<?xml version="1.0" encoding="utf-8"?>
<!--
   Copyright (c) 2002 Douglas Gregor <doug.gregor -at- gmail.com>
  
   Distributed under the Boost Software License, Version 1.0.
   (See accompanying file LICENSE_1_0.txt or copy at
   http://www.boost.org/LICENSE_1_0.txt)
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<!DOCTYPE chapter PUBLIC "-//Boost//DTD BoostBook XML V1.0//EN"
  "http://www.boost.org/tools/boostbook/dtd/boostbook.dtd">
<chapter xmlns:xi="http://www.w3.org/2001/XInclude" id="boostbook.documenting"
         last-revision="$Date$">
  <title>Documenting libraries</title>
    
  <para>BoostBook is an extension to <ulink
  url="http://www.docbook.org">DocBook</ulink>, an XML format for
  representing documentation. BoostBook inherits much of its
  functionality and many elements from DocBook that are not
  redocumented here. When writing BoostBook documentation, please
  refer also to <ulink
  url="http://docbook.org/tdg/en/index.html">DocBook: The Definitive
  Guide</ulink>.</para>

  <section id="boostbook.defining">
    <title>Defining a BoostBook library</title>
    
    <para>BoostBook library documentation is contained entirely within
    a &lt;library&gt; XML element. To create a skeletal library, we
    need to create a new XML document (call it <code>any.xml</code>)
    that contains basic information about the library. The following
    <link linkend="boostbook.documenting.skeletal">BoostBook XML
    example</link> describes basic information about the <ulink
    url="http://www.boost.org/libs/any/index.html">Boost.Any</ulink>
    library:</para>

    <example id="boostbook.documenting.skeletal">
      <title>A Skeletal BoostBook Library</title>
      <programlisting>
&lt;?xml version="1.0" encoding="utf-8"?&gt;
&lt;!DOCTYPE library PUBLIC "-//Boost//DTD BoostBook XML V1.0//EN"
  "http://www.boost.org/tools/boostbook/dtd/boostbook.dtd"&gt;
&lt;library name="Any" dirname="any" xmlns:xi="http://www.w3.org/2001/XInclude"
  id="any" last-revision="$Date$"&gt;
  &lt;libraryinfo&gt;
    &lt;author&gt;
      &lt;firstname&gt;Kevlin&lt;/firstname&gt;
      &lt;surname&gt;Henney&lt;/surname&gt;
    &lt;/author&gt;
    &lt;librarypurpose&gt;
      Safe, generic container for single values of different value types
    &lt;/librarypurpose&gt; 
    &lt;librarycategory name="category:data-structures"/&gt;
  &lt;/libraryinfo&gt;
&lt;/library&gt;
</programlisting>
    </example>

    <para>The first three lines identify this document as a BoostBook
    <ulink url="http://www.w3.org/XML/">XML</ulink> document. The
    DOCTYPE line states that the document conforms to the BoostBook
    DTD, and that the top-level element is a BoostBook
    &lt;library&gt;.</para>

    <para>The &lt;library&gt; element actually describes the aspects
    of BoostBook library documentation. The attributes for the
    &lt;library&gt; element are:</para>

    <variablelist>
      <title>Attributes for the &lt;library&gt; element</title>
      <varlistentry>
        <term><code>name</code></term>
        <listitem>
          <simpara>The full name of the library, e.g., "Any"</simpara>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><code>dirname</code></term>
        <listitem>
          <simpara>The name of the directory, relative to
            <code>boost/libs</code>, in which the library
            resides. This name may be a relative path, such as
            <code>math/octonion</code>, using "/" for the directory
            separator.</simpara>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><code>id</code></term>
        <listitem>
          <simpara>A short, unique name for the library. For libraries
          with simple directory names (e.g., ones that do not contain
          a "/"), this should be the same as the
          <code>dirname</code>. This <code>id</code> will be used to
          identify libraries and, for HTML output, will be used as the
          base name for the HTML file in which the library's
          documentation resides, so it should use only lowercase
          alphanumeric characters and underscores.</simpara>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><code>last-revision</code></term>
        <listitem>
          <simpara>Always set to <code>$Date$</code>, which is
          expanded by CVS to include the date and time that the file
          was last modified.</simpara>
        </listitem>
      </varlistentry>
    </variablelist>

    <para>Inside the &lt;library&gt; element we have the
    &lt;libraryinfo&gt; element, which gives information about the
    library itself. It contains the author's name (there may be more
    than one &lt;author&gt; element), followed by the purpose of the
    library and the list of categorizations. The
    &lt;librarypurpose&gt; element should always contain a very short
    (single sentence) description of the library's purpose, and should
    <emphasis>not</emphasis> terminate with a period.</para>

    <para>The list of categories is specified by a set of
    &lt;librarycategory&gt; elements. Each &lt;librarycategory&gt;
    element has a <code>name</code> element that identifies one of the
    categories. The actual list of categories is in the file
    <filename>doc/src/boost.xml</filename>.
    </para>

    <para>At this point, we can apply the BoostBook XSL stylesheets to
    <code>any.xml</code> (to DocBook) followed by a DocBook XSL
    stylesheet to generate HTML output, as described in <xref
    linkend="boostbook.getting.started"/>.</para>
  </section>

