Allow custom markdown processors

[parkr]

Requires that the custom markdown processor be a constant defined within Jekyll::Converters::Markdown. Example:

If I want to add theoretical, biblical, mystical HTML Pipeline to my site as a custom processor, I define a converter plugin with #initialize and #convert defined, perhaps something like this:

require 'jekyll'
require 'html/pipeline'

class Jekyll::Converters::Markdown::HTMLPipeline
  def initialize(config)
    # You can do other fancy things with the config here,
    # but for now we'll just save it for later.
    @config = config
  end

  def convert(content)
    HTML::Pipeline.new(content).to_html(@config["html_pipeline_options"])
  end
end

Then in my _config.yml, I define the class I just created as my markdown:

markdown: HTMLPipeline

Run your Jekyll build, et voilà!

If you're writing your own markdown processor and are not sure where to start despite my above example, take a look at the KramdownParser class, a living, breathing, sweating markdown parser.

---

Props to @envygeeks and @gjtorikian. Let's make it happen!

• Code
• Tests
• Documentation

Supersedes #1213, #1871. Closes #1871.

[parkr]

Hello docs:

[gjtorikian]

😂

With this (embiggened) emphasis on plugins, maybe it's appropriate to discuss how users can discover these features, outside of constantly updating the links on jekyllrb.com? /cc @benbalter @mattr-

[parkr]

Would be happy to talk over some sort of search functionality. I have a horribly botched idea here: https://github.com/jekyll/plugins.jekyllrb.com

We'd expose plugins via JSON (name, author, keywords, what have you) and could conduct a search based on a keyword or something, so I could run jekyll plugin search redirect to search for all plugins with the "redirect" keyword or that have "redirect" in the name.

[gjtorikian]

Not a bad idea. We could piggyback it onto the GitHub search API for fun and profit.

[parkr]

@gjtorikian Piggyback into GitHub Search API? How do you mean?

[envygeeks]

That's not a bad idea, especially if you add a gem addon or something that queries the websites json and then does a gem install of "jekyll-plugin-name" something like jekyll plugin search tags -> jekyll plugin install my-tags -> gem install jekyll-plugin-my-tags or just throw it into the _plugins/ folder or add a --path command so they can designate a destination for non-gem installs.

[envygeeks]

@parkr: https://api.github.com/search/code?q=addClass+in:file+language:js+repo:jquery/jquery