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   <title>DocBook V5.0</title><meta name="generator" content="DocBook XSL Stylesheets V1.74.0-pre"><link rel="stylesheet" type="text/css" href="http://docbook.org/docs/howto/howto.css"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="article" lang="en"><div class="titlepage"><h1>DocBook V5.0</h1><h2>The Transition Guide</h2><h3>06&nbsp;February&nbsp;2008</h3><div class="metadata"><h4>This version:</h4><dl class="urilist"><dt><span>http://docbook.org/docs/howto/2008-02-06/</span> (<a href="http://docbook.org/docs/howto/2008-02-06/">HTML</a>, <a href="http://docbook.org/docs/howto/2008-02-06/howto.xml">XML</a>, <a href="http://docbook.org/docs/howto/2008-02-06/howto.pdf">PDF</a>)</dt></dl><h4>Latest version:</h4><dl class="urilist"><dt><span>http://docbook.org/docs/howto/</span> (<a href="http://docbook.org/docs/howto/">HTML</a>, <a href="http://docbook.org/docs/howto/howto.xml">XML</a>, <a href="http://docbook.org/docs/howto/howto.pdf">PDF</a>)</dt></dl><h4>Previous versions:</h4><dl class="urilist"><dt><span>http://docbook.org/docs/howto/2007-10-28/</span> (<a href="http://docbook.org/docs/howto/2007-10-28/">HTML</a>, <a href="http://docbook.org/docs/howto/2007-10-28/howto.xml">XML</a>, <a href="http://docbook.org/docs/howto/2007-10-28/howto.pdf">PDF</a>)</dt><dt><span>http://docbook.org/docs/howto/2006-10-22/</span> (<a href="http://docbook.org/docs/howto/2006-10-22/">HTML</a>, <a href="http://docbook.org/docs/howto/2006-10-22/howto.xml">XML</a>, <a href="http://docbook.org/docs/howto/2006-10-22/howto.pdf">PDF</a>)</dt><dt><span>http://docbook.org/docs/howto/2006-05-16/</span> (<a href="http://docbook.org/docs/howto/2006-05-16/">HTML</a>, <a href="http://docbook.org/docs/howto/2006-05-16/howto.xml">XML</a>, <a href="http://docbook.org/docs/howto/2006-05-16/howto.pdf">PDF</a>)</dt></dl><h4>Authors and other credited contributors:</h4><dl class="authorlist"><dt><span class="personname">Jirka Kosek</span>, <code class="email">&lt;<a class="email" href="mailto:jirka@kosek.cz">jirka@kosek.cz</a>&gt;</code></dt><dt><span class="personname">Norman Walsh</span>, <code class="email">&lt;<a class="email" href="mailto:ndw@nwalsh.com">ndw@nwalsh.com</a>&gt;</code></dt><dt><span class="personname">Dick Hamilton</span>, <code class="email">&lt;<a class="email" href="mailto:rlhamilton@frii.com">rlhamilton@frii.com</a>&gt;</code></dt><dt><span class="personname">Michael(tm) Smith</span>, <code class="email">&lt;<a class="email" href="mailto:smith@sideshowbarker.net">smith@sideshowbarker.net</a>&gt;</code> (contributor)</dt></dl></div><hr></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#introduction">Introduction</a></span></dt><dd><dl><dt><span class="section"><a href="#introduction-ns">Finally in a namespace</a></span></dt><dt><span class="section"><a href="#introduction-rng">Relaxing with DocBook</a></span></dt><dt><span class="section"><a href="#introduction-why-to-switch">Why switch to DocBook V5.0?</a></span></dt><dt><span class="section"><a href="#introduction-schemas">Schema jungle</a></span></dt></dl></dd><dt><span class="section"><a href="#tools">Tool chain</a></span></dt><dd><dl><dt><span class="section"><a href="#editors">Editing DocBook V5.0</a></span></dt><dt><span class="section"><a href="#validators">Validating DocBook V5.0</a></span></dt><dt><span class="section"><a href="#processing">Processing DocBook V5.0</a></span></dt></dl></dd><dt><span class="section"><a href="#changes">Markup changes</a></span></dt><dd><dl><dt><span class="section"><a href="#changes-linking">Improved cross-referencing and linking</a></span></dt><dt><span class="section"><a href="#changes-renamed">Renamed elements</a></span></dt><dt><span class="section"><a href="#changes-removed">Removed elements</a></span></dt></dl></dd><dt><span class="section"><a href="#convert4to5">Converting DocBook V4.x documents to DocBook V5.0</a></span></dt><dd><dl><dt><span class="section"><a href="#entities">What About Entities?</a></span></dt></dl></dd><dt><span class="section"><a href="#customizations">Customizing DocBook V5.0</a></span></dt><dd><dl><dt><span class="section"><a href="#relaxngorg">DocBook RELAX NG schema organization</a></span></dt><dt><span class="section"><a href="#customconsiderations">General customization considerations</a></span></dt><dt><span class="section"><a href="#cust-elements">Elements</a></span></dt><dt><span class="section"><a href="#cust-attributes">Attributes</a></span></dt><dt><span class="section"><a href="#cust-naming">Naming and versioning DocBook customizations</a></span></dt></dl></dd><dt><span class="section"><a href="#faq">FAQ</a></span></dt><dt><span class="bibliography"><a href="#references">Bibliography</a></span></dt></dl></div>


<p>This document is targeted at DocBook users who are considering
switching from DocBook V4.x to DocBook V5.0. It describes
differences between DocBook V4.x and V5.0 and provides some suggestions about
how to edit and process DocBook V5.0 documents. There is
also a section devoted to conversion of legacy documents from DocBook
4.x to DocBook V5.0.</p>

<p>At the time this was written the current version of DocBook V5.0
was 5.0. However, almost all of the information in this document is
general and applies to any newer version of DocBook V5.0.
</p>

<div class="section" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="introduction"></a>Introduction</h2></div></div></div>


<p>The differences between DocBook V4.x and V5.0 are quite radical in
some aspects, but the basic idea behind DocBook is still the same, and
almost all element names are unchanged. Because of this it is very
easy to become familiar with DocBook V5.0 if you know any previous version of
DocBook. You can find a complete list of changes in
[<a class="citation" href="#d5e1018"><span class="citation">DB5SPEC</span></a>], here we will discuss only the most
fundamental changes.</p>

<div class="section" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="introduction-ns"></a>Finally in a namespace</h3></div></div></div>


<p>All DocBook V5.0 elements are in the namespace
<code class="uri">http://docbook.org/ns/docbook</code>. <acronym class="acronym" title="Extensible Markup Language">XML</acronym> namespaces are used to distinguish
between different element sets. In the last few years, almost all new
XML grammars have used their own namespace. It is easy to
create compound documents that contain elements from different XML
vocabularies. DocBook V5.0 is following this design rule. Using
namespaces in your documents is very easy. Consider this
simple article marked up in DocBook V4.5:</p>

<pre class="programlisting">&lt;article&gt;
  &lt;title&gt;Sample article&lt;/title&gt;
  &lt;para&gt;This is a really short article.&lt;/para&gt;
&lt;/article&gt;</pre>

<p>The corresponding DocBook V5.0 article will look very similar:</p>

<pre class="programlisting">&lt;article xmlns="http://docbook.org/ns/docbook" &#8230;&gt;
  &lt;title&gt;Sample article&lt;/title&gt;
  &lt;para&gt;This is a really short article.&lt;/para&gt;
&lt;/article&gt;</pre>

<p>The only change is the addition of a default namespace declaration
(<code class="code">xmlns="http://docbook.org/ns/docbook"</code>) on the root
element. This declaration applies the namespace to the root element and
all nested elements. Each
element is now uniquely identified by its local name and namespace.</p>

<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3>
<p>The namespace name <code class="uri">http://docbook.org/ns/docbook</code> serves
only as an identifier. This resource is not fetched during processing
of DocBook documents, and you are not required to have an Internet
connection during processing. If you access the namespace URI with a browser,
you will find a short explanatory document about the namespace. In the
future this document will probably conform to (some version of) RDDL
and provide pointers to related resources.</p>
</div>

</div>

<div class="section" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="introduction-rng"></a>Relaxing with DocBook</h3></div></div></div>


<p>For more than a decade, the DocBook schema was defined using a
DTD. However, DTDs have serious limitations, and DocBook V5.0 is thus
defined using a very powerful schema language called RELAX NG. Thanks
to RELAX NG, it is now much easier to create customized versions of
DocBook, and some content models are now cleaner and more
precise.</p>

<p>Using RELAX NG has an impact on the document prolog. The following
example shows the typical prolog of a DocBook V4.x document. The version of
the DocBook DTD (in this case 4.5) is indicated in the document type
declaration (!DOCTYPE) which points to a particular version of the
DTD.</p>

<div class="example"><a name="ex.docbook45"></a><p class="title"><b>Example&nbsp;1.&nbsp;DocBook V4.5 document</b></p><div class="example-contents">

<pre class="programlisting">&lt;?xml version="1.0" encoding="utf-8"?&gt;
&lt;!DOCTYPE article PUBLIC '-//OASIS//DTD DocBook XML V4.5//EN'
                         'http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd'&gt;
&lt;article lang="en"&gt;
  &lt;title&gt;Sample article&lt;/title&gt;
  &lt;para&gt;This is a very short article.&lt;/para&gt;
&lt;/article&gt;</pre>
</div></div><br class="example-break">

<p>In contrast, DocBook V5.0 does not depend on DTDs anymore. This
mean that there is no document type declaration and the version of DocBook
used is indicated with the <code class="sgmltag-attribute">version</code>
attribute instead.</p>

<div class="example"><a name="ex.docbook5"></a><p class="title"><b>Example&nbsp;2.&nbsp;DocBook V5.0 document</b></p><div class="example-contents">

<pre class="programlisting">&lt;?xml version="1.0" encoding="utf-8"?&gt;
&lt;article xmlns="http://docbook.org/ns/docbook" version="5.0" xml:lang="en"&gt;
  &lt;title&gt;Sample article&lt;/title&gt;
  &lt;para&gt;This is a very short article.&lt;/para&gt;
&lt;/article&gt;</pre>
</div></div><br class="example-break">

<p>As you can see, DocBook V5.0 is built on top of existing XML
standards as much as possible, for example the <code class="sgmltag-attribute">lang</code> attribute is superseded by the standard
<code class="sgmltag-attribute"><a class="sgmltag" href="http://www.w3.org/TR/REC-xml/#sec-lang-tag" target="_top">xml:lang</a></code> attribute.</p>

<p>Another fundamental change is that there is no direct indication
of the schema used. Later in this document, you will learn how you can
specify a schema to be used for document validation.</p>

<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3>
<p>Although we recommend the RELAX NG schema for DocBook
V5.0, there are also DTD and W3C XML Schema versions available (see <a class="xref" href="#schemas" title="Where to get the schemas">the section called &#8220;Where to get the schemas&#8221;</a>) for tools that do not yet support RELAX NG.</p>
</div>

</div>

<div class="section" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="introduction-why-to-switch"></a>Why switch to DocBook V5.0?</h3></div></div></div>


<p>The simple answer is &#8220;<span class="quote">because DocBook V5.0 is the
future</span>&#8221;. Apart from this marketing blurb, there are also more
technical reasons:</p>

<div class="itemizedlist"><ul type="disc"><li>
<p><span class="emphasis"><em>DocBook V4.x is feature frozen.</em></span>DocBook V4.5
is the last version of DocBook in the V4.x series. Any new DocBook
development, like the addition of new elements, will be done in
DocBook V5.0. It is only matter of time before useful, new elements
will be added into DocBook V5.0, but they are not likely to be back
ported into DocBook V4.x. DocBook V4.x will be in maintenance mode and
errata will be published if necessary. </p>
</li><li>
<p><span class="emphasis"><em>DocBook V5.0 offers new functionality.</em></span>
DocBook V5.0 provides significant improvements over DocBook V4.x. For
example there is general markup for annotations, a new and flexible
system for linking, and unified markup for information sections using
the <a href="http://docbook.org/tdg5/en/html/info.html"><code class="sgmltag-element">info</code></a> element.</p>
</li><li>
<p><span class="emphasis"><em>DocBook V5.0 is more extensible.</em></span> Having
DocBook V5.0 in a separate namespace allows you to easily mix DocBook
markup with other XML-based languages like SVG, MathML, XHTML or even
FooBarML.</p>
</li><li>
<p><span class="emphasis"><em>DocBook V5.0 is easier to customize.</em></span> RELAX
NG offers many powerful constructs that make customization much easier
than it would be using a DTD (see <a class="xref" href="#customizations" title="Customizing DocBook V5.0">the section called &#8220;Customizing DocBook V5.0&#8221;</a>).</p>
</li></ul></div>

</div>

<div class="section" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="introduction-schemas"></a>Schema jungle</h3></div></div></div>


<p>Schemas for DocBook V5.0 are available in several formats at
<a class="link" href="http://www.oasis-open.org/docbook/xml/5.0/" target="_top">http://www.oasis-open.org/docbook/xml/5.0/</a> (or the
mirror at <a class="link" href="http://docbook.org/xml/5.0/" target="_top">http://docbook.org/xml/5.0/</a>).
Only the RELAX NG schema is normative
and it is preferred over the other schema languages.  However, for your
convenience there are also DTD and W3C XML Schema versions provided for DocBook
V5.0. But please note that neither the DTD nor the W3C XML schema are able to
capture all the constraints of DocBook V5.0. This mean that a
document that validates against the DTD or XML schema is not necessarily
valid against the RELAX NG schema and thus may not be a valid
DocBook V5.0 document.</p>

<p>DTD and W3C XML Schema versions of the DocBook V5.0 grammar are provided
as a convenience for users who want to use DocBook V5.0 with legacy tools
that don't support RELAX NG. Authors are encouraged to switch to RELAX
NG based tools as soon as possible, or at least to validate documents
against the RELAX NG schema before further processing.</p>

<p>Some document constraints can't be expressed in schema languages
like RELAX NG or W3C XML Schema. To check for these additional
constraints DocBook&nbsp;V5.0 uses Schematron.  We recommend that you
validate your document against both the RELAX NG and
Schematron schemas.</p>

<div class="section" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="schemas"></a>Where to get the schemas</h4></div></div></div>


