Add support for the Rouge syntax highlighter

By setting the `highlighter` setting to `rouge` you can now easily
highlight your code with it instead of relying on Pygments. However,
Jekyll doesn't depend on Rouge explicitly, you will need to install it
or add it to your Gemfile.

The documentation has been updated accordingly.

History.markdown

@@ -1,12 +1,13 @@
 ## HEAD
 
 ### Major Enhancements
-  * Rename the `pygments` option to `highlighter`
   * Add gem-based plugin whitelist to safe mode (#1657)
   * Replace the commander command line parser with a more robust
     solution for our needs called `mercenary` (#1706)
   * Remove support for Ruby 1.8.x (#1780)
   * Move to jekyll/jekyll from mojombo/jekyll (#1817)
+  * Rename the `pygments` option to `highlighter` (#1859)
+  * Provide support for the Rouge syntax highlighter (#1859)
 
 ### Minor Enhancements
   * Move the EntryFilter class into the Jekyll module to avoid polluting the
@@ -25,7 +26,7 @@
 ### Development Fixes
   * Add a link to the site in the README.md file (#1795)
   * Add in History and site changes from `v1-stable` branch (#1836)
-  * Fix the `highlight` tag feature
+  * Fix the `highlight` tag feature (#1859)
 
 ### Site Enhancements
   * Document Kramdown's GFM parser option (#1791)

features/site_configuration.feature

@@ -98,6 +98,14 @@ Feature: Site configuration
     And I should see "Hello world!" in "_site/index.html"
     And I should see "class=\"highlight\"" in "_site/index.html"
 
+  Scenario: Highlight code with rouge
+    Given I have an "index.html" page that contains "{% highlight ruby %} puts 'Hello world!' {% endhighlight %}"
+    And I have a configuration file with "highlighter" set to "rouge"
+    When I run jekyll
+    Then the _site directory should exist
+    And I should see "Hello world!" in "_site/index.html"
+    And I should see "class=\"highlight\"" in "_site/index.html"
+
   Scenario: Set time and no future dated posts
     Given I have a _layouts directory
     And I have a page layout that contains "Page Layout: {{ site.posts.size }} on {{ site.time | date: "%Y-%m-%d" }}"

jekyll.gemspec

@@ -52,6 +52,7 @@ Gem::Specification.new do |s|
   s.add_development_dependency('activesupport', '~> 3.2.13')
   s.add_development_dependency('jekyll_test_plugin')
   s.add_development_dependency('jekyll_test_plugin_malicious')
+  s.add_development_dependency('rouge', '~> 1.0')
 
   # = MANIFEST =
   s.files = %w[

lib/jekyll/converters/markdown/redcarpet_parser.rb

@@ -5,7 +5,7 @@ module Jekyll
 
         module CommonMethods
           def add_code_tags(code, lang)
-            code = code.sub(/<pre>/, "<pre><code class=\"#{lang} language-#{lang}\" data-lang=\"#{lang}\">")
+            code = code.sub(/<pre(.*?)>/, "<pre><code class=\"#{lang} language-#{lang}\" data-lang=\"#{lang}\">")
             code = code.sub(/<\/pre>/,"</code></pre>")
           end
         end
@@ -22,7 +22,7 @@ module Jekyll
           end
         end
 
-        module WithoutPygments
+        module WithoutHighlighting
           require 'cgi'
 
           include CommonMethods
@@ -37,6 +37,22 @@ module Jekyll
           end
         end
 
