How to write documentation for &l4l; ?
[write_doc]
Overview
The &l4l; documentation is composed of XML files which are processed with XSL stylesheets to produce XHTML files.
There these XML files are writen in a syntax similar to the HTML syntax, plus some helpers.
The whole documentation is generated through a make system, which uses xmllint to check the validy of the xml files and xsltproc to process them and generate the XHTML pages. These two programs are mandatory
The syntax
A doc page looks like this :
<?xml version="1.0" encoding="UTF-8" standalone="no" ?>
<?xml-stylesheet type="text/xsl" href="../xsl/doc.xsl"?>
<!DOCTYPE doc SYSTEM "../dtd/doc.dtd">
<doc>
<head>
<title>How to write documentation for &l4l; ?</title>
<ref>write_doc</ref>
<links>
<link ref="http://lcd4linux.sf.net"/>
</links>
</head>
<body>
...
</body>
</doc>
The three first lines are the preambule of the file, don't touch them.
The root of the document is <doc>, it's the equivalent of <html>.
Then, there's a <head> node, containing the information about the page. See later for the childs.
The core of the doc is the <body> node, like in HTML, containing the content.
The <head>
The head contains some information about the document :
<title> is the title of the document, which will be displayed as a <h1>
<ref> is a unique reference for the document, which is assumed to be the same as in references.xml (we'll discuss later about this file)
<links> is the section responsible of the "See Alo" box, containing links to other help pages, or to urls. It can contain several <link> elements, whose syntax is explained in the next part.
There may be other elements, but we'll only use these ones for now.
The helpers
You can use a lot of helpers in the body :
<link> is a helper to create links. It is used with one of these two arguments :
- <link ref="xxx"/> will create a link to the documentation page associated with this reference (defined in references.xml)
- <link url="http://..."/> will create a link to the url
Note that if you don't provide a text, the text of the link will be the label of the reference or the url. You can specify a text writing <link url="http://...">TEXT</link>
As this is XML, you must close all the tags you open, or use self-closing tags for empty ones :
For example, you have to write <br/> but not <br>.
<cmd> Opens a box with write text on black background, used to indicate something's happening in a console (compilation, logs, ...). The text is in "pre" mode, so spaces and newlines are kept, no need of or <br/>, But beware of < and > (you must replace them with < and >)
xav:~$ echo "An example of <cmd> box"
An example of <cmd> box
xav:~$
<conf> works like <cmd> but with black text on grey background, to print lcd4linux.conf examples.
Widget Lightning {
class 'icon'
speed 100
visible cpu('busy', 500)-50
bitmap {
row1 '...***'
row2 '..***.'
row3 '.***..'
row4 '.****.'
row5 '..**..'
row6 '.**...'
row7 '**....'
row8 '*.....'
}
}
<note> is to display a box with a small icon, to point out a detail, or an advice
To dry a wet cat, don't put it in a microwave ;)
<warn> works like <note> but with a red exclamation mark and a red border, to display warnings. In general, use a note for a detail or an advice and warn to point configuration problems, hardware hazards, or other happy things ;)
We're not responsible for damages caused to your microwave if you don't read the above note !
<index> is a cool thing. It displays the list of pages of a specified class. It's used to display indexes. For example <index class="drivers"/> will display a list of all pages about drivers. If there's no class specified, it'll parse the list of pages of the "lcd4linux" class.
<new> is in the DTD, but is not yet implemented :/
You can use any other XHTML-valid tag. The most used should be : <br/> <h2> <h3> <li> <b> <i> <tt> ...
references.xml
There's a file in data/ called references.xml. It isn't processed directly, but is used to parse links and indexes. It's syntax is quite straightforward, so I won't explain it.
You must add a new entry in it for each page you write so that other pages can have links to it and index it.
A null <class/> attribute corresponds to the lcd4linux class. It's not a bug, it's a feature, used to make links (the lcd4linux class is in the root of the documentation)
The compilation system
The documentation is compiled with a Makefile build system. There's a toplevel Makefile which calls the apropriate targets in each subdirs which contains xml files (for the moment, lcd4linux, drivers and plugins). In these subdirs, the Makefile is a link to Makefile.generic.
To compile the documentation, just type make at the toplevel, and look in the HTML folder. Type make help for help ;)
Two programs are mandatory to build the documentation :
- xmllint from libxml2 is used to validate the xml pages to be processed. It's in the debian package libxml2
- xsltproc from libxslt processes the xml files to generate the html pages. It's in the libxslt tarballs or in the xsltproc debian package