segment_for

# File actionpack/lib/action_controller/routing/builder.rb, line 34
      def segment_for(string)
        segment =
          case string
            when  /\A\.(:format)?\// 
              OptionalFormatSegment.new
            when /\A:(\w+)/
              key = $1.to_sym
              key == :controller ? ControllerSegment.new(key) : DynamicSegment.new(key)
            when /\A\*(\w+)/
              PathSegment.new($1.to_sym, :optional => true)
            when /\A\?(.*?)\?/
              StaticSegment.new($1, :optional => true)
            when nonseparator_regexp
              StaticSegment.new($1)
            when separator_regexp
              DividerSegment.new($&, :optional => optional_separators.include?($&))
          end
        [segment, $~.post_match]
      end