<p>The latest versions of schemas can be obtained from <a class="link" href="http://docbook.org/schemas/5x.html" target="_top">http://docbook.org/schemas/5x.html</a>. At the time this was
written the latest version was 5.0. Individual schemas are
available at the following locations:</p>

<div class="variablelist"><dl><dt><span class="term">RELAX NG schema</span></dt><dd><p><a class="link" href="http://docbook.org/xml/5.0/rng/docbook.rng" target="_top">http://docbook.org/xml/5.0/rng/docbook.rng</a></p></dd><dt><span class="term">RELAX NG schema in compact syntax</span></dt><dd><p><a class="link" href="http://docbook.org/xml/5.0/rng/docbook.rnc" target="_top">http://docbook.org/xml/5.0/rng/docbook.rnc</a></p></dd><dt><span class="term">DTD</span></dt><dd><p><a class="link" href="http://docbook.org/xml/5.0/dtd/docbook.dtd" target="_top">http://docbook.org/xml/5.0/dtd/docbook.dtd</a></p></dd><dt><span class="term">W3C XML Schema</span></dt><dd><p><a class="link" href="http://docbook.org/xml/5.0/xsd/docbook.xsd" target="_top">http://docbook.org/xml/5.0/xsd/docbook.xsd</a></p></dd><dt><span class="term">Schematron schema with additional checks</span></dt><dd><p><a class="link" href="http://docbook.org/xml/5.0/sch/docbook.sch" target="_top">http://docbook.org/xml/5.0/sch/docbook.sch</a></p></dd></dl></div>

<p>These schemas are also available from the mirror at
<a class="link" href="http://www.oasis-open.org/docbook/xml/5.0/" target="_top">http://www.oasis-open.org/docbook/xml/5.0/</a>.</p>

</div>

<div class="section" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="docs"></a>DocBook documentation</h4></div></div></div>


<p>Detailed documentation about each DocBook V5.0 element is
presented in <a class="link" href="http://docbook.org/tdg5/en/html/pt02.html" target="_top">the reference part
of <em class="citetitle">DocBook: The Definitive Guide</em></a>.</p>

<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3>
<p>Other parts of <em class="citetitle">DocBook: The Definitive
Guide</em> have not yet been updated to reflect the changes
made in DocBook V5.0. Please do not be confused by this.</p>
</div>

</div>

</div>

</div>

<div class="section" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="tools"></a>Tool chain</h2></div></div></div>


<p>This section briefly describes tools and procedures to edit and
process content stored in DocBook V5.0.</p>

<div class="section" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="editors"></a>Editing DocBook V5.0</h3></div></div></div>


<p>Because DocBook is an XML-based format and XML is a text-based
format, you can use any text editor to create and edit DocBook V5.0
documents. However, using &#8220;<span class="quote">dumb</span>&#8221; editors like Notepad is
not very productive. You will do better if you use an editor that
supports XML. Although there are DTD and W3C XML Schemas available for
DocBook V5.0, which means you can use any editor that works with DTDs
or W3C XML Schemas, we recommend that you use the RELAX NG grammar
with DocBook V5.0. The rest of this section contains an overview of
XML editors (listed in alphabetical order) that are known to work with
RELAX NG schemas and that offer guided editing based on the RELAX NG
schema.</p>

<div class="section" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="editors-nxml"></a>Emacs and nXML</h4></div></div></div>


<p><a class="link" href="http://www.thaiopensource.com/nxml-mode/" target="_top">nXML
mode</a> is an add-on for the <span class="application"><a class="application" href="http://www.gnu.org/software/emacs/emacs.html" target="_top">GNU
Emacs</a></span> text editor. By installing nXML you can turn Emacs
into a very powerful XML editor that offers guided editing and
validation of XML documents.</p>

<div class="figure"><a name="f.emacs"></a><p class="title"><b>Figure&nbsp;1.&nbsp;Emacs with nXML mode provides guided editing and validation</b></p><div class="figure-contents">

<div class="mediaobject"><img src="images/emacs.png" alt="Emacs with nXML mode provides guided editing and validation"></div>
</div></div><br class="figure-break">

<p>nXML uses a special configuration file named
<code class="filename">schemas.xml</code> to associate schemas with XML
documents. Often you will find this file in the directory
<code class="filename">site-lisp/nxml/schema</code> inside the Emacs installation
directory. Adding the following line into the configuration file,
will associate DocBook V5.0 elements with the appropriate
schema:</p>

<pre class="programlisting">&lt;namespace ns="http://docbook.org/ns/docbook" uri="<em class="replaceable"><code>/path/to/</code></em>docbook.rnc"/&gt;</pre>

<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3>
<p>Please note that nXML ships with a file named
<code class="filename">docbook.rnc</code>. This file contains the RELAX NG grammar
for DocBook V4.x. Be sure that you associate the DocBook V5.0 namespace
with the corresponding DocBook V5.0 grammar.</p>
</div>

<p>If you can't edit the global <code class="filename">schemas.xml</code> file,
you can create this file in the same directory as your document. nXML will
find associations placed there also. In this case you must create a
complete configuration file like:</p>

<pre class="programlisting">&lt;locatingRules xmlns="http://thaiopensource.com/ns/locating-rules/1.0"&gt;
  &lt;namespace ns="http://docbook.org/ns/docbook" uri="<em class="replaceable"><code>/path/to/</code></em>docbook.rnc"/&gt;
&lt;/locatingRules&gt;</pre>

</div>

<div class="section" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="editors-oxygen"></a>oXygen</h4></div></div></div>


<p><span class="application"><a class="application" href="http://www.oxygenxml.com/" target="_top">oXygen</a></span> is a feature
rich XML editor. It has built-in support for many schema languages
including RELAX NG. If you want to smoothly edit and validate DocBook
5.0 documents you should associate the DocBook namespace with the
corresponding schema. Go to
<span class="guimenu">Options</span> &#8594; <span class="guisubmenu">Preferences&#8230;</span> &#8594; <span class="guisubmenu">Editor</span> &#8594; <span class="guimenuitem">Default
Schema Associations</span>. Then click the
<span class="guibutton">New</span> button to add a new association. Type in
the DocBook namespace and the RELAX NG schema location, choose the
<span class="guilabel">RNG Schema + Schematron</span> type of schema as, and
confirm your choice by clicking the <span class="guibutton">OK</span>
button.</p>

<div class="figure"><a name="f.oxygen"></a><p class="title"><b>Figure&nbsp;2.&nbsp;Adding a new schema association in oXygen</b></p><div class="figure-contents">

<div class="mediaobject"><img src="images/oxygen1.png" alt="Adding a new schema association in oXygen"></div>
</div></div><br class="figure-break">

<p>Because oXygen comes with preconfigured associations for
DocBook V4.x, you must move your newly added configuration to the
top of the list (using the <span class="guibutton">Up</span> button).
That way you will be able to use
oXygen with both DocBook V4.x and DocBook V5.0.</p>

<div class="figure"><a name="f.oxygen.assoc"></a><p class="title"><b>Figure&nbsp;3.&nbsp;DocBook V5.0 association must precede associations for DocBook V4.x</b></p><div class="figure-contents">

<div class="mediaobject"><img src="images/oxygen2.png" alt="DocBook V5.0 association must precede associations for DocBook V4.x"></div>
</div></div><br class="figure-break">

<p>Now you can close the preference box by clicking on the
<span class="guibutton">OK</span> button. oXygen will assist
you with writing DocBook V5.0 content, and you will be able to validate
your documents against both RELAX NG and Schematron schemas. </p>

<div class="figure"><a name="f.oxygen.open5"></a><p class="title"><b>Figure&nbsp;4.&nbsp;DocBook V5.0 document opened in oXygen</b></p><div class="figure-contents">

<div class="mediaobject"><table border="0" summary="manufactured viewport for HTML img" cellspacing="0" cellpadding="0" width="100%"><tr><td><img src="images/oxygen3.png" width="100%" alt="DocBook V5.0 document opened in oXygen"></td></tr></table></div>
</div></div><br class="figure-break">

</div>

<div class="section" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="editors-xxe"></a>XML Mind XML editor</h4></div></div></div>


<p><span class="application"><a class="application" href="http://www.xmlmind.com/xmleditor/" target="_top">XML
Mind XML editor</a></span> (XXE) is a visual validating XML editor that
provides a wordprocessor-like interface to users. It is available in
two versions, Standard and Professional. The Standard version is free and
provides everything you need to edit DocBook V5.0 documents.</p>

<div class="figure"><a name="f.xmlmind"></a><p class="title"><b>Figure&nbsp;5.&nbsp;XML Mind XML Editor &#8211; feels almost like MS Word but real DocBook V5.0 markup is created</b></p><div class="figure-contents">

<div class="mediaobject"><table border="0" summary="manufactured viewport for HTML img" cellspacing="0" cellpadding="0" width="100%"><tr><td><img src="images/xxe.png" width="100%" alt="XML Mind XML Editor &#8211; feels almost like MS Word but real DocBook V5.0 markup is created"></td></tr></table></div>
</div></div><br class="figure-break">

<p>In order to use DocBook V5.0 in XXE you have to install
an add-on. Go to
<span class="guimenu">Options</span> &#8594; <span class="guimenuitem">Install
Add-ons&#8230;</span>. Then choose <span class="guilabel">DocBook
5 configuration</span> and press the <span class="guibutton">OK</span>
button. After restart, XXE is ready to work with DocBook V5.0
documents.</p>

</div>

</div>

<div class="section" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="validators"></a>Validating DocBook V5.0</h3></div></div></div>


<p>If you are not using a RELAX NG-based validating editor when you
create documents, we strongly recommend that you validate your
documents against RELAX NG and Schematron schemas before processing
them. Only after successful validation can you be sure that your
document is really DocBook V5.0 and that processing tools will be able
to process it correctly.</p>

<p>For validation you can use tools that support simultaneous RELAX NG and
Schematron validation, or you can use NVDL to orchestrate validation using
the two schemas.</p>

<div class="section" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="validators-rng-sch"></a>Using RELAX NG and Schematron</h4></div></div></div>


<p>You can find a list of RELAX NG validators at <a class="link" href="http://relaxng.org/#validators" target="_top">http://relaxng.org/#validators</a>. It is best to use
validators with support for embedded Schematron rules inside RELAX NG
schemas. Schematron is a rule-based validation language which is used
to impose additional constraints on DocBook documents. Schematron rules
assert conditions which are impossible or difficult to express 
in a pure RELAX NG schema.</p>

<p><span class="application"><a class="application" href="https://msv.dev.java.net/" target="_top">Sun 
Multi-Schema XML Validator (MSV)</a></span> is able to validate an XML
document against a RELAX NG schema and Schematron rules at the same time.
To install and use MSV follow these steps:</p>

<div class="procedure"><ol type="1"><li>
<p>Download <code class="filename">relames.zip</code> from <a class="link" href="https://msv.dev.java.net/servlets/ProjectDocumentList?folderID=101" target="_top">https://msv.dev.java.net/servlets/ProjectDocumentList?folderID=101</a>.</p>
</li><li>
<p>Unpack the downloaded file into an arbitrary directory.</p>
</li><li>
<p>Validate your document using the following command:</p>
<pre class="screen"><span class="command"><strong>java</strong></span> -Xss512K -jar <em class="replaceable"><code>/path/to/</code></em>relames.jar <em class="replaceable"><code>/path/to/</code></em>docbook.rng document.xml</pre>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3>
<p>The switch <code class="option">-Xss512K</code> increases the stack size
of the Java virtual machine. This is necessary because the DocBook schema is
quite large. If you get stack overflow errors from MSV, increase
this value. You may get spurious error messages if the value
is too small, so if you get a stack overflow error, ignore any other error
messages and try a larger value for the stack size.
If you are not using Sun's Java implementation, please consult the
documentation for your virtual machine to learn how to increase the stack
size.</p>
</div>
</li></ol></div>

<p>There is also an <a class="link" href="http://relaxed.vse.cz/docbookvalidator/" target="_top">on-line DocBook&nbsp;V5.0
validator</a> that validates DocBook V5.0 documents against the normative
RELAX NG schema with embedded Schematron rules.</p>

</div>

<div class="section" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="d5e238"></a>Using NVDL</h4></div></div></div>


<p>NVDL is a meta-schema language which can validate a document 
against several schemas. DocBook&nbsp;V5.0 comes with a NVDL
schema which specifies that DocBook documents should be validated
against both RELAX NG and Schematron schemas.</p>

<p>You can find a list of NVDL validators at <a class="link" href="http://nvdl.org/" target="_top">http://nvdl.org/</a>. The following procedures show how to
install and use the <span class="application"><a class="application" href="http://www.oxygenxml.com/onvdl.html" target="_top">oNVDL</a></span> and
<span class="application"><a class="application" href="http://jnvdl.sourceforge.net" target="_top">JNVDL</a></span>
validators.</p>

<div class="procedure"><a name="d5e245"></a><p class="title"><b>Procedure&nbsp;1.&nbsp;oNVDL installation and usage</b></p><ol type="1"><li>
<p>Download <code class="filename"><a class="filename" href="http://www.oxygenxml.com/InstData/onvdl/onvdl-20070517.zip" target="_top">onvdl-20070517.zip</a></code>.</p>
</li><li>
<p>Unpack the downloaded file into an arbitrary directory.</p>
</li><li>
<p>Validate your document using the following command:</p>
<pre class="screen"><span class="command"><strong>java</strong></span> -jar <em class="replaceable"><code>/path/to/oNVDL/</code></em>bin/onvdl.jar <em class="replaceable"><code>/path/to/</code></em>docbook.nvdl document.xml</pre>
</li></ol></div>

