[Haml] Add a :css filter.

doc-src/HAML_CHANGELOG.md

@@ -29,6 +29,11 @@ Haml and `html2haml` now produce more descriptive errors
 when given a template with invalid byte sequences for that template's encoding,
 including the line number and the offending character.
 
+### `:css` Filter
+
+Haml now supports a {file:HAML_REFERENCE.md#css-filter `:css` filter}
+that surrounds the filtered text with `<style>` and CDATA tags.
+
 ### `html2haml` Improvements
 
 * Ruby blocks within ERB are now supported.

doc-src/HAML_REFERENCE.md

@@ -1081,6 +1081,11 @@ when you don't want lines starting with `.` or `-` to be parsed.
 Surrounds the filtered text with `<script>` and CDATA tags.
 Useful for including inline Javascript.
 
+{#css-filter}
+### `:css`
+Surrounds the filtered text with `<style>` and CDATA tags.
+Useful for including inline CSS.
+
 {#cdata-filter}
 ### `:cdata`
 Surrounds the filtered text with CDATA tags.

lib/haml/filters.rb

@@ -200,6 +200,23 @@ END
       end
     end
 
+    # Surrounds the filtered text with `<style>` and CDATA tags.
+    # Useful for including inline CSS.
+    module Css
+      include Base
+
+      # @see Base#render_with_options
+      def render_with_options(text, options)
+        <<END
+<style type=#{options[:attr_wrapper]}text/css#{options[:attr_wrapper]}>
+  /*<![CDATA[*/
+    #{text.rstrip.gsub("\n", "\n    ")}
+  /*]]>*/
+</style>
+END
+      end
+    end
+
     # Surrounds the filtered text with CDATA tags.
     module Cdata
       include Base

test/haml/engine_test.rb

@@ -909,6 +909,21 @@ END
 END
   end
 
+  def test_css_filter
+    assert_equal(<<CSS, render(<<SASS))
+<style type='text/css'>
+  /*<![CDATA[*/
+    #foo {
+      bar: baz; }
+  /*]]>*/
+</style>
+CSS
+:css
+  #foo {
+    bar: baz; }
+SASS
+  end
+
   def test_local_assigns_dont_modify_class
     assert_equal("bar\n", render("= foo", :locals => {:foo => 'bar'}))
     assert_equal(nil, defined?(foo))