+        module WithRouge
+          include CommonMethods
+
+          def block_code(code, lang)
+            require 'rouge'
+
+            lexer = Rouge::Lexer.find_fancy(lang, code) || Rouge::Lexers::PlainText
+            formatter = Rouge::Formatters::HTML.new
+
+            output = "<div class=\"highlight\">"
+            output << add_code_tags(formatter.render(lexer.lex(code)), lang)
+            output << "</div>"
+          end
+        end
+
+
         def initialize(config)
           require 'redcarpet'
           @config = config
@@ -48,9 +64,13 @@ module Jekyll
                           Class.new(Redcarpet::Render::HTML) do
                             include WithPygments
                           end
+                        when 'rouge'
+                          Class.new(Redcarpet::Render::HTML) do
+                            include WithRouge
+                          end
                         else
                           Class.new(Redcarpet::Render::HTML) do
-                            include WithoutPygments
+                            include WithoutHighlighting
                           end
                         end
         rescue LoadError

lib/jekyll/tags/highlight.rb

@@ -44,6 +44,8 @@ eos
         case context.registers[:site].highlighter
         when 'pygments'
           render_pygments(context, super)
+        when 'rouge'
+          render_rouge(context, super)
         else
           render_codehighlighter(context, super)
         end
@@ -65,6 +67,22 @@ eos
         return output
       end
 
+      def render_rouge(context, code)
+        require 'rouge'
+
+        linenos = @options.keys.include?('linenos')
+        lexer = Rouge::Lexer.find_fancy(@lang, code) || Rouge::Lexers::PlainText
+        formatter = Rouge::Formatters::HTML.new(line_numbers: linenos)
+
+        output = context["highlighter_prefix"] || ""
+        output << "<div class=\"highlight\">"
+        output << add_code_tags(formatter.render(lexer.lex(code)), @lang)
+        output << "</div>"
+        output << context["highlighter_suffix"] if context["highlighter_suffix"]
+
+        return output
+      end
+
       def render_codehighlighter(context, code)
         #The div is required because RDiscount blows ass
         <<-HTML

site/_config.yml

@@ -1,4 +1,4 @@
-pygments: true
+highlight: pygments
 relative_permalinks: false
 gauges_id: 503c5af6613f5d0f19000027
 permalink: /news/:year/:month/:day/:title/

site/docs/configuration.md

@@ -288,7 +288,7 @@ encoding:    nil
 future:      true
 show_drafts: nil
 limit_posts: 0
-pygments:    true
+highlighter: pygments
 
 relative_permalinks: true
 
@@ -362,7 +362,7 @@ Jekyll handles two special Redcarpet extensions:
         # ...ruby code
         ```
 
-    With both fenced code blocks and pygments enabled, this will statically highlight the code; without pygments, it will add a `class="LANGUAGE"` attribute to the `<code>` element, which can be used as a hint by various JavaScript code highlighting libraries.
+    With both fenced code blocks and highlighter enabled, this will statically highlight the code; without any syntax highlighter, it will add a `class="LANGUAGE"` attribute to the `<code>` element, which can be used as a hint by various JavaScript code highlighting libraries.
 - `smart` --- This pseudo-extension turns on SmartyPants, which converts straight quotes to curly quotes and runs of hyphens to em (`---`) and en (`--`) dashes.
 
 All other extensions retain their usual names from Redcarpet, and no renderer options aside from `smart` can be specified in Jekyll. [A list of available extensions can be found in the Redcarpet README file.][redcarpet_extensions] Make sure you're looking at the README for the right version of Redcarpet: Jekyll currently uses v2.2.x, and extensions like `footnotes` and `highlight` weren't added until after version 3.0.0. The most commonly used extensions are:
@@ -380,4 +380,4 @@ In addition to the defaults mentioned above, you can also turn on recognition of
 For example, in your `_config.yml`:
 
     kramdown:
-      input: GFM
+      input: GFM

site/docs/installation.md

@@ -66,9 +66,9 @@ Check out [the extras page](../extras/) for more information.
   <h5>ProTip™: Enable Syntax Highlighting</h5>
   <p>
     If you’re the kind of person who is using Jekyll, then chances are you’ll
-    want to enable syntax highlighting using Pygments. You should really
-    <a href="../templates/#code_snippet_highlighting">check out how to do
-    that</a> before you go any further.
+    want to enable syntax highlighting using Pygments or Rouge. You should
+    really <a href="../templates/#code_snippet_highlighting">check out how to
+    do that</a> before you go any further.
   </p>
 </div>
 

site/docs/posts.md

@@ -139,8 +139,8 @@ your `excerpt_separator` to `""`.
 ## Highlighting code snippets
 
