added support for github style backtick code blocks

.themes/classic/source/_layouts/default.html

@@ -5,7 +5,7 @@
   <nav role=navigation>{% include navigation.html %}</nav>
   <div id="main">
     <div id="content">
-      {{ content | expand_urls: root_url | smart_quotes  }}
+      {{ content | expand_urls: root_url | backtick_codeblock | smart_quotes }}
       {% unless page.sidebar == false %}
         <aside role=sidebar>{% include sidebar.html %}</aside>
       {% endunless %}

plugins/octopress_filters.rb

@@ -1,6 +1,8 @@
 #custom filters for Octopress
+require './plugins/pygments_code'
 
 module OctopressFilters
+  include HighlightCode
   # Used on the blog index to split posts on the <!--more--> marker
   def excerpt(input)
     if input.index(/<!--\s*more\s*-->/i)
@@ -19,6 +21,18 @@ module OctopressFilters
     end
   end
 
+  # for Github style codeblocks eg.
+  # ``` ruby
+  #     code snippet
+  # ```
+  def backtick_codeblock(input)
+    input.gsub /<p>`{3}\s(\w+)<\/p>.+<pre><code>(.+)<\/code><\/pre>.+`{3}<\/p>/m do
+      lang = $1
+      str  = $2.gsub(/^\s{4}/, '').gsub('&lt;','<').gsub('&gt;','>')
+      highlight(str, lang)
+    end
+  end
+
   # Replaces relative urls with full urls
   def expand_urls(input, url='')
     url ||= '/'