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| author | Karl Berry <karl@freefriends.org> | 2006-01-09 00:46:32 +0000 |
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| committer | Karl Berry <karl@freefriends.org> | 2006-01-09 00:46:32 +0000 |
| commit | 71c5ce4be7e36bdc6bdda98641bc9368e28223ad (patch) | |
| tree | 26b8ff85e42869ed572b133f6f3ac78ae4b462f7 /Master/texmf-dist/doc/xmltex/base/manual.xml | |
| parent | 5dc602d16c5be2fd035b254ca23484a90aebd6dc (diff) | |
doc xmltex
git-svn-id: svn://tug.org/texlive/trunk@82 c570f23f-e606-0410-a88d-b1316a301751
Diffstat (limited to 'Master/texmf-dist/doc/xmltex/base/manual.xml')
| -rw-r--r-- | Master/texmf-dist/doc/xmltex/base/manual.xml | 793 |
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diff --git a/Master/texmf-dist/doc/xmltex/base/manual.xml b/Master/texmf-dist/doc/xmltex/base/manual.xml new file mode 100644 index 00000000000..aec2851b949 --- /dev/null +++ b/Master/texmf-dist/doc/xmltex/base/manual.xml @@ -0,0 +1,793 @@ +<?xml version="1.0"?> + +<!DOCTYPE TEI.2 SYSTEM "http://www.oucs.ox.ac.uk/dtds/tei-oucs.dtd" [ + + <!NOTATION URL SYSTEM "" > + <!ENTITY lppl SYSTEM "http://www.latex-project.org/lppl.txt" NDATA URL> + + <!ENTITY ldots "…"> + + <!ENTITY TeX "TeX"> + <!ENTITY LaTeX "LaTeX"> + +]> +<TEI.2> + <teiHeader> + <fileDesc> + <titleStmt> + <title>xmltex</title> + </titleStmt> + <publicationStmt> + <availability> + <p> + This file is distributed under the LaTeX Project Public License + (LPPL) as found at <xptr doc="lppl"/>. + Either version 1.0, or at your option, any later version. + </p> + </availability> + </publicationStmt> + <sourceDesc> + <p></p> + </sourceDesc> + </fileDesc> + <profileDesc> + </profileDesc> + <revisionDesc> + <list> + <head></head> + <item><date>January 24th 2000</date> + <name>David Carlisle</name>Updated)</item> + <item><date>January 19th 2000</date> + <name>David Carlisle</name>Updated)</item> + <item><date>January 18th 2000</date> + <name>David Carlisle</name>Updated)</item> + <item><date>January 15th 2000</date> + <name>David Carlisle</name>Updated)</item> + <item><date>January 10th 2000</date> + <name>Sebastian Rahtz</name>corrections</item> + <item><date>January 10th 2000</date> + <name>David Carlisle</name>Updated (in XML)</item> + <item><date>January 6th 2000</date> + <name>Sebastian Rahtz</name>Converted to TEI XML</item> + <item><date>January 6th 2000</date> + <name>David Carlisle</name>written in LaTeX</item> + </list> + </revisionDesc> + </teiHeader> + <text> +<front> + <docTitle> + <titlePart type="main">xmltex: A non validating (and not 100% + conforming) namespace aware XML parser implemented in &TeX;</titlePart> + </docTitle> + <docDate>Date: 2000-01-24</docDate> + <docAuthor rend="email">davidc@nag.co.uk</docAuthor> + <docAuthor>David Carlisle</docAuthor> +</front> +<body> +<div id="intro"> +<head>Introduction</head> +<p> +xmltex implements +a non validating parser for documents matching the +W3C XML Namespaces Recommendation. + + +The system may just be used to parse the file (expanding entity +references and normalising namespace declarations) in which case it +records a trace of the parse on the terminal. Normally however the +information from the parse is used to trigger &TeX; typesetting code. +Declarations (in &TeX; syntax) are provided as part of xmltex to +associate &TeX; code with the start and end of each XML element, +attributes, processing instructions, and with unicode character data. +</p> +</div> + +<div> +<head>Installation</head> +<p>The xmltex parser itself does not require &LaTeX;. It may be loaded +into initex to produce a format capable of parsing XML files. However +such a format would have no convenient commands for typesetting, and +so normally xmltex will be used on top of an existing format, normally +&LaTeX;. In this section we assume that the document to be +processed is called <code>document.xml</code>. +</p> +<div> +<head>Using xmltex as an input to the &LaTeX; command</head> +<p>&LaTeX; requires a document in &TeX; syntax, not XML. To process +<code>document.xml</code>, first produce a two line file called +<code>document.tex</code> of the following form: +<eg> +\def\xmlfile{document.xml} +\input xmltex.tex +</eg> + +Do <emph>not</emph> put any other commands in this file!