 Jekyll also has built-in support for syntax highlighting of code snippets using
-Pygments, and including a code snippet in any post is easy. Just use the
-dedicated Liquid tag as follows:
+either Pygments or [Rouge](https://github.com/jayferd/rouge), and including a
+code snippet in any post is easy. Just use the dedicated Liquid tag as follows:
 
 {% highlight text %}
 {% raw %}{% highlight ruby %}{% endraw %}

site/docs/templates.md

@@ -232,8 +232,14 @@ These parameters are available via Liquid in the include:
 
 Jekyll has built in support for syntax highlighting of [over 100
 languages](http://pygments.org/languages/) thanks to
-[Pygments](http://pygments.org/). To use Pygments, you must have Python installed on your
-system and set `pygments` to `true` in your site's configuration file.
+[Pygments](http://pygments.org/). To use Pygments, you must have Python installed
+on your system and set `highlighter` to `pygments` in your site's configuration
+file.
+
+Alternatively, you can use [Rouge](https://github.com/jayferd/rouge) to highlight
+your code snippets. It doesn't support as many languages as Pygments does but
+it should fit in most cases and it's written in pure Ruby ; you don't need Python
+on your system!
 
 To render a code block with syntax highlighting, surround your code as follows:
 
@@ -249,8 +255,9 @@ end
 
 The argument to the `highlight` tag (`ruby` in the example above) is the
 language identifier. To find the appropriate identifier to use for the language
-you want to highlight, look for the “short name” on the [Lexers
-page](http://pygments.org/docs/lexers/).
+you want to highlight, look for the “short name” on the [Pygments' Lexers
+page](http://pygments.org/docs/lexers/) or the [Rouge
+wiki](https://github.com/jayferd/rouge/wiki/List-of-supported-languages-and-lexers).
 
 #### Line numbers
 
@@ -290,7 +297,7 @@ will generate the correct permalink URL for the post you specify.
 {% endraw %}
 {% endhighlight %}
 
-If you organize your posts in subdirectories, you need to include subdirectory 
+If you organize your posts in subdirectories, you need to include subdirectory
 path to the post:
 
 {% highlight text %}

site/docs/troubleshooting.md

@@ -123,8 +123,8 @@ bug](http://aaronqian.com/articles/2009/04/07/redcloth-ate-my-notextile.html)
 and will hopefully be fixed for 4.2. You can still use 4.1.9, but the
 test suite requires that 4.1.0 be installed. If you use a version of
 RedCloth that does not have the notextile tag, you may notice that
-syntax highlighted blocks from Pygments are not formatted correctly,
-among other things. If you’re seeing this just install 4.1.0.
+syntax highlighted blocks from Pygments or Rouge are not formatted
+correctly, among other things. If you’re seeing this just install 4.1.0.
 
 ### Liquid
 

test/test_redcarpet.rb

@@ -42,6 +42,22 @@ puts "Hello world"
       end
     end
 
+    context "with rouge enabled" do
+      setup do
+        @markdown = Converters::Markdown.new @config.merge({ 'highlighter' => 'rouge' })
+      end
+
+      should "render fenced code blocks with syntax highlighting" do
+        assert_equal "<div class=\"highlight\"><pre><code class=\"ruby language-ruby\" data-lang=\"ruby\"><span class=\"nb\">puts</span> <span class=\"s2\">\"Hello world\"</span>\n</code></pre></div>", @markdown.convert(
+          <<-EOS
+```ruby
+puts "Hello world"
+```
+          EOS
+        ).strip
+      end
+    end
+
     context "without any highlighter" do
       setup do
         @markdown = Converters::Markdown.new @config.merge({ 'highlighter' => nil })