Using CodeRay -and- Syntax with RedCloth

syntax_for_redcloth.rb

#
#  Using CodeRay -and- Syntax with RedCloth
#
#  Setup both gems in config/environment.rb
#    config.gem "syntax",  :version => '1.0.0'
#    config.gem "coderay", :version => '0.8.312'
#
#  Then drop this in config/initializers
#
#  Now you can:
#
#    For Syntax:
#      bc[s_ruby].       => Syntax for Ruby
#      @[s_yaml]text@    => Syntax for YAML
#
#    For CodeRay:
#      Using style= tags w/ the default style
#        bc[cs_ruby].      => CodeRay for Ruby
#        @[cs_yaml]text@   => CodeRay for YAML
#
#      Using class= tags w/ your stylesheet
#        bc[cc_ruby].      => CodeRay for Ruby
#        @[cc_yaml]text@   => CodeRay for YAML
#
module SyntaxHighlighter
  module ForRedCloth
    def self.install
      RedCloth::Formatters::HTML.module_eval do
        def unescape(html)
          replacements = {
            '&'  => '&',
            '"' => '"',
            '>'   => '>',
            '&lt;'   => '<',
          }
          html.gsub(/&(?:amp|quot|[gl]t);/) { |entity| replacements[entity] }
        end
        undef_method :code, :bc_open, :bc_close, :escape_pre
        def code(opts)
          opts[:block] = true
          if opts[:lang] =~ /^(s|cc|cs)_(\w+)/
            @in_bc ||= nil
            code, lang = $~[1], $~[2]
            if code == 's'
              syntax_lexer(lang, opts)
            else
              css = (code == 'cc') ? {:css => :class} : {}
              coderay_lexer(lang, css, opts)
            end
          else
            "<code#{pba(opts)}>#{opts[:text]}</code>"
          end
        end

        def syntax_lexer(lang, opts)
          single_line = "<span class=\"syntax_inline_#{lang}\">%s</span>"
          multi_line  = "<div class=\"syntax_multiline_#{lang}\">%s</div>"
          wrap_in = @in_bc ? multi_line : single_line
          opts[:text] = unescape(opts[:text]) unless @in_bc
          highlighted_code = wrap_in % Syntax::Convertors::HTML.for_syntax(lang).convert(opts[:text])
          highlighted_code.gsub!(/<pre>|<\/pre>/, '') unless @in_bc
          highlighted_code
        end

        def coderay_lexer(lang, css, opts)
          format = @in_bc ? :div : :span
          highlighted_code = CodeRay.encode opts[:text], lang, format, {:stream => true}.merge(css)
          highlighted_code.sub!(/\A<(span|div)/) { |m| m + pba(@in_bc || opts) }
          highlighted_code = unescape(highlighted_code) unless @in_bc
          highlighted_code
        end

        def bc_open(opts)
          opts[:block] = true
          @in_bc = opts
          opts[:lang] ? '' : "<pre#{pba(opts)}>"
        end
        def bc_close(opts)
          opts = @in_bc
          @in_bc = nil
          opts[:lang] ? '' : "</pre>\n"
        end

        def escape_pre(text)
          if @in_bc ||= nil
            text
          else
            html_esc(text, :html_escape_preformatted)
          end
        end
      end
    end
  end
end
SyntaxHighlighter::ForRedCloth.install