# File lib/action_controller/mime_responds.rb, line 102
      def respond_to(*types, &block)
        raise ArgumentError, "respond_to takes either types or a block, never both" unless types.any? ^ block
        block ||= lambda { |responder| types.each { |type| responder.send(type) } }
        responder = Responder.new(self)
        block.call(responder)
        responder.respond
      end