</p> +<p>You may then process the document with either of the commands: +<code>latex document</code> or <code>latex document.tex</code> +or the equivalent procedure in your &TeX; environment. +</p> +</div> +<div> +<head>Using xmltex as a &TeX; format built on &LaTeX;</head> +<p> +You may prefer to set up xmltex as a format in its own right. +This may speed things up slightly (as <code>xmltex.tex</code> does not +have to be read each time) but more importantly perhaps it allows the +XML file to be processed directly without needing to make the +<code>.tex</code> wrapper.</p> +<p>To make a format you will need a command such as the following, +depending on your &TeX; system. +<eg> +initex &latex xmltex +initex \&latex xmltex +tex -ini &latex xmltex +tex -ini \&latex xmltex +</eg></p> +<p>This will produce a format file <code>xmltex.fmt</code>. You should then +be able to make a <code>xmltex</code> command by copying the way the +<code>latex</code> command is defined in terms of +<code>latex.fmt</code>. Depending on the &TeX; system, this might be a +symbolic link, or a shell script, or batch file, or a configuration +option in a setup menu. + +</p> +</div> +<div> +<head> Making an xmltex format `from scratch'</head> +<p> +Whilst it may be convenient to build an xmltex format as above, starting +from the &LaTeX; format. You may prefer to instead work with an initex +with no existing format file. Even if you wish to use a standard &LaTeX; +it may be preferable to make a &TeX; input file that first inputs +<code>latex.ltx</code> then <code>xmltex.tex</code>. In particular this +will allow you to have a different hyphenation and language +customisation for xmltex than for &LaTeX;. Many of the features of +the language support in &LaTeX; are related to modifying the input +syntax to be more convenient. Such changes are not needed in xmltex as +the input syntax is always XML. Some language files may change the +meaning of such characters as < which would break the xmltex parser. +Also, rather than using <code>latex.ltx</code> you could in principle +use a modified <code>docstrip</code> install file and produce a +`cut down' latex that did not have features that are not going to be +used in xmltex. +</p> +<p> +Unfortunately the support for this method of building xmltex (and access +to non English hyphenation generally) is not fully designed and totally +undocumented.</p> +</div> +</div> +<div> +<head>Using xmltex</head> +<p> +xmltex by default `knows' nothing about any particular type of XML +file, and so needs to load external files containing specific +information. This section describes how the information in the XML +file determines which files will be loaded. + +<list type="ordered"> +<item> If the file begins with a Byte Order Mark, the default encoding + is set to utf-16. Otherwise the default encoding is utf-8. +</item> +<item> If (after an optional BOM) the document begins with an XML + declaration that specifies an encoding, this encoding will be used, + otherwise the default encoding will be used. A file with name of the + form <emph>encoding</emph><code>.xmt</code> will be loaded that maps the + requested encoding to Unicode positions. (It is an error if this + file does not exist for the requested encoding.) +</item> +<item> If the document has a <code>DOCTYPE</code> declaration that includes + a local subset then this will be parsed. If any external DTD entity + is referenced (by declaring and then referencing a parameter entity) + then the SYSTEM and PUBLIC identifiers of this entity will be looked + up in a catalogue (to be described below). If either identifier is + known in the catalogue the corresponding xmltex package (often with + <code>.xmt</code> extension) will be loaded. +</item> +<item> After any local subset has been processed, if the DOCTYPE + specifies an external entity, the PUBLIC and/or SYSTEM identifiers + of the external dtd file will be similarly looked up, and a + corresponding xmltex file loaded if known. +</item> +<item> As each element is processed, it may be `known' to xmltex by + virtue of one of the packages loaded, or it may be unknown. If it is + unknown then if it is in a declared namespace, the namespace URI + (not the prefix) is looked up in the xmltex catalogue. If the + catalogue specifies an xmltex package for this namespace it will be + loaded. If the element is not in a namespace, then the element name + will be looked up in the catalogue. +</item> +<item> If after all these steps the element is still unknown then + depending on the configuration setting either a warning or an error + will be displayed. (Currently