# File lib/action_view/helpers/url_helper.rb, line 92
      def url_for(options = {})
        options ||= {}
        url = case options
        when String
          options
        when Hash
          options = options.symbolize_keys.reverse_merge!(:only_path => options[:host].nil?)
          super
        when :back
          controller.request.env["HTTP_REFERER"] || 'javascript:history.back()'
        else
          polymorphic_path(options)
        end

        url
      end