: constructors correspond to the methods for building structured data types:
! 444: arrays and structures.</P>
! 445: <P>
! 446: In defining the overall organization of documents, the first two constructors
! 447: considered are the aggregate and the list.</P>
! 448:
! 449: <DIV class="subsubsection">
! 450: <H4>Aggregate and List</H4>
! 451:
! 452: <P>
! 453: The <EM>aggregate</EM> constructor is used to define constructed element types
! 454: which are collections of a given number of other elements. These collections
! 455: may or may not be ordered. The elements may be either constructed or
! 456: primitive and are specified by their type. A report (that is, a constructed
! 457: element of the report type) has an aggregate structure. It is formed from a
! 458: title, an author's name, an introduction, a body, and a conclusion, making it
! 459: a collection of five element types. This type of constructor is found in
! 460: practically every document, and generally at several levels in a document.</P>
! 461: <P>
! 462: The <EM>list</EM> constructor is used to define constructed elements which are
! 463: ordered sequences of elements (constructed or primitive) having the same type.
! 464: The minimum and maximum numbers of elements for the sequence can be specified
! 465: in the list constructor or the number of elements can be left unconstrained.
! 466: The body of a report is a list of chapters and is typically required to
! 467: contain a minimum of two chapters (is a chapter useful if it is the only one
! 468: in the report?) The chapter itself can contain a list of sections, each
! 469: section containing a list of paragraphs. The list constructor corresponds to
! 470: a one-dimensional array in C. In the same way as the aggregate, the list is a
! 471: very frequently used constructor in every type of document. However, these
! 472: two constructors are not sufficient to describe every document structure; thus
! 473: other constructors supplement them.</P>
! 474: </DIV>
! 475:
! 476: <DIV class="subsubsection">
! 477: <H4><A name="schemasandunits">Choice, Schema, and Unit</A></H4>
! 478:
! 479: <P>
! 480: The <EM>choice</EM> constructor is used to define the structure of an element
! 481: type for which one alternative is chosen from several possibilities. Thus, a
! 482: paragraph can be either a simple text paragraph, or an enumeration, or a
! 483: citation. The choice constructor can be compared to the variant parts of
! 484: structures in C.</P>
! 485: <P>
! 486: The choice constructor indicates the complete list of possible options, which
! 487: can be too restrictive in certain cases, the paragraph being one such case.
! 488: Two constructors, <EM>unit</EM> and <EM>schema</EM>, address this
! 489: inconvenience. They allow more freedom in the choice of an element type. If
! 490: a paragraph is defined by a schema constructor, it is possible to put in the
! 491: place of a paragraph a table, an equation, a drawing or any other object
! 492: defined by another generic logical structure. It is also possible to define a
! 493: paragraph as a sequence of units, which could be character strings, symbols,
! 494: or images. The choice constructor alone defines a generic logical structure
! 495: that is relatively constrained; in contrast, using units and schemas, a very
! 496: open structure can be defined.</P>
! 497: <P>
! 498: The <EM>schema</EM> constructor represents an object defined by a generic
! 499: logical structure chosen freely from among those available.</P>
! 500: <P>
! 501: The <EM>unit</EM> constructor represents an element whose type can be either a
! 502: primitive type or an element type defined as a unit in the generic logical
! 503: structure of the document, or in another generic logical structure used in the
! 504: document. Such an element may be used in document objects constructed
! 505: according to other generic structures.</P>
! 506: <P>
! 507: Thus, for example, if a cross-reference to a footnote is defined in the
! 508: generic logical structure ``Article'' as a unit, a table (an object defined by
! 509: another generic structure) can contain cross-references to footnotes, when
! 510: they appear in an article. In another type of document, a table defined by
! 511: the same generic structure can contain other types of elements, depending on
! 512: the type of document into which the table is inserted. All that is needed is
! 513: to declare, in the generic structure for tables, that the contents of cells
! 514: are units. In this way, the generic structure of objects is divided up
! 515: between different types of documents which are able to adapt themselves to the
! 516: environment into which they are inserted.</P>
! 517: </DIV>
! 518:
! 519: <DIV class="subsubsection">
! 520: <H4>Reference and Inclusion</H4>
! 521:
! 522: <P>
! 523: The <EM>reference</EM> is the last constructor. It is used to define document
! 524: elements that are cross-references to other elements, such as a section, a
! 525: chapter, a bibliographic citation, or a figure. The reference can be compared
! 526: to the pointer in C, but in contrast to the pointer, the reference is
! 527: bi-directional. The reference can be used to access both the element being
! 528: cross-referenced and each of the elements which make use of the
! 529: cross-reference.</P>
! 530: <P>
! 531: References can be either <EM>internal</EM> or <EM>external</EM>. That is,
! 532: they can designate elements which appear in the same document or in another
! 533: document.</P>
! 534: <P>
! 535: The <EM><A name="inclusion">inclusion</A></EM> constructor is a special type
! 536: of reference. Like the reference, it is an internal or external bidirectional
! 537: link, but it is not a cross-reference. This link represents the ``live''
! 538: inclusion of the designated element; it accesses the most recent version of
! 539: that element and not a ``dead'' copy, fixed in the state in which it was found
! 540: at the moment the copy was made. As soon as an element is modified, all of
! 541: its inclusions are automatically brought up to date. It must be noted that,
! 542: in addition to inclusion, the Thot editor permits the creation of ``dead''
! 543: copies.</P>
! 544: <P>
! 545: There are three types of inclusions: inclusions with full expansion,
! 546: inclusions with partial expansion, and inclusions without expansion. During
! 547: editing, inclusions without expansion are represented on the screen by the
! 548: name of the included document, in a special color, while inclusions with
! 549: expansion (full or partial) are represented by a copy (full or partial) of the
! 550: included element (also in a special color). The on-screen representation of a
! 551: partial inclusion is a <A href="#skeleton">``skeleton''</A> image of the
! 552: included document.</P>
! 553: <P>
! 554: Inclusion with complete expansion can be used to include parts of the same
! 555: document or of other documents. Thus, it can be either an internal or an
! 556: external link. It can be used to include certain bibliographic entries of a
! 557: scientific article in another article, or to copy part of a mathematical
! 558: formula into another formula of the same document, thus assuring that both
! 559: copies will remain synchronized.</P>
! 560: <P>
! 561: Inclusion without expansion or with partial expansion is used to include
! 562: complete documents. It is always an external link. It is used primarily to
! 563: divide very large documents into sub-documents that are easier to manipulate,
! 564: especially when there are many authors. So, a book can include some chapters,
! 565: where each chapter is a different document which can be edited separately.
! 566: When viewing the book on the screen, it might be desirable to see only the
! 567: titles of the chapters and sections. This can be achieved using inclusion
! 568: with partial expansion.</P>
! 569: <P>
! 570: During printing, inclusions without expansion or with partial expansion can be
! 571: represented either as they were shown on the screen or by a complete (and
! 572: up-to-date) copy of the included element or document.</P>
! 573: <P>
! 574: The inclusion constructor, whatever its type, respects the generic structure:
! 575: only those elements authorized by the generic structure can be included at a
! 576: given position in a document.</P>
! 577: </DIV>
! 578:
! 579: <DIV class="subsubsection">
! 580: <H4>Mark pairs</H4>
! 581:
! 582: <P>
! 583: It is often useful to delimit certain parts of a document independently from
! 584: the logical structure. For example, one might wish to attach some information
! 585: (in the form of an <A href="#attributes">attribute,</A>) or a particular
! 586: treatment to a group of words or a set of consecutive paragraphs. <EM>Mark
! 587: pairs</EM> are used to do this.</P>
! 588: <P>
! 589: Mark pairs are elements which are always paired and are terminals in the
! 590: logical structure of the document. Their position in the structure of the
! 591: document is defined in the generic structure. It is important to note that
! 592: when the terminals of a mark pair are <EM>extensions</EM> (see the next
! 593: section), they can be used quite freely.</P>
! 594: </DIV>
! 595:
! 596: <DIV class="subsubsection">
! 597: <H4><A name="restrictionextensions">Restrictions and Extensions</A></H4>
! 598:
! 599: <P>
! 600: The primitive types and the constructors presented so far permit the
! 601: definition of the logical structure of documents and objects in a rigorous
! 602: way. But this definition can be very cumbersome in certain cases, notably
! 603: when trying to constrain or extend the authorized element types in a
! 604: particular context. <EM>Restrictions</EM> and <EM>extensions</EM> are used to
! 605: simplify these cases.</P>
! 606: <P>
! 607: A restriction associates with a particular element type <EM>A</EM>, a list of
! 608: those element types which elements of type <EM>A</EM> may not contain, even if
! 609: the definition of type <EM>A</EM> and those of its components authorize them
! 610: otherwise. This simplifies the writing of generic logical structures and
! 611: allows limitations to be placed, when necessary, on the choices offered by the
! 612: schema and unit constructors.</P>
! 613: <P>
! 614: Extensions are the inverse of restrictions. They identify a list of element
! 615: types whose presence <EM>is</EM> permitted, even if its definition and those
! 616: of its components do not authorize them otherwise.</P>
! 617: </DIV>
! 618:
! 619: <DIV class="subsubsection">
! 620: <H4>Summary</H4>
! 621:
! 622: <P>
! 623: Thus, four constructors are used to construct a document:</P>
! 624: <UL>
! 625: <LI>the aggregate constructor,
! 626: <LI>the list constructor,
! 627: <LI>the choice constructor and its extensions, the unit and
! 628: schemaconstructors,
! 629: <LI>the reference constructor and its variant, the inclusion.
! 630: </UL>
! 631: <P>
! 632: These constructors are also sufficient for objects. Thus, these constructors
! 633: provide a homogenous meta-model which can describe both the organization of
! 634: the document as a whole and that of the various types of objects which it
! 635: contains. After presenting the description language for generic structures,
! 636: we will present several examples which illustrate the appropriateness of the
! 637: model.</P>
! 638: <P>
! 639: The first three constructors (aggregate, list and choice) lead to tree-like
! 640: structures for documents and objects, the objects being simply the subtrees of
! 641: the tree of a document (or even of other objects' subtrees). The reference
! 642: constructor introduces other, non-hierarchical, relations which augment those
! 643: of the tree: when a paragraph makes reference to a chapter or a section, that
! 644: relation leaves the purely tree-like structure. Moreover, external reference
! 645: and inclusion constructors permit the establishment of links between different
! 646: documents, thus creating a hypertext structure.</P>
! 647: </DIV>
! 648: </DIV>
! 649:
! 650: <DIV class="subsection">
! 651: <H3><A name="assocelem">Associated Elements</A></H3>
! 652:
! 653: <P>
! 654: Thanks to the list, aggregate and choice constructors, the organization of the
! 655: document is specified rigorously, using constructed and primitive elements.
! 656: But a document is made up of more than just its elements; it clearly also
! 657: contains links between them. There exist elements whose position in the
! 658: document's structure is not determinable. This is notably the case for
! 659: figures and notes. A figure can be designated at many points in the same
! 660: document and its place in the physical document can vary over the life of the
! 661: document without any effect on the meaning or clarity of the document. At one
! 662: time, it can be placed at the end of the document along with all other
! 663: figures. At another time, it can appear at the top of the page which follows
! 664: the first mention of the figure. The figures can be dispersed throughout the
! 665: document or can be grouped together. The situation is similar for notes,
! 666: which can be printed at the bottom of the page on which they are mentioned or
! 667: assembled together at the end of the chapter or even the end of the work. Of
! 668: course, this brings up questions of the physical position of elements in
! 669: documents that are broken into pages, but this reflects the structural
! 670: instability of these elements. They cannot be treated the same way as
! 671: elements like paragraphs or sections, whose position in the structure is
! 672: directly linked to the semantics of the document.</P>
! 673: <P>
! 674: Those elements whose position in the structure of the document is not fixed,
! 675: even though they are definitely part of the document, are called
! 676: <EM>associated elements</EM>. Associated elements are themselves structures,
! 677: which is to say that their content can be organized logically by the
! 678: constructors from primitive and constructed elements.</P>
! 679: <P>
! 680: It can happen that the associated elements are totally disconnected from the
! 681: structure of the document, as in a commentary or appraisal of the entire work.
! 682: But more often, the associated elements are linked to the content of the
! 683: document by references. This is generally the case for notes and figures,
! 684: among others.</P>
! 685: <P>
! 686: Thus, associated elements introduce a new use for the reference constructor.
! 687: It not only serves to create links between elements of the principal structure
! 688: of the document, but also serves to link the associated elements to the
! 689: primary structure.</P>
! 690: </DIV>
! 691:
! 692: <DIV class="subsection">
! 693: <H3><A name="attributes">Attributes</A></H3>
! 694:
! 695: <P>
! 696: There remain logical aspects of documents that are not entirely described by
! 697: the structure. Certain types of semantic information, which are not stated
! 698: explicitly in the text, must also be taken into account. In particular, such
! 699: information is shown by typographic effects which do not correspond to a
! 700: change between structural elements. In fact, certain titles are set in bold
! 701: or italic or are printed in a different typeface from the rest of the text in
! 702: order to mark them as structurally distinct. But these same effects
! 703: frequently appear in the middle of continuous text (e.g. in the interior of a
! 704: paragraph). In this case, there is no change between structural elements; the
! 705: effect serves to highlight a word, expression, or phrase. The notion of an
! 706: <EM>attribute</EM> is used to express this type of information.</P>
! 707: <P>
! 708: An attribute is a piece of information attached to a structural element which
! 709: augments the type of the element and clarifies its function in the document.
! 710: Keywords, foreign language words, and titles of other works can all be
! 711: represented by character strings with attached attributes. Attributes may
! 712: also be attached to constructed elements. Thus, an attribute indicating the
! 713: language can be attached to a single word or to a large part of a
! 714: document.</P>
! 715: <P>
! 716: In fact, an attribute can be any piece of information which is linked to a
! 717: part of a document and which can be used by agents which work on the document.
! 718: For example, the language in which the document is written determines the set
! 719: of characters used by an editor or formatter. It also determines the
! 720: algorithm or hyphenation dictionary to be used. The attribute ``keyword''
! 721: facilitates the work of an information retrieval system. The attribute
! 722: ``index word'' allows a formatter to automatically construct an index at the
! 723: end of the document.</P>
! 724: <P>
! 725: As with the types of constructed elements, the attributes and the values they
! 726: can take are defined separately in each generic logical structure, not in the
! 727: meta-model, according to the needs of the document class or the nature of the
! 728: object.</P>
! 729: <P>
! 730: Many types of attributes are offered: numeric, textual, references, and
! 731: enumerations:</P>
! 732: <UL>
! 733: <LI><EM>Numeric attributes</EM> can take integer values (negative,positive, or
! 734: null).
! 735: <LI><EM>Textual attributes</EM> have as their values character strings.
! 736: <LI><EM>Reference attributes</EM> designate an element of the
! 737: logicalstructure.
! 738: <LI><EM>Enumeration attributes</EM> can take one value from a limitedlist of
! 739: possible values, each value being a name.
! 740: </UL>
! 741: <P>
! 742: In a generic structure, there is a distinction between <EM>global
! 743: attributes</EM> and <EM>local attributes</EM>. A global attribute can be
! 744: applied to every element type defined in the generic structure where it is
! 745: specified. In contrast, a local attribute can only be applied to certain
! 746: types of elements, even only a single type. The ``language'' attribute
! 747: presented above is an example of a global attribute. An example of a local
! 748: attribute is the rank of an author (principal author of the document or
! 749: secondary author): this attribute can only be applied sensibly to an element
! 750: of the ``author'' type.</P>
! 751: <P>
! 752: Attributes can be assigned to the elements which make up the document in many
! 753: different ways. The author can freely and dynamically place them on any part
! 754: of the document in order to attach supplementary information of his choice.
! 755: However, attributes may only be assigned in accordance with the rules of the
! 756: generic structure; in particular, local attributes can only be assigned to
! 757: those element types for which they are defined.</P>
! 758: <P>
! 759: In the generic structure, certain local attributes can be made mandatory for
! 760: certain element types. In this case, the Thot editor automatically associates
! 761: the attribute with the elements of this type and it requires the user to
! 762: provide a value for this attribute.</P>
! 763: <P>
! 764: Attributes can also be automatically assigned, with a given value, by every
! 765: application processing the document in order to systematically add a piece of
! 766: information to certain predefined elements of the document. By way of
! 767: example, in a report containing a French abstract and an English abstract,
! 768: each of the two abstracts is defined as a sequence of paragraphs. The first
! 769: abstract has a value of ``French'' for the ``language'' attribute while the
! 770: second abstract's ``language'' attribute has a value of ``English''.</P>
! 771: <P>
! 772: In the case of mark pairs, attributes are logically associated with the pair
! 773: as a whole, but are actually attached to the first mark.</P>
! 774: </DIV>
! 775:
! 776: <DIV class="subsection">
! 777: <H3>Discussion of the model</H3>
! 778:
! 779: <P>
! 780: The notions of attribute, constructor, structured element, and associated
! 781: element are used in the definition of generic logical structures of documents
! 782: and objects. The problem is to assemble them to form generic structures. In
! 783: fact, many types of elements and attributes can be found in a variety of
! 784: generic structures. Rather than redefine them for each structure in which
! 785: they appear, it is best to share them between structures. The object classes
! 786: already fill this sharing function. If a mathematical class is defined, its
! 787: formulas can be used in many different document classes, without redefining
! 788: the structure of each class. This problem arises not only for the objects
! 789: considered here; it also arises for the commonplace textual elements found in
! 790: many document classes. This is the reason why the notion of object is so
! 791: broad and why paragraphs and enumerations are also considered to be objects.
! 792: These object classes not only permit the sharing of the structures of
! 793: elements, but also of the attributes defined in the generic structures.</P>
! 794: <P>
! 795: Structure, such as that presented here, can appear very rigid, and it is
! 796: possible to imagine that a document editing system based on this model could
! 797: prove very constraining to the user. This is, in fact, a common criticism of
! 798: syntax-directed editors. This defect can be avoided with Thot, primarily for
! 799: three reasons:</P>
! 800: <UL>
! 801: <LI>the generic structures are not fixed in the model itself,
! 802: <LI>the model takes the dynamics of documents into account,
! 803: <LI>the constructors offer great flexibility.
! 804: </UL>
! 805: <P>
! 806: When the generic structure of a document is not predefined, but rather is
! 807: constructed specifically for each document class, it can be carefully adapted
! 808: to the current needs. In cases where the generic structure is inadequate for
! 809: a particular document of the class, it is always possible either to create a
! 810: new class with a generic structure well suited to the new case or to extend
! 811: the generic structure of the existing class to take into account the specifics
! 812: of the document which poses the problem. These two solutions can also be
! 813: applied to objects whose structures prove to be poorly designed.</P>
! 814: <P>
! 815: The model is sufficiently flexible to take into account all the phases of the
! 816: life of the document. When a generic structure specifies that a report must
! 817: contain a title, an abstract, an introduction, at least two chapters, and a
! 818: conclusion, this means only that a report, <EM>upon completion</EM>, will have
! 819: to contain all of these elements. When the author begins writing, none of
! 820: these elements is present. The Thot editor uses this model. Therefore, it
! 821: tolerates documents which do not conform strictly to the generic structure of
! 822: their class; it also considers the generic logical structure to be a way of
! 823: helping the user in the construction of a complex document.</P>
! 824: <P>
! 825: In contrast, other applications may reject a document which does not conform
! 826: strictly to its generic structure. This is, for example, what is done by
! 827: compilers which refuse to generate code for a program which is not
! 828: syntactically correct. This might also occur when using a document
! 829: application for a report which does not have an abstract or title.</P>
! 830: <P>
! 831: The constructors of the document model bring a great flexibility to the
! 832: generic structures. A choice constructor (and even more, a unit or schema
! 833: constructor) can represent several, very different elements. The list
! 834: constructor permits the addition of more elements of the same type. Used
! 835: together, these two constructors permit any series of elements of different
! 836: types. Of course, this flexibility can be reduced wherever necessary since a
! 837: generic structure can limit the choices or the number of elements in a
! 838: list.</P>
! 839: <P>
! 840: Another difficulty linked to the use of structure in the document model
! 841: resides in the choice of the level of the structure. The structure of a
! 842: discussion could be extracted from the text itself via linguistic analysis.
! 843: Some studies are exploring this approach, but the model of Thot excludes this
! 844: type of structure. It only takes into account the logical structure provided
! 845: explicitly by the author.</P>
! 846: <P>
! 847: However, the level of structure of the model is not imposed. Each generic
! 848: structure defines its own level of structure, adapted to the document class or
! 849: object and to the ways in which it will be processed. If it will only be
! 850: edited and printed, a relatively simple structure suffices. If more
! 851: specialized processing will be applied to it, the structure must represent the
! 852: element types on which this processing must act. By way of example, a simple
! 853: structure is sufficient for printing formulas, but a more complex structure is
! 854: required to perform symbolic or numeric calculations on the mathematical
! 855: expressions. The document model of Thot allows both types of structure.</P>
! 856: </DIV>
! 857: </DIV>
! 858:
! 859: <DIV class="section">
! 860: <H2>The definition language for generic structures</H2>
! 861:
! 862: <P>
! 863: Generic structures, which form the basis of the document model of Thot, are
! 864: specified using a special language. This definition language, called S, is
! 865: described in this section.</P>
! 866: <P>
! 867: Each generic structure, which defines a class of documents or objects, is
! 868: specified by a kind of program, written in the S language, which is called a
! 869: <EM>structure schema</EM>. Structure schemas are compiled into tables, called
! 870: structure tables, which are used by the Thot editor and which determine its
! 871: behavior.</P>
! 872:
! 873: <DIV class="subsection">
! 874: <H3><A name="metalang">Writing Conventions</A></H3>
! 875:
! 876: <P>
! 877: The grammar of S, like those of the languages P and T presented later, is
! 878: described using the meta-language M, derived from the Backus-Naur Form
! 879: (BNF).</P>
! 880: <P>
! 881: In this meta-language each rule of the grammar is composed of a grammar symbol
! 882: followed by an equals sign (`=') and the right part of the rule. The equals
! 883: sign plays the same role as the traditional `::=' of BNF: it indicates that
! 884: the right part defines the symbol of the left part. In the right part,</P>
! 885: <DL>
! 886: <DT>concatenation</DT>
! 887: <DD>is shown by the juxtaposition of symbols;
! 888: </DD>
! 889: <DT>character strings</DT>
! 890: <DD>between apostrophes ' represent terminalsymbols, that is, keywords in the
! 891: language defined. Keywords arewritten here in upper-case letters, but can be
! 892: written in anycombination of upper and lower-case letters. For example, the
! 893: keyword<TT>DEFPRES</TT>of S can also be written as
! 894: <TT>defpres</TT>or<TT>DefPres</TT>.
! 895: </DD>
! 896: <DT>material between brackets</DT>
! 897: <DD>(`[' and `]') is optional;
! 898: </DD>
! 899: <DT>material between angle brackets</DT>
! 900: <DD>(`<' and `>') can be repeatedmany times or omitted;
! 901: </DD>
! 902: <DT>the slash</DT>
! 903: <DD>(`/') indicates an alternative, a choice between theoptions separated by
! 904: the slash character;
! 905: </DD>
! 906: <DT>the period</DT>
! 907: <DD>marks the end of a rule;
! 908: </DD>
! 909: <DT>text between braces</DT>
! 910: <DD>(`{' and `}') is simply a comment.
! 911: </DD>
! 912: </DL>
! 913: <P>
! 914: The M meta-language also uses the concepts of identifiers, strings, and
! 915: integers:</P>
! 916: <DL>
! 917: <DT><TT>NAME</TT></DT>
! 918: <DD>represents an identifier, a sequence of letters(upper or lower-case),
! 919: digits, and underline characters (`_'),beginning with a letter. Also
! 920: considered a letter is the sequence ofcharacters `<TT>\nnn</TT>' where the
! 921: letter <TT>n</TT>represents the ISOLatin 1 code of the letter in octal. It is
! 922: thus possible to useaccented letters in identifiers. The maximum length of
! 923: identifiersis fixed by the compiler. It is normally 19 characters.
! 924: <P>
! 925: Unlike keywords, upper and lower-case letters are distinct in identifiers.
! 926: Thus, <TT>Title</TT>, <TT>TITLE</TT>, and <TT>title</TT> are considered
! 927: different identifiers.</P>
! 928: </DD>
! 929: <DT><TT>STRING</TT></DT>
! 930: <DD>represents (amazingly enough) a string. This is astring of characters
! 931: delimited by apostrophes. If an apostrophe mustappear in a string, it is
! 932: doubled. As with identifiers, strings cancontain characters represented by
! 933: their octal code (after abackslash). As with apostrophes, if a backslash must
! 934: appear in astring, it is doubled.
! 935: </DD>
! 936: <DT><TT>NUMBER</TT></DT>
! 937: <DD>represents a positive integer or zero (without asign), or said another
! 938: way, a sequence of decimal digits.
! 939: </DD>
! 940: </DL>
! 941: <P>
! 942: The M language can be used to define itself as follows:</P>
! 943: <PRE>
! 944: { Any text between braces is a comment. }
! 945: Grammar = Rule < Rule > 'END' .
! 946: { The < and > signs indicate zero }
! 947: { or more repetitions. }
! 948: { END marks the end of the grammar. }
! 949: Rule = Ident '=' RightPart '.' .
! 950: { The period indicates the end of a rule }
! 951: RightPart = RtTerminal / RtIntermed .
! 952: { The slash indicates a choice }
! 953: RtTerminal ='NAME' / 'STRING' / 'NUMBER' .
! 954: { Right part of a terminal rule }
! 955: RtIntermed = Possibility < '/' Possibility > .
! 956: { Right part of an intermediate rule }
! 957: Possibility = ElemOpt < ElemOpt > .
! 958: ElemOpt = Element / '[' Element < Element > ']' /
! 959: '<' Element < Element > '>' .
! 960: { Brackets delimit optional parts }
! 961: Element = Ident / KeyWord .
! 962: Ident = NAME .
! 963: { Identifier, sequence of characters }
! 964: KeyWord = STRING .
! 965: { Character string delimited by apostrophes }
! 966: END
! 967: </PRE>
! 968: </DIV>
! 969:
! 970: <DIV class="subsection">
! 971: <H3><A name="extsch">Extension schemas</A></H3>
! 972:
! 973: <P>
! 974: A structure schema defines the generic logical structure of a class of
! 975: documents or objects, independent of the operations which can be performed on
! 976: the documents. However, certain applications may require particular
! 977: information to be represented by the structure for the documents that they
! 978: operate on. Thus a document version manager will need to indicate in the
! 979: document the parts which belong to one version or another. An indexing system
! 980: will add highly-structured index tables as well as the links between these
! 981: tables and the rest of the document.</P>
! 982: <P>
! 983: Thus, each application needs to extend the generic structure of the documents
! 984: on which it operates to introduce new attributes, associated elements or
! 985: element types. These additions are specific to each application and must be
! 986: able to be applied to any generic structure: users will want to manage
! 987: versions or construct indices for many types of documents. Extension schemas
! 988: fulfill this role: they define attributes, elements, associated elements,
! 989: units, etc., but they can only be used jointly with a structure schema that
! 990: they complete. Otherwise, structure schemas can always be used without these
! 991: extensions when the corresponding applications are not available.</P>
! 992: </DIV>
! 993:
! 994: <DIV class="subsection">
! 995: <H3>The general organization of structure schemas</H3>
! 996:
! 997: <P>
! 998: Every structure schema begins with the keyword <TT>STRUCTURE</TT> and ends
! 999: with the keyword <TT>END</TT>. The keyword <TT>STRUCTURE</TT> is followed by
! 1000: the keyword <TT>EXTENSION</TT> in the case where the schema defines an
! 1001: extension, then by the name of the generic structure which the schema defines
! 1002: (the name of the document or object class). The name of the structure is
! 1003: followed by a semicolon.</P>
! 1004: <P>
! 1005: In the case of a complete schema (that is, a schema which is not an
! 1006: extension), the definition of the name of the structure is followed by the
! 1007: declarations of the default presentation schema, the global attributes, the
! 1008: parameters, the structure rules, the associated elements, the units, the
! 1009: skeleton elements and the exceptions. Only the definition of the structure
! 1010: rules is required. Each series of declarations begins with a keyword:
! 1011: <TT>DEFPRES</TT>, <TT>ATTR</TT>, <TT>PARAM</TT>, <TT>STRUCT</TT>,
! 1012: <TT>ASSOC</TT>, <TT>UNITS</TT>, <TT>EXPORT</TT>, <TT>EXCEPT</TT>.</P>
! 1013: <P>
! 1014: In the case of an extension schema, there are neither parameters nor skeleton
! 1015: elements and the <TT>STRUCT</TT> section is optional, while that section is
! 1016: required in a schema that is not an extension. On the other hand, extension
! 1017: schemas can contain an <TT>EXTENS</TT> section, which must not appear in a
! 1018: schema which is not an extension; this section defines the complements to
! 1019: attach to the rules found in the schema to which the extension will be added.
! 1020: The sections <TT>ATTR</TT>, <TT>STRUCT</TT>, <TT>ASSOC</TT>, and
! 1021: <TT>UNITS</TT> define new attributes, new elements, new associated elements,
! 1022: and new units which add their definitions to the principal schema.</P>
! 1023: <PRE>
! 1024: StructSchema ='STRUCTURE' ElemID ';'
! 1025: 'DEFPRES' PresID ';'
! 1026: [ 'ATTR' AttrSeq ]
! 1027: [ 'PARAM' RulesSeq ]
! 1028: 'STRUCT' RulesSeq
! 1029: [ 'ASSOC' RulesSeq ]
! 1030: [ 'UNITS' RulesSeq ]
! 1031: [ 'EXPORT' SkeletonSeq ]
! 1032: [ 'EXCEPT' ExceptSeq ]
! 1033: 'END' .
! 1034: ElemID = NAME .
! 1035: </PRE>
! 1036: <P>
! 1037: or</P>
! 1038: <PRE>
! 1039: ExtensSchema ='STRUCTURE' 'EXTENSION' ElemID ';'
! 1040: 'DEFPRES' PresID ';'
! 1041: [ 'ATTR' AttrSeq ]
! 1042: [ 'STRUCT' RulesSeq ]
! 1043: [ 'EXTENS' ExtensRuleSeq ]
! 1044: [ 'ASSOC' RulesSeq ]
! 1045: [ 'UNITS' RulesSeq ]
! 1046: [ 'EXCEPT' ExceptSeq ]
! 1047: 'END' .
! 1048: ElemID = NAME .
! 1049: </PRE>
! 1050: </DIV>
! 1051:
! 1052: <DIV class="subsection">
! 1053: <H3>The default presentation</H3>
! 1054:
! 1055: <P>
! 1056: It was shown <A href="#mulpres">above</A> that many different presentations
! 1057: are possible for documents and objects of the same class. The structure
! 1058: schema defines a preferred presentation for the class, called the <EM>default
! 1059: presentation</EM>. Like generic structures, presentations are described by
! 1060: programs, called <EM>presentation schemas</EM>, which are written in a
! 1061: specific language, P, presented <A href="#langp">later</A> in this document.
! 1062: The name appearing after the keyword <TT>DEFPRES</TT> is the name of the
! 1063: default presentation schema. When a new document is created, the Thot editor
! 1064: will suggest using this presentation schema, but the user remains free to
! 1065: choose another if he wishes.</P>
! 1066: <PRE>
! 1067: PresID = NAME .
! 1068: </PRE>
! 1069: </DIV>
! 1070:
! 1071: <DIV class="subsection">
! 1072: <H3><A name="globalattr">Global Attributes</A></H3>
! 1073:
! 1074: <P>
! 1075: If the generic structure includes global attributes of its own, they are
! 1076: declared after the keyword <TT>ATTR</TT>. Each global attribute is defined by
! 1077: its name, followed by an equals sign and the definition of its type. The
! 1078: declaration of a global attribute is terminated by a semi-colon.</P>
! 1079: <P>
! 1080: For attributes of the numeric, textual, or reference types, the type is
! 1081: indicated by a keyword, <TT>INTEGER</TT>, <TT>TEXT</TT>, or <TT>REFERENCE</TT>
! 1082: respectively.</P>
! 1083: <P>
! 1084: In the case of a reference attribute, the keyword <TT>REFERENCE</TT> is
! 1085: followed by the type of the referenced element in parentheses. It can refer
! 1086: to any type at all, specified by using the keyword <TT>ANY</TT>, or to a
! 1087: specific type. In the latter case, the element type designated by the
! 1088: reference can be defined either in the <A href="#structelem"><TT>STRUCT</TT>
! 1089: section</A> of the same structure schema or in the <TT>STRUCT</TT> section of
! 1090: another structure schema. When the type is defined in another schema, the
! 1091: element type is followed by the name of the structure schema (within
! 1092: parentheses) in which it is defined. The name of the designated element type
! 1093: can be preceded by the keyword <TT>First</TT> or <TT>Second</TT>, but only in
! 1094: the case where the type is defined as <A href="#pairs">a pair</A>. The
! 1095: keywords indicate whether the attribute must designate the first mark of the
! 1096: pair or the second. If the reference refers to a pair and neither of these
! 1097: two keywords is present, then the first mark is used.</P>
! 1098: <P>
! 1099: In the case of an enumeration attribute, the equals sign is followed by the
! 1100: list of names representing the possible values of the attribute, the names
! 1101: being separated from each other by commas. An enumeration attribute has at
! 1102: least one possible value; the maximum number of values is defined by the
! 1103: compiler for the S language.</P>
! 1104: <PRE>
! 1105: AttrSeq = Attribute < Attribute > .
! 1106: Attribute = AttrID '=' AttrType ';' .
! 1107: AttrType = 'INTEGER' / 'TEXT' /
! 1108: 'REFERENCE' '(' RefType ')' /
! 1109: ValueSeq .
! 1110: RefType = 'ANY' / [ FirstSec ] ElemID [ ExtStruct ] .
! 1111: FirstSec = 'First' / 'Second' .
! 1112: ExtStruct = '(' ElemID ')' .
! 1113: ValueSeq = AttrVal < ',' AttrVal > .
! 1114: AttrID = NAME .
! 1115: AttrVal = NAME .
! 1116: </PRE>
! 1117: <P>
! 1118: There is a predefined global text attribute, the <EM>language</EM>, which is
! 1119: automatically added to every Thot structure schema. This attribute allows the
! 1120: editor to perform certain actions, such as hyphenation and spell-checking,
! 1121: which cannot be performed without knowing the language in which each part of
! 1122: the document is written. This attribute can be used just like any explicitly
! 1123: declared attribute: the system acts as if every structure schema contains</P>
! 1124: <PRE>
! 1125: ATTR
! 1126: Language = TEXT;
! 1127: </PRE>
! 1128: <BLOCKQUOTE class="example">
! 1129: <P>
! 1130: <STRONG>Example:</STRONG></P>
! 1131: <P>
! 1132: The following specification defines the global enumeration
! 1133: attributeWordType.</P>
! 1134: <PRE>
! 1135: ATTR
! 1136: WordType = Definition, IndexWord, DocumentTitle;
! 1137: </PRE>
! 1138: </BLOCKQUOTE>
! 1139: </DIV>
! 1140:
! 1141: <DIV class="subsection">
! 1142: <H3><A name="param">Parameters</A></H3>
! 1143:
! 1144: <P>
! 1145: A parameter is a document element which can appear many times in the document,
! 1146: but always has the same value. This value can only be modified in a
! 1147: controlled way by certain applications. For example, in an advertising
! 1148: circular, the name of the recipient may appear in the address part and in the
! 1149: text of the circular. If the recipient's name were a parameter, it might only
! 1150: be able to be changed by a ``mail-merge'' application.</P>
! 1151: <P>
! 1152: Parameters are not needed for every document class, but if the schema includes
! 1153: parameters they are declared after the keyword <TT>PARAM</TT>. Each parameter
! 1154: declaration is made in the same way as a <A href="#structelem">structure
! 1155: element declaration</A>.</P>
! 1156: <P>
! 1157: During editing, Thot permits the insertion of parameters wherever the
! 1158: structure schema allows; it also permits the removal of parameters which are
! 1159: already in the document but does not allow the modification of the parameter's
! 1160: content in any way. The content is generated automatically by the editor
! 1161: during the creation of the parameter, based on the value of the parameter in
! 1162: the document.</P>
! 1163: </DIV>
! 1164:
! 1165: <DIV class="subsection">
! 1166: <H3><A name="structelem">Structured elements</A></H3>
! 1167:
! 1168: <P>
! 1169: The rules for defining structured elements are required, except in an
! 1170: extension schema: they constitute the core of a structure schema, since they
! 1171: define the structure of the different types of elements that occur in a
! 1172: document or object of the class defined by the schema.</P>
! 1173: <P>
! 1174: The first structure rule after the keyword <TT>STRUCT</TT> must define the
! 1175: structure of the class whose name appears in the first instruction
! 1176: (<TT>STRUCTURE</TT>) of the schema. This is the root rule of the schema,
! 1177: defining the root of the document tree or object tree.</P>
! 1178: <P>
! 1179: The remaining rules may be placed in any order, since the language permits the
! 1180: definition of element types before or after their use, or even in the same
! 1181: instruction in which they are used. This last case allows the definition of
! 1182: recursive structures.</P>
! 1183: <P>
! 1184: Each rule is composed of a name (the name of the element type whose structure
! 1185: is being defined) followed by an equals sign and a structure definition.</P>
! 1186: <P>
! 1187: If any local attributes are associated with the element type defined by the
! 1188: rule, they appear between parentheses after the type name. The parentheses
! 1189: contain, first, the keyword <TT>ATTR</TT>, then the list of local attributes,
! 1190: separated by commas. Each local attribute is composed of the name of the
! 1191: attribute followed by an equals sign and the definition of the attribute's
! 1192: type, just as in the definition of <A href="#globalattr">global
! 1193: attributes</A>. The name of the attribute can be preceded by an exclamation
! 1194: point to indicate that the attribute must always be present for this element
! 1195: type. The same attribute, identified by its name, can be defined as a local
! 1196: attribute for multiple element types. In this case, the equals sign and
! 1197: definition of the attribute type need only appear in the first occurrence of
! 1198: the attribute. It should be noted that global attributes cannot also be
! 1199: defined as local attributes.</P>
! 1200: <P>
! 1201: If any <A href="#restrictionextensions">extensions</A> are defined for this
! 1202: element type, a plus sign follows the structure definition and the names of
! 1203: the extension element types appear between parentheses after the plus. If
! 1204: there are multiple extensions, they are separated by commas. These types can
! 1205: either be defined in the same schema, defined in other schemas, or they may be
! 1206: base types identified by the keywords <TT>TEXT</TT>, <TT>GRAPHICS</TT>,
! 1207: <TT>SYMBOL</TT>, or <TT>PICTURE</TT>.</P>
! 1208: <P>
! 1209: <A href="#restrictionextensions">Restrictions</A> are indicated in the same
! 1210: manner as extensions, but they are introduced by a minus sign and they come
! 1211: after the extensions, or if there are no extensions, after the structure
! 1212: definition.</P>
! 1213: <P>
! 1214: If the values of attributes must be attached systematically to this element
! 1215: type, they are introduced by the keyword <TT>WITH</TT> and declared in the
! 1216: form of a list of fixed-value attributes. When such definitions of fixed
! 1217: attribute values appear, they are always the last part of the rule.</P>
! 1218: <P>
! 1219: The rule is terminated by a semicolon.</P>
! 1220: <PRE>
! 1221: RuleSeq = Rule < Rule > .
! 1222: Rule = ElemID [ LocAttrSeq ] '=' DefWithAttr ';'.
! 1223: LocAttrSeq = '(' 'ATTR' LocAttr < ';' LocAttr > ')' .
! 1224: LocAttr = [ '!' ] AttrID [ '=' AttrType ] .
! 1225: DefWithAttr = Definition
! 1226: [ '+' '(' ExtensionSeq ')' ]
! 1227: [ '-' '(' RestrictSeq ')' ]
! 1228: [ 'WITH' FixedAttrSeq ] .
! 1229: ExtensionSeq = ExtensionElem < ',' ExtensionElem > .
! 1230: ExtensionElem = ElemID / 'TEXT' / 'GRAPHICS' /
! 1231: 'SYMBOL' / 'PICTURE' .
! 1232: RestrictSeq = RestrictElem < ',' RestrictElem > .
! 1233: RestrictElem = ElemID / 'TEXT' / 'GRAPHICS' /
! 1234: 'SYMBOL' / 'PICTURE' .
! 1235: </PRE>
! 1236: <P>
! 1237: The list of fixed-value attributes is composed of a sequence of
! 1238: attribute-value pairs separated by commas. Each pair contains the name of the
! 1239: attribute and the fixed value for this element type, the two being separated
! 1240: by an equals sign. If the sign is preceded by a question mark the given value
! 1241: is only an initial value that may be modified later rather than a value fixed
! 1242: for all time. Reference attributes are an exception to this norm. They
! 1243: cannot be assigned a fixed value, but when the name of such an attribute
! 1244: appears this indicates that this element type must have a valid value for the
! 1245: attribute. For the other attribute types, the fixed value is indicated by an
! 1246: signed integer (numeric attributes), a character string between apostrophes
! 1247: (textual attributes) or the name of a value (enumeration attributes).</P>
! 1248: <P>
! 1249: Fixed-value attributes can either be <A href="#globalattr">global</A> or local
! 1250: to the element type for which they are fixed, but they must be declared before
! 1251: they are used.</P>
! 1252: <PRE>
! 1253: FixedAttrSeq = FixedAttr < ',' FixedAttr > .
! 1254: FixedAttr = AttrID [ FixedOrModifVal ] .
! 1255: FixedOrModifVal = [ '?' ] '=' FixedValue .
! 1256: FixedValue = [ '-' ] NumValue / TextVal / AttrVal .
! 1257: NumValue = NUMBER .
! 1258: TextVal = STRING .
! 1259: </PRE>
! 1260: </DIV>
! 1261:
! 1262: <DIV class="subsection">
! 1263: <H3><A name="structdef">Structure definitions</A></H3>
! 1264:
! 1265: <P>
! 1266: The structure of an element type can be a simple base type or a constructed
! 1267: type.</P>
! 1268: <P>
! 1269: For constructed types, it is frequently the case that similar structures
! 1270: appear in many places in a document. For example the contents of the
! 1271: abstract, of the introduction, and of a section can have the same structure,
! 1272: that of a sequence of paragraphs. In this case, a single, common structure
! 1273: can be defined (the paragraph sequence in this example), and the schema is
! 1274: written to indicate that each element type possesses this structure, as
! 1275: follows:</P>
! 1276: <PRE>
! 1277: Abstract = Paragraph_sequence;
! 1278: Introduction = Paragraph_sequence;
! 1279: Section_contents = Paragraph_sequence;
! 1280: </PRE>
! 1281: <P>
! 1282: The equals sign means ``has the same structure as''.</P>
! 1283: <P>
! 1284: If the element type defined is a simple base type, this is indicated by one of
! 1285: the keywords <TT>TEXT</TT>, <TT>GRAPHICS</TT>, <TT>SYMBOL</TT>, or
! 1286: <TT>PICTURE</TT>. If some local attributes must be associated with a base
! 1287: type, the keyword of the base type is followed by the declaration of the local
! 1288: attributes using the syntax <A href="#structelem">presented above.</A></P>
! 1289: <P>
! 1290: In the case of an open choice, the type is indicated by the keyword
! 1291: <TT>UNIT</TT> for units or the keyword <TT>NATURE</TT> for objects having
! 1292: arbitrary structure.</P>
! 1293: <P>
! 1294: A unit represents one of the two following categories:</P>
! 1295: <UL>
! 1296: <LI>a base type: text, graphical element, symbol, image,
! 1297: <LI>an element whose type is chosen from among the types definedas units in
! 1298: the <TT>UNITS</TT>section of the document's structure schema.It can also be
! 1299: chosen from among the types defined as<A href="#schemasandunits">units</A>in
! 1300: the <A href="#units"><TT>UNITS</TT> section</A>of the structure schemas that
! 1301: defines the ancestors of theelement to which the rule is applied.
! 1302: </UL>
! 1303: <P>
! 1304: Before the creation of an element defined as a unit, the Thot editor asks the
! 1305: user to choose between the categories of elements.</P>
! 1306: <P>
! 1307: Thus, the contents of a paragraph can be specified as a sequence of units,
! 1308: which will permit the inclusion in the paragraphs of character strings,
! 1309: symbols, and various elements, such as cross-references, if these are defined
! 1310: as units.</P>
! 1311: <P>
! 1312: A schema object (keyword <TT>NATURE</TT>) represents an object defined by a
! 1313: structure schema freely chosen from among the available schemas; in the case
! 1314: the element type is defined by the first rule (the root rule) of the chosen
! 1315: schema.</P>
! 1316: <P>
! 1317: If the element type defined is a constructed type, the list, aggregate,
! 1318: choice, and reference constructors are used. In this case the definition
! 1319: begins with a keyword identifying the constructor. This keyword is followed
! 1320: by a syntax specific to each constructor.</P>
! 1321: <P>
! 1322: The local attribute definitions appear after the name of the element type
! 1323: being defined, if this element type has <A href="#structelem">local
! 1324: attributes</A>.</P>
! 1325: <PRE>
! 1326: Definition = BaseType [ LocAttrSeq ] / Constr / Element .
! 1327: BaseType = 'TEXT' / 'GRAPHICS' / 'SYMBOL' / 'PICTURE' /
! 1328: 'UNIT' / 'NATURE' .
! 1329: Element = ElemID [ ExtOrDef ] .
! 1330: ExtOrDef = 'EXTERN' / 'INCLUDED' /
! 1331: [ LocAttrSeq ] '=' Definition .
! 1332: Constr = 'LIST' [ '[' min '..' max ']' ] 'OF'
! 1333: '(' DefWithAttr ')' /
! 1334: 'BEGIN' DefOptSeq 'END' /
! 1335: 'AGGREGATE' DefOptSeq 'END' /
! 1336: 'CASE' 'OF' DefSeq 'END' /
! 1337: 'REFERENCE' '(' RefType ')' /
! 1338: 'PAIR' .
! 1339: </PRE>
! 1340:
! 1341: <DIV class="subsubsection">
! 1342: <H4>List</H4>
! 1343:
! 1344: <P>
! 1345: The list constructor permits the definition of an element type composed of a
! 1346: list of elements, all of the same type. A list definition begins with the
! 1347: <TT>LIST</TT> keyword followed by an optional range, the keyword <TT>OF</TT>,
! 1348: and the definition, between parentheses, of the element type which must
! 1349: compose the list. The optional range is composed of the minimum and maximum
! 1350: number of elements for the list separated by two periods and enclosed by
! 1351: brackets. If the range is not present, the number of list elements is
! 1352: unconstrained. When only one of the two bounds of the range is unconstrained,
! 1353: it is represented by a star ('*') character. Even when both bounds are
! 1354: unconstrained, they can be specified by <TT>[*..*]</TT>, but it is simpler not
! 1355: to specify any bound.</P>
! 1356: <PRE>
! 1357: 'LIST' [ '[' min '..' max ']' ]
! 1358: 'OF' '(' DefWithAttr ')'
! 1359: min = Integer / '*' .
! 1360: max = Integer / '*' .
! 1361: Integer = NUMBER .
! 1362: </PRE>
! 1363: <P>
! 1364: Before the document is edited, the Thot editor creates the minimum number of
! 1365: elements for the list. If no minimum was given, it creates a single element.
! 1366: If a maximum number of elements is given and that number is attained, the
! 1367: editor refuses to create new elements for the list.</P>
! 1368: <BLOCKQUOTE class="example">
! 1369: <P>
! 1370: <STRONG>Example:</STRONG></P>
! 1371: <P>
! 1372: The following two instructions define the body of a document as asequence of
! 1373: at least two chapters and the contents of a section as asequence of
! 1374: paragraphs. A single paragraph can be the entire contentsof a section.</P>
! 1375: <PRE>
! 1376: Body = LIST [2..*] OF (Chapter);
! 1377: Section_contents = LIST OF (Paragraph);
! 1378: </PRE>
! 1379: </BLOCKQUOTE>
! 1380: </DIV>
! 1381:
! 1382: <DIV class="subsubsection">
! 1383: <H4>Aggregate</H4>
! 1384:
! 1385: <P>
! 1386: The aggregate constructor is used to define an element type as a collection of
! 1387: sub-elements, each having a fixed type. The collection may be ordered or
! 1388: unordered. The elements composing the collection are called
! 1389: <EM>components</EM>. In the definition of an aggregate, a keyword indicates
! 1390: whether or not the aggregate is ordered: <TT>BEGIN</TT> for an ordered
! 1391: aggregate, <TT>AGGREGATE</TT> for an unordered aggregate. This keyword is
! 1392: followed by the list of component type definitions which is terminated by the
! 1393: <TT>END</TT> keyword. The component type definitions are separated by
! 1394: commas.</P>
! 1395: <P>
! 1396: Before creating an aggregate, the Thot editor creates all the aggregate's
! 1397: components in the order they appear in the structure schema, even for
! 1398: unordered aggregates. However, unlike ordered aggregates, the components of
! 1399: an unordered aggregate may be rearranged using operations of the Thot editor.
! 1400: The exceptions to the rule are any components whose name was preceded by a
! 1401: question mark character ('?'). These components, which are optional, can be
! 1402: created by explicit request, possibly at the time the aggregate is created,
! 1403: but they are not created automatically <EM>prior</EM> to the creation of the
! 1404: aggregate.</P>
! 1405: <PRE>
! 1406: 'BEGIN' DefOptSeq 'END'
! 1407: DefOptSeq = DefOpt ';' < DefOpt ';' > .
! 1408: DefOpt = [ '?' ] DefWithAttr .
! 1409: </PRE>
! 1410: <BLOCKQUOTE class="example">
! 1411: <P>
! 1412: <STRONG>Example:</STRONG></P>
! 1413: <P>
! 1414: In a bilingual document, each paragraph has an English version andFrench
! 1415: version. In certain cases, the translator wants to add amarginal note, but
! 1416: this note is present in very few paragraphs. Thus,it must not be created
! 1417: systematically for every paragraph. Abilingual paragraph of this type is
! 1418: declared:</P>
! 1419: <PRE>
! 1420: Bilingual_paragraph = BEGIN
! 1421: French_paragraph = TEXT;
! 1422: English_paragraph = TEXT;
! 1423: ? Note = TEXT;
! 1424: END;
! 1425: </PRE>
! 1426: </BLOCKQUOTE>
! 1427: </DIV>
! 1428:
! 1429: <DIV class="subsubsection">
! 1430: <H4>Choice</H4>
! 1431:
! 1432: <P>
! 1433: The choice constructor permits the definition of an element type which is
! 1434: chosen from among a set of possible types. The keywords <TT>CASE</TT> and
! 1435: <TT>OF</TT> are followed by a list of definitions of possible types, which are
! 1436: separated by semicolons and terminated by the <TT>END</TT> keyword.</P>
! 1437: <PRE>
! 1438: 'CASE' 'OF' DefSeq 'END'
! 1439: DefSeq = DefWithAttr ';' < DefWithAttr ';' > .
