Boost C++ Libraries

BoostBook library documentation is contained entirely within a <library> XML element. To create a skeletal library, we need to create a new XML document (call it any.xml) that contains basic information about the library. The following BoostBook XML example describes basic information about the Boost.Any library:

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE library PUBLIC "-//Boost//DTD BoostBook XML V1.0//EN"
  "http://www.boost.org/tools/boostbook/dtd/boostbook.dtd">
<library name="Any" dirname="any" xmlns:xi="http://www.w3.org/2001/XInclude"
  id="any" last-revision="$Date: 2008-07-12 20:30:45 +0100 (Sat, 12 Jul 2008) $">
  <libraryinfo>
    <author>
      <firstname>Kevlin</firstname>
      <surname>Henney</surname>
    </author>
    <librarypurpose>
      Safe, generic container for single values of different value types
    </librarypurpose> 
    <librarycategory name="category:data-structures"/>
  </libraryinfo>
</library>

The first three lines identify this document as a BoostBook XML document. The DOCTYPE line states that the document conforms to the BoostBook DTD, and that the top-level element is a BoostBook <library>.

The <library> element actually describes the aspects of BoostBook library documentation. The attributes for the <library> element are:

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

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

At this point, we can apply the BoostBook XSL stylesheets to any.xml (to DocBook) followed by a DocBook XSL stylesheet to generate HTML output, as described in the section called “Getting Started”.

Most library authors are comfortable with writing HTML documentation. Writing DocBook documentation (and, by extension, BoostBook documentation) is quite similar to writing HTML, except that BoostBook uses different element names from HTML (see Table 36.2, “Converting HTML elements to BoostBook”) and BoostBook XML is a much more rigid format than HTML.

One of the easiest ways to convert HTML documentation into BoostBook documentation is to use HTML Tidy to transform your HTML into valid XHTML, which will make sure that all elements are properly closed, then apply the transformations in Table 36.2, “Converting HTML elements to BoostBook” to the body of the XHTML document. The following command uses HTML Tidy to transform HTML into valid XHTML:

  tidy -asxhtml input.html > output.xhtml

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 the section called “Defining a BoostBook library” 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.

"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 <section> element. An introduction section may look like this:

<section id="any.intro">
  <title>Introduction</title>
 
  <para>Introduction to a library...</para>

  <section>
    <title>A Subsection</title>
    <para>Subsection information...</para>
  </section>
</section>

The <section> element contains all information that should logically be grouped within that section. The title of the section is placed within the <title> element, and any paragraphs, programs, lists, tables, or subsections can occur within the section. The id attribute of the <section> 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.