Parkdown --- Ruby Markdown library

Parkdown is a Ruby extension library around my fork of John MacFarlane's fast implementation of Markdown in C. This extension library is a fork of Ryan Tomayko's rpeg-markdown library. The main difference between Ryan's library and Parkdown is the underlying parser. Ryan's library uses an outdated version of John MacFarlane's peg-markdown, while Parkdown uses the parser generated from my heavily extended Markdown grammar.

>> require 'markdown'
>> puts Markdown.new('Hello, world.').to_html
<p>Hello, world.</p>

>> puts Markdown.new('_Hello World!_', :smart, :filter_html).to_html
<p><em>Hello World!</em></p>

>> puts Markdown.new('_Hello World!_').to_latex
\emph{Hello World!}

>> puts Markdown.new('_Hello World!_').to_groff_mm
.P
\fIHello world!\fR

Parkdown comes with the following non-standard extensions that are not found in the libraries its originally based on:

• HTML5 video embedding: %[caption](file-url.ogv alternative.mp4)
• HTML5 audio embedding: ~[title](file-url.ogg alternative.mp3)
• autolink: turns plain URLs (not wrapped in angled brackets) into clickable links
• strike-through: I owe you ~~ten~~ twenty coins.
• image filtering: renders images as regular links
• hard wrap: translate simple line breaks into HTML line breaks
• code blocks: wrap a block in ~~~ to render it as a code block
• hashtags: wraps any term starting with # in <span rel="hashtag">...</span>
• usernames: wraps any name starting with @ in <span rel="username">...</span>
• spoilers: a block prefixed with ?> will be wrapped in a <div class="spoilers">. Use CSS and JS to hide and show the block as needed.

The hard work of rendering some plain text syntax to HTML/LaTeX/ODF/etc. is done by the parser that is generated from the grammar in peg-markdown. To implement custom extensions, fork peg-markdown and extend the grammar. Then update the peg-markdown submodule in your fork of parkdown and expose the extension in the Ruby library. Use the rake task rake gather to build the parser from the grammar in the peg-markdown/ directory and collect the files in ext/. Then build the extension with rake build.

Patches are happily accepted via pull requests or email.

This library requires a recent version of glib2. All modern GNU userland systems should be fine.

Install from GEM:

$ sudo gem install parkdown

The peg-markdown sources are licensed under the GPL and Parkdown adopts this license (just as the original rpeg-markdown did). See the file LICENSE included with this distribution for more information.