readme.mdpp

Markdown Preprocessor (MarkdownPP)
==================================

The Markdown Preprocessor is a Python module designed to add extended features
on top of the excellent Markdown syntax defined by John Gruber.  These additions
are mainly focused on creating larger technical documents without needing to use
something as heavy and syntactically complex as Docbook.

MarkdownPP uses a set of selectable modules to apply a series of transforms to
the original document, with the end goal of generating a new Markdown document
that contains sections or features that would be laborious to generate or
maintain by hand.

Documents designed to be preprocessed by MarkdownPP should try to follow the
convention of naming files with a .mdpp extension, so that MarkdownPP can
generate a document with the same name, but with the standard .md extension.
As an example, this document in raw format is named "readme.mdpp", and the
generated document from MarkdownPP is named "readme.md" so that GitHub can find
and process that document when viewing the repository.

[![Build Status](https://travis-ci.org/jreese/markdown-pp.svg?branch=master)](https://travis-ci.org/jreese/markdown-pp)

!TOC

Installation and Usage
----------------------

Currently, you'll need to download the source code from [GitHub][repo] or clone
the repository, and the run the installation script manually.

    pip install MarkdownPP

There are two components to the project: a Python module, `MarkdownPP`, and a
Python script that acts as a simple command line interface to the module,
`markdown-pp`.

Assuming you have a file named `foo.mdpp`, you can generate the preprocessed
file `foo.md` by running the following command:

    $ markdown-pp foo.mdpp -o foo.md

If you do not specify an output file name, the results will be printed to
stdout, enabling them to be piped to another command.

By default, all available modules are enabled. You can specify a list of
modules to exclude:

    $ markdown-pp foo.mdpp -o foo.md -e latexrender,youtubembed

To see usage instructions, including a list of enabled modules, supply the
-h or --help arguments:

    $ markdown-pp --help


Modules
--------

### Includes

In order to facilitate large documentation projects, MarkdownPP has an Include
module that will replace a line of the form `!INCLUDE "path/to/filename"` with
the contents of that file, recursively including other files as needed.

File `foo.mdpp`:

	Hello

File `bar.mdpp`:

	World!

File `index.mdpp`:

	!INCLUDE "foo.mdpp"
	!INCLUDE "bar.mdpp"

Compiling `index.mdpp` with the Include module will produce the following:

	Hello
	World!

### IncludeURLs

Facilitates the inclusion of remote files, such as files kept in a subversion
or GitHub repository. Like Include, the IncludeURL module can replace a line of
the form `!INCLUDEURL "http://your.domain/path/to/filename"` with the contents
returned from that url, recursively including additional remote urls as needed.

IncludeURL runs immediately after the Include module finishes executing. This
means that is it possible to include local files that then require remote files,
but impossible parse !INCLUDE statements found in remote files. This is prevent
ambiguity as to where the file would be located.

Remote file `http://your.domain/foo.mdpp`:

    Hello

Remote file `http://your.domain/bar.mdpp`:

    Remote World!

Local file `index.mdpp`:

    !INCLUDEURL "http://your.domain/foo.mdpp"
    !INCLUDEURL "http://your.domain/bar.mdpp"

Compiling `index.mdpp` with the IncludeURL module will produce the following:

    Hello
    Remote World!

### Table of Contents

The biggest feature provided by MarkdownPP is the generation of a table of
contents for a document, with each item linked to the appropriate section of the
markup.  The table is inserted into the document wherever the preprocessor finds
`!TOC` at the beginning of a line.  Named `<a>` tags are inserted above each
Markdown header, and the headings are numbered hierarchically based on the
heading tag that Markdown would generate.

### Reference

Similarly, MarkdownPP can generate a list of references that follow Markdown's
alternate link syntax, eg `[name]: <url> "Title"`.  A list of links will be
inserted wherever the preprocessor finds a line beginning with `!REF`.  The
generated reference list follows the same alternate linking method to ensure
consistency in your document, but the link need not be referenced anywhere in
the document to be included in the list.

### LaTeX Rendering

Lines and blocks of lines beginning and ending with $ are rendered as LaTeX,
using [QuickLaTeX](http://www.holoborodko.com/pavel/quicklatex/).

For example,

	$\displaystyle \int x^2 = \frac{x^3}{3} + C$

becomes

$\displaystyle \int x^2 = \frac{x^3}{3} + C$

### YouTube Embeds

As GitHub-flavored Markdown does not allow embed tags, each line of the form
`!VIDEO "[youtube url]"` is converted into a screenshot that links to the video,
roughly simulating the look of an embedded video player.

For example,

    !VIDEO "http://www.youtube.com/embed/7aEYoP5-duY"

becomes

!VIDEO "http://www.youtube.com/embed/7aEYoP5-duY"


Examples
--------

Example file.mdpp:

	# Document Title

	!TOC

	## Header 1
	### Header 1.a
	## Header 2

	!REF

	[github]: http://github.com "GitHub"

The preprocessor would generate the following Markdown-ready document file.md:

	# Document Title

	1\. [Header 1](#header1)
	1.1\. [Header 1.a](#header1a)
	2\. [Header 2](#header2)

	<a name="header1"></a>
	## Header 1
	<a name="header1a"></a>
	### Header 1.a
	<a name="header2"></a>
	## Header 2

	*	[GitHub][github]

	[github]: http://github.com "GitHub"


Support
-------

If you find any problems with MarkdownPP, or have any feature requests, please
report them to [GitHub][repo], and I will respond when possible.  Code
contributions are *always* welcome, and ideas for new modules, or additions to
existing modules, are also appreciated.


References
----------

!REF

[repo]: http://github.com/jreese/markdown-pp "Markdown Preprocessor on GitHub"