<div class="procedure"><a name="d5e258"></a><p class="title"><b>Procedure&nbsp;2.&nbsp;JNVDL installation and usage</b></p><ol type="1"><li>
<p>Download the latest release of JNVDL from <a class="link" href="http://sourceforge.net/project/showfiles.php?group_id=164464" target="_top">http://sourceforge.net/project/showfiles.php?group_id=164464</a>.</p>
</li><li>
<p>Unpack the downloaded file into an arbitrary directory.</p>
</li><li>
<p>Modify file <code class="filename">jnvdl.bat</code> (or <code class="filename">jnvdl.sh</code> on Unix based systems) to include <code class="option">-Xss512K</code> switch directly after <span class="command"><strong>java</strong></span> command.</p>
</li><li>
<p>On Windows systems, validate your document using the following command:</p>
<pre class="screen"><em class="replaceable"><code>/path/to/jnvdl/</code></em><span class="command"><strong>jnvdl</strong></span> -nt -s <em class="replaceable"><code>/path/to/</code></em>docbook.nvdl document.xml</pre>
<p>On Unix systems, validate your document using the following command:</p>
<pre class="screen"><em class="replaceable"><code>/path/to/jnvdl/</code></em><span class="command"><strong>jnvdl.sh</strong></span> -nt -s <em class="replaceable"><code>/path/to/</code></em>docbook.nvdl document.xml</pre>
</li></ol></div>

</div>

</div>

<div class="section" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="processing"></a>Processing DocBook V5.0</h3></div></div></div>


<p>Part of DocBook's great success can be attributed to the
availability of free
tools that can be used to transform DocBook content into various
target formats including HTML and PDF. The DocBook XSL Stylesheets are
very popular tools.</p>

<div class="section" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="dbxsl"></a>DocBook XSL Stylesheets</h4></div></div></div>


<p>The DocBook stylesheets are designed to process content written in
different versions of DocBook (for example 3.1 and 4.2). Recent
versions of the stylesheets are also able to process DocBook V5.0
with some limitations.</p>

<p>You can process DocBook V5.0 documents with the DocBook XSL
stylesheets in exactly the same way you process DocBook V4.x documents.
You do not need special software; you can stick to your preferred
XSLT processor, be it Saxon, xsltproc, Xalan or whatever else (but see
the note about the lost base URI below).</p>

<p>During document processing, the stylesheets strip
namespaces from DocBook V5.0 to get a document which will be
very similar to DocBook V4.x. This is necessary because from the XSLT
point of view, elements from different namespaces are distinct and cannot 
be easily processed by the same set of templates. This process is
completely transparent to the user. If you are processing DocBook V5.0
documents, the only difference is that you will see the following
additional message:</p>

<pre class="screen">Note: namesp. cut : stripped namespace before processing
Note: namesp. cut : processing stripped document</pre>

<p>Although you can successfully use the existing stylesheets to
process DocBook V5.0, there are some limitations and unsupported
features. The unsupported features include:</p>

<div class="itemizedlist"><ul type="disc"><li><p>general annotations;</p></li><li><p>general XLink links on all elements.</p></li></ul></div>

<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3>
<p>During namespace stripping, the base URI of the document is
lost. This means that in rare situations, relatively referenced
resources like images or programlistings can be processed incorrectly.
The stylesheets attempt to compensate for this problem, but that is not always 
possible. When an XSLT processor other than Saxon or Xalan is used, a warning 
message is generated:

</p><pre class="screen">WARNING: cannot add @xml:base to node set root element. Relative paths may not work.</pre><p>
</p>

</div>
</div>

<div class="section" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="dbxsl-ns"></a>DocBook XSL-NS Stylesheets</h4></div></div></div>

<p>As you can see from reading the previous section, namespace
  stripping has limitations that will cause trouble in some
  situations. To overcome those limitations, Bob Stayton created a
  build system for taking the non-namespace-aware DocBook XSL
  stylesheets and generating namespace-aware versions from them.
  The DocBook <a class="link" href="http://docbook.sourceforge.net/release/xsl-ns/current/" target="_top">XSL-NS stylesheets</a> are the result.</p>

<p>The DocBook XSL-NS stylesheets are released side-by-side
  with the DocBook XSL stylesheets, as a separate <a class="link" href="https://sourceforge.net/project/showfiles.php?group_id=21935&amp;package_id=219178" target="_top"><span class="package">docbook-xsl-ns</span></a> package. They are the
recommended XSLT 1.0 stylesheets to use for transforming
namespaced (DocBook V5.0) documents.</p>
</div>

<div class="section" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="dbxsl2"></a>XSLT 2.0 based re-implementation</h4></div></div></div>


<p>XSLT 1.0 is missing some important features. To work around
these missing features, the current DocBook XSL stylesheets use some
implementation-specific extensions.
XSLT 2.0 adds many new and previously missing features into the language.
A new set of DocBook stylesheets is being implemented based on XSLT 2.0
to take advantage of these features and to fully support DocBook V5.0.
</p>

<p>The XSLT 2.0 based stylesheets have many new features, including:</p>

<div class="itemizedlist"><ul type="disc"><li><p>seamless integration of profiling (conditional
documents) with external bibliographies and
glossaries;</p></li><li><p>no need for (most) external extensions;</p></li><li><p>internationalized indexes;</p></li><li><p>easy to customize titlepage templates.</p></li></ul></div>

<p>The XSLT 2.0 based stylesheets are still under development.  At
this writing, they only support HTML and chunked HTML output.  As time
permits, the stylesheet developers will be adding other formats.  Since
the stylesheets are developed in the limited free time the developers
have, there's no specific schedule.</p>

<p>There are not very many XSLT 2.0 implementations available.
But, if you want to try the new stylesheets, grab a snapshot of
the development version from <a class="link" href="http://docbook.sourceforge.net/snapshots/docbook-xsl2-snapshot.tar.bz2" target="_top">http://docbook.sourceforge.net/snapshots/docbook-xsl2-snapshot.tar.bz2</a>
and unpack it somewhere. Then download and install Saxon&nbsp;9 from <a class="link" href="http://saxon.sf.net" target="_top">http://saxon.sf.net</a>.</p>

<p>To transform a DocBook V5.0 document to a single HTML page use the command:</p>

<pre class="screen"><span class="command"><strong>java</strong></span> -jar <em class="replaceable"><code>/path/to/</code></em>saxon9.jar -o output.html document.xml <em class="replaceable"><code>/path/to/</code></em>docbook-xsl2-snapshot/html/docbook.xsl</pre>

<p>To transform a DocBook V5.0 document to a set of chunked HTML pages use the command:</p>

<pre class="screen"><span class="command"><strong>java</strong></span> -jar <em class="replaceable"><code>/path/to/</code></em>saxon9.jar document.xml <em class="replaceable"><code>/path/to/</code></em>docbook-xsl2-snapshot/html/chunk.xsl</pre>

</div>

</div>

</div>

<div class="section" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="changes"></a>Markup changes</h2></div></div></div>


<p>This section describes the most common markup changes
between DocBook V4.x and V5.0.
You can find a complete list of changes in
[<a class="citation" href="#d5e1018"><span class="citation">DB5SPEC</span></a>].</p>

<div class="section" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="changes-linking"></a>Improved cross-referencing and linking</h3></div></div></div>


<p>In DocBook V4.x the attribute <code class="sgmltag-attribute">id</code> is
used to assign a unique identifier to an element. In DocBook V5.0 this
attribute is renamed <code class="sgmltag-attribute">xml:id</code> in order
to comply with [<a class="citation" href="#d5e1013"><span class="citation">XMLID</span></a>].</p>

<p>Now you can use almost any inline element as the source of a link,
not just <a href="http://docbook.org/tdg5/en/html/xref.html"><code class="sgmltag-element">xref</code></a> or <a href="http://docbook.org/tdg5/en/html/link.html"><code class="sgmltag-element">link</code></a>. For example, the following
DocBook 4.x content:</p> 

<pre class="programlisting">&lt;section id="dir"&gt;
  &lt;title&gt;DIR command&lt;/title&gt;
  &lt;para&gt;...&lt;/para&gt;
&lt;/section&gt;

&lt;section id="ls"&gt;
  &lt;title&gt;LS command&lt;/title&gt;
  &lt;para&gt;This command is a synonym for &lt;link linkend="dir"&gt;&lt;command&gt;DIR&lt;/command&gt;&lt;/link&gt; command.&lt;/para&gt;
&lt;/section&gt;</pre>

<p>is written in DocBook V5.0 as:</p>

<pre class="programlisting">&lt;section xml:id="dir"&gt;
  &lt;title&gt;DIR command&lt;/title&gt;
  &lt;para&gt;...&lt;/para&gt;
&lt;/section&gt;

&lt;section xml:id="ls"&gt;
  &lt;title&gt;LS command&lt;/title&gt;
  &lt;para&gt;This command is a synonym for &lt;command linkend="dir"&gt;DIR&lt;/command&gt; command.&lt;/para&gt;
&lt;/section&gt;</pre>

<p>The <code class="sgmltag-attribute">linkend</code> attribute was added to all
inline elements together with the <code class="sgmltag-attribute">href</code>
attribute from the XLink namespace. This means that you can use any inline
element as the source of a hypertext link. To use XLinks you have
to declare the XLink namespace (most often on the root element of your
document):</p>

<pre class="programlisting">&lt;article xmlns="http://docbook.org/ns/docbook" 
         xmlns:xl="http://www.w3.org/1999/xlink" version="5.0"&gt;
  &lt;title&gt;Test article&lt;/title&gt;

  &lt;para&gt;&lt;application xl:href="http://www.gnu.org/software/emacs/emacs.html"&gt;Emacs&lt;/application&gt; 
    is my favourite text editor.&lt;/para&gt;
  &#8230;</pre>

<p>The <a href="http://docbook.org/tdg/en/html/ulink.html"><code class="sgmltag-element">ulink</code></a> element was removed from DocBook V5.0
in favor of XLink linking. Instead of the DocBook V4.x <a href="http://docbook.org/tdg/en/html/ulink.html"><code class="sgmltag-element">ulink</code></a>
element:</p>

<pre class="programlisting">&lt;ulink url="http://docbook.org"&gt;DocBook site&lt;/ulink&gt;</pre>

<p>you can now use <a href="http://docbook.org/tdg5/en/html/link.html"><code class="sgmltag-element">link</code></a></p>

<pre class="programlisting">&lt;link xl:href="http://docbook.org"&gt;DocBook site&lt;/link&gt;</pre>

<p>XLink links may contain a fragment identifier, which you can 
use instead of <code class="sgmltag-attribute">linkend</code> to form
cross-references inside a document; for example:</p>

<pre class="programlisting">&lt;command xl:href="#dir"&gt;DIR&lt;/command&gt;</pre>

<p>However XLink links are not checked during validation, while <code class="sgmltag-attribute">xml:id</code>/<code class="sgmltag-attribute">linkend</code>
links are checked for ID/IDREF consistency.
One place where the XLink-based, fragment identifier scheme is
useful is when XInclude is being used, since XML ID/IDREF links
cannot span XInclude boundaries.
You can use whichever approach better suits your needs.</p>
</div>

<div class="section" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="changes-renamed"></a>Renamed elements</h3></div></div></div>


<p>Some elements were renamed to better express their meaning or to
reduce the total number of elements available in DocBook.</p>

<div class="table"><a name="t.renamed"></a><p class="title"><b>Table&nbsp;1.&nbsp;Renamed elements</b></p><div class="table-contents">

<table summary="Renamed elements" border="1"><colgroup><col width="50%"><col width="50%"></colgroup><thead><tr><th>Old name</th><th>New name</th></tr></thead><tbody><tr><td><a href="http://docbook.org/tdg/en/html/sgmltag.html"><code class="sgmltag-element">sgmltag</code></a></td><td><a href="http://docbook.org/tdg5/en/html/tag.html"><code class="sgmltag-element">tag</code></a></td></tr><tr><td><a href="http://docbook.org/tdg/en/html/bookinfo.html"><code class="sgmltag-element">bookinfo</code></a>, <a href="http://docbook.org/tdg/en/html/articleinfo.html"><code class="sgmltag-element">articleinfo</code></a>,
<a href="http://docbook.org/tdg/en/html/chapterinfo.html"><code class="sgmltag-element">chapterinfo</code></a>, <code class="sgmltag-element">*info</code></td><td><a href="http://docbook.org/tdg5/en/html/info.html"><code class="sgmltag-element">info</code></a></td></tr><tr><td><a href="http://docbook.org/tdg/en/html/authorblurb.html"><code class="sgmltag-element">authorblurb</code></a></td><td><a href="http://docbook.org/tdg5/en/html/personblurb.html"><code class="sgmltag-element">personblurb</code></a></td></tr><tr><td><a href="http://docbook.org/tdg/en/html/collabname.html"><code class="sgmltag-element">collabname</code></a>, <a href="http://docbook.org/tdg/en/html/corpauthor.html"><code class="sgmltag-element">corpauthor</code></a>,
<a href="http://docbook.org/tdg/en/html/corpcredit.html"><code class="sgmltag-element">corpcredit</code></a>, <a href="http://docbook.org/tdg/en/html/corpname.html"><code class="sgmltag-element">corpname</code></a></td><td><a href="http://docbook.org/tdg5/en/html/orgname.html"><code class="sgmltag-element">orgname</code></a></td></tr><tr><td><a href="http://docbook.org/tdg/en/html/isbn.html"><code class="sgmltag-element">isbn</code></a>, <a href="http://docbook.org/tdg/en/html/issn.html"><code class="sgmltag-element">issn</code></a>,
<a href="http://docbook.org/tdg/en/html/pubsnumber.html"><code class="sgmltag-element">pubsnumber</code></a></td><td><a href="http://docbook.org/tdg5/en/html/biblioid.html"><code class="sgmltag-element">biblioid</code></a></td></tr><tr><td><a href="http://docbook.org/tdg/en/html/lot.html"><code class="sgmltag-element">lot</code></a>, <a href="http://docbook.org/tdg/en/html/lotentry.html"><code class="sgmltag-element">lotentry</code></a>, <a href="http://docbook.org/tdg/en/html/tocback.html"><code class="sgmltag-element">tocback</code></a>,
<a href="http://docbook.org/tdg/en/html/tocchap.html"><code class="sgmltag-element">tocchap</code></a>, <a href="http://docbook.org/tdg/en/html/tocfront.html"><code class="sgmltag-element">tocfront</code></a>, <a href="http://docbook.org/tdg/en/html/toclevel1.html"><code class="sgmltag-element">toclevel1</code></a>,
<a href="http://docbook.org/tdg/en/html/toclevel2.html"><code class="sgmltag-element">toclevel2</code></a>, <a href="http://docbook.org/tdg/en/html/toclevel3.html"><code class="sgmltag-element">toclevel3</code></a>, <a href="http://docbook.org/tdg/en/html/toclevel4.html"><code class="sgmltag-element">toclevel4</code></a>,
<a href="http://docbook.org/tdg/en/html/toclevel5.html"><code class="sgmltag-element">toclevel5</code></a>, <a href="http://docbook.org/tdg/en/html/tocpart.html"><code class="sgmltag-element">tocpart</code></a></td><td><a href="http://docbook.org/tdg5/en/html/tocdiv.html"><code class="sgmltag-element">tocdiv</code></a></td></tr><tr><td><a href="http://docbook.org/tdg/en/html/graphic.html"><code class="sgmltag-element">graphic</code></a>, <a href="http://docbook.org/tdg/en/html/graphicco.html"><code class="sgmltag-element">graphicco</code></a>,
<a href="http://docbook.org/tdg/en/html/inlinegraphic.html"><code class="sgmltag-element">inlinegraphic</code></a>, <a href="http://docbook.org/tdg/en/html/mediaobjectco.html"><code class="sgmltag-element">mediaobjectco</code></a></td><td><a href="http://docbook.org/tdg5/en/html/mediaobject.html"><code class="sgmltag-element">mediaobject</code></a> and <a href="http://docbook.org/tdg5/en/html/inlinemediaobject.html"><code class="sgmltag-element">inlinemediaobject</code></a></td></tr><tr><td><a href="http://docbook.org/tdg/en/html/ulink.html"><code class="sgmltag-element">ulink</code></a></td><td><a href="http://docbook.org/tdg5/en/html/link.html"><code class="sgmltag-element">link</code></a></td></tr><tr><td><a href="http://docbook.org/tdg/en/html/ackno.html"><code class="sgmltag-element">ackno</code></a></td><td><a href="http://docbook.org/tdg5/en/html/acknowledgements.html"><code class="sgmltag-element">acknowledgements</code></a></td></tr></tbody></table>
</div></div><br class="table-break">