only warning implemented.) +</item> +</list> +</p> +<div><head>The xmltex Catalogue</head> +<p>As discussed above, xmltex requires a mapping between PUBLIC and +SYSTEM identifiers, namespace URI, and element names, to files of +&TeX; code. This mapping is implemented by the following commands: +<eg> +<code>\NAMESPACE</code>{<emph>URI</emph>}{<emph>xmt-file</emph>} +<code>\PUBLIC</code>{<emph>FPI</emph>}{<emph>file</emph>} +<code>\SYSTEM</code>{<emph>URI</emph>}{<emph>file</emph>} +<code>\NAME</code>{<emph>element-name</emph>}{<emph>xmt-file</emph>} +<code>\XMLNS</code>{<emph>element-name</emph>}{<emph>URI</emph>} +</eg> +As described above, if the first argument of one of these commands +matches the string specified in the XML source file, the corresponding +&TeX; commands in the file specified in the second argument are +loaded. The PUBLIC and SYSTEM catalogue entries may also be used +to control which XML files should be input in response to external +entity references. The <code>\XMLNS</code> is rather different, +if an element in the null namespace does not have any definition +attatched to it, this declaration forces the default namespace to the +given URI. The catalogue lookup is then repeated. This allows for +example documents beginning <code><html></code> to be coerced into +the xhtml namespace.</p> +<p>These commands may be placed in a configuration file, either +<code>xmltex.cfg</code>, in which case they apply to all documents, +or in a configuration file `<code>\jobname.cfg</code>' (eg +<code>document.cfg</code> in the example in the Introduction) in which +case the commands just apply to the specified document. +</p> +</div> + +<div> +<head>Configuring xmltex</head> +<p>In addition to the `catalogue' commands described earlier there are +other commands that may be placed in the configuration files. + +<list type="unordered"> +<item> <p><code>\xmltraceonly</code></p> +<p> This stops xml from trying to typeset the + document. The external files specified in the catalogue are still + loaded, so that the trace may report any elements for which no code + is defined, but no actual typesetting takes place. In the event of + unknown errors it is always worth using xmltex in this mode to + isolate any problems.</p> +<p>It may be noted that if an xmltex format is built just using initex +without any typesetting commands, the resulting format should still +be able to parse any XML file if xmltex.cfg just specifies +<code>\xmltraceonly</code> and \jobname.cfg is empty.</p> +</item> +<item> <p><code>\xmltraceoff</code></p> +<p>By default xmltex provides a trace of its XML parse, displaying + each element begin and end. This command used in xmltex.cfg or + `\jobname.cfg' will stop this trace being produced.</p> +</item> + +<item><p> <code>\inputonce</code>{<emph>xmt-file</emph>}</p> +<p>The catalogue entries specify that + certain files should be loaded if XML constructs are met. + Alternatively the files may just always be loaded. The system will + ignore any later requests to load. This is especially useful if an + xmltex format is being made.</p> +</item> +<item><p><code>\UnicodeCharacter</code>{<emph>hex-or-dec</emph>}{<emph>tex-code</emph>}</p> +<p>The first argument specifies a unicode character number, in the same +format as used for XML character entities, namely either a decimal +number, or an upper case Hex number preceded by a lower case +`<code>x</code>'.</p> +<p>The second argument specifies arbitrary &TeX; code to be used when +typesetting this character. Any code in the XML +range may be specified (ie up to x10FFFF). Although codes in the +`ASCII' range, below 128, may be specified, the definitions supplied +for such characters will not be default be used. The definition will +howeverbe stored and used if the character is activated using the +command described below.</p> +</item> +<item> <p><code>\ActivateASCII</code>{<emph>hex-or-dec</emph>}</p> +<p>The argument to this command should be a number less than 128. +If a character us activated by this command in a configuration file +then any special typesetting instructions specified for the character +will be executed whenever the character appears as character data.</p> +<p>Some ASCII characters are activated by default. The list is +essentially those characters with special meanings to either &TeX; or +XML.