Documentation Guidelines

Privoxy Developer Manual
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# 3. Documentation Guidelines

All formal documents are maintained in Docbook SGML and located in the `doc/source/*` directory. You will need Docbook, the Docbook DTD's and the Docbook modular stylesheets (or comparable alternatives), and either jade or openjade (recommended) installed in order to build docs from source. Currently there is user-manual, FAQ, and, of course this, the developer-manual in this format. The README, AUTHORS, INSTALL, privoxy.8 (man page), and config files are also now maintained as Docbook SGML. These files, when built, in the top-level source directory are generated files! Also, the Privoxy `index.html` (and a variation on this file, `privoxy-index.html`, meant for inclusion with doc packages), are maintained as SGML as well. DO NOT edit these directly. Edit the SGML source, or contact someone involved in the documentation.

`config` requires some special handling. The reason it is maintained this way is so that the extensive comments in the file mirror those in user-manual. But the conversion process requires going from SGML to HTML to text to special formatting required for the embedded comments. Some of this does not survive so well. Especially some of the examples that are longer than 80 characters.

Other, less formal documents (e.g. `LICENSE`) are maintained as plain text files in the top-level source directory.

Packagers are encouraged to include this documentation. For those without the ability to build the docs locally, text versions of each are kept in Git. HTML versions are also being kept in Git under `doc/webserver/*`.

Formal documents are built with the Makefile targets of `make dok`. The build process uses the document SGML sources in `doc/source/*/*` to update all text files in `doc/text/` and to update all HTML documents in `doc/webserver/`.

Documentation writers should please make sure documents build successfully before committing to Git, if possible.

How do you update the webserver (i.e. the pages on privoxy.org)?

1. First, build the docs by running `make dok dok-tidy`.

2. Run `make webserver` which copies all files from `doc/webserver` to the sourceforge webserver via ssh.

Finished docs should be occasionally submitted to Git (`doc/webserver/*/*.html`) so that those without the ability to build them locally, have access to them if needed. This is especially important just prior to a new release! Please do this after the `$VERSION` and other release specific data in `configure.in` has been updated (this is done just prior to a new release).

## 3.1. Quickstart to Docbook and SGML

If you are not familiar with SGML, it is a markup language similar to HTML. Actually, not a mark up language per se, but a language used to define markup languages. In fact, HTML is an SGML application. Both will use "tags" to format text and other content. SGML tags can be much more varied, and flexible, but do much of the same kinds of things. The tags, or "elements", are definable in SGML. There is no set "standards". Since we are using Docbook, our tags are those that are defined by Docbook. Much of how the finish document is rendered is determined by the "stylesheets". The stylesheets determine how each tag gets translated to HTML, or other formats.

Tags in Docbook SGML need to be always "closed". If not, you will likely generate errors. Example: `<title>My Title</title>`. They are also case-insensitive, but we strongly suggest using all lower case. This keeps compatibility with [Docbook] XML.

Our documents use "sections" for the most part. Sections will be processed into HTML headers (e.g. `h1` for `sect1`). The Docbook stylesheets will use these to also generate the Table of Contents for each doc. Our TOC's are set to a depth of three. Meaning `sect1`, `sect2`, and `sect3` will have TOC entries, but `sect4` will not. Each section requires a `<title>` element, and at least one `<para>`. There is a limit of five section levels in Docbook, but generally three should be sufficient for our purposes.

Some common elements that you likely will use:

<para></para>, paragraph delimiter. Most text needs to be within paragraph elements (there are some exceptions).
<emphasis></emphasis>, the stylesheets make this italics.
<filename></filename>, files and directories.
<command></command>, command examples.
<literallayout></literallayout>, like `<pre>`, more or less.
<itemizedlist></itemizedlist>, list with bullets.
<listitem></listitem>, member of the above.
<screen></screen>, screen output, implies `<literallayout>`.
<ulink url="example.com"></ulink>, like HTML `<a>` tag.
<quote></quote>, for, doh, quoting text.

Look at any of the existing docs for examples of all these and more.

You might also find " Writing Documentation Using DocBook - A Crash Course" useful.

## 3.2. Privoxy Documentation Style

It will be easier if everyone follows a similar writing style. This just makes it easier to read what someone else has written if it is all done in a similar fashion.

Here it is:

- All tags should be lower case.

- Tags delimiting a block of text (even small blocks) should be on their own line. Like:

  <para>
  Some text goes here.
  </para>

  Tags marking individual words, or few words, should be in-line:

  Just to <emphasis>emphasize</emphasis>, some text goes here.

- Tags should be nested and step indented for block text like: (except in-line tags)

  <para>
  <itemizedlist>
  <para>
  <listitem>
  Some text goes here in our list example.
  </listitem>
  </para>
  </itemizedlist>
  </para>

  This makes it easier to find the text amongst the tags ;-)

- Use white space to separate logical divisions within a document, like between sections. Running everything together consistently makes it harder to read and work on.

- Do not hesitate to make comments. Comments can either use the <comment> element, or the <!-- --> style comment familiar from HTML. (Note in Docbook v4.x <comment> is replaced by <remark>.)

- We have an international audience. Refrain from slang, or English idiosyncrasies (too many to list :). Humor also does not translate well sometimes.

- Try to keep overall line lengths in source files to 80 characters or less for obvious reasons. This is not always possible, with lengthy URLs for instance.

- Our documents are available in differing formats. Right now, they are just plain text and/or HTML, but others are always a future possibility. Be careful with URLs (<ulink>), and avoid this mistake:

  My favorite site is <ulink url="http://example.com">here</ulink>.

  This will render as "My favorite site is here", which is not real helpful in a text doc. Better like this:

  My favorite site is <ulink url="http://example.com">example.com</ulink>.

- All documents should be spell checked occasionally. aspell can check SGML with the `-H` option. (ispell I think too.)

## 3.3. Privoxy Custom Entities

Privoxy documentation is using a number of customized "entities" to facilitate documentation maintenance.

We are using a set of "boilerplate" files with generic text, that is used by multiple docs. This way we can write something once, and use it repeatedly without having to re-write the same content over and over again. If editing such a file, keep in mind that it should be generic. That is the purpose; so it can be used in varying contexts without additional modifications.

We are also using what Docbook calls "internal entities". These are like variables in programming. Well, sort of. For instance, we have the `p-version` entity that contains the current Privoxy version string. You are strongly encouraged to use these where possible. Some of these obviously require re-setting with each release (done by the Makefile). A sampling of custom entities are listed below. See any of the main docs for examples.

- Re- "boilerplate" text entities are defined like:

  `<!entity supported SYSTEM "supported.sgml">`

  In this example, the contents of the file, `supported.sgml` is available for inclusion anywhere in the doc. To make this happen, just reference the now defined entity: `&supported;` (starts with an ampersand and ends with a semi-colon), and the contents will be dumped into the finished doc at that point.

- Commonly used "internal entities":

  p-version: the Privoxy version string, e.g. "4.0.0".
  p-status: the project status, either "alpha", "beta", or "stable".
  p-not-stable: use to conditionally include text in "not stable" releases (e.g. "beta").
  p-stable: just the opposite.
  p-text: this doc is only generated as text.

There are others in various places that are defined for a specific purpose. Read the source!

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