</div>

<div class="section" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="changes-removed"></a>Removed elements</h3></div></div></div>


<p>The following elements were removed from DocBook V5.0 without
direct replacements: <a href="http://docbook.org/tdg/en/html/action.html"><code class="sgmltag-element">action</code></a>, <a href="http://docbook.org/tdg/en/html/beginpage.html"><code class="sgmltag-element">beginpage</code></a>, <a href="http://docbook.org/tdg/en/html/highlights.html"><code class="sgmltag-element">highlights</code></a>,
<a href="http://docbook.org/tdg/en/html/interface.html"><code class="sgmltag-element">interface</code></a>, <a href="http://docbook.org/tdg/en/html/invpartnumber.html"><code class="sgmltag-element">invpartnumber</code></a>, <a href="http://docbook.org/tdg/en/html/medialabel.html"><code class="sgmltag-element">medialabel</code></a>, <a href="http://docbook.org/tdg/en/html/modespec.html"><code class="sgmltag-element">modespec</code></a>,
<a href="http://docbook.org/tdg/en/html/structfield.html"><code class="sgmltag-element">structfield</code></a>, <a href="http://docbook.org/tdg/en/html/structname.html"><code class="sgmltag-element">structname</code></a>.
If you use one or more of these elements, here are some suggestions
as to how to re-code them in DocBook V5.0.
</p>

<div class="table"><a name="t.removed"></a><p class="title"><b>Table&nbsp;2.&nbsp;Recommended mapping for removed elements</b></p><div class="table-contents">

<table summary="Recommended mapping for removed elements" border="1"><colgroup><col width="50%"><col width="50%"></colgroup><thead><tr><th>Old name</th><th>Recommended mapping</th></tr></thead><tbody><tr><td><a href="http://docbook.org/tdg/en/html/action.html"><code class="sgmltag-element">action</code></a></td><td>Use <code class="computeroutput">&lt;<a href="http://docbook.org/tdg5/en/html/phrase.html"><code class="sgmltag-element">phrase</code></a> remap="action"&gt;</code>.</td></tr><tr><td><a href="http://docbook.org/tdg/en/html/beginpage.html"><code class="sgmltag-element">beginpage</code></a></td><td>Remove: <a href="http://docbook.org/tdg/en/html/beginpage.html"><code class="sgmltag-element">beginpage</code></a> is advisory only
and has tended to cause confusion.  A processing instruction or
comment should be a workable replacement if one is needed.</td></tr><tr><td><a href="http://docbook.org/tdg/en/html/highlights.html"><code class="sgmltag-element">highlights</code></a></td><td>Use <a href="http://docbook.org/tdg5/en/html/abstract.html"><code class="sgmltag-element">abstract</code></a>.  Note that because <a href="http://docbook.org/tdg/en/html/highlights.html"><code class="sgmltag-element">highlights</code></a> has a broader content model, you may
need to wrap contents in a <a href="http://docbook.org/tdg5/en/html/para.html"><code class="sgmltag-element">para</code></a> inside
<a href="http://docbook.org/tdg5/en/html/abstract.html"><code class="sgmltag-element">abstract</code></a>.</td></tr><tr><td><a href="http://docbook.org/tdg/en/html/interface.html"><code class="sgmltag-element">interface</code></a></td><td>Use one of the &#8220;<span class="quote">gui*</span>&#8221; elements
(<a href="http://docbook.org/tdg5/en/html/guibutton.html"><code class="sgmltag-element">guibutton</code></a>, <a href="http://docbook.org/tdg5/en/html/guiicon.html"><code class="sgmltag-element">guiicon</code></a>, <a href="http://docbook.org/tdg5/en/html/guilabel.html"><code class="sgmltag-element">guilabel</code></a>,
<a href="http://docbook.org/tdg5/en/html/guimenu.html"><code class="sgmltag-element">guimenu</code></a>, <a href="http://docbook.org/tdg5/en/html/guimenuitem.html"><code class="sgmltag-element">guimenuitem</code></a>, or
<a href="http://docbook.org/tdg5/en/html/guisubmenu.html"><code class="sgmltag-element">guisubmenu</code></a>).</td></tr><tr><td><a href="http://docbook.org/tdg/en/html/invpartnumber.html"><code class="sgmltag-element">invpartnumber</code></a></td><td>Use <code class="computeroutput">&lt;<a href="http://docbook.org/tdg5/en/html/biblioid.html"><code class="sgmltag-element">biblioid</code></a> class="other"
otherclass="medialabel"&gt;</code>.  The
<a href="http://docbook.org/tdg5/en/html/productnumber.html"><code class="sgmltag-element">productnumber</code></a> element is another alternative.</td></tr><tr><td><a href="http://docbook.org/tdg/en/html/medialabel.html"><code class="sgmltag-element">medialabel</code></a></td><td>Use <code class="computeroutput">&lt;<a href="http://docbook.org/tdg5/en/html/citetitle.html"><code class="sgmltag-element">citetitle</code></a>
pubwork="<em class="replaceable"><code>mediatype</code></em>"&gt;</code>,
where <em class="replaceable"><code>mediatype</code></em> is the type of media being
labeled (e.g.,<code class="sgmltag-attvalue">cdrom</code> or <code class="sgmltag-attvalue">dvd</code>).</td></tr><tr><td><a href="http://docbook.org/tdg/en/html/modespec.html"><code class="sgmltag-element">modespec</code></a></td><td>No longer needed.  The current processing model for
<a href="http://docbook.org/tdg5/en/html/olink.html"><code class="sgmltag-element">olink</code></a> renders <a href="http://docbook.org/tdg/en/html/modespec.html"><code class="sgmltag-element">modespec</code></a>
unnecessary.</td></tr><tr><td><a href="http://docbook.org/tdg/en/html/structfield.html"><code class="sgmltag-element">structfield</code></a>, <a href="http://docbook.org/tdg/en/html/structname.html"><code class="sgmltag-element">structname</code></a></td><td>Use <a href="http://docbook.org/tdg5/en/html/varname.html"><code class="sgmltag-element">varname</code></a>. If you need to distinguish between the
two, use <code class="computeroutput">&lt;<a href="http://docbook.org/tdg5/en/html/varname.html"><code class="sgmltag-element">varname</code></a>
remap="<em class="replaceable"><code>structname or
structfield</code></em>"&gt;</code>.  In some contexts, it
may also be appropriate to use <a href="http://docbook.org/tdg5/en/html/property.html"><code class="sgmltag-element">property</code></a> for <a href="http://docbook.org/tdg/en/html/structfield.html"><code class="sgmltag-element">structfield</code></a>.</td></tr></tbody></table>
</div></div><br class="table-break">

</div>

</div>

<div class="section" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="convert4to5"></a>Converting DocBook V4.x documents to DocBook V5.0</h2></div></div></div>


<p>The DocBook V5.0 schema ships with an XSLT 1.0 stylesheet that
is designed to transform valid DocBook V4.x documents to valid
DocBook V5.0 documents.</p>

<p>To convert your document, <code class="filename">doc.xml</code> in the
examples below, follow these steps:</p>

<div class="procedure"><ol type="1"><li>
<p>Check the validity of your DocBook XML V4.x document. The
conversion tool assumes that the input document is valid. If the input
document contains markup errors, the results will be unpredictable at
best.</p>
</li><li>
<p>Transform <code class="filename">doc.xml</code> to
<code class="filename">newdoc.xml</code> with the
<code class="filename">db4-upgrade.xsl</code> stylesheet included in the
DocBook V5.0 distribution that you are using.</p>
</li><li>
<p>Check the validity of your DocBook XML V5.0 document against
the DocBook V5.0 RELAX NG grammar.</p>
</li></ol></div>

<p>In the vast majority of cases, the resulting document should
be valid and your conversion process is finished.</p>

<p>If the document is not valid, please report the problem.
(Over time, we'll have more experience with the sorts of things
that can go wrong and we'll update this document to reflect that
experience.)</p>

<div class="section" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="entities"></a>What About Entities?</h3></div></div></div>


<p>Using XSLT to transform existing documents to DocBook V5.0 has
one potential disadvantage: it removes all entity references from 
your document.</p>

<p>If preserving entities is an important aspect of your production
work flow, you will have to engage in a semi-manual process to
preserve them.</p>

<div class="procedure"><ol type="1"><li>
<p>Open your existing document using your favorite editing tool.
You must use a tool that <span class="emphasis"><em>is not</em></span> XML-aware, or one
that allows you to edit markup &#8220;in the raw&#8221;.</p>
</li><li>
<p>Replace all occurrences of the entity references that you want
to preserve with some unique string. For example, if you want to preserve
&#8220;<code class="literal">&amp;Product;</code>&#8221; references, you could replace them
all with &#8220;<code class="literal">[[[Product]]]</code>&#8221; (assuming that the string
&#8220;<code class="literal">[[[Product]]]</code>&#8221; doesn't occur anywhere else in your document).</p>
</li><li>
<p>Copy the document type declaration off of your document and save
it some place. The document type declaration is everything from
&#8220;<code class="literal">&lt;!DOCTYPE</code>&#8221; to the closing &#8220;<code class="literal">]&gt;</code>&#8221;.
</p>
</li><li>
<p>Perform the conversion described in <a class="xref" href="#convert4to5" title="Converting DocBook V4.x documents to DocBook V5.0">the section called &#8220;Converting DocBook V4.x documents to DocBook V5.0&#8221;</a>.
</p>
</li><li>
<p>Open the new document using your favorite editing tool. Replace
all occurrences of the unique string you used to save the entity references
with the corresponding entity references.</p>
</li><li>
<p>Paste the document type declaration that you saved onto the top
of your new document.</p>
</li><li>
<p>Remove the external identifier (the <code class="literal">PUBLIC</code>
and/or <code class="literal">SYSTEM</code> keywords) from the document type
declaration. A document that begins:</p>
<pre class="programlisting">&lt;!DOCTYPE book [
&lt;!ENTITY someEntity "some replacement text"&gt;
]&gt;</pre>
<p>is perfectly well-formed. If you don't remove the references to
the DTD, then your parser will likely try to validate against DocBook
V4.0 and that's not going to work. Alternatively, you could refer
to the DocBook V5.0 DTD.</p>
</li></ol></div>

<div class="tip" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Tip</h3>
<p>Steps 2 and 5 from previous procedure can be automated using the
<a class="link" href="http://docbook.svn.sourceforge.net/viewvc/docbook/trunk/contrib/tools/cloak" target="_top">cloak
script</a> written by Michael Smith.</p>
</div>

<div class="section" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="extparsedentities"></a>External Parsed Entities</h4></div></div></div>


<p>External parsed entities, entities which load part of a document
from another file, are a special case. These can often be replaced
with XInclude elements.</p>

<p>The Perl script <code class="filename">db4-entities.pl</code>, also included
in the DocBook V5.0 distribution attempts to perform this replacement
for you. To use the script, perform the following steps:</p>

<div class="procedure"><ol type="1"><li>
<p>Process your document with <code class="filename">db4-entities.pl</code>.
The script expects a single filename and prints the XInclude version
on standard output.</p>
</li><li>
<p>Process the XInclude version as described in <a class="xref" href="#convert4to5" title="Converting DocBook V4.x documents to DocBook V5.0">the section called &#8220;Converting DocBook V4.x documents to DocBook V5.0&#8221;</a>.
</p>
</li></ol></div>
</div>
</div>

</div>

<div class="section" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="customizations"></a>Customizing DocBook V5.0</h2></div></div></div>
  
  

  <p>
    It's much easier to customize DocBook V5.0 than it was to
    customize earlier releases.  This is partly because RELAX NG
    provides better support for modifications than DTDs and partly
    because the DocBook schema is designed to take full advantage
    of the capabilities RELAX NG provides.
    This section describes the organization of the RELAX NG schema for
    DocBook, methods and examples for adding, removing, and modifying elements
    and attributes, and conventions for naming and versioning
    DocBook customizations.
    It assumes some familiarity with RELAX NG.  If you are unfamiliar
    with RELAX NG, you can find a tutorial introduction in
    [<a class="citation" href="#d5e1003"><span class="citation">RNCTUT</span></a>].
  </p>
  <div class="section" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="relaxngorg"></a>DocBook RELAX NG schema organization</h3></div></div></div>
    
