Merge pull request #325 from jch/syntax-highlight-filter/unused-code-and-docs

Improves syntax highlight filter

Author: gjtorikian

lib/html/pipeline/syntax_highlight_filter.rb

@@ -4,8 +4,15 @@
 
 module HTML
   class Pipeline
-    # HTML Filter that syntax highlights code blocks wrapped
-    # in <pre lang="...">.
+    # HTML Filter that syntax highlights text inside code blocks.
+    #
+    # Context options:
+    #
+    #   :highlight => String represents the language to pick lexer. Defaults to empty string.
+    #   :scope => String represents the class attribute adds to pre element after.
+    #             Defaults to "highlight highlight-css" if highlights a css code block.
+    #
+    # This filter does not write any additional information to the context hash.
     class SyntaxHighlightFilter < Filter
       def initialize(*args)
         super(*args)
@@ -23,11 +30,8 @@ def call
           next if html.nil?
 
           node.inner_html = html
-          klass = node['class']
-          scope = context[:scope] || "highlight-#{lang}"
-          klass = [klass, scope].compact.join ' '
-
-          node['class'] = klass
+          scope = context.fetch(:scope) { 'highlight' }
+          node['class'] = "#{scope} #{scope}-#{lang}"
         end
         doc
       end

test/html/pipeline/syntax_highlight_filter_test.rb

@@ -11,6 +11,7 @@ def test_highlight_default
       '<pre>hello</pre>', highlight: 'coffeescript'
 
     doc = filter.call
+    assert !doc.css('.highlight').empty?
     assert !doc.css('.highlight-coffeescript').empty?
   end