! 1440: </PRE>
! 1441: <P>
! 1442: Before the creation of an element defined as a choice, the Thot editor
! 1443: presents the list of possible types for the element to the user. The user has
! 1444: only to select the element type that he wants to create from this list.</P>
! 1445: <P>
! 1446: The order of the type declarations is important. It determines the order of
! 1447: the list presented to the user before the creation of the element. Also, when
! 1448: a Choice element is being created automatically, the first type in the list is
! 1449: used. In fact, using the Thot editor, when an empty Choice element is
! 1450: selected, it is possible to select this element and to enter its text from
! 1451: keyboard. In this case, the editor uses the first element type which can
! 1452: contain an atom of the character string type.</P>
! 1453: <P>
! 1454: The two special cases of the choice constructor, the <A
! 1455: href="#structdef"><EM>schema</EM></A> and the <A
! 1456: href="#units"><EM>unit</EM></A> are discussed elsewhere.</P>
! 1457: <BLOCKQUOTE class="example">
! 1458: <P>
! 1459: <STRONG>Example:</STRONG></P>
! 1460: <P>
! 1461: It is common in documents to treat a variety of objects as if theywere
! 1462: ordinary paragraphs. Thus, a ``Paragraph'' might actually becomposed of a
! 1463: block of text (an ordinary paragraph), or a mathematicalformula whose
! 1464: structure is defined by another structure schema namedMath, or a table, also
! 1465: defined by another structure schema. Here is adefinition of such a
! 1466: paragraph:</P>
! 1467: <PRE>
! 1468: Paragraph = CASE OF
! 1469: Simple_text = TEXT;
! 1470: Formula = Math;
! 1471: Table_para = Table;
! 1472: END;
! 1473: </PRE>
! 1474: </BLOCKQUOTE>
! 1475: </DIV>
! 1476:
! 1477: <DIV class="subsubsection">
! 1478: <H4><A name="references">Reference</A></H4>
! 1479:
! 1480: <P>
! 1481: Like all elements in Thot, references are typed. An element type defined as a
! 1482: reference is a cross-reference to an element of some other given type. The
! 1483: keyword <TT>REFERENCE</TT> is followed by the name of a type enclosed in
! 1484: parentheses. When the type which is being cross-referenced is defined in
! 1485: another structure schema, the type name is itself followed by the name of the
! 1486: external structure schema in which it is defined.</P>
! 1487: <P>
! 1488: When the designated element type is a <A href="#pairs">mark pair</A>, it can
! 1489: be preceded by a <TT>FIRST</TT> or <TT>SECOND</TT> keyword. These keywords
! 1490: indicate whether the reference points to the first or second mark of the pair.
! 1491: If the reference points to a pair and neither of these two keywords is
! 1492: present, the reference is considered to point to the first mark of the
! 1493: pair.</P>
! 1494: <P>
! 1495: There is an exception to the principle of typed references: it is possible to
! 1496: define a reference which designates an element of any type, which can either
! 1497: be in the same document or another document. In this case, it suffices to put
! 1498: the keyword <TT>ANY</TT> in the parentheses which indicate the referenced
! 1499: element type.</P>
! 1500: <PRE>
! 1501: 'REFERENCE' '(' RefType ')'
! 1502: RefType = 'ANY' / [ FirstSec ] ElemID [ ExtStruct ] .
! 1503: </PRE>
! 1504: <P>
! 1505: When defining an inclusion, the <TT>REFERENCE</TT> keyword is not used.
! 1506: Inclusions with complete expansion are not declared as such in the structure
! 1507: schemas, since any element defined in a structure schema can be replaced by an
! 1508: element of the same type. Instead, inclusions without expansion or with
! 1509: partial expansion must be declared explicitly whenever they will include a
! 1510: complete object ( and not a part of an object). In this case, the object type
! 1511: to be included (that is, the name of its structure schema) is followed by a
! 1512: keyword: <TT>EXTERN</TT> for inclusion without expansion and <TT>INCLUDED</TT>
! 1513: for partial expansion.</P>
! 1514: <P>
! 1515: Before creating a cross-reference or an inclusion, the Thot editor asks the
! 1516: user to choose, from the document images displayed, the referenced or included
! 1517: element.</P>
! 1518: <BLOCKQUOTE class="example">
! 1519: <P>
! 1520: <STRONG>Example:</STRONG></P>
! 1521: <P>
! 1522: If the types Note and Section are defined in theArticle structure schema, it
! 1523: is possible to define, in the samestructure schema, a reference to a note and
! 1524: a reference to a sectionin this manner:</P>
! 1525: <PRE>
! 1526: Ref_note = REFERENCE (Note);
! 1527: Ref_section = REFERENCE (Section);
! 1528: </PRE>
! 1529: <P>
! 1530: It is also possible to define the generic structure of a collection of
! 1531: articles, which include (with partial expansion) objects of the Article class
! 1532: and which possess an introduction which may include cross-references to
! 1533: sections of the included articles. In the Collection structure schema, the
! 1534: definitions are:</P>
! 1535: <PRE>
! 1536: Collection = BEGIN
! 1537: Collection_title = TEXT;
! 1538: Introduction = LIST OF (Elem = CASE OF
! 1539: TEXT;
! 1540: Ref_sect;
! 1541: END);
! 1542: Body = LIST OF (Article INCLUDED);
! 1543: END;
! 1544: Ref_sect = REFERENCE (Section (Article));
! 1545: </PRE>
! 1546: <P>
! 1547: Here we define a Folder document class which has a title and includes
! 1548: documents of different types, particularly Folders:</P>
! 1549: <PRE>
! 1550: Folder = BEGIN
! 1551: Folder_title = TEXT;
! 1552: Folder_contents = LIST OF (Document);
! 1553: END;
! 1554:
! 1555: Document = CASE OF
! 1556: Article EXTERN;
! 1557: Collection EXTERN;
! 1558: Folder EXTERN;
! 1559: END;
! 1560: </PRE>
! 1561: <P>
! 1562: Under this definition, Folder represents either an aggregate which contains a
! 1563: folder title and the list of included documents or an included folder. To
! 1564: resolve this ambiguity, in the P language, the placement of a star character
! 1565: in front of the type name (here, Folder) indicates an included document.</P>
! 1566: </BLOCKQUOTE>
! 1567: </DIV>
! 1568:
! 1569: <DIV class="subsubsection">
! 1570: <H4><A name="pairs">Mark pairs</A></H4>
! 1571:
! 1572: <P>
! 1573: Like other elements, mark pairs are typed. The two marks of the pair have the
! 1574: same type, but there exist two predefined subtypes which apply to all mark
! 1575: pairs: the first mark of the pair (called <TT>First</TT> in the P and T
! 1576: languages) and the second mark (called <TT>Second</TT>).</P>
! 1577: <P>
! 1578: In the S language, a mark pair is noted simply by the <TT>PAIR</TT>
! 1579: keyword.</P>
! 1580: <P>
! 1581: In the Thot editor, marks are always moved or destroyed together. The two
! 1582: marks of a pair have the same identifier, unique within the document, which
! 1583: permits intertwining mark pairs without risk of ambiguity.</P>
! 1584: </DIV>
! 1585: </DIV>
! 1586:
! 1587: <DIV class="subsection">
! 1588: <H3>Imports</H3>
! 1589:
! 1590: <P>
! 1591: Because of schema constructors, it is possible, before editing a document, to
! 1592: use classes defined by other structure schemas whenever they are needed. It is
! 1593: also possible to assign specific document classes to certain element types. In
! 1594: this case, these classes are simply designated by their name. In fact, if a
! 1595: type name is not defined in the structure schema, it is assumed that it
! 1596: specifies a structure defined by another structure schema.</P>
! 1597: <BLOCKQUOTE class="example">
! 1598: <P>
! 1599: <STRONG>Example:</STRONG></P>
! 1600: <P>
! 1601: If the types Math and Table don't appear in the left partof a structure rule
! 1602: in the schema, the following two rules indicatethat a formula has the
! 1603: structure of an object defined by the structureschema Math and that a table
! 1604: element has the structure of anobject defined by the Table schema.</P>
! 1605: <PRE>
! 1606: Formula = Math;
! 1607: Table_elem = Table;
! 1608: </PRE>
! 1609: </BLOCKQUOTE>
! 1610: </DIV>
! 1611:
! 1612: <DIV class="subsection">
! 1613: <H3>Extension rules</H3>
! 1614:
! 1615: <P>
! 1616: The <TT>EXTENS</TT> section, which can only appear in an extension schema,
! 1617: defines complements to the rules in the primary schema (i.e. the structure
! 1618: schema to which the extension schema will be applied). More precisely, this
! 1619: section permits the addition to an existing type of local attributes,
! 1620: extensions, restrictions and fixed-value attributes.</P>
! 1621: <P>
! 1622: These additions can be applied to the root rule of the primary schema,
! 1623: designated by the keyword <TT>Root</TT>, or to any other explicitly named
! 1624: rule.</P>
! 1625: <P>
! 1626: Extension rules are separated from each other by a semicolon and each
! 1627: extension rule has the same syntax as a <A href="#structelem">structure
! 1628: rule</A>, but the part which defines the constructor is absent.</P>
! 1629: <PRE>
! 1630: ExtenRuleSeq = ExtensRule ';' < ExtensRule ';' > .
! 1631: ExtensRule = RootOrElem [ LocAttrSeq ]
! 1632: [ '+' '(' ExtensionSeq ')' ]
! 1633: [ '-' '(' RestrictSeq ')' ]
! 1634: [ 'WITH' FixedAttrSeq ] .
! 1635: RootOrElem = 'Root' / ElemID .
! 1636: </PRE>
! 1637: </DIV>
! 1638:
! 1639: <DIV class="subsection">
! 1640: <H3>Associated elements</H3>
! 1641:
! 1642: <P>
! 1643: If associated elements are necessary, they must be declared in a specific
! 1644: section of the structure schema, introduced by the keyword <TT>ASSOC</TT>.
! 1645: Each associated element type is specified like any other structured element.
! 1646: However, these types must not appear in any other element types of the schema,
! 1647: except in <TT>REFERENCE</TT> rules.</P>
! 1648: </DIV>
! 1649:
! 1650: <DIV class="subsection">
! 1651: <H3><A name="units">Units</A></H3>
! 1652:
! 1653: <P>
! 1654: The <TT>UNITS</TT> section of the structure schema contains the declarations
! 1655: of the element types which can be used in the external objects making up parts
! 1656: of the document or in objects of the class defined by the schema. As with
! 1657: associated elements, these element types are defined just like other
! 1658: structured element types. They can be used in the other element types of the
! 1659: schema, but they can also be used in any other rule of the schema.</P>
! 1660: <BLOCKQUOTE class="example">
! 1661: <P>
! 1662: <STRONG>Example:</STRONG></P>
! 1663: <P>
! 1664: If references to notes are declared as units:</P>
! 1665: <PRE>
! 1666: UNITS
! 1667: Ref_note = REFERENCE (Note);
! 1668: </PRE>
! 1669: <P>
! 1670: then it is possible to use references to notes in a cell of a table,even when
! 1671: <TT>Table</TT>is an external structure schema. The<TT>Table<TT> schema must
! 1672: declare a cell to be a sequence of units, which can then be base element types
! 1673: (text, for example) or references to notes in the document. <PRE>
! 1674: Cell = LIST OF (UNITS);
! 1675: </PRE>
! 1676: </TT></TT></P>
! 1677: </BLOCKQUOTE>
! 1678: </DIV>
! 1679:
! 1680: <DIV class="subsection">
! 1681: <H3><A name="skeleton">Skeleton elements</A></H3>
! 1682:
! 1683: <P>
! 1684: When editing a document which contains or must contain external references to
! 1685: several other documents, it may be necessary to load a large number of
! 1686: documents, simply to see the parts designated by the external references of
! 1687: the document while editing, or to access the source of included elements. In
! 1688: this case, the external documents are not modified and it is only necessary to
! 1689: see the elements of these documents which could be referenced. Because of
! 1690: this, the editor will suggest that the documents be loaded in ``skeleton''
! 1691: form. This form contains only the elements of the document explicitly
! 1692: mentioned in the <TT>EXPORT</TT> section of their structure schema and, for
! 1693: these elements, only the part of the contents specified in that section. This
! 1694: form has the advantage of being very compact, thus requiring very few
! 1695: resources from the editor. This is also the skeleton form which constitutes
! 1696: the expanded form of <A href="#inclusion">inclusions</A> with partial
! 1697: expansion.</P>
! 1698: <P>
! 1699: Skeleton elements must be declared explicitly in the <TT>EXPORT</TT> section
! 1700: of the structure schema that defines them. This section begins with the
! 1701: keyword <TT>EXPORT</TT> followed by a comma-separated list of the element
! 1702: types which must appear in the skeleton form and ending with a semicolon.
! 1703: These types must have been previously declared in the schema.</P>
! 1704: <P>
! 1705: For each skeleton element type, the part of the contents which is loaded by
! 1706: the editor, and therefore displayable, can be specified by putting the keyword
! 1707: <TT>WITH</TT> and the name of the contained element type to be loaded after
! 1708: the name of the skeleton element type. In this case only that named element,
! 1709: among all the elements contained in the exportable element type, will be
! 1710: loaded. If the <TT>WITH</TT> is absent, the entire contents of the skeleton
! 1711: element will be loaded by the editor. If instead, it is better that the
! 1712: skeleton form not load the contents of a particular element type, the keyword
! 1713: <TT>WITH</TT> must be followed by the word <TT>Nothing</TT>.</P>
! 1714: <PRE>
! 1715: [ 'EXPORT' SkeletonSeq ]
! 1716:
! 1717: SkeletonSeq = SkelElem < ',' SkelElem > ';' .
! 1718: SkelElem = ElemID [ 'WITH' Contents ] .
! 1719: Contents = 'Nothing' / ElemID [ ExtStruct ] .
! 1720: </PRE>
! 1721: <BLOCKQUOTE class="example">
! 1722: <P>
! 1723: <STRONG>Example:</STRONG></P>
! 1724: <P>
! 1725: Suppose that, in documents of the article class, the element
! 1726: typesArticle_title, Figure, Section, Paragraph, and Biblio should appearin the
! 1727: skeleton form in order to make it easier to create externalreferences to them
! 1728: from other documents. When loading an article inits skeleton form, all of
! 1729: these element types will be loaded exceptfor paragraphs, but only the article
! 1730: title will be loaded in itsentirety. For figures, the legend will be loaded,
! 1731: while for sections,the title will be loaded, and for bibliographic entries,
! 1732: only thetitle that they contain will be loaded. Note that
! 1733: bibliographicelements are defined in another structure schema, RefBib. To
! 1734: producethis result, the following declarations should be placed in the
! 1735: Articlestructure schema:</P>
! 1736: <PRE>
! 1737: EXPORT
! 1738: Article_title,
! 1739: Figure With Legend,
! 1740: Section With Section_title,
! 1741: Paragraph With Nothing,
! 1742: Biblio With Biblio_title(RefBib);
! 1743: </PRE>
! 1744: </BLOCKQUOTE>
! 1745: </DIV>
! 1746:
! 1747: <DIV class="subsection">
! 1748: <H3>Exceptions</H3>
! 1749:
! 1750: <P>
! 1751: The behavior of the Thot editor and the actions that it performs are
! 1752: determined by the structure schemas. These actions are applied to all
! 1753: document and object types in accordance with their generic structure. For
! 1754: certain object types, such as tables and graphics, these actions are not
! 1755: sufficient or are poorly adapted and some special actions must be added to or
! 1756: substituted for certain standard actions. These special actions are called
! 1757: <EM>exceptions</EM>.</P>
! 1758: <P>
! 1759: Exceptions only inhibit or modify certain standard actions, but they can be
! 1760: used freely in every structure schema.</P>
! 1761: <P>
! 1762: Each structure schema can contain a section defining exceptions. It begins
! 1763: with the keyword <TT>EXCEPT</TT> and is composed of a sequence of exception
! 1764: declarations, separated by semicolons. Each declaration of an exception
! 1765: begins with the name of an element type or attribute followed by a colon. This
! 1766: indicates the element type or attribute to which the following exceptions
! 1767: apply. When the given element type name is a <A href="#pairs">mark pair</A>,
! 1768: and only in this case, the type name can be preceded by the keyword
! 1769: <TT>First</TT> or <TT>Second</TT>, to indicate if the exceptions which follow
! 1770: are associated with the first mark of the pair or the second. In the absence
! 1771: of this keyword, the first mark is used.</P>
! 1772: <P>
! 1773: When placed in an <A href="#extsch">extension schema</A>, the keyword
! 1774: <TT>EXTERN</TT> indicates that the type name which follows is found in the
! 1775: principal schema (the schema being extended by the extension schema). The
! 1776: exceptions are indicated by a name. They are separated by semicolons.</P>
! 1777: <PRE>
! 1778: [ 'EXCEPT' ExceptSeq ]
! 1779:
! 1780: ExceptSeq = Except ';' < Except ';' > .
! 1781: Except = [ 'EXTERN' ] [ FirstSec ] ExcTypeOrAttr
! 1782: ':' ExcValSeq .
! 1783: ExcTypeOrAttr = ElemID / AttrID .
! 1784: ExcValSeq = ExcValue < ',' ExcValue > .
! 1785: ExcValue ='NoCut' / 'NoCreate' /
! 1786: 'NoHMove' / 'NoVMove' / 'NoMove' /
! 1787: 'NoHResize' / 'NoVResize' / 'NoResize' /
! 1788: 'NewWidth' / 'NewHeight' /
! 1789: 'NewHPos' / 'NewVPos' /
! 1790: 'Invisible' / 'NoSelect' /
! 1791: 'Hidden' / 'ActiveRef' /
! 1792: 'ImportLine' / 'ImportParagraph' /
! 1793: 'NoPaginate' / 'ParagraphBreak' /
! 1794: 'HighlightChildren' / 'ExtendedSelection' .
! 1795: </PRE>
! 1796: <P>
! 1797: The following are the available exceptions:</P>
! 1798: <DL>
! 1799: <DT><TT>NoCut</TT></DT>
! 1800: <DD>This exception can only be applied to elementtypes. Elements of a type to
! 1801: which this exception is applied cannotbe destroyed by the editor.
! 1802: </DD>
! 1803: <DT><TT>NoCreate</TT></DT>
! 1804: <DD>This exception can only be applied to elementtypes. Elements of a type to
! 1805: which this exception is applied cannotbe created by ordinary commands for
! 1806: creating new elements. Theseelements are usually created by special actions
! 1807: associated with otherexceptions.
! 1808: </DD>
! 1809: <DT><TT>NoHMove</TT></DT>
! 1810: <DD>This exception can only be applied to elementtypes. Elements of a type to
! 1811: which this exception is applied cannotbe moved horizontally with the mouse.
! 1812: </DD>
! 1813: <DT><TT>NoVMove</TT></DT>
! 1814: <DD>This exception can only be applied to elementtypes. Elements of a type to
! 1815: which this exception is applied cannotbe moved vertically with the mouse.
! 1816: </DD>
! 1817: <DT><TT>NoMove</TT></DT>
! 1818: <DD>This exception can only be applied to elementtypes. Elements of a type to
! 1819: which this exception is applied cannotbe moved in any direction with the
! 1820: mouse.
! 1821: </DD>
! 1822: <DT><TT>NoHResize</TT></DT>
! 1823: <DD>This exception can only be applied to elementtypes. Elements of a type to
! 1824: which this exception is applied cannotbe resized horizontally with the mouse.
! 1825: </DD>
! 1826: <DT><TT>NoVResize</TT></DT>
! 1827: <DD>This exception can only be applied to elementtypes. Elements of a type to
! 1828: which this exception is applied cannotbe resized vertically with the mouse.
! 1829: </DD>
! 1830: <DT><TT>NoResize</TT></DT>
! 1831: <DD>This exception can only be applied to elementtypes. Elements of a type to
! 1832: which this exception is applied cannotbe resized in any direction with the
! 1833: mouse.
! 1834: </DD>
! 1835: <DT><TT>NoSelect</TT></DT>
! 1836: <DD>This exception can only be applied to elementtypes. Elements of a type to
! 1837: which this exception is applied cannotbe selected directly with the mouse, but
! 1838: they can be selected by othermethods provided by the editor.
! 1839: </DD>
! 1840: <DT><TT>NewWidth</TT></DT>
! 1841: <DD>This exception can only be applied to numericattributes. If the width of
! 1842: an element which has this attribute ismodified with the mouse, the value of
! 1843: the new width will be assignedto the attribute.
! 1844: </DD>
! 1845: <DT><TT>NewHeight</TT></DT>
! 1846: <DD>This exception can only be applied to numericattributes. If the height of
! 1847: an element which has this attribute ismodified with the mouse, the value of
! 1848: the new height will be assignedto the attribute.
! 1849: </DD>
! 1850: <DT><TT>NewHPos</TT></DT>
! 1851: <DD>This exception can only be applied to numericattributes. If the
! 1852: horizontal position of an element which has thisattribute is modified with the
! 1853: mouse, the value of the new horizontalposition will be assigned to the
! 1854: attribute.
! 1855: </DD>
! 1856: <DT><TT>NewVPos</TT></DT>
! 1857: <DD>This exception can only be applied to numericattributes. If the vertical
! 1858: position of an element which has thisattribute is modified with the mouse, the
! 1859: value of the new verticalposition will be assigned to the attribute.
! 1860: </DD>
! 1861: <DT><TT>Invisible</TT></DT>
! 1862: <DD>This exception can only be applied toattributes, but can be applied to all
! 1863: attribute types. It indicatesthat the attribute must not be seen by the user
! 1864: and that its valuemust not be changed directly. This exception is usually
! 1865: used whenanother exception manipulates the value of an attribute.
! 1866: </DD>
! 1867: <DT><TT>Hidden</TT></DT>
! 1868: <DD>This exception can only be applied to elementtypes. It indicates that
! 1869: elements of this type, although present inthe document's structure, must not
! 1870: be shown to the user of the editor.In particular, the creation menus must not
! 1871: propose this type and theselection message must not pick it.
! 1872: </DD>
! 1873: <DT><TT>ActiveRef</TT></DT>
! 1874: <DD>This exception can only be applied toattributes of the reference type. It
! 1875: indicates that when the user ofthe editor makes a double click on an element
! 1876: which possesses areference attribute having this exception, the element
! 1877: designated bythe reference attribute will be selected.
! 1878: </DD>
! 1879: <DT><TT>ImportLine</TT></DT>
! 1880: <DD>This exception can only be applied to elementtypes. It indicates that
! 1881: elements of this type should receive thecontent of imported text files. An
! 1882: element is created for each lineof the imported file. A structure schema
! 1883: cannot contain severalexceptions <TT>ImportLine</TT>and, if it contains one,
! 1884: it should notcontain any exception <TT>ImportParagraph</TT>.
! 1885: </DD>
! 1886: <DT><TT>ImportParagraph</TT></DT>
! 1887: <DD>This exception can only be applied to elementtypes. It indicates that
! 1888: elements of this type should receive thecontent of imported text files. An
! 1889: element is created for each paragraphof the imported file. A paragraph is a
! 1890: sequence of lines without anyempty line. A structure schema cannot contain
! 1891: several exceptions<TT>ImportParagraph</TT>and, if it contains one, it should
! 1892: not contain anyexception <TT>ImportLine</TT>.
! 1893: </DD>
! 1894: <DT><TT>NoPaginate</TT></DT>
! 1895: <DD>This exception can only be applied to the rootelement, i.e. the name that
! 1896: appear after the keyword <TT>STRUCTURE</TT>at thebeginning of the structure
! 1897: schema. It indicates that the editor should notallow the user to paginate
! 1898: documents of that type.
! 1899: </DD>
! 1900: <DT><TT>ParagraphBreak</TT></DT>
! 1901: <DD>This exception can only be applied to elementtypes. When the caret is
! 1902: within an element of a type to which this exceptionis applied, it is that
! 1903: element that will be split when the user hits theReturn key.
! 1904: </DD>
! 1905: <DT><TT>HighlightChildren</TT></DT>
! 1906: <DD>This exception can only be applied to elementtypes. Elements of a type to
! 1907: which this exception is applied are nothighlighted themselves when they are
! 1908: selected, but all their children arehighlighted instead.
! 1909: </DD>
! 1910: <DT><TT>ExtendedSelection</TT></DT>
! 1911: <DD>This exception can only be applied to elementtypes. The selection
! 1912: extension command (middle button of the mouse) only addthe clicked element (if
! 1913: it has that exception) to the current selection,without selecting other
! 1914: elements between the current selection and theclicked element.
! 1915: </DD>
! 1916: </DL>
! 1917: <BLOCKQUOTE class="example">
! 1918: <P>
! 1919: <STRONG>Example:</STRONG></P>
! 1920: <P>
! 1921: Consider a structure schema for object-style graphics which definesthe
! 1922: Graphic_object element type with the associated Height and Weight
! 1923: numericattributes. Suppose that we want documents of this class to have
! 1924: thefollowing qualities:</P>
! 1925: <UL>
! 1926: <LI>Whenever the width or height of an object is changed using themouse, the
! 1927: new values are stored in the object's Width andHeight attributes.
! 1928: <LI>The user should not be able to change the values of theWidth and Height
! 1929: attributes via the Attributes menu ofthe Thot editor.
! 1930: </UL>
! 1931: <P>
! 1932: The following exceptions will produce this effect.</P>
! 1933: <PRE>
! 1934: STRUCT
! 1935: ...
! 1936: Objet_graphique (ATTR Height = Integer; Width = Integer)
! 1937: = GRAPHICS with Height ?= 10, Width ?= 10;
! 1938: ...
! 1939: EXCEPT
! 1940: Height: NewHeight, Invisible;
! 1941: Width: NewWidth, Invisible;
! 1942: </PRE>
! 1943: </BLOCKQUOTE>
! 1944: </DIV>
! 1945: </DIV>
! 1946:
! 1947: <DIV class="section">
! 1948: <H2>Some examples</H2>
! 1949:
! 1950: <P>
! 1951: In order to illustrate the principles of the document model and the syntax of
! 1952: the S language, this section presents two examples of structure schemas. One
! 1953: defines a class of documents, the other defines a class of objects.</P>
! 1954:
! 1955: <DIV class="subsection">
! 1956: <H3>A class of documents: articles</H3>
! 1957:
! 1958: <P>
! 1959: This example shows a possible structure for articles published in a journal.
! 1960: Text between braces is comments.</P>
! 1961: <PRE>
! 1962: STRUCTURE Article; { This schema defines the Article class }
! 1963: DEFPRES ArticleP; { The default presentation schema is
! 1964: ArticleP }
! 1965: ATTR { Global attribute definitions }
! 1966: WordType = Definition, IndexWord, DocumentTitle;
! 1967: { A single global attribute is defined, with three values }
! 1968: STRUCT { Definition of the generic structure }
! 1969: Article = BEGIN { The Article class has an aggregate
! 1970: structure }
! 1971: Title = BEGIN { The title is an aggregate }
! 1972: French_title =
! 1973: Text WITH Language='Fran\347ais';
! 1974: English_title =
! 1975: Text WITH Language='English';
! 1976: END;
! 1977: Authors =
! 1978: LIST OF (Author
! 1979: (ATTR Author_type=principal,secondary)
! 1980: { The Author type has a local attribute }
! 1981: = BEGIN
! 1982: Author_name = Text;
! 1983: Info = Paragraphs ;
! 1984: { Paragraphs is defined later }
! 1985: Address = Text;
! 1986: END
! 1987: );
! 1988: Keywords = Text;
! 1989: { The journal's editor introduces the article
! 1990: with a short introduction, in French and
! 1991: in English }
! 1992: Introduction =
! 1993: BEGIN
! 1994: French_intr = Paragraphs WITH
! 1995: Language='Fran\347ais';
! 1996: English_intr = Paragraphs WITH
! 1997: Language='English';
! 1998: END;
! 1999: Body = Sections; { Sections are defined later }
! 2000: { Appendixes are only created on demand }
! 2001: ? Appendices =
! 2002: LIST OF (Appendix =
! 2003: BEGIN
! 2004: Appendix_Title = Text;
! 2005: Appendix_Contents = Paragraphs;
! 2006: END
! 2007: );
! 2008: END; { End of the Article aggregate }
! 2009:
! 2010: Sections = LIST [2..*] OF (
! 2011: Section = { At least 2 sections }
! 2012: BEGIN
! 2013: Section_title = Text;
! 2014: Section_contents =
! 2015: BEGIN
! 2016: Paragraphs;
! 2017: Sections; { Sections at a lower level }
! 2018: END;
! 2019: END
! 2020: );
! 2021:
! 2022: Paragraphs = LIST OF (Paragraph = CASE OF
! 2023: Enumeration =
! 2024: LIST [2..*] OF
! 2025: (Item = Paragraphs);
! 2026: Isolated_formula = Formula;
! 2027: LIST OF (UNIT);
! 2028: END
! 2029: );
! 2030:
! 2031: ASSOC { Associated elements definitions }
! 2032:
! 2033: Figure = BEGIN
! 2034: Figure_legend = Text;
! 2035: Illustration = NATURE;
! 2036: END;
! 2037:
! 2038: Biblio_citation = CASE OF
! 2039: Ref_Article =
! 2040: BEGIN
! 2041: Authors_Bib = Text;
! 2042: Article_Title = Text;
! 2043: Journal = Text;
! 2044: Page_Numbers = Text;
! 2045: Date = Text;
! 2046: END;
! 2047: Ref_Livre =
! 2048: BEGIN
! 2049: Authors_Bib; { Defined above }
! 2050: Book_Title = Text;
! 2051: Editor = Text;
! 2052: Date; { Defined above }
! 2053: END;
! 2054: END;
! 2055:
! 2056: Note = Paragraphs - (Ref_note);
! 2057:
! 2058: UNITS { Elements which can be used in objects }
! 2059:
! 2060: Ref_note = REFERENCE (Note);
! 2061: Ref_biblio = REFERENCE (Biblio_citation);
! 2062: Ref_figure = REFERENCE (Figure);
! 2063: Ref_formula = REFERENCE (Isolated_formula);
! 2064:
! 2065: EXPORT { Skeleton elements }
! 2066:
! 2067: Title,
! 2068: Figure with Figure_legend,
! 2069: Section With Section_title;
! 2070:
! 2071: END { End of the structure schema }
! 2072: </PRE>
! 2073: <P>
! 2074: This schema is very complete since it defines both paragraphs and
! 2075: bibliographic citations. These element types could just as well be defined in
! 2076: other structure schemas, as is the case with the <TT>Formula</TT> class. All
! 2077: sorts of other elements can be inserted into an article, since a paragraph can
! 2078: contain any type of unit. Similarly, figures can be any class of document or
! 2079: object that the user chooses.</P>
! 2080: <P>
! 2081: Generally, an article doesn't contain appendices, but it is possible to add
! 2082: them on explicit request: this is the effect of the question mark before the
! 2083: word Appendices.</P>
! 2084: <P>
! 2085: The Figure, Biblio_citation and Note elements are associated elements. Thus,
! 2086: they are only used in <TT>REFERENCE</TT> statements.</P>
! 2087: <P>
! 2088: Various types of cross-references can be put in paragraphs. They can also be
! 2089: placed the objects which are part of the article, since the cross-references
! 2090: are defined as units (<TT>UNITS</TT>).</P>
! 2091: <P>
! 2092: There is a single restriction to prevent the creation of Ref_note elements
! 2093: within notes.</P>
! 2094: <P>
! 2095: It is worth noting that the S language permits the definition of recursive
! 2096: structures like sections: a section can contain other sections (which are thus
! 2097: at the next lower level of the document tree). Paragraphs are also recursive
! 2098: elements, since a paragraph can contain an enumeration in which each element
! 2099: (<TT>Item</TT>) is composed of paragraphs.</P>
! 2100: </DIV>
! 2101:
! 2102: <DIV class="subsection">
! 2103: <H3>A class of objects: mathematical formulas</H3>
! 2104:
! 2105: <P>
! 2106: The example below defines the <TT>Formula</TT> class which is used in Article
! 2107: documents. This class represents mathematical formulas with a rather simple
! 2108: structure, but sufficient to produce a correct rendition on the screen or
! 2109: printer. To support more elaborate operations (formal or numeric
! 2110: calculations), a finer structure should be defined. This class doesn't use any
! 2111: other class and doesn't define any associated elements or units.</P>
! 2112: <PRE>
! 2113: STRUCTURE Formula;
! 2114: DEFPRES FormulaP;
! 2115:
! 2116: ATTR
! 2117: String_type = Function_name, Variable_name;
! 2118:
! 2119: STRUCT
! 2120: Formula = Expression;
! 2121: Expression = LIST OF (Construction);
! 2122: Construction = CASE OF
! 2123: TEXT; { Simple character string }
! 2124: Index = Expression;
! 2125: Exponent = Expression;
! 2126: Fraction =
! 2127: BEGIN
! 2128: Numerator = Expression;
! 2129: Denominator = Expression;
! 2130: END;
! 2131: Root =
! 2132: BEGIN
! 2133: ? Order = TEXT;
! 2134: Root_Contents = Expression;
! 2135: END;
! 2136: Integral =
! 2137: BEGIN
! 2138: Integration_Symbol = SYMBOL;
! 2139: Lower_Bound = Expression;
! 2140: Upper_Bound = Expression;
! 2141: END;
! 2142: Triple =
! 2143: BEGIN
! 2144: Princ_Expression = Expression;
! 2145: Lower_Expression = Expression;
! 2146: Upper_Expression = Expression;
! 2147: END;
! 2148: Column = LIST [2..*] OF
! 2149: (Element = Expression);
! 2150: Parentheses_Block =
! 2151: BEGIN
! 2152: Opening = SYMBOL;
! 2153: Contents = Expression;
! 2154: Closing = SYMBOL;
! 2155: END;
! 2156: END; { End of Choice Constructor }
! 2157: END { End of Structure Schema }
! 2158: </PRE>
! 2159: <P>
! 2160: This schema defines a single global attribute which allows functions and
! 2161: variables to be distinguished. In the presentation schema, this attribute can
! 2162: be used to choose between roman (for functions) and italic characters (for
! 2163: variables).</P>
! 2164: <P>
! 2165: A formula's structure is that of a mathematical expression, which is itself a
! 2166: sequence of mathematical constructions. A mathematical construction can be
! 2167: either a simple character string, an index, an exponent, a fraction, a root,
! 2168: etc. Each of these mathematical constructions has a sensible structure which
! 2169: generally includes one or more expressions, thus making the formula class's
! 2170: structure definition recursive.</P>
! 2171: <P>
! 2172: In most cases, the roots which appear in the formulas are square roots and
! 2173: their order (2) is not specified. This is why the Order component is marked
! 2174: optional by a question mark. When explicitly requested, it is possible to add
! 2175: an order to a root, for example for cube roots (order = 3).</P>
! 2176: <P>
! 2177: An integral is formed by an integration symbol, chosen by the user (simple
! 2178: integral, double, curvilinear, etc.), and two bounds. A more fine-grained
! 2179: schema would add components for the integrand and the integration variable.
! 2180: Similarly, the Block_Parentheses construction leaves the choice of opening and
! 2181: closing symbols to the user. They can be brackets, braces, parentheses,
! 2182: etc.</P>
! 2183: </DIV>
! 2184: </DIV>
! 2185: <HR>
! 2186: </DIV>
! 2187:
! 2188: <DIV class="chapter">
! 2189: <H1>The P Language</H1>
! 2190:
! 2191:
! 2192: <DIV class="section">
! 2193: <H2>Document presentation</H2>
! 2194:
! 2195: <P>
! 2196: Because of the model adopted for Thot, the presentation of documents is
! 2197: clearly separated from their structure and content. After having presented
! 2198: the logical structure of documents, we now detail the principles implemented
! 2199: for their presentation. The concept of <EM>presentation</EM> encompasses what
! 2200: typographers call the page layout, the composition, and the model of the
! 2201: document. It is the set of operations which display the document on the
! 2202: screen or print it on paper. Like logical structure, document presentation is
! 2203: defined generically with the help of a language, called P.</P>
! 2204:
! 2205: <DIV class="subsection">
! 2206: <H3>Two levels of presentation</H3>
! 2207:
! 2208: <P>
! 2209: The link between structure and presentation is clear: the logical organization
! 2210: of a document is used to carry out its presentation, since the purpose of the
! 2211: presentation is to make evident the organization of the document. But the
! 2212: presentation is equally dependent on the device used to render the document.
! 2213: Certain presentation effects, notably changes of font or character set, cannot
! 2214: be performed on all printers or on all screens. This is why Thot uses a
! 2215: two-level approach, where the presentation is first described in abstract
! 2216: terms, without taking into account each particular device, and then the
! 2217: presentation is realized within the constraints of a given device.</P>
! 2218: <P>
! 2219: Thus, presentation is only described as a function of the structure of the
! 2220: documents and the image that would be produced on an idealized device. For
! 2221: this reason, presentation descriptions do not refer to any device
! 2222: characteristics: they describe <EM>abstract presentations</EM> which can be
! 2223: concretized on different devices.</P>
! 2224: <P>
! 2225: A presentation description also defines a <EM>generic presentation</EM>, since
! 2226: it describes the appearance of a class of documents or objects. This generic
! 2227: presentation must also be applied to document and object instances, each
! 2228: conforming to its generic logical structure, but with all the allowances that
! 2229: were called to mind above: missing elements, constructed elements with other
! 2230: logical structures, etc.</P>
! 2231: <P>
! 2232: In order to preserve the homogeneity between documents and objects,
! 2233: presentation is described with a single set of tools which support the layout
! 2234: of a large document as well as the composition of objects like a graphical
! 2235: figure or mathematical formula. This unity of presentation description tools
! 2236: contrasts with the traditional approach, which focuses more on documents than
! 2237: objects and thus is based on the usual typographic conventions, such as the
! 2238: placement of margins, indentations, vertical spaces, line lengths,
! 2239: justification, font changes, etc.</P>
! 2240: </DIV>
! 2241:
! 2242: <DIV class="subsection">
! 2243: <H3>Boxes</H3>
! 2244:
! 2245: <P>
! 2246: To assure the homogeneity of tools, all presentation in Thot, for documents as
! 2247: well as for the objects which they contain, is based on the notion of the
! 2248: <EM>box</EM>, such as was implemented in T<SUB><BIG>E</BIG></SUB>X.</P>
! 2249: <P>
! 2250: Corresponding to each element of the document is a box, which is the
! 2251: rectangle enclosing the element on the display device (screen or sheet of
! 2252: paper); the outline of this rectangle is normally not visible. The sides of
! 2253: the box are parallel to the sides of the screen or the sheet of paper. By way
! 2254: of example, a box is associated with a character string, a line of text, a
! 2255: page, a paragraph, a title, a mathematical formula, or a table cell.</P>
! 2256: <P>
! 2257: Whatever element it corresponds to, each box possesses four sides and four
! 2258: axes, which we designate as follows (<A href="#boxes">see figure</A>):</P>
! 2259: <DL>
! 2260: <DT><TT> Top</TT></DT>
! 2261: <DD>the upper side,
! 2262: </DD>
! 2263: <DT><TT> Bottom</TT></DT>
! 2264: <DD>the lower side,
! 2265: </DD>
! 2266: <DT><TT> Left</TT></DT>
! 2267: <DD>the left side,
! 2268: </DD>
! 2269: <DT><TT> Right</TT></DT>
! 2270: <DD>the right side,
! 2271: </DD>
! 2272: <DT><TT> VMiddle</TT></DT>
! 2273: <DD>the vertical axis passing through the centerof the box,
! 2274: </DD>
! 2275: <DT><TT> HMiddle</TT></DT>
! 2276: <DD>the horizontal axis passing through the centerof the box,
! 2277: </DD>
! 2278: <DT><TT> VRef</TT></DT>
! 2279: <DD>the vertical reference axis,
! 2280: </DD>
! 2281: <DT><TT> HRef</TT></DT>
! 2282: <DD>the horizontal reference axis.
! 2283: </DD>
! 2284: </DL>
! 2285:
! 2286: <DIV class="figure">
! 2287: <HR>
! 2288: <PRE>
! 2289: Left VRef VMiddle Right
! 2290: : :
! 2291: Top -----------------------------
! 2292: | : : |
! 2293: | : : |
! 2294: | : : |
! 2295: | : : |
! 2296: | : : |
! 2297: HMiddle ..|...........................|..
! 2298: | : : |
! 2299: | : : |
! 2300: HRef ..|...........................|..
! 2301: | : : |
! 2302: | : : |
! 2303: Bottom -----------------------------
! 2304: : :
! 2305: </PRE>
! 2306: <P align=center>
! 2307: <EM><A name="boxes">The sides and axes of boxes</A><EM></EM></EM></P>
! 2308: <HR>
! 2309: </DIV>
! 2310: <P>
! 2311: The principal role of boxes is to set the extent and position of the images of
! 2312: the different elements of a document with respect to each other on the
! 2313: reproduction device. This is done by defining relations between the boxes of
! 2314: different elements which give relative extents and positions to these
! 2315: boxes.</P>
! 2316: <P>
! 2317: There are three types of boxes:</P>
! 2318: <UL>
! 2319: <LI>boxes corresponding to structural elements of the document,
! 2320: <LI>presentation boxes,
! 2321: <LI>page layout boxes.
! 2322: </UL>
! 2323: <P>
! 2324: <STRONG>Boxes corresponding to structural elements of the document</STRONG>
! 2325: are those which linked to each of the elements (base or structured) of the
! 2326: logical structure of the document. Such a box contains all the contents of
! 2327: the element to which it corresponds (there is an exception: see rules
! 2328: <TT>VertOverflow</TT> and <TT>HorizOverflow</TT>). These boxes form a
! 2329: tree-like structure, identical to that of the structural elements to which
! 2330: they correspond. This tree expresses the inclusion relationships between the
! 2331: boxes: a box includes all the boxes of its subtree. On the other hand, there
! 2332: are no predefined rules for the relative positions of the included boxes. If
! 2333: they are at the same level, they can overlap, be contiguous, or be disjoint.
! 2334: The rules expressed in the generic presentation specify their relative
! 2335: positions.</P>
! 2336: <P>
! 2337: <STRONG>Presentation boxes</STRONG> represent elements which are not found in
! 2338: the logical structure of the document but which are added to meet the needs of
! 2339: presentation. These boxes are linked to the elements of the logical structure
! 2340: that are best suited to bringing them out. For example, they are used to add
! 2341: the character string ``Summary:'' before the summary in the presentation of a
! 2342: report or to represent the fraction bar in a formula, or also to make the
! 2343: title of a field in a form appear. These elements have no role in the logical
! 2344: structure of the document: the presence of a Summary element in the document
! 2345: does not require the creation of another structural object to hold the word
! 2346: ``Summary''. Similarly, if a Fraction element contains both a Numerator
! 2347: element and a Denominator element, the fraction bar has no purpose
! 2348: structurally. On the other hand, these elements of the presentation are
! 2349: important for the reader of the reproduced document or for the user of an
! 2350: editor. This is why they must appear in the document's image. It is the
! 2351: generic presentation which specifies the presentation boxes to add by
! 2352: indicating their content (a base element for which the value is specified) and
! 2353: the position that they must take in the tree of boxes. During editing, these
! 2354: boxes cannot be modified by the user.</P>
! 2355: <P>
! 2356: <STRONG>Page layout boxes</STRONG> are boxes created implicitly by the page
! 2357: layout rules. These rules indicate how the contents of a structured element
! 2358: must be broken into lines and pages. In contrast to presentation boxes, these
! 2359: line and page boxes do not depend on the logical structure of the document,
! 2360: but rather on the physical constraints of the reproduction services: character
! 2361: size, height and width of the window on the screen or of the sheet of
! 2362: paper.</P>
! 2363: </DIV>
! 2364:
! 2365: <DIV class="subsection">
! 2366: <H3>Views and visibility</H3>
! 2367:
! 2368: <P>
! 2369: One of the operations that one might wish to perform on a document is to view
! 2370: it is different ways. For this reason, it is possible to define several
! 2371: <EM>views</EM> for the same document, or better yet, for all documents of the
! 2372: same class. A view is not a different presentation of the document, but
! 2373: rather a filter which only allows the display of certain parts of the
! 2374: document. For example, it might be desirable to see only the titles of
! 2375: chapters and sections in order to be able to move rapidly through the
! 2376: document. Such a view could be called a ``table of contents''. It might also
! 2377: be desirable to see only the mathematical formulas of a document in order to
! 2378: avoid being distracted by the non-mathematical aspects of the document. A
! 2379: ``mathematics'' view could provide this service.</P>
! 2380: <P>
! 2381: Views, like presentation, are based on the generic logical structure. Each
! 2382: document class, and each generic presentation, can be provided with views
! 2383: which are particularly useful for that class or presentation. For each view,
! 2384: the <EM>visibility</EM> of elements is defined, indicated whether or not the
! 2385: elements must be presented to the user. The visibility is calculated as a
! 2386: function of the type of the elements or their hierarchical position in the
! 2387: structure of the document. Thus, for a table of contents, all the ``Chapter
! 2388: Title'' and ``Section Title'' elements are made visible. However, the
! 2389: hierarchical level could be used to make the section titles invisible below a
! 2390: certain threshold level. By varying this threshold, the granularity of the
! 2391: view can be varied. In the ``mathematics'' view, only Formula elements would
! 2392: be made visible, no matter what their hierarchical level.</P>
! 2393: <P>
! 2394: Because views are especially useful for producing a synthetic image of the
! 2395: document, it is necessary to adapt the presentation of the elements to the
! 2396: view in which they appear. For example, it is inappropriate to have a page
! 2397: break before every chapter title in the table of contents. Thus, generic
! 2398: presentations take into account the possible views and permit each element
! 2399: type's presentation to vary according the view in which its image appears.</P>
! 2400: <P>
! 2401: <A name="views">Views</A> are also used, when editing documents, to display
! 2402: the associated elements. So, in addition to the primary view of the document,
! 2403: there can be a ``notes'' view and a ``figures'' view which contain,
! 2404: respectively, the associated elements of the Note and Figure types. In this
! 2405: way, it is possible to see simultaneously the text which refers to these
! 2406: elements and the elements themselves, even if they will be separated when
! 2407: printed.</P>
! 2408: </DIV>
! 2409:
! 2410: <DIV class="subsection">
! 2411: <H3>Pages</H3>
! 2412:
! 2413: <P>
! 2414: Presentation schemas can be defined which display the document as a long
! 2415: scroll, without page breaks. This type of schema is particularly well-suited
! 2416: to the initial phase of work on a document, where jumps from page to page
! 2417: would hinder composing and reading the document on a screen. In this case,
! 2418: the associated elements (such as notes), which are normally displayed in the
! 2419: page footer, are presented in a separate window. But, once the document is
! 2420: written, it may be desirable to display the document on the screen in the same
! 2421: manner in which it will be printed. So, the presentation schema must define
! 2422: pages.</P>
! 2423: <P>
! 2424: The P language permits the specification of the dimensions of pages as well as
! 2425: their composition. It is possible to generate running titles, page numbers,
! 2426: zones at the bottom of the page for notes, etc. The editor follows this model
! 2427: and inserts page break marks in the document which are used during printing,
! 2428: insuring that the pages on paper are the same as on the screen.</P>
! 2429: <P>
! 2430: Once a document has been edited with a presentation schema defining pages, it
! 2431: contains page marks. But it is always possible to edit the document using a
! 2432: schema without pages. In this case, the page marks are simply ignored by the
! 2433: editor. They are considered again as soon as a schema with pages is used.
! 2434: Thus, the user is free to choose between schemas with and without pages.</P>
! 2435: <P>
! 2436: Thot treats the page break, rather than the page itself, as a box. This page
! 2437: break box contains all the elements of one page's footer, a rule marking the
! 2438: edge of this page, and all the elements of the next page's header. The
! 2439: elements of the header and footer can be running titles, page number,
! 2440: associated elements (notes, for example), etc. All these elements, as well as
! 2441: their content and graphical appearance, are defined by the generic
! 2442: presentation.</P>
! 2443: </DIV>
! 2444:
! 2445: <DIV class="subsection">
! 2446: <H3>Numbering</H3>
! 2447:
! 2448: <P>
! 2449: Many elements are numbered in documents: pages, chapters, sections, formulas,
! 2450: theorems, notes, figures, bibliographic references, exercises, examples,
! 2451: lemmas, etc. Because Thot has a notion of logical structure, all of these
! 2452: numbers (with the exception of pages) are redundant with information implicit
! 2453: in the logical structure of the document. Such numbers are simply a way to
! 2454: make the structure of the document more visible. So, they are part of the
! 2455: document's presentation and are calculated by the editor from the logical
! 2456: structure. The structure does not contain numbers as such; it only defines
! 2457: relative structural positions between elements, which serve as ordering
! 2458: relations on these elements.</P>
! 2459: <P>
! 2460: If the structure schema defines the body of a document as a sequence of at
! 2461: least two chapters:</P>
! 2462: <PRE>
! 2463: Body = LIST [2..*] OF Chapter ;
! 2464: </PRE>
! 2465: <P>
! 2466: the sequence defined by the list constructor is ordered and eachchapter can be
! 2467: assigned a number based on its rank in the Body list.Therefore, all elements
! 2468: contained in lists a the structure of adocument can be numbered, but they are
! 2469: not the only ones. The treestructure induced by the aggregate, list, and
! 2470: choice constructors(excluding references) defines a total order on the
! 2471: elements of thedocument's primary structure. So, it is possible to define
! 2472: anumbering which uses this order, filtering elements according to theirtype so
! 2473: that only certain element types are taken into account in thenumbering. In
! 2474: this way, it possible to number all the theorems andlemmas of a chapter in the
! 2475: same sequence of numbers, even when theyare not part of the same list
! 2476: constructor and appear at differentlevels of the document's tree. By changing
! 2477: the filter, they can benumbered separately: one sequence of numbers for
! 2478: theorems, another forthe lemmas.</P>
! 2479: <P>
! 2480: Associated elements pose a special problem, since they are not part of the
! 2481: document's primary structure, but are attached only by references, which
! 2482: violate the total order of the document. Then, these associated elements are
! 2483: frequently numbered, precisely because the number is an effective way to
! 2484: visualize the reference. In order to resolve this problem, Thot implicitly
! 2485: defines a list constructor for each type of associated element, gathering
! 2486: together (and ordering) these elements. Thus, the associated elements can be
! 2487: numbered by type.</P>
! 2488: <P>
! 2489: Since they are calculated from the document's logical structure and only for
! 2490: the needs of the presentation, numbers are presentation elements, described by
! 2491: presentation boxes, just like the fraction bar or the word ``Summary''.