</p> +</item> + +</list> +</p> +<p> +If a format is being made, there are essentially two copies of +<code>xmltex.cfg</code> that may play a role. The configuration file +input when the format is made will control catalogue entries and +packages built into the format. A possibly different +<code>xmltex.cfg</code> may be used in the input path of `normal' &TeX;, +this will then be used for additional information loaded each run.</p> +<p>In either case, a separate configuration file specific to the given +XML document may also be used (which is loaded immediately after +<code>xmltex.cfg</code>). +</p> +</div> +</div> + +<div id="stopping"> +<head>Stopping xmltex</head> +<p>In tracing mode, xmltex will stop after the end of the document +element has been processed. In the normal processing mode xmltex +does not currently automatically stop &TeX; processing. After +the document has completed &TeX; will move to the interactive +<code>*</code> prompt (from which you might want to exit with +<code><![CDATA[<?xmltex stop?>]]></code>). Normally the +end code specified for the document element should execute +<code>\end{document}</code> and so stop processing and avoid the +<code>*</code> prompt. +</p> +</div> + +<div> +<head>xmltex package files</head> +<p> +xmltex package files are the link between the XML markup and &TeX; +typesetting code. They are written in &TeX; (rather than XML) syntax +and may load directly or indirectly other files, including &LaTeX; +class and package files. For example a file loaded for a particular +document type may directly execute <code>\LoadClass{article}</code>, or +alternatively it may cause some XML element in the document to +execute <code>\documentclass{article}</code>. In either case the document will +suffer the dubious benefit of being formatted based on the style +implemented in <code>article.cls</code>. Beware though that the package +files may be loaded at strange times, the first time a given namespace +is declared in a document, and so the code should be written to work +if loaded inside a local group.</p> +<p>Characters in xmltex package files have their normal &LaTeX; meanings +except that line endings are ignored so that you do not need to add +a % to the end of lines in macro code. Unlike fd file conventions, other +white space is <emph>not</emph> ignored.</p> +<p>The available commands are: + +<list type="unordered"> +<item><p><code>\FileEncoding</code>{<emph>encoding</emph>}</p> +<p>This is the analogue for &TeX; syntax files of the encoding specification +in the XML or text declaration of XML files. If it is not specified the +file will be assumed to be in UTF-8.</p> +</item> + +<item><p><code>\DeclareNamespace</code>{<emph>prefix</emph>}{<emph>URI</emph>}</p> +<p>This declares a prefix to be used <emph>in this file</emph> for referring to +elements in the specified namespace. If the prefix is empty then this +declares the default namespace (otherwise, unprefixed element names +refer to elements that are not in a namespace).</p> +<p>Note that the elements in the XML document instance may use a +different prefix, or no prefix at all to access this namespace. +In order to resolve these different prefixes for the same namespace, +each time a namespace is encountered for the first time (either +by <code>\DeclareNamespace</code> in a preloaded package, or in a namespace +declaration in the XML instance) then it is allocated a new number +and any further namespace declaration for the same URI just locally +associates a prefix with this number. It is these numbers that are +displayed when the XML trace of the parse of the document is shown, +and also if any element is written out to an external file it will +have a normalised prefix of a number whichever prefix it had +originally. (Numeric prefixes are not legal XML, but this is an +advantage, it ensures these internal forms can not clash with any +prefix actually used in the document.)</p> +<p>Three namespaces are predeclared. The null namespace (0), the XML +namespace (<code>http://www.w3.org/1998/xml</code>) (1) which is predeclaed +with prefix <code>xml</code> as specified in the Namespace Recommendation, +and the xmltex namespace +(<code>http://www.dcarlisle.demon.co.uk/xmltex</code>) (2) which is not +given a default prefix, but may be used to have XML syntax for some +internal commands (eg to have .aux files fully in XML, currently they +are a hybrid mixture of some &TeX; and some XML syntax). +</p> +</item> +<item><p> + <code>\XMLelement</code>{<emph>element-qname</emph>}{<emph>attribute-spec</emph>} +{<emph>begin-code</emph>}{<emph>end-code</emph>}</p> +<p> This is similar to a &LaTeX; <code>\newenvironment</code> command.