From 315f4c9222ef0a6af5362751e897cda1ec1fcb10 Mon Sep 17 00:00:00 2001
From: Kris Brown <kris@kris.me.uk>
Date: Sat, 27 Feb 2010 23:31:54 +0000
Subject: [PATCH] allow converters to be registered through subclassing much
 like railties in rails

---
 lib/jekyll.rb                     |  3 +-
 lib/jekyll/converter.rb           | 50 +++++++++++++++++++++++++++++++
 lib/jekyll/converters/identity.rb |  9 ++----
 lib/jekyll/converters/markdown.rb |  8 +----
 lib/jekyll/converters/textile.rb  |  8 +----
 lib/jekyll/site.rb                |  9 ++----
 6 files changed, 58 insertions(+), 29 deletions(-)
 create mode 100644 lib/jekyll/converter.rb

diff --git a/lib/jekyll.rb b/lib/jekyll.rb
index 7938031d..53a9b84b 100644
--- a/lib/jekyll.rb
+++ b/lib/jekyll.rb
@@ -27,9 +27,10 @@ require 'jekyll/tags/highlight'
 require 'jekyll/tags/include'
 require 'jekyll/albino'
 require 'jekyll/static_file'
+require 'jekyll/converter'
+require 'jekyll/converters/identity'
 require 'jekyll/converters/markdown'
 require 'jekyll/converters/textile'
-require 'jekyll/converters/identity'
 
 module Jekyll
   # Default options. Overriden by values in _config.yml or command-line opts.
diff --git a/lib/jekyll/converter.rb b/lib/jekyll/converter.rb
new file mode 100644
index 00000000..50965be1
--- /dev/null
+++ b/lib/jekyll/converter.rb
@@ -0,0 +1,50 @@
+module Jekyll
+
+  class Converter
+
+    PRIORITIES = { :lowest => -100,
+                   :low => -10,
+                   :normal => 0,
+                   :high => 10,
+                   :highest => 100 }
+
+    class << self
+      def subclasses
+        @subclasses ||= []
+      end
+
+      def inherited(base)
+        subclasses << base
+        subclasses.sort!
+      end
+
+      # priority order of this converter
+      def priority(priority = nil)
+        if priority && PRIORITIES.has_key?(priority)
+          @priority = priority
+        end
+        @priority || :normal
+      end
+
+      # priority order of this converter
+      def content_type(content_type = nil)
+        @content_type = content_type if content_type
+        @content_type || self.name.downcase.gsub(/^.*::/, '').gsub(/converter$/, '')
+      end
+
+      # Spaceship is priority [higher -> lower]
+      #
+      # Returns -1, 0, 1
+      def <=>(other)
+        cmp = PRIORITIES[other.priority] <=> PRIORITIES[self.priority]
+        return cmp
+      end
+    end
+
+    def content_type
+      self.class.content_type
+    end
+
+  end
+
+end
\ No newline at end of file
diff --git a/lib/jekyll/converters/identity.rb b/lib/jekyll/converters/identity.rb
index b21dda7b..ad21bb7b 100644
--- a/lib/jekyll/converters/identity.rb
+++ b/lib/jekyll/converters/identity.rb
@@ -1,15 +1,11 @@
 module Jekyll
-
-  class IdentityConverter
+  class IdentityConverter < Converter
+    priority :lowest
 
     def initialize(config = {})
 
     end
 
-    def content_type
-      nil
-    end
-
     def matches(ext)
       true
     end
@@ -23,5 +19,4 @@ module Jekyll
     end
 
   end
-
 end
diff --git a/lib/jekyll/converters/markdown.rb b/lib/jekyll/converters/markdown.rb
index 3c1aeb50..c7cdbbd5 100644
--- a/lib/jekyll/converters/markdown.rb
+++ b/lib/jekyll/converters/markdown.rb
@@ -1,6 +1,5 @@
 module Jekyll
-
-  class MarkdownConverter
+  class MarkdownConverter < Converter
 
     def initialize(config = {})
       # Set the Markdown interpreter (and Maruku self.config, if necessary)
@@ -52,10 +51,6 @@ module Jekyll
       end
     end
 
-    def content_type
-      "markdown"
-    end
-
     def matches(ext)
       ext =~ /(markdown|mkdn?|md)/i
     end
@@ -65,5 +60,4 @@ module Jekyll
     end
 
   end
-
 end
diff --git a/lib/jekyll/converters/textile.rb b/lib/jekyll/converters/textile.rb
index 50d28276..79eb5476 100644
--- a/lib/jekyll/converters/textile.rb
+++ b/lib/jekyll/converters/textile.rb
@@ -1,15 +1,10 @@
 module Jekyll
-
-  class TextileConverter
+  class TextileConverter < Converter
 
     def initialize(config = {})
 
     end
 
-    def content_type
-      "textile"
-    end
-
     def matches(ext)
       ext =~ /textile/i
     end
@@ -23,5 +18,4 @@ module Jekyll
     end
 
   end
-
 end
diff --git a/lib/jekyll/site.rb b/lib/jekyll/site.rb
index 17243296..df7bc612 100644
--- a/lib/jekyll/site.rb
+++ b/lib/jekyll/site.rb
@@ -19,7 +19,6 @@ module Jekyll
       self.permalink_style = config['permalink'].to_sym
       self.exclude         = config['exclude'] || []
       self.future          = config['future']
-      self.converters      = []
 
       self.reset
       self.setup
@@ -39,11 +38,7 @@ module Jekyll
       # Check to see if LSI is enabled.
       require 'classifier' if self.lsi
 
-      # converters
-      converters << Jekyll::MarkdownConverter.new(self.config)
-      converters << Jekyll::TextileConverter.new(self.config)
-      converters << Jekyll::IdentityConverter.new(self.config)
-
+      self.converters = Jekyll::Converter.subclasses.collect { |c| c.new(self.config) }
     end
 
     # Do the actual work of processing the site and generating the
@@ -135,7 +130,7 @@ module Jekyll
       end
     end
 
-    # Reads the directories and finds posts, pages and static files that will 
+    # Reads the directories and finds posts, pages and static files that will
     # become part of the valid site according to the rules in +filter_entries+.
     #   The +dir+ String is a relative path used to call this method
     #            recursively as it descends through directories