! 2492: Nevertheless, numbers differ from these other boxes because their content
! 2493: varies from instance to instance, even though they are of the same type,
! 2494: whereas all fraction bars are horizontal lines and the same word ``Summary''
! 2495: appears at the head of every document's summary.</P>
! 2496: </DIV>
! 2497:
! 2498: <DIV class="subsection">
! 2499: <H3>Presentation parameters</H3>
! 2500:
! 2501: <P>
! 2502: The principal parameters which determine document presentation are the
! 2503: <EM>positions</EM> and <EM>dimensions</EM> of boxes, the <EM>font</EM>, the
! 2504: <EM>style</EM>, the <EM>size</EM>, the <EM>underlining</EM> and the
! 2505: <EM>color</EM> of their content. From these parameters, and some others of
! 2506: less importance, it is possible to represent the usual typographic parameters
! 2507: for the textual parts of the document. These same parameters can be used to
! 2508: describe the geometry of the non-textual elements, even though they are
! 2509: two-dimensional elements unlike the text, which is linear.</P>
! 2510: <P>
! 2511: As we have already seen, the positions of the boxes always respect the rule
! 2512: of enclosure: a box in the tree encloses all the boxes of the next lower level
! 2513: which are attached to it. The positional parameters permit the specification
! 2514: of the position of each box in relation to the enclosing box or to its sibling
! 2515: boxes (boxes directly attached to the same enclosing box in the tree of
! 2516: boxes).</P>
! 2517: <P>
! 2518: The presentation parameters also provide control over the dimensions of the
! 2519: boxes. The dimensions of a box can depend either on its content or on its
! 2520: context (its sibling boxes and the enclosing box). Each dimension (height or
! 2521: width) can be defined independently of the other.</P>
! 2522: <P>
! 2523: Because of the position and dimension parameters, it is possible to do the
! 2524: same things that are normally done in typography by changing margins, line
! 2525: lengths, and vertical or horizontal skips. This approach can also align or
! 2526: center elements and groups of elements.</P>
! 2527: <P>
! 2528: In contrast to the position and dimension parameters, the font, style, size,
! 2529: underlining, and color do not concern the box itself (the rectangle delimiting
! 2530: the element), but its content. These parameters indicate the typographic
! 2531: attributes which must be applied to the text contained in the box, and by
! 2532: extension, to all base elements.</P>
! 2533: <P>
! 2534: For text, the font parameter is used to change the family of characters
! 2535: (Times, Helvetica, Courier, etc.); the style is used to obtain italic or
! 2536: roman, bold or light characters; the size determines the point size of the
! 2537: characters; underlining defines the type and thickness of the lines drawn
! 2538: above, below, or through the characters.</P>
! 2539: <P>
! 2540: For graphics, the line style parameter can be either solid, dotted, or dashed;
! 2541: the line thickness parameter controls the width of the lines; the fill pattern
! 2542: parameter determines how closed geometric figures must be filled.</P>
! 2543: <P>
! 2544: While some of the parameters which determine the appearance of a box's
! 2545: contents make sense only for one content type (text or graphic), other
! 2546: parameters apply to all content types: these are the color parameters. These
! 2547: indicate the color of lines and the background color.</P>
! 2548: </DIV>
! 2549: </DIV>
! 2550:
! 2551: <DIV class="section">
! 2552: <H2><A name="langp">Presentation description language</A></H2>
! 2553:
! 2554: <P>
! 2555: A generic presentation defines the values of presentation parameters (or the
! 2556: way to calculate those values) for a generic structure, or more precisely, for
! 2557: all the element types and all the global and local attributes defined in that
! 2558: generic structure. This definition of the presentation parameters is made
! 2559: with the P language. A program written in this language, that is a generic
! 2560: presentation expressed in P, is call a <EM>presentation schema</EM>. This
! 2561: section describes the syntax and semantics of the language, using the same <A
! 2562: href="#metalang">meta-language</A> as was used for the definition of the S
! 2563: language.</P>
! 2564: <P>
! 2565: Recall that it is possible to write many different presentation schemas for
! 2566: the same class of documents or objects. This allows users to choose for a
! 2567: document the graphical appearance which best suits their type of work or
! 2568: their personal taste.</P>
! 2569:
! 2570: <DIV class="subsection">
! 2571: <H3>The organization of a presentation schema</H3>
! 2572:
! 2573: <P>
! 2574: A presentation schema begins with the word <TT>PRESENTATION</TT> and ends with
! 2575: the word <TT>END</TT>. The word <TT>PRESENTATION</TT> is followed by the name
! 2576: of the generic structure to which the presentation will be applied. This name
! 2577: must be the same as that which follows the keyword <TT>STRUCTURE</TT> in the
! 2578: structure schema associated with the presentation schema.</P>
! 2579: <P>
! 2580: After this declaration of the name of the structure, the following sections
! 2581: appear (in order):</P>
! 2582: <UL>
! 2583: <LI>Declarations of
! 2584: <UL>
! 2585: <LI>all views,
! 2586: <LI>printed views,
! 2587: <LI>counters,
! 2588: <LI>presentation constants,
! 2589: <LI>variables,
! 2590: </UL>
! 2591: <LI>default presentation rules,
! 2592: <LI>presentation box and page layout box definitions,
! 2593: <LI>presentation rules for structured elements,
! 2594: <LI>presentation rules for attributes,
! 2595: <LI>rules for transmitting values to attributes of included documents.
! 2596: </UL>
! 2597: <P>
! 2598: Each of these sections is introduced by a keyword which is followed by a
! 2599: sequence of declarations. Every section is optional.</P>
! 2600: <PRE>
! 2601: SchemaPres ='PRESENTATION' ElemID ';'
! 2602: [ 'VIEWS' ViewSeq ]
! 2603: [ 'PRINT' PrintViewSeq ]
! 2604: [ 'COUNTERS' CounterSeq ]
! 2605: [ 'CONST' ConstSeq ]
! 2606: [ 'VAR' VarSeq ]
! 2607: [ 'DEFAULT' ViewRuleSeq ]
! 2608: [ 'BOXES' BoxSeq ]
! 2609: [ 'RULES' PresentSeq ]
! 2610: [ 'ATTRIBUTES' PresAttrSeq ]
! 2611: [ 'TRANSMIT' TransmitSeq ]
! 2612: 'END' .
! 2613: ElemID = NAME .
! 2614: </PRE>
! 2615: </DIV>
! 2616:
! 2617: <DIV class="subsection">
! 2618: <H3>Views</H3>
! 2619:
! 2620: <P>
! 2621: Each of the possible views must be declared in the presentation schema. As
! 2622: has <A href="#views">already been described</A>, the presentation rules for an
! 2623: element type can vary according to the view in which the element appears. The
! 2624: name of the view is used to designate the view to which the presentation rules
! 2625: apply (see the <A href="#inkeyword"><TT>IN</TT> instruction</A>). The
! 2626: definition of the view's contents are dispersed throughout the presentation
! 2627: rules attached to the different element types and attributes. The
! 2628: <TT>VIEWS</TT> section is simply a sequence of view names separated by commas
! 2629: and terminated by a semi-colon.</P>
! 2630: <P>
! 2631: One of the view names (and only one) can be followed by the keyword
! 2632: <TT>EXPORT</TT>. This keyword identifies the view which presents the members
! 2633: of the document class in <A href="#skeleton">skeleton form</A>. The graphical
! 2634: appearance and the content of this view is defined just as with other views,
! 2635: but it is useless to specify presentation rules concerning this view for the
! 2636: elements which are not loaded in the skeleton form.</P>
! 2637: <P>
! 2638: It is not necessary to declare any views; in this case there is a single
! 2639: unnamed view. If many views are declared, the first view listed is considered
! 2640: the principal view. The principal view is the one to which all rules that are
! 2641: not preceded by an indication of a view will apply (see the <A
! 2642: href="#inkeyword">instruction <TT>IN</TT></A>).</P>
! 2643: <P>
! 2644: The principal view is the the one which the editor presents on the screen when
! 2645: the user asks to create or edit a document. Thus, it makes sense to put the
! 2646: most frequently used view at the head of the list. But if the structure
! 2647: schema contains <A href="#skeleton">skeleton elements</A> and is loaded in its
! 2648: skeleton form, the view whose name is followed by the keyword <TT>EXPORT</TT>
! 2649: will be opened and no other views can be opened.</P>
! 2650: <PRE>
! 2651: 'VIEWS' ViewSeq
! 2652: ViewSeq = ViewDeclaration
! 2653: < ',' ViewDeclaration > ';' .
! 2654: ViewDeclaration = ViewID [ 'EXPORT' ] .
! 2655: ViewID = NAME .
! 2656: </PRE>
! 2657: <BLOCKQUOTE class="example">
! 2658: <P>
! 2659: <STRONG>Example:</STRONG></P>
! 2660: <P>
! 2661: When editing a report, it might be useful have views of the table ofcontents
! 2662: and of the mathematical formulas, in addition to theprincipal view which shows
! 2663: the document in its entirety. To achievethis, a presentation schema for the
! 2664: Report class would have thefollowing <TT>VIEWS</TT>section:</P>
! 2665: <PRE>
! 2666: VIEWS
! 2667: Full_text, Table_of_contents, Formulas;
! 2668: </PRE>
! 2669: <P>
! 2670: The contents of these views are specified in the presentation rules of the
! 2671: schema.</P>
! 2672: </BLOCKQUOTE>
! 2673: </DIV>
! 2674:
! 2675: <DIV class="subsection">
! 2676: <H3>Print Views</H3>
! 2677:
! 2678: <P>
! 2679: When editing a document, each view is presented in a different window. In
! 2680: addition to the views specified by the <TT>VIEWS</TT> instruction, the user
! 2681: can display the associated elements with one window for each type of
! 2682: associated element.</P>
! 2683: <P>
! 2684: When printing a document, it is possible to print any number of views, chosen
! 2685: from among all the views which the editor can display (views in the strict
! 2686: sense or associated elements). Print views, as well as the order in which
! 2687: they must be printed, are indicated by the <TT>PRINT</TT> instruction. It
! 2688: appears after the <TT>VIEWS</TT> instruction and is formed of the keyword
! 2689: <TT>PRINT</TT> followed by the ordered list of print view names. The print
! 2690: view names are separated by commas and followed by a semi-colon. A print view
! 2691: name is either a view name declared in the <TT>VIEWS</TT> instruction or the
! 2692: name of an associated element type (with an ``s'' added to the end). The
! 2693: associated element must have been declared in the <TT>ASSOC</TT> section of
! 2694: the structure schema.</P>
! 2695: <PRE>
! 2696: 'PRINT' PrintViewSeq
! 2697: PrintViewSeq = PrintView < ',' PrintView > ';' .
! 2698: PrintView = ViewID / ElemID .
! 2699: </PRE>
! 2700: <P>
! 2701: If the <TT>PRINT</TT> instruction is absent, the printing program will print
! 2702: only the principal view (the first view specified by the <TT>VIEWS</TT>
! 2703: instruction or the single, unnamed view when there is no <TT>VIEWS</TT>
! 2704: instruction).</P>
! 2705: <BLOCKQUOTE class="example">
! 2706: <P>
! 2707: <STRONG>Example:</STRONG></P>
! 2708: <P>
! 2709: Consider a Report presentation using the view declarations from thepreceding
! 2710: example. Suppose we want to print the full text and tableof contents views,
! 2711: but not the Formulas view, which is only usefulwhen editing. In addition,
! 2712: suppose that we also want to print thebibliographic citations, which are
! 2713: associated elements (of type<TT>Citation</TT>). A sensible printing order
! 2714: would be to print the full textthen the bibliography and finally the table of
! 2715: contents. To obtainthis result when printing, the presentation schema would
! 2716: say:</P>
! 2717: <PRE>
! 2718: PRINT
! 2719: Full_text, Citations, Table_of_contents;
! 2720: </PRE>
! 2721: </BLOCKQUOTE>
! 2722: </DIV>
! 2723:
! 2724: <DIV class="subsection">
! 2725: <H3>Counters</H3>
! 2726:
! 2727: <P>
! 2728: A presentation has a <EM>counter</EM> for each type of number in the
! 2729: presentation. All counters, and therefore all types of numbers, used in the
! 2730: schema must be declared after the <TT>COUNTERS</TT> keyword.</P>
! 2731: <P>
! 2732: Each counter declaration is composed of a name identifying the counter
! 2733: followed by a colon and the counting function to be applied to the counter.
! 2734: The counter declaration ends with a semi-colon.</P>
! 2735: <P>
! 2736: The counting function indicates how the counter values will be calculated.
! 2737: Three types of counting functions are available. The first type is used to
! 2738: count the elements of a list or aggregate: it assigns to the counter the rank
! 2739: of the element in the list or aggregate. More precisely, the function</P>
! 2740: <PRE>
! 2741: RANK OF ElemID [ LevelAsc ] [ INIT AttrID ]
! 2742: [ 'REINIT' AttrID ]
! 2743: </PRE>
! 2744: <P>
! 2745: indicates that when an element creates, by a creation rule (see the<A
! 2746: href="#creation"><TT>Create</TT> instructions</A>), a presentationbox
! 2747: containing the counter value, this value is the rank of thecreating element,
! 2748: if it is of type <TT>ElemID</TT>, otherwise the rank ofthe first element of
! 2749: type <TT>ElemID</TT>which encloses the creatingelement in the logical
! 2750: structure of the document.</P>
! 2751: <P>
! 2752: The type name can be preceded by a star in the special case where the
! 2753: structure schema defines an element of whose <TT>ElemID</TT> is the same as
! 2754: that of an <A href="#references">inclusion</A> without expansion or with
! 2755: partial expansion. To resolve this ambiguity, the <TT>ElemID</TT> alone
! 2756: refers to the type defined in the structure schema while the <TT>ElemID</TT>
! 2757: preceded by a star refers to the included type.</P>
! 2758: <P>
! 2759: The type name <TT>ElemID</TT> can be followed by an integer. That number
! 2760: represents the relative level, among the ancestors of the creating element, of
! 2761: the element whose rank is asked. If that relative level <I>n</I> is unsigned,
! 2762: the <I>n</I><SUP>th</SUP> element of type <TT>ElemID</TT> encountered when
! 2763: travelling the logical structure from the root to the creating element is
! 2764: taken into account. If the relative level is negative, the logical structure
! 2765: is travelled in the other direction, from the creating element to the
! 2766: root.</P>
! 2767: <P>
! 2768: The function can end with the keyword <TT>INIT</TT> followed by the name of a
! 2769: numeric attribute (and only a numeric attribute). Then, the rank of the first
! 2770: element of the list or aggregate is considered to be the value of this
! 2771: attribute, rather than the default value of 1, and the rank of the other
! 2772: elements is shifted accordingly. The attribute which determines the initial
! 2773: value is searched on the element itself and on its ancestors.</P>
! 2774: <P>
! 2775: The function can end with the keyword <TT>REINIT</TT> followed by the name of
! 2776: a numeric attribute (and only a numeric attribute). Then, if an element to be
! 2777: counted has this attribute, the counter value for this element is the
! 2778: attribute value and the following elements are numbered starting from this
! 2779: value.</P>
! 2780: <P>
! 2781: When the <TT>RANK</TT> function is written</P>
! 2782: <PRE>
! 2783: RANK OF Page [ ViewID ] [ INIT AttrID ]
! 2784: </PRE>
! 2785: <P>
! 2786: (<TT>Page</TT>is a keyword of the P language), the counter takes as itsvalue
! 2787: the number of the page on which the element which creates thepresentation box
! 2788: containing the number appears. This is done as ifthe pages of the document
! 2789: form a list for each view. The counter onlytakes into account the pages of
! 2790: the relevant view, that is the viewdisplaying the presentation box whose
! 2791: contents take the value of thenumber. However, if the keyword <TT>Page</TT>is
! 2792: followed by the name of aview (between parentheses), it is the pages of that
! 2793: view that aretaken into account. As in the preceding form, the
! 2794: <TT>RANK</TT>functionapplied to pages can end with the <TT>INIT</TT>keyword
! 2795: followed the nameof a numeric attribute which sets the value of the first
! 2796: page'snumber. This attribute must be a local attribute of the documentitself,
! 2797: and not of one of its components.</P>
! 2798: <P>
! 2799: The second counting function is used to count the occurrences of a certain
! 2800: element type in a specified context. The instruction</P>
! 2801: <PRE>
! 2802: SET n ON Type1 ADD m ON Type2 [ INIT AttrID ]
! 2803: </PRE>
! 2804: <P>
! 2805: says that when the document is traversed from beginning to end (in theorder
! 2806: induced by the logical structure), the counter is assigned thevalue
! 2807: <TT>n</TT>each time an element of type <TT>Type1</TT>is encountered, nomatter
! 2808: what the current value of the counter, and the value <TT>m</TT>isadded to the
! 2809: current value of the counter each time an element of type<TT>Type2</TT>is
! 2810: encountered.</P>
! 2811: <P>
! 2812: As with the <TT>RANK</TT> function, the type names can be preceded by a star
! 2813: to resolve the ambiguity of included elements.</P>
! 2814: <P>
! 2815: If the function ends with the keyword <TT>INIT</TT> followed by the name of an
! 2816: attribute and if the document possesses this attribute, the value of this
! 2817: attribute is used in place of <TT>n</TT>. The attribute must be numeric. It
! 2818: is searched on the element itself and on its ancestors.</P>
! 2819: <P>
! 2820: This function can also be used with the <TT>Page</TT> keyword in the place of
! 2821: <TT>Type1</TT> or <TT>Type2</TT>. In the first case, the counter is
! 2822: reinitialized on each page with the value <TT>n</TT>, while in the second
! 2823: case, it is incremented by <TT>m</TT> on each page. As with the preceding
! 2824: counting function, the word <TT>Page</TT> can be followed by a name between
! 2825: parentheses. In this case, the name specifies a view whose pages are taken
! 2826: into account.</P>
! 2827: <P>
! 2828: The definition of a counter can contain several <TT>SET</TT> functions and
! 2829: several <TT>ADD</TT> functions, each with a different value. The total number
! 2830: of counting functions must not be greater than 6.</P>
! 2831: <P>
! 2832: The third counting function is used to count the elements of a certain type
! 2833: encountered when travelling from the creating element to the root of the
! 2834: logical structure. The creating element is included if it is of that type.
! 2835: That function is written</P>
! 2836: <PRE>
! 2837: RLEVEL OF Type
! 2838: </PRE>
! 2839: <P>
! 2840: where <TT>Type</TT>represents the type of the elements to be counted.</P>
! 2841: <P>
! 2842: The formal definition of counter declarations is:</P>
! 2843: <PRE>
! 2844: 'COUNTERS' CounterSeq
! 2845: CounterSeq = Counter < Counter > .
! 2846: Counter = CounterID ':' CounterFunc ';' .
! 2847: CounterID = NAME .
! 2848: CounterFunc = 'RANK' 'OF' TypeOrPage [ SLevelAsc ]
! 2849: [ 'INIT' AttrID ] [ 'REINIT' AttrID ] /
! 2850: SetFunction < SetFunction >
! 2851: AddFunction < AddFunction >
! 2852: [ 'INIT' AttrID ] /
! 2853: 'RLEVEL' 'OF' ElemID .
! 2854: SLevelAsc = [ '-' ] LevelAsc .
! 2855: LevelAsc = NUMBER .
! 2856: SetFunction = 'SET' CounterValue 'ON' TypeOrPage .
! 2857: AddFunction = 'ADD' CounterValue 'ON' TypeOrPage .
! 2858: TypeOrPage = 'Page' [ '(' ViewID ')' ] /
! 2859: [ '*' ] ElemID .
! 2860: CounterValue = NUMBER .
! 2861: </PRE>
! 2862: <BLOCKQUOTE class="example">
! 2863: <P>
! 2864: <STRONG>Example:</STRONG></P>
! 2865: <P>
! 2866: If the body of a chapter is defined as a sequence of sections in thestructure
! 2867: schema:</P>
! 2868: <PRE>
! 2869: Chapter_body = LIST OF (Section =
! 2870: BEGIN
! 2871: Section_Title = Text;
! 2872: Section_Body = Paragraphs;
! 2873: END
! 2874: );
! 2875: </PRE>
! 2876: <P>
! 2877: the section counter is declared:</P>
! 2878: <PRE>
! 2879: SectionCtr : RANK OF Section;
! 2880: </PRE>
! 2881: <P>
! 2882: and the display of the section number before the section title isobtained by a
! 2883: <A href="#creation"><TT>CreateBefore</TT> rule</A>attached the
! 2884: <TT>Section_Title</TT>type, which creates a presentationbox whose content is
! 2885: the value of the <TT>SectionCtr</TT>counter (seethe <A
! 2886: href="#content"><TT>Content</TT> instruction</A>).</P>
! 2887: <P>
! 2888: In order to number the formulas separately within each chapter, the formula
! 2889: counter is declared:</P>
! 2890: <PRE>
! 2891: FormulaCtr : SET 0 ON Chapter ADD 1 ON Formula;
! 2892: </PRE>
! 2893: <P>
! 2894: and the display of the formula number in the right margin, alongsideeach
! 2895: formula, is obtained by a <TT>CreateAfter</TT>instruction attachedto the
! 2896: <TT>Formula</TT>type, which creates a presentation box whosecontent is the
! 2897: value of the <TT>FormulaCtr</TT>counter.</P>
! 2898: <P>
! 2899: To number the page chapter by chapter, with the first page of each chapter
! 2900: having the number 1, the counter definition would be</P>
! 2901: <PRE>
! 2902: ChapterPageCtr : SET 0 ON Chapter ADD 1 ON Page;
! 2903: </PRE>
! 2904: <P>
! 2905: If there is also a chapter counter</P>
! 2906: <PRE>
! 2907: ChapterCtr : RANK OF Chapter;
! 2908: </PRE>
! 2909: <P>
! 2910: the <A href="#content">content</A>of a presentation box createdat the top of
! 2911: each page could be defined as:</P>
! 2912: <PRE>
! 2913: Content : (VALUE(ChapterCtr, URoman) TEXT '-'
! 2914: VALUE(ChapterPageCtr, Arabic));
! 2915: </PRE>
! 2916: <P>
! 2917: Thus, the presentation box contains the number of the chapter inupper-case
! 2918: romannumerals followed by a hyphen and the number of the page within
! 2919: thechapter in arabic numerals.</P>
! 2920: </BLOCKQUOTE>
! 2921: <BLOCKQUOTE class="example">
! 2922: <P>
! 2923: <STRONG>Example:</STRONG></P>
! 2924: <P>
! 2925: To count tables and figures together in a document of the chaptertype, a
! 2926: counter could be defined using:</P>
! 2927: <PRE>
! 2928: CommonCtr : SET 0 ON Chapter ADD 1 ON Table
! 2929: ADD 1 ON Figure;
! 2930: </PRE>
! 2931: </BLOCKQUOTE>
! 2932: </DIV>
! 2933:
! 2934: <DIV class="subsection">
! 2935: <H3><A name="presconst">Presentation constants</A></H3>
! 2936:
! 2937: <P>
! 2938: Presentation constants are used in the definition of the content of
! 2939: presentation boxes. This content is used in <A href="#variables">variable
! 2940: definitions</A> and in the <A href="#content"><TT>Content</TT> rule</A>. The
! 2941: only presentation constants which can be used are character strings,
! 2942: mathematical symbols, graphical elements, and images, that is to say, base
! 2943: elements.</P>
! 2944: <P>
! 2945: Constants can be defined directly in the variables or presentation boxes
! 2946: (<TT>Content</TT> rule) which use them. But it is only necessary them to
! 2947: declare once, in the constant declaration section, even though they are used
! 2948: in many variables or boxes. Thus, each declared constant has a name, which
! 2949: allows it to be designated whenever it is used, a type (one of the four base
! 2950: types) and a value (a character string or a single character for mathematical
! 2951: symbols and graphical elements).</P>
! 2952: <P>
! 2953: The constant declarations appear after the keyword <TT>CONST</TT>. Each
! 2954: declaration is composed of the name of the constant, an equals sign, a keyword
! 2955: representing its type (<TT>Text</TT>, <TT>Symbol</TT>, <TT>Graphics</TT> or
! 2956: <TT>Picture</TT>) and the string representing its value. A semi-colon
! 2957: terminates each declaration.</P>
! 2958: <P>
! 2959: In the case of a character string, the keyword <TT>Text</TT> can be followed
! 2960: by the name of an alphabet (for example, <TT>Greek</TT> or <TT>Latin</TT>) in
! 2961: which the constant's text should be expressed. If the alphabet name is
! 2962: absent, the Latin alphabet is used. When the alphabet name is present, only
! 2963: the first letter of the alphabet name is interpreted. Thus, the words
! 2964: <TT>Greek</TT> and <TT>Grec</TT> designate the same alphabet. In current
! 2965: versions of Thot, only the Greek and Latin alphabets are available.</P>
! 2966: <PRE>
! 2967: 'CONST' ConstSeq
! 2968: ConstSeq = Const < Const > .
! 2969: Const = ConstID '=' ConstType ConstValue ';' .
! 2970: ConstID = NAME .
! 2971: ConstType ='Text' [ Alphabet ] / 'Symbol' /
! 2972: 'Graphics' / 'Picture' .
! 2973: ConstValue = STRING .
! 2974: Alphabet = NAME .
! 2975: </PRE>
! 2976: <P>
! 2977: For character strings in the Latin alphabet (ISO-Latin 1 character set),
! 2978: characters having codes higher than 127 (decimal) are represented by their
! 2979: code in octal.</P>
! 2980: <P>
! 2981: In the case of a symbol or graphical element, the value only contains a single
! 2982: character, between apostrophes, which indicates the form of the element which
! 2983: must be drawn in the box whose content is the constant. The symbol or
! 2984: graphical element takes the dimensions of the box, which are determined by the
! 2985: <TT>Height</TT> and <TT>Width</TT> rules. See <A href="#symbolcoding">table of
! 2986: codes</A> for the symbols and graphical elements.</P>
! 2987: <BLOCKQUOTE class="example">
! 2988: <P>
! 2989: <STRONG>Example:</STRONG></P>
! 2990: <P>
! 2991: The constants ``Summary:'' and fraction bar, which were describedearlier, are
! 2992: declared:</P>
! 2993: <PRE>
! 2994: CONST
! 2995: SummaryConst = Text 'Summary:';
! 2996: Bar = Graphics 'h';
! 2997: </PRE>
! 2998: </BLOCKQUOTE>
! 2999: </DIV>
! 3000:
! 3001: <DIV class="subsection">
! 3002: <H3><A name="variables">Variables</A></H3>
! 3003:
! 3004: <P>
! 3005: Variables permit the definition of computed content for presentation boxes. A
! 3006: variable is associated with a presentation box by a <TT>Content</TT> rule; but
! 3007: before being used in a <TT>Content</TT> rule, a variable can be defined in the
! 3008: <TT>VAR</TT> section. It is also possible to define a variable at the time of
! 3009: its use in a <TT>Content</TT> rule, as can be done with a constant.</P>
! 3010: <P>
! 3011: A variable has a name and a value which is a character string resulting from
! 3012: the concatenation of the values of a sequence of functions. Each variable
! 3013: declaration is composed of the variable name followed by a colon and the
! 3014: sequence of functions which produces its value, separated by spaces. Each
! 3015: declaration is terminated by a semi-colon.</P>
! 3016: <PRE>
! 3017: 'VAR' VarSeq
! 3018: VarSeq = Variable < Variable > .
! 3019: Variable = VarID ':' FunctionSeq ';' .
! 3020: VarID = NAME .
! 3021: FunctionSeq = Function < Function > .
! 3022: </PRE>
! 3023: <P>
! 3024: Several functions are available. The first two return, in the form of a
! 3025: character string, the current date. <TT>DATE</TT> returns the date in
! 3026: English, while <TT>FDATE</TT> returns the date in french.</P>
! 3027: <P>
! 3028: Two other functions, <TT>DocName</TT> and <TT>DirName</TT>, return the
! 3029: document name and the directory where the document is stored.</P>
! 3030: <P>
! 3031: Function <TT>ElemName</TT> returns the type of the element which created the
! 3032: presentation box whose contents are the variable.</P>
! 3033: <P>
! 3034: Another function simply returns the value of a presentation constant. For any
! 3035: constant declared in the <TT>CONST</TT> section, it is sufficient to give the
! 3036: name of the constant. Otherwise, the type and value of the constant must be
! 3037: given, using the same form as in a <A href="#presconst">constant
! 3038: declaration</A>. If the constant is not of type text, (types <TT>Symbol</TT>,
! 3039: <TT>Graphics</TT> or <TT>Picture</TT>), it must be alone in the variable
! 3040: definition; only constants of type <TT>Text</TT> can be mixed with other
! 3041: functions.</P>
! 3042: <P>
! 3043: It is also possible to obtain the value of an attribute, simply by mentioning
! 3044: the attribute's name. The value of this function is the value of the
! 3045: attribute for the element which created the presentation box whose contents
! 3046: are the variable. If the creating element does not have the indicated
! 3047: attribute, the value is an empty string. In the case of a numeric attribute,
! 3048: the attribute is translated into a decimal number in arabic numerals. If
! 3049: another form is desired, the <TT>VALUE</TT> function must be used.</P>
! 3050: <P>
! 3051: The last available function returns, as a character string, the value of a
! 3052: counter, an attribute or a page number. This value can be presented in
! 3053: different styles. The keyword <TT>VALUE</TT> is followed (between
! 3054: parentheses) by the name of the counter, the name of the attribute, or the
! 3055: keyword <TT>PageNumber</TT> and the desired style, the two parameters being
! 3056: separated by a comma. The style is a keyword which indicates whether the
! 3057: value should be presented in arabic numerals (<TT>Arabic</TT>), lower-case
! 3058: roman numerals (<TT>LRoman</TT>), or upper-case roman numerals
! 3059: (<TT>URoman</TT>), or by an upper-case letter (<TT>Uppercase</TT>) or
! 3060: lower-case letter (<TT>Lowercase</TT>).</P>
! 3061: <P>
! 3062: For a page counter, the keyword <TT>PageNumber</TT> can be followed, between
! 3063: parentheses, by the name of the view from which to obtain the page number. By
! 3064: default, the first view declared in the <TT>VIEWS</TT> section is used. The
! 3065: value obtained is the number of the page on which is found the element that is
! 3066: using the variable in a <TT>Content</TT> rule.</P>
! 3067: <P>
! 3068: For an ordinary counter, the name of the counter can be preceded by the
! 3069: keyword <TT>MaxRangeVal</TT> or <TT>MinRangeVal</TT>. These keywords mean
! 3070: that the value returned by the function is the maximum (minimum resp.) value
! 3071: taken by the counter in the whole document, not the value for the element
! 3072: concerned by the function.</P>
! 3073: <PRE>
! 3074: Function = 'DATE' / 'FDATE' /
! 3075: 'DocName' / 'DirName' /
! 3076: 'ElemName' / 'AttributeName' /
! 3077: ConstID / ConstType ConstValue /
! 3078: AttrID /
! 3079: 'VALUE' '(' PageAttrCtr ','
! 3080: CounterStyle ')' .
! 3081: PageAttrCtr = 'PageNumber' [ '(' ViewID ')' ] /
! 3082: [ MinMax ] CounterID / AttrID .
! 3083: CounterStyle = 'Arabic' / 'LRoman' / 'URoman' /
! 3084: 'Uppercase' / 'Lowercase' .
! 3085: MinMax = 'MaxRangeVal' / 'MinRangeVal' .
! 3086: </PRE>
! 3087: <BLOCKQUOTE class="example">
! 3088: <P>
! 3089: <STRONG>Example:</STRONG></P>
! 3090: <P>
! 3091: To make today's date appear at the top of the first page of a report,a <A
! 3092: href="#creation"><TT>CREATE</TT> rule</A>associated with theReport_Title
! 3093: element type generates a presentation box whose content(specified by the
! 3094: <TT>Content</TT>rule of that presentation box) isthe variable:</P>
! 3095: <PRE>
! 3096: VAR
! 3097: Todays_date : TEXT 'Version of ' DATE;
! 3098: </PRE>
! 3099: <P>
! 3100: To produce, before each section title, the chapter number (in upper-case roman
! 3101: numerals) followed by the section number (in arabic numerals), two counters
! 3102: must be defined:</P>
! 3103: <PRE>
! 3104: COUNTERS
! 3105: ChapterCtr : RANK OF Chapter;
! 3106: SectionCtr : RANK OF Section;
! 3107: </PRE>
! 3108: <P>
! 3109: and the Section_Title element must create a presentation box whosecontent is
! 3110: the variable</P>
! 3111: <PRE>
! 3112: VAR
! 3113: SectionNum : VALUE (ChapterCtr, URoman) TEXT '-'
! 3114: VALUE (SectionCtr, Arabic);
! 3115: </PRE>
! 3116: <P>
! 3117: In order to make the page number on which each section begins appear in the
! 3118: table of contents view next to the section title, each Section_Title element
! 3119: must create a presentation box, visible only in the table of contents view,
! 3120: whose content is the variable:</P>
! 3121: <PRE>
! 3122: VAR
! 3123: TitlePageNume :
! 3124: VALUE (PageNumber(Full_text), Arabic);
! 3125: </PRE>
! 3126: </BLOCKQUOTE>
! 3127: </DIV>
! 3128:
! 3129: <DIV class="subsection">
! 3130: <H3><A name="defaultpresrules">Default presentation rules</A></H3>
! 3131:
! 3132: <P>
! 3133: In order to avoid having to specify, for each element type defined in the
! 3134: structure schema, values for every one of the numerous presentation
! 3135: parameters, the presentation schema allows the definition of a set of default
! 3136: presentation rules. These rules apply to all the boxes of the elements
! 3137: defined in the structure schema and to the presentation boxes and page layout
! 3138: boxes defined in the presentation schema. Only rules which differ from these
! 3139: default need to be specified in other sections of the presentation schema.</P>
! 3140: <P>
! 3141: For the primary view, the default rules can define every presentation
! 3142: parameter, but not the <A href="#presfunct">presentation functions</A> or the
! 3143: <A href="#breakcond">linebreaking conditions</A> (the <TT>NoBreak1</TT>,
! 3144: <TT>NoBreak2</TT>, and <TT>Gather</TT> rules).</P>
! 3145: <P>
! 3146: In a presentation schema, the default presentation rules section is optional;
! 3147: in this case, the <TT>DEFAULT</TT> keyword is also absent and the following
! 3148: rules are considered to be the default rules:</P>
! 3149: <PRE>
! 3150: Visibility: Enclosing =;
! 3151: VertRef: * . Left;
! 3152: HorizRef: Enclosed . HRef;
! 3153: Height: Enclosed . Height;
! 3154: Width: Enclosed . Width;
! 3155: VertPos: Top = Previous . Bottom;
! 3156: HorizPos: Left = Enclosing . Left;
! 3157: VertOverflow: No;
! 3158: HorizOverflow: No;
! 3159: Size: Enclosing =;
! 3160: Style: Enclosing =;
! 3161: Font: Enclosing =;
! 3162: Underline: Enclosing =;
! 3163: Thickness: Enclosing =;
! 3164: Indent: Enclosing =;
! 3165: LineSpacing: Enclosing =;
! 3166: Adjust: Enclosing =;
! 3167: Justify: Enclosing =;
! 3168: Hyphenate: Enclosing =;
! 3169: PageBreak: Yes;
! 3170: LineBreak: Yes;
! 3171: InLine: Yes;
! 3172: Depth: 0;
! 3173: LineStyle: Enclosing =;
! 3174: LineWeight: Enclosing =;
! 3175: FillPattern: Enclosing =;
! 3176: Background: Enclosing =;
! 3177: Foreground: Enclosing =;
! 3178: </PRE>
! 3179: <P>
! 3180: If other values are desired for the default rules, they must be defined
! 3181: explicitly in the default rules section. In fact, it is only necessary to
! 3182: define those default rules which differ from the ones above, since the rules
! 3183: above will be used whenever a rule is not explicitly named.</P>
! 3184: <P>
! 3185: Default rules for views other than the primary view can also be specified.
! 3186: Otherwise, the default rules for the primary views are applied to the other
! 3187: views.</P>
! 3188: <P>
! 3189: Default rules are expressed in the same way as <A href="#presrule">explicit
! 3190: rules for document elements</A>.</P>
! 3191: </DIV>
! 3192:
! 3193: <DIV class="subsection">
! 3194: <H3>Presentation and page layout boxes</H3>
! 3195:
! 3196: <P>
! 3197: The presentation process uses elements which are not part of the logical
! 3198: structure of the document, such as pages (which are the page layout boxes) or
! 3199: alternatively, rules, numbers, or words introducing certain parts of the
! 3200: document, such as ``Summary'', ``Appendices'', ``Bibliography'', etc. (which
! 3201: are presentation boxes).</P>
! 3202: <P>
! 3203: After the word <TT>BOXES</TT>, each presentation or page layout box is defined
! 3204: by its name and a sequence of presentation rules which indicate how they must
! 3205: be displayed. These rules are the same as those which define the boxes
! 3206: associated with element of the logical structure of the document, with a
! 3207: single exception, the <A href="#content"><TT>Content</TT> rule</A> which is
! 3208: used only to specify the content of presentation boxes. The content of boxes
! 3209: associated with elements of the document structure is defined in each document
! 3210: or object and thus is not specified in the presentation schema, which applies
! 3211: to all documents or objects of a class.</P>
! 3212: <P>
! 3213: Among the rules which define a presentation box, certain ones can refer to
! 3214: another presentation box (for example, in their positional rules). If the
! 3215: designated box is defined after the box which designates it, a
! 3216: <TT>FORWARD</TT> instruction followed by the name of the designated box must
! 3217: appear before the designation.</P>
! 3218: <PRE>
! 3219: 'BOXES' BoxSeq
! 3220: BoxSeq = Box < Box > .
! 3221: Box ='FORWARD' BoxID ';' /
! 3222: BoxID ':' ViewRuleSeq .
! 3223: BoxID = NAME .
! 3224: </PRE>
! 3225: </DIV>
! 3226:
! 3227: <DIV class="subsection">
! 3228: <H3>Presentation of structured elements</H3>
! 3229:
! 3230: <P>
! 3231: After the words <TT>RULES</TT>, the presentation schema gives the presentation
! 3232: rules that apply to the elements whose types are defined in the structure
! 3233: schema. Only those rules which differ from the <A
! 3234: href="#defaultpresrules">default</A> must be specified in the <TT>RULES</TT>
! 3235: section.</P>
! 3236: <P>
! 3237: The rule definitions for each element type are composed of the name of the
! 3238: element type (as specified in the structure schema) followed by a colon and
! 3239: the set of rules specific to that type.</P>
! 3240: <P>
! 3241: The type name can be preceded by a star in the special case where the
! 3242: structure schema defines an <A href="#references">inclusion</A> without
! 3243: expansion (or with partial expansion) of a type with the same name as an
! 3244: element of defined in the structure schema.</P>
! 3245: <P>
! 3246: In the case where the element is a <A href="#pairs">mark pair</A>, but only in
! 3247: this case, the type name can be preceded by the keywords <TT>First</TT> or
! 3248: <TT>Second</TT>. These keywords indicate whether the rules that follow apply
! 3249: to the first or second mark of the pair.</P>
! 3250: <PRE>
! 3251: 'RULES' PresentSeq
! 3252: PresentSeq = Present < Present > .
! 3253: Present = [ '*' ] [ FirstSec ] ElemID ':'
! 3254: ViewRuleSeq .
! 3255: FirstSec = 'First' / 'Second' .
! 3256: </PRE>
! 3257: <P>
! 3258: A presentation schema can define presentation rules for base elements, which
! 3259: are defined implicitly in the structure schemas. In the English version of
! 3260: the presentation schema compiler, the base type names are the same as in the S
! 3261: language, but they are terminated by the <TT>_UNIT</TT> suffix:
! 3262: <TT>TEXT_UNIT</TT>, <TT>PICTURE_UNIT</TT>, <TT>SYMBOL_UNIT</TT>,
! 3263: <TT>GRAPHICS_UNIT</TT>. In the French version of the compiler, the base types
! 3264: are: <TT>TEXTE</TT>, <TT>IMAGE</TT>, <TT>SYMBOLE</TT>, <TT>GRAPHIQUE</TT>.
! 3265: Whatever version of the compiler is used, the base type names are written in
! 3266: upper-case letters.</P>
! 3267: </DIV>
! 3268:
! 3269: <DIV class="subsection">
! 3270: <H3><A name="presattributes">Logical attribute presentation</A></H3>
! 3271:
! 3272: <P>
! 3273: After the keyword <TT>ATTRIBUTES</TT>, all attributes which are to have some
! 3274: effect on the presentation of the element to which they are attached must be
! 3275: mentioned, along with the corresponding presentation rules. This is true for
! 3276: both global attributes (which can be attached to all element types) and local
! 3277: attributes (which can only be attached to certain element types).</P>
! 3278: <P>
! 3279: Also mentioned in this section are attributes which imply an effect on
! 3280: elements in the subtree of the element to which they are attached. The
! 3281: presentation of these descendants can be modified as a function of the value
! 3282: of the attribute which they inherit, just as if it was attached to them
! 3283: directly.</P>
! 3284: <P>
! 3285: The specification for each attribute includes the attribute's name, followed
! 3286: by an optional value specification and, after a colon, a set of rules. The
! 3287: set of rules must contain at least one rule.</P>
! 3288: <P>
! 3289: When there is no value specification, the rules are applied to all elements
! 3290: which carry the attribute, no matter what their value. When the rules must
! 3291: only apply when the attribute has certain values, these values must be
! 3292: specified. Thus, the same attribute can appear in the <TT>ATTRIBUTES</TT>
! 3293: section several times, with each appearance having a different value
! 3294: specification. However, reference attributes never have a value specification
! 3295: and, as a result, can only appear once in the <TT>ATTRIBUTES</TT> section.</P>
! 3296: <P>
! 3297: To specify that the presentation rules apply to some of the descendants of the
! 3298: element having the attribute, the name of the affected element type is given,
! 3299: between parentheses, after the attribute name. This way, the presentation
! 3300: rules for the attribute will be applied to the element having the attribute,
! 3301: if it is of the given type, and to all of its descendants of the given type.
! 3302: In the case where this type is a <A href="#pairs">mark pair</A>, but only in
! 3303: this case, the type name can be preceded by the keywords <TT>First</TT> or
! 3304: <TT>Second</TT>. These keywords indicate whether the rules that follow apply
! 3305: to the first or second mark of the pair. If the rule must apply to several
! 3306: different element types, the specification must be repeated for each element
! 3307: type.</P>
! 3308: <P>
! 3309: The specification of values for which the presentation rules will be applied
! 3310: varies according to the type of the attribute:</P>
! 3311: <DL>
! 3312: <DT>numeric attribute</DT>
! 3313: <DD>If the rules are to apply for one value ofthe attribute, then the
! 3314: attribute name is followed by an equals signand this value. If the rules are
! 3315: to apply for all values less than(or greater than) a threshold value,
! 3316: non-inclusive, the attribute namefollowed by a '<' sign (or a '>' sign,
! 3317: respectively) andthe threshold value. If the rules must apply to a range of
! 3318: values,the attribute name is followed by the word '<TT>IN</TT>' and the
! 3319: twobounds of the range, enclosed in brackets and separated by two
! 3320: periods('<TT>..</TT>'). In the case of ranges, the values of the bounds
! 3321: areincluded in the range.
! 3322: <P>
! 3323: The threshold value in the comparisons can be the value of an attribute
! 3324: attached to an ancestor element. In this case, the attribute name is given
! 3325: instead of a constant value.</P>
! 3326: <P>
! 3327: It is also possible to write rules which apply only when a comparison between
! 3328: two different attributes of the element's ancestors is true. In this case, the
! 3329: first attribute name is followed by a comparison keyword and the name of the
! 3330: second attribute. The comparison keywords are <TT>EQUAL</TT> (simple
! 3331: equality), <TT>LESS</TT> (non-inclusive less than), and <TT>GREATER</TT>
! 3332: (non-inclusive greater than).</P>
! 3333: </DD>
! 3334: <DT>text attribute</DT>
! 3335: <DD>If the rules are to apply for one value ofthe attribute, then the
! 3336: attribute name is followed by an equals signand this value.
! 3337: </DD>
! 3338: <DT>reference attribute</DT>
! 3339: <DD>There is never a value specification; therules apply no matter what
! 3340: element is designated by the attribute.
! 3341: </DD>
! 3342: <DT>enumerated attribute</DT>
! 3343: <DD>If the rules are to apply for one value ofthe attribute, then the
! 3344: attribute name is followed by an equals signand this value.
! 3345: </DD>
! 3346: </DL>
! 3347: <P>
! 3348: The order in which the rules associated with a numeric attribute are defined
! 3349: is important. When multiple sets of rules can be applied, the first set
! 3350: declared is the one used.</P>
! 3351: <P>
! 3352: Rules for attributes have priority over both default rules and rules
! 3353: associated with element types. The attribute rules apply to the element to
! 3354: which the attribute is attached. It is the rules which apply to the
! 3355: surrounding elements (and especially to the descendants) which determine the
! 3356: effect of the attribute rules on the environment ( and especially on the
! 3357: terminal elements of the structure).</P>
! 3358: <PRE>
! 3359: 'ATTRIBUTES' PresAttrSeq
! 3360: PresAttrSeq = PresAttr < PresAttr > .
! 3361: PresAttr = AttrID [ '(' [ FirstSec ] ElemID ')' ]
! 3362: [ AttrRelation ] ':' ViewRuleSeq .
! 3363: AttrID = NAME .
! 3364: AttrRelation ='=' AttrVal /
! 3365: '>' [ '-' ] MinValue /
! 3366: '<' [ '-' ] MaxValue /
! 3367: 'IN' '[' [ '-' ] LowerBound '..'
! 3368: [ '-' ] UpperBound ']' /
! 3369: 'GREATER' AttrID /
! 3370: 'EQUAL' AttrID /
! 3371: 'LESS' AttrID .
! 3372: AttrVal = [ '-' ] EqualNum / EqualText /
! 3373: AttrValue .
! 3374: MinValue = NUMBER .
! 3375: MaxValue = NUMBER .
! 3376: LowerBound = NUMBER .
! 3377: UpperBound = NUMBER.
! 3378: EqualNum = NUMBER .
! 3379: EqualText = STRING .
! 3380: AttrValue = NAME .
! 3381: </PRE>
! 3382: <P>
! 3383: In presentation rules associated with a numeric attribute (and only in such
! 3384: rules), the attribute name can be used in place of a numeric value. In this
! 3385: case, the value of the attribute is used in the application of the rule. Thus,
! 3386: the attribute can represent a relation between the size of two boxes, the
! 3387: height and width of a box, the height of an area where page breaks are
! 3388: prohibited, the distance between two boxes, the position of the reference axis
! 3389: of a box, the interline spacing, the indentation of the first line, the
! 3390: visibility, the depth (z-order), or the character set.</P>
! 3391: <P>
! 3392: The presentation rules associated with reference attributes, it is possible to
! 3393: use the element designated by the attribute as a reference box in a positional
! 3394: or extent rule. This element is represented in the <A
! 3395: href="#position">position</A> or <A href="#dimension">extent</A> rule by the
! 3396: keyword <TT>Referred</TT>.</P>
! 3397: <BLOCKQUOTE class="example">
! 3398: <P>
! 3399: <STRONG>Example:</STRONG></P>
! 3400: <P>
! 3401: In all structure schemas, there is a global Language attributedefined as
! 3402: follows:</P>
! 3403: <PRE>
! 3404: ATTR
! 3405: Language = TEXT;
! 3406: </PRE>
! 3407: <P>
! 3408: The following rules would make French text be displayed in romancharacters and
! 3409: English text be displayed in italics:</P>
! 3410: <PRE>
! 3411: ATTRIBUTES
! 3412: Language = 'French' :
! 3413: Style : Roman;
! 3414: Language = 'English' :
! 3415: Style : Italics;
! 3416: </PRE>
! 3417: <P>
! 3418: Using these rules, when the user puts the Language attribute with thevalue
! 3419: 'English' on the summary of a document, every character string(terminal
! 3420: elements) contained in the summary are displayed in italics.See the <A
! 3421: href="#style"><TT>Style</TT> rule</A>.</P>
! 3422: </BLOCKQUOTE>
! 3423: <BLOCKQUOTE class="example">
! 3424: <P>
! 3425: <STRONG>Example:</STRONG></P>
! 3426: <P>
! 3427: A numeric attribute representing the importance of the part of thedocument to
! 3428: which it is attached can be defined:</P>
! 3429: <PRE>
! 3430: ATTR
! 3431: Importance = INTEGER;
! 3432: </PRE>
! 3433: <P>
! 3434: In the presentation schema, the importance of an element is reflectedin the
! 3435: choice of character size, using the following rules.</P>
! 3436: <PRE>
! 3437: ATTRIBUTES
! 3438: Importance < 2 :
! 3439: Size : 1;
! 3440: Importance IN [2..4] :
! 3441: Size : Importance;
! 3442: Importance = 10 :
! 3443: Size : 5;
! 3444: Importance > 4 :
! 3445: Size : 4;
! 3446: </PRE>
! 3447: <P>
! 3448: Thus, the character size corresponds to the value of the Importanceattribute;
! 3449: its value is</P>
! 3450: <UL>
! 3451: <LI>the value of the Importance attribute when the value isbetween 2 and 4
! 3452: (inclusive),
! 3453: <LI>1, when the value of the Importance attribute is less than 2,
! 3454: <LI>4, when the value of the Importance attribute is greater than4,
! 3455: <LI>5, when the value of the Importance attribute is 10.
! 3456: </UL>
! 3457: <P>
! 3458: The last case (value 5) must be defined before the case which handlesall
! 3459: Importance values greater than 4, because the two rules are notdisjoint and
! 3460: the first one defined will have priority. Otherwise,when the Importance
! 3461: attribute has value 10, the font size will be 4.</P>
! 3462: </BLOCKQUOTE>
! 3463: <BLOCKQUOTE class="example">
! 3464: <P>
! 3465: <STRONG>Example:</STRONG></P>
! 3466: <P>
! 3467: Suppose the structure defines a list element which can have anattribute
! 3468: defining the type of list (numbered or not):</P>
! 3469: <PRE>
! 3470: STRUCT
! 3471: list (ATTR list_type = enumeration, dash)
! 3472: = LIST OF (list_item = TEXT);
! 3473: </PRE>
! 3474: <P>
! 3475: Then, the presentation schema could use the attribute placed on thelist
! 3476: element to put either a dash or a number before the each elementof the
! 3477: list:</P>
! 3478: <PRE>
! 3479: ATTRIBUTES
! 3480: list_type (list_item) = enumeration :
! 3481: CreateBefore (NumberBox);
! 3482: list_type (list_item) = dash :
! 3483: CreateBefore (DashBox);
! 3484: </PRE>
! 3485: </BLOCKQUOTE>
! 3486: <BLOCKQUOTE class="example">
! 3487: <P>
! 3488: <STRONG>Example:</STRONG></P>
! 3489: <P>
! 3490: Suppose that two attributes are defined in the structure schema. Thefirst is
! 3491: a numeric global attribute called ``version''. The other isa local attribute
! 3492: defined on the root of the document called``Document_version'':</P>
! 3493: <PRE>
! 3494: STRUCTURE Document
! 3495: ATTR
! 3496: version = INTEGER;
! 3497: STRUCT
! 3498: Document (ATTR Document_version = INTEGER) =
! 3499: BEGIN
! 3500: SomeElement ;
! 3501: ...
! 3502: SomeOtherElement ;
! 3503: END ;
! 3504: ...
! 3505: </PRE>
! 3506: <P>
! 3507: These attributes can be used in the presentation schema to placechange bars in
! 3508: the margin next to elements whose version attributehas a value equal to the
! 3509: Document_version attribute of the root andto place a star in margin of
! 3510: elements whose version attribute is lessthan the value of the root's
! 3511: Document_version attribute:</P>
! 3512: <PRE>
! 3513: ATTRIBUTES
! 3514: version EQUAL Document_version :
! 3515: CreateBefore (ChangeBarBox) ;
! 3516: version LESS Document_version :
! 3517: CreateBefore (StarBox) ;
! 3518: </PRE>
! 3519: </BLOCKQUOTE>
! 3520: </DIV>
! 3521:
! 3522: <DIV class="subsection">
! 3523: <H3>Value transmission rules</H3>
! 3524:
! 3525: <P>
! 3526: The last section of a presentation schema, which is optional, serves to
! 3527: defines the way in which a document transmits certain values to its
! 3528: sub-documents. A sub-document is an document <A
! 3529: href="#inclusion">included</A> without expansion or with partial expansion.