</p> +<p> Declare the code to execute at the start and end of each instance of +this element type. This code will be executed in a local group (like a +&LaTeX; environment). The second argument declares a list of attributes +and their default values using the <code>\XMLattribute</code> command +described below. +</p> +</item> +<item><p> + <code>\XMLelement</code>{<emph>element-qname</emph>} +{<emph>attribute-spec</emph>} +<code>{\xmlgrab}</code>{<emph>end-code</emph>}</p> +<p> A special case of the above command (which may be better made into a + separate declaration) is to make the <emph>start-code</emph> just be the command + <code>\xmlgrab</code>. In this case the <emph>end-code</emph> has access to the + element content (in XML syntax) as <code>#1</code>. This content isn't + literally the same as the original document, namespaces, white space + and attribute quote symbols will all have been normalised. +</p> +</item> +<item> <p> + <code>\XMLattribute</code>{<emph>attribute-qname</emph>} +{<emph>command-name</emph>}{<emph>default</emph>}</p> +<p>This command may only be used in the argument to +<code>\XMLelement</code>. + The first argument specifies the name of an attribute (using any + namespace prefixes current for this package file, which need not + be the same as the prefixes used in the document). + The second argument gives a &TeX; command name that will be used to + access the value of this attribute in the begin and end code for the + element. (Note using &TeX; syntax here provides a name independednt of + the namespace declarations that are in scope when this code is executed). + The third argument provides a default value that wil be used if the +attribute is not used on an instance of this element. + </p> +<p>The special token <code>\inherit</code> may be used which will cause +the command to have a value set in an ancestor element if this element +does not specify any value.</p> +<p>If a &TeX; token such as <code>\relax</code> is used as the default +the element code may distinguish the case that the attribute is not used +in the document.</p> +</item> +<item> <p> + <code>\XMLnamespaceattribute</code> +{<emph>prefix</emph>}{<emph>attribute-qname</emph>} +{<emph>command-name</emph>}{<emph>default</emph>}</p> +<p>This command is similar to <code>\XMLattribute</code> + but is used at the top level of the package file, not in the argument +to <code>\XMLelement</code>. It is equivalent to specifying the +attribute in <emph>every</emph> element in the namespace specified by +the first argument. As usual the prefix (which may be {} to denote the +default namespace) refers to the namespace declarations in the xmltex +package: the prefixes used in the document may be different.</p> +</item> + +<item><p><code>\XMLentity</code>{<emph>name</emph>}{<emph>code</emph>}</p> +<p>Declare an (internal parsed) entity, this is equivalent to a +<code><![CDATA[<!ENTITY]]></code> declaration, except that the +replacement text is specified in &TeX; syntax.</p> +</item> + +<item><p><code>\XMLname</code>{<emph>name</emph>}{<emph>command-name</emph>}</p> +<p>Declare the &TeX; command to hold the (normalised, internal form) of +the XML name given in the first argument. This allows the code specified in +<code>\XMLelement</code> to refer to XML element names without knowing +the encodings or namespace prefixes used in the document. Of particular +use might be to compare such a name with <code>\ifx\XML@parent</code> +which will allow element code to take different actions depending on +the parent of the current element.</p> +</item> + + +<item><p><code>\XMLstring</code>{<emph>command-name</emph>}<><emph>XML Data</emph></></p> +<p>This saves the XML fragment as the &TeX; command given in the first +argument. It may be particularly useful for redefining `fixed strings' +that are generated by &LaTeX; document classes to use any special +typesetting rules specified for individual characters.