path.rb

      def call( request )
        capture = {}
        path = extract_path( request )
        capture if @pattern.all? do | want |
          case want
          when true then path = []
          when String then want == path.pop
          when Symbol then capture[ want ] = path.pop
          when Regexp then want === path.pop
          when Hash
            key, value = want.to_a.first
            case value
            when true then
              capture[ key ] = path.reverse
              path = []
            when String, Symbol
              got = path.pop
              capture[ key ] = got ? got : want.to_s
            when Regexp then
              got = path.pop
              capture[ key ] = got if value === got
            end
          end
        end
      end