! 3530: The primary document can transmit to its sub-documents the values of certain
! 3531: counters or the textual content of certain of its elements, as a function of
! 3532: their type.</P>
! 3533: <P>
! 3534: The sub-documents receive these values in attributes which must be defined in
! 3535: their structure schema as local attributes of the root element. The types of
! 3536: these attributes must correspond to the type of the value which they receive:
! 3537: numeric attributes for receiving the value of a counter, textual attributes
! 3538: for receiving the content of an element.</P>
! 3539: <P>
! 3540: In the structure schema of the primary document, there appears at the end,
! 3541: after the <TT>TRANSMIT</TT> keyword, a sequence of transmission rules. Each
! 3542: rule begins with the name of the counter to transmit or of the element type
! 3543: whose textual content will be transmitted. This name is followed by the
! 3544: keyword <TT>To</TT> and the name of the attribute of the sub-document to which
! 3545: the value is transmitted. The sub-document class is indicated between
! 3546: parentheses after the name of the attribute. The transmission rule ends with
! 3547: a semicolon.</P>
! 3548: <PRE>
! 3549: TransmitSeq = Transmit < Transmit > .
! 3550: Transmit = TypeOrCounter 'To' ExternAttr
! 3551: '(' ElemID ')' ';' .
! 3552: TypeOrCounter = CounterID / ElemID .
! 3553: ExternAttr = NAME .
! 3554: </PRE>
! 3555: <BLOCKQUOTE class="example">
! 3556: <P>
! 3557: <STRONG>Example:</STRONG></P>
! 3558: <P>
! 3559: Consider a Book document class which includes instances of the Chapterdocument
! 3560: class. These classes might have the following schemas:</P>
! 3561: <PRE>
! 3562: STRUCTURE Book
! 3563: STRUCT
! 3564: Book = BEGIN
! 3565: Title = Text;
! 3566: Body = LIST OF (Chapter INCLUDED);
! 3567: END;
! 3568: ...
! 3569:
! 3570: STRUCTURE Chapter
! 3571: STRUCT
! 3572: Chapter (ATTR FirstPageNum = Integer;
! 3573: ChapterNum = Integer;
! 3574: CurrentTitle = Text) =
! 3575: BEGIN
! 3576: ChapterTitle = Text;
! 3577: ...
! 3578: END;
! 3579: ...
! 3580: </PRE>
! 3581: <P>
! 3582: Then the presentation schema for books could define chapter and page counters.
! 3583: The following transmission rules in the book presentation schema would
! 3584: transmit values for the three attributes defined at the root of each chapter
! 3585: sub-document.</P>
! 3586: <PRE>
! 3587: PRESENTATION Book;
! 3588: VIEWS
! 3589: Full_text;
! 3590: COUNTERS
! 3591: ChapterCtr: Rank of Chapter;
! 3592: PageCtr: Rank of Page(Full_text);
! 3593: ...
! 3594: TRANSMIT
! 3595: PageCtr TO FirstPageNum(Chapter);
! 3596: ChapterCtr TO ChapterNum(Chapter);
! 3597: Title TO CurrentTitle(Chapter);
! 3598: END
! 3599: </PRE>
! 3600: <P>
! 3601: Thus, each chapter included in a book can number its pages as a function of
! 3602: the number of pages preceding it in the book, can make the chapter's number
! 3603: appear before the number of each of its sections, or can place the title of
! 3604: the book at the top of each page.</P>
! 3605: </BLOCKQUOTE>
! 3606: </DIV>
! 3607:
! 3608: <DIV class="subsection">
! 3609: <H3>Presentation rules</H3>
! 3610:
! 3611: <P>
! 3612: Whether defining the appearance of a presentation or page layout box, an
! 3613: element type, or an attribute value, the set of presentation rules that apply
! 3614: is always defined in the same way.</P>
! 3615: <P>
! 3616: Normally, a set of presentation rules is placed between the keywords
! 3617: <TT>BEGIN</TT> and <TT>END</TT>, the keyword <TT>END</TT> being followed by a
! 3618: semicolon. The first section of this block defines the rules that apply to
! 3619: the primary view, if the <A href="#defaultpresrules">default rules</A> are not
! 3620: completely suitable. Next comes the rules which apply to specific other
! 3621: views, with a rule sequence for each view for which the default rules are not
! 3622: satisfactory. If the default rules are suitable for the non-primary views,
! 3623: there will not be any specific rules for these views. If there is only one
! 3624: rule which applies to all views then the keywords <TT>BEGIN</TT> and
! 3625: <TT>END</TT> need not appear.</P>
! 3626: <P>
! 3627: For each view, it is only necessary to specify those rules which differ from
! 3628: the default rules for the view, so that for certain views (or even all views),
! 3629: there may be no specific rules.</P>
! 3630: <P>
! 3631: The specific rules for a non-primary view are introduced by the <A
! 3632: name="inkeyword"><TT>IN</TT> keyword</A>, followed by the view name. The
! 3633: rules for that view follow, delimited by the keywords <TT>BEGIN</TT> and
! 3634: <TT>END</TT>, or without these two keywords when there is only one rule.</P>
! 3635: <P>
! 3636: <STRONG>Note:</STRONG> the view name which follows the <TT>IN</TT> keyword
! 3637: must not be the name of the primary view, since the rules for that view are
! 3638: found before the rules for the other views.</P>
! 3639: <P>
! 3640: Within each block concerning a view, other blocks can appear, delimited by the
! 3641: same keywords <TT>BEGIN</TT> and <TT>END</TT>. Each of these blocks gathers
! 3642: the presentation rules that apply, for a given view, only when a given
! 3643: condition is satisfied. Each block is preceded by a condition introduced by
! 3644: the <TT>IF</TT> keyword. If such a conditional block contains only one rule,
! 3645: the keywords <TT>BEGIN</TT> and <TT>END</TT> can be omitted.</P>
! 3646: <P>
! 3647: Although the syntax allows any presentation rule to appear in a conditional
! 3648: block, only <A href="#creation">creation rules</A> are allowed after any
! 3649: condition; other rules are allowed only after conditions <TT>Within</TT> and
! 3650: ElemID. In addition, the following rules cannot be conditional:
! 3651: <TT>PageBreak, LineBreak, Inline, Gather</TT>.</P>
! 3652: <P>
! 3653: For a given view, the rules that apply without any condition must appear
! 3654: before the first conditional block. If some rules apply only when none of the
! 3655: specified condition holds, they are grouped in a block preceded by the keyword
! 3656: <TT>Otherwise</TT>, and that block must appear after the last conditionnal
! 3657: block concerning the same view.</P>
! 3658: <PRE>
! 3659: ViewRuleSeq = 'BEGIN' < RulesAndCond > < ViewRules >
! 3660: 'END' ';' /
! 3661: ViewRules / CondRules / Rule .
! 3662: RulesAndCond = CondRules / Rule .
! 3663: ViewRules = 'IN' ViewID CondRuleSeq .
! 3664: CondRuleSeq = 'BEGIN' < RulesAndCond > 'END' ';' /
! 3665: CondRules / Rule .
! 3666: CondRules = CondRule < CondRule >
! 3667: [ 'Otherwise' RuleSeq ] .
! 3668: CondRule = 'IF' ConditionSeq RuleSeq .
! 3669: RulesSeq = 'BEGIN' Rule < Rule > 'END' ';' /
! 3670: Rule .
! 3671: </PRE>
! 3672: <BLOCKQUOTE class="example">
! 3673: <P>
! 3674: <STRONG>Example:</STRONG></P>
! 3675: <P>
! 3676: The following rules for a report's title make the title visible in theprimary
! 3677: view and invisible in the table of contents and in the formulaviews (see the
! 3678: <A href="#visib"><TT>Visibility</TT> rule</A>).</P>
! 3679: <PRE>
! 3680: Title : BEGIN
! 3681: Visibility : 1;
! 3682: ... {Other rules for the primary view}
! 3683: IN Table_of_contents
! 3684: Visibility : 0;
! 3685: IN Formulas
! 3686: Visibility : 0;
! 3687: END;
! 3688: </PRE>
! 3689: </BLOCKQUOTE>
! 3690: </DIV>
! 3691:
! 3692: <DIV class="subsection">
! 3693: <H3>Conditions applying to presentation rules</H3>
! 3694:
! 3695: <P>
! 3696: Many conditions can be applied to presentation rules. Conditions allow
! 3697: certain presentation rules to apply only in certain cases. These conditions
! 3698: can be based on the structural position of the element. They can be based on
! 3699: whether the element has references, and what type of references, whether the
! 3700: element has attributes, whether the element is empty or not. They can also be
! 3701: based on the value of a counter.</P>
! 3702: <P>
! 3703: It is possible to specify several conditions which must all be true for the
! 3704: rules to apply.</P>
! 3705: <P>
! 3706: A set of conditions is specified by the <TT>IF</TT> keyword. This keyword is
! 3707: followed by the sequence of conditions, separated by the <TT>AND</TT> keyword.
! 3708: Each condition is specified by a keyword which defines the condition type. In
! 3709: some cases, the keyword is followed by other data, which specify the condition
! 3710: more precisely.</P>
! 3711: <P>
! 3712: An elementary condition can be negative; it is then preceded by the
! 3713: <TT>NOT</TT> keyword.</P>
! 3714: <P>
! 3715: When the presentation rule(s) controlled by the condition apply to a reference
! 3716: element or a reference attribute, an elementary condition can also apply to
! 3717: element referred by this reference. The <TT>Target</TT> keyword is used for
! 3718: that purpose. It must appear before the keyword defining the condition
! 3719: type.</P>
! 3720: <PRE>
! 3721: CondRule = 'IF' ConditionSeq RuleSeq .
! 3722: ConditionSeq = Condition < 'AND' Condition > .
! 3723: Condition = [ 'NOT' ] [ 'Target' ] ConditionElem .
! 3724: ConditionElem ='First' / 'Last' /
! 3725: [ 'Immediately' ] 'Within' [ NumParent ]
! 3726: ElemID [ ExtStruct ] /
! 3727: ElemID /
! 3728: 'Referred' / 'FirstRef' / 'LastRef' /
! 3729: 'ExternalRef' / 'InternalRef' / 'CopyRef' /
! 3730: 'AnyAttributes' / 'FirstAttr' / 'LastAttr' /
! 3731: 'UserPage' / 'StartPage' / 'ComputedPage' /
! 3732: 'Empty' /
! 3733: '(' [ MinMax ] CounterName CounterCond ')' /
! 3734: CondPage '(' CounterID ')' .
! 3735: NumParent = [ GreaterLess ] NParent .
! 3736: GreaterLess = '>' / '<' .
! 3737: NParent = NUMBER.
! 3738: ExtStruct = '(' ElemID ')' .
! 3739: CounterCond ='<' MaxCtrVal / '>' MinCtrVal /
! 3740: '=' EqCtrVal /
! 3741: 'IN' '[' ['-'] MinCtrBound '.' '.'
! 3742: ['-'] MaxCtrBound ']' .
! 3743: PageCond ='Even' / 'Odd' / 'One' .
! 3744: MaxCtrVal = NUMBER .
! 3745: MinCtrVal = NUMBER .
! 3746: EqCtrVal = NUMBER .
! 3747: MaxCtrBound = NUMBER .
! 3748: MinCtrBound = NUMBER .
! 3749: </PRE>
! 3750:
! 3751: <DIV class="subsubsection">
! 3752: <H4>Conditions based on the logical position of the element</H4>
! 3753:
! 3754: <P>
! 3755: The condition can be on the position of the element in the document's logical
! 3756: structure tree. It is possible to test whether the element is the first
! 3757: (<TT>First</TT>) or last (<TT>Last</TT>) among its siblings or if it is not
! 3758: the first (<TT>NOT First</TT>) or not the last (<TT>NOT Last</TT>). These
! 3759: conditions can be associated only with <A href="#creation">creation
! 3760: rules</A>.</P>
! 3761: <P>
! 3762: It is also possible to test if the element is contained in an element of a
! 3763: given type (<TT>Within</TT>) or if it is not (<TT>NOT Within</TT>). The type
! 3764: is indicated after the keyword <TT>Within</TT>. If that element type is
! 3765: defined in a structure schema which is not the one which corresponds to the
! 3766: presentation schema, the type name of this element must be followed, between
! 3767: parentheses, by the name of the structure schema which defines it.</P>
! 3768: <P>
! 3769: If the keyword <TT>Within</TT> is preceded by <TT>Immediately</TT>, the
! 3770: condition is satisfied only if the <EM>parent</EM> element has the type
! 3771: indicated. If the word <TT>Immediately</TT> is missing, the condition is
! 3772: satisfied if any <EM>ancestor</EM> has the type indicated.</P>
! 3773: <P>
! 3774: An integer <I>n</I> can appear between the keyword <TT>Within</TT> and the
! 3775: type. It specifies the number of ancestors of the indicated type that must be
! 3776: present for the condition to be satisfied. If the keyword
! 3777: <TT>Immediately</TT> is also present, the <I>n</I> immediate ancestors of the
! 3778: element must have the indicated type. The integer <I>n</I> must be positive
! 3779: or zero. It can be preceded by <TT><</TT> or <TT>></TT> to indicate a
! 3780: maximum or minimum number of ancestors. If these symbols are missing, the
! 3781: condition is satisfied only if it exists exactly <I>n</I> ancestors. When
! 3782: this number is missing, it is equivalent to > 0.</P>
! 3783: <P>
! 3784: If the condition applies to presentation rules associated with an attribute,
! 3785: in the <TT>ATTRIBUTES</TT> section of the presentation schema, the condition
! 3786: can be simply an element name. Presentation rules are then executed only if
! 3787: the attribute is attached to an element of that type. The keyword <TT>NOT</TT>
! 3788: before the element name indicates that the presentation rules must be executed
! 3789: only if the element is not of the type indicated.</P>
! 3790: </DIV>
! 3791:
! 3792: <DIV class="subsubsection">
! 3793: <H4>Conditions on references</H4>
! 3794:
! 3795: <P>
! 3796: References may be taken into account in conditions, which can be based on the
! 3797: fact that the element, or one of its ancestors, is designated by a at least
! 3798: one reference (<TT>Referred</TT>) or by none (<TT>NOT Referred</TT>).</P>
! 3799: <P>
! 3800: If the element or attribute to which the condition is attached is a reference,
! 3801: the condition can be based on the fact that it acts as the first reference to
! 3802: the designated element (<TT>FirstRef</TT>), or as the last (<TT>LastRef</TT>),
! 3803: or as a reference to an element located in another document
! 3804: (<TT>ExternalRef</TT>) or in the same document (<TT>InternalRef</TT>).</P>
! 3805: <P>
! 3806: The condition can also be based on the fact that the element is an <A
! 3807: href="#inclusion">inclusion</A>. This is noted (<TT>CopyRef</TT>).</P>
! 3808: <P>
! 3809: Like all conditions, conditions on references can be inverted by the
! 3810: <TT>NOT</TT> keyword. These conditions can be associated only with <A
! 3811: href="#creation">creation rules</A>.</P>
! 3812: </DIV>
! 3813:
! 3814: <DIV class="subsubsection">
! 3815: <H4>Conditions on logical attributes</H4>
! 3816:
! 3817: <P>
! 3818: The condition can be based on the presence or absence of attributes associated
! 3819: with the element, no matter what the attributes or their values. The
! 3820: <TT>AnyAttributes</TT> keyword expresses this condition.</P>
! 3821: <P>
! 3822: If the condition appears in the presentation rules of an attribute, the
! 3823: <TT>FirstAttr</TT> and <TT>LastAttr</TT> keywords can be used to indicate that
! 3824: the rules must only be applied if this attribute is the first attribute for
! 3825: the element or if it is the last (respectively). These conditions can also be
! 3826: inverted by the <TT>NOT</TT> keyword. These conditions can be associated only
! 3827: with <A href="#creation">creation rules</A>.</P>
! 3828: <P>
! 3829: It is also possible to apply certain presentation rules only when the element
! 3830: being processed or one of its ancestors has a certain attribute, perhaps with
! 3831: a certain value. This can be done in the <A
! 3832: href="#presattributes"><TT>ATTRIBUTES</TT> section</A>.</P>
! 3833: </DIV>
! 3834:
! 3835: <DIV class="subsubsection">
! 3836: <H4>Conditions on page breaks</H4>
! 3837:
! 3838: <P>
! 3839: The page break base type (and only this type) can use the following
! 3840: conditions: <TT>ComputedPage</TT>, <TT>StartPage</TT>, and <TT>UserPage</TT>.
! 3841: The <TT>ComputedPage</TT> condition indicates that the presentation rule(s)
! 3842: should apply if the page break was created automatically by Thot; the
! 3843: <TT>StartPage</TT> condition is true if the page break is generated before the
! 3844: element by the <TT>Page</TT> rule; and the <TT>UserPage</TT> condition applies
! 3845: if the page break was inserted by the user.</P>
! 3846: <P>
! 3847: These conditions can be associated only with <A href="#creation">creation
! 3848: rules</A>.</P>
! 3849: </DIV>
! 3850:
! 3851: <DIV class="subsubsection">
! 3852: <H4>Conditions on the element's content</H4>
! 3853:
! 3854: <P>
! 3855: The condition can be based on whether or not the element is empty. An element
! 3856: which has no children or whose leaves are all empty is considered to be empty
! 3857: itself. This condition is expressed by the <TT>Empty</TT> keyword, optionally
! 3858: preceded by the <TT>NOT</TT> keyword. This condition can be associated only
! 3859: with <A href="#creation">creation rules</A>.</P>
! 3860: </DIV>
! 3861:
! 3862: <DIV class="subsubsection">
! 3863: <H4>Conditions on counters</H4>
! 3864:
! 3865: <P>
! 3866: Presentation rules can apply when the counter's value is one, is even or odd,
! 3867: is equal, greater than or less than a given value or falls in a range of
! 3868: values. This is particularly useful for creating header and footer boxes.
! 3869: These conditions can be associated only with <A href="#creation">creation
! 3870: rules</A>.</P>
! 3871: <P>
! 3872: To compare the value of a counter to a given value, a comparison is given
! 3873: between parentheses. The comparison is composed of the counter name followed
! 3874: by an equals, greater than, or less than sign and the value to which the
! 3875: counter will be compared. A test for whether or not a counter's value falls
! 3876: in a range also appears within parentheses. In this case, the counter name is
! 3877: followed by the <TT>IN</TT> keyword and the range definition within brackets.
! 3878: The <TT>Even</TT>, <TT>Odd</TT> and <TT>One</TT> are used to test a counter's
! 3879: value and are followed by the counter name between parentheses.</P>
! 3880: <P>
! 3881: The list of possible conditions on counters is:</P>
! 3882: <DL>
! 3883: <DT><TT>Even (Counter)</TT></DT>
! 3884: <DD>the box is created only if the counterhas an even value.
! 3885: </DD>
! 3886: <DT><TT>Odd (Counter)</TT></DT>
! 3887: <DD>the box is created only if the counterhas an odd value.
! 3888: </DD>
! 3889: <DT><TT>One (Counter)</TT></DT>
! 3890: <DD>the box is created only the counter'svalue is 1.
! 3891: </DD>
! 3892: <DT><TT>NOT One (Counter)</TT></DT>
! 3893: <DD>the box is created, unless thecounter's value is 1.
! 3894: </DD>
! 3895: <DT><TT>(Counter < Value)</TT></DT>
! 3896: <DD>the box is created only if thecounter's value is less than Value.
! 3897: </DD>
! 3898: <DT><TT>(Counter > Value)</TT></DT>
! 3899: <DD>the box is created only if thecounter's value is greater than Value.
! 3900: </DD>
! 3901: <DT><TT>(Counter = Value)</TT></DT>
! 3902: <DD>the box is created only if thecounter's value is equal to Value.
! 3903: </DD>
! 3904: <DT><TT>NOT (Counter = Value)</TT></DT>
! 3905: <DD>the is created only if thecounter's value is different than Value.
! 3906: </DD>
! 3907: <DT><TT>(Counter IN [MinValue..MaxValue])</TT></DT>
! 3908: <DD>the box is createdonly if the counter's value falls in the range bounded
! 3909: by MinValue andMaxValue (inclusive).
! 3910: </DD>
! 3911: <DT><TT>NOT (Counter IN [MinValue..MaxValue])</TT></DT>
! 3912: <DD>the box iscreated only if the value of the counter does not fall in the
! 3913: range boundedby MinValue and MaxValue (inclusive).
! 3914: </DD>
! 3915: </DL>
! 3916: <P>
! 3917: <STRONG>Note:</STRONG> the <TT>NOT Even</TT> and <TT>NOT Odd</TT> conditions
! 3918: are syntactically correct but can be expressed more simply by <TT>Odd</TT> and
! 3919: <TT>Even</TT>, respectively.</P>
! 3920: </DIV>
! 3921: </DIV>
! 3922:
! 3923: <DIV class="subsection">
! 3924: <H3><A name="presrule">A presentation rule</A></H3>
! 3925:
! 3926: <P>
! 3927: A presentation rule defines either a presentation parameter or presentation
! 3928: function. The parameters are:</P>
! 3929: <UL>
! 3930: <LI>the position of the vertical and horizontal reference axes ofthe box,
! 3931: <LI>the position of the box in relation to other boxes,
! 3932: <LI>the height or width of the box, with overflow exceptions,
! 3933: <LI>the characteristics of the lines contained in the box: interlinespacing,
! 3934: indentation of the first line, justification, hyphenation,
! 3935: <LI>the conditions for breaking the box across pages,
! 3936: <LI>the characteristics of the characters contained in the box:size, font,
! 3937: style, underlining,
! 3938: <LI>the depth of the box among overlapping boxes (often calledstacking order),
! 3939: <LI>the characteristics of graphic elements contained in the box:style and
! 3940: thickness of lines, fill pattern for closed objects,
! 3941: <LI>the colors in text, graphics, images, and symbols contained inthe box are
! 3942: displayed or printed,
! 3943: <LI>for presentation boxes only, the contents of the box.
! 3944: </UL>
! 3945: <P>
! 3946: The <A name="presfunct">presentation functions</A>are:</P>
! 3947: <UL>
! 3948: <LI>the creation of a presentation box
! 3949: <LI>the line-breaking or page-breaking style,
! 3950: <LI>the copying of another box.
! 3951: </UL>
! 3952: <P>
! 3953: For each box and each view, every presentation parameter is defined once and
! 3954: only once, either explicitly or by the <A href="#defaultpresrules">default
! 3955: rules</A>. In contrast, presentation functions are not obligatory and can
! 3956: appear many times for the same element. for example an element can create
! 3957: many presentation boxes. Another element may not use any presentation
! 3958: functions.</P>
! 3959: <P>
! 3960: Each rule defining a presentation parameter begins with a keyword followed by
! 3961: a colon. the keyword indicates the parameter which is the subject of the rule.
! 3962: After the keyword and the colon, the remainder of the rule varies. All rules
! 3963: are terminated by a semicolon.</P>
! 3964: <PRE>
! 3965: Rule = PresParam ';' / PresFunc ';' .
! 3966: PresParam ='VertRef' ':' PositionHoriz /
! 3967: 'HorizRef' ':' PositionVert /
! 3968: 'VertPos' ':' VPos /
! 3969: 'HorizPos' ':' HPos /
! 3970: 'Height' ':' Dimension /
! 3971: 'Width' ':' Dimension /
! 3972: 'VertOverflow' ':' Boolean /
! 3973: 'HorizOverflow' ':' Boolean /
! 3974: 'LineSpacing' ':' DistanceInherit /
! 3975: 'Indent' ':' DistanceInherit /
! 3976: 'Adjust' ':' AdjustInherit /
! 3977: 'Justify' ':' BoolInherit /
! 3978: 'Hyphenate' ':' BoolInherit /
! 3979: 'PageBreak' ':' Boolean /
! 3980: 'LineBreak' ':' Boolean /
! 3981: 'InLine' ':' Boolean /
! 3982: 'NoBreak1' ':' AbsDist /
! 3983: 'NoBreak2' ':' AbsDist /
! 3984: 'Gather' ':' Boolean /
! 3985: 'Visibility' ':' NumberInherit /
! 3986: 'Size' ':' SizeInherit /
! 3987: 'Font' ':' NameInherit /
! 3988: 'Style' ':' StyleInherit /
! 3989: 'Underline' ':' UnderLineInherit /
! 3990: 'Thickness' ':' ThicknessInherit /
! 3991: 'Depth' ':' NumberInherit /
! 3992: 'LineStyle' ':' LineStyleInherit /
! 3993: 'LineWeight' ':' DistanceInherit /
! 3994: 'FillPattern' ':' NameInherit /
! 3995: 'Background' ':' NameInherit /
! 3996: 'Foreground' ':' NameInherit .
! 3997: 'Content' ':' VarConst .
! 3998: PresFunc = Creation '(' BoxID ')' /
! 3999: 'Line' /
! 4000: 'NoLine' /
! 4001: 'Page' '(' BoxID ')' /
! 4002: 'Copy' '(' BoxTypeToCopy ')' .
! 4003: </PRE>
! 4004: </DIV>
! 4005:
! 4006: <DIV class="subsection">
! 4007: <H3>Box axes</H3>
! 4008:
! 4009: <P>
! 4010: The position of the middle axes <TT>VMiddle</TT> and <TT>HMiddle</TT> in
! 4011: relation to their box is always calculated automatically as a function of the
! 4012: height and width of the box and is not specified by the presentation rules. In
! 4013: the presentation schema, these middle axes are used only to position their box
! 4014: with respect to another by specifying the distance between the middle axis and
! 4015: an axis or a side of another box (see the <A href="#position">relative
! 4016: position</A>).</P>
! 4017: <P>
! 4018: The reference axes of a box are also used to position their box in relation to
! 4019: another, but in contrast to the middle axes, the presentation schema must make
! 4020: their position explicit, either in relation to a side or the middle axis of
! 4021: the box itself, or in relation to an axis of an enclosed box.</P>
! 4022: <P>
! 4023: Only boxes of base elements have predefined reference axes. For character
! 4024: string boxes, the horizontal reference axis is the baseline of the characters
! 4025: (the line which passes immediately under the upper-case letters, ignoring the
! 4026: letter Q) and the vertical reference axis is at the left edge of the first
! 4027: character of the string.</P>
! 4028: <P>
! 4029: The positions of a box's reference axes are defined by the <TT>VertRef</TT>
! 4030: and <TT>HorizRef</TT> rules which specify the <A href="#distance">distance</A>
! 4031: between the reference axis and an axis or parallel side of the same box or of
! 4032: an enclosed box.</P>
! 4033: <PRE>
! 4034: 'VertRef' ':' PositionHoriz
! 4035: 'HorizRef' ':' PositionVert
! 4036: </PRE>
! 4037: <BLOCKQUOTE class="example">
! 4038: <P>
! 4039: <STRONG>Example:</STRONG></P>
! 4040: <P>
! 4041: If, in the structure schema for mathematical formulas, the fractionelement is
! 4042: defined by</P>
! 4043: <PRE>
! 4044: Fraction = BEGIN
! 4045: Numerator = Expression;
! 4046: Denominator = Expression;
! 4047: END;
! 4048: </PRE>
! 4049: <P>
! 4050: then the horizontal reference axis of the fraction can be positionedon top of
! 4051: the denominator by the rule:</P>
! 4052: <PRE>
! 4053: Fraction :
! 4054: BEGIN
! 4055: HorizRef : Enclosed Denominator . Top;
! 4056: ...
! 4057: END;
! 4058: </PRE>
! 4059: <P>
! 4060: To put the horizontal reference axis of a column at its middle:</P>
! 4061: <PRE>
! 4062: Column :
! 4063: BEGIN
! 4064: HorizRef : * . HMiddle;
! 4065: ...
! 4066: END;
! 4067: </PRE>
! 4068: </BLOCKQUOTE>
! 4069: </DIV>
! 4070:
! 4071: <DIV class="subsection">
! 4072: <H3><A name="distunits">Distance units</A></H3>
! 4073:
! 4074: <P>
! 4075: Some distances and dimensions appear in many rules of a presentation schema,
! 4076: especially in position rules (<TT>VertPos, HorizPos</TT>), in extent rules for
! 4077: boxes (<TT>Height, Width</TT>), in rules defining lines (<TT>LineSpacing,
! 4078: Indent</TT>), in rules controlling pagination (<TT>NoBreak1, NoBreak2</TT>)
! 4079: and in rules specifying the thickness of strokes (<TT>LineWeight</TT>).</P>
! 4080: <P>
! 4081: In all these rules, the distance or extent can be expressed</P>
! 4082: <UL>
! 4083: <LI>either in relative units, which depend on the size of thecharacters in the
! 4084: current font: height of the element's font orheight of the letter 'x',
! 4085: <LI>or in absolute units: centimeter, millimeter, inch, typographer'spoint,
! 4086: pica or pixel.
! 4087: </UL>
! 4088: <P>
! 4089: Units can be chosen freely. Thus, it is possible to use relative units inone
! 4090: rule, centimeters in the next rule, and typographer's points inanother.</P>
! 4091: <P>
! 4092: Absolute units are used to set rigid rules for the appearance of documents. In
! 4093: contrast, relative units allow changes of scale. The editor lets the value of
! 4094: relative units be changed dynamically. Such changes affect every box using
! 4095: relative units simultaneously and in the same proportion. Changing the value
! 4096: of the relative units affects the size of the characters and graphical
! 4097: elements, and the size of the boxes and the distances between them.</P>
! 4098: <P>
! 4099: A <A name="distance">distance</A> or extent is specified by a number, which
! 4100: may be followed by one or more spaces and a units keyword. When there is no
! 4101: units keyword, the number specifies the number of relative units, where a
! 4102: relative unit is the height of a character in the current font (an em). When
! 4103: the number is followed by a units keyword, the keyword indicates the type of
! 4104: absolute units:</P>
! 4105: <UL>
! 4106: <LI><TT>em</TT>: height of the element's font,
! 4107: <LI><TT>ex</TT>: height of the letter 'x',
! 4108: <LI><TT>cm</TT>: centimeter,
! 4109: <LI><TT>mm</TT>: millimeter,
! 4110: <LI><TT>in</TT>: inch (1 in = 2.54 cm),
! 4111: <LI><TT>pt</TT>: point (1 pt = 1/72 in),
! 4112: <LI><TT>pc</TT>: pica (1 pc = 12 pt),
! 4113: <LI><TT>px</TT>: pixel.
! 4114: </UL>
! 4115: <P>
! 4116: Whatever the chosen unit, relative or absolute, the number is not necessarily
! 4117: an integer and may be expressed in fixed point notation (using the American
! 4118: convention of a period to express the decimal point).</P>
! 4119: <P>
! 4120: If the distance appears in a presentation rule for a numeric attribute, the
! 4121: number can be replaced by the name of an attribute. In this case, the value
! 4122: of the attribute is used. Obviously, the attribute name cannot be followed by
! 4123: a decimal point and a fractional part, but it can be followed a units keyword.
! 4124: However, the choice of units is limited to em, ex, pt and px.</P>
! 4125: <PRE>
! 4126: Distance = [ Sign ] AbsDist .
! 4127: Sign ='+' / '-' .
! 4128: AbsDist = IntegerOrAttr [ '.' DecimalPart ]
! 4129: [ Unit ].
! 4130: IntegerOrAttr = IntegerPart / AttrID .
! 4131: IntegerPart = NUMBER .
! 4132: DecimalPart = NUMBER .
! 4133: Unit ='em' / 'ex' / 'cm' / 'mm' / 'in' / 'pt' /
! 4134: 'pc' / 'px' / '%' .
! 4135: </PRE>
! 4136: <BLOCKQUOTE class="example">
! 4137: <P>
! 4138: <STRONG>Example:</STRONG></P>
! 4139: <P>
! 4140: The following rules specify that a box has a height of 10.5centimeters and a
! 4141: width of 5.3 ems:</P>
! 4142: <PRE>
! 4143: Height : 10.5 cm;
! 4144: Width : 5.3;
! 4145: </PRE>
! 4146: </BLOCKQUOTE>
! 4147: </DIV>
! 4148:
! 4149: <DIV class="subsection">
! 4150: <H3><A name="position">Relative positions</A></H3>
! 4151:
! 4152: <P>
! 4153: The positioning of boxes uses the eight axes and sides, the sides generally
! 4154: being used to define the juxtapositioning (vertical or horizontal) of boxes,
! 4155: the middle axes being used to define centering, and the reference axes being
! 4156: used for alignment.</P>
! 4157: <P>
! 4158: Two rules allow a box to placed relative to other boxes. The <TT>VertPos</TT>
! 4159: rule positions the box vertically. The <TT>HorizPos</TT> rule positions the
! 4160: box horizontally. It is possible that a box's position could be entirely
! 4161: determined by other boxes positioned relative to it. In this case, the
! 4162: position is implicit and the word <TT>nil</TT> can be used to specify that no
! 4163: position rule is needed. Otherwise, an explicit rule must be given by
! 4164: indicating the axis or side which defines the position of the box, followed by
! 4165: an equals sign and the distance between between this axis or side and a
! 4166: parallel axis or side of another box, called the reference box. The box for
! 4167: which the rule is written will be positioned relative to the reference
! 4168: box.</P>
! 4169: <PRE>
! 4170: 'VertPos' ':' VPos
! 4171: 'HorizPos' ':' HPos
! 4172: HPos = 'nil' / VertAxis '=' HorizPosition
! 4173: [ 'UserSpecified' ].
! 4174: VPos = 'nil' / HorizAxis '=' VertPosition
! 4175: [ 'UserSpecified' ].
! 4176: VertAxis = 'Left' / 'VMiddle' / 'VRef' / 'Right' .
! 4177: HorizAxis = 'Top' / 'HMiddle' / 'HRef' / 'Bottom' .
! 4178: </PRE>
! 4179: <P>
! 4180: The reference box is an adjacent box: enclosing, enclosed or adjacent. When a
! 4181: rule is associated with a reference type attribute (and only in this case), it
! 4182: can be a box of the element designated by the attribute. The reference box
! 4183: can be either a presentation box previously defined in the <TT>BOXES</TT>
! 4184: section of the schema and created by a creation function, or the box
! 4185: associated with a structured element.</P>
! 4186: <P>
! 4187: The structural position of the reference box (relative to the box for which
! 4188: the rule is being written) is indicated by a keyword: <TT>Enclosing</TT>,
! 4189: <TT>Enclosed</TT>, or, for sibling boxes, <TT>Previous</TT> or <TT>Next</TT>.
! 4190: The reference attributes, or presentation boxes created by a reference
! 4191: attribute, the <TT>Referred</TT> keyword may be used to designate the element
! 4192: which the reference points to. The keyword <TT>Creator</TT> can be used in
! 4193: rules for presentation boxes to designate the box of the element which created
! 4194: the presentation box. Finally, the <TT>Root</TT> keyword can be used to
! 4195: designate the root of the document.</P>
! 4196: <P>
! 4197: When the keyword is ambiguous, it is followed by a name of a type or
! 4198: presentation box which resolves the ambiguity (the <TT>Creator</TT> and
! 4199: <TT>Root</TT> keywords are never ambiguous). If this name is not given, then
! 4200: the first box encountered is used as the reference box. It is also possible to
! 4201: use just the name of a type or presentation box without an initial keyword. In
! 4202: this case, a sibling having that name will be used. If the name is preceded
! 4203: by the keyword <TT>NOT</TT>, then the reference box will be the first box
! 4204: whose type is not the named one. In place of the box or type name, the
! 4205: keywords <TT>AnyElem</TT> and <TT>AnyBox</TT> can be used, representing
! 4206: respectively, any structured element box and any presentation box. A type
! 4207: name may be preceded by a star in order to resolve the ambiguity in the
! 4208: special case where the structure schema defines an <A
! 4209: href="#references">inclusion</A> without expansion (or with partial expansion)
! 4210: of the same type as an element of the scheme. For mark pairs (and only for <A
! 4211: href="#pairs">mark pairs</A>) the type name <EM>must</EM> be preceded by the
! 4212: <TT>First</TT> or <TT>Second</TT> keyword, which indicates which of the two
! 4213: marks of the pair should be used as the reference box.</P>
! 4214: <P>
! 4215: The star character ('<TT>*</TT>') used alone designates the box to which the
! 4216: rule applies (in this case, it is obviously useless to specify the type of the
! 4217: reference box).</P>
! 4218: <P>
! 4219: The keywords <TT>Enclosing</TT> and <TT>Enclosed</TT> can be used no matter
! 4220: what constructor defines the type to which the rule applies. When applied to
! 4221: the element which represents the entire document, <TT>Enclosing</TT>
! 4222: designates the window or page in which the document's image is displayed for
! 4223: the view to which the rule applies. A box or type name without a keyword is
! 4224: used for aggregate elements and designates another element of the same
! 4225: aggregate. It can also be used to designate a presentation or page layout
! 4226: box. The keywords <TT>Previous</TT> and <TT>Next</TT> are primarily used to
! 4227: denote list elements, but can also be used to denote elements of an
! 4228: aggregate.</P>
! 4229: <P>
! 4230: In the position rule, the structural position relative to the reference box is
! 4231: followed, after a period, by the name of an axis or side. The rule specifies
! 4232: its node's position as being some distance from this axis or side of the
! 4233: reference box. If this distance is zero, then the distance does not appear in
! 4234: the rule. Otherwise, it does appear as a positive or negative number (the
! 4235: sign is required for negative numbers). The sign takes into account the
! 4236: orientation of the coordinate axes: for top to bottom for the vertical axis
! 4237: and from left to right for the horizontal axis. Thus, a negative distance in
! 4238: a vertical position indicates that the side or axis specified in the rule is
! 4239: above the side or axis of the reference box.</P>
! 4240: <P>
! 4241: The distance can be followed by the <TT>UserSpecified</TT> keyword (even if
! 4242: the distance is nil and does not appear, the <TT>UserSpecified</TT> keyword
! 4243: can be used). It indicates that when the element to which the rule applies is
! 4244: being created, the editor will ask the user to specify the distance himself,
! 4245: using the mouse. In this case, the distance specified in the rule is a
! 4246: default distance which is suggested to the user but can be modified. The
! 4247: <TT>UserSpecified</TT> keyword can be used either in the vertical position
! 4248: rule, the horizontal position rule, or both.</P>
! 4249: <PRE>
! 4250: VertPosition = Reference '.' HorizAxis [ Distance ] .
! 4251: HorizPosition = Reference '.' VertAxis [ Distance ] .
! 4252: Reference ='Enclosing' [ BoxTypeNot ] /
! 4253: 'Enclosed' [ BoxTypeNot ] /
! 4254: 'Previous' [ BoxTypeNot ] /
! 4255: 'Next' [ BoxTypeNot ] /
! 4256: 'Referred' [ BoxTypeNot ] /
! 4257: 'Creator' /
! 4258: 'Root' /
! 4259: '*' /
! 4260: BoxOrType .
! 4261: BoxOrType = BoxID /
! 4262: [ '*' ] [ FirstSec ] ElemID /
! 4263: 'AnyElem' / 'AnyBox' .
! 4264: BoxTypeNot = [ 'NOT' ] BoxOrType .
! 4265: </PRE>
! 4266: <BLOCKQUOTE class="example">
! 4267: <P>
! 4268: <STRONG>Example:</STRONG></P>
! 4269: <P>
! 4270: If a <A name="expos1">report</A>is defined by by the following
! 4271: structureschema:</P>
! 4272: <PRE>
! 4273: Report = BEGIN
! 4274: Title = Text;
! 4275: Summary = Text;
! 4276: Keywords = Text;
! 4277: ...
! 4278: END;
! 4279: </PRE>
! 4280: <P>
! 4281: then the presentation schema could contain the rules:</P>
! 4282: <PRE>
! 4283: Report : BEGIN
! 4284: VertPos : Top = Enclosing . Top;
! 4285: HorizPos : Left = Enclosing . Left;
! 4286: ...
! 4287: END;
! 4288: </PRE>
! 4289: <P>
! 4290: These rules place the <A name="reportexample">report</A>in the upperleft
! 4291: corner of the enclosing box, which is the window in which thedocument is being
! 4292: edited.</P>
! 4293: <PRE>
! 4294: Title : BEGIN
! 4295: VertPos : Top = Enclosing . Top + 1;
! 4296: HorizPos : VMiddle = Enclosing . VMiddle;
! 4297: ...
! 4298: END;
! 4299: </PRE>
! 4300: <P>
! 4301: The top of the title is one line (a line has the height of thecharacters of
! 4302: the title) from the top of the report, which is also thetop of the editing
! 4303: window. The title is centered horizontally in thewindow (see <A
! 4304: href="#posdim">figure</A>).</P>
! 4305: <PRE>
! 4306: Summary : BEGIN
! 4307: VertPos : Top = Title . Bottom + 1.5;
! 4308: HorizPos : Left = Enclosing . Left + 2 cm;
! 4309: ...
! 4310: END;
! 4311: </PRE>
! 4312: <P>
! 4313: The top of the summary is place a line and a half below the bottom ofthe title
! 4314: and is shifted two centimeters from the side of the window.</P>
! 4315: </BLOCKQUOTE>
! 4316: <BLOCKQUOTE class="example">
! 4317: <P>
! 4318: <STRONG>Example:</STRONG></P>
! 4319: <P>
! 4320: Suppose there is a <A name="expos2">Design</A>logical structure which contains
! 4321: graphical elements:</P>
! 4322: <PRE>
! 4323: Design = LIST OF (ElemGraph = GRAPHICS);
! 4324: </PRE>
! 4325: <P>
! 4326: The following rules allow the user to freely choose the position ofeach
! 4327: element when it is created:</P>
! 4328: <PRE>
! 4329: ElemGraph =
! 4330: BEGIN
! 4331: VertPos : Top = Enclosing . Top + 1 cm UserSpecified;
! 4332: HorizPos: Left = Enclosing . Left UserSpecified;
! 4333: ...
! 4334: END;
! 4335: </PRE>
! 4336: <P>
! 4337: Thus, when a graphical element is created, its default placement is atthe left
! 4338: of the window and 1 cm from the top, but the user can move itimmediately,
! 4339: simply by moving the mouse.</P>
! 4340: </BLOCKQUOTE>
! 4341: </DIV>
! 4342:
! 4343: <DIV class="subsection">
! 4344: <H3><A name="dimension">Box extents</A></H3>
! 4345:
! 4346: <P>
! 4347: The extents (height and width) of each box are defined by the two rules
! 4348: <TT>Height</TT> and <TT>Width</TT>. There are three types of extents: fixed,
! 4349: relative, and elastic.</P>
! 4350:
! 4351: <DIV class="subsubsection">
! 4352: <H4>Fixed extents</H4>
! 4353:
! 4354: <P>
! 4355: A fixed dimension sets the height or width of the box independently of all
! 4356: other boxes. It is expressed in <A href="#distunits">distance units</A>. The
! 4357: extent can be followed by the <TT>UserSpecified</TT> keyword which indicates
! 4358: that when the element to which the rule applies is being created, the editor
! 4359: will ask the user to specify the extent himself, using the mouse. In this
! 4360: case, the extent specified in the rule is a default extent which is suggested
! 4361: to the user but can be modified. The <TT>UserSpecified</TT> keyword can be
! 4362: used either in the <TT>Height</TT> rule, the <TT>Width</TT> rule, or both.</P>
! 4363: <P>
! 4364: A fixed extent rule can be ended by the <TT>Min</TT> keyword, which signifies
! 4365: that the indicated value is a minimum, and that, if the contents of the box
! 4366: require it, a larger extent is possible.</P>
! 4367: <PRE>
! 4368: 'Height' ':' Dimension
! 4369: 'Width' ':' Dimension
! 4370: Dimension = AbsDist [ 'UserSpecified' ] [ 'Min' ] /
! 4371: ...
! 4372: </PRE>
! 4373: <BLOCKQUOTE class="example">
! 4374: <P>
! 4375: <STRONG>Example:</STRONG></P>
! 4376: <P>
! 4377: Continuing with the <A href="#expos2">previous example</A>, it is possibleto
! 4378: allow the user to choose the size of each graphical element as itis
! 4379: created:</P>
! 4380: <PRE>
! 4381: ElemGraph : BEGIN
! 4382: Width : 2 cm UserSpecified;
! 4383: Height : 1 cm UserSpecified;
! 4384: ...
! 4385: END;
! 4386: </PRE>
! 4387: <P>
! 4388: Thus, when a graphical element is create, it is drawn by default with a width
! 4389: of 2 cm and a height of 1 cm, but the user is free to resize it immediately
! 4390: with the mouse.</P>
! 4391: <PRE>
! 4392: Summary : BEGIN
! 4393: Height : 5 cm Min;
! 4394: ...
! 4395: END;
! 4396: Keywords : BEGIN
! 4397: VertPos : Top = Summary . Bottom;
! 4398: ...
! 4399: END;
! 4400: </PRE>
! 4401: </BLOCKQUOTE>
! 4402: </DIV>
! 4403:
! 4404: <DIV class="subsubsection">
! 4405: <H4>Relative extents</H4>
! 4406:
! 4407: <P>
! 4408: A relative extent determines the extent as a function of the extent of another
! 4409: box, just as a relative position places a box in relation to another. The
! 4410: reference box in an extent rule is designated using the same syntax as is used
! 4411: in a relative position rule. It is followed by a period and a <TT>Height</TT>
! 4412: or <TT>Width</TT> keyword, depending on the extent being referred to. Next
! 4413: comes the relation between the extent being defined and the extent of the
! 4414: reference box. This relation can be either a percentage or a difference.</P>
! 4415: <P>
! 4416: A percentage is indicated by a star (the multiplication symbol) followed by
! 4417: the numeric percentage value (which may be greater than or less than 100) and
! 4418: the percent (`%') character. A difference is simply indicated by a signed
! 4419: difference.</P>
! 4420: <P>
! 4421: If the rule appears in the presentation rules of a numeric attribute, the
! 4422: percentage value can be replaced by the name of the attribute. This attribute
! 4423: is then used as a percentage. The attribute can also be used as part of a <A
! 4424: href="#distance">difference</A>.</P>
! 4425: <P>
! 4426: Just as with a fixed extent, a relative extent rule can end with the
! 4427: <TT>Min</TT> keyword, which signifies that the extent is a minimum and that,
! 4428: if the contents of the box require it, a larger extent is possible.</P>
! 4429: <P>
! 4430: A special case of relative extent rules is:</P>
! 4431: <PRE>
! 4432: Height : Enclosed . Height;
! 4433: </PRE>
! 4434: <P>
! 4435: or</P>
! 4436: <PRE>
! 4437: Width : Enclosed . Width;
! 4438: </PRE>
! 4439: <P>
! 4440: which specifies that the box has a height (or width) such that itencloses all
! 4441: the boxes which it contains, excluding boxes having a rule<TT>VertOverflow:
! 4442: Yes;</TT>ou <TT>HorizOverflow:Yes;</TT>.</P>
! 4443: <P>
! 4444: <STRONG>Note:</STRONG> character strings (type <TT>TEXT_UNIT</TT>) generally
! 4445: must use the sum of the widths of the characters which compose them as their
! 4446: width, which is expressed by the rule:</P>
! 4447: <PRE>
! 4448: TEXT_UNIT :
! 4449: Width : Enclosed . Width;
! 4450: </PRE>
! 4451: <P>
! 4452: If this rule is not the default <TT>Width</TT>rule, it must be givenexplicitly
! 4453: in the <TT>RULES</TT>section which defines the presentationrules of the
! 4454: logical elements.</P>
! 4455: <PRE>
! 4456: 'Height' ':' Extent
! 4457: 'Width' ':' Extent
! 4458: Extent = Reference '.' HeightWidth [ Relation ]
! 4459: [ 'Min' ] / ...
! 4460: HeightWidth ='Height' / 'Width' .
! 4461: Relation ='*' ExtentAttr '%' / Distance .
! 4462: ExtentAttr = ExtentVal / AttrID .
! 4463: ExtentVal = NUMBER .
! 4464: </PRE>
! 4465: <BLOCKQUOTE class="example">
! 4466: <P>
! 4467: <STRONG>Example:</STRONG></P>
! 4468: <P>
! 4469: Completing the <A href="#expos1">above example</A>, it is possible tospecify
! 4470: that the report takes its width from the editing window andits height from the
! 4471: size of its contents (this can obviously begreater than that of the
! 4472: window):</P>
! 4473: <PRE>
! 4474: Report : BEGIN
! 4475: Width : Enclosing . Width;
! 4476: Height : Enclosed . Height;
! 4477: ...
! 4478: END;
! 4479: </PRE>
! 4480: <P>
! 4481: Then, the following rules make the title occupy 60% of the width ofthe report
! 4482: (which is that of the window) and is broken into centeredlines of this width
! 4483: (see the <A href="#linerule"><TT>Line</TT> rule</A>).</P>
! 4484: <PRE>
! 4485: Title : BEGIN
! 4486: Width : Enclosing . Width * 60%;
! 4487: Height : Enclosed . Height;
! 4488: Line;
! 4489: Adjust : VMiddle;
! 4490: ...
! 4491: END;
! 4492: </PRE>
! 4493: <P>
! 4494: The summary occupy the entire width of the window, with the exceptionof a 2 cm
! 4495: margin reserved by the horizontal position rule:</P>
! 4496: <PRE>
! 4497: Summary : BEGIN
! 4498: Width : Enclosing . Width - 2 cm;
! 4499: Height : Enclosed . Height;
! 4500: ...
! 4501: END;
! 4502: </PRE>
! 4503: <P>
! 4504: This set of rules, plus the <A href="#reportexample">position rules given
! 4505: above</A>, produce the layout of boxes shown in the following<A
! 4506: href="#posdim">figure</A>.</P>
! 4507:
! 4508: <DIV class="figure">
! 4509: <HR>
! 4510: <PRE>
! 4511: -------------------------------------------------------------
! 4512: | Window and Report ^ |
! 4513: | | 1 line |
! 4514: | v |
! 4515: | ------------------------------------- |
! 4516: | | | |
! 4517: : 20% : Title : 20% :
! 4518: :<--------->: :<--------->:
! 4519: : : 60% : :
! 4520: : :<--------------------------------->: :
! 4521: | | | |
! 4522: | ------------------------------------- |
! 4523: | ^ |
! 4524: | | 1.5 line |
! 4525: | | |
! 4526: | v |
! 4527: | ---------------------------------------------------|
! 4528: | 2 cm | |
! 4529: |<------>| Summary |
! 4530: : : :
! 4531: </PRE>
! 4532: <P align=center>
! 4533: <EM><A name="posdim">Box position and extent</A><EM></EM></EM></P>
! 4534: <HR>
! 4535: </DIV>
! 4536: </BLOCKQUOTE>
! 4537: </DIV>
! 4538:
! 4539: <DIV class="subsubsection">
! 4540: <H4>Elastic extents</H4>
! 4541:
! 4542: <P>
! 4543: The last type of extent is the elastic extent. Either one or both extents can
! 4544: be elastic. A box has an elastic extent when two opposite sides are linked by
! 4545: distance constraints to two sides or axes of other boxes.</P>
! 4546: <P>
! 4547: One of the sides of the elastic box is linked by a position rule
! 4548: (<TT>VertPos</TT> or <TT>HorizPos</TT>) to a neighboring box. The other side
! 4549: is link to another box by a <TT>Height</TT> or <TT>Width</TT> rule, which
! 4550: takes the same form as the position rule. For the elastic box itself, the
! 4551: notions of sides (left or right, top or bottom) are fuzzy, since the movement
! 4552: of either one of the two reference boxes can, for example, make the left side
! 4553: of the elastic box move to the right of its right side. This is not
! 4554: important. The only requirement is that the two sides of the elastic box used
! 4555: in the position and extent rule are opposite sides of the box.</P>
! 4556: <PRE>
! 4557: 'Height' ':' Extent
! 4558: 'Width' ':' Extent
! 4559: Extent = HPos / VPos / ...
