Sketch for a Tilt/Markdown extension that makes it a little easier to add structure to markdown after its rendered.

doc.erb.bd

# How to tie your shoes

<%= toc.each do |id, text| %>
* [<%= text %>](#<%= id %>)
<% end %>

## Unlace them

Gotta make sure its untied before you tie it!

## Eat a piece of pizza

This is all I know how to do.

## Tie the shoes

I really don't know how to break this down.

## Celebrate!

Yay! Lets party!

throwdown.rb

ThrowDown.new do
  extension '.braddown', '.bd'
  # Before this code gets hit, the base markdown renders. Next we scan
  # through the doc's H tags and drop an id into each of them based on the
  # H tag text.
  transform do
    doc.find('h1, h2, h3, h4, h5, h6').each { |h| h[:id] = h.text.downcase.gsub(' ', '_') }
  end
  # Now we're in a spot where we can extract this H tag into some useful data that
  # we might want to access from inside the view itself (like a TOC) or from outside 
  # in something like a pager (maybe we break apart by H1 tags).
  extract :toc do
    doc.find('h1, h2, h3, h4, h5, h6').map{ |h| [ h[:id], h.text ]  }
  end
  # This is just for fun... but really its useful... running MD images through
  # sprockets. This is how its done folks! (Not sure if Sprockets.image_path works,
  # but you get the idea)
  transform do
    doc.find('img[src]').each { |img| img[:src] = Sprockets.image_path(img[:src]) }
  end
end