</p> +</item> + + +</list> + +</p> +</div> +<div> +<head>XML processing</head> +<p> +xmltex tries as far as possible to be a fully conforming non +validating parser. It fails in the following respects. +<list type="unordered"> +<item> Error reporting is virtually non existent. Names are not checked + against the list of allowed characters, and various other + constraints are not enforced. +</item> +<item><p> A non validating parser is not forced to read external dtd + entities (and this one does not) It is obliged to read the local + subset and process entity definitions and attribute declarations. + Entity declarations are reasonably well handled: External parameter + entities are handled as above, loading a corresponding xmltex file + if known. External entities are similarly processed, inputting + the XML file, a difference in this case is that if the entity is not + found in the catalogue, the SYSTEM identifier will be used directly + to <code>\input</code> as often this is a local file reference. Internal + parsed entities and parameter entities are essentially treated as + &TeX; macros, and nonparsed entities are saved along with their + NDATA type, for use presumably by <code>\includegraphics</code>.</p> +<p> What is not currently done, but mandated by the XML 1.0 + Recommendation is that default attributes are read from the internal + subset. (This might be added later.)</p> +</item> +<item><p> Support for encodings depends on having an encoding mapping + file. Any 8bit encoding that matches Unicode for the first 127 positions + may be used by making a trivial mapping file. (The one for latin1 + looks over complicated as it programs a loop rather than having 127 + declarations saying that latin1 and Unicode are identical in this + range).</p> +<p> UTF-8 is supported, but support for UTF-16 is minimal. Currently + only latin-1 values work: (In this range UTF-16 is just latin-1 with + a null byte inserted after (or before, depending on endedness) + each latin-1 byte. The UTF-16 implementation just ignores this null + byte then processes as for latin-1. Probably the first few 8bit + pages could be similarly supported by making the low ascii control + characters activate UTF-16 processing but this will never be + satisfactory using a standard &TeX;. Hopefully a setup for a 16bit + &TeX; such as Omega will correct this.</p> +</item> +</list> + +</p> +</div> +<div> +<head>Accessing &TeX;</head> +<p>In theory you should be able to control the document just be suitable +code specified by <code>\XMLelement</code> and friends, but sometimes it may be +necessary to `tweak' the output by placing commands directly in the +source.</p> +<p>Two mechanisms are availalable to do this. +<list type="unordered"> +<item><p> Using the xmltex namespace. The xmltex namespace conatins a + small (currently empty) set of useful &TeX; constructs that are + accessed by XML syntax. For example if xmltex provides a mechanism + for having XML (rather than &LaTeX;) syntax toc files, it will need + an analogue of <code>\contentsline</code> which might be an element + accessed by <gi>xmltex:contentsline</gi>&ldots; where the xmltex + prefix is declared on this or a parent element to be + <code>xmlns:xmltex="http://www.dcarlisle.demon.co.uk/xmltex"</code>.</p> +<p> As the xmltex namespace is declared but currently empty, a more + useful variant of this might be:</p> +</item> +<item> Declare your own namespace for &TeX; tweaks, and load a suitable + package file that attatches &TeX; code to the elements in this + namespace (or at least specify the correspondence between the + namespace and the package using <code>\NAMESPACE</code>). + For instance if you put <gi>clearpage xmlns="/my/tex/tweak"/</gi> + in your document, this will force a page break if you have at + suitable points, <code>\NAMESPACE{/my/tex/tweak}{tweak.xmt}</code> + and +<eg> +\DeclareNamespace{tweak}{"/my/tex/tweak"} +\XMLelement{tweak:clearpage}{\clearpage} +</eg> +</item> +<item><p> A second different mechanism is available, to use XML processing + instructions. A Processing Instruction of the form: +<gi>?xmltex</gi> <emph>name</emph> {<emph>arg1</emph>} {<emph>arg1</emph>} &ldots; <code>?></code> +will be executed as the &TeX; command: +\<emph>name</emph> {<emph>arg1</emph>} {<emph>arg1</emph>} &ldots;</p> +<p>Note that <emph>only</emph> the first name will be converted into a &TeX; +command, any arguments should only contain character strings. +</p> +</item> +</list> + +</p> +</div> + +<div> +<head>Bugs</head> +<p>None, of course.</p> +</div> + +<div> +<head>Don't Read Past This Point</head> +<p>Thus section discusses some of the more experimental features of xmltex +that may get a cleaner syntax (or be removed, as a bad idea) in later releases, +and also describes some of the internal interfaces (which are also +subject to change)</p> + +<div> +<head>Input Encodings and States</head> +<p>At any point while processing a document, xmltex is in one of two +<emph>states</emph>: <emph>tex</emph> or <emph>xml</emph>.