! 4560: </PRE>
! 4561: <BLOCKQUOTE class="example">
! 4562: <P>
! 4563: <STRONG>Example:</STRONG></P>
! 4564: <P>
! 4565: Suppose we want to draw an elastic arrow or line between the middle ofthe
! 4566: bottom side of box A and the upper left corner of box B. To dothis, we would
! 4567: define a graphics box whose upper left corner coincideswith the middle of the
! 4568: bottom side of A (a position rule) and whoselower right corner coincides with
! 4569: with the upper left corner of B(dimension rules):</P>
! 4570: <PRE>
! 4571: LinkedBox :
! 4572: BEGIN
! 4573: VertPos : Top = A .Bottom;
! 4574: HorizPos : Left = A . VMiddle;
! 4575: Height : Bottom = B . Top;
! 4576: Width : Right = B . Left;
! 4577: END;
! 4578: </PRE>
! 4579: </BLOCKQUOTE>
! 4580: <BLOCKQUOTE class="example">
! 4581: <P>
! 4582: <STRONG>Example:</STRONG></P>
! 4583: <P>
! 4584: The element SectionTitle creates a presentation box called SectionNumwhich
! 4585: contains the number of the section. Suppose we want to alignthe SectionNum
! 4586: and SectionTitle horizontally, have the SectionNum takeits width from its
! 4587: contents (the section number), have theSectionTitle box begin 0.5 cm to the
! 4588: right of the SectionNum box andend at the right edge of its enclosing box.
! 4589: This would make theSectionTitle box elastic, since its width is defined by the
! 4590: positionof its left and right sides. The following rules produce this
! 4591: effect:</P>
! 4592: <PRE>
! 4593: SectionNum :
! 4594: BEGIN
! 4595: HorizPos : Left = Enclosing . Left;
! 4596: Width : Enclosed . Width;
! 4597: ...
! 4598: END;
! 4599:
! 4600: SectionTitle :
! 4601: BEGIN
! 4602: HorizPos : Left = SectionNum . Right + 0.5 cm;
! 4603: Width : Right = Enclosing . Right;
! 4604: ...
! 4605: END;
! 4606: </PRE>
! 4607: </BLOCKQUOTE>
! 4608: </DIV>
! 4609: </DIV>
! 4610:
! 4611: <DIV class="subsection">
! 4612: <H3>Overflow</H3>
! 4613:
! 4614: <P>
! 4615: A boxes corresponding to a structural element normally contain all boxes
! 4616: corresponding to the elements of its subtree. However, in some cases, it
! 4617: could be necessary to allow a box to jut out from its parent box. Two
! 4618: presentation rules indicate that such an overflow is allowed, one for
! 4619: horizontal overflow, one for vertical overflow.</P>
! 4620: <P>
! 4621: Each of these rules is expressed by a keyword followed by a colon and the
! 4622: keyword <TT>Yes</TT> or <TT>No</TT>.</P>
! 4623: <PRE>
! 4624: 'VertOverflow' ':' Boolean /
! 4625: 'HorizOverflow' ':' Boolean .
! 4626: Boolean = 'Yes' / 'No' .
! 4627: </PRE>
! 4628: </DIV>
! 4629:
! 4630: <DIV class="subsection">
! 4631: <H3>Inheritance</H3>
! 4632:
! 4633: <P>
! 4634: A presentation parameter can be defined by reference to the same parameter of
! 4635: another box in the tree of boxes. These structural links are expressed by
! 4636: kinship. The reference box can be that of the element immediately above in
! 4637: the structure (<TT>Enclosing</TT>), two levels above (<TT>GrandFather</TT>),
! 4638: immediately below (<TT>Enclosed</TT>) or immediately before
! 4639: (<TT>Previous</TT>). In the case of a presentation box, and only in that
! 4640: case, the reference box may be the element which created the presentation box
! 4641: (<TT>Creator</TT>).</P>
! 4642: <P>
! 4643: Kinship is expressed in terms of the logical structure of the document and not
! 4644: in terms of the tree of boxes. The presentation box cannot transmit any of
! 4645: their parameters by inheritance; only structured element boxes can do so. As
! 4646: an example, consider an element B which follows an element A in the logical
! 4647: structure. The element B creates a presentation box P in front of itself,
! 4648: using the <TT>CreateBefore</TT> rule (see the <A href="#creation">creation
! 4649: rules</A>). If element B's box inherits its character style using the
! 4650: <TT>Previous</TT> kinship operation, it gets its character style from A's box,
! 4651: not from P's box. Inheritance works differently for positions and extents,
! 4652: which can refer to presentation boxes.</P>
! 4653: <P>
! 4654: The inherited parameter value can be the same as that of the reference box.
! 4655: This is indicated by an equals sign. However, for numeric parameters, a
! 4656: different value can be obtained by adding or subtracting a number from the
! 4657: reference box's parameter value. Addition is indicated by a plus sign before
! 4658: the number, while subtraction is specified with a minus sign. The value of a
! 4659: parameter can also be given a maximum (if the sign is a plus) or minimum (if
! 4660: the sign is a minus).</P>
! 4661: <P>
! 4662: If the rule is being applied to a numeric attribute, the number to add or
! 4663: subtract can be replaced by the attribute name. The value of a maximum or
! 4664: minimum may also be replaced by an attribute name. In these cases, the value
! 4665: of the attribute is used.</P>
! 4666: <PRE>
! 4667: Inheritance = Kinship InheritedValue .
! 4668: Kinship ='Enclosing' / 'GrandFather' / 'Enclosed' /
! 4669: 'Previous' / 'Creator' .
! 4670: InheritedValue ='+' PosIntAttr [ 'Max' maximumA ] /
! 4671: '-' NegIntAttr [ 'Min' minimumA ] /
! 4672: '=' .
! 4673: PosIntAttr = PosInt / AttrID .
! 4674: PosInt = NUMBER .
! 4675: NegIntAttr = NegInt / AttrID .
! 4676: NegInt = NUMBER .
! 4677: maximumA = maximum / AttrID .
! 4678: maximum = NUMBER .
! 4679: minimumA = minimum / AttrID .
! 4680: minimum = NUMBER .
! 4681: </PRE>
! 4682: <P>
! 4683: The parameters which can be obtained by inheritance are justification,
! 4684: hyphenation, interline spacing, character font (font family), font style, font
! 4685: size, visibility, indentation, underlining, alignment of text, stacking order
! 4686: of objects, the style and thickness of lines, fill pattern and the colors of
! 4687: lines and characters.</P>
! 4688: </DIV>
! 4689:
! 4690: <DIV class="subsection">
! 4691: <H3><A name="linerule">Line breaking</A></H3>
! 4692:
! 4693: <P>
! 4694: The <TT>Line</TT> rule specifies that the contents of the box should be broken
! 4695: into lines: the boxes included in the box to which this rule is attached are
! 4696: displayed one after the other, from left to right, with their horizontal
! 4697: reference axes aligned so that they form a series of lines. The length of
! 4698: these lines is equal to the width of the box to which the <TT>Line</TT> rule
! 4699: is attached.</P>
! 4700: <P>
! 4701: When an included box overflows the current line, it is either carried forward
! 4702: to the next line, cur, or left the way it is. The <A
! 4703: href="#breakcond"><TT>LineBreak</TT> rule</A> is used to allow or prevent the
! 4704: breaking of included boxes. If the included box is not breakable but is
! 4705: longer than the space remaining on the line, it is left as is. When a
! 4706: character string box is breakable, the line is broken between words or, if
! 4707: necessary, by <A href="#hyphenaterule">hyphenating a word</A>. When a
! 4708: compound box is breakable, the box is transparent in regard to line breaking.
! 4709: The boxes included in the compound box are treated just like included boxes
! 4710: which have the <TT>LineBreak</TT> rule. Thus, it is possible to traverse a
! 4711: complete subtree of boxes to line break the text leaves of a complex
! 4712: structure.</P>
! 4713: <P>
! 4714: The relative position rules of the included boxes are ignored, since the boxes
! 4715: will be placed according to the line breaking rules.</P>
! 4716: <P>
! 4717: The <TT>Line</TT> rule does not have a parameter. The characteristics of the
! 4718: lines that will be constructed are determined by the <TT>LineSpacing</TT>,
! 4719: <TT>Indent</TT>, <TT>Adjust</TT>, <TT>Justify</TT>, and <TT>Hyphenate</TT>
! 4720: rules. Moreover, the <A href="#inlinerule"><TT>Inline</TT> rule</A> permits
! 4721: the exclusion of certain elements from the line breaking process.</P>
! 4722: <P>
! 4723: When the <TT>Line</TT> rule appears in the rules sequence of a non-primary
! 4724: view, it applies only to that view, but when the <TT>Line</TT> rule appears in
! 4725: the rules sequence of the primary view, it also applies to the other views by
! 4726: default, except for those views which explicitly invoke the <TT>NoLine</TT>
! 4727: rule. Thus, the <TT>NoLine</TT> rule can be used in a non-primary view to
! 4728: override the primary view's <TT>Line</TT> rule. The <TT>NoLine</TT> rule must
! 4729: not be used with the primary view because the absence of the <TT>Line</TT>
! 4730: rule has the same effect. Like the <TT>Line</TT> rule, the <TT>NoLine</TT>
! 4731: rule does not take any parameters.</P>
! 4732: <PRE>
! 4733: 'Line'
! 4734: 'NoLine'
! 4735: </PRE>
! 4736:
! 4737: <DIV class="subsubsection">
! 4738: <H4><A name="linespacing">Line spacing</A></H4>
! 4739:
! 4740: <P>
! 4741: The <TT>LineSpacing</TT> rule defines the line spacing to be used in the line
! 4742: breaking process. The line spacing is the distance between the baselines
! 4743: (horizontal reference axis) of the successive lines produced by the
! 4744: <TT>Line</TT> rule. The value of the line spacing can be specified as a
! 4745: constant or by inheritance. It is expressed in any of the available <A
! 4746: href="#distunits">distance units</A>.</P>
! 4747: <P>
! 4748: Inheritance allows the value to be obtained from a relative in the structure
! 4749: tree, either without change (an equals sign appears after the inheritance
! 4750: keyword), with a positive difference (a plus sign), or a negative difference
! 4751: (a minus sign). When the rule uses a difference, the value of the difference
! 4752: follows the sign and is expressed as a <A href="#distunits">distance</A>.</P>
! 4753: <PRE>
! 4754: 'LineSpacing' ':' DistOrInherit
! 4755: DistOrInherit = Kinship InheritedDist / Distance .
! 4756: InheritedDist = '=' / '+' AbsDist / '-' AbsDist .
! 4757: </PRE>
! 4758: <P>
! 4759: When the line spacing value (or its difference from another element) is
! 4760: expressed in relative units, it changes with the size of the characters. Thus,
! 4761: when a larger font is chosen for a part of the document, the line spacing of
! 4762: that part expands proportionally. In contrast, when the line spacing value is
! 4763: expressed in absolute units (centimeters, inches, typographer's points), it is
! 4764: independent of the characters, which permits the maintenance of a consistent
! 4765: line spacing, whatever the character font. Either approach can be taken,
! 4766: depending on the desired effect.</P>
! 4767: </DIV>
! 4768:
! 4769: <DIV class="subsubsection">
! 4770: <H4>First line indentation</H4>
! 4771:
! 4772: <P>
! 4773: The <TT>Indent</TT> rule is used to specify the indentation of the first line
! 4774: of the elements broken into lines by the <TT>Line</TT> function. The
! 4775: indentation determines how far the first line of the element is shifted with
! 4776: respect to the other lines of the same element. It can be specified as a
! 4777: constant or by inheritance. The constant value is a positive integer (shifted
! 4778: to the right; the sign is optional), a negative integer (shifted to the left)
! 4779: or zero (no shift). All available <A href="#distunits">units</A> can be
! 4780: used.</P>
! 4781: <P>
! 4782: Indentation can be defined for any box, regardless of whether the box is line
! 4783: broken, and transmitted by inheritance to elements that are line broken. The
! 4784: size of the indentation is specified in the same manner as the <A
! 4785: href="#linespacing">line spacing</A>.</P>
! 4786: <PRE>
! 4787: 'Indent' ':' DistOrInherit
! 4788: </PRE>
! 4789: </DIV>
! 4790:
! 4791: <DIV class="subsubsection">
! 4792: <H4>Alignment</H4>
! 4793:
! 4794: <P>
! 4795: The alignment style of the lines constructed during line breaking is defined
! 4796: by the <TT>Adjust</TT> rule. The alignment value can be a constant or
! 4797: inherited. A constant value is specified by a keyword:</P>
! 4798: <UL>
! 4799: <LI><TT>Left</TT>: at the left edge,
! 4800: <LI><TT>Right</TT>: at the right edge,
! 4801: <LI><TT>VMiddle</TT>: centered
! 4802: <LI><TT>LeftWithDots</TT>: at the left edge with a dotted linefilling out the
! 4803: last line up to the right edge of the line breaking box.
! 4804: </UL>
! 4805: <P>
! 4806: An inherited value can only be the same as that of the reference box and is
! 4807: specified by a kinship keyword followed by an equals sign.</P>
! 4808: <PRE>
! 4809: 'Adjust' ':' AlignOrInherit
! 4810: AlignOrInherit = Kinship '=' / Alignment .
! 4811: Alignment = 'Left' / 'Right' / 'VMiddle' /
! 4812: 'LeftWithDots' .
! 4813: </PRE>
! 4814: </DIV>
! 4815:
! 4816: <DIV class="subsubsection">
! 4817: <H4>Justification</H4>
! 4818:
! 4819: <P>
! 4820: The <TT>Justify</TT> rule indicates whether the lines contained in the box and
! 4821: produced by a <TT>Line</TT> rule should be extended horizontally to occupy the
! 4822: entire width of their enclosing box. The first and last lines are treated
! 4823: specially: the position of the beginning of the first line is fixed by the
! 4824: <TT>Indent</TT> rule and last line is not extended. The justification
! 4825: parameter defined by this rule takes a boolean value, which can be a constant
! 4826: or inherited. A constant boolean value is expressed by either the
! 4827: <TT>Yes</TT> or the <TT>No</TT> keyword. An inherited value can only be the
! 4828: same as that of the reference box and is specified by a kinship keyword
! 4829: followed by an equals sign.</P>
! 4830: <PRE>
! 4831: 'Justify' ':' BoolInherit
! 4832: BoolInherit = Boolean / Kinship '=' .
! 4833: Boolean ='Yes' / 'No' .
! 4834: </PRE>
! 4835: <P>
! 4836: When the lines are justified, the alignment parameter specified in the
! 4837: <TT>Adjust</TT> rule has no influence, other than on the last line produced.
! 4838: This occurs because, when the other are extended to the limits of the box, the
! 4839: alignment style is no longer perceptible.</P>
! 4840: <BLOCKQUOTE class="example">
! 4841: <P>
! 4842: <STRONG>Example:</STRONG></P>
! 4843: <P>
! 4844: An important use of inheritance is to vary the characteristics oflines for an
! 4845: element type (for example, Paragraph) according to theenclosing environment
! 4846: (for example, Summary or Section), and thusobtain different line breaking
! 4847: styles for the same elements when theyappear in different environments. The
! 4848: following rules specify thatparagraphs inherit their alignment, justification,
! 4849: and line spacing:</P>
! 4850: <PRE>
! 4851: Paragraph :
! 4852: BEGIN
! 4853: Justify : Enclosing = ;
! 4854: LineSpacing : Enclosing = ;
! 4855: Adjust : Enclosing =;
! 4856: Line;
! 4857: END;
! 4858: </PRE>
! 4859: <P>
! 4860: If the alignment, justification, and line spacing of the Sectionand Summary
! 4861: elements is fixed:</P>
! 4862: <PRE>
! 4863: Section :
! 4864: BEGIN
! 4865: Adjust : Left;
! 4866: Justify : Yes;
! 4867: LineSpacing : 1;
! 4868: END;
! 4869: Summary :
! 4870: BEGIN
! 4871: Adjust : VMiddle;
! 4872: Justify : No;
! 4873: LineSpacing : 1.3;
! 4874: END;
! 4875: </PRE>
! 4876: <P>
! 4877: then the paragraphs appearing in sections are justified with a simpleline
! 4878: spacing while those appearing in summaries are centered and notjustified and
! 4879: have a larger line spacing. These are nevertheless thevery same type of
! 4880: paragraph defined in the logical structure schema.</P>
! 4881: </BLOCKQUOTE>
! 4882: </DIV>
! 4883:
! 4884: <DIV class="subsubsection">
! 4885: <H4><A name="hyphenaterule">Hyphenation</A></H4>
! 4886:
! 4887: <P>
! 4888: The <TT>Hyphenate</TT> rule indicates whether or not words should be broken by
! 4889: hyphenation at the end of lines. It affects the lines produced by the
! 4890: <TT>Line</TT> rule and contained in the box carrying the <TT>Hyphenate</TT>
! 4891: rule.</P>
! 4892: <P>
! 4893: The hyphenation parameter takes a boolean value, which can be either constant
! 4894: or inherited. A constant boolean value is expressed by either the
! 4895: <TT>Yes</TT> or the <TT>No</TT> keyword. An inherited value can only be the
! 4896: same as that of the reference box and is specified by a kinship keyword
! 4897: followed by an equals sign.</P>
! 4898: <PRE>
! 4899: 'Hyphenate' ':' BoolInherit
! 4900: BoolInherit = Boolean / Kinship '=' .
! 4901: Boolean = 'Yes' / 'No' .
! 4902: </PRE>
! 4903: </DIV>
! 4904:
! 4905: <DIV class="subsubsection">
! 4906: <H4><A name="inlinerule">Avoiding line breaking</A></H4>
! 4907:
! 4908: <P>
! 4909: The <TT>InLine</TT> rule is used to specify that a box that would otherwise
! 4910: participate in line breaking asked for by the <TT>Line</TT> rule of an
! 4911: enclosing box, instead avoids the line breaking process and positions itself
! 4912: according to the <TT>HorizPos</TT> and <TT>VertPos</TT> rules that apply to
! 4913: it. When the <TT>InLine</TT> rule applies to a box which would not be line
! 4914: broken, it has no effect.</P>
! 4915: <P>
! 4916: The rule is expressed by the <TT>InLine</TT> keyword followed by a colon and
! 4917: the keyword <TT>Yes</TT>, if the box should participate in line breaking, or
! 4918: the keyword <TT>No</TT>, if it should not. This is the only form possible:
! 4919: this rule cannot be inherited. Moreover, it can only appear in the rules of
! 4920: the primary view and applies to all views defined in the presentation
! 4921: schema.</P>
! 4922: <PRE>
! 4923: 'InLine' ':' Boolean .
! 4924: Boolean = 'Yes' / 'No' .
! 4925: </PRE>
! 4926: <BLOCKQUOTE class="example">
! 4927: <P>
! 4928: <STRONG>Example:</STRONG></P>
! 4929: <P>
! 4930: Suppose the structure schema defines a logical attribute
! 4931: called<TT>New</TT>which is used to identify the passages in a document which
! 4932: wererecently modified. It would be nice to have the presentation schemamake a
! 4933: bar appear in the left margin next to each passage having
! 4934: the<TT>New</TT>attribute. A new passage can be an entire element, such asa
! 4935: paragraph or section, or it can be some words in the middle of aparagraph. To
! 4936: produce the desired effect, the <TT>New</TT>attribute isgiven a creation rule
! 4937: which generates a <TT>VerticalBar</TT>presentationbox.</P>
! 4938: <P>
! 4939: When the <TT>New</TT> attribute is attached to a character string which is
! 4940: inside a line broken element (inside a paragraph, for example), the bar is one
! 4941: of the elements which participates in line breaking and it is placed normally
! 4942: in the current line, at the end of the character string which has the
! 4943: attribute. To avoid this, the <TT>InLine</TT> rule is used in the following
! 4944: way:</P>
! 4945: <PRE>
! 4946: BOXES
! 4947: VerticalBar:
! 4948: BEGIN
! 4949: Content: Graphics 'l';
! 4950: HorizPos: Left = Root . Left;
! 4951: VertPos: Top = Creator . Top;
! 4952: Height: Bottom = Creator . Bottom;
! 4953: Width: 1 pt;
! 4954: InLine: No;
! 4955: ...
! 4956: END;
! 4957: ...
! 4958: ATTRIBUTES
! 4959: Nouveau:
! 4960: BEGIN
! 4961: CreateAfter(VerticalBar);
! 4962: END;
! 4963: </PRE>
! 4964: </BLOCKQUOTE>
! 4965: </DIV>
! 4966: </DIV>
! 4967:
! 4968: <DIV class="subsection">
! 4969: <H3><A name="breakcond">Page breaking and line breaking conditions</A></H3>
! 4970:
! 4971: <P>
! 4972: Pages are constructed by the editor in accordance with the model specified by
! 4973: a <A href="#page"><TT>Page</TT> rule</A>. The page model describes only the
! 4974: composition of the pages but does not give any rules for breaking different
! 4975: element types across pages. Now, it is possible that certain elements must
! 4976: not be cut by page breaks, while others can be cut anywhere. The
! 4977: <TT>PageBreak</TT>, <TT>NoBreak1</TT>, and <TT>NoBreak2</TT> rules are used to
! 4978: specify the conditions under which each element type can be cut.</P>
! 4979: <P>
! 4980: The <TT>PageBreak</TT> rule is used to indicate whether or not the box can be
! 4981: cut during the construction of pages. If cutting is authorized, the box can
! 4982: be cut, with one part appearing at the bottom of a page and the other part
! 4983: appearing at the top of the next page. The rule is formed by the
! 4984: <TT>PageBreak</TT> keyword followed by a colon and a constant boolean value
! 4985: (<TT>Yes</TT> or <TT>No</TT>). This is the only form possible: this rule
! 4986: cannot be inherited. Moreover, it can only appear in the rules of the primary
! 4987: view and applies to all views defined in the presentation schema.</P>
! 4988: <P>
! 4989: Whether objects can be cut by line breaks can be controlled in a similar way
! 4990: using the <TT>LineBreak</TT> rule. This rule allows the specification of
! 4991: whether or not the box can be cut during the construction of lines. If
! 4992: cutting is authorized, the box can be cut, with one part appearing at the end
! 4993: of a line and the other part appearing at the beginning of the next line. The
! 4994: rule is formed by the <TT>LineBreak</TT> keyword followed by a colon and a
! 4995: constant boolean value (<TT>Yes</TT> or <TT>No</TT>). This is the only form
! 4996: possible: this rule cannot be inherited. Moreover, it can only appear in the
! 4997: rules of the primary view and applies to all views defined in the presentation
! 4998: schema.</P>
! 4999: <PRE>
! 5000: 'PageBreak' ':' Boolean .
! 5001: 'LineBreak' ':' Boolean .
! 5002: Boolean = 'Yes' / 'No' .
! 5003: </PRE>
! 5004: <P>
! 5005: When a box can be cut by a page break, it is possible that a page break will
! 5006: fall an inappropriate spot, creating, for example, a widow or orphan, or
! 5007: separating the title of a section from the first paragraph of the section. The
! 5008: <TT>NoBreak1</TT> and <TT>NoBreak2</TT> rules are used to avoid this. They
! 5009: specify that the box of the element type to which they apply cannot be cut
! 5010: within a certain zone above (<TT>NoBreak1</TT> rule) or below
! 5011: (<TT>NoBreak2</TT> rule). These two rules specify the height of the zones in
! 5012: which page breaks are prohibited.</P>
! 5013: <P>
! 5014: The <TT>NoBreak1</TT> and <TT>NoBreak2</TT> rules give the height of the zone
! 5015: in which page breaking is prohibited. The height is given as a constant value
! 5016: using any of the <A href="#distunits">available units</A>, absolute or
! 5017: relative. The value may not be inherited.</P>
! 5018: <PRE>
! 5019: 'NoBreak1' ':' AbsDist .
! 5020: 'NoBreak2' ':' AbsDist .
! 5021: </PRE>
! 5022: <BLOCKQUOTE class="example">
! 5023: <P>
! 5024: <STRONG>Example:</STRONG></P>
! 5025: <P>
! 5026: The following rules prevent widows and orphans in a paragraph:</P>
! 5027: <PRE>
! 5028: Paragraph :
! 5029: BEGIN
! 5030: NoBreak1 : 2;
! 5031: NoBreak2 : 2;
! 5032: END;
! 5033: </PRE>
! 5034: <P>
! 5035: This rule prevents a section title from becoming separated from thefirst
! 5036: paragraph of the section by prohibiting page breaks at thebeginning of the
! 5037: section rule:</P>
! 5038: <PRE>
! 5039: Section :
! 5040: NoBreak1 : 1.5 cm;
! 5041: </PRE>
! 5042: <P>
! 5043: Finally, this rule prevents a figure from being page broken in any way:</P>
! 5044: <PRE>
! 5045: Figure :
! 5046: PageBreak : No;
! 5047: </PRE>
! 5048: </BLOCKQUOTE>
! 5049: <P>
! 5050: The Thot editor constructs the document images displayed on the screen
! 5051: dynamically. As the user moves in the document or makes the document scroll
! 5052: in a window, the editor constructs the image to be displayed in little bits,
! 5053: filling the gaps which are produced in the course of these operations. It
! 5054: stops filling in the image when an element reaches the edge of the window in
! 5055: which the gap appears. If the appearance of the document is complex, it is
! 5056: possible that the image in incomplete, even though the edge of the window was
! 5057: reached. For example, an element might need to be presented to the side of
! 5058: the last element displayed, but its image was not constructed. The user will
! 5059: not know whether the element is really absent or if its image has simply not
! 5060: been constructed.</P>
! 5061: <P>
! 5062: The <TT>Gather</TT> rule is used to remedy this problem. When the rule
! 5063: <TT>Gather : Yes;</TT> is associated with an element type, the image of such
! 5064: elements is constructed as a block by the editor: it is never split up.</P>
! 5065: <P>
! 5066: The <TT>Gather</TT> rule may not appear in the <A
! 5067: href="#defaultpresrules">default rules</A>. Elements which do not have the
! 5068: <TT>Gather</TT> rule are considered susceptible to being split up during
! 5069: display. Thus, it is not necessary to use the <TT>Gather : No;</TT> form.
! 5070: This rule must be used prudently and only for those elements which truly need
! 5071: it. If used incorrectly, it can pointlessly increase the size of the image
! 5072: constructed by the editor and lead to excessive memory consumption by the
! 5073: editor.</P>
! 5074: <P>
! 5075: Like the <TT>PageBreak</TT> and <TT>LineBreak</TT> rules, the <TT>Gather</TT>
! 5076: rule can only appear in rules of the primary view and applies to all views
! 5077: defined in the presentation schema.</P>
! 5078: <PRE>
! 5079: 'Gather' ':' Boolean .
! 5080: </PRE>
! 5081: </DIV>
! 5082:
! 5083: <DIV class="subsection">
! 5084: <H3><A name="visib">Visibility</A></H3>
! 5085:
! 5086: <P>
! 5087: The visibility parameter is used to control which elements should or should
! 5088: not be displayed, based on context. An element can have different
! 5089: visibilities in different views. If an element's visibility is zero for a
! 5090: view, that element is not displayed in that view and does not occupy any space
! 5091: (its extents are zero).</P>
! 5092: <P>
! 5093: Visibility takes non-negative integer values (positive or zero). If values
! 5094: greater than 1 are used, they allow the user to choose a degree of visibility
! 5095: and, thus, to see only those boxes whose visibility parameter exceeds a
! 5096: certain threshold. This gives the user control over the granularity of the
! 5097: displayed images.</P>
! 5098: <P>
! 5099: The visibility parameter can be defined as a constant or by inheritance. If
! 5100: defined by inheritance, it cannot be based on the value of the next or
! 5101: previous box. Visibility can only be inherited from above.</P>
! 5102: <P>
! 5103: If it is a numeric attribute's presentation rule, the visibility can be
! 5104: specified by the attribute's name, in which case the value of the attribute is
! 5105: used.</P>
! 5106: <PRE>
! 5107: 'Visibility' ':' NumberInherit
! 5108: NumberInherit = Integer / AttrID / Inheritance .
! 5109: Integer = NUMBER .
! 5110: </PRE>
! 5111: <BLOCKQUOTE class="example">
! 5112: <P>
! 5113: <STRONG>Example:</STRONG></P>
! 5114: <P>
! 5115: Suppose that only <TT>Formula</TT>elements should be displayed in
! 5116: the<TT>MathView</TT>view. Then, the default rules should include:</P>
! 5117: <PRE>
! 5118: DEFAULT
! 5119: IN MathView Visibility:0;
! 5120: </PRE>
! 5121: <P>
! 5122: which makes all elements invisible in the <TT>MathView</TT>view.However, the
! 5123: <TT>Formula</TT>element also has a <TT>Visibility</TT>rule:</P>
! 5124: <PRE>
! 5125: Formula :
! 5126: IN MathView Visibility:5;
! 5127: </PRE>
! 5128: <P>
! 5129: which makes formulas, and only formulas, visible.</P>
! 5130: </BLOCKQUOTE>
! 5131: </DIV>
! 5132:
! 5133: <DIV class="subsection">
! 5134: <H3>Character style parameters</H3>
! 5135:
! 5136: <P>
! 5137: Four parameters are used to determine which characters are used to display
! 5138: text. They are size, font, style, and underlining.</P>
! 5139:
! 5140: <DIV class="subsubsection">
! 5141: <H4>Character size</H4>
! 5142:
! 5143: <P>
! 5144: The size parameter has two effects. First, it is used to specify the actual
! 5145: size and distance units for boxes defined in <A href="#distunits">relative
! 5146: units</A>. Second, it defines the size of the characters contained in the
! 5147: box.</P>
! 5148: <P>
! 5149: As a distance or length, the size can be expressed in abstract or absolute
! 5150: units. It can also be inherited. If it is not inherited, it is expressed
! 5151: simply as an integer followed by the <TT>pt</TT> keyword, which indicates that
! 5152: the size is expressed in typographer's points. The absence of the <TT>pt</TT>
! 5153: keyword indicates that it is in abstract units in which the value 1 represents
! 5154: the smallest size while the value 16 is the largest size. The relationship
! 5155: between these abstract sizes and the real character sizes is controlled by a
! 5156: table which can be modified statically or even dynamically during the
! 5157: execution of the Thot editor.</P>
! 5158: <P>
! 5159: If it is a numeric attribute's presentation rule, the value of the size
! 5160: parameter can be specified by the attribute's name, in which case the value of
! 5161: the attribute is used.</P>
! 5162: <P>
! 5163: <STRONG>Note:</STRONG> the only unit available for defining an absolute size
! 5164: is the typographer's point. Centimeters and inches may not be used.</P>
! 5165: <P>
! 5166: If the size is inherited, the rule must specify the relative from which to
! 5167: inherit and any difference from that relative's value. The difference can be
! 5168: expressed in either typographer's points or in abstract units. The maximum or
! 5169: minimum size can also be specified, but without specifying the type of unit:
! 5170: it is the same as was specified for the difference.</P>
! 5171: <P>
! 5172: In a numeric attribute's presentation rule, the difference in size can be
! 5173: indicated by the attribute's name, which means that the attribute's value
! 5174: should be used as the difference. The attribute can also be used as the
! 5175: minimum or maximum size.</P>
! 5176: <PRE>
! 5177: 'Size' ':' SizeInherit
! 5178: SizeInherit = SizeAttr [ 'pt' ] /
! 5179: Kinship InheritedSize .
! 5180: InheritedSize ='+' SizeAttr [ 'pt' ]
! 5181: [ 'Max' MaxSizeAttr ] /
! 5182: '-' SizeAttr [ 'pt' ]
! 5183: [ 'Min' MinSizeAttr ] /
! 5184: '=' .
! 5185: SizeAttr = Size / AttrID .
! 5186: Size = NUMBER .
! 5187: MaxSizeAttr = MaxSize / AttrID .
! 5188: MaxSize = NUMBER .
! 5189: MinSizeAttr = MinSize / AttrID .
! 5190: MinSize = NUMBER .
! 5191: </PRE>
! 5192: <BLOCKQUOTE class="example">
! 5193: <P>
! 5194: <STRONG>Example:</STRONG></P>
! 5195: <P>
! 5196: The rule</P>
! 5197: <PRE>
! 5198: Size : Enclosing - 2 pt Min 7;
! 5199: </PRE>
! 5200: <P>
! 5201: states that the character size is 2 points less than that of theenclosing box,
! 5202: but that it may not be less than 7 points, whatever theenclosing box's
! 5203: value.</P>
! 5204: <P>
! 5205: The following rules make the text of a report be displayed with medium-sized
! 5206: characters (for example, size 5), while the title is displayed with larger
! 5207: characters and the summary is displayed with smaller characters:</P>
! 5208: <PRE>
! 5209: Report :
! 5210: Size : 5;
! 5211: Title :
! 5212: Size : Enclosing + 2;
! 5213: Summary :
! 5214: Size : Enclosing - 1;
! 5215: </PRE>
! 5216: <P>
! 5217: Thus, the character sizes in the entire document can be changed bychanging the
! 5218: size parameter of the Report element, while preservingthe relationships
! 5219: between the sizes of the different elements.</P>
! 5220: </BLOCKQUOTE>
! 5221: </DIV>
! 5222:
! 5223: <DIV class="subsubsection">
! 5224: <H4><A name="style">Font and character style</A></H4>
! 5225:
! 5226: <P>
! 5227: The <TT>Font</TT> rule determines the font family to be used to display the
! 5228: characters contained in the box, while the <TT>Style</TT> rule determines
! 5229: their style. Thot recognizes three character fonts (Times, Helvetica, and
! 5230: Courier) and six styles: Roman, Italics, Bold, BoldItalics, Oblique, and
! 5231: BoldOblique.</P>
! 5232: <P>
! 5233: The font family and style can specified by a named constant or can be
! 5234: inherited. For the name of the font family only the first character is
! 5235: used.</P>
! 5236: <P>
! 5237: Only identical inheritance is allowed: the box takes the same font or style as
! 5238: the box from which it inherits. This is indicated by an equals sign after the
! 5239: kinship specification.</P>
! 5240: <BLOCKQUOTE class="example">
! 5241: <P>
! 5242: <STRONG>Example:</STRONG></P>
! 5243: <P>
! 5244: To specify that the summary uses the font family of the rest of thedocument,
! 5245: but in the italic style, the following rules are used:</P>
! 5246: <PRE>
! 5247: Summary :
! 5248: BEGIN
! 5249: Font : Enclosing =;
! 5250: Style : Italics;
! 5251: END;
! 5252: </PRE>
! 5253: </BLOCKQUOTE>
! 5254: </DIV>
! 5255:
! 5256: <DIV class="subsubsection">
! 5257: <H4><A name="underline">Underlining</A></H4>
! 5258:
! 5259: <P>
! 5260: The <TT>Underline</TT> rule is used to specify if the characters contained in
! 5261: a box should have lines drawn on or near them. There are four underlining
! 5262: styles: <TT>Underlined</TT>, <TT>Overlined</TT>, <TT>CrossedOut</TT>, and
! 5263: <TT>NoUnderline</TT>. The <TT>Thickness</TT> rule specifies the thickness of
! 5264: the line, <TT>Thin</TT> or <TT>Thick</TT>.</P>
! 5265: <P>
! 5266: As with font family and style, only identical inheritance is allowed: the box
! 5267: has the same underlining type as the box from which it inherits the value.
! 5268: This is indicated by an equals sign after the kinship specification.</P>
! 5269: <PRE>
! 5270: 'Underline' ':' UnderLineInherit /
! 5271: 'Thickness' ':' ThicknessInherit /
! 5272:
! 5273: UnderLineInherit = Kinship '=' / 'NoUnderline' /
! 5274: 'Underlined' /
! 5275: 'Overlined' / 'CrossedOut' .
! 5276: ThicknessInherit = Kinship '=' / 'Thick' / 'Thin' .
! 5277: </PRE>
! 5278: </DIV>
! 5279: </DIV>
! 5280:
! 5281: <DIV class="subsection">
! 5282: <H3>Stacking order</H3>
! 5283:
! 5284: <P>
! 5285: The <TT>Depth</TT> rule is used to define the stacking order of terminal boxes
! 5286: when multiple boxes at least partially overlap. This rule defines how the
! 5287: depth parameter, which is zero or a positive integer, is calculated. The
! 5288: depth parameter has a value for all boxes. For terminal boxes in the
! 5289: structure and for presentation boxes, the depth value is used during display
! 5290: and printing: the boxes with the lowest value overlap those with higher
! 5291: depths. For non-terminal boxes, the depth is not interpreted during display,
! 5292: but it is used to calculate the depth of terminal boxes by inheritance.</P>
! 5293: <P>
! 5294: Like most other rules, the depth rule is defined in the <A
! 5295: href="#defaultpresrules">default rules</A> of each presentation schema. Thus,
! 5296: there is always a depth value, even when it is not necessary because there is
! 5297: no overlapping. To avoid useless operations, a zero value can be given to the
! 5298: depth parameter, which signifies that overlapping is never a problem.</P>
! 5299: <P>
! 5300: The depth rule has the same form as the <A href="#visib">visibility rule</A>.
! 5301: It can be defined by inheritance or by a constant numeric value. When the rule
! 5302: is attached to a numeric attribute, it can take the value of that
! 5303: attribute.</P>
! 5304: <PRE>
! 5305: 'Depth' ':' NumberInherit
! 5306: </PRE>
! 5307: <BLOCKQUOTE class="example">
! 5308: <P>
! 5309: <STRONG>Example:</STRONG></P>
! 5310: <P>
! 5311: For a purely textual document, in which overlapping never poses aproblem, a
! 5312: single default <TT>Depth</TT>rule in the presentation schemais sufficient:</P>
! 5313: <PRE>
! 5314: DEFAULT
! 5315: Depth : 0;
! 5316: ...
! 5317: </PRE>
! 5318: <P>
! 5319: To make the text of examples appear on a light blue background, a presentation
! 5320: box is defined:</P>
! 5321: <PRE>
! 5322: BOXES
! 5323: BlueBG :
! 5324: BEGIN
! 5325: Content : Graphics 'R';
! 5326: Background : LightBlue3;
! 5327: FillPattern: backgroundcolor;
! 5328: Depth : 2;
! 5329: ...
! 5330: END;
! 5331: </PRE>
! 5332: <P>
! 5333: and is created by the <TT>Example</TT>element, which has the rules:</P>
! 5334: <PRE>
! 5335: RULES
! 5336: Example :
! 5337: BEGIN
! 5338: CreateFirst (BlueBG);
! 5339: Depth : 1;
! 5340: ...
! 5341: END;
! 5342: </PRE>
! 5343: <P>
! 5344: In this way, the text of an example (if it inherits its depth from
! 5345: itsancestor) will be superimposed on a light blue background, and not
! 5346: thereverse).</P>
! 5347: </BLOCKQUOTE>
! 5348: </DIV>
! 5349:
! 5350: <DIV class="subsection">
! 5351: <H3>Line Style</H3>
! 5352:
! 5353: <P>
! 5354: The <TT>LineStyle</TT> rule determines the style of line which should be used
! 5355: to draw all the elements contained in the box. The line style can be
! 5356: indicated by a name (<TT>Solid</TT>, <TT>Dashed</TT>, <TT>Dotted</TT>) or it
! 5357: can be inherited. Only elements of the graphic base type are affected by this
! 5358: rule, but it can be attached to any box and transmitted by inheritance to the
! 5359: graphic elements.</P>
! 5360: <P>
! 5361: Only identical inheritance is allowed: the box takes the same line style as
! 5362: the box from which it inherits. This is indicated by an equals sign after the
! 5363: kinship specification.</P>
! 5364: <PRE>
! 5365: 'LineStyle' ':' LineStyleInherit
! 5366: LineStyleInherit = Kinship '=' /
! 5367: 'Solid' / 'Dashed' / 'Dotted' .
! 5368: </PRE>
! 5369: <BLOCKQUOTE class="example">
! 5370: <P>
! 5371: <STRONG>Example:</STRONG></P>
! 5372: <P>
! 5373: To specify that, in Figures, the graphical parts should bedrawn in solid
! 5374: lines, the Figure element is given a rule using the<TT>Solid</TT>name:</P>
! 5375: <PRE>
! 5376: Figure :
! 5377: LineStyle : Solid;
! 5378: </PRE>
! 5379: <P>
! 5380: and the elements composing figures are given an inheritance rule:</P>
! 5381: <PRE>
! 5382: LineStyle : Enclosing =;
! 5383: </PRE>
! 5384: </BLOCKQUOTE>
! 5385: </DIV>
! 5386:
! 5387: <DIV class="subsection">
! 5388: <H3>Line thickness</H3>
! 5389:
! 5390: <P>
! 5391: The <TT>LineWeight</TT> rule determines the thickness of the lines of all
! 5392: graphical elements which appear in the box, no matter what their line style.
! 5393: Line thickness can be specified by a constant value or by inheritance. A
! 5394: constant value is a positive number followed by an optional unit specification
! 5395: (which is absent when using relative units). All available <A
! 5396: href="#distunits">distance units</A> can be used. Line thickness is expressed
! 5397: in the same way as <A href="#linespacing">line spacing</A>.</P>
! 5398: <PRE>
! 5399: 'LineWeight' ':' DistOrInherit
! 5400: </PRE>
! 5401: <P>
! 5402: Only elements of the graphic base type are affected by this rule, but it can
! 5403: be attached to any box and transmitted by inheritance to the graphic
! 5404: elements.</P>
! 5405: <BLOCKQUOTE class="example">
! 5406: <P>
! 5407: <STRONG>Example:</STRONG></P>
! 5408: <P>
! 5409: To specify that, in Figures, the graphical parts should be drawn withlines 0.3
! 5410: pt thick, the Figure element is given this rule:</P>
! 5411: <PRE>
! 5412: Figure :
! 5413: LineWeight : 0.3 pt;
! 5414: </PRE>
! 5415: <P>
! 5416: and the elements composing figures are given an inheritance rule:</P>
! 5417: <PRE>
! 5418: LineWeight : Enclosing =;
! 5419: </PRE>
! 5420: </BLOCKQUOTE>
! 5421: </DIV>
! 5422:
! 5423: <DIV class="subsection">
! 5424: <H3><A name="pattern">Fill pattern</A></H3>
! 5425:
! 5426: <P>
! 5427: The <TT>FillPattern</TT> rule determines the pattern used to fill closed
! 5428: graphical elements (circles, rectangles, etc.) which appear in the box. This
! 5429: pattern can be indicated by a named constant or by inheritance. The named
! 5430: constant identifies one of the patterns available in Thot. The names of the
! 5431: available patterns are: nopattern, foregroundcolor, backgroundcolor, gray1,
! 5432: gray2, gray3, gray4, gray5, gray6, gray7, horiz1, horiz2, horiz3, vert1,
! 5433: vert2, vert3, left1, left2, left3, right1, right2, right3, square1, square2,
! 5434: square3, lozenge, brick, tile, sea, basket.</P>
! 5435: <P>
! 5436: Like the other rules peculiar to graphics, <TT>LineStyle</TT> and
! 5437: <TT>LineWeight</TT>, only elements of the graphic base type are affected by
! 5438: the <TT>FillPattern</TT> rule, but the rule can be attached to any box and
! 5439: transmitted by inheritance to the graphic elements. As with the other rules
! 5440: specific to graphics, only identical inheritance is allowed.</P>
! 5441: <P>
! 5442: The <TT>FillPattern</TT> rule can also be used to determine whether or not
! 5443: text characters, symbols and bitmaps should be colored. For these element
! 5444: types (test, symbols, and images), the only valid values are nopattern,
! 5445: foregroundcolor, and backgroundcolor. When <TT>FillPattern</TT> has the value
! 5446: <TT>backgroundcolor</TT>, text characters, symbols, and bitmaps are given the
! 5447: color specified by the <A href="#colors"><TT>Background</TT> rule</A> which
! 5448: applies to these elements. When <TT>FillPattern</TT> has the value
! 5449: <TT>foregroundcolor</TT>, these same elements are given the color specified by
! 5450: the <A href="#colors"><TT>Foreground</TT> rule</A> which applies to these
! 5451: elements. In all other case, text characters are not colored.</P>
! 5452: <PRE>
! 5453: 'FillPattern' ':' NameInherit
! 5454: </PRE>
! 5455: <BLOCKQUOTE class="example">
! 5456: <P>
! 5457: <STRONG>Example:</STRONG></P>
! 5458: <P>
! 5459: To specify that, in Figures, the closed graphical elements should befilled
! 5460: with a pattern resembling a brick wall, the Figure element isgiven this
! 5461: rule:</P>
! 5462: <PRE>
! 5463: Figure :
! 5464: FillPattern : brick;
! 5465: </PRE>
! 5466: <P>
! 5467: and the elements composing figures are given an inheritance rule:</P>
! 5468: <PRE>
! 5469: FillPattern : Enclosing =;
! 5470: </PRE>
! 5471: </BLOCKQUOTE>
! 5472: </DIV>
! 5473:
! 5474: <DIV class="subsection">
! 5475: <H3><A name="colors">Colors</A></H3>
! 5476:
! 5477: <P>
! 5478: The <TT>Foreground</TT> and <TT>Background</TT> rules determine the foreground
! 5479: and background colors of the base elements which appear in the box. These
! 5480: colors cancan be specified with a named constant or by inheritance. The named
! 5481: constants specify one of the available colors in Thot. The available color
! 5482: names can be found in the file <TT>thot.color</TT>.</P>
! 5483: <P>
! 5484: In contrast to the preceding rules, the color rules affect all base elements
! 5485: the same way, no matter what their type (text, graphics, images, symbols), but
! 5486: they only affect base elements. The color rules can nevertheless be
! 5487: associated with any box and can be transmitted to the base elements by
! 5488: inheritance. Like the preceding rules, only inheritance of the same value is
! 5489: allowed.</P>
! 5490: <PRE>
! 5491: 'Foreground' ':' NameInherit
! 5492: 'Background' ':' NameInherit
! 5493: </PRE>
! 5494: <P>
! 5495: <STRONG>Note:</STRONG> text colors only appear for text elements whose <A
! 5496: href="#pattern">fill pattern</A> does not prevent the use of color.</P>
! 5497: <BLOCKQUOTE class="example">
! 5498: <P>
! 5499: <STRONG>Example:</STRONG></P>
! 5500: <P>
! 5501: To specify that, in Figures, everything must be drawn in blue on abackground
! 5502: of yellow, the Figure element isgiven these rules:</P>
! 5503: <PRE>
! 5504: Figure :
! 5505: BEGIN
! 5506: Foreground : Blue;
! 5507: Background : Yellow;
! 5508: Fillpattern : backgroundcolor;
! 5509: END;
! 5510: </PRE>
! 5511: <P>
! 5512: and the elements composing figures are given inheritance rules:</P>
! 5513: <PRE>
! 5514: Foreground : Enclosing =;
! 5515: Background : Enclosing =;
! 5516: FillPattern : Enclosing =;
! 5517: </PRE>
! 5518: </BLOCKQUOTE>
! 5519: </DIV>
! 5520:
! 5521: <DIV class="subsection">
! 5522: <H3><A name="content">Presentation box content</A></H3>
! 5523:
! 5524: <P>
! 5525: The <TT>Content</TT> rule applies to presentation boxes. It indicates the
! 5526: content given to a box. This content is either a variable's value or a
! 5527: constant value. In the special case of <A href="#page">header or footer
! 5528: boxes</A>, the content can also be a structured element type.</P>
! 5529: <P>
! 5530: If the content is a constant, it can be specified, as in a variable
! 5531: declaration, either by the name of a constant declared in the <TT>CONST</TT>
! 5532: section or by direct specification of the type and value of the box's
! 5533: content.</P>
! 5534: <P>
! 5535: Similarly, if it is a variable, the name of a variable declared in
! 5536: <TT>VAR</TT> section can be given or the variable may be defined within
! 5537: parentheses. The content inside the parentheses has the same syntax as a <A
! 5538: href="#variables">variable declaration</A>.</P>
! 5539: <P>
! 5540: When the content is a structured element type, the name of the element type is
! 5541: given after the colon. In this case, the box's content is all elements of
! 5542: the named type which are designated by references which are part of the page
! 5543: on which the header or footer with this <TT>Content</TT> rule appears. Only
! 5544: associated elements can appear in a <TT>Content</TT> rule and the structure
! 5545: must provide references to these elements. Moreover, the box whose content
! 5546: they are must be a header or footer box generated by a page box of the primary
! 5547: view.</P>
! 5548: <PRE>
! 5549: 'Content' ':' VarConst
! 5550: VarConst = ConstID / ConstType ConstValue /
! 5551: VarID / '(' FunctionSeq ')' /
! 5552: ElemID .
! 5553: </PRE>
! 5554: <P>
! 5555: A presentation box can have only one <TT>Content</TT> rule, which means that
! 5556: the content of a presentation box cannot vary from view to view. However, such
! 5557: an effect can be achieved by creating several presentation boxes, each with
! 5558: different content and visible in different views.</P>
! 5559: <P>
! 5560: The <TT>Content</TT> rule also applies to elements defined as references in
! 5561: the structure schema. In this case, the content defined by the rule must be
! 5562: a constant. It is this content which appears on the screen or paper to
! 5563: represent references of the type to which the rule applies. A reference can
! 5564: have a <TT>Content</TT> rule or a <A href="#copyrule"><TT>Copy</TT> rule</A>
! 5565: for each view. If neither of these rules appears, the reference is displayed
! 5566: as <TT>[*]</TT>, which is equivalent to the rule:</P>
! 5567: <PRE>
! 5568: Content: Text '[*]';
! 5569: </PRE>
! 5570: <BLOCKQUOTE class="example">
! 5571: <P>
! 5572: <STRONG>Example:</STRONG></P>
! 5573: <P>
! 5574: The content of the presentation box created to make the chapternumber and
! 5575: section number appear before each section title can bedefined by:</P>
! 5576: <PRE>
! 5577: BOXES
! 5578: SectionNumBox :
! 5579: BEGIN
! 5580: Content : NumSection;
! 5581: ...
! 5582: END;
! 5583: </PRE>
! 5584: <P>
! 5585: if the <TT>NumSection</TT>variable has been defined in the variabledefinition
! 5586: section of the presentation schema. Otherwise the<TT>Content</TT>would be
! 5587: written:</P>
! 5588: <PRE>
! 5589: BOXES
! 5590: SectionNumBox :
! 5591: BEGIN
! 5592: Content : (VALUE (ChapterCtr, Roman) TEXT '.'
! 5593: VALUE (SectionCtr, Arabic));
! 5594: ...
! 5595: END;
! 5596: </PRE>
! 5597: <P>
! 5598: To specify that a page footer should contain all elements of the <TT>Note</TT>
! 5599: type are referred to in the page, the following rule is written:</P>
! 5600: <PRE>
! 5601: BOXES
! 5602: NotesFooterBox :
! 5603: BEGIN
! 5604: Content : Note;
! 5605: ...
