Add an explicit method to retrieve supported languages.

lib/coderay.rb

@@ -279,6 +279,20 @@ def get_scanner_options options
       options.fetch :scanner_options, {}
     end
 
+    # Provide a list of supported code languages.
+    #
+    # Returns a hash of symbols.
+    def supported_languages(include_aliases=true, include_internals=false)
+      languages = CodeRay::Scanners.list
+      if include_aliases == true
+        languages += CodeRay::Scanners.plugin_hash.keys.map(&:to_sym)
+      end
+      if include_internals == false
+        languages -= %w(debug default raydebug scanner).map(&:to_sym)
+      end
+      return languages
+    end
+
   end
 
 end

test/functional/basic.rb

@@ -155,6 +155,40 @@ def test_list_of_scanners
     assert CodeRay::Scanners.list.include?(:text)
   end
 
+  def test_supported_languages_should_return_array_of_symbols
+    assert_kind_of(Array, CodeRay.supported_languages)
+    assert_kind_of(Symbol, CodeRay.supported_languages.first)
+  end
+
+  def test_supported_languages_should_include_languages
+    assert CodeRay.supported_languages.include?(:ruby)
+  end
+
+  def test_supported_languages_without_arguments_should_include_aliases_and_exclude_internals
+    assert CodeRay.supported_languages.include?(:javascript)
+    assert !CodeRay.supported_languages.include?(:debug)
+  end
+
+  def test_supported_languages_with_arguments_should_include_aliases_and_exclude_internals
+    assert CodeRay.supported_languages(true, false).include?(:javascript)
+    assert !CodeRay.supported_languages(true, false).include?(:debug)
+  end
+
+  def test_supported_languages_with_arguments_should_exclude_aliases_and_include_internals
+    assert !CodeRay.supported_languages(false, true).include?(:javascript)
+    assert CodeRay.supported_languages(false, true).include?(:debug)
+  end
+
+  def test_supported_languages_with_arguments_should_include_aliases_and_internals
+    assert CodeRay.supported_languages(true, true).include?(:javascript)
+    assert CodeRay.supported_languages(true, true).include?(:debug)
+  end
+
+  def test_supported_languages_with_arguments_should_exclude_aliases_and_internals
+    assert !CodeRay.supported_languages(false, false).include?(:javascript)
+    assert !CodeRay.supported_languages(false, false).include?(:debug)
+  end
+
   def test_token_kinds
     assert_kind_of Hash, CodeRay::TokenKinds
     for kind, css_class in CodeRay::TokenKinds