    <p>
      The DocBook RELAX NG schema is highly modular, using named
      patterns extensively.  Every element, attribute, attribute
      list, and enumeration has its own named pattern.  In addition,
      there are named patterns for logical combinations of elements
      and attributes.  These named patterns provide &#8220;<span class="quote">hooks</span>&#8221;
      into the schema that allow you to do a wide range of customization
      by simply redefining one or more of the named patterns.
    </p>
    <p>
      An important design characteristic of the schema is that
      duplication is minimized.  This is done through the use of
      named patterns for common groupings that can be re-used.
      For example, the <a href="http://docbook.org/tdg5/en/html/imagedata.html"><code class="sgmltag-element">imagedata</code></a> and <a href="http://docbook.org/tdg5/en/html/videodata.html"><code class="sgmltag-element">videodata</code></a>
      elements each have an <code class="sgmltag-attribute">align</code> attribute
      that takes the same set of enumerated values.  Rather than
      repeating those values, a single pattern,
      <code class="varname">db.halign.enumeration</code> is referenced by
      the <code class="varname">db.videodata.align.enumeration</code>
      and <code class="varname">db.imagedata.align.enumeration</code> patterns,
      which are in turn referenced by the
      <code class="varname">db.videodata.align.attribute</code>
      and <code class="varname">db.imagedata.align.attribute</code> patterns.
      While this may seem like overkill, it allows a customizer to modify
      the allowed enumerations for these two attributes separately or together,
      or to completely re-define the allowed content of either or both,
      by redefining one or more of these named patterns.
    </p>
    <div class="section" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="patternnames"></a>Pattern Names</h4></div></div></div>
    <p>
      Because named patterns are used extensively, the RELAX NG schema uses
      several naming conventions.  These are:
      </p><div class="itemizedlist"><ul type="disc" compact><li>
          <p>
            Names have two or more parts, separated by dots &#8220;<span class="quote">.</span>&#8221;
          </p>
        </li><li>
          <p>
            The first part of each name is the prefix &#8220;<span class="quote">db</span>&#8221;
          </p>
        </li><li>
          <p>
            Each element has a named pattern in the form
            <code class="varname">db.<em class="replaceable"><code>elementname</code></em></code>.
            Elements that have different content models in different
            contexts will also have patterns in the form
            <code class="varname">db.<em class="replaceable"><code>context.elementname</code></em></code>.  For example, <code class="varname">db.figure.info</code>
            defines the content model for the <a href="http://docbook.org/tdg5/en/html/info.html"><code class="sgmltag-element">info</code></a> element
            when it appears as a child of the <a href="http://docbook.org/tdg5/en/html/figure.html"><code class="sgmltag-element">figure</code></a> element.
            <em class="replaceable"><code>Context</code></em> may have several parts.
            For example, <code class="varname">db.cals.entrytbl.thead</code>.
          </p>
        </li><li>
          <p>
            Most attributes have a named pattern in the form
            <code class="varname">db.<em class="replaceable"><code>attributename</code></em>.attribute</code>.
            Attributes that have different content models in different
            contexts will also have patterns in the form
            <code class="varname">db.<em class="replaceable"><code>context.attributename</code></em>.attribute</code>.
            For example,
            <code class="varname">db.olink.localinfo.attribute</code> defines the content
            model of the <code class="sgmltag-attribute">localinfo</code> attribute when
            it appears in <a href="http://docbook.org/tdg5/en/html/olink.html"><code class="sgmltag-element">olink</code></a>.
            There are a few attributes that do not have individual named
            patterns.  For example, the effectivity attributes are grouped
            into <code class="varname">db.effectivity.attributes</code> and not identified
            separately.
          </p>
        </li><li>
          <p>
            Each element has a named pattern for its attribute list in
            the form
            <code class="varname">db.<em class="replaceable"><code>elementname</code></em>.attlist</code>

            that defines the list of attributes for that element.
            Elements that have different attribute lists in different
            contexts will also have patterns in the form
            <code class="varname">db.<em class="replaceable"><code>context.elementname</code></em>.attlist</code>
            For example, <code class="varname">db.html.table.attlist</code> defines
            the attribute list for the html <code class="sgmltag-element">table</code> element and
            <code class="varname">db.cals.table.attlist</code> defines the attribute
            list for a cals <code class="sgmltag-element">table</code> element.
          </p>
        </li><li>
          <p>
            Each attribute that has enumerated values has a
            named pattern in the form
            <code class="varname">db.<em class="replaceable"><code>[context.]attributename</code></em>.enumeration</code>.
            If the enumeration for a particular attribute depends on
            context, optional context is provided.
            For example,
            <code class="varname">db.verbatim.continuation.enumeration</code> defines
            the enumeration values for the
            <code class="sgmltag-attribute">continuation</code> attribute that is used
            in verbatim contexts like <a href="http://docbook.org/tdg5/en/html/screen.html"><code class="sgmltag-element">screen</code></a>.
            Unlike elements and attributes, there is not necessarily a
            named pattern for enumerated attributes outside their context.
            For example, there is no <code class="varname">db.class.enumeration</code>
            because the <code class="sgmltag-attribute">class</code> attribute has
            a broad and non-intersecting range of uses.
          </p>
        </li><li>
          <p>
            There are several different groupings of elements and attributes.
            Here are the major ones:
            </p><div class="variablelist"><dl><dt><span class="term">inlines</span></dt><dd>
                  <p>
                    Combinations of inline elements, for example,
                    <code class="varname">db.error.inlines</code>, which contains
                    <code class="varname">db.errorcode</code>,
                    <code class="varname">db.errortext</code>, etc.
                  </p>
                </dd><dt><span class="term">blocks</span></dt><dd>
                  <p>
                    Combinations of block elements, for example,
                    <code class="varname">db.verbatim.blocks</code>, which contains
                    <code class="varname">db.programlisting</code>,
                    <code class="varname">db.screen</code>, etc.
                  </p>
                </dd><dt><span class="term">attributes</span></dt><dd>
                  <p>
                    Combinations of attributes, for example,
                    <code class="varname">db.effectivity.attributes</code>,
                    which contains the attributes
                    <code class="sgmltag-attribute">arch</code>,
                    <code class="sgmltag-attribute">condition</code>,
                    <code class="sgmltag-attribute">conformance</code>, etc.
                  </p>
                </dd><dt><span class="term">components</span></dt><dd>
                  <p>
                    High level components of the schema, for example,
                    <code class="varname">db.navigation.components</code>, which contains
                    <code class="varname">db.glossary</code>,
                    <code class="varname">db.bibliography</code>,
                    <code class="varname">db.index</code>, and
                    <code class="varname">db.toc</code>, and is used inside the
                    content model for <a href="http://docbook.org/tdg5/en/html/chapter.html"><code class="sgmltag-element">chapter</code></a>, <a href="http://docbook.org/tdg5/en/html/appendix.html"><code class="sgmltag-element">appendix</code></a>,
                    and <a href="http://docbook.org/tdg5/en/html/preface.html"><code class="sgmltag-element">preface</code></a>.
                  </p>
                </dd><dt><span class="term">contentmodel</span></dt><dd>
                  <p>
                    Shared content models, for example,
                    <code class="varname">db.admonition.contentmodel</code>, which contains
                    the content model for <a href="http://docbook.org/tdg5/en/html/tip.html"><code class="sgmltag-element">tip</code></a>, <a href="http://docbook.org/tdg5/en/html/warning.html"><code class="sgmltag-element">warning</code></a>,
                    <a href="http://docbook.org/tdg5/en/html/note.html"><code class="sgmltag-element">note</code></a>, etc.
                  </p>
                </dd></dl></div><p>
          </p>
          <p>
            There are a couple of other groupings designed to minimize
            duplication, but these are the most important.
          </p>
        </li></ul></div><p>
    </p>
  </div>
</div>
<div class="section" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="customconsiderations"></a>General customization considerations</h3></div></div></div>
  
  <p>
    Creating a customized schema is similar to
    creating a customization layer for XSL.  The schema customization
    layer is a new RELAX NG schema that defines your changes and
    includes the standard docbook schema.  You then validate using
    the schema customization as your schema.
  </p>
  <p>
    <a class="xref" href="#ex-empty" title="Example&nbsp;3.&nbsp;Empty customization file">Example&nbsp;3</a> is an empty
    RELAX NG customization that does nothing
    except define the name spaces and include the standard DocBook schema.
    The <code class="sgmltag-attribute">href</code> attribute of the
    <code class="sgmltag-element">include</code> element points to
    the location of the standard DocBook V5.0
    schema.<sup>[<a name="d5e711" href="#ftn.d5e711" class="footnote">1</a>]</sup>
    All of the examples are given in both RNG and RNC form.
</p><div class="example"><a name="ex-empty"></a><p class="title"><b>Example&nbsp;3.&nbsp;Empty customization file</b></p><div class="example-contents">
<pre class="programlisting"><span class="rolelabel">r<br>n<br>g</span>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
&lt;grammar xmlns:db="http://docbook.org/ns/docbook"
         ns="http://docbook.org/ns/docbook"
         xmlns="http://relaxng.org/ns/structure/1.0"&gt;
  &lt;include href="docbook.rng"/&gt;

  &lt;!-- redefinitions of named patterns --&gt;

&lt;/grammar&gt;</pre>
<pre class="programlisting"><span class="rolelabel">r<br>n<br>c</span>namespace db = "http://docbook.org/ns/docbook"

include "docbook.rnc" inherit = db
# redefinitions of named patterns</pre>
</div></div><p><br class="example-break">
  </p>
</div>
  <div class="section" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="cust-elements"></a>Elements</h3></div></div></div>
    
    <div class="section" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="cust-add-elements"></a>Adding elements</h4></div></div></div>
      
      <p>
        Adding an element typically takes two definitions.
        The first defines the new element and
        its content model, and the second adds the
        new element into the schema.  We'll show two examples.
      </p>
      <p>
        <a class="xref" href="#ex-add-element-1" title="Example&nbsp;4.&nbsp;Adding a new element by duplicating an existing one">Example&nbsp;4</a>
        adds a new element,
        <code class="sgmltag-element">person</code>, with the same
        content model as <a href="http://docbook.org/tdg5/en/html/author.html"><code class="sgmltag-element">author</code></a>.  The new element will be
        allowed to appear wherever <a href="http://docbook.org/tdg5/en/html/author.html"><code class="sgmltag-element">author</code></a> can appear.
      </p>
      <p>
        The <code class="varname">db.author</code> pattern is copied
        and renamed <code class="varname">dbx.person</code>, defining
        a new element called <code class="sgmltag-element">person</code>.
        Then, the <code class="varname">db.author</code> pattern is redefined
        to be a choice of the current value or <code class="varname">dbx.person</code>.
        The <code class="sgmltag-attribute">combine</code> attribute tells
        RELAX NG to combine this pattern with the existing named
        pattern.  In this case, the value
        of the <code class="sgmltag-attribute">combine</code> attribute is
        &#8220;<span class="quote">choice</span>&#8221;, which tells the parser that either
        the original pattern or this new pattern is a valid match.
      </p>
<div class="example"><a name="ex-add-element-1"></a><p class="title"><b>Example&nbsp;4.&nbsp;Adding a new element by duplicating an existing one</b></p><div class="example-contents">
<pre class="programlisting"><span class="rolelabel">r<br>n<br>g</span>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
&lt;grammar xmlns:db="http://docbook.org/ns/docbook"
         ns="http://docbook.org/ns/docbook"
         xmlns="http://relaxng.org/ns/structure/1.0"&gt;
  &lt;include href="docbook.rng"/&gt;
  &lt;!-- define the new element --&gt;
  &lt;define name="dbx.person"&gt;
    &lt;element name="person"&gt;
        &lt;ref name="db.author.attlist"/&gt;
        &lt;ref name="db.credit.contentmodel"/&gt;
    &lt;/element&gt;
  &lt;/define&gt;
  &lt;!-- redefine the db.author pattern to allow db.person in
       the same places as db.author --&gt;
  &lt;define name="db.author" combine="choice"&gt;
    &lt;ref name="dbx.person"/&gt;
  &lt;/define&gt;
&lt;/grammar&gt;</pre>
<pre class="programlisting"><span class="rolelabel">r<br>n<br>c</span>default namespace db = "http://docbook.org/ns/docbook"

include "docbook.rnc"
# define the new element
dbx.person =
  element person { db.author.attlist, db.credit.contentmodel }
# redefine the db.author pattern to allow db.person in
# the same places as db.author
db.author |= dbx.person</pre>
</div></div><br class="example-break">
    <p>
      The preceding method works well when you'd like a new element
      to be a clone or near-clone of an existing element.  It gives
      you complete control over the content model, but
      only limited control over where the element is allowed.  It
      works well when you want to allow the element in the same places
      as an existing element, and for this example that works
      nicely, since <a href="http://docbook.org/tdg5/en/html/author.html"><code class="sgmltag-element">author</code></a> is allowed in four different
      named patterns, each of which would have had to be redefined to
      allow <code class="sgmltag-element">person</code>.
      But, if you can't find an existing element that is allowed in
      exactly the places you need, this method doesn't work as well.
    </p>
    <p>
      <a class="xref" href="#ex-add-element-2" title="Example&nbsp;5.&nbsp;Adding new inline elements">Example&nbsp;5</a>
      adds two new elements by combining them into
      a higher level pattern.  In this example, we'll add
      two new inline elements for writing about assembly language,
      <code class="sgmltag-element">register</code> and 
      <code class="sgmltag-element">instruction</code>.
      We will allow them wherever programming inlines
      or operating system inlines are allowed.
      <a class="xref" href="#ex-add-element-2" title="Example&nbsp;5.&nbsp;Adding new inline elements">Example&nbsp;5</a>
      defines the two elements, creates a new named pattern
      (<code class="varname">dbx.asm.inlines</code>) that contains them, and adds
      that pattern to <code class="varname">db.programming.inlines</code> and
      <code class="varname">db.os.inlines</code>.  Since these two patterns
      don't have any elements in common, the strategy used in 
      <a class="xref" href="#ex-add-element-1" title="Example&nbsp;4.&nbsp;Adding a new element by duplicating an existing one">Example&nbsp;4</a>
      would require selecting two different elements to &#8220;<span class="quote">clone</span>&#8221;,
      which would be messy.
    </p>
<div class="example"><a name="ex-add-element-2"></a><p class="title"><b>Example&nbsp;5.&nbsp;Adding new inline elements</b></p><div class="example-contents">
<pre class="programlisting"><span class="rolelabel">r<br>n<br>g</span>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
&lt;grammar xmlns:db="http://docbook.org/ns/docbook"
         ns="http://docbook.org/ns/docbook"
         xmlns="http://relaxng.org/ns/structure/1.0"&gt;
  &lt;include href="docbook.rng"/&gt;
  &lt;!-- define the new elements --&gt;
  &lt;define name="dbx.register"&gt;
    &lt;element name="register"&gt;
      &lt;text/&gt;
    &lt;/element&gt;
  &lt;/define&gt;
  &lt;define name="dbx.instruction"&gt;
    &lt;element name="instruction"&gt;
      &lt;text/&gt;
    &lt;/element&gt;
  &lt;/define&gt;
  &lt;!-- create a new pattern that contains the new inlines --&gt;
  &lt;define name="dbx.asm.inlines"&gt;
    &lt;choice&gt;
      &lt;ref name="dbx.register"/&gt;
      &lt;ref name="dbx.instruction"/&gt;
    &lt;/choice&gt;
  &lt;/define&gt;
  &lt;!-- add the new inlines to programming and os inlines --&gt;
    &lt;define name="db.programming.inlines" combine="choice"&gt;
      &lt;ref name="dbx.asm.inlines"/&gt;
    &lt;/define&gt;
    &lt;define name="db.os.inlines" combine="choice"&gt;
      &lt;ref name="dbx.asm.inlines"/&gt;
    &lt;/define&gt;
&lt;/grammar&gt;</pre>
<pre class="programlisting"><span class="rolelabel">r<br>n<br>c</span>default namespace db = "http://docbook.org/ns/docbook"

include "docbook.rnc"
# define the new elements
dbx.register = element register { text }
dbx.instruction = element instruction { text }
# create a new pattern that contains the new inlines
dbx.asm.inlines = dbx.register | dbx.instruction
# add the new inlines to programming and os inlines
db.programming.inlines |= dbx.asm.inlines
db.os.inlines |= dbx.asm.inlines</pre>
</div></div><br class="example-break">
    </div>
    <div class="section" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="cust-delete-elements"></a>Deleting elements</h4></div></div></div>
      