! 5606: END;
! 5607: </PRE>
! 5608: <P>
! 5609: <TT>Note</TT>is defined as an associated element in the structure schemaand
! 5610: NotesFooterBox is created by a page box of the primary view.</P>
! 5611: </BLOCKQUOTE>
! 5612: </DIV>
! 5613:
! 5614: <DIV class="subsection">
! 5615: <H3><A name="creation">Presentation box creation</A></H3>
! 5616:
! 5617: <P>
! 5618: A creation rule specifies that a presentation box should be created when an
! 5619: element of the type to which the rule is attached appears in the document.</P>
! 5620: <P>
! 5621: A keyword specifies the position, relative to the creating box, at which the
! 5622: created box will be placed in the structure:</P>
! 5623: <DL>
! 5624: <DT><TT>CreateFirst</TT></DT>
! 5625: <DD>specifies that the box should be created asthe first box of the next lower
! 5626: level, before any already existingboxes, and only if the beginning of the
! 5627: creating element is visible;
! 5628: </DD>
! 5629: <DT><TT>CreateLast</TT></DT>
! 5630: <DD>specifies that the box should be created asthe last box of the next lower
! 5631: level, after any existing boxes, andonly if the end of the creating element is
! 5632: visible;
! 5633: </DD>
! 5634: <DT><TT>CreateBefore</TT></DT>
! 5635: <DD>specifies that the box should be createdbefore the creating box, on the
! 5636: same level as the creating box, andonly if the beginning of the creating
! 5637: element is visible;
! 5638: </DD>
! 5639: <DT><TT>CreateAfter</TT></DT>
! 5640: <DD>specifies that the box should be createdafter the creating box, on the
! 5641: same level as the creating box, andonly if the beginning of the creating
! 5642: element is visible;
! 5643: </DD>
! 5644: <DT><TT>CreateEnclosing</TT></DT>
! 5645: <DD>specifies that the box should be createdat the upper level relatively to
! 5646: the creating box, and that it mustcontain that creating box and all
! 5647: presentation boxes created by thesame creating box.
! 5648: </DD>
! 5649: </DL>
! 5650: <P>
! 5651: This keyword can be followed by the <TT>Repeated</TT> keyword to indicate that
! 5652: the box must be created for each part of the creating element. These parts
! 5653: result from the division of the element by page breaks or column changes. If
! 5654: the <TT>Repeated</TT> keyword is missing, the box is only created for the
! 5655: first part of the creating element (<TT>CreateFirst</TT> and
! 5656: <TT>CreateBefore</TT> rules) or for the last part (<TT>CreateLast</TT> and
! 5657: <TT>CreateAfter</TT> rules).</P>
! 5658: <P>
! 5659: The type of presentation to be created is specified at the end of the rule
! 5660: between parentheses.</P>
! 5661: <P>
! 5662: Creation rules cannot appear in the <A href="#defaultpresrules">default
! 5663: presentation rules</A>. The boxes being created should have a
! 5664: <TT>Content</TT> rule which indicates their <A
! 5665: href="#content">content</A>.</P>
! 5666: <P>
! 5667: Creation rules can only appear in the block of rules for the primary view;
! 5668: creation is provoked by a document element for all views. However, for each
! 5669: view, the presentation box is only created if the creating element is itself a
! 5670: box in the view. Moreover, the visibility parameter of the presentation box
! 5671: can be adjusted to control the creation of the box on a view-by-view
! 5672: basis.</P>
! 5673: <PRE>
! 5674: Creation '(' BoxID ')'
! 5675: Creation = Create [ 'Repeated' ] .
! 5676: Create ='CreateFirst' / 'CreateLast' /
! 5677: 'CreateBefore' / 'CreateAfter' /
! 5678: 'CreateEnclosing' .
! 5679: </PRE>
! 5680: <BLOCKQUOTE class="example">
! 5681: <P>
! 5682: <STRONG>Example:</STRONG></P>
! 5683: <P>
! 5684: Let us define an object type, called Table, which is composed of asequence of
! 5685: columns, all having the same fixed width, where thecolumns are separated by
! 5686: vertical lines. There is a line to the leftof the first column and one to the
! 5687: right of the last. Each column hasa variable number of cells, placed one on
! 5688: top of the other andseparated by horizontal lines. There are no horizontal
! 5689: lines abovethe first cell or below the last cell. The text contained in
! 5690: eachcell is broken into lines and these lines are centered horizontallyin the
! 5691: cell. The logical structure of this object is defined by:</P>
! 5692: <PRE>
! 5693: Table = LIST OF (Column);
! 5694: Column = LIST OF (Cell = Text);
! 5695: </PRE>
! 5696:
! 5697: <DIV class="figure">
! 5698: <HR>
! 5699: <PRE>
! 5700: | | | |
! 5701: | xx xxxx xxxx |x xxxx xxx xxxxx| x xxx x xxx |
! 5702: | xxx xxx xxxx x | x xx x xxx | xxxxx xxxx xx |
! 5703: | xxxxx xxxx |----------------| xxx xxxxx x |
! 5704: | xxxxx xxx xxxx | xxxx xx xx xxx | xx xx |
! 5705: | xxx xxxx x xxx | xxxx x xxx x |---------------|
! 5706: |----------------| xxx xxxx xxxxx | xxxxx xxxxx |
! 5707: | xxx xxx xxxxxx |----------------| xxx xxxx xxxx |
! 5708: | xxxx xxxx xx | xxxx xx x xx | xxx xx x xx |
! 5709: |----------------| xxx xxxxx xxxx | xxxx xxxx xxx |
! 5710: | xxxxx xxx xxxx | xxxx xx x xx | xxxxx xxx |
! 5711: |xxxx xx x xxxxxx| xxxx xx xxxxxx | xxxxx xxxxx |
! 5712: </PRE>
! 5713: <P align=center>
! 5714: <EM><A name="table">The design of a table</A></EM></P>
! 5715: <HR>
! 5716: </DIV>
! 5717: <P>
! 5718: The presentation of the table should resemble the design of the above <A
! 5719: href="#table">figure</A>. It is defined by the following presentation schema
! 5720: fragment:</P>
! 5721: <PRE>
! 5722: BOXES
! 5723: VertLine : BEGIN
! 5724: Width : 0.3 cm;
! 5725: Height : Enclosing . Height;
! 5726: VertPos : Top = Enclosing . Top;
! 5727: HorizPos : Left = Previous . Right;
! 5728: Content : Graphics 'v';
! 5729: END;
! 5730:
! 5731: HorizLine: BEGIN
! 5732: Width : Enclosing . Width;
! 5733: Height : 0.3 cm;
! 5734: VertPos : Top = Previous . Bottom;
! 5735: HorizPos : Left = Enclosing . Left;
! 5736: Content : Graphics 'h';
! 5737: END;
! 5738:
! 5739: RULES
! 5740: Column : BEGIN
! 5741: CreateBefore (VertLine);
! 5742: IF LAST CreateAfter (VertLine);
! 5743: Width : 2.8 cm;
! 5744: Height : Enclosed . Height;
! 5745: VertPos : Top = Enclosing . Top;
! 5746: HorizPos : Left = Previous . Right;
! 5747: END;
! 5748:
! 5749: Cell : BEGIN
! 5750: IF NOT FIRST CreateBefore (HorizLine);
! 5751: Width : Enclosing . Width;
! 5752: Height : Enclosed . Height;
! 5753: VertPos : Top = Previous . Bottom;
! 5754: HorizPos : Left = Enclosing . Left;
! 5755: Line;
! 5756: Adjust : VMiddle;
! 5757: END;
! 5758: </PRE>
! 5759: <P>
! 5760: It is useful to note that the horizontal position rule of the first vertical
! 5761: line will not be applied, since there is no preceding box. In this case, the
! 5762: box is simply placed on the left side of the enclosing box.</P>
! 5763: </BLOCKQUOTE>
! 5764: </DIV>
! 5765:
! 5766: <DIV class="subsection">
! 5767: <H3><A name="page">Page layout</A></H3>
! 5768:
! 5769: <P>
! 5770: The page models specified in the <TT>Page</TT> rule are defined by boxes
! 5771: declared in the <TT>BOXES</TT> section of the presentation schema. Pages are
! 5772: not described as frames which will be filled by the document's text, but as
! 5773: element are inserted in the flow of the document and which mark the page
! 5774: breaks. Each of these page break elements contains presentation boxes which
! 5775: represent the footer boxes of a page followed by header boxes of the next
! 5776: page. The page box itself is the simple line which separates two pages on the
! 5777: screen. Both the footer and header boxes placed themselves with respect to
! 5778: this page box, with the footer being placed above it and the header boxes
! 5779: being placed above it.</P>
! 5780: <P>
! 5781: The boxes created by a page box are headers and footers and can only place
! 5782: themselves vertically with respect to the page box itself (which is in fact
! 5783: the separation between two pages). Besides, it is their vertical position
! 5784: rule which determines whether they are header or footer boxes. Header and
! 5785: footer boxes must have an explicit vertical position rule (they must not use
! 5786: the default rule).</P>
! 5787: <P>
! 5788: Footer boxes must have an absolute height or inherit the height of their
! 5789: contents:</P>
! 5790: <PRE>
! 5791: Height : Enclosed . Height;
! 5792: </PRE>
! 5793: <P>
! 5794: A page box must have height and width rules and these two rules must be
! 5795: specified with constant values, expressed in centimeters, inches, or
! 5796: typographer's points. These two rules are interpreted in a special way for
! 5797: page boxes: they determine the width of the page and the vertical distance
! 5798: between two page separators, which is the height of the page and its header
! 5799: and footer together.</P>
! 5800: <P>
! 5801: A page box should also have vertical and horizontal position rules and these
! 5802: two rules should specify the position on the sheet of paper of the rectangle
! 5803: enclosing the page's contents. These two rules must position the upper left
! 5804: corner of the enclosing rectangle in relation to the upper left corner of the
! 5805: sheet of paper, considered to be the enclosing element. In both rules,
! 5806: distances must be expressed in fixed units: centimeters (<TT>cm</TT>), inches
! 5807: (<TT>in</TT>), or typographer's points (<TT>pt</TT>). Thus, rules similar to
! 5808: the following should be found in the rules for a page box:</P>
! 5809: <PRE>
! 5810: BOXES
! 5811: ThePage :
! 5812: BEGIN
! 5813: VertPos : Top = Enclosing . Top + 3 cm;
! 5814: HorizPos : Left = Enclosing . Left + 2.5 cm;
! 5815: Width : 16 cm;
! 5816: Height : 22.5 cm;
! 5817: END;
! 5818: </PRE>
! 5819: <P>
! 5820: When a document must be page broken, the page models to be constructed are
! 5821: defined in the <TT>BOXES</TT> section of the presentation schema by declaring
! 5822: page boxes and header and footer boxes. Also, the <TT>Page</TT> rule is used
! 5823: to specify to which parts of the document and to which views each model should
! 5824: be applied.</P>
! 5825: <P>
! 5826: The <TT>Page</TT> rule has only one parameter, given between parentheses after
! 5827: the <TT>Page</TT> keyword. This parameter is the name of the box which must
! 5828: serve as the model for page construction. When a <TT>Page</TT> rule is
! 5829: attached to an element type, each time such an element appears in a document,
! 5830: a page break takes place and the page model indicated in the rule is applied
! 5831: to all following pages, until reaching the next element which has a
! 5832: <TT>Page</TT> rule.</P>
! 5833: <P>
! 5834: The <TT>Page</TT> rule applies to only one view; if it appears in the primary
! 5835: view's block of rules, a <TT>Page</TT> rule applies only to that view. Thus,
! 5836: different page models can be defined for the full document and for its table
! 5837: of contents, which is another view of the same document. Some views can be
! 5838: specified with pages, and other views of the same document can be specified
! 5839: without pages.</P>
! 5840: <PRE>
! 5841: 'Page' '(' BoxID ')'
! 5842: </PRE>
! 5843: </DIV>
! 5844:
! 5845: <DIV class="subsection">
! 5846: <H3><A name="copyrule">Box copies</A></H3>
! 5847:
! 5848: <P>
! 5849: The <TT>Copy</TT> rule can be used for an element which is defined as a
! 5850: reference in the structure schema. In this case, the rule specified, between
! 5851: parenthesis, thee name of the box (declared in the <TT>BOXES</TT> section)
! 5852: which must be produced when this reference appears in the structure of a
! 5853: document. The box produced is a copy (same contents, but possible different
! 5854: presentation) of the box type indicated by the parameter between parentheses,
! 5855: and which is in the element designated by the reference. The name of a box
! 5856: can be replaced by type name. Then what is copied is the contents of the
! 5857: element of this type which is inside the referenced element.</P>
! 5858: <P>
! 5859: Whether a box name or type name is given, it may be followed by the name of a
! 5860: structure schema between parentheses. This signifies that the box or type is
! 5861: defined in the indicated structure schema and not in the structure schema with
! 5862: which the rule's presentation schema is associated.</P>
! 5863: <P>
! 5864: The <TT>Copy</TT> rule can also be applied to a presentation box. If the
! 5865: presentation box was created by a reference attribute, the rule is applied as
! 5866: in the case of a reference element: the contents of the box having the
! 5867: <TT>Copy</TT> rule are based on the element designated by the reference
! 5868: attribute. For other presentation boxes, the <TT>Copy</TT> rule takes a type
! 5869: name parameter which can be followed, between parentheses, by the name of the
! 5870: structure schema in which the type is defined, if it is not defined in the
! 5871: same schema. The contents of the box which has this rule are a copy of the
! 5872: element of this type which is in the element creating the presentation box, or
! 5873: by default, the box of this type which precedes the presentation box. This
! 5874: last facility is used, for example, to define the running titles in headers or
! 5875: footers.</P>
! 5876: <PRE>
! 5877: 'Copy' '(' BoxTypeToCopy ')' .
! 5878: BoxTypeToCopy = BoxID [ ExtStruct ] /
! 5879: ElemID [ ExtStruct ] .
! 5880: ExtStruct = '(' ElemID ')' .
! 5881: </PRE>
! 5882: <P>
! 5883: Like the creation rules, the <TT>Copy</TT> rule cannot appear in the <A
! 5884: href="#defaultpresrules">default presentation rules</A>. Moreover, this rule
! 5885: can only appear in the primary view's block of rules; the copy rule is applied
! 5886: to all views.</P>
! 5887: <BLOCKQUOTE class="example">
! 5888: <P>
! 5889: <STRONG>Example:</STRONG></P>
! 5890: <P>
! 5891: If the following definitions are in the structure schema:</P>
! 5892: <PRE>
! 5893: Body = LIST OF (Chapter =
! 5894: BEGIN
! 5895: ChapterTitle = Text;
! 5896: ChapterBody = SectionSeq;
! 5897: END);
! 5898: RefChapter = REFERENCE (Chapter);
! 5899: </PRE>
! 5900: <P>
! 5901: then the following presentation rules (among many other rules in
! 5902: thepresentation schema) can be specified:</P>
! 5903: <PRE>
! 5904: COUNTERS
! 5905: ChapterCtr : RANK OF Chapter;
! 5906: BOXES
! 5907: ChapterNumber :
! 5908: BEGIN
! 5909: Content : (VALUE (ChapterCtr, URoman));
! 5910: ...
! 5911: END;
! 5912: RULES
! 5913: Chapter :
! 5914: BEGIN
! 5915: CreateFirst (ChapterNumber);
! 5916: ...
! 5917: END;
! 5918: RefChapter :
! 5919: BEGIN
! 5920: Copy (ChapterNumber);
! 5921: ...
! 5922: END;
! 5923: </PRE>
! 5924: <P>
! 5925: which makes the number of the chapter designated by the referenceappear in
! 5926: uppercase roman numerals, in place of the reference to achapter itself.
! 5927: Alternatively, the chapter title can be made toappear in place of the
! 5928: reference by writing this <TT>Copy</TT>rule:</P>
! 5929: <PRE>
! 5930: Copy (ChapterTitle);
! 5931: </PRE>
! 5932: <P>
! 5933: To define a header box, named <TT>RunningTitle</TT>, which contains the title
! 5934: of the current chapter, the box's contents are defined in this way:</P>
! 5935: <PRE>
! 5936: BOXES
! 5937: RunningTitle :
! 5938: Copy (ChapterTitle);
! 5939: </PRE>
! 5940: </BLOCKQUOTE>
! 5941: </DIV>
! 5942: </DIV>
! 5943: <HR>
! 5944: </DIV>
! 5945:
! 5946: <DIV class="chapter">
! 5947: <H1>The T language</H1>
! 5948:
! 5949:
! 5950: <DIV class="section">
! 5951: <H2>Document translation</H2>
! 5952:
! 5953: <P>
! 5954: Because of its document model, Thot can produce documents in a high-level
! 5955: abstract form. This form, called the <EM>canonical form</EM> is specific to
! 5956: Thot; it is well suited to the editor's manipulations, but it does not
! 5957: necessarily suit other operations which might be applied to documents. Because
! 5958: of this, the Thot editor offers the choice of saving documents in its own form
! 5959: (the canonical form) or a format defined by the user. In the latter case, the
! 5960: Thot document is transformed by the translation program. This facility can
! 5961: also be used to export documents from Thot to systems using other
! 5962: formalisms.</P>
! 5963:
! 5964: <DIV class="subsection">
! 5965: <H3>Translation principles</H3>
! 5966:
! 5967: <P>
! 5968: Document translation allows the export of documents to other systems which do
! 5969: not accept Thot's canonical form. Translation can be used to export document
! 5970: to source-based formatters like T<SUB><BIG>E</BIG></SUB>X,
! 5971: L<SUP>A</SUP>T<SUB><BIG>E</BIG></SUB>X, and <TT>troff</TT>. It can also be
! 5972: used to translate documents into interchange formats like SGML or HTML. To
! 5973: allow the widest range of possible exports, Thot does not limit the choice of
! 5974: translations, but rather allows the user to define the formalisms into which
! 5975: documents can be translated.</P>
! 5976: <P>
! 5977: For each document or object class, a set of translation rules can be defined,
! 5978: specifying how the canonical form should be transformed into a given
! 5979: formalism. These translation rules are grouped into <EM>translation
! 5980: schemas</EM>, each schema containing the rules necessary to translate a
! 5981: generic logical structure (document or object structure) into a particular
! 5982: formalism. The same generic logical structure can have several different
! 5983: translation schemas, each defining translation rules for a different
! 5984: formalism.</P>
! 5985: <P>
! 5986: Like presentation schemas, translation schemas are generic. Thus, they apply
! 5987: to an entire object or document class and permit translation of all documents
! 5988: or objects of that class.</P>
! 5989: </DIV>
! 5990:
! 5991: <DIV class="subsection">
! 5992: <H3>Translation procedure</H3>
! 5993:
! 5994: <P>
! 5995: The translator works on the specific logical structure of the document being
! 5996: translated. It traverses the primary tree of this logical structure in
! 5997: pre-order and, at each node encountered, it applies the corresponding
! 5998: translation rules defined in the translation schema. Translation can be
! 5999: associated:</P>
! 6000: <UL>
! 6001: <LI>with element types defined in the structure schema,
! 6002: <LI>with global or local attributes defined in the structure schema,
! 6003: <LI>with specific presentation rules,
! 6004: <LI>with the content of the leaves of the structure (characters,symbols and
! 6005: graphical elements)
! 6006: </UL>
! 6007: <P>
! 6008: Thus, for each node, the translator applies all rules associated with the
! 6009: element type, all rules associated with each attribute (local or global)
! 6010: carried by the element, and if the element is a leaf of the tree, it also
! 6011: applies Translation rules for characters, symbols, or graphical elements,
! 6012: depending on the type of the leaf.</P>
! 6013: <P>
! 6014: Rules associated with the content of leaves are different from all other
! 6015: rules: they specify only how to translate character strings, symbols, and
! 6016: graphical elements. All other rules, whether associated with element types,
! 6017: with specific presentation rules or with attributes, are treated similarly.
! 6018: These rules primarily allow:</P>
! 6019: <UL>
! 6020: <LI>generation of a text constant or variable before or afterthe contents of
! 6021: an element,
! 6022: <LI>modification of the order in which elements appear aftertranslation,
! 6023: <LI>removal of an element in the translated document,
! 6024: <LI>and writing messages on the user's terminal during translation.
! 6025: </UL>
! 6026: </DIV>
! 6027: </DIV>
! 6028:
! 6029: <DIV class="section">
! 6030: <H2>Translation definition language</H2>
! 6031:
! 6032: <P>
! 6033: Translation schemas are written in a custom language, called T, which is
! 6034: described in the rest of this chapter. The grammar of T is specified using
! 6035: the same <A href="#metalang">meta-language</A> as was used for the S and P
! 6036: languages and the translation schemas are written using the same conventions
! 6037: as the structure and presentation schemas. In particular, the keywords of the
! 6038: T language (the stings between apostrophes in the following syntax rules) can
! 6039: be written in any combination of upper-case and lower-case letters, but
! 6040: identifiers created by the programmer must always be written in the same
! 6041: way.</P>
! 6042:
! 6043: <DIV class="subsection">
! 6044: <H3>Organization of a translation schema</H3>
! 6045:
! 6046: <P>
! 6047: A translation schema is begun by the <TT>TRANSLATION</TT> keyword and is
! 6048: terminated by the <TT>END</TT> keyword. The <TT>TRANSLATION</TT> keyword is
! 6049: followed by the name of the generic structure for which a translation is being
! 6050: defined and a semicolon. This name must be identical to the name which
! 6051: appears after the <TT>STRUCTURE</TT> keyword in the corresponding structure
! 6052: schema.</P>
! 6053: <P>
! 6054: After this declaration of the structure, the following material appears in
! 6055: order:</P>
! 6056: <UL>
! 6057: <LI>the length of lines produced by the translation,
! 6058: <LI>the character delimiting the end of the line,
! 6059: <LI>the character string which the translator will insert if it must
! 6060: line-break the translated text,
! 6061: <LI>declarations of
! 6062: <UL>
! 6063: <LI>buffers,
! 6064: <LI>counters,
! 6065: <LI>constants,
! 6066: <LI>variables,
! 6067: </UL>
! 6068: <LI>translation rules associated with element types,
! 6069: <LI>translation rules associated with attributes,
! 6070: <LI>translation rules associated with specific presentation rules,
! 6071: <LI>translation rules associated with characters strings, symbols and
! 6072: graphical elements.
! 6073: </UL>
! 6074: <P>
! 6075: Each of these sections is introduced by a keyword followed by a sequence of
! 6076: declarations. All of these sections are optional, expect for the translation
! 6077: rules associated with element types. Many <TT>TEXTTRANSLATE</TT> sections can
! 6078: appear, each defining the rules for translating character strings of a
! 6079: particular alphabet.</P>
! 6080: <PRE>
! 6081: TransSchema ='TRANSLATION' ElemID ';'
! 6082: [ 'LINELENGTH' LineLength ';' ]
! 6083: [ 'LINEEND' CHARACTER ';' ]
! 6084: [ 'LINEENDINSERT' STRING ';' ]
! 6085: [ 'BUFFERS' BufferSeq ]
! 6086: [ 'COUNTERS' CounterSeq ]
! 6087: [ 'CONST' ConstSeq ]
! 6088: [ 'VAR' VariableSeq ]
! 6089: 'RULES' ElemSeq
! 6090: [ 'ATTRIBUTES' AttrSeq ]
! 6091: [ 'PRESENTATION' PresSeq ]
! 6092: < 'TEXTTRANSLATE' TextTransSeq >
! 6093: [ 'SYMBTRANSLATE' TransSeq ]
! 6094: [ 'GRAPHTRANSLATE' TransSeq ]
! 6095: 'END' .
! 6096: </PRE>
! 6097: </DIV>
! 6098:
! 6099: <DIV class="subsection">
! 6100: <H3><A name="linelength">Line length</A></H3>
! 6101:
! 6102: <P>
! 6103: If a <TT>LINELENGTH</TT> instruction is present after the structure
! 6104: declaration, the translator divides the text it produces into lines, each line
! 6105: having a length less than or equal to the integer which follows the
! 6106: <TT>LINELENGTH</TT> keyword. This maximum line length is expressed as a
! 6107: number of characters. The end of the line is marked by the character defined
! 6108: by the <TT>LINEEND</TT> instruction. When the translator breaks the lines on
! 6109: a space character in generated text, this space will be replaced by the
! 6110: character string defined by the <TT>LINEENDINSERT</TT> instruction.</P>
! 6111: <P>
! 6112: If the <TT>LINEEND</TT> instruction is not defined then the linefeed character
! 6113: (octal code 12) is used as the default line end character. If the
! 6114: <TT>LINEENDINSERT</TT> instruction is not defined, the linefeed character is
! 6115: inserted at the end of the produced lines. If there is no <TT>LINELENGTH</TT>
! 6116: instruction, the translated text is not divided into lines. Otherwise, if the
! 6117: translation rules generate line end marks, these marks remain in the
! 6118: translated text, but the length of the lines is not controlled by the
! 6119: translator.</P>
! 6120: <PRE>
! 6121: LineLength = NUMBER .
! 6122: </PRE>
! 6123: <BLOCKQUOTE class="example">
! 6124: <P>
! 6125: <STRONG>Example:</STRONG></P>
! 6126: <P>
! 6127: To limit the lines produced by the translator to a length of 80characters, the
! 6128: following rule is written at the beginning of thetranslation schema.</P>
! 6129: <PRE>
! 6130: LineLength 80;
! 6131: </PRE>
! 6132: </BLOCKQUOTE>
! 6133: </DIV>
! 6134:
! 6135: <DIV class="subsection">
! 6136: <H3>Buffers</H3>
! 6137:
! 6138: <P>
! 6139: A buffer is a unit of memory managed by the translator, which can either
! 6140: contain text read from the terminal during the translation (see the <A
! 6141: href="#readrule"><TT>Read</TT> rule</A>), or the name of the last image
! 6142: (bit-map) encountered by the translator in its traversal of the document.
! 6143: Remember the images are stored in files that are separate for the document
! 6144: files and that the canonical form contains only the names of the files in
! 6145: which the images are found.</P>
! 6146: <P>
! 6147: Thus, there are two types of buffers: buffers for reading from the terminal
! 6148: (filled by the <TT>Read</TT> rule) and the buffer of image names (containing
! 6149: the name of the last image encountered). A translation schema can use either
! 6150: type, one or several read buffers and one (and only one) image name
! 6151: buffer.</P>
! 6152: <P>
! 6153: If any buffers are used, the <TT>BUFFERS</TT> keyword must be present,
! 6154: followed by declarations of every buffer used in the translation schema. Each
! 6155: buffer declaration is composed only of the name of the buffer, chosen freely
! 6156: by the programmer. The image name buffer is identified by the
! 6157: <TT>Picture</TT> keyword, between parentheses, following the buffer name. The
! 6158: <TT>Picture</TT> keyword may only appear once. Each buffer declaration is
! 6159: terminated by a semicolon.</P>
! 6160: <PRE>
! 6161: BufferSeq = Buffer < Buffer > .
! 6162: Buffer = BufferID [ '(' 'Picture' ')' ] ';' .
! 6163: BufferID = NAME .
! 6164: </PRE>
! 6165: <BLOCKQUOTE class="example">
! 6166: <P>
! 6167: <STRONG>Example:</STRONG></P>
! 6168: <P>
! 6169: The following buffer declarations create an image name buffer
! 6170: named<TT>ImageName</TT>and a read buffer named<A
! 6171: name="destname"><TT>DestName</TT></A>:</P>
! 6172: <PRE>
! 6173: BUFFERS
! 6174: ImageName (Picture); DestName;
! 6175: </PRE>
! 6176: </BLOCKQUOTE>
! 6177: </DIV>
! 6178:
! 6179: <DIV class="subsection">
! 6180: <H3><A name="counters">Counters</A></H3>
! 6181:
! 6182: <P>
! 6183: Certain translation rules generate text that varies according to the context
! 6184: of the element to which the rules apply. Variable text is defined either in
! 6185: the <A href="#varsect"><TT>VAR</TT> section</A> of the translation schema or
! 6186: in the rule itself (see the <TT>Create</TT> and <TT>Write</TT> rules). Both
! 6187: types of definition rely on counters for the calculation of variable
! 6188: material.</P>
! 6189: <P>
! 6190: There are two types of counter: counters whose value is explicitely computed
! 6191: by applying <A href="#setandadd"><TT>Set</TT> and <TT>Add</TT> rules</A>, and
! 6192: counters whose value is computed by a function associated with the counter.
! 6193: Those functions allow the same calculations as can be used in presentation
! 6194: schemas. As in a presentation schema, counters must be defined in the
! 6195: <TT>COUNTERS</TT> section of the translation schema before they are used.</P>
! 6196: <P>
! 6197: When counters are used in a translation schema, the <TT>COUNTERS</TT> keyword
! 6198: is followed by the declarations of every counter used. Each declaration is
! 6199: composed of the counter's name possibly followed by a colon and the counting
! 6200: function to be used for the counter. The declaration is terminated by a
! 6201: semi-colon. If the counter is explicitely computed by <TT>Set</TT> and
! 6202: <TT>Add</TT> rules, no counting function is indicated. If a counting function
! 6203: is indicated, <TT>Set</TT> and <TT>Add</TT> rules cannot be applied to that
! 6204: counter.</P>
! 6205: <P>
! 6206: The counting function indicates how the counter's value will be computed.
! 6207: Three functions are available: <TT>Rank</TT>, <TT>Rlevel</TT>, and
! 6208: <TT>Set</TT>.</P>
! 6209: <UL>
! 6210: <LI><TT>Rank of ElemID</TT>indicates that the counter's value is the rank
! 6211: ofthe element of type <TT>ElemID</TT>which encloses the element for whichthe
! 6212: counter is being evaluated. For the purposes of this function, anelement of
! 6213: type <TT>ElemID</TT>is considered to enclose itself. Thisfunction is
! 6214: primarily used when the element of type <TT>ElemID</TT>ispart of an aggregate
! 6215: or list, in which case the counter's value is theelement's rank in its list or
! 6216: aggregate. Note that, unlike the<TT>Rank</TT>function for presentation
! 6217: schemas, the <TT>Page</TT>keyword cannotbe used in place of the
! 6218: <TT>ElemID</TT>.
! 6219: <P>
! 6220: The type name <TT>ElemID</TT> can be followed by an integer. That number
! 6221: represents the relative level, among the ancestors of the concerned element,
! 6222: of the element whose rank is asked. If that relative level <I>n</I> is
! 6223: unsigned, the $n^th$ element of type <TT>ElemID</TT> encountered when
! 6224: travelling the logical structure from the root to the concerned element is
! 6225: taken into account. If the relative level is negative, the logical structure
! 6226: is travelled in the other direction, from the concerned element to the
! 6227: root.</P>
! 6228: <LI><TT>Rlevel of ElemID</TT>indicates that the counter's values is
! 6229: therelative level in the tree of the element for which the counter isbeing
! 6230: evaluated. The counter counts the number of elements of
! 6231: type<TT>ElemID</TT>which are found on the path between the root of
! 6232: thedocument's logical structure tree and the element (inclusive).
! 6233: <LI><TT>Set n on Type1 Add m on Type2</TT>indicates that the counter's valueis
! 6234: calculated as follows: in traversing the document from thebeginning to the
! 6235: element for which the counter is being evaluated, thecounter is set to the
! 6236: value <TT>n</TT>each time a <TT>Type1</TT>element isencountered and is
! 6237: incremented by the amount <TT>m</TT>each time a<TT>Type2</TT>element is
! 6238: encountered. The initial value <TT>n</TT>and theincrement <TT>m</TT>are
! 6239: integers.
! 6240: </UL>
! 6241: <P>
! 6242: As in a presentation schema, the <TT>Rank</TT> and <TT>Set</TT> functions can
! 6243: be modified by a numeric attribute which changes their initial value. This is
! 6244: indicated by the <TT>Init</TT> keyword followed by the numeric attribute's
! 6245: name. The <TT>Set</TT> function takes the value of the attribute instead of
! 6246: the <TT>InitValue</TT> (<TT>n</TT>). For the <TT>Rank</TT> function, the
! 6247: value of the attribute is considered to be the rank of the first element of
! 6248: the list (rather than the normal value of 1). Subsequent items in the list
! 6249: have their ranks shifted accordingly. In both cases, the attribute must be
! 6250: numeric and must be a local attribute of the root of the document itself.</P>
! 6251: <PRE>
! 6252: CounterSeq = Counter < Counter > .
! 6253: Counter = CounterID [ ':' CounterFunc ] ';' .
! 6254: CounterID = NAME .
! 6255: CounterFunc = 'Rank' 'of' ElemID [ SLevelAsc ]
! 6256: [ 'Init' AttrID ] /
! 6257: 'Rlevel' 'of' ElemID /
! 6258: 'Set' InitValue 'On' ElemID
! 6259: 'Add' Increment 'On' ElemID
! 6260: [ 'Init' AttrID ] .
! 6261: SLevelAsc = [ '-' ] LevelAsc .
! 6262: LevelAsc = NUMBER .
! 6263: InitValue = NUMBER .
! 6264: Increment = NUMBER .
! 6265: ElemID = NAME .
! 6266: AttrID = NAME .
! 6267: </PRE>
! 6268: <BLOCKQUOTE class="example">
! 6269: <P>
! 6270: <STRONG>Example:</STRONG></P>
! 6271: <P>
! 6272: If the body of a chapter is defined in the structure schema by:</P>
! 6273: <PRE>
! 6274: Chapter_Body = LIST OF
! 6275: (Section = BEGIN
! 6276: Section_Title = Text;
! 6277: Section_Body = BEGIN
! 6278: Paragraphs;
! 6279: Section;
! 6280: END;
! 6281: END
! 6282: );
! 6283: </PRE>
! 6284: <P>
! 6285: (sections are defined recursively), a counter can be defined givingthe <A
! 6286: name="sectnum">number of a section</A>within its level in thehierarchy:</P>
! 6287: <PRE>
! 6288: COUNTERS
! 6289: SectionNumber : Rank of Section;
! 6290: </PRE>
! 6291: <P>
! 6292: A counter holding the hierarchic level of a section:</P>
! 6293: <PRE>
! 6294: SectionLevel : Rlevel of Section;
! 6295: </PRE>
! 6296: <P>
! 6297: A <A name="uniquenum">counter</A>which sequentially numbers all thedocument's
! 6298: sections, whatever their hierarchic level:</P>
! 6299: <PRE>
! 6300: UniqueSectNum : Set 0 on Document Add 1 on Section;
! 6301: </PRE>
! 6302: </BLOCKQUOTE>
! 6303: </DIV>
! 6304:
! 6305: <DIV class="subsection">
! 6306: <H3>Constants</H3>
! 6307:
! 6308: <P>
! 6309: A common feature of translation rules is the generation of constant text. This
! 6310: text can be defined in the rule that generates it (see for example the <A
! 6311: href="#create"><TT>Create</TT></A> and <A href="#writerule"><TT>Write</TT></A>
! 6312: rules); but it can also be defined once in the constant declaration section
! 6313: and used many times in different rules. The latter option is preferable when
! 6314: the same text is used in several rules or several <A
! 6315: href="#varsect">variables</A>.</P>
! 6316: <P>
! 6317: The <TT>CONST</TT> keyword begins the constant declaration section of the
! 6318: translation schema. It must be omitted if no constants are declared. Each
! 6319: constant declaration is composed of the constant name, an equals sign, and the
! 6320: constant's value, which is a character string between apostrophes. A constant
! 6321: declaration is terminated by a semicolon.</P>
! 6322: <PRE>
! 6323: ConstSeq = Const < Const > .
! 6324: Const = ConstID '=' ConstValue ';' .
! 6325: ConstID = NAME .
! 6326: ConstValue = STRING .
! 6327: </PRE>
! 6328: <BLOCKQUOTE class="example">
! 6329: <P>
! 6330: <STRONG><A name="levelexample">Example:</A></STRONG></P>
! 6331: <P>
! 6332: The following rule assigns the name <TT>TxtLevel</TT>to the characterstring
! 6333: ``Level'':</P>
! 6334: <PRE>
! 6335: CONST
! 6336: TxtLevel = 'Level';
! 6337: </PRE>
! 6338: </BLOCKQUOTE>
! 6339: </DIV>
! 6340:
! 6341: <DIV class="subsection">
! 6342: <H3><A name="varsect">Variables</A></H3>
! 6343:
! 6344: <P>
! 6345: Variables allow to define file names or variable text which is generated by
! 6346: the <TT>Create</TT> and <TT>Write</TT> rules. Variables can be defined either
! 6347: in the <TT>VAR</TT> section of the translation schema or directly in the rules
! 6348: which use them. Variables that define fine names must be declared in the
! 6349: <TT>VAR</TT> section, and when the same variable is used several times in the
! 6350: translation schema, it makes sense to define it globally in the <TT>VAR</TT>
! 6351: section. This section is only present if at least one variable is defined
! 6352: globally.</P>
! 6353: <P>
! 6354: After the <TT>VAR</TT> keyword, each global variable is defined by its name, a
! 6355: colon separator and a sequence of functions (at least one function). Each
! 6356: variable definition is terminated by a semicolon. Functions determine the
! 6357: different parts which together give the value of the variable. The value is
! 6358: obtained by concatenating the strings produced by each of the functions. Seven
! 6359: types of functions are available. Each variable definition may use any number
! 6360: of functions of each type.</P>
! 6361: <UL>
! 6362: <LI>The function <TT>Value(Counter)</TT>returns a string representing thevalue
! 6363: taken by the counter when it is evaluated for the element inwhose rule the
! 6364: variable is used. The counter must have been declaredin the
! 6365: <TT>COUNTERS</TT>section of the translation schema. When thecounter is
! 6366: expressed in arabic numerals, the countername can be followed by a colon and
! 6367: an integer indicating a minimumlength (number of characters) for the string;
! 6368: if the counter's valueis normally expressed with fewer characters than the
! 6369: required minimum,zeroes are added to the front of the string to achieve the
! 6370: minimumlength.
! 6371: <P>
! 6372: By default, the counter value is written in arabic digits. If another
! 6373: representation of that value is needed, the counter name must be followed by a
! 6374: comma and one of the following keywords:</P>
! 6375: <UL>
! 6376: <LI><TT>Arabic</TT>: arabic numerals (default value),
! 6377: <LI><TT>LRoman</TT>: lower-case roman numerals,
! 6378: <LI><TT>URoman</TT>: upper-case roman numerals,
! 6379: <LI><TT>Uppercase</TT>: upper-case letter,
! 6380: <LI><TT>Lowercase</TT>: lower-case letter.
! 6381: </UL>
! 6382: <LI>The function <TT>FileDir</TT>, without parameter, returns a
! 6383: stringrepresenting the name of the directory of the output file that has
! 6384: beengiven as a parameter to the translation program. The string includesa
! 6385: character '/' at the end.
! 6386: <LI>The function <TT>FileName</TT>, without parameter, returns a
! 6387: stringrepresenting the name of the output file that has been given as
! 6388: aparameter to the translation program. The file extension (the characterstring
! 6389: that terminate the file name, after a dot) is not part ofthat string.
! 6390: <LI>The function <TT>Extension</TT>, without parameter, returns a
! 6391: stringrepresenting the extension of the file name. That string is emptyif the
! 6392: file name that has been given as a parameter to the translationprogram has no
! 6393: extension. If there is an extension, its firstcharacter is a dot.
! 6394: <LI>The function <TT>DocumentName</TT>, without parameter, returns a
! 6395: stringrepresenting the name of the document being translated.
! 6396: <LI>The function <TT>DocumentDir</TT>, without parameter, returns a
! 6397: stringrepresenting the directory containing the document being translated.
! 6398: <LI>The function formed by the name of a constant returns thatconstant's
! 6399: value.
! 6400: <LI>The function formed by a character string between apostrophes returnsthat
! 6401: string.
! 6402: <LI>The function formed by the name of a buffer returns the contents ofthat
! 6403: buffer. If the named buffer is the image buffer, then the nameof the last
! 6404: image encountered is returned. Otherwise, the buffer is a read bufferand the
! 6405: value returned is text previously read from the terminal. Ifthe buffer is
! 6406: empty (no image has been encountered or the <TT>Read</TT>rule has not been
! 6407: executed for the buffer), then the empty string isreturned.
! 6408: <LI>The function formed by an attribute name takes the value of theindicated
! 6409: attribute for the element to which the variable applies. Ifthe element does
! 6410: not have that attribute, then the element's ancestorare searched toward the
! 6411: root of the tree. If one of the ancestorsdoes have the attribute then its
! 6412: value is used. If no ancestors havethe attribute, then the value of the
! 6413: function is the empty string.
! 6414: </UL>
! 6415: <PRE>
! 6416: VariableSeq = Variable < Variable > .
! 6417: Variable = VarID ':' Function < Function > ';' .
! 6418: VarID = NAME .
! 6419: Function ='Value' '(' CounterID [ ':' Length ]
! 6420: [ ',' CounterStyle ] ')' /
! 6421: 'FileDir' / 'FileName' / 'Extension' /
! 6422: 'DocumentName' / 'DocumentDir' /
! 6423: ConstID / CharString /
! 6424: BufferID / AttrID .
! 6425: Length = NUMBER .
! 6426: CounterStyle= 'Arabic' / 'LRoman' / 'URoman' /
! 6427: 'Uppercase' / 'Lowercase' .
! 6428: CharString = STRING .
! 6429: </PRE>
! 6430: <BLOCKQUOTE class="example">
! 6431: <P>
! 6432: <STRONG>Example:</STRONG></P>
! 6433: <P>
! 6434: To create, at the beginning of each section of the translateddocument, text
! 6435: composed of the string ``Section'' followed by thesection number, the
! 6436: following <A name="varsectexample">variable definition</A>might be used:</P>
! 6437: <PRE>
! 6438: VAR
! 6439: SectionVar : 'Section' Value(SectionNumber);
! 6440: </PRE>
! 6441: <P>
! 6442: (see the definition of <A href="#sectnum"><TT>SectionNumber</TT></A>).</P>
! 6443: <P>
! 6444: The following variable definition can be used to create, at the beginning of
! 6445: each section, the text ``Level'' followed by the hierarchical level of the
! 6446: section. It used the constant defined above.</P>
! 6447: <PRE>
! 6448: LevelVar : TxtLevel Value(SectionLevel);
! 6449: </PRE>
! 6450: <P>
! 6451: (see the definitions of <A href="#sectnum"><TT>SectionLevel</TT></A>and of <A
! 6452: href="#levelexample"><TT>TxtLevel</TT></A>).</P>
! 6453: <P>
! 6454: To generate the translation of each section in a different file (see <A
! 6455: href="#changemainfile">rule <TT>ChangeMainFile</TT></A>), the name of these
! 6456: files might be defined by the following variable:</P>
! 6457: <PRE>
! 6458: VarOutpuFile : FileName Value(SectionNumber)
! 6459: Extension;
! 6460: </PRE>
! 6461: <P>
! 6462: If <TT>output.txt</TT>is the name of the <A name="varoutputfile">output
! 6463: file</A>specified when starting the translation program, translatedsections
! 6464: are written in files <TT>output1.txt</TT>, <TT>output2.txt</TT>,etc.</P>
! 6465: </BLOCKQUOTE>
! 6466: </DIV>
! 6467:
! 6468: <DIV class="subsection">
! 6469: <H3>Translating structure elements</H3>
! 6470:
! 6471: <P>
! 6472: The <TT>RULES</TT> keyword introduces the translation rules which will be
! 6473: applied to the various structured element types. Translation rules can be
! 6474: specified for each element type defined in the structure schema, including the
! 6475: base types defined implicitly, whose names are <TT>TEXT_UNIT</TT>,
! 6476: <TT>PICTURE_UNIT</TT>, <TT>SYMBOL_UNIT</TT>, <TT>GRAPHIC_UNIT</TT> and
! 6477: <TT>PAGE_UNIT</TT> in the English version of Thot or <TT>TEXTE</TT>,
! 6478: <TT>IMAGE</TT>, <TT>SYMBOLE</TT>, <TT>GRAPHIQUE</TT> and <TT>PAGE</TT> in the
! 6479: French version. But it is not necessary to specify rules for every defined
! 6480: type.</P>
! 6481: <P>
! 6482: If there are no translation rules for an element type, the elements that it
! 6483: contains (and which may have rules themselves) will still be translated, but
! 6484: the translator will produce nothing for the element itself. To make the
! 6485: translator completely ignore the content of an element the <A
! 6486: href="#remove"><TT>Remove</TT> rule</A> must be used.</P>
! 6487: <P>
! 6488: The translation rules for an element type defined in the structure schema are
! 6489: written using the name of the type followed by a colon and the list of
! 6490: applicable rules. When the element type is a <A href="#pairs">mark pair</A>,
! 6491: but only in this case, the type name must be preceded by the <TT>First</TT> or
! 6492: <TT>Second</TT> keyword. This keyword indicates whether the rules that follow
! 6493: apply to the first or second mark of the pair.</P>
! 6494: <P>
! 6495: The list of rules can take several forms. It may be a simple non-conditional
! 6496: rule. It can also be formed by a condition followed by one or more simple
! 6497: rules. Or it can be a block of rules beginning with the <TT>BEGIN</TT>
! 6498: keyword and ending with the <TT>END</TT> keyword and a semicolon. This block
! 6499: of rules can contain one or more simple rules and/or one or more conditions,
! 6500: each followed by one or more simple rules.</P>
! 6501: <PRE>
! 6502: ElemSeq = TransType < TransType > .
! 6503: TransType = [ FirstSec ] ElemID ':' RuleSeq .
! 6504: FirstSec = 'First' / 'Second' .
! 6505: RuleSeq = Rule / 'BEGIN' < Rule > 'END' ';' .
! 6506: Rule = SimpleRule / ConditionBlock .
! 6507: ConditionBlock = 'IF' ConditionSeq SimpleRuleSeq .
! 6508: SimpleRuleSeq = 'BEGIN' < SimpleRule > 'END' ';' /
! 6509: SimpleRule .
! 6510: </PRE>
! 6511: </DIV>
! 6512:
! 6513: <DIV class="subsection">
! 6514: <H3><A name="transcond">Conditional rules</A></H3>
! 6515:
! 6516: <P>
! 6517: In a translation schema, the translation rules are either associated with
! 6518: element types or with attribute values or with a specific presentation. They
! 6519: are applied by the translator each time an element of the corresponding type
! 6520: is encountered in the translated document or each time the attribute value is
! 6521: carried by an element or also, each time the specific translation is attached
! 6522: to an element. This systematic application of the rules can be relaxed: it is
! 6523: possible to add a condition to one or more rules, so that these rules are only
! 6524: applied when the condition is true.</P>
! 6525: <P>
! 6526: A condition begins with the keyword <TT>IF</TT>, followed by a sequence of
! 6527: elementary conditions. Elementary conditions are separated from each other by
! 6528: the <TT>AND</TT> keyword. If there is only one elementary condition, this
! 6529: keyword is absent. The rules are only applied if all the elementary
! 6530: conditions are true. The elementary condition can be negative; it is then
! 6531: preceded by the <TT>NOT</TT> keyword.</P>
! 6532: <P>
! 6533: When the translation rule(s) controlled by the condition apply to a reference
! 6534: element or a reference attribute, an elementary condition can also apply to
! 6535: element referred by this reference. The <TT>Target</TT> keyword is used for
! 6536: that purpose. It must appear before the keyword defining the condition
! 6537: type.</P>
! 6538: <P>
! 6539: Depending on their type, some conditions may apply either to the element with
! 6540: which they are associated, or to one of its ancestor. In the case od an
! 6541: ancestor, the key word <TT>Ancestor</TT> must be used, followed by</P>
! 6542: <UL>
! 6543: <LI>either an integer which represents the number of levels in thetree between
! 6544: the element and the ancestor of interest,
! 6545: <LI>or the type name of the ancestor of interest. If that type isdefined in a
! 6546: separate structure schema, the name of that schema mustfollow between
! 6547: parentheses.
