Compile less filter

hamlit.gemspec

@@ -26,9 +26,11 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency 'bundler', '~> 1.10'
   spec.add_development_dependency 'coffee-script'
   spec.add_development_dependency 'faml', '>= 0.3.3'
+  spec.add_development_dependency 'less'
   spec.add_development_dependency 'minitest-reporters', '~> 1.1'
   spec.add_development_dependency 'rails', '>= 4.0.0'
   spec.add_development_dependency 'rake', '~> 10.0'
+  spec.add_development_dependency 'therubyracer'
   spec.add_development_dependency 'thor', '~> 0.19'
   spec.add_development_dependency 'unindent'
 end

lib/hamlit/filters.rb

@@ -3,6 +3,7 @@ require 'hamlit/filters/tilt_base'
 require 'hamlit/filters/coffee'
 require 'hamlit/filters/css'
 require 'hamlit/filters/escaped'
+require 'hamlit/filters/less'
 require 'hamlit/filters/javascript'
 require 'hamlit/filters/plain'
 require 'hamlit/filters/preserve'
@@ -26,6 +27,7 @@ module Hamlit
     register :coffeescript, Coffee
     register :css,          Css
     register :escaped,      Escaped
+    register :less,         Less
     register :javascript,   Javascript
     register :plain,        Plain
     register :preserve,     Preserve

lib/hamlit/filters/less.rb

@@ -0,0 +1,32 @@
+require 'tilt'
+
+module Hamlit
+  class Filters
+    class Less < TiltBase
+      def compile(node)
+        if Haml::Util.contains_interpolation?(node.value[:text])
+          return runtime_compile(node)
+        end
+
+        temple = [:multi]
+        temple << [:static, "<style>\n".freeze]
+        temple << [:static, TiltBase.render('less', node.value[:text])]
+        temple << [:static, "</style>".freeze]
+        temple
+      end
+
+      private
+
+      def runtime_compile(node)
+        source = Haml::Util.unescape_interpolation(node.value[:text])
+        code = "::Hamlit::Filters::TiltBase.render('less', #{source})"
+
+        temple = [:multi]
+        temple << [:static, "<style>\n".freeze]
+        temple << [:dynamic, code]
+        temple << [:static, "</style>".freeze]
+        temple
+      end
+    end
+  end
+end

test/hamlit/filters/less_test.rb

@@ -3,7 +3,6 @@ describe Hamlit::Filters do
 
   describe '#compile' do
     it 'renders less filter' do
-      skip
       assert_render(<<-HAML, <<-HTML, compatible_only: :haml, error_with: :faml)
         :less
           .users_controller {
@@ -23,7 +22,6 @@ describe Hamlit::Filters do
     end
 
     it 'parses string interpolation' do
-      skip
       assert_render(<<-'HAML', <<-HTML, compatible_only: :haml, error_with: :faml)
         :less
           .foo {