      <p>
        Deleting elements is straightforward, but takes some
        care and planning.  <a class="xref" href="#ex-delete-element" title="Example&nbsp;6.&nbsp;Deleting an element">Example&nbsp;6</a> deletes
        the <a href="http://docbook.org/tdg5/en/html/important.html"><code class="sgmltag-element">important</code></a> admonition element by redefining
        it with a content model of <code class="varname">notAllowed</code>.
        Note that in this example, the redefinition is inside
        the <code class="sgmltag-element">include</code> element.
        This is required for
        redefinitions that completely replace an existing pattern.
      </p>
      <p>
        Be careful; If you delete an element that is a required part
        of another element's content model, you can make it
        impossible to create a valid document.
        For example, if you delete the <a href="http://docbook.org/tdg5/en/html/title.html"><code class="sgmltag-element">title</code></a>
        element, you won't be able to validate a <a href="http://docbook.org/tdg5/en/html/book.html"><code class="sgmltag-element">book</code></a>
        because a <a href="http://docbook.org/tdg5/en/html/book.html"><code class="sgmltag-element">book</code></a> requires a <a href="http://docbook.org/tdg5/en/html/title.html"><code class="sgmltag-element">title</code></a>.
      </p>
<div class="example"><a name="ex-delete-element"></a><p class="title"><b>Example&nbsp;6.&nbsp;Deleting an element</b></p><div class="example-contents">
<pre class="programlisting"><span class="rolelabel">r<br>n<br>g</span>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
&lt;grammar xmlns:db="http://docbook.org/ns/docbook"
         ns="http://docbook.org/ns/docbook"
         xmlns="http://relaxng.org/ns/structure/1.0"&gt;
  &lt;include href="docbook.rng"&gt;
    &lt;!-- redefine important element as notAllowed --&gt;
    &lt;define name="db.important"&gt;
      &lt;notAllowed/&gt;
    &lt;/define&gt;
  &lt;/include&gt;
&lt;/grammar&gt;</pre>
<pre class="programlisting"><span class="rolelabel">r<br>n<br>c</span>namespace db = "http://docbook.org/ns/docbook"

include "docbook.rnc" inherit = db {
  # redefine important element as notAllowed
  db.important = notAllowed
}</pre>
</div></div><br class="example-break">
    </div>
    <div class="section" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="cust-modify-elements"></a>Customizing the content model of existing elements</h4></div></div></div>
      
      <p>
         <a class="xref" href="#ex-modify-element" title="Example&nbsp;7.&nbsp;Modifying the content model of an element">Example&nbsp;7</a>
         expands the definition of <a href="http://docbook.org/tdg5/en/html/author.html"><code class="sgmltag-element">author</code></a> to include two
         new elements, <code class="sgmltag-element">born</code> and
         <code class="sgmltag-element">died</code>.
         The <a href="http://docbook.org/tdg5/en/html/author.html"><code class="sgmltag-element">author</code></a> element allows two content models,
         <code class="varname">db.person.author.contentmodel</code>, which
         defines an author who is a person, and
         <code class="varname">db.org.author.contentmodel</code>, which
         defines an author that is an organization.  We will modify
         <code class="varname">db.person.author.contentmodel</code> so that
         only authors who are persons can have the new elements.
</p><div class="example"><a name="ex-modify-element"></a><p class="title"><b>Example&nbsp;7.&nbsp;Modifying the content model of an element</b></p><div class="example-contents">
<pre class="programlisting"><span class="rolelabel">r<br>n<br>g</span>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
&lt;grammar xmlns:db="http://docbook.org/ns/docbook"
         ns="http://docbook.org/ns/docbook"
         xmlns="http://relaxng.org/ns/structure/1.0"&gt;
  &lt;include href="docbook.rng"/&gt;

  &lt;define name="db.person.author.contentmodel" combine="interleave"&gt;
    &lt;interleave&gt;
      &lt;optional&gt;
        &lt;element name="born"&gt;
          &lt;ref name="db.date.contentmodel"/&gt;
        &lt;/element&gt;
      &lt;/optional&gt;
      &lt;optional&gt;
        &lt;element name="died"&gt;
          &lt;ref name="db.date.contentmodel"/&gt;
        &lt;/element&gt;
      &lt;/optional&gt;
    &lt;/interleave&gt;
  &lt;/define&gt;
&lt;/grammar&gt;</pre>
<pre class="programlisting"><span class="rolelabel">r<br>n<br>c</span>default namespace = "http://docbook.org/ns/docbook"
namespace db = "http://docbook.org/ns/docbook"

include "docbook.rnc"

db.person.author.contentmodel &amp;=
  element born { db.date.contentmodel }?
  &amp; element died { db.date.contentmodel }?</pre>
</div></div><p><br class="example-break">
      </p>
      <p>
        This modification will allow instances like this:
</p><pre class="programlisting">&lt;author&gt;
  &lt;personname&gt;Babe Ruth&lt;/personname&gt;
  &lt;born&gt;02/06/1895&lt;/born&gt;
  &lt;died&gt;08/16/1948&lt;/died&gt;
&lt;/author&gt;</pre><p>
but because we only modified the content model for authors
who are human, it won't allow an instance like this, which
uses <code class="varname">db.org.author.contentmodel</code>:
</p><pre class="programlisting">&lt;!-- INVALID --&gt;
&lt;author&gt;
  &lt;orgname&gt;Boston Red Sox&lt;/orgname&gt;
  &lt;died&gt;1919&lt;/died&gt;
  &lt;born&gt;2004&lt;/born&gt;
&lt;/author&gt;</pre><p>
      </p>
    </div>
  </div>
  <div class="section" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="cust-attributes"></a>Attributes</h3></div></div></div>
    
    <div class="section" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="cust-add-attributes"></a>Adding attributes</h4></div></div></div>
      
      <p>
        The simplest way to add an attribute to a single element
        is to add it to the attlist pattern for that element.
        <a class="xref" href="#ex-add-attr" title="Example&nbsp;8.&nbsp;Adding attributes">Example&nbsp;8</a>
        adds the optional attributes <code class="sgmltag-attribute">born</code>
        and <code class="sgmltag-attribute">died</code> to the attribute
        list for <a href="http://docbook.org/tdg5/en/html/author.html"><code class="sgmltag-element">author</code></a>.
        The <code class="varname">db.author.attlist</code>
        named pattern is redefined with the
        <code class="sgmltag-attribute">combine</code> attribute set to
        &#8220;<span class="quote">interleave</span>&#8221;, which interleaves the two new
        optional attributes with the existing attributes on the list.
      </p>
<div class="example"><a name="ex-add-attr"></a><p class="title"><b>Example&nbsp;8.&nbsp;Adding attributes</b></p><div class="example-contents">
<pre class="programlisting"><span class="rolelabel">r<br>n<br>g</span>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
&lt;grammar xmlns:db="http://docbook.org/ns/docbook"
         ns="http://docbook.org/ns/docbook"
         xmlns="http://relaxng.org/ns/structure/1.0"&gt;
  &lt;include href="docbook.rng"/&gt;

  &lt;define name="db.author.attlist" combine="interleave"&gt;
    &lt;interleave&gt;
      &lt;optional&gt;
        &lt;attribute name="born"&gt;
          &lt;ref name="db.date.contentmodel"/&gt;
        &lt;/attribute&gt;
      &lt;/optional&gt;
      &lt;optional&gt;
        &lt;attribute name="died"&gt;
          &lt;ref name="db.date.contentmodel"/&gt;
        &lt;/attribute&gt;
      &lt;/optional&gt;
    &lt;/interleave&gt;
  &lt;/define&gt;
&lt;/grammar&gt;</pre>
<pre class="programlisting"><span class="rolelabel">r<br>n<br>c</span>namespace db = "http://docbook.org/ns/docbook"

include "docbook.rnc" inherit = db

db.author.attlist &amp;=
  attribute born { db.date.contentmodel }?
  &amp; attribute died { db.date.contentmodel }?</pre>
</div></div><br class="example-break">
    <p>
      Unlike
      <a class="xref" href="#ex-modify-element" title="Example&nbsp;7.&nbsp;Modifying the content model of an element">Example&nbsp;7</a>,
      <a class="xref" href="#ex-add-attr" title="Example&nbsp;8.&nbsp;Adding attributes">Example&nbsp;8</a> allows
      the new attributes to appear on any <a href="http://docbook.org/tdg5/en/html/author.html"><code class="sgmltag-element">author</code></a>
      element, not just those using the person content model.
    </p>
    <p>
      <a class="xref" href="#ex-add-attr-2" title="Example&nbsp;9.&nbsp;Adding attributes; alternate method">Example&nbsp;9</a> shows
      how you could limit the use of these attributes to authors who
      are persons.  In this example, the new attributes are interleaved
      with the <code class="varname">db.person.author.contentmodel</code>.  
      The only difference between this example and 
      <a class="xref" href="#ex-modify-element" title="Example&nbsp;7.&nbsp;Modifying the content model of an element">Example&nbsp;7</a> is
      that the added patterns are identified as attributes rather than
      elements.  This shows some of the flexibility of RELAX NG, which
      treats attributes and elements very consistently.
</p><div class="example"><a name="ex-add-attr-2"></a><p class="title"><b>Example&nbsp;9.&nbsp;Adding attributes; alternate method</b></p><div class="example-contents">
<pre class="programlisting"><span class="rolelabel">r<br>n<br>g</span>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
&lt;grammar xmlns:db="http://docbook.org/ns/docbook"
         ns="http://docbook.org/ns/docbook"
         xmlns="http://relaxng.org/ns/structure/1.0"&gt;
  &lt;include href="docbook.rng"/&gt;
  &lt;!-- redefinitions of named patterns --&gt;
  &lt;define name="db.person.author.contentmodel" combine="interleave"&gt;
    &lt;interleave&gt;
      &lt;optional&gt;
        &lt;attribute name="born"&gt;
          &lt;ref name="db.date.contentmodel"/&gt;
        &lt;/attribute&gt;
      &lt;/optional&gt;
      &lt;optional&gt;
        &lt;attribute name="died"&gt;
          &lt;ref name="db.date.contentmodel"/&gt;
        &lt;/attribute&gt;
      &lt;/optional&gt;
    &lt;/interleave&gt;
  &lt;/define&gt;
&lt;/grammar&gt;</pre>
<pre class="programlisting"><span class="rolelabel">r<br>n<br>c</span>namespace db = "http://docbook.org/ns/docbook"

include "docbook.rnc" inherit = db
# redefinitions of named patterns
db.person.author.contentmodel &amp;=
  attribute born { db.date.contentmodel }?
  &amp; attribute died { db.date.contentmodel }?</pre>
</div></div><p><br class="example-break">
There is one difference in the treatment of attributes and elements
that is worth noting.  By the XML 1.0 definition, the relative order
of attributes is not significant.  Therefore, the
<code class="sgmltag-element">interleave</code> block is not required for
attributes, though it does no harm.  
    </p>
    </div>
    <div class="section" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="cust-delete-attributes"></a>Deleting attributes</h4></div></div></div>
      
      <p>
        Deleting an attribute is similar to deleting an element,
        except that you use the RELAX NG <code class="varname">empty</code>
        pattern rather than <code class="varname">notAllowed</code>.
        <a class="xref" href="#ex-delete-attr" title="Example&nbsp;10.&nbsp;Deleting an attribute">Example&nbsp;10</a>
        deletes the linking attributes, which are collected in the
        <code class="varname">db.common.linking.attributes</code> pattern,
        by defining that pattern as <code class="varname">empty</code>.
      </p>
<div class="example"><a name="ex-delete-attr"></a><p class="title"><b>Example&nbsp;10.&nbsp;Deleting an attribute</b></p><div class="example-contents">
<pre class="programlisting"><span class="rolelabel">r<br>n<br>g</span>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
&lt;grammar xmlns:db="http://docbook.org/ns/docbook"
         ns="http://docbook.org/ns/docbook"
         xmlns="http://relaxng.org/ns/structure/1.0"&gt;
  &lt;include href="docbook.rng"&gt;
    &lt;define name="db.common.linking.attributes"&gt;
      &lt;empty/&gt;
    &lt;/define&gt;
  &lt;/include&gt;
&lt;/grammar&gt;</pre>
<pre class="programlisting"><span class="rolelabel">r<br>n<br>c</span>namespace db = "http://docbook.org/ns/docbook"

include "docbook.rnc" inherit = db {
  db.common.linking.attributes = empty
}</pre>
</div></div><br class="example-break">
      <p>
        Generally, <code class="varname">empty</code> is used when deleting
        attributes and <code class="varname">notAllowed</code> is used when
        deleting elements.
      </p>
    </div>
    <div class="section" lang="en"><div class="titlepage"><div><div><h4 class="title"><a name="cust-modify-attributes"></a>Changing permitted content of attributes</h4></div></div></div>
      