! 6548: </UL>
! 6549: <P>
! 6550: There is a special case for the parent element, which can be simplywritten
! 6551: <TT>Parent</TT>instead of <TT>Ancestor 1</TT>.</P>
! 6552: <P>
! 6553: Only conditions <TT>First</TT>, <TT>Last</TT>, <TT>Referred</TT>,
! 6554: <TT>Within</TT>, <TT>Attributes</TT>, <TT>Presentation</TT>, <TT>Comment</TT>
! 6555: and those concerning an attribute or a specific presentation can apply to an
! 6556: ancestor. Conditions <TT>Defined</TT>, <TT>FirstRef</TT>, <TT>LastRef</TT>,
! 6557: <TT>ExternalRef</TT>, <TT>Alphabet</TT>, <TT>FirstAttr</TT>,
! 6558: <TT>LastAttr</TT>, <TT>ComputedPage</TT>, <TT>StartPage</TT>,
! 6559: <TT>UserPage</TT>, <TT>ReminderPage</TT>, <TT>Empty</TT> cannot be preceded by
! 6560: keywords <TT>Parent</TT> or <TT>Ancestor</TT>.</P>
! 6561: <P>
! 6562: In condition <TT>Referred</TT> and in the condition that applies to a named
! 6563: attribute, a symbol <TT>*</TT> can indicate that the condition is related only
! 6564: to the element itself. If this symbol is not present, not only the element is
! 6565: considered, but also its ancestor, at any level.</P>
! 6566: <P>
! 6567: The form of an elementary condition varies according to the type of
! 6568: condition.</P>
! 6569:
! 6570: <DIV class="subsubsection">
! 6571: <H4>Conditions based on the logical position of the element</H4>
! 6572:
! 6573: <P>
! 6574: The condition can be on the position of the element in the document's logical
! 6575: structure tree. It is possible to test whether the element is the first
! 6576: (<TT>First</TT>) or last (<TT>Last</TT>) among its siblings or if it is not
! 6577: the first (<TT>NOT First</TT>) or not the last (<TT>NOT Last</TT>).</P>
! 6578: <P>
! 6579: It is also possible to test if the element is contained in an element of a
! 6580: given type (<TT>Within</TT>) or if it is not (<TT>NOT Within</TT>). If that
! 6581: element type is defined in a structure schema which is not the one which
! 6582: corresponds to the translation schema, the type name of this element must be
! 6583: followed, between parentheses, by the name of the structure schema which
! 6584: defines it.</P>
! 6585: <P>
! 6586: If the keyword <TT>Within</TT> is preceded by <TT>Immediately</TT>, the
! 6587: condition is satisfied only if the <EM>parent</EM> element has the type
! 6588: indicated. If the word <TT>Immediately</TT> is missing, the condition is
! 6589: satisfied if any <EM>ancestor</EM> has the type indicated.</P>
! 6590: <P>
! 6591: An integer <I>n</I> can appear between the keyword <TT>Within</TT> and the
! 6592: type. It specifies the number of ancestors of the indicated type that must be
! 6593: present for the condition to be satisfied. If the keyword
! 6594: <TT>Immediately</TT> is also present, the <I>n</I> immediate ancestors of the
! 6595: element must have the indicated type. The integer <I>n</I> must be positive
! 6596: or zero. It can be preceded by <TT><</TT> or <TT>></TT> to indicate a
! 6597: maximum or minimum number of ancestors. If these symbols are missing, the
! 6598: condition is satisfied only if it exists exactly <I>n</I> ancestors. When
! 6599: this number is missing, it is equivalent to > 0.</P>
! 6600: </DIV>
! 6601:
! 6602: <DIV class="subsubsection">
! 6603: <H4>Conditions on references</H4>
! 6604:
! 6605: <P>
! 6606: References may be taken into account in conditions, which can be based on the
! 6607: fact that the element, or one of its ancestors (unless symbol <TT>*</TT> is
! 6608: present), is designated by a at least one reference (<TT>Referred</TT>) or by
! 6609: none (<TT>NOT Referred</TT>). If the element or attribute to which the
! 6610: condition is attached is a reference, the condition can be based on the fact
! 6611: that it acts as the first reference to the designated element
! 6612: (<TT>FirstRef</TT>), or as the last (<TT>LastRef</TT>), or as a reference to
! 6613: an element located in another document (<TT>ExternalRef</TT>). Like all
! 6614: conditions, conditions on references can be inverted by the <TT>NOT</TT>
! 6615: keyword.</P>
! 6616: </DIV>
! 6617:
! 6618: <DIV class="subsubsection">
! 6619: <H4>Conditions on the parameters</H4>
! 6620:
! 6621: <P>
! 6622: Elements which are <A href="#param">parameters</A> can be given a particular
! 6623: condition which is based on whether or not the parameter is given a value in
! 6624: the document (<TT>Defined</TT> or <TT>NOT Defined</TT>, respectively).</P>
! 6625: </DIV>
! 6626:
! 6627: <DIV class="subsubsection">
! 6628: <H4>Conditions on the alphabets</H4>
! 6629:
! 6630: <P>
! 6631: The character string base type (and only this type) can use the condition
! 6632: <TT>Alphabet = a</TT> which indicates that the translation rule(s) should only
! 6633: apply if the alphabet of the character string is the one whose name appears
! 6634: after the equals sign (or is not, if there is a preceding <TT>NOT</TT>
! 6635: keyword). This condition cannot be applied to translation rules of an
! 6636: attribute.</P>
! 6637: <P>
! 6638: In the current implementation of Thot, the available alphabets are the
! 6639: <TT>Latin</TT> alphabet and the <TT>Greek</TT> alphabet.</P>
! 6640: </DIV>
! 6641:
! 6642: <DIV class="subsubsection">
! 6643: <H4>Conditions on page breaks</H4>
! 6644:
! 6645: <P>
! 6646: The page break base type (and only this type) can use the following
! 6647: conditions: <TT>ComputedPage</TT>, <TT>StartPage</TT>, <TT>UserPage</TT>, and
! 6648: <TT>ReminderPage</TT>. The <TT>ComputedPage</TT> condition indicates that the
! 6649: translation rule(s) should apply if the page break was created automatically
! 6650: by Thot; the <TT>StartPage</TT> condition is true if the page break is
! 6651: generated before the element by the <TT>Page</TT> rule of the P language; the
! 6652: <TT>UserPage</TT> condition applies if the page break was inserted by the
! 6653: user; and the <TT>ReminderPage</TT> is applied if the page break is a reminder
! 6654: of page breaking.</P>
! 6655: </DIV>
! 6656:
! 6657: <DIV class="subsubsection">
! 6658: <H4>Conditions on the element's content</H4>
! 6659:
! 6660: <P>
! 6661: The condition can be based on whether or not the element is empty. An element
! 6662: which has no children or whose leaves are all empty is considered to be empty
! 6663: itself. This condition is expressed by the <TT>Empty</TT> keyword, optionally
! 6664: preceded by the <TT>NOT</TT> keyword.</P>
! 6665: </DIV>
! 6666:
! 6667: <DIV class="subsubsection">
! 6668: <H4>Conditions on the presence of comments</H4>
! 6669:
! 6670: <P>
! 6671: The condition can be based on the presence or absence of comments associated
! 6672: with the translated element. This condition is expressed by the keyword
! 6673: <TT>Comment</TT>, optionally preceded by the keyword <TT>NOT</TT>.</P>
! 6674: </DIV>
! 6675:
! 6676: <DIV class="subsubsection">
! 6677: <H4>Conditions on the presence of specific presentation rules</H4>
! 6678:
! 6679: <P>
! 6680: The condition can be based on the presence or absence of specific presentation
! 6681: rules associated with the translated element, whatever the rules, their value
! 6682: or their number. This condition is expressed by the keyword
! 6683: <TT>Presentation</TT>, optionally preceded by the <TT>NOT</TT> keyword.</P>
! 6684: </DIV>
! 6685:
! 6686: <DIV class="subsubsection">
! 6687: <H4>Conditions on the presence of logical attributes</H4>
! 6688:
! 6689: <P>
! 6690: In the same way, the condition can be based on the presence or absence of
! 6691: attributes associated with the translated elements, no matter what the
! 6692: attributes or their values. The <TT>Attributes</TT> keyword expresses this
! 6693: condition.</P>
! 6694: </DIV>
! 6695:
! 6696: <DIV class="subsubsection">
! 6697: <H4>Conditions on logical attributes</H4>
! 6698:
! 6699: <P>
! 6700: If the condition appears in the translation rules of an attribute, the
! 6701: <TT>FirstAttr</TT> and <TT>LastAttr</TT> keywords can be used to indicate that
! 6702: the rules must only be applied if this attribute is the first attribute for
! 6703: the translated element or if it is the last (respectively). These conditions
! 6704: can also be inverted by the <TT>NOT</TT> keyword.</P>
! 6705: <P>
! 6706: Another type of condition can only be applied to the translation rules when
! 6707: the element being processed (or one of its ancestors if symbol <TT>*</TT> is
! 6708: missing) has a certain attribute, perhaps with a certain value or, in
! 6709: contrast, when the element does not have this attribute with this value. The
! 6710: condition is specified by writing the name of the attribute after the keyword
! 6711: <TT>IF</TT> or <TT>AND</TT>. The <TT>NOT</TT> keyword can be used to invert
! 6712: the condition. If the translation rules must be applied to any element which
! 6713: has this attribute (or does not have it, if the condition is inverted) no
! 6714: matter what the attribute's value, the condition is complete. If, in
! 6715: contrast, the condition applies to one or more values of the attribute, these
! 6716: are indicated after the name of the attribute, except for reference attributes
! 6717: which do not have values.</P>
! 6718: <P>
! 6719: The representation of the values of an <A name="relattr">attribute</A> in a
! 6720: condition depends on the attribute's type. For attributes with enumerated or
! 6721: textual types, the value (a name or character string between apostrophes,
! 6722: respectively) is simply preceded by an equals sign. For numeric attributes,
! 6723: the condition can be based on a single value or on a range of values. In the
! 6724: case of a unique value, this value (an integer) is simply preceded by an
! 6725: equals sign. Conditions based on ranges of values have several forms:</P>
! 6726: <UL>
! 6727: <LI>all values less than a given value (the value is preceded by a``less
! 6728: than'' sign).
! 6729: <LI>all values greater than a given value (the value is preceded by a``greater
! 6730: than'' sign).
! 6731: <LI>all values falling in an interval, bounds included. The rangeof values is
! 6732: then specified <TT>IN [</TT>Minimum <TT>..</TT>Maximum<TT>]</TT>,where Minimum
! 6733: and Maximum are integers.
! 6734: </UL>
! 6735: <P>
! 6736: All numeric values may be negative. The integer is simply preceded bya minus
! 6737: sign.</P>
! 6738: <P>
! 6739: Both local and global attributes can be used in conditions.</P>
! 6740: </DIV>
! 6741:
! 6742: <DIV class="subsubsection">
! 6743: <H4>Conditions on specific presentation rules</H4>
! 6744:
! 6745: <P>
! 6746: It is possible to apply translation rules only when the element being
! 6747: processed has or does not have a specific presentation rule, possibly with a
! 6748: certain value. The condition is specified by writing the name of the
! 6749: presentation rule after the keyword <TT>IF</TT> or <TT>AND</TT>. The
! 6750: <TT>NOT</TT> keyword can be used to invert the condition. If the translation
! 6751: rules must be applied to any element which has this presentation rule (or does
! 6752: not have it, if the condition is inverted) no matter what the rule's value,
! 6753: the condition is complete. If, in contrast, the condition applies to one or
! 6754: more values of the rule, these are indicated after the name of the
! 6755: attribute.</P>
! 6756: <P>
! 6757: The representation of presentation rule values in a condition is similar to
! 6758: that for attribute values. The representation of these values depend on the
! 6759: type of the presentation rule. There are three categories of presentation
! 6760: rules:</P>
! 6761: <UL>
! 6762: <LI>those taking numeric values (<TT>Size, Indent, LineSpacing,
! 6763: LineWeight</TT>),
! 6764: <LI>those with values taken from a predefined list (<TT>Adjust, Justify,
! 6765: Hyphenate, Style, Font, UnderLine, Thickness, LineStyle</TT>),
! 6766: <LI>those whose value is a name (<TT>FillPattern, Background,
! 6767: Foreground</TT>).
! 6768: </UL>
! 6769: <P>
! 6770: For presentation rules which take numeric values, the condition can take a
! 6771: unique value or a range of values. In the case of a unique value, this value
! 6772: (an integer) is simply preceded by an equals sign. Conditions based on ranges
! 6773: of values have several forms:</P>
! 6774: <UL>
! 6775: <LI>all values less than a given value (the value is preceded by a``less
! 6776: than'' sign).
! 6777: <LI>all values greater than a given value (the value is preceded by a``greater
! 6778: than'' sign).
! 6779: <LI>all values falling in an interval, bounds included. The rangeof values is
! 6780: then specified <TT>IN [</TT>Minimum <TT>..</TT>Maximum<TT>]</TT>,where Minimum
! 6781: and Maximum are integers.
! 6782: </UL>
! 6783: <P>
! 6784: Values for the <TT>Indent</TT>rule may be negative. The integer is thensimply
! 6785: preceded by a minus sign and represents how far the first linestarts to the
! 6786: left of the other lines.</P>
! 6787: <P>
! 6788: For presentation rules whose values are taken from predefined lists, the value
! 6789: which satisfies the condition is indicated by an equals sign followed by the
! 6790: name of the value.</P>
! 6791: <P>
! 6792: For presentation rule whose values are names, the value which satisfies the
! 6793: condition is indicated by the equals sign followed by the value's name. The
! 6794: names of fill patterns (the <TT>FillPattern</TT> rule) and of colors (the
! 6795: <TT>Foreground</TT> and <TT>Background</TT> rules) known to Thot are the same
! 6796: as in the P language.</P>
! 6797: <P>
! 6798: The syntax of conditions based on the specific presentation is the same as the
! 6799: syntax used to express the <A href="#prestrans">translation of specific
! 6800: presentation rules</A>.</P>
! 6801: <P>
! 6802: When a condition has only one rule, the condition is simply followed by that
! 6803: rule. If it has several rules, they are placed after the condition between
! 6804: the keywords <TT>BEGIN</TT> and <TT>END</TT>.</P>
! 6805: <PRE>
! 6806: ConditionSeq = Condition [ 'AND' Condition ] .
! 6807: Condition = [ 'NOT' ] [ 'Target' ] Cond .
! 6808: Cond = CondElem / CondAscend .
! 6809: CondElem ='FirstRef' / 'LastRef' /
! 6810: 'ExternalRef' /
! 6811: 'Defined' /
! 6812: 'Alphabet' '=' Alphabet /
! 6813: 'ComputedPage' / 'StartPage' /
! 6814: 'UserPage' / 'ReminderPage' /
! 6815: 'Empty' /
! 6816: 'FirstAttr' / 'LastAttr' .
! 6817: CondAscend = [ Ascend ] CondOnAscend .
! 6818: Ascend = '*' / 'Parent' / 'Ancestor' LevelOrType .
! 6819: LevelOrType = CondRelLevel / ElemID [ ExtStruct ] .
! 6820: CondRelLevel = NUMBER .
! 6821: CondOnAscend ='First' / 'Last' /
! 6822: 'Referred' /
! 6823: [ 'Immediately' ] 'Within' [ NumParent ]
! 6824: ElemID [ ExtStruct ] /
! 6825: 'Attributes' /
! 6826: AttrID [ RelatAttr ] /
! 6827: 'Presentation' /
! 6828: PresRule /
! 6829: 'Comment' .
! 6830: NumParent = [ GreaterLess ] NParent .
! 6831: GreaterLess = '>' / '<' .
! 6832: NParent = NUMBER.
! 6833: ExtStruct = '(' ElemID ')' .
! 6834: Alphabet = NAME .
! 6835: RelatAttr ='=' Value /
! 6836: '>' [ '-' ] Minimum /
! 6837: '<' [ '-' ] Maximum /
! 6838: 'IN' '[' [ '-' ] MinInterval '..'
! 6839: [ '-' ] MaxInterval ']' .
! 6840: Value = [ '-' ] IntegerVal / TextVal / AttrValue .
! 6841: Minimum = NUMBER .
! 6842: Maximum = NUMBER .
! 6843: MinInterval = NUMBER .
! 6844: MaxInterval = NUMBER .
! 6845: IntegerVal = NUMBER .
! 6846: TextVal = STRING .
! 6847: AttrValue = NAME .
! 6848: </PRE>
! 6849: <BLOCKQUOTE class="example">
! 6850: <P>
! 6851: <STRONG>Example:</STRONG></P>
! 6852: <P>
! 6853: Suppose that after each element of type Section_Title it is useful toproduce
! 6854: the text <TT>\label{SectX}</TT>where <TT>X</TT>represents thesection number,
! 6855: but only if the section is designated by one or morereferences in the
! 6856: document. The following conditional rule producesthis effect:</P>
! 6857: <PRE>
! 6858: RULES
! 6859: Section_Title :
! 6860: IF Referred
! 6861: Create ('\label{Sect' Value(UniqueSectNum)
! 6862: '}\12') After;
! 6863: </PRE>
! 6864: <P>
! 6865: (the declaration of the <A href="#prestrans"><TT>UniqueSectNum</TT>
! 6866: counter</A>is given above). The string <TT>\12</TT>represents aline
! 6867: break.</P>
! 6868: </BLOCKQUOTE>
! 6869: <BLOCKQUOTE class="example">
! 6870: <P>
! 6871: <STRONG>Example:</STRONG></P>
! 6872: <P>
! 6873: Suppose that for elements of the Elmnt type it would be useful toproduce a
! 6874: character indicating the value of the numeric attributeLevel associated with
! 6875: the element: an ``A'' for all values of Levelless than 3, a ``B'' for values
! 6876: between 3 and 10 and a ``C'' forvalues greater than 10. This can be achieved
! 6877: by writing the followingrules for the Elmnt type:</P>
! 6878: <PRE>
! 6879: RULES
! 6880: Elmnt :
! 6881: BEGIN
! 6882: IF Level < 3
! 6883: Create 'A';
! 6884: IF Level IN [3..10]
! 6885: Create 'B';
! 6886: IF Level > 10
! 6887: Create 'C';
! 6888: END;
! 6889: </PRE>
! 6890: </BLOCKQUOTE>
! 6891: </DIV>
! 6892: </DIV>
! 6893:
! 6894: <DIV class="subsection">
! 6895: <H3>Translation rules</H3>
! 6896:
! 6897: <P>
! 6898: Thirteen types of translation rules can be associated with element types and
! 6899: attribute values. They are the <TT>Create</TT>, <TT>Write</TT>,
! 6900: <TT>Read</TT>, <TT>Include</TT>, <TT>Get</TT>, <TT>Copy</TT>, <TT>Use</TT>,
! 6901: <TT>Remove</TT>, <TT>NoTranslation</TT>, <TT>NoLineBreak</TT>,
! 6902: <TT>ChangeMainFile</TT>, <TT>Set</TT>, <TT>Add</TT> rules. Each rule has its
! 6903: own syntax, although they are all based on very similar models.</P>
! 6904: <PRE>
! 6905: SimpleRule = 'Create' [ 'IN' VarID ] Object
! 6906: [ Position ] ';' /
! 6907: 'Write' Object [ Position ] ';' /
! 6908: 'Read' BufferID [ Position ] ';' /
! 6909: 'Include' File [ Position ] ';' /
! 6910: 'Get' [ RelPosition ] ElemID
! 6911: [ ExtStruct ]
! 6912: [ Position ] ';' /
! 6913: 'Copy' [ RelPosition ] ElemID
! 6914: [ ExtStruct ]
! 6915: [ Position ] ';' /
! 6916: 'Use' TrSchema [ 'For' ElemID ] ';' /
! 6917: 'Remove' ';' /
! 6918: 'NoTranslation' ';' /
! 6919: 'NoLineBreak' ';' /
! 6920: 'ChangeMainFile' VarID [ Position ] ';' /
! 6921: 'Set' CounterID InitValue
! 6922: [ Position ] ';' /
! 6923: 'Add' CounterID Increment
! 6924: [ Position ] ';' .
! 6925: </PRE>
! 6926: </DIV>
! 6927:
! 6928: <DIV class="subsection">
! 6929: <H3><A name="create">The <TT>Create</TT> rule</A></H3>
! 6930:
! 6931: <P>
! 6932: The most frequently used rule is undoubtedly the <TT>Create</TT> rule, which
! 6933: generates fixed or variable text (called an <EM>object</EM>) in the output
! 6934: file. The generated text can be made to appear either before or after the
! 6935: content of the element to which the rule applies. The rule begins with the
! 6936: <TT>Create</TT> keyword, followed by a specifier for the object and a keyword
! 6937: (<TT>Before</TT> or <TT>After</TT>) indicating the position of the generated
! 6938: text (<A href="#order">before or after</A> the element's content). If the
! 6939: position is not indicated, the object will be generated before the element's
! 6940: content. This rule, like all translation rules, is terminated by a
! 6941: semicolon.</P>
! 6942: <P>
! 6943: The <TT>Create</TT> keyword can be followed by the <TT>IN</TT> keyword and by
! 6944: the name of a variable. This means that the text generated by the rule must
! 6945: not be written in the main output file, but in the file whose name is
! 6946: specified by the variable.</P>
! 6947: <P>
! 6948: This allows the translation program to generate text in different files during
! 6949: the same run. These files do not need to be explicetely declared or opened.
! 6950: They do not need to be closed either. As soon as the translation program
! 6951: executes a <TT>Create</TT> rule for a file that is not yet open, it opens the
! 6952: file. These files are closed when the translation is finished.</P>
! 6953: <PRE>
! 6954: 'Create' [ 'IN' VarID ] Object
! 6955: [ Position ] ';'
! 6956: Object = ConstID / CharString /
! 6957: BufferID /
! 6958: VarID /
! 6959: '(' Function < Function > ')' /
! 6960: AttrID /
! 6961: 'Value' /
! 6962: 'Content' /
! 6963: 'Comment' /
! 6964: 'Attributes' /
! 6965: 'Presentation' /
! 6966: 'RefId' /
! 6967: 'PairId' /
! 6968: 'FileDir' /
! 6969: 'FileName' /
! 6970: 'Extension' /
! 6971: 'DocumentName' /
! 6972: 'DocumentDir' /
! 6973: [ 'Referred' ] ReferredObject .
! 6974: Position ='After' / 'Before' .
! 6975:
! 6976: ReferredObject = VarID /
! 6977: ElemID [ ExtStruct ] /
! 6978: 'RefId' /
! 6979: 'DocumentName' /
! 6980: 'DocumentDir' .
! 6981: </PRE>
! 6982: <P>
! 6983: The object to be generated can be:</P>
! 6984: <UL>
! 6985: <LI>a constant string, specified by its name if it is declared inthe schema's
! 6986: <TT>CONST</TT>section, or given directly as a value betweenapostrophes;
! 6987: <LI>the contents of a buffer, designated by the name of the buffer;
! 6988: <LI>a variable, designated by its name if it is declared in thetranslation
! 6989: schema's <TT>VAR</TT>section, or given directly betweenparentheses. The text
! 6990: generated is the value of that variableevaluated for the element to which the
! 6991: rule applies.
! 6992: <LI>the value of an attribute, if the element being translated has
! 6993: thisattribute. The attribute is specified by its name;
! 6994: <LI>the value of a specific presentation rule. This object can onlybe
! 6995: generated if the translation rule is for a <A href="#prestransl">specific
! 6996: presentation rule</A>. It is specified by the <TT>Value</TT>keyword;
! 6997: <LI>the element's content. That is, the content of the leaves ofthe subtree
! 6998: of the translated element. This is specified by the<TT>Content</TT>keyword;
! 6999: <LI>the comment attached to the element. When the element doesn'thave a
! 7000: comment, nothing is generated. This is indicated by
! 7001: the<TT>Comment</TT>keyword;
! 7002: <LI>the translation of all attributes of the element (which isprimarily used
! 7003: to apply the attribute translation rules<A href="#order">before</A>those of
! 7004: the element type). This isspecified by the <TT>Attributes</TT>keyword.
! 7005: <LI>the translation of all of the element's specific presentationrules (which
! 7006: is primarily used to apply the translation rules for thespecific presentation
! 7007: rules <A href="#order">before</A>those of theelement or its attributes). This
! 7008: option is specifiedby the <TT>Presentation</TT>keyword;
! 7009: <LI>The value of the reference's identifier.<BR>Thot associates a
! 7010: uniqueidentifier with eachelement in a document. Thisidentifier (called
! 7011: <EM>reference's identifier</EM>or <EM>label</EM>) is acharacter string
! 7012: containing the letter `L' followed by digits. Thot uses itin references for
! 7013: identifying the referred element.<BR>The <TT>RefId</TT>keyword produces the
! 7014: reference's identifierof the element to which the translation rule is applied,
! 7015: or the reference'sidentifier of its first ancestor that is referred by a
! 7016: referenceor that can be referred by a reference.
! 7017: <LI>the value of a mark pair's unique identifier. This may only be usedfor <A
! 7018: href="#pairs">mark pairs</A>and is indicated by the<TT>PairId</TT>keyword.
! 7019: <LI>the directory containing the file being generated (this stringincludes an
! 7020: ending '/', if it is not empty). This is indicated by
! 7021: the<TT>FileDir</TT>keyword.
! 7022: <LI>the name of the file being generated (only the name, without thedirectory
! 7023: and without the extension). This is indicated by the <TT>FileName</TT>keyword.
! 7024: <LI>the extension of the file being generated (this string starts with adot,
! 7025: if it is not empty). This is indicated by the <TT>Extension</TT>keyword.
! 7026: <LI>the name of the document being translated. This is indicated bythe
! 7027: <TT>DocumentName</TT>keyword.
! 7028: <LI>the directory containing the document being translated. This isindicated
! 7029: by the <TT>DocumentDir</TT>keyword.
! 7030: </UL>
! 7031: <P>
! 7032: When the rule applies to a reference (an element or an attribute defined as a
! 7033: reference in the structure schema), it can generate a text related to the
! 7034: element referred by that reference. The rule name is then followed the
! 7035: <TT>Referred</TT> keyword and a specification of the object to be generated
! 7036: for the referred element. This specification can be:</P>
! 7037: <UL>
! 7038: <LI>the name of a variable. The rule generates the value of thatvariable,
! 7039: computed for the referred element.
! 7040: <LI>an element type. The rule generates the translation of the elementof that
! 7041: type, which is in the subtree of the referred element. If thiselement is not
! 7042: defined in the structure schema which corresponds to thetranslation schema
! 7043: (that is, an object defined in another schema), theelement's type name must be
! 7044: followed by the name of its structureschema between parentheses.
! 7045: <LI>the <TT>RefId</TT>keyword. The rule generates the reference'sidentifier
! 7046: of the referred element.
! 7047: <LI>the <TT>DocumentName</TT>keyword. The rule generates the name ofthe
! 7048: document to which the referred element belongs.
! 7049: <LI>the <TT>DocumentDir</TT>keyword. The rule generates the name ofthe
! 7050: directory that contains the document of the referred element.
! 7051: </UL>
! 7052: </DIV>
! 7053:
! 7054: <DIV class="subsection">
! 7055: <H3><A name="writerule">The <TT>Write</TT> rule</A></H3>
! 7056:
! 7057: <P>
! 7058: The <TT>Write</TT> has the same syntax as the <TT>Create</TT> rule. It also
! 7059: produces the same effect, but the generated text is displayed on the user's
! 7060: terminal during the translation of the document, instead of being produced in
! 7061: the translated document. This is useful for helping the user keep track of
! 7062: the progress of the translation and for prompting the user on the terminal for
! 7063: input required by the <TT>Read</TT> rule.</P>
! 7064: <PRE>
! 7065: 'Write' Object [ Position ] ';'
! 7066: </PRE>
! 7067: <P>
! 7068: Notice: if the translator is launched by the editor (by the ``Save as''
! 7069: command), messages produced by the <TT>Write</TT> rule are not displayed.</P>
! 7070: <BLOCKQUOTE class="example">
! 7071: <P>
! 7072: <STRONG>Example:</STRONG></P>
! 7073: <P>
! 7074: To make the translator display the number of each section beingtranslated on
! 7075: the user's terminal, the following rule is specified forthe
! 7076: <TT>Section</TT>element type:</P>
! 7077: <PRE>
! 7078: Section : BEGIN
! 7079: Write VarSection;
! 7080: ...
! 7081: END;
! 7082: </PRE>
! 7083: <P>
! 7084: (see <A href="#varsectexample">above</A>for the definition of
! 7085: the<TT>VarSection</TT>variable).</P>
! 7086: <P>
! 7087: To display text on the terminal before issuing a read operation with the
! 7088: <TT>Read</TT> rule, the following rule is used:</P>
! 7089: <PRE>
! 7090: BEGIN
! 7091: Write 'Enter the name of the destination: ';
! 7092: ...
! 7093: END;
! 7094: </PRE>
! 7095: </BLOCKQUOTE>
! 7096: </DIV>
! 7097:
! 7098: <DIV class="subsection">
! 7099: <H3><A name="readrule">The <TT>Read</TT> rule</A></H3>
! 7100:
! 7101: <P>
! 7102: The <TT>Read</TT> rule reads text from the terminal during the translation of
! 7103: the document and saves the text read in one of the buffers declared in the
! 7104: <TT>BUFFERS</TT> section of the schema. The buffer to be used is indicated by
! 7105: its name, after the <TT>READ</TT> keyword. This name can be followed, as in
! 7106: the <TT>Create</TT> and <TT>Write</TT> rules, by a keyword indicating if the
! 7107: read operation must be performed <TT>Before</TT> or <TT>After</TT> the
! 7108: translation of the element's content. If this keyword is absent, the read
! 7109: operation is done beforehand. The text is read into the buffer and remains
! 7110: there until a rule using the same buffer --- possibly the same rule --- is
! 7111: applied.</P>
! 7112: <PRE>
! 7113: 'Read' BufferID [ Position ] ';'
! 7114: </PRE>
! 7115: <BLOCKQUOTE class="example">
! 7116: <P>
! 7117: <STRONG>Example:</STRONG></P>
! 7118: <P>
! 7119: The following set of rules tells the user that the translator iswaiting for
! 7120: the entry of some text, reads this text into a buffer andcopies the text into
! 7121: the translated document.</P>
! 7122: <PRE>
! 7123: BEGIN
! 7124: Write 'Enter the name of the destination: ';
! 7125: Read DestName;
! 7126: Create DestName;
! 7127: ...
! 7128: END;
! 7129: </PRE>
! 7130: <P>
! 7131: (see <A href="#destname">above</A>the definition of <TT>DestName</TT>).</P>
! 7132: </BLOCKQUOTE>
! 7133: </DIV>
! 7134:
! 7135: <DIV class="subsection">
! 7136: <H3>The <TT>Include</TT> rule</H3>
! 7137:
! 7138: <P>
! 7139: The <TT>Include</TT> rule, like the <TT>Create</TT> rule, is used to produce
! 7140: text in the translated document. It inserts constant text which is not
! 7141: defined in the translation schema, but is instead taken from a file. The
! 7142: file's name is specified after the <TT>Include</TT> keyword, either directly
! 7143: as a character string between apostrophes or as the name of one of the buffers
! 7144: declared in the <TT>BUFFERS</TT> section of the schema. In the latter case,
! 7145: the buffer is assumed to contain the file's name. This can be used when the
! 7146: included file's name is known only at the moment of translation. This only
! 7147: requires that the <TT>Include</TT> rule is preceded by a <TT>Read</TT> rule
! 7148: which puts the name of the file desired by the user into the buffer.</P>
! 7149: <P>
! 7150: Like the other rules, it is possible to specify whether the inclusion will
! 7151: occur before or after the element's content, with the default being before.
! 7152: The file inclusion is only done at the moment of translation, not during the
! 7153: compilation of the translation schema. Thus, the file to be included need not
! 7154: exist during the compilation, but it must be accessible at the time of
! 7155: translation. Its contents can also be modified between two translations, thus
! 7156: producing different results, even if neither the document or the translation
! 7157: schema are modified.</P>
! 7158: <P>
! 7159: During translation, the file to be included is searched for along the schema
! 7160: directory path (indicated by the environment variable <TT>THOTSCH</TT>). The
! 7161: file name is normally only composed of a simple name, without specification of
! 7162: a complete file path.</P>
! 7163: <PRE>
! 7164: 'Include' File [ Position ] ';'
! 7165: File = FileName / BufferID .
! 7166: FileName = STRING .
! 7167: </PRE>
! 7168: <BLOCKQUOTE class="example">
! 7169: <P>
! 7170: <STRONG>Example:</STRONG></P>
! 7171: <P>
! 7172: Suppose that it is desirable to print documents of the Article classwith a
! 7173: formatter which requires a number of declarations anddefinitions at the
! 7174: beginning of the file. The <TT>Include</TT>rule canbe used to achieve this.
! 7175: All the declarations and definitions areplaced in a file called
! 7176: <TT>DeclarArt</TT>and then the <TT>Article</TT>element type is given the
! 7177: following rule:</P>
! 7178: <PRE>
! 7179: Article : BEGIN
! 7180: Include 'DeclarArt' Before;
! 7181: ...
! 7182: END;
! 7183: </PRE>
! 7184: </BLOCKQUOTE>
! 7185: </DIV>
! 7186:
! 7187: <DIV class="subsection">
! 7188: <H3>The <TT>Get</TT> rule</H3>
! 7189:
! 7190: <P>
! 7191: The <TT>Get</TT> rule is used to change the order in which the elements appear
! 7192: in the translated document. More precisely, it produces the translation of a
! 7193: specified element before or after the translation of the content of the
! 7194: element to which the rule applies. The <TT>Before</TT> and <TT>After</TT>
! 7195: keywords are placed at the end of the rule to specify whether the operation
! 7196: should be performed before or after translation of the rule's element (the
! 7197: default is before). The type of the element to be moved must be specified
! 7198: after the <TT>Get</TT> keyword, optionally preceded by a keyword indicating
! 7199: where the element will be found in the logical structure of the document:</P>
! 7200: <DL>
! 7201: <DT><TT>Included</TT></DT>
! 7202: <DD>The element to be moved is the first element of the indicated typewhich is
! 7203: found inside the element to which the rule applies.
! 7204: </DD>
! 7205: <DT><TT>Referred</TT></DT>
! 7206: <DD>This keyword can only be used if the rule applies to a referenceelement.
! 7207: The element to be moved is either the element designated bythe reference (if
! 7208: that element is of the specified type), or the firstelement of the desired
! 7209: type contained within the element designated bythe reference.
! 7210: </DD>
! 7211: <DT>no keyword</DT>
! 7212: <DD>If the element to be moved is an associated element, defined in the<A
! 7213: href="#assocelem"><TT>ASSOC</TT> section</A>of the structure schema,all
! 7214: associated elements of this type whichhave not been translated yet are then
! 7215: translated. Certain elementsmay in fact have already been translated by a
! 7216: <TT>Get Referred</TT>rule.
! 7217: <P>
! 7218: If the element to be moved is not an associated element, the translator takes
! 7219: the first element of the indicated type from among the siblings of the rule's
! 7220: element. This is primarily used to change the order of the components of an
! 7221: aggregate.</P>
! 7222: </DD>
! 7223: </DL>
! 7224: <P>
! 7225: If the element to be moved is defined in a structure schema which is not the
! 7226: one which corresponds to the translation schema (in the case of an included
! 7227: object with a different schema), the type name of this element must be
! 7228: followed, between parentheses, by the name of the structure schema which
! 7229: defines it.</P>
! 7230: <PRE>
! 7231: 'Get' [ RelPosition ] ElemID
! 7232: [ ExtStruct ]
! 7233: [ Position ] ';' /
! 7234: RelPosition ='Included' / 'Referred' .
! 7235: ExtStruct = '(' ElemID ')' .
! 7236: </PRE>
! 7237: <P>
! 7238: The <TT>Get</TT> rule has no effect if the element which it is supposed to
! 7239: move has already been translated. Thus, the element will not be duplicated.
! 7240: It is generally best to associate the rule with the first element which will
! 7241: be encountered by the translator in its traversal of the document. Suppose an
! 7242: aggregate has two elements <TT>A</TT> and <TT>B</TT>, with <TT>A</TT>
! 7243: appearing first in the logical structure. To permute these two elements, a
! 7244: <TT>Get B before</TT> rule should be associated with the <TT>A</TT> element
! 7245: type, not the inverse. Similarly, a rule of the form <TT>Get Included X
! 7246: After</TT>, even though syntactically correct, makes no sense since, by the
! 7247: time it will be applied, after the translation of the contents of the element
! 7248: to which it is attached, the <TT>X</TT> element will already have been
! 7249: translated.</P>
! 7250: <P>
! 7251: The <TT>Get</TT> rule is the only way to obtain the translation of the
! 7252: associated elements. In fact, the translator only traverses the primary tree
! 7253: of the document and thus does not translate the associated elements, except
! 7254: when the translation is explicitly required by a <TT>Get Referred Type</TT> or
! 7255: <TT>Get Type</TT> rule where <TT>Type</TT> is an associated element type.</P>
! 7256: <BLOCKQUOTE class="example">
! 7257: <P>
! 7258: <STRONG>Example:</STRONG></P>
! 7259: <P>
! 7260: The structure schema defined figures as associated element which arecomposed
! 7261: of some content and a caption. Moreover, it is possible to makereferences to
! 7262: figures, using elements of the <TT>RefFigure</TT>type:</P>
! 7263: <PRE>
! 7264: ...
! 7265: RefFigure = REFERENCE(Figure);
! 7266: ASSOC
! 7267: Figure = BEGIN
! 7268: Content = NATURE;
! 7269: Caption = Text;
! 7270: END;
! 7271: ...
! 7272: </PRE>
! 7273: <P>
! 7274: Suppose it would be useful to make a figure appear in the translateddocument
! 7275: at the place in the text where the first reference to thefigure is made. If
! 7276: some figures are not referenced, then they wouldappear at the end of the
! 7277: document. Also, each figure's caption shouldappear before the content. The
! 7278: following rules in the translationschema will produce this result:</P>
! 7279: <PRE>
! 7280: Article : BEGIN
! 7281: ...
! 7282: Get Figures After;
! 7283: END;
! 7284: RefFigure : BEGIN
! 7285: If FirstRef Get Referred Figure;
! 7286: ...
! 7287: END;
! 7288: Content : BEGIN
! 7289: Get Caption Before;
! 7290: ...
! 7291: END;
! 7292: </PRE>
! 7293: </BLOCKQUOTE>
! 7294: </DIV>
! 7295:
! 7296: <DIV class="subsection">
! 7297: <H3>The <TT>Copy</TT> rule</H3>
! 7298:
! 7299: <P>
! 7300: Like the <TT>Get</TT> rule, the <TT>Copy</TT> rule generates the translation
! 7301: of a specified element, but it acts even if the element has already been
! 7302: translated and it allows to copy it or to translate it later. Both rules have
! 7303: the same syntax.</P>
! 7304: <PRE>
! 7305: 'Copy' [ RelPosition ] ElemID
! 7306: [ ExtStruct ] [ Position ] ';'
! 7307: </PRE>
! 7308: </DIV>
! 7309:
! 7310: <DIV class="subsection">
! 7311: <H3>The <TT>Use</TT> rule</H3>
! 7312:
! 7313: <P>
! 7314: The <TT>Use</TT> rule specifies the translation schema to be applied to
! 7315: objects of a certain class that are part of the document. This rule only
! 7316: appears in the rules for the root element of the document (the first type
! 7317: defined after the <TT>STRUCT</TT> keyword in the structure schema) or the
! 7318: rules of an element defined by an external structure (by another structure
! 7319: schema). Also, the <TT>Use</TT> rule cannot be conditional.</P>
! 7320: <P>
! 7321: If the rule is applied to an element defined by an external structure, the
! 7322: <TT>Use</TT> keyword is simply followed by the name of the translation schema
! 7323: to be used for element constructed according to that external structure. If
! 7324: the rule is applied to the document's root element, it is formed by the
! 7325: <TT>Use</TT> keyword followed by the translation schema's name, the
! 7326: <TT>For</TT> keyword and the name of the external structure to which the
! 7327: indicated translation schema should be applied.</P>
! 7328: <PRE>
! 7329: 'Use' TrSchema [ 'For' ElemID ] ';'
! 7330: TrSchema = NAME .
! 7331: </PRE>
! 7332: <P>
! 7333: If no <TT>Use</TT> rule defines the translation schema to be used for an
! 7334: external structure which appears in a document, the translator asks the user,
! 7335: during the translation process, which schema should be used. Thus, it is not
! 7336: necessary to give the translation schema a <TT>Use</TT> rule for every
! 7337: external structure used, especially when the choice of translation schemas is
! 7338: to be left to the user.</P>
! 7339: <P>
! 7340: Notice: if the translator is launched by the editor (by the ``Save as''
! 7341: command), prompts are not displayed.</P>
! 7342: <BLOCKQUOTE class="example">
! 7343: <P>
! 7344: <STRONG>Example:</STRONG></P>
! 7345: <P>
! 7346: The <TT>Article</TT>structure schema uses the
! 7347: <TT>Formula</TT>externalstructure, defined by another structure schema, for
! 7348: mathematical formulas:</P>
! 7349: <PRE>
! 7350: STRUCTURE Article;
! 7351: ...
! 7352: STRUCT
! 7353: Article = ...
! 7354: ...
! 7355: Formula_in_text = Formula;
! 7356: Isolated_formula = Formula;
! 7357: ...
! 7358: END
! 7359: </PRE>
! 7360: <P>
! 7361: Suppose that it would be useful to use the <TT>FormulaT</TT>translationschema
! 7362: for the formulas of an article. This can be expressed in twodifferent ways in
! 7363: the <TT>Article</TT>class translation schema, usingthe rules:</P>
! 7364: <PRE>
! 7365: RULES
! 7366: Article :
! 7367: Use FormulaT for Formula;
! 7368: </PRE>
! 7369: <P>
! 7370: or:</P>
! 7371: <PRE>
! 7372: RULES
! 7373: ...
! 7374: Formula :
! 7375: Use FormulaT;
! 7376: </PRE>
! 7377: </BLOCKQUOTE>
! 7378: </DIV>
! 7379:
! 7380: <DIV class="subsection">
! 7381: <H3><A name="remove">The <TT>Remove</TT> rule</A></H3>
! 7382:
! 7383: <P>
! 7384: The <TT>Remove</TT> rule indicates that nothing should be generated, in the
! 7385: translated document, for the content of the element to which the rule applies.
! 7386: The content of that element is simply ignored by the translator. This does
! 7387: not prevent the generation of text for the element itself, using the
! 7388: <TT>Create</TT> or <TT>Include</TT> rules, for example.</P>
! 7389: <P>
! 7390: The <TT>Remove</TT> rule is simply written with the <TT>Remove</TT> keyword.
! 7391: It is terminated, like all rules, by a semicolon.</P>
! 7392: <PRE>
! 7393: 'Remove' ';'
! 7394: </PRE>
! 7395: </DIV>
! 7396:
! 7397: <DIV class="subsection">
! 7398: <H3><A name="notrans">The <TT>NoTranslation</TT> rule</A></H3>
! 7399:
! 7400: <P>
! 7401: The <TT>NoTranslation</TT> rule indicates to the translator that it must not
! 7402: translate the content of the leaves of the element to which it applies. In
! 7403: contrast to the <TT>Remove</TT> rule, it does not suppress the content of the
! 7404: element, but it inhibits the translation of character strings, symbols, and
! 7405: graphical elements contained in the element. These are retrieved so that
! 7406: after the translation of the document, the rules of the <A
! 7407: href="#texttrans"><TT>TEXTTRANSLATE</TT>, <TT>SYMBTRANSLATE</TT> and
! 7408: <TT>GRAPHTRANSLATE</TT> sections</A> will not be applied to them.</P>
! 7409: <P>
! 7410: The <TT>NoTranslation</TT> rule is written with the <TT>NoTranslation</TT>
! 7411: keyword followed by a semicolon.</P>
! 7412: <PRE>
! 7413: 'NoTranslation' ';'
! 7414: </PRE>
! 7415: </DIV>
! 7416:
! 7417: <DIV class="subsection">
! 7418: <H3><A name="nolinebreak">The <TT>NoLineBreak</TT> rule</A></H3>
! 7419:
! 7420: <P>
! 7421: The <TT>NoLineBreak</TT> rule indicates to the translator that it must not
! 7422: generate additional line breaks in the output produced for the element to
! 7423: which it applies. This is as if it was an <A href="#linelength">instruction
! 7424: <TT>LINELENGTH 0;</TT></A> at the beginning of the translation schema, but
! 7425: only for the current element.</P>
! 7426: <P>
! 7427: The <TT>NoLineBreak</TT> rule is written with the <TT>NoLineBreak</TT> keyword
! 7428: followed by a semicolon.</P>
! 7429: <PRE>
! 7430: 'NoLineBreak' ';'
! 7431: </PRE>
! 7432: </DIV>
! 7433:
! 7434: <DIV class="subsection">
! 7435: <H3><A name="changemainfile">The <TT>ChangeMainFile</TT> rule</A></H3>
! 7436:
! 7437: <P>
! 7438: When the translation program starts, it opens a main output file, whose name
! 7439: is given as a parameter of the program. All <A href="#create"><TT>Create</TT>
! 7440: rules</A> without explicit indication of the output file write sequentially in
! 7441: this file. When a <TT>ChangeMainFile</TT> rule is executed, the main output
! 7442: file is closed and it is replaced by a new one, whose name is specified in the
! 7443: <TT>ChangeMainFile</TT> rule. The <TT>Create</TT> rules without indication of
! 7444: the output file that are then executed write in this new file. Several
! 7445: <TT>ChangeMainFile</TT> rules can be executed during the same translation, for
! 7446: dividing the main output into several files.</P>
! 7447: <P>
! 7448: This rule is written with the <TT>ChangeMainFile</TT> keyword followed by the
! 7449: name of a variable that specify the name of the new main file. The keyword
! 7450: <TT>Before</TT> or <TT>After</TT> can be placed at the end of the rule to
! 7451: specify whether the operation should be performed before or after translation
! 7452: of the rule's element (the default is before). This rule, like all translation
! 7453: rules, is terminated by a semicolon.</P>
! 7454: <PRE>
! 7455: 'ChangeMainFile' VarID [ Position ] ';'
! 7456: </PRE>
! 7457: <BLOCKQUOTE class="example">
! 7458: <P>
! 7459: <STRONG>Example:</STRONG></P>
! 7460: <P>
! 7461: To generate the translation of each section in a different file,the following
! 7462: rule can be associated with type <TT>Section</TT>.That rule uses the <A
! 7463: href="#varoutputfile"><TT>VarOutpuFile</TT> variable</A>defined above.</P>
! 7464: <PRE>
! 7465: Section:
! 7466: ChangeMainFile VarOutpuFile Before;
! 7467: </PRE>
! 7468: <P>
! 7469: If <TT>output.txt</TT>is the name of the output file specified whenstarting
! 7470: the translation program, translated sections are writtenin files
! 7471: <TT>output1.txt</TT>, <TT>output2.txt</TT>, etc.</P>
! 7472: </BLOCKQUOTE>
! 7473: </DIV>
! 7474:
! 7475: <DIV class="subsection">
! 7476: <H3><A name="setandadd">The <TT>Set</TT> and <TT>Add</TT> rules</A></H3>
! 7477:
! 7478: <P>
! 7479: The <TT>Set</TT> and <TT>Add</TT> rules are used for modifying the value of
! 7480: counters that have no <A href="#counters">counting function</A>. Only this
! 7481: type of counter can be used in the <TT>Set</TT> and <TT>Add</TT> rules.</P>
! 7482: <P>
! 7483: Both rules have the same syntax: after the keyword <TT>Set</TT> or
! 7484: <TT>Add</TT> appear the counter name and the value to assign to the counter
! 7485: (<TT>Set</TT> rule) or the value to be added to the counter (<TT>Add</TT>
! 7486: rule). The keyword <TT>Before</TT> or <TT>After</TT> can follo9w that value to
! 7487: indicate when the rule must be applied: before or after the element's content
! 7488: is translated. By default, <TT>Before</TT> is assumed. A semicolon terminates
! 7489: the rule.</P>
! 7490: <PRE>
! 7491: 'Set' CounterID InitValue [ Position ] ';' /
! 7492: 'Add' CounterID Increment [ Position ] ';'
! 7493: </PRE>
! 7494: </DIV>
! 7495:
! 7496: <DIV class="subsection">
! 7497: <H3><A name="order">Rule application order</A></H3>
! 7498:
! 7499: <P>
! 7500: The translator translates the elements which comprise the document in the
! 7501: order induced by the tree structure, except when the <TT>Get</TT> rule is used
! 7502: to change the order of translation. For each element, the translator first
! 7503: applies the rules specified for the element's type that must be applied before
! 7504: translation of the element's content (rules ending with the <TT>Before</TT>
! 7505: keyword or which have no position keyword). If several rules meet these
! 7506: criteria, the translator applies them in the order in where they appear in the
! 7507: translation schema.</P>
! 7508: <P>
! 7509: It then applies all <A href="#transattr">rules for the attributes</A> which
! 7510: the element has and which must be applied before the translation of the
! 7511: element's content (rules ending with the <TT>Before</TT> keyword or which have
! 7512: no position keyword). For one attribute value, the translator applies the
! 7513: rules in the order in which they are defined in the translation schema.</P>
! 7514: <P>
! 7515: The same procedure is followed with translation rules for specific
! 7516: presentations.</P>
! 7517: <P>
! 7518: Next, the element's content is translated, as long as a <TT>Remove</TT> rule
! 7519: does not apply.</P>
! 7520: <P>
! 7521: In the next step, the translator applies rules for the specific presentation
! 7522: of the element that are to be applied after translation of the content (rules
! 7523: which end with the <TT>After</TT> keyword). The rules for each type of
! 7524: presentation rule or each value are applied in the order in which the
! 7525: translation appear in the schema.</P>
! 7526: <P>
! 7527: Then, the same procedure is followed for translation rules for attributes of
! 7528: the element.</P>
! 7529: <P>
! 7530: Finally, the translator applies rules for the element which must be applied
! 7531: after translation of the element's content. These rules are applied in the
! 7532: order that they appear in the translation schema. When the translation of an
! 7533: element is done, the translator procedes to translate the following
! 7534: element.</P>
! 7535: <P>
! 7536: This order can be changed with the <TT>Attributes</TT> and
! 7537: <TT>Presentation</TT> options of the <A href="#create"><TT>Create</TT>
! 7538: rule</A>.</P>
! 7539: </DIV>
! 7540:
! 7541: <DIV class="subsection">
! 7542: <H3><A name="transattr">Translation of logical attributes</A></H3>
! 7543:
! 7544: <P>
! 7545: After the rules for the element types, the translation schema defines rules
! 7546: for attribute values. This section begins with the <TT>ATTRIBUTES</TT>
! 7547: keyword and is composed of a sequence of rule blocks each preceded by an
! 7548: attribute name and an optional value or value range.</P>
! 7549: <P>
! 7550: If the attribute's name appears alone before the rule block, the rule are
! 7551: applied to all element which have the attribute, no matter what value the
! 7552: attribute has. In this case, the attribute name is followed by a colon before
! 7553: the beginning of the rule block.</P>
! 7554: <P>
! 7555: The attribute's name can be followed by the name of an element type between
! 7556: parentheses. This says, as in presentation schemas, that the rule block which
! 7557: follows applies not to the element which has the attribute, but to its
! 7558: descendants of the type indicated between the parentheses.</P>
! 7559: <P>
! 7560: If values are given after the attribute name (or after the name of the element
! 7561: type), the rules are applied only when the attribute has the indicated values.
! 7562: The same attribute can appear several times, with different values and
! 7563: different translation rules. Attribute values are indicated in the same way
! 7564: as in <A href="#transcond">conditions</A> and are followed by a colon before
! 7565: the block of rules.</P>
! 7566: <P>
! 7567: The rule block associated with an attribute is either a simple rule or a
! 7568: sequence of rules delimited by the <TT>BEGIN</TT> and <TT>END</TT> keywords.
! 7569: Note that rules associated with attribute values cannot be conditional.</P>
! 7570: <P>
! 7571: Translation rules are not required for all attributes (or their values)
! 7572: defined in a structure schema. Only those attributes for which a particular
! 7573: action must be performed by the translator must have such rules. The rules
! 7574: that can be used are those described above, from <A
! 7575: href="#create"><TT>Create</TT></A> to <A
! 7576: href="#notrans"><TT>NoTranslation</TT></A>.</P>
! 7577: <PRE>
! 7578: AttrSeq = TransAttr < TransAttr > .
! 7579: TransAttr = AttrID [ '(' ElemID ')' ]
! 7580: [ RelatAttr ] ':' RuleSeq .
! 7581: AttrID = NAME .
! 7582: ElemID = NAME .
! 7583: </PRE>
! 7584: <BLOCKQUOTE class="example">
! 7585: <P>
! 7586: <STRONG>Example:</STRONG></P>
! 7587: <P>
! 7588: The structure defined the ``Language'' attribute which can take thevalues
! 7589: ``French'' and ``English''. To have the French parts of theoriginal document
! 7590: removed and prevent the translation of the leavesof the English parts, the
! 7591: following rules would be used:</P>
! 7592: <PRE>
! 7593: ATTRIBUTES
! 7594: Language=French :
! 7595: Remove;
! 7596: Language=English :
! 7597: NoTranslation;
! 7598: </PRE>
! 7599: </BLOCKQUOTE>
! 7600: </DIV>
! 7601:
! 7602: <DIV class="subsection">
! 7603: <H3><A name="prestrans">Translation of specific presentations</A></H3>
! 7604:
! 7605: <P>
! 7606: After the rules for attributes, the translation schema defines rules for the
! 7607: specific presentation. This section begins with the <TT>PRESENTATION</TT>
! 7608: keyword and is composed of a sequence of translation rule blocks each preceded
! 7609: by a presentation rule name, optionally accompanied by a part which depends on
! 7610: the particular presentation rule.</P>
! 7611: <P>
! 7612: Each of these translation rule blocks is applied when the translator operates
! 7613: on an element which has a specific presentation rule of the type indicated at
! 7614: the head of the block. Depending on the type of the specific presentation
! 7615: rule, it is possible to specify values of the presentation rule for which the
! 7616: translation rule block should be applied.</P>
! 7617: <P>
! 7618: There are three categories of the presentation rules:</P>
! 7619: <UL>
! 7620: <LI>rules taking numeric values: <TT>Size</TT>,
! 7621: <TT>Indent</TT>,<TT>LineSpacing</TT>, <TT>LineWeight</TT>,
! 7622: <LI>rules whose values are taken from a predefined list (i.e. whose typeis an
! 7623: enumeration): <TT>Adjust</TT>, <TT>Justify</TT>, <TT>Hyphenate,/TT>,
! 7624: <TT>Style</TT>, <TT>Font</TT>, <TT>UnderLine</TT>, <TT>Thickness</TT>,
! 7625: <TT>LineStyle</TT>,</TT>
! 7626: <LI>rules whose value is a name: <TT>FillPattern</TT>,
! 7627: <TT>Background</TT>,<TT>Foreground</TT>.
