ArsDigita created a good documentation ground for us to build upon. Some sections of the documentation, however, lack details and examples; others are simply nonexistant. Our goal is to give OpenACS a superb documentation, so that users, developers and administrators of OpenACS installations can enjoy the system.

OpenACS is a powerful system, with incredible possibilities and applications, but with this power comes some complexity and a learning curve that will only be atenuated by good documentation. This is what we are after.

The documentation for OpenACS is written using DocBook XML. The reasons why we are using DocBook are explained in more details in the next section. A few more reasons why we are using Docbook XML instead of Docbook SGML:

In order to separate content and presentation, all OpenACS documentation will be marked up to conform to the DocBook XML DTD This enables us to publish in a variety of formats and relieves each contributor of the burden of presentation, freeing him to focus on content and sharing knowledge.

Theoretically any strict DTD would have been sufficient - we could even write our own. But DocBook has been around for a while (since the early 90's), it's well-tested, it's complete, it's designed for technical documentation and best of all, it's open-source. A growing community surrounds DocBook (has mailing lists) and a number of free and commercial tools are available for editing and publishing DocBook documents.

This primer walks you through the basics, and should cover the needs for 95 percent of the documentation we produce. However, you're always welcome to check out DocBook's list of elements and use more exotic features in your documents. The list is made up of SGML-elements but basically the same elements are valid in the XML DTD as long as you remember to:

You are going to need the following to work with the OpenACS Docbook XML documentation:

After you have the tools mentioned above, you need to define a title for your document. Then start thinking about the possible sections and subsections you will have in your document. Make sure you coordinate with the OpenACS Gatekeepers to make sure you're not writing something that someone else is already writing. Also, if you desire to use the OpenACS CVS repository, please e-mail the gatekeeper in charge of documentation.

You can look at some templates for documents (in Docbook XML) in the sources for acs-core-docs, especially the Detailed Design Documentation Template and the System/Application Requirements Template.

The documentation for each package will make up a little "book" that is structured like this - examples are emphasized:

    book                        : Docs for one package - templating
     |
     +--chapter                 : One section - for developers
         |
---------+------------------------------------------------------
         |
         +--sect1               : Single document - requirements
             |
             +--sect2           : Sections - functional requirements
                 |
                 +--sect3       : Subsections - Programmer's API
                     |
                    ...         : ...
    

The actual content is split up into documents that start at a sect1-level. These are then tied together in a top-level document that contains all the information above the line. This will be explained in more detail in a later document, and we will provide a set of templates for documenting an entire package.

For now you can take a look at the sources of these DocBook documents to get an idea of how they are tied together.

Given that your job starts at the sect1-level, all your documents should open with a <sect1>-tag and end with the corresponding </sect1>.

You need to feed every <sect1> two attributes. The first attribute, id, is standard and can be used with all elements. It comes in very handy when interlinking between documents (more about this when talking about links in the section called “Links”). The value of id has to be unique throughout the book you're making since the id's in your sect1's will turn into filenames when the book is parsed into HTML.

The other attribute is xreflabel. The value of this is the text that will appear as the link when referring to this sect1.

Right after the opening tag you put the title of the document - this is usually the same as xreflabel-attribute. E.g. the top level of the document you're reading right now looks like this:

<sect1 id="docbook-primer" xreflabel="aD DocBook Primer">
  <title>aD DocBook Primer</title>

...

</sect1>

Inside this container your document will be split up into <sect2>'s, each with the same requirements - id and xreflabel attributes, and a <title>-tag inside. Actually, the xreflabel is never required in sections, but it makes linking to that section a lot easier.

When it comes to naming your sect2's and below, prefix them with some abbreviation of the id in the sect1 such as requirements-overview.

For displaying a snippet of code, a filename or anything else you just want to appear as a part of a sentence, we will use the tag <computeroutput>. This takes the place of the HTML-tag <code>

For bigger chunks of code such as SQL-blocks, the tag <programlisting> is used. Just wrap your code block in it; mono-spacing, indents and all that stuff is taken care of automatically.

Linking falls into two different categories: inside the book you're making and outside:

NOTE: Currently this section currently only takes HTML-output into consideration - not a printed version

Another Note: Also, it's still not a 100 percent sure that this is how we are going to do it, so if you want to start converting your documents right away, start out with the ones without graphics ;)

To insert a graphic we use the elements <mediaobject>, <imageobject>, and <imagedata>. The news is that you have to provide two versions of all your graphics - one for the Web (probably a GIF or a JPEG) and one for print (EPS). Finally you should provide a brief description wrapped in <textobject> - in HTML this will be the ALT text.

<mediaobject>
  <imageobject>
    <imagedata fileref="../images/rp-flow.gif" format="GIF" align="center"/>
  </imageobject>
  <imageobject>
    <imagedata fileref="../images/rp-flow.eps" format="EPS" align="center"/>
  </imageobject>
  <textobject>
    <phrase>This is an image of the flow in the Request Processor</phrase>
  </textobject>
</mediaobject>

Put your graphics in a separate directory ("images") and link to them only with relative paths.

Here's how you make the DocBook equivalent of the three usual HTML-lists:

DocBook supports several types of tables, but in most cases, the <informaltable> is enough:

<informaltable frame="all">
  <tgroup cols="3">
    <tbody>

      <row>
        <entry>a1</entry>
        <entry>b1</entry>
        <entry>c1</entry>
      </row>

      <row>
        <entry>a2</entry>
        <entry>b2</entry>
        <entry>c2</entry>
      </row>

      <row>
        <entry>a3</entry>
        <entry>b3</entry>
        <entry>c3</entry>
      </row>

    </tbody>
  </tgroup>
</informaltable>

With our current XSL-style-sheet, the output of the markup above will be a simple HTML-table:

If you want cells to span more than one row or column, it gets a bit more complicated - check out <table> for an example.

Our documentation uses two flavors of emphasis - italics and bold type. DocBook uses one - <emphasis>.

The <emphasis> tag defaults to italics when parsed. If you're looking for emphasizing with bold type, use <emphasis role="strong">.

Marking up index-words may not have any importance for the HTML-output, but in order to make it easier to make a nice print-version of the documentation, you should mark up words in your documents that you would like to see show up in an index one day.

Use <indexterm>, <primary> and <secondary> for this. See these links for an explanation.

Once you have the Docbook Tools installed, you can convert your xml documents to HTML or other formats.

With the DocBook XSL stylesheets, generation of multiple files is controlled by the stylesheet. If you want to generate a single file, you call one stylesheet. If you want to generate multiple files, you call a different stylesheet.

To generate a single HTML file from your DocBook XML file, use the command:

bash$  xsltproc -o outputfilename.xml /usr/share/sgml/docbook/stylesheet/xsl/nwalsh/html/html.xsl filename.xml

To generate a set of linked HTML pages, with a separate page for each <chapter>, <sect1> or <appendix> tag, use the following command:

bash$  xsltproc /usr/share/sgml/docbook/stylesheet/xsl/nwalsh/html/chunk.xsl filename.xml

You could also look at the acs-core-docs Makefile for examples of how these documents are generated.