      <p>
        <a class="xref" href="#ex-modify-attr" title="Example&nbsp;11.&nbsp;Deleting an attribute">Example&nbsp;11</a>
        modifies <code class="varname">db.spacing.enumeration</code> to
        add the additional value &#8220;<span class="quote">large</span>&#8221;.  Note
        that to remove a value from an enumeration, you need
        to redefine the entire enumeration, minus the values
        you don't need.
      </p>
<div class="example"><a name="ex-modify-attr"></a><p class="title"><b>Example&nbsp;11.&nbsp;Deleting an attribute</b></p><div class="example-contents">
<pre class="programlisting"><span class="rolelabel">r<br>n<br>g</span>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
&lt;grammar xmlns:db="http://docbook.org/ns/docbook"
         ns="http://docbook.org/ns/docbook"
         xmlns="http://relaxng.org/ns/structure/1.0"&gt;
  &lt;include href="docbook.rng"/&gt;
  &lt;!-- add value to an enumeration --&gt;
  &lt;define name="db.spacing.enumeration" combine="choice"&gt;
    &lt;value&gt;large&lt;/value&gt;
  &lt;/define&gt;
&lt;/grammar&gt;</pre>
<pre class="programlisting"><span class="rolelabel">r<br>n<br>c</span>namespace db = "http://docbook.org/ns/docbook"

include "docbook.rnc" inherit = db
# add value to an enumeration
db.spacing.enumeration |= "large"</pre>
</div></div><br class="example-break">
    </div>
  </div>

<div class="section" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="cust-naming"></a>Naming and versioning DocBook customizations</h3></div></div></div>


<p>DocBook V5.0 is not tightly coupled with some particular
validation technology like DTDs. This also means that DocBook V5.0
documents don't have to (and usually don't) start with a
document type declaration (&lt;!DOCTYPE&#8230;&gt;) to specify the schema
(DTD) to use. Instead, DocBook V5.0 instances can be easily
distinguished from other XML vocabularies by using elements in the
<code class="uri">http://docbook.org/ns/docbook</code> namespace. This namespace is
enough to distinguish DocBook from other XML based formats. But the
DocBook schema evolves over time and there are several versions of
DocBook (e.g. 3.1, 4.2, 4.5 and 5.0).  Since DocBook version 5.0, the
actual version used is indicated in the <code class="sgmltag-attribute">version</code> attribute on a root element.</p>

<pre class="programlisting">&lt;book xmlns="http://docbook.org/ns/docbook"
      version="5.0"&gt;
  &#8230;
&lt;/book&gt;</pre>

<p>Future versions of DocBook documents will start with the same
markup, except the version number will be raised, for example to 5.1
or 6.0.
The namespace will remain the same until the semantics of the elements
change in a backward incompatible way, which is very unlikely to happen.</p>

<p>If you create a DocBook schema customization you must change the <code class="sgmltag-attribute">version</code> attribute to distinguish your
customization from the &#8220;<span class="quote">official</span>&#8221; DocBook.  Changing the
namespace is not recommended because that would break the processing
tools.  Remember that changing namespaces is the same as renaming all
elements in the namespace.</p>

<p>When you customize the schema, use the following syntax to
identify your DocBook derivation:</p>

<pre class="programlisting"><em class="replaceable"><code>base_version</code></em>-[subset|extension|variant] [<em class="replaceable"><code>name</code></em>[-<em class="replaceable"><code>version</code></em>]?]+</pre>

<p>For example:</p>

<pre class="programlisting">5.0-subset simplified-1.0
5.0-variant ASMBook
5.0-variant ASMBook-2006
5.0-extension MathML-2.0 SVG-1.1</pre>

<p>The first part of the version identifier is the version number of the
DocBook schema from which you derived your customization.</p>

<p>If your schema is a proper subset, you can advertise this status
by using the <code class="literal">subset</code> keyword in the description. If
your schema contains any markup model extensions, you can advertise
this status by using the <code class="literal">extension</code> keyword. If
you'd rather not characterize your variant specifically as a subset or
an extension, use the <code class="literal">variant</code> keyword.</p>

<p>After these keywords you may add a whitespace separated list of
customization identifiers. Each name may be optionally followed by its
version number.</p>

</div>

</div>

<div class="section" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="faq"></a>FAQ</h2></div></div></div>


<div class="qandaset"><dl><dt>1.  <a href="#d5e875">Authoring</a></dt><dd><dl><dt>1.1. <a href="#faq-authoring-schema-association">How do I attach a schema to a DocBook V5.0 document when I do not
want to use DTDs and !DOCTYPE?</a></dt><dt>1.2. <a href="#faq-authoring-general-entities">How do I use entities like &amp;ndash; in
DocBook V5.0?</a></dt><dt>1.3. <a href="#faq-authoring-modularization">How to modularize documents?</a></dt><dt>1.4. <a href="#faq-authoring-validating-xincludes">How to validate documents which are composed by XInclude?</a></dt></dl></dd><dt>2.  <a href="#d5e913">Stylesheets</a></dt><dd><dl><dt>2.1. <a href="#faq-stylesheets-future">Will the current DocBook XSL stylesheets (XSLT 1.0 based
implementation) be maintained and improved in the future since work on
a new XSLT 2.0 based implementation has started?</a></dt></dl></dd><dt>3.  <a href="#d5e921">Schema customizations</a></dt><dd><dl><dt>3.1. <a href="#faq-customization-mathml">How can I extend the DocBook schema with MathML elements?</a></dt><dt>3.2. <a href="#faq-customization-svg">How can I extend the DocBook schema with SVG elements?</a></dt><dt>3.3. <a href="#faq-customization-mathml-svg">Is it possible to use the previous two customizations for MathML
and SVG together?</a></dt><dt>3.4. <a href="#faq-customization-links">Are there any other examples of schema customization
available?</a></dt></dl></dd><dt>4.  <a href="#d5e990">Tool specific problems</a></dt><dd><dl><dt>4.1. <a href="#faq-tools-xmlspy-xmlid">I'm using Altova XMLSpy to validate DocBook V5.0 instances
against the W3C XML Schema (docbook.xsd). XMLSpy
complains about undefined xml:id
attributes?</a></dt></dl></dd></dl><table border="0" summary="Q and A Set"><col align="left" width="1%"><tbody><tr class="qandadiv"><td align="left" valign="top" colspan="2"><h4 class="title"><a name="d5e875"></a>1. Authoring</h4></td></tr><tr class="toc"><td align="left" valign="top" colspan="2"><dl><dt>1.1. <a href="#faq-authoring-schema-association">How do I attach a schema to a DocBook V5.0 document when I do not
want to use DTDs and !DOCTYPE?</a></dt><dt>1.2. <a href="#faq-authoring-general-entities">How do I use entities like &amp;ndash; in
DocBook V5.0?</a></dt><dt>1.3. <a href="#faq-authoring-modularization">How to modularize documents?</a></dt><dt>1.4. <a href="#faq-authoring-validating-xincludes">How to validate documents which are composed by XInclude?</a></dt></dl></td></tr>
<tr class="question"><td align="left" valign="top"><a name="faq-authoring-schema-association"></a><a name="d5e878"></a><p><b>1.1.</b></p></td><td align="left" valign="top"><p>How do I attach a schema to a DocBook V5.0 document when I do not
want to use DTDs and !DOCTYPE?</p></td></tr>
<tr class="answer"><td align="left" valign="top"></td><td align="left" valign="top"><p>There is no standard way of associating a RELAX NG schema with a
document. Most tools provide some mechanism for performing this
association, consult the documentation for your application. In some
tools you must specify schema manually each time you want to
edit/process your document.</p></td></tr>

<tr class="question"><td align="left" valign="top"><a name="faq-authoring-general-entities"></a><a name="d5e883"></a><p><b>1.2.</b></p></td><td align="left" valign="top"><p>How do I use entities like <code class="sgmltag-genentity">&amp;ndash;</code> in
DocBook V5.0?</p></td></tr>
<tr class="answer"><td align="left" valign="top"></td><td align="left" valign="top"><p>Modern schema languages (including RELAX NG and W3X XML Schema)
do not provide any means to define entities that can be used for easier
typing of special characters. Some editors provide functions or
special toolbars that allow you to easily pick necessary character
and insert it into document as a raw Unicode character or a numeric
character reference.</p><p>Another possibility is to include entity definitions in the
prolog of your document. <a class="link" href="http://www.w3.org/2003/entities/" target="_top">Entity definition
files</a> are now maintained by W3C. You can reference definition
files with entity definitions you are interested in and then reference
imported entities. For example:</p><pre class="programlisting">&lt;?xml version="1.0" encoding="utf-8"?&gt;
&lt;!DOCTYPE article [
&lt;!ENTITY % isopub SYSTEM "http://www.w3.org/2003/entities/iso8879/isopub.ent"&gt;
%isopub;
]&gt;
&lt;article xmlns="http://docbook.org/ns/docbook" version="5.0"&gt;
&lt;title&gt;DocBook V5.0 &amp;ndash; the superb documentation format&lt;/title&gt;
&#8230;</pre><p>For your convenience there is also flattened entity definition
file which contains all entity definitions.</p><pre class="programlisting">&lt;?xml version="1.0" encoding="utf-8"?&gt;
&lt;!DOCTYPE article [
&lt;!ENTITY % allent SYSTEM "http://www.w3.org/2003/entities/2007/w3centities-f.ent"&gt;
%allent;
]&gt;
&lt;article xmlns="http://docbook.org/ns/docbook" version="5.0"&gt;
&lt;title&gt;DocBook V5.0 &amp;ndash; the superb documentation format&lt;/title&gt;
&#8230;</pre></td></tr>

<tr class="question"><td align="left" valign="top"><a name="faq-authoring-modularization"></a><a name="d5e894"></a><p><b>1.3.</b></p></td><td align="left" valign="top"><p>How to modularize documents?</p></td></tr>
<tr class="answer"><td align="left" valign="top"></td><td align="left" valign="top"><p>You can use <a class="link" href="http://www.w3.org/TR/xinclude/" target="_top">XInclude</a> for this
task. There is an alternative schema for DocBook V5.0 that
contains XInclude elements. This is necessary to make some XML editors
happy. This schema can be found in files that end with letters &#8220;<span class="quote">xi</span>&#8221;, e.g.
<code class="filename">docbookxi.rnc</code> instead of
<code class="filename">docbook.rnc</code>.</p></td></tr>

<tr class="question"><td align="left" valign="top"><a name="faq-authoring-validating-xincludes"></a><a name="d5e903"></a><p><b>1.4.</b></p></td><td align="left" valign="top"><p>How to validate documents which are composed by XInclude?</p></td></tr>
<tr class="answer"><td align="left" valign="top"></td><td align="left" valign="top"><p>If you are using XIncludes you should make sure that the final
document after resolving all inclusions is valid DocBook V5.0
instance. This means that all XIncludes should be processed before
validation takes place. The following command can be used to enable
XInclude processing in oNVDL.</p><pre class="screen"><span class="command"><strong>java</strong></span> -Dorg.apache.xerces.xni.parser.XMLParserConfiguration=org.apache.xerces.parsers.XIncludeParserConfiguration -jar <em class="replaceable"><code>/path/to/oNVDL/</code></em>bin/onvdl.jar <em class="replaceable"><code>/path/to/</code></em>docbook.nvdl document.xml</pre><p>For JNVDL you can use switch <code class="option">-xi</code> to enable XInclude processing.</p></td></tr>
<tr class="qandadiv"><td align="left" valign="top" colspan="2"><h4 class="title"><a name="d5e913"></a>2. Stylesheets</h4></td></tr><tr class="toc"><td align="left" valign="top" colspan="2"><dl><dt>2.1. <a href="#faq-stylesheets-future">Will the current DocBook XSL stylesheets (XSLT 1.0 based
implementation) be maintained and improved in the future since work on
a new XSLT 2.0 based implementation has started?</a></dt></dl></td></tr>
<tr class="question"><td align="left" valign="top"><a name="faq-stylesheets-future"></a><a name="d5e916"></a><p><b>2.1.</b></p></td><td align="left" valign="top"><p>Will the current DocBook XSL stylesheets (XSLT 1.0 based
implementation) be maintained and improved in the future since work on
a new XSLT 2.0 based implementation has started?</p></td></tr>
<tr class="answer"><td align="left" valign="top"></td><td align="left" valign="top"><p>Yes, the current stylesheets (like 1.73.x) will be supported and
improved further because they are very widely deployed and work with
many existing XSLT processors.</p><p>Surely there will be a point in a future when all new development
will be switched to the XSLT 2.0 based implementation. But this
will not happen until all features of the current stylesheets are
implemented in the new stylesheets, and until there is more than
one usable XSLT 2.0 processor available.</p></td></tr>
<tr class="qandadiv"><td align="left" valign="top" colspan="2"><h4 class="title"><a name="d5e921"></a>3. Schema customizations</h4></td></tr><tr class="toc"><td align="left" valign="top" colspan="2"><dl><dt>3.1. <a href="#faq-customization-mathml">How can I extend the DocBook schema with MathML elements?</a></dt><dt>3.2. <a href="#faq-customization-svg">How can I extend the DocBook schema with SVG elements?</a></dt><dt>3.3. <a href="#faq-customization-mathml-svg">Is it possible to use the previous two customizations for MathML
and SVG together?</a></dt><dt>3.4. <a href="#faq-customization-links">Are there any other examples of schema customization
available?</a></dt></dl></td></tr>
<tr class="question"><td align="left" valign="top"><a name="faq-customization-mathml"></a><a name="d5e924"></a><p><b>3.1.</b></p></td><td align="left" valign="top"><p>How can I extend the DocBook schema with MathML elements?</p></td></tr>
<tr class="answer"><td align="left" valign="top"></td><td align="left" valign="top"><p>The basic DocBook schema allows elements from the MathML namespace
to appear inside the <a href="http://docbook.org/tdg5/en/html/equation.html"><code class="sgmltag-element">equation</code></a> element.  This means that you can
validate a DocBook+MathML document, but MathML content will be ignored
during the validation. You will also not be able to use guided editing
for the MathML content.</p><p>If you need strict validation of MathML content or guided
editing for MathML, you can easily extend the base DocBook schema with
the MathML schema.</p><div class="procedure"><a name="d5e930"></a><p class="title"><b>Procedure&nbsp;3.&nbsp;Extending the DocBook schema with the MathML schema</b></p><ol type="1"><li>
<p>Download the MathML RELAX NG schema from <a class="link" href="http://yupotan.sppd.ne.jp/relax-ng/mml2.html" target="_top">http://yupotan.sppd.ne.jp/relax-ng/mml2.html</a> and unpack it
somewhere (e.g. into a <code class="filename">mathml</code> subdirectory).</p>
</li><li>
<p>Create a schema customization in compact syntax&#8212;<code class="filename">dbmathml.rnc</code>:</p>
<pre class="programlisting"><span class="rolelabel">r<br>n<br>c</span>namespace html = "http://www.w3.org/1999/xhtml"
namespace mml = "http://www.w3.org/1998/Math/MathML"
namespace db = "http://docbook.org/ns/docbook"

include "/path/to/docbook.rnc" {
  db._any.mml = external "mathml/mathml2.rnc"
  db._any =
    element * - (db:* | html:* | mml:*) {
      (attribute * { text }
       | text
       | db._any)*
    }
}</pre>
<p>Or, alternatively, you can use the XML syntax of RELAX NG&#8212;<code class="filename">dbmathml.rng</code>:</p>
<pre class="programlisting"><span class="rolelabel">r<br>n<br>g</span>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
&lt;grammar xmlns="http://relaxng.org/ns/structure/1.0"&gt;