! 7628: </UL>
! 7629: <P>
! 7630: For presentation rules of the first category, the values which provoke
! 7631: application of the translation rules are indicated in the same manner as for
! 7632: <A href="#relattr">numeric attributes</A>. This can be either a unique value
! 7633: or range of values. For a unique value, the value (an integer) is simply
! 7634: preceded by an equals sign. Value ranges can be specified in one of three
! 7635: ways:</P>
! 7636: <UL>
! 7637: <LI>all values less than a given value (this value is preceded by a``less
! 7638: than'' sign (<TT><</TT>),
! 7639: <LI>all values greater than a given value (this value is preceded by
! 7640: a``greater than'' sign (<TT>></TT>),
! 7641: <LI>all values falling in an interval, bounds included. The rangeof values is
! 7642: then specified <TT>IN [</TT>Minimum <TT>..</TT>Maximum<TT>]</TT>,where Minimum
! 7643: and Maximum are integers.
! 7644: </UL>
! 7645: <P>
! 7646: All numeric values can be negative, in which case the integer ispreceded by a
! 7647: minus sign. All values must be given in typographerspoints.</P>
! 7648: <P>
! 7649: For presentation rules whose values are taken from a predefined list, the
! 7650: value which provokes application of the translation rules is simply indicated
! 7651: by the equals sign followed by the name of the value.</P>
! 7652: <P>
! 7653: For presentation rules whose values are names, the value which provokes the
! 7654: application of translation rules is simply indicated by the equals sign
! 7655: followed by the name of the value. The names of the fill patterns (the
! 7656: <TT>FillPattern</TT> rule) and of the colors (the <TT>Foreground</TT> and
! 7657: <TT>Background</TT> rules) used in Thot are the same as in the P language.</P>
! 7658: <PRE>
! 7659: PresSeq = PresTrans < PresTrans > .
! 7660: PresTrans = PresRule ':' RuleSeq .
! 7661: PresRule = 'Size' [ PresRelation ] /
! 7662: 'Indent' [ PresRelation ] /
! 7663: 'LineSpacing' [ PresRelation ] /
! 7664: 'Adjust' [ '=' AdjustVal ] /
! 7665: 'Justify' [ '=' BoolVal ] /
! 7666: 'Hyphenate' [ '=' BoolVal ] /
! 7667: 'Style' [ '=' StyleVal ] /
! 7668: 'Font' [ '=' FontVal ] /
! 7669: 'UnderLine' [ '=' UnderLineVal ] /
! 7670: 'Thickness' [ '=' ThicknessVal ] /
! 7671: 'LineStyle' [ '=' LineStyleVal ] /
! 7672: 'LineWeight' [ PresRelation ] /
! 7673: 'FillPattern' [ '=' Pattern ] /
! 7674: 'Background' [ '=' Color ] /
! 7675: 'Foreground' [ '=' Color ] .
! 7676:
! 7677: PresRelation = '=' PresValue /
! 7678: '>' [ '-' ] PresMinimum /
! 7679: '<' [ '-' ] PresMaximum /
! 7680: 'IN' '[' [ '-' ] PresIntervalMin '..'
! 7681: [ '-' ] PresIntervalMax ']' .
! 7682: AdjustVal = 'Left' / 'Right' / 'VMiddle' /
! 7683: 'LeftWithDots' .
! 7684: BoolVal = 'Yes' / 'No' .
! 7685: StyleVal = 'Bold' / 'Italics' / 'Roman' /
! 7686: 'BoldItalics' / 'Oblique' /
! 7687: 'BoldOblique' .
! 7688: FontVal = 'Times' / 'Helvetica' / 'Courier' .
! 7689: UnderLineVal = 'NoUnderline' / 'UnderLined' /
! 7690: 'OverLined' / 'CrossedOut' .
! 7691: ThicknessVal = 'Thick' / 'Thin' .
! 7692: LineStyleVal = 'Solid' / 'Dashed' / 'Dotted' .
! 7693: Pattern = NAME .
! 7694: Color = NAME .
! 7695: PresMinimum = NUMBER .
! 7696: PresMaximum = NUMBER .
! 7697: PresIntervalMin= NUMBER .
! 7698: PresIntervalMax= NUMBER .
! 7699: PresValue = [ '-' ] PresVal .
! 7700: PresVal = NUMBER .
! 7701: </PRE>
! 7702: <P>
! 7703: The <A name="prestransl">translation rules associated with specific
! 7704: presentation rules</A> can use the value of the specific presentation rule
! 7705: that causes them to be applied. This behavior is designated by the keyword
! 7706: <TT>Value</TT>. For numerically-valued presentation rules, the numeric value
! 7707: is produced. For other presentation rules, the name of the value is
! 7708: produced.</P>
! 7709: <P>
! 7710: It should be noted that modifications to the layout of the document's elements
! 7711: that are made using the combination of the control key and a mouse button will
! 7712: have no effect on the translation of the document.</P>
! 7713: <BLOCKQUOTE class="example">
! 7714: <P>
! 7715: <STRONG>Example:</STRONG></P>
! 7716: <P>
! 7717: Suppose that it is desirable to use the same font sizes as in thespecific
! 7718: presentation, but the font size must be between 10 and 18typographer's points.
! 7719: If font size is set in the translated documentby the string
! 7720: <TT>pointsize=n</TT>where <TT>n</TT>is the font size intypographer's points
! 7721: then the following rules will suffice:</P>
! 7722: <PRE>
! 7723: PRESENTATION
! 7724: Size < 10 :
! 7725: Create 'pointsize=10';
! 7726: Size in [10..18] :
! 7727: BEGIN
! 7728: Create 'pointsize=';
! 7729: Create Value;
! 7730: END;
! 7731: Size > 18 :
! 7732: Create 'pointsize=18';
! 7733: </PRE>
! 7734: </BLOCKQUOTE>
! 7735: </DIV>
! 7736:
! 7737: <DIV class="subsection">
! 7738: <H3><A name="texttrans">Recoding of characters, symbols and graphics</A></H3>
! 7739:
! 7740: <P>
! 7741: The coding of characters, graphical elements and symbols as defined in Thot
! 7742: does not necessarily correspond to what is required by an application to which
! 7743: a Thot document must be exported. Because of this the translator can recode
! 7744: these terminal elements of the documents structure. The last sections of a
! 7745: translation schema are intended for this purpose, each specifying the recoding
! 7746: rules for one type of terminal element.</P>
! 7747: <P>
! 7748: The recoding rules for character strings are grouped by alphabets. There is a
! 7749: group of rules for each alphabet of the Thot document that must be translated.
! 7750: Each such group of rules begins with the <TT>TEXTTRANSLATE</TT> keyword,
! 7751: followed by the specification of the alphabet to translate and the recoding
! 7752: rules, between the <TT>BEGIN</TT> and <TT>END</TT> keywords unless there is
! 7753: only one recoding rule for the alphabet. The specification of the alphabet is
! 7754: not required: by default it is assumed to the Latin alphabet (the ISO Latin-1
! 7755: character set).</P>
! 7756: <P>
! 7757: Each recoding rule is formed by a source string between apostrophes and a
! 7758: target string, also between apostrophes, the two strings being separated by
! 7759: the arrow symbol (<TT>-></TT>), formed by the ``minus'' and ``greater than''
! 7760: characters. The rule is terminated by a semi-colon.</P>
! 7761: <PRE>
! 7762: TextTransSeq = [ Alphabet ] TransSeq .
! 7763: Alphabet = NAME .
! 7764: TransSeq ='BEGIN' < Translation > 'END' ';' /
! 7765: Translation .
! 7766: Translation = Source [ '->' Target ] ';' .
! 7767: Source = STRING .
! 7768: Target = STRING .
! 7769: </PRE>
! 7770: <P>
! 7771: One such rule signifies that when the source string appears in a text leaf of
! 7772: the document being translated, the translator must replace it, in the
! 7773: translated document, with the target string. The source string and the target
! 7774: string can have different lengths and the target string can be empty. In this
! 7775: last case, the translator simply suppresses every occurrence of the source
! 7776: string in the translated document.</P>
! 7777: <P>
! 7778: For a given alphabet, the order of the rules is not important and has no
! 7779: significance because the T language compiler reorders the rules in ways that
! 7780: speed up the translator's work. The total number of recoding rules is limited
! 7781: by the compiler as is the maximum length of the source and target strings.</P>
! 7782: <P>
! 7783: The recoding rules for symbols and graphical elements are written in the same
! 7784: manner as the recoding rules for character strings. They are preceded,
! 7785: respectively, by the <TT>SYMBTRANSLATE</TT> and <TT>GRAPHTRANSLATE</TT> and so
! 7786: not require a specification of the alphabet. Their source string is limited to
! 7787: one character, since, in Thot, each symbol and each graphical element is
! 7788: represented by a single character. The symbol and graphical element codes are
! 7789: defined along with the <A href="#charcoding">non-standard character
! 7790: codes</A>.</P>
! 7791: <BLOCKQUOTE class="example">
! 7792: <P>
! 7793: <STRONG>Example:</STRONG></P>
! 7794: <P>
! 7795: In a translation schema producing documents destined for use with
! 7796: theL<SUP>A</SUP>T<SUB><BIG>E</BIG></SUB>X formatter, the Latin
! 7797: characters``é'' (octal code 351 in Thot) and ``è'' (octal code
! 7798: 350in Thot) must be converted to their representation
! 7799: inL<SUP>A</SUP>T<SUB><BIG>E</BIG></SUB>X:</P>
! 7800: <PRE>
! 7801: TEXTTRANSLATE Latin
! 7802: BEGIN
! 7803: '\350' -> '\`{e}'; { e grave }
! 7804: '\351' -> '\''{e}'; { e acute }
! 7805: END;
! 7806: </PRE>
! 7807: </BLOCKQUOTE>
! 7808: </DIV>
! 7809: </DIV>
! 7810: <HR>
! 7811: </DIV>
! 7812:
! 7813: <DIV class="chapter">
! 7814: <H1>Language grammars</H1>
! 7815:
! 7816: <P>
! 7817: This chapter gives the complete grammars of the languages of Thot. The
! 7818: grammars were presented and described in the preceding chapters, which also
! 7819: specify the semantics of the languages. This section gives only the
! 7820: syntax.</P>
! 7821:
! 7822: <DIV class="section">
! 7823: <H2>The M meta-language</H2>
! 7824:
! 7825: <P>
! 7826: The language grammars are all expressed in the same formalism, the M
! 7827: meta-language, which is defined in this section.</P>
! 7828: <PRE>
! 7829: { Any text between braces is a comment. }
! 7830: Grammar = Rule < Rule > 'END' .
! 7831: { The < and > signs indicate zero }
! 7832: { or more repetitions. }
! 7833: { END marks the end of the grammar. }
! 7834: Rule = Ident '=' RightPart '.' .
! 7835: { The period indicates the end of a rule }
! 7836: RightPart = RtTerminal / RtIntermed .
! 7837: { The slash indicates a choice }
! 7838: RtTerminal ='NAME' / 'STRING' / 'NUMBER' .
! 7839: { Right part of a terminal rule }
! 7840: RtIntermed = Possibility < '/' Possibility > .
! 7841: { Right part of an intermediate rule }
! 7842: Possibility = ElemOpt < ElemOpt > .
! 7843: ElemOpt = Element / '[' Element < Element > ']' /
! 7844: '<' Element < Element > '>' .
! 7845: { Brackets delimit optional parts }
! 7846: Element = Ident / KeyWord .
! 7847: Ident = NAME .
! 7848: { Identifier, sequence of characters
! 7849: KeyWord = STRING .
! 7850: { Character string delimited by apostrophes }
! 7851: END
! 7852: </PRE>
! 7853: </DIV>
! 7854:
! 7855: <DIV class="section">
! 7856: <H2>The S language</H2>
! 7857:
! 7858: <P>
! 7859: The S language is used to write structure schemas, which contain the generic
! 7860: logical structures of document and object classes. It is described here in
! 7861: the M meta-language.</P>
! 7862: <PRE>
! 7863: StructSchema = 'STRUCTURE' [ 'EXTENSION' ] ElemID ';'
! 7864: 'DEFPRES' PresID ';'
! 7865: [ 'ATTR' AttrSeq ]
! 7866: [ 'PARAM' RulesSeq ]
! 7867: [ 'STRUCT' RulesSeq ]
! 7868: [ 'EXTENS' ExtensRuleSeq ]
! 7869: [ 'ASSOC' RulesSeq ]
! 7870: [ 'UNITS' RulesSeq ]
! 7871: [ 'EXPORT' SkeletonSeq ]
! 7872: [ 'EXCEPT' ExceptSeq ]
! 7873: 'END' .
! 7874:
! 7875: ElemID = NAME .
! 7876: PresID = NAME .
! 7877:
! 7878: AttrSeq = Attribute < Attribute > .
! 7879: Attribute = AttrID '=' AttrType ';' .
! 7880: AttrType = 'INTEGER' / 'TEXT' /
! 7881: 'REFERENCE' '(' RefType ')' /
! 7882: ValueSeq .
! 7883: RefType = 'ANY' /
! 7884: [ FirstSec ] ElemID [ ExtStruct ] .
! 7885: ValueSeq = AttrVal < ',' AttrVal > .
! 7886: AttrID = NAME .
! 7887: FirstSec = 'First' / 'Second' .
! 7888: ExtStruct = '(' ElemID ')' .
! 7889: AttrVal = NAME .
! 7890:
! 7891: RulesSeq = Rule < Rule > .
! 7892: Rule = ElemID [ LocAttrSeq ] '='
! 7893: DefWithAttr ';' .
! 7894: LocAttrSeq = '(' 'ATTR' LocalAttr
! 7895: < ';' LocalAttr > ')' .
! 7896: LocalAttr = [ '!' ] AttrID [ '=' AttrType ] .
! 7897: DefWithAttr = Definition
! 7898: [ '+' '(' ExtensionSeq ')' ]
! 7899: [ '-' '(' RestrictSeq ')' ]
! 7900: [ 'WITH' FixedAttrSeq ] .
! 7901: ExtensionSeq = ExtensionElem < ',' ExtensionElem > .
! 7902: ExtensionElem = ElemID / 'TEXT' / 'GRAPHICS' /
! 7903: 'SYMBOL' / 'PICTURE' .
! 7904: RestrictSeq = RestrictElem < ',' RestrictElem > .
! 7905: RestrictElem = ElemID / 'TEXT' / 'GRAPHICS' /
! 7906: 'SYMBOL' / 'PICTURE' .
! 7907: FixedAttrSeq = FixedAttr < ',' FixedAttr > .
! 7908: FixedAttr = AttrID [ FixedOrModifVal ] .
! 7909: FixedOrModifVal= [ '?' ] '=' FixedValue .
! 7910: FixedValue = [ '-' ] NumValue / TextValue / AttrVal .
! 7911: NumValue = NUMBER .
! 7912: TextValue = STRING .
! 7913:
! 7914: Definition = BaseType [ LocAttrSeq ] / Constr /
! 7915: Element .
! 7916: BaseType = 'TEXT' / 'GRAPHICS' / 'SYMBOL' /
! 7917: 'PICTURE' / 'UNIT' / 'NATURE' .
! 7918: Element = ElemID [ ExtOrDef ] .
! 7919: ExtOrDef = 'EXTERN' / 'INCLUDED' /
! 7920: [ LocAttrSeq ] '=' Definition .
! 7921:
! 7922: Constr = 'LIST' [ '[' min '..' max ']' ] 'OF'
! 7923: '(' DefWithAttr ')' /
! 7924: 'BEGIN' DefOptSeq 'END' /
! 7925: 'AGGREGATE' DefOptSeq 'END' /
! 7926: 'CASE' 'OF' DefSeq 'END' /
! 7927: 'REFERENCE' '(' RefType ')' /
! 7928: 'PAIR' .
! 7929:
! 7930: min = Integer / '*' .
! 7931: max = Integer / '*' .
! 7932: Integer = NUMBER .
! 7933:
! 7934: DefOptSeq = DefOpt ';' < DefOpt ';' > .
! 7935: DefOpt = [ '?' ] DefWithAttr .
! 7936:
! 7937: DefSeq = DefWithAttr ';' < DefWithAttr ';' > .
! 7938:
! 7939: SkeletonSeq = SkeletonElem < ',' SkeletonElem > ';' .
! 7940: SkeletonElem = ElemID [ 'WITH' Contents ] .
! 7941: Contents = 'Nothing' / ElemID [ ExtStruct ] .
! 7942:
! 7943: ExceptSeq = Except ';' < Except ';' > .
! 7944: Except = [ 'EXTERN' ] [ FirstSec ] ExcTypeOrAttr ':'
! 7945: ExcValSeq .
! 7946: ExcTypeOrAttr = ElemID / AttrID .
! 7947: ExcValSeq = ExcValue < ',' ExcValue > .
! 7948: ExcValue = 'NoCut' / 'NoCreate' /
! 7949: 'NoHMove' / 'NoVMove' / 'NoMove' /
! 7950: 'NoHResize' / 'NoVResize' / 'NoResize' /
! 7951: 'NewWidth' / 'NewHeight' /
! 7952: 'NewHPos' / 'NewVPos' /
! 7953: 'Invisible' / 'NoSelect' /
! 7954: 'Hidden' / 'ActiveRef' /
! 7955: 'ImportLine' / 'ImportParagraph' /
! 7956: 'NoPaginate' / 'HighlightChildren' /
! 7957: 'ExtendedSelection' .
! 7958:
! 7959: ExtensRuleSeq = ExtensRule ';' < ExtensRule ';' > .
! 7960: ExtensRule = RootOrElem [ LocAttrSeq ]
! 7961: [ '+' '(' ExtensionSeq ')' ]
! 7962: [ '-' '(' RestrictSeq ')' ]
! 7963: [ 'WITH' FixedAttrSeq ] .
! 7964: RootOrElem = 'Root' / ElemID .
! 7965:
! 7966: END
! 7967: </PRE>
! 7968: </DIV>
! 7969:
! 7970: <DIV class="section">
! 7971: <H2>The P language</H2>
! 7972:
! 7973: <P>
! 7974: The P language is used to write presentation schemas, which define the
! 7975: graphical presentation rules to be applied to different classes of documents
! 7976: and objects. It is described here in the M meta-language.</P>
! 7977: <PRE>
! 7978: PresSchema = 'PRESENTATION' ElemID ';'
! 7979: [ 'VIEWS' ViewSeq ]
! 7980: [ 'PRINT' PrintViewSeq ]
! 7981: [ 'COUNTERS' CounterSeq ]
! 7982: [ 'CONST' ConstSeq ]
! 7983: [ 'VAR' VarSeq ]
! 7984: [ 'DEFAULT' ViewRuleSeq ]
! 7985: [ 'BOXES' BoxSeq ]
! 7986: [ 'RULES' PresentSeq ]
! 7987: [ 'ATTRIBUTES' PresAttrSeq ]
! 7988: [ 'TRANSMIT' TransmitSeq ]
! 7989: 'END' .
! 7990:
! 7991: ElemID = NAME .
! 7992:
! 7993: ViewSeq = ViewDeclaration
! 7994: < ',' ViewDeclaration > ';' .
! 7995: ViewDeclaration = ViewID [ 'EXPORT' ] .
! 7996: ViewID = NAME .
! 7997:
! 7998: PrintViewSeq = PrintView < ',' PrintView > ';' .
! 7999: PrintView = ViewID / ElemID .
! 8000:
! 8001: CounterSeq = Counter < Counter > .
! 8002: Counter = CounterID ':' CounterFunc ';' .
! 8003: CounterID = NAME .
! 8004: CounterFunc = 'RANK' 'OF' TypeOrPage [ SLevelAsc ]
! 8005: [ 'INIT' AttrID ] [ 'REINIT' AttrID ] /
! 8006: SetFunction < SetFunction >
! 8007: AddFunction < AddFunction >
! 8008: [ 'INIT' AttrID ] /
! 8009: 'RLEVEL' 'OF' ElemID .
! 8010: SLevelAsc = [ '-' ] LevelAsc .
! 8011: LevelAsc = NUMBER .
! 8012: SetFunction = 'SET' CounterValue 'ON' TypeOrPage .
! 8013: AddFunction = 'ADD' CounterValue 'ON' TypeOrPage .
! 8014: TypeOrPage = 'Page' [ '(' ViewID ')' ] /
! 8015: [ '*' ] ElemID .
! 8016: CounterValue = NUMBER .
! 8017:
! 8018: ConstSeq = Const < Const > .
! 8019: Const = ConstID '=' ConstType ConstValue ';' .
! 8020: ConstID = NAME .
! 8021: ConstType = 'Text' [ Alphabet ] / 'Symbol' /
! 8022: 'Graphics' / 'Picture' .
! 8023: ConstValue = STRING .
! 8024: Alphabet = NAME .
! 8025:
! 8026: VarSeq = Variable < Variable > .
! 8027: Variable = VarID ':' FunctionSeq ';' .
! 8028: VarID = NAME .
! 8029: FunctionSeq = Function < Function > .
! 8030: Function = 'DATE' / 'FDATE' /
! 8031: 'DocName' / 'DirName' /
! 8032: 'ElemName' / 'AttributeName' /
! 8033: ConstID / ConstType ConstValue /
! 8034: AttrID /
! 8035: 'VALUE' '(' PageAttrCtr ','
! 8036: CounterStyle ')' .
! 8037: PageAttrCtr = 'PageNumber' [ '(' ViewID ')' ] /
! 8038: [ MinMax ] CounterID / AttrID .
! 8039: CounterStyle = 'Arabic' / 'LRoman' / 'URoman' /
! 8040: 'Uppercase' / 'Lowercase' .
! 8041: MinMax = 'MaxRangeVal' / 'MinRangeVal' .
! 8042:
! 8043: BoxSeq = Box < Box > .
! 8044: Box = 'FORWARD' BoxID ';' /
! 8045: BoxID ':' ViewRuleSeq .
! 8046: BoxID = NAME .
! 8047:
! 8048: PresentSeq = Present < Present > .
! 8049: Present = [ '*' ] [ FirstSec ] ElemID ':'
! 8050: ViewRuleSeq .
! 8051: FirstSec = 'First' / 'Second' .
! 8052:
! 8053: PresAttrSeq = PresAttr < PresAttr > .
! 8054: PresAttr = AttrID [ '(' [ FirstSec ] ElemID ')' ]
! 8055: [ AttrRelation ] ':' ViewRuleSeq .
! 8056: AttrID = NAME .
! 8057: AttrRelation = '=' AttrVal /
! 8058: '>' [ '-' ] MinValue /
! 8059: '<' [ '-' ] MaxValue /
! 8060: 'IN' '[' [ '-' ] LowerBound '..'
! 8061: [ '-' ] UpperBound ']' /
! 8062: 'GREATER' AttrID /
! 8063: 'EQUAL' AttrID /
! 8064: 'LESS' AttrID .
! 8065: AttrVal = [ '-' ] EqualNum / EqualText / AttrValue .
! 8066: MinValue = NUMBER .
! 8067: MaxValue = NUMBER .
! 8068: LowerBound = NUMBER .
! 8069: UpperBound = NUMBER.
! 8070: EqualNum = NUMBER .
! 8071: EqualText = STRING .
! 8072: AttrValue = NAME .
! 8073:
! 8074: ViewRuleSeq = 'BEGIN' < RulesAndCond > < ViewRules >
! 8075: 'END' ';' /
! 8076: ViewRules / CondRules / Rule .
! 8077: RulesAndCond = CondRules / Rule .
! 8078: ViewRules = 'IN' ViewID CondRuleSeq .
! 8079: CondRuleSeq = 'BEGIN' < RulesAndCond > 'END' ';' /
! 8080: CondRules / Rule .
! 8081: CondRules = CondRule < CondRule >
! 8082: [ 'Otherwise' RuleSeq ] .
! 8083: CondRule = 'IF' ConditionSeq RuleSeq .
! 8084: RulesSeq = 'BEGIN' Rule < Rule > 'END' ';' / Rule .
! 8085:
! 8086: ConditionSeq = Condition < 'AND' Condition > .
! 8087: Condition = [ 'NOT' ] [ 'Target' ] ConditionElem .
! 8088: ConditionElem = 'First' / 'Last' /
! 8089: [ 'Immediately' ] 'Within' [ NumParent ]
! 8090: ElemID [ ExtStruct ] /
! 8091: ElemID /
! 8092: 'Referred' / 'FirstRef' / 'LastRef' /
! 8093: 'ExternalRef' / 'InternalRef' / 'CopyRef' /
! 8094: 'AnyAttributes' / 'FirstAttr' / 'LastAttr' /
! 8095: 'UserPage' / 'StartPage' / 'ComputedPage' /
! 8096: 'Empty' /
! 8097: '(' [ MinMax ] CounterName CounterCond ')' /
! 8098: CondPage '(' CounterID ')' .
! 8099: NumParent = [ GreaterLess ] NParent .
! 8100: GreaterLess = '>' / '<' .
! 8101: NParent = NUMBER.
! 8102: CounterCond = '<' MaxCtrVal / '>' MinCtrVal /
! 8103: '=' EqCtrVal /
! 8104: 'IN' '[' ['-'] MinCtrBound '..'
! 8105: ['-'] MaxCtrBound ']' .
! 8106: PageCond = 'Even' / 'Odd' / 'One' .
! 8107: MaxCtrVal = NUMBER .
! 8108: MinCtrVal = NUMBER .
! 8109: EqCtrVal = NUMBER .
! 8110: MaxCtrBound = NUMBER .
! 8111: MinCtrBound = NUMBER .
! 8112:
! 8113: Rule = PresParam ';' / PresFunc ';' .
! 8114: PresParam = 'VertRef' ':' HorizPosition /
! 8115: 'HorizRef' ':' VertPosition /
! 8116: 'VertPos' ':' VPos /
! 8117: 'HorizPos' ':' HPos /
! 8118: 'Height' ':' Extent /
! 8119: 'Width' ':' Extent /
! 8120: 'VertOverflow' ':' Boolean /
! 8121: 'HorizOverflow' ':' Boolean /
! 8122: 'LineSpacing' ':' DistOrInherit /
! 8123: 'Indent' ':' DistOrInherit /
! 8124: 'Adjust' ':' AlignOrInherit /
! 8125: 'Justify' ':' BoolInherit /
! 8126: 'Hyphenate' ':' BoolInherit /
! 8127: 'PageBreak' ':' Boolean /
! 8128: 'LineBreak' ':' Boolean /
! 8129: 'InLine' ':' Boolean /
! 8130: 'NoBreak1' ':' AbsDist /
! 8131: 'NoBreak2' ':' AbsDist /
! 8132: 'Gather' ':' Boolean /
! 8133: 'Visibility' ':' NumberInherit /
! 8134: 'Size' ':' SizeInherit /
! 8135: 'Font' ':' NameInherit /
! 8136: 'Style' ':' StyleInherit /
! 8137: 'Underline' ':' UnderLineInherit /
! 8138: 'Thickness' ':' ThicknessInherit /
! 8139: 'Depth' ':' NumberInherit /
! 8140: 'LineStyle' ':' LineStyleInherit /
! 8141: 'LineWeight' ':' DistOrInherit /
! 8142: 'FillPattern' ':' NameInherit /
! 8143: 'Background' ':' NameInherit /
! 8144: 'Foreground' ':' NameInherit .
! 8145: 'Content' ':' VarConst .
! 8146: PresFunc = Creation '(' BoxID ')' /
! 8147: 'Line' /
! 8148: 'NoLine' /
! 8149: 'Page' '(' BoxID ')' /
! 8150: 'Copy' '(' BoxTypeToCopy ')' .
! 8151:
! 8152: BoxTypeToCopy = BoxID [ ExtStruct ] /
! 8153: ElemID [ ExtStruct ] .
! 8154: ExtStruct = '(' ElemID ')' .
! 8155:
! 8156: Distance = [ Sign ] AbsDist .
! 8157: Sign = '+' / '-' .
! 8158: AbsDist = IntegerOrAttr [ '.' DecimalPart ]
! 8159: [ Unit ] .
! 8160: IntegerOrAttr = IntegerPart / AttrID .
! 8161: IntegerPart = NUMBER .
! 8162: DecimalPart = NUMBER .
! 8163: Unit = 'em' / 'ex' / 'cm' / 'mm' / 'in' / 'pt' /
! 8164: 'pc' / 'px' / '%' .
! 8165:
! 8166: HPos = 'nil' / VertAxis '=' HorizPosition
! 8167: [ 'UserSpecified' ] .
! 8168: VPos = 'nil' / HorizAxis '=' VertPosition
! 8169: [ 'UserSpecified' ] .
! 8170: VertAxis = 'Left' / 'VMiddle' / 'VRef' / 'Right' .
! 8171: HorizAxis = 'Top' / 'HMiddle' / 'HRef' / 'Bottom' .
! 8172:
! 8173: VertPosition = Reference '.' HorizAxis [ Distance ] .
! 8174: HorizPosition = Reference '.' VertAxis [ Distance ] .
! 8175: Reference = 'Enclosing' [ BoxTypeNot ] /
! 8176: 'Enclosed' [ BoxTypeNot ] /
! 8177: 'Previous' [ BoxTypeNot ] /
! 8178: 'Next' [ BoxTypeNot ] /
! 8179: 'Referred' [ BoxTypeNot ] /
! 8180: 'Creator' /
! 8181: 'Root' /
! 8182: '*' /
! 8183: BoxOrType .
! 8184: BoxOrType = BoxID /
! 8185: [ '*' ] [ FirstSec ] ElemID /
! 8186: 'AnyElem' / 'AnyBox' .
! 8187: BoxTypeNot = [ 'NOT' ] BoxOrType .
! 8188:
! 8189: Extent = Reference '.' HeightWidth
! 8190: [ Relation ] [ 'Min' ] /
! 8191: AbsDist [ 'UserSpecified' ] [ 'Min' ] /
! 8192: HPos / VPos .
! 8193: HeightWidth = 'Height' / 'Width' .
! 8194: Relation = '*' ExtentAttr '%' / Distance .
! 8195: ExtentAttr = ExtentVal / AttrID .
! 8196: ExtentVal = NUMBER .
! 8197:
! 8198: Inheritance = Kinship InheritedValue .
! 8199: Kinship = 'Enclosing' / 'GrandFather'/ 'Enclosed' /
! 8200: 'Previous' / 'Creator' .
! 8201: InheritedValue = '+' PosIntAttr [ 'Max' maximumA ] /
! 8202: '-' NegIntAttr [ 'Min' minimumA ] /
! 8203: '=' .
! 8204: PosIntAttr = PosInt / AttrID .
! 8205: PosInt = NUMBER .
! 8206: NegIntAttr = NegInt / AttrID .
! 8207: NegInt = NUMBER .
! 8208: maximumA = maximum / AttrID .
! 8209: maximum = NUMBER .
! 8210: minimumA = minimum / AttrID .
! 8211: minimum = NUMBER .
! 8212:
! 8213: AlignOrInherit = Kinship '=' / Alignment .
! 8214: Alignment = 'Left' / 'Right' / 'VMiddle' /
! 8215: 'LeftWithDots' .
! 8216:
! 8217: DistOrInherit = Kinship InheritedDist / Distance .
! 8218: InheritedDist = '=' / '+' AbsDist / '-' AbsDist .
! 8219:
! 8220: BoolInherit = Boolean / Kinship '=' .
! 8221: Boolean = 'Yes' / 'No' .
! 8222:
! 8223: NumberInherit = Integer / AttrID / Inheritance .
! 8224: Integer = NUMBER .
! 8225:
! 8226: LineStyleInherit= Kinship '=' / 'Solid' / 'Dashed' /
! 8227: 'Dotted' .
! 8228:
! 8229: SizeInherit = SizeAttr [ 'pt' ] / Kinship InheritedSize .
! 8230: InheritedSize = '+' SizeAttr [ 'pt' ]
! 8231: [ 'Max' MaxSizeAttr ] /
! 8232: '-' SizeAttr [ 'pt' ]
! 8233: [ 'Min' MinSizeAttr ] /
! 8234: '=' .
! 8235: SizeAttr = Size / AttrID .
! 8236: Size = NUMBER .
! 8237: MaxSizeAttr = MaxSize / AttrID .
! 8238: MaxSize = NUMBER .
! 8239: MinSizeAttr = MinSize / AttrID .
! 8240: MinSize = NUMBER .
! 8241:
! 8242: NameInherit = Kinship '=' / FontName .
! 8243: FontName = NAME .
! 8244: StyleInherit = Kinship '=' /
! 8245: 'Roman' / 'Bold' / 'Italics' /
! 8246: 'BoldItalics' / 'Oblique' / 'BoldOblique' .
! 8247: UnderLineInherit= Kinship '=' /
! 8248: 'NoUnderline' / 'Underlined' /
! 8249: 'Overlined' / 'CrossedOut' .
! 8250: ThicknessInherit= Kinship '=' / 'Thick' / 'Thin' .
! 8251:
! 8252: VarConst = ConstID / ConstType ConstValue /
! 8253: VarID / '(' FunctionSeq ')' /
! 8254: ElemID .
! 8255:
! 8256: Creation = Create [ 'Repeated' ] .
! 8257: Create = 'CreateFirst' / 'CreateLast' /
! 8258: 'CreateBefore' / 'CreateAfter' /
! 8259: 'CreateEnclosing' .
! 8260:
! 8261: TransmitSeq = Transmit < Transmit > .
! 8262: Transmit = TypeOrCounter 'To' ExternAttr
! 8263: '(' ElemID ')' ';' .
! 8264: TypeOrCounter = CounterID / ElemID .
! 8265: ExternAttr = NAME .
! 8266:
! 8267: END
! 8268: </PRE>
! 8269: </DIV>
! 8270:
! 8271: <DIV class="section">
! 8272: <H2>The T language</H2>
! 8273:
! 8274: <PRE>
! 8275: TransSchema = 'TRANSLATION' ElemID ';'
! 8276: [ 'LINELENGTH' LineLength ';' ]
! 8277: [ 'LINEEND' CHARACTER ';' ]
! 8278: [ 'LINEENDINSERT' STRING ';' ]
! 8279: [ 'BUFFERS' BufferSeq ]
! 8280: [ 'COUNTERS' CounterSeq ]
! 8281: [ 'CONST' ConstSeq ]
! 8282: [ 'VAR' VariableSeq ]
! 8283: 'RULES' ElemSeq
! 8284: [ 'ATTRIBUTES' AttrSeq ]
! 8285: [ 'PRESENTATION' PresSeq ]
! 8286: < 'TEXTTRANSLATE' TextTransSeq >
! 8287: [ 'SYMBTRANSLATE' TransSeq ]
! 8288: [ 'GRAPHTRANSLATE' TransSeq ]
! 8289: 'END' .
! 8290:
! 8291: LineLength = NUMBER .
! 8292:
! 8293: BufferSeq = Buffer < Buffer > .
! 8294: Buffer = BufferID [ '(' 'Picture' ')' ] ';' .
! 8295: BufferID = NAME .
! 8296:
! 8297: CounterSeq = Counter < Counter > .
! 8298: Counter = CounterID [ ':' CounterFunc ] ';' .
! 8299: CounterID = NAME .
! 8300: CounterFunc = 'Rank' 'of' ElemID [ SLevelAsc ]
! 8301: [ 'Init' AttrID ] /
! 8302: 'Rlevel' 'of' ElemID /
! 8303: 'Set' InitValue 'On' ElemID
! 8304: 'Add' Increment 'On' ElemID
! 8305: [ 'Init' AttrID ] .
! 8306: SLevelAsc = [ '-' ] LevelAsc .
! 8307: LevelAsc = NUMBER .
! 8308: InitValue = NUMBER .
! 8309: Increment = NUMBER .
! 8310: ElemID = NAME .
! 8311: AttrID = NAME .
! 8312:
! 8313: ConstSeq = Const < Const > .
! 8314: Const = ConstID '=' ConstValue ';' .
! 8315: ConstID = NAME .
! 8316: ConstValue = STRING .
! 8317:
! 8318: VariableSeq = Variable < Variable > .
! 8319: Variable = VarID ':' Function < Function > ';' .
! 8320: VarID = NAME .
! 8321: Function = 'Value' '(' CounterID [ ':' Length ]
! 8322: [ ',' CounterStyle ] ')' /
! 8323: 'FileDir' / 'FileName' / 'Extension' /
! 8324: 'DocumentName' / 'DocumentDir' /
! 8325: ConstID / CharString /
! 8326: BufferID / AttrID .
! 8327: Length = NUMBER .
! 8328: CounterStyle= 'Arabic' / 'LRoman' / 'URoman' /
! 8329: 'Uppercase' / 'Lowercase' .
! 8330: CharString = STRING .
! 8331:
! 8332: ElemSeq = TransType < TransType > .
! 8333: TransType = [ FirstSec ] ElemID ':' RuleSeq .
! 8334: FirstSec = 'First' / 'Second' .
! 8335: RuleSeq = Rule / 'BEGIN' < Rule > 'END' ';' .
! 8336: Rule = SimpleRule / ConditionBlock .
! 8337: ConditionBlock= 'IF' ConditionSeq SimpleRuleSeq .
! 8338: SimpleRuleSeq = 'BEGIN' < SimpleRule > 'END' ';' /
! 8339: SimpleRule .
! 8340:
! 8341: ConditionSeq = Condition [ 'AND' Condition ] .
! 8342: Condition = [ 'NOT' ] [ 'Target' ] Cond .
! 8343: Cond = CondElem / CondAscend .
! 8344: CondElem = 'FirstRef' / 'LastRef' /
! 8345: 'ExternalRef' /
! 8346: 'Defined' /
! 8347: 'Alphabet' '=' Alphabet /
! 8348: 'ComputedPage' / 'StartPage' /
! 8349: 'UserPage' / 'ReminderPage' /
! 8350: 'Empty' /
! 8351: 'FirstAttr' / 'LastAttr' .
! 8352: CondAscend = [ Ascend ] CondOnAscend .
! 8353: Ascend = '*' / 'Parent' / 'Ancestor' LevelOrType .
! 8354: LevelOrType = CondRelLevel / ElemID [ ExtStruct ] .
! 8355: CondRelLevel = NUMBER .
! 8356: CondOnAscend = 'First' / 'Last' /
! 8357: 'Referred' /
! 8358: [ 'Immediately' ] 'Within' [ NumParent ]
! 8359: ElemID [ ExtStruct ] /
! 8360: 'Attributes' /
! 8361: AttrID [ RelatAttr ] /
! 8362: 'Presentation' /
! 8363: PresRule /
! 8364: 'Comment' .
! 8365: NumParent = [ GreaterLess ] NParent .
! 8366: GreaterLess = '>' / '<' .
! 8367: NParent = NUMBER.
! 8368: Alphabet = NAME .
! 8369: RelatAttr = '=' Value /
! 8370: '>' [ '-' ] Minimum /
! 8371: '<' [ '-' ] Maximum /
! 8372: 'IN' '[' [ '-' ] MinInterval '..'
! 8373: [ '-' ] MaxInterval ']' .
! 8374: Value = [ '-' ] IntegerVal / TextVal / AttrValue .
! 8375: Minimum = NUMBER .
! 8376: Maximum = NUMBER .
! 8377: MinInterval = NUMBER .
! 8378: MaxInterval = NUMBER .
! 8379: IntegerVal = NUMBER .
! 8380: TextVal = STRING .
! 8381: AttrValue = NAME .
! 8382:
! 8383: SimpleRule = 'Create' [ 'IN' VarID ] Object
! 8384: [ Position ] ';' /
! 8385: 'Write' Object [ Position ] ';' /
! 8386: 'Read' BufferID [ Position ] ';' /
! 8387: 'Include' File [ Position ] ';' /
! 8388: 'Get' [ RelPosition ] ElemID
! 8389: [ ExtStruct ]
! 8390: [ Position ] ';' /
! 8391: 'Copy' [ RelPosition ] ElemID
! 8392: [ ExtStruct ]
! 8393: [ Position ] ';' /
! 8394: 'Use' TrSchema [ 'For' ElemID ] ';' /
! 8395: 'Remove' ';' /
! 8396: 'NoTranslation' ';' /
! 8397: 'NoLineBreak' ';' /
! 8398: 'ChangeMainFile' VarID [ Position ] ';' /
! 8399: 'Set' CounterID InitValue
! 8400: [ Position ] ';' /
! 8401: 'Add' CounterID Increment
! 8402: [ Position ] ';' .
! 8403:
! 8404: Object = ConstID / CharString /
! 8405: BufferID /
! 8406: VarID /
! 8407: '(' Function < Function > ')' /
! 8408: AttrID /
! 8409: 'Value' /
! 8410: 'Content' /
! 8411: 'Comment' /
! 8412: 'Attributes' /
! 8413: 'Presentation' /
! 8414: 'RefId' /
! 8415: 'PairId' /
! 8416: 'FileDir' / 'FileName' / 'Extension' /
! 8417: 'DocumentName' / 'DocumentDir' /
! 8418: [ 'Referred' ] ReferredObject .
! 8419: Position = 'After' / 'Before' .
! 8420:
! 8421: ReferredObject = VarID /
! 8422: ElemID [ ExtStruct ] /
! 8423: 'RefId' /
! 8424: 'DocumentName' / 'DocumentDir' .
! 8425:
! 8426: File = FileName / BufferID .
! 8427: FileName = STRING .
! 8428:
! 8429: RelPosition = 'Included' / 'Referred' .
! 8430: ExtStruct = '(' ElemID ')' .
! 8431:
! 8432: TrSchema = NAME .
! 8433:
! 8434: AttrSeq = TransAttr < TransAttr > .
! 8435: TransAttr = AttrID [ '(' ElemID ')' ]
! 8436: [ RelatAttr ] ':' RuleSeq .
! 8437:
! 8438: PresSeq = PresTrans < PresTrans > .
! 8439: PresTrans = PresRule ':' RuleSeq .
! 8440: PresRule = 'Size' [ PresRelation ] /
! 8441: 'Indent' [ PresRelation ] /
! 8442: 'LineSpacing' [ PresRelation ] /
! 8443: 'Adjust' [ '=' AdjustVal ] /
! 8444: 'Justify' [ '=' BoolVal ] /
! 8445: 'Hyphenate' [ '=' BoolVal ] /
! 8446: 'Style' [ '=' StyleVal ] /
! 8447: 'Font' [ '=' FontVal ] /
! 8448: 'UnderLine' [ '=' UnderLineVal ] /
! 8449: 'Thickness' [ '=' ThicknessVal ] /
! 8450: 'LineStyle' [ '=' LineStyleVal ] /
! 8451: 'LineWeight' [ PresRelation ] /
! 8452: 'FillPattern' [ '=' Pattern ] /
! 8453: 'Background' [ '=' Color ] /
! 8454: 'Foreground' [ '=' Color ] .
! 8455:
! 8456: PresRelation = '=' PresValue /
! 8457: '>' [ '-' ] PresMinimum /
! 8458: '<' [ '-' ] PresMaximum /
! 8459: 'IN' '[' [ '-' ] PresIntervalMin '..'
! 8460: [ '-' ] PresIntervalMax ']' .
! 8461: AdjustVal = 'Left' / 'Right' / 'VMiddle' /
! 8462: 'LeftWithDots' .
! 8463: BoolVal = 'Yes' / 'No' .
! 8464: StyleVal = 'Bold' / 'Italics' / 'Roman' /
! 8465: 'BoldItalics' / 'Oblique' /
! 8466: 'BoldOblique' .
! 8467: FontVal = 'Times' / 'Helvetica' / 'Courier' .
! 8468: UnderLineVal = 'NoUnderline' / 'UnderLined' /
! 8469: 'OverLined' / 'CrossedOut' .
! 8470: ThicknessVal = 'Thick' / 'Thin' .
! 8471: LineStyleVal = 'Solid' / 'Dashed' / 'Dotted' .
! 8472: Pattern = NAME .
! 8473: Color = NAME .
! 8474: PresMinimum = NUMBER .
! 8475: PresMaximum = NUMBER .
! 8476: PresIntervalMin= NUMBER .
! 8477: PresIntervalMax= NUMBER .
! 8478: PresValue = [ '-' ] PresVal .
! 8479: PresVal = NUMBER .
! 8480:
! 8481: TextTransSeq = [ Alphabet ] TransSeq .
! 8482: Alphabet = NAME .
! 8483: TransSeq = 'BEGIN' < Translation > 'END' ';' /
! 8484: Translation .
! 8485: Translation = Source [ '->' Target ] ';' .
! 8486: Source = STRING .
! 8487: Target = STRING .
! 8488: </PRE>
! 8489: </DIV>
! 8490: <HR>
! 8491: </DIV>
! 8492:
! 8493: <DIV class="chapter">
! 8494: <H1><A name="charcoding">Character coding</A></H1>
! 8495:
! 8496:
! 8497: <DIV class="section">
! 8498: <H2>Characters</H2>
! 8499:
! 8500: <P>
! 8501: The characters of the Latin alphabet follow the encoding defined in the ISO
! 8502: 8859-1 (ISO Latin 1) standard. The characters of the Greek alphabet follow
! 8503: the encoding defined by Adobe for its Symbol font (Adobe FontSpecific).</P>
! 8504: <P>
! 8505: Characters whose octal code is greater than 0200 are written in the form of
! 8506: their octal code preceded by a backslash character (``\''). For example, the
! 8507: French word Résumé is written <TT>R\351sum\351</TT>.</P>
! 8508: <P>
! 8509: To the ISO 8859-1 encoding six characters with the following codes have been
! 8510: added:<BR><TT>212</TT>: line break<BR><TT>240</TT>: sticky
! 8511: space<BR><TT>201</TT>: thin space<BR><TT>202</TT>: en space<BR></P>
! 8512: <P>
! 8513: The <TT>212</TT> character is a ``line break'' character which forces a line
! 8514: break. The <TT>240</TT> character is a ``sticky space'', which cannot be
! 8515: replaced by a line break.</P>
! 8516: </DIV>
! 8517:
! 8518: <DIV class="section">
! 8519: <H2><A name="symbolcoding">Symbols</A></H2>
! 8520:
! 8521: <P>
! 8522: The table below gives the codes for the symbols of Thot. Symbols can be used
! 8523: in presentation schemas constants and in transcoding rules of translation
! 8524: schemas. Each symbol is represented by a single character.</P>
! 8525: <UL>
! 8526: <LI><TT>r</TT>: a radical
! 8527: <LI><TT>i</TT>: a simple integral
! 8528: <LI><TT>c</TT>: a curvilinear integral
! 8529: <LI><TT>d</TT>: a double integral
! 8530: <LI><TT>t</TT>: a triple integral
! 8531: <LI><TT>S</TT>: the summation symbol
! 8532: <LI><TT>P</TT>: the product symbol
! 8533: <LI><TT>U</TT>: the union symbol
! 8534: <LI><TT>I</TT>: the intersection symbol
! 8535: <LI><TT>></TT>: a right arrow
! 8536: <LI><TT><</TT>: a left arrow
! 8537: <LI><TT>^</TT>: an up arrow
! 8538: <LI><TT>V</TT>: a down arrow
! 8539: <LI><TT>(</TT>: an opening parenthesis
! 8540: <LI><TT>)</TT>: a closing parenthesis
! 8541: <LI><TT>{</TT>: an opening brace
! 8542: <LI><TT>}</TT>: a closing brace
! 8543: <LI><TT>[</TT>: an opening bracket
! 8544: <LI><TT>]</TT>: a closing bracket
! 8545: </UL>
! 8546: </DIV>
! 8547:
! 8548: <DIV class="section">
! 8549: <H2>Graphical elements</H2>
! 8550:
! 8551: <P>
! 8552: The table below gives the codes for the graphical elements of Thot. These
! 8553: elements can be used in presentation schemas constants and in transcoding
! 8554: rules of translation schemas. Each graphical element is represented by a
! 8555: single character.</P>
! 8556: <UL>
! 8557: <LI><TT>c</TT>: an ellipse inscribed in the box
! 8558: <LI><TT>R</TT>: a rectangle which is the shape of the box
! 8559: <LI><TT>C</TT>: a rectangle with rounded corners
! 8560: <LI><TT>t</TT>: a horizontal line along the upper side of the box
! 8561: <LI><TT>h</TT>: a horizontal line as wide as the box and placed in its middle
! 8562: <LI><TT>b</TT>: a horizontal line along the lower side of the box
! 8563: <LI><TT>></TT>: a right arrow as long as the box's width and in its middle
! 8564: <LI><TT>></TT>: a left arrow as long as the box's width and in its middle
! 8565: <LI><TT>l</TT>: a vertical line on the left side of the box
! 8566: <LI><TT>v</TT>: a vertical line as tall as the box and placed in its middle
! 8567: <LI><TT>r</TT>: a vertical line on the right side of the box
! 8568: <LI><TT>^</TT>: an up arrow as tall as the box and in its middle
! 8569: <LI><TT>V</TT>: a down arrow as tall as the box and in its middle
! 8570: <LI><TT>/</TT>: The southwest/northeast diagonal of the box
! 8571: <LI><TT>\</TT>: the northwest/southeast diagonal of the box
! 8572: <LI><TT>O</TT>: The northwest/southeast diagonal of the box with anarrowhead
! 8573: at the top
! 8574: <LI><TT>e</TT>: The northwest/southeast diagonal of the box with anarrowhead
! 8575: at the bottom
! 8576: <LI><TT>E</TT>: The southwest/northeast diagonal of the box with anarrowhead
! 8577: at the top
! 8578: <LI><TT>o</TT>: The southwest/northeast diagonal of the box with anarrowhead
! 8579: at the bottom
! 8580: <LI><TT>space</TT>: a transparent element
! 8581: <LI><TT>P</TT>: a rectangle with round corners and a horizontal barat the top
! 8582: <LI><TT>Q</TT>: an ellipse with a horizontal bar at the top
! 8583: <LI><TT>L</TT>: a lozenge
! 8584: <LI><TT>W</TT>: the upper right corner
! 8585: <LI><TT>X</TT>: the lower right corner
! 8586: <LI><TT>Y</TT>: the lower left corner
! 8587: <LI><TT>Z</TT>: the upper left corner
! 8588: <LI><TT>p</TT>: a polygon
! 8589: <LI><TT>S</TT>: an open broken line
! 8590: <LI><TT>N</TT>: an open broken line with an arrow head at start
! 8591: <LI><TT>U</TT>: an open broken line with an arrow head at the end
! 8592: <LI><TT>M</TT>: an open broken line with two arrow heads
! 8593: <LI><TT>s</TT>: a closed curve
! 8594: <LI><TT>B</TT>: an open curve
! 8595: <LI><TT>F</TT>: an open curve with an arrow head at start
! 8596: <LI><TT>A</TT>: an open curve with an arrow head at the end
! 8597: <LI><TT>D</TT>: an open curve with two arrow heads
! 8598: </UL>
! 8599: </DIV>
! 8600: </DIV>
! 8601: </BODY>
! 8602: </HTML>
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