look_for_directives_in

# File lib/rdoc/parsers/parse_rb.rb, line 2309
    def look_for_directives_in(context, comment)

      preprocess = SM::PreProcess.new(@input_file_name,
                                      @options.rdoc_include)

      preprocess.handle(comment) do |directive, param|
        case directive
        when "stopdoc"
          context.stop_doc
          ""
        when "startdoc"
          context.start_doc
          context.force_documentation = true
          ""

        when "enddoc"
          #context.done_documenting = true
          #""
          throw :enddoc

        when "main"
          options = Options.instance
          options.main_page = param
          ""

        when "title"
          options = Options.instance
          options.title = param
          ""

        when "section"
          context.set_current_section(param, comment)
          comment.replace("") # 1.8 doesn't support #clear
          break 
        else
          warn "Unrecognized directive '#{directive}'"
          break
        end
      end

      remove_private_comments(comment)
    end