&lt;include href="/path/to/docbook.rng"&gt;
  &lt;define name="db._any.mml"&gt;
    &lt;externalRef href="mathml/mathml2.rng"/&gt;
  &lt;/define&gt;

  &lt;define name="db._any"&gt;
    &lt;element&gt;
      &lt;anyName&gt;
        &lt;except&gt;
          &lt;nsName ns="http://docbook.org/ns/docbook"/&gt;
          &lt;nsName ns="http://www.w3.org/1999/xhtml"/&gt;
          &lt;nsName ns="http://www.w3.org/1998/Math/MathML"/&gt;
        &lt;/except&gt;
      &lt;/anyName&gt;
      &lt;zeroOrMore&gt;
        &lt;choice&gt;
          &lt;attribute&gt;
            &lt;anyName/&gt;
          &lt;/attribute&gt;
          &lt;text/&gt;
          &lt;ref name="db._any"/&gt;
        &lt;/choice&gt;
      &lt;/zeroOrMore&gt;
    &lt;/element&gt;
  &lt;/define&gt;
&lt;/include&gt;

&lt;/grammar&gt;</pre>
</li><li>
<p>Now use the customized schema (<code class="filename">dbmathml.rnc</code>
or <code class="filename">dbmathml.rng</code>) instead of the original
DocBook schema.</p>
</li></ol></div></td></tr>

<tr class="question"><td align="left" valign="top"><a name="faq-customization-svg"></a><a name="d5e948"></a><p><b>3.2.</b></p></td><td align="left" valign="top"><p>How can I extend the DocBook schema with SVG elements?</p></td></tr>
<tr class="answer"><td align="left" valign="top"></td><td align="left" valign="top"><p>The situation is the same as with MathML support. You can use
elements from the SVG namespace inside the <a href="http://docbook.org/tdg5/en/html/imageobject.html"><code class="sgmltag-element">imageobject</code></a>
element.</p><div class="procedure"><a name="d5e953"></a><p class="title"><b>Procedure&nbsp;4.&nbsp;Extending the DocBook schema with the SVG schema</b></p><ol type="1"><li>
<p>Download the SVG RELAX NG schema from <a class="link" href="http://www.w3.org/Graphics/SVG/1.1/rng/rng.zip" target="_top">http://www.w3.org/Graphics/SVG/1.1/rng/rng.zip</a> and unpack it
somewhere (e.g. into an <code class="filename">svg</code> subdirectory).</p>
</li><li>
<p>Create a schema customization in compact syntax&#8212;<code class="filename">dbsvg.rnc</code>:</p>
<pre class="programlisting"><span class="rolelabel">r<br>n<br>c</span>namespace html = "http://www.w3.org/1999/xhtml"
namespace db = "http://docbook.org/ns/docbook"
namespace svg = "http://www.w3.org/2000/svg"

include "/path/to/docbook.rnc" {
  db._any.svg = external "svg/svg11.rnc"
  db._any =
    element * - (db:* | html:* | svg:*) {
      (attribute * { text }
       | text
       | db._any)*
    }
}</pre>
<p>Or, alternatively, you can use the XML syntax of RELAX NG&#8212;<code class="filename">dbsvg.rng</code>:</p>
<pre class="programlisting"><span class="rolelabel">r<br>n<br>g</span>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
&lt;grammar xmlns="http://relaxng.org/ns/structure/1.0"&gt;

&lt;include href="/path/to/docbook.rng"&gt;
  &lt;define name="db._any.svg"&gt;
    &lt;externalRef href="svg/svg11.rng"/&gt;
  &lt;/define&gt;

  &lt;define name="db._any"&gt;
    &lt;element&gt;
      &lt;anyName&gt;
        &lt;except&gt;
          &lt;nsName ns="http://docbook.org/ns/docbook"/&gt;
          &lt;nsName ns="http://www.w3.org/1999/xhtml"/&gt;
          &lt;nsName ns="http://www.w3.org/2000/svg"/&gt;
        &lt;/except&gt;
      &lt;/anyName&gt;
      &lt;zeroOrMore&gt;
        &lt;choice&gt;
          &lt;attribute&gt;
            &lt;anyName/&gt;
          &lt;/attribute&gt;
          &lt;text/&gt;
          &lt;ref name="db._any"/&gt;
        &lt;/choice&gt;
      &lt;/zeroOrMore&gt;
    &lt;/element&gt;
  &lt;/define&gt;
&lt;/include&gt;

&lt;/grammar&gt;</pre>
</li><li>
<p>Now use the customized schema (<code class="filename">dbsvg.rnc</code>
or <code class="filename">dbsvg.rng</code>) instead of the original
DocBook schema.</p>
</li></ol></div></td></tr>

<tr class="question"><td align="left" valign="top"><a name="faq-customization-mathml-svg"></a><a name="d5e971"></a><p><b>3.3.</b></p></td><td align="left" valign="top"><p>Is it possible to use the previous two customizations for MathML
and SVG together?</p></td></tr>
<tr class="answer"><td align="left" valign="top"></td><td align="left" valign="top"><p>Yes, you can create a special schema customization that combines
both MathML and SVG with the DocBook schema. In compact syntax, the merged
schema is:</p><pre class="programlisting"><span class="rolelabel">r<br>n<br>c</span>namespace html = "http://www.w3.org/1999/xhtml"
namespace mml = "http://www.w3.org/1998/Math/MathML"
namespace db = "http://docbook.org/ns/docbook"
namespace svg = "http://www.w3.org/2000/svg"

include "/path/to/docbook.rnc" {
  db._any.mml = external "mahtml/mathml2.rnc"
  db._any.svg = external "svg/svg11.rnc"
  db._any =
    element * - (db:* | html:* | mml:* | svg:*) {
      (attribute * { text }
       | text
       | db._any)*
    }
}</pre><p>Or alternatively in the full RELAX NG syntax:</p><pre class="programlisting"><span class="rolelabel">r<br>n<br>g</span>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
&lt;grammar xmlns="http://relaxng.org/ns/structure/1.0"&gt;

&lt;include href="/path/to/docbook.rng"&gt;
  &lt;define name="db._any.mml"&gt;
    &lt;externalRef href="mathml/mathml2.rng"/&gt;
  &lt;/define&gt;

  &lt;define name="db._any.svg"&gt;
    &lt;externalRef href="svg/svg11.rng"/&gt;
  &lt;/define&gt;

  &lt;define name="db._any"&gt;
    &lt;element&gt;
      &lt;anyName&gt;
        &lt;except&gt;
          &lt;nsName ns="http://docbook.org/ns/docbook"/&gt;
          &lt;nsName ns="http://www.w3.org/1999/xhtml"/&gt;
          &lt;nsName ns="http://www.w3.org/1998/Math/MathML"/&gt;
          &lt;nsName ns="http://www.w3.org/2000/svg"/&gt;
        &lt;/except&gt;
      &lt;/anyName&gt;
      &lt;zeroOrMore&gt;
        &lt;choice&gt;
          &lt;attribute&gt;
            &lt;anyName/&gt;
          &lt;/attribute&gt;
          &lt;text/&gt;
          &lt;ref name="db._any"/&gt;
        &lt;/choice&gt;
      &lt;/zeroOrMore&gt;
    &lt;/element&gt;
  &lt;/define&gt;
&lt;/include&gt;

&lt;/grammar&gt;</pre></td></tr>

<tr class="question"><td align="left" valign="top"><a name="faq-customization-links"></a><a name="d5e979"></a><p><b>3.4.</b></p></td><td align="left" valign="top"><p>Are there any other examples of schema customization
available?</p></td></tr>
<tr class="answer"><td align="left" valign="top"></td><td align="left" valign="top"><p>Sure. Some of the are listed bellow:</p><div class="itemizedlist"><ul type="disc"><li><p><a class="link" href="http://www.w3.org/TR/xml-i18n-bp/#docbook-plus-its" target="_top">Sample
customization of ITS and DocBook</a></p></li><li><p><a class="link" href="http://wiki.docbook.org/topic/DocbookSchemas" target="_top">Examples on
DocBook WiKi</a></p></li></ul></div></td></tr>
<tr class="qandadiv"><td align="left" valign="top" colspan="2"><h4 class="title"><a name="d5e990"></a>4. Tool specific problems</h4></td></tr><tr class="toc"><td align="left" valign="top" colspan="2"><dl><dt>4.1. <a href="#faq-tools-xmlspy-xmlid">I'm using Altova XMLSpy to validate DocBook V5.0 instances
against the W3C XML Schema (docbook.xsd). XMLSpy
complains about undefined xml:id
attributes?</a></dt></dl></td></tr>
<tr class="question"><td align="left" valign="top"><a name="faq-tools-xmlspy-xmlid"></a><a name="d5e993"></a><p><b>4.1.</b></p></td><td align="left" valign="top"><p>I'm using Altova XMLSpy to validate DocBook V5.0 instances
against the W3C XML Schema (<code class="filename">docbook.xsd</code>). XMLSpy
complains about undefined <code class="sgmltag-attribute">xml:id</code>
attributes?</p></td></tr>
<tr class="answer"><td align="left" valign="top"></td><td align="left" valign="top"><p>XMLSpy always uses its own bundled version of
<code class="filename">xml.xsd</code> which unfortunately doesn't define the <code class="sgmltag-attribute">xml:id</code> attribute. The bundled version of
<code class="filename">xml.xsd</code> is hardwired into the program and cannot
be replaced by a newer version. To solve this problem you must upgrade
to version 2006 SP1.</p></td></tr>
</tbody></table></div>
</div>

<div class="bibliography"><div class="titlepage"><div><div><h2 class="title"><a name="references"></a>Bibliography</h2></div></div></div>

<div class="bibliomixed"><a name="d5e1003"></a><p class="bibliomixed">[<abbr class="abbrev">RNCTUT</abbr>] 

Clark, James &#8211; Cowan, John &#8211; MURATA, Makoto: <span class="title">RELAX NG Compact Syntax Tutorial</span>.
Working Draft, 26 March 2003. OASIS. <span class="bibliomisc"><a class="link" href="http://relaxng.org/compact-tutorial-20030326.html" target="_top">http://relaxng.org/compact-tutorial-20030326.html</a></span>
</p></div>

<div class="bibliomixed"><a name="d5e1008"></a><p class="bibliomixed">[<abbr class="abbrev">NVDLTUT</abbr>] 

N&aacute;levka, Petr:
<span class="title">NVDL Tutorial</span>.
<span class="bibliomisc"><a class="link" href="http://jnvdl.sourceforge.net/tutorial.html" target="_top">http://jnvdl.sourceforge.net/tutorial.html</a></span>
</p></div>

<div class="bibliomixed"><a name="d5e1013"></a><p class="bibliomixed">[<abbr class="abbrev">XMLID</abbr>] 

Marsh, Jonathan &#8211; 
Veillard, Daniel &#8211;
Walsh, Norman: <span class="title">xml:id Version 1.0</span>. W3C Recommendation, 9 September 2005. <span class="bibliomisc"><a class="link" href="http://www.w3.org/TR/xml-id/" target="_top">http://www.w3.org/TR/xml-id/</a></span>
</p></div>

<div class="bibliomixed"><a name="d5e1018"></a><p class="bibliomixed">[<abbr class="abbrev">DB5SPEC</abbr>] 

Norman, Walsh: <span class="title">The DocBook Schema</span>.
Working Draft 5.0a1, OASIS, 29 June 2005.
<span class="bibliomisc"><a class="link" href="http://www.docbook.org/specs/wd-docbook-docbook-5.0a1.html" target="_top">http://www.docbook.org/specs/wd-docbook-docbook-5.0a1.html</a></span>
</p></div>

</div>

<div class="footnotes"><br><hr width="100" align="left"><div class="footnote"><p><sup>[<a name="ftn.d5e711" href="#d5e711" class="para">1</a>] </sup>The examples in this section use
    <code class="filename">docbook.rng</code> as the schema location. If you want
    to create a portable schema customization you should use a standard
    web-accessible location like
    <code class="uri">http://docbook.org/xml/5.0/rng/docbook.rng</code> and
    then use <a class="link" href="http://www.oasis-open.org/committees/download.php/14809/xml-catalogs.html" target="_top">XML
    catalogs</a> to resolve this location to your local copy of the
    schema for improved performance. Unfortunately, at the time of
    this writing not all RELAX NG validators support XML catalogs.</p></div></div></div></body></html>