# File lib/yard/generators/full_doc_generator.rb, line 85
      def markup_for(filename)
        case File.extname(filename).downcase
        when /^\.(?:mdown|markdown|mkdn|markdn|md)$/
          :markdown
        when ".textile"
          :textile
        when /^\.html?$/
          if format == :html
            nil # no markup, use raw data
          else
            # TODO implement some html->plaintext markup
            :rdoc
          end
        else
          if @contents =~ /\A#!(\S+)\s*$/ # Shebang support
            markup = $1
            @contents.gsub!(/\A.+?\r?\n/, '')
            markup.to_sym
          else
            :rdoc
          end
        end
      end