</p> +<div><head>States</head> +<p>In the xml <emph>state</emph>, + < and & are the only two characters that +trigger special markup codes. Other characters, such as !, >, =, +&ldots; may be used in certain XML constructs as markup but unless +some code has been triggered by < they are treated simply as +character data. All characters above 127 are `active' to &TeX; +and are used to translate the input encoding to UTF-8. All internal +character handling is based on UTF-8, as described below. Some +characters in the ASCII range, below 127 are also active by default +(mainly punctuation characters used in XML constructs, such as +the ones listed above). Some or all of the others may be activated +using the <code>\ActivateASCII</code> command, which allows special +typesetting rules to be activated for the characters, at some cost in +processing speed.</p> +<p>In the tex <emph>state</emph>, +characters in the ASCII range have their usual +&TeX; meanings, so letters are `catcode 11' and may be used in &TeX; +control sequences, \ is the escape character, & the table cell +separator, etc. Characters above 127 have the meanings current for the +current encoding just as for the xml state, probably this means that +they are unusable in &TeX; code, except for the special case of +referring to XML element names in the first argument to +<code>\XMLelement</code> and releated commands.</p> +</div> +<div><head>Encodings</head> +<p>Whenever a new (XML or &TeX;) file is input by the xmltex system the +<emph>encoding</emph> is first switched to UTF-8. At the end of the +input the encoding is returned to whatever was the current encoding. +The encoding current while the file is read is determined by the +encoding pseudo-attribute on the XML or text declaration in the case +of XML files, or by the <code>\FileEncoding</code> command for &TeX; +files. Note that the encoding mechanism <emph>only</emph> is triggered +by xmltex file includes. Once an xmltex package file is loaded it may +include other &TeX; files by <code>\input</code> or +<code>\includepackage</code> these input command swill be transparent +to the xmltex encoding system. The vast majority of &TeX; macro +packages only use ASCII characters so this should not be a +problem.</p> +<p>Note that if the <code>\includepackage</code> occurs directly in +the xmltex package file, the &TeX; code will be included with a known +encoding, the one specified in the xmltex package, or UTF-8. If +however the <code>\includepackage</code> is included in code specified +by <code>\XMLelement</code>, then it will be executed with whatever +encoding is current in the document at the point that element is +reached. Before xmltex executes the code for that element it will +switch to the tex state, thus normalising the ascii characters +but characters above 127 will not have predefined definitions in this +case.</p> +<p>Internally eveything is stored as UTF-8. So `aux' and `toc' files +will be in UTF-8 even if the document (or parts of the document) used +different encodings.</p> +<p>To specify a new encoding, if it is an 8 bit encoding that matches +ASCII in the printable ASCII range, then one just needs to produce a +file with name <emph>encoding</emph><code>.xmt</code> (in lowercase, +on case sensitive systems) this should consist of a series of +<code>\InputCharacter</code> commands, giving the input character slot +and the equivalent Unicode. If an encoding is specified in this manner +character data will be converted to UTF-8 by <emph>expansion</emph> +and so ligatures and inter letter kerns will be preserved. (Conversely +if characers are accessed by character references, &#1234; then +&TeX; arithmetic is used to decode the information and ligature +information will be lost. For some large character sets, especially +for Asian languages, these mechanisms will probably not prove to be +sufficient, some mechanisms are being investigated, but in the short +term it may be necessary to always use UTF-8 if the input encoding +is not strictly a ine byte extension of the ASCII code page. +</p></div> + +</div> + +<div> +<head>xmltex Package Commands</head> +<p>You can use arbitrary &TeX; commands in an xmltex package, +althought you should be aware that the file may be input into a local +group, at the point in a document that a particular namespace is first +used, for example. There are however some specific commands designed +to be used in the begin or end code of <code>\XMLElement</code>. +<list type="unordered"> + +<item><p><code>\ignorespaces</code></p> +<p>This is actually a &TeX; primitive +(for the moment!)