  <section>
    <title>From HTML to BoostBook</title>

    <para>Most library authors are comfortable with writing HTML
    documentation. Writing <ulink
    url="http://www.docbook.org">DocBook</ulink> documentation (and,
    by extension, BoostBook documentation) is quite similar to writing
    HTML, except that BoostBook uses different element names from HTML
    (see <xref linkend="html.to.boostbook"/>) and BoostBook XML is a
    much more rigid format than HTML.</para>

    <para>One of the easiest ways to convert HTML documentation into
    BoostBook documentation is to use <ulink
    url="http://tidy.sourceforge.net/">HTML Tidy</ulink> to transform
    your HTML into valid XHTML, which will make sure that all elements
    are properly closed, then apply the transformations in <xref
    linkend="html.to.boostbook"/> to the body of the XHTML
    document. The following command uses HTML Tidy to transform HTML
    into valid XHTML:</para>
    
    <programlisting>
  tidy -asxhtml input.html &gt; output.xhtml</programlisting>

    <para>When converting documentation from HTML to BoostBook, note
    that some redundant information that has to be manually maintained
    in HTML is automatically generated in BoostBook: for instance, the
    library categorizations, purpose, and author list described in
    <xref linkend="boostbook.defining"/> are used both in the
    documentation for the library and to build alphabetical and
    categorized lists of known libraries; similarly, tables of
    contents are built automatically from the titles of sections in
    the BoostBook document.</para>

    <table id="html.to.boostbook">
      <title>Converting HTML elements to BoostBook</title>
      <tgroup cols="2" align="left">
        <thead>
          <row>
            <entry>HTML</entry>
            <entry>BoostBook</entry>
          </row>
        </thead>
        <tbody>
          <row>
            <entry><simpara>&lt;h1&gt;, &lt;h2&gt;, etc.</simpara></entry>
            <entry>
<simpara>&lt;section&gt;, &lt;title&gt;; See <xref
linkend="boostbook.sectioning"/></simpara>
</entry>
          </row>
          <row>
            <entry><simpara>&lt;i&gt;, &lt;em&gt;</simpara></entry>
            <entry><simpara>&lt;emphasis&gt;</simpara></entry>
          </row>
          <row>
            <entry><simpara>&lt;b&gt;</simpara></entry>
            <entry><simpara>&lt;emphasis role="bold"&gt;</simpara></entry>
          </row>
          <row>
            <entry><simpara>&lt;ol&gt;</simpara></entry>
            <entry><simpara>&lt;orderedlist&gt;</simpara></entry>
          </row>
          <row>
            <entry><simpara>&lt;ul&gt;</simpara></entry>
            <entry><simpara>&lt;itemizedlist&gt;</simpara></entry>
          </row>
          <row>
            <entry><simpara>&lt;li&gt;</simpara></entry>
            <entry><simpara>&lt;listitem&gt;</simpara></entry>
          </row>
          <row>
            <entry><simpara>&lt;pre&gt;</simpara></entry>
            <entry><simpara>&lt;programlisting&gt;</simpara></entry>
          </row>
          <row>
            <entry><simpara>&lt;code&gt;</simpara></entry>
            <entry><simpara>&lt;computeroutput&gt;,&lt;code&gt;</simpara></entry>
          </row>
          <row>
            <entry><simpara>&lt;p&gt;</simpara></entry>
            <entry><simpara>&lt;para&gt;, &lt;simpara&gt;</simpara></entry>
          </row>
          <row>
            <entry><simpara>&lt;a&gt;</simpara></entry>
            <entry>
<simpara>&lt;xref&gt;, &lt;link&gt;, &lt;ulink&gt;;, See <xref
linkend="boostbook.linking"/></simpara></entry>
          </row>
          <row>
            <entry><simpara>&lt;table&gt;, &lt;tr&gt;, &lt;th&gt;, &lt;td&gt;</simpara></entry>
            <entry><simpara>&lt;table&gt;, &lt;informaltable&gt;, &lt;tgroup&gt;, &lt;thead&gt;, &lt;tfoot&gt;, &lt;tbody&gt;, &lt;row&gt;, &lt;entry&gt;, &lt;entrytbl&gt;; BoostBook tables are equivalent to DocBook tables, for which there is a good <ulink url="http://opensource.bureau-cornavin.com/crash-course/en/tables.html">tutorial here</ulink></simpara></entry>
          </row>
        </tbody>
      </tgroup>
    </table>
  </section>

  <section id="boostbook.sectioning">
    <title>Sectioning in BoostBook</title>
    <para>"Sectioning" refers to organization of a document into separate sections, each with a title, some text, and possibly subsections. Each section is described in BoostBook via a &lt;section&gt; element. An introduction section may look like this:</para>
    <programlisting>
&lt;section id="any.intro"&gt;
  &lt;title&gt;Introduction&lt;/title&gt;
 
  &lt;para&gt;Introduction to a library...&lt;/para&gt;

  &lt;section&gt;
    &lt;title&gt;A Subsection&lt;/title&gt;
    &lt;para&gt;Subsection information...&lt;/para&gt;
  &lt;/section&gt;
&lt;/section&gt;
</programlisting>
    <para>The &lt;section&gt; element contains all information that
    should logically be grouped within that section. The title of the
    section is placed within the &lt;title&gt; element, and any
    paragraphs, programs, lists, tables, or subsections can occur
    within the section. The <code>id</code> attribute of the
    &lt;section&gt; element gives a unique ID to each section, so that
    it may later be identified for linking. It is suggested that all
    IDs start with the short name of a library followed by a period,
    so that IDs do not conflict between libraries.</para>
  </section>
</chapter>