parse!

# File activesupport/lib/active_support/duration/iso8601_parser.rb, line 41
      def parse!
        while !finished?
          case mode
          when :