</p> +</item> + +<item><p><code>\obeyspaces</code></p> +<p>Obey consecutive space characters, +rather than treating consecutive runs as a single space. +(A command of this name, but not this definition is in plain &TeX;.)</p> +</item> + +<item><p><code>\obeylines</code></p> +<p>Obey end of line characters, +rather than treating then as a space, force a line break. +(A command of this name, but not this definition is in plain &TeX;.)</p> +</item> + +<item><p><code>\xmltexfirstchild#1\@</code></p> +<p>If the <emph>start-code</emph> for an element is specified as +<code>\xmlgrab</code> then the <emph>end-code</emph> may use +<code>#1</code> in order to execute the element content. Sometimes you +do not want all of the content. The a construction (with currently +unpleasant syntax) <code>\xmltexfirstchild#1\@</code> will just evaluate +the first child element of the content, discarding the remaining +elements.</p> +</item> + +<item><p><code>\xmltextwochildren\csa\csb#1</code></p> +<p>If you know that the content will be exactly two child elements (for +examle a MathML frac or sub element) then this command may be used. +It will execute the &TeX; code +<code>\csa{</code><emph>child-1</emph><code>}\csb{</code><emph>child-2</emph> +So either two &TeX; command smay be supplied, one will be applied to +each child, or the second argument may be <code>{}</code> in which case +the first argument may be a &TeX; command that takes two arguments. +For example the code for MathMl frac might be +<eg> +\XMLelement{m:mfrac} + {} + {\xmlgrab} + {\xmltextwochildren\frac{}#1} +</eg> +</p> +</item> + +<item><p><code>\xmltexthreechildren\csa\csb\csc#1</code></p> +<p>As above, but more so.</p> +</item> + +<item><p><code>\NDATAEntity\csa\csb\attvalue</code></p> +<p>If the XML parser encounters an internalor external entity reference +it expands it without executing any special hook that may be defined in +an xmltex package. However NDATA entites are never directly encountered +in an entity reference. They may only be used as an attribute value. +If <code>\attvalue</code>. is a &TeX; command holding the value of an +attribute, as declared in <code>\XMLattribute</code> then +<code>\NDATAEntity\csa\csb\attvalue</code> applies the two &TeX; +commands <code>\csa</code> and <code>\csb</code> to the notation type +and the value, in a way exactly corresponding to +<code>\xmltextwochildren</code> so for example the XML document for this +manual specifies +<eg><![CDATA[ + <!NOTATION URL SYSTEM "" > + <!ENTITY lppl SYSTEM "http://www.latex-project.org/lppl.txt" NDATA URL>]]> +</eg> +and this is handled by the following xmltex code +<eg><![CDATA[ +\XMLelement{xptr} + {\XMLattribute{doc}{\xptrdoc}{}} + {\NDATAEntity\xptrdoc\@gobble\url} + {}]]> +</eg> +which saves the attribute value in <code>\xptrdoc</code> and then +discards the notation name (URL) and applies the command +<code>\url</code> to typeset the supplied URL. +</p> +</item> + +</list> +</p> + +</div> + +<div> +<head>Character Data Internals</head> +<p> +<table> +<row> +<cell/> <cell>int.</cell><cell>ext. xml</cell> +<cell>ext. mixed</cell><cell>csn typeout</cell> +<cell/> +</row> +<row> +<cell>d</cell><cell>xabc</cell><cell>xabc</cell> +<cell>xabc (12)</cell><cell>xabc (12)</cell><cell>xabc (12)</cell> +<cell/> +</row> +<row> +<cell>c</cell><cell>xab</cell><cell>xab</cell> +<cell>xab (12)</cell><cell>xab (12)</cell><cell>xab (12)</cell> +<cell/> +</row> +<row> +<cell>b</cell><cell>xa</cell><cell>xa</cell> +<cell>xa (12)</cell><cell>xa (12)</cell><cell>xa (12)</cell> +<cell/> +</row> +<row> +<cell>ax</cell><cell>x</cell><cell>x</cell> +<cell>x</cell><cell>x</cell><cell>x (12)</cell> +<cell>(!)</cell> +</row> +<row> +<cell>ay</cell><cell>x</cell><cell>x</cell> +<cell>x</cell><cell>&#123;</cell><cell>x (12)</cell> +<cell>(e)</cell> +</row> +<row> +<cell>az</cell><cell>x</cell><cell>\az x</cell> +<cell>&#123;</cell><cell>&#123;</cell><cell>x (12)</cell> +<cell>(&lt;)</cell> +</row> +<row> +<cell><</cell><cell><</cell><cell><</cell> +<cell><</cell><cell><</cell><cell>< (12)</cell> +<cell>(<)</cell> +</row> +</table> + +</p> +</div> + + +</div> + + +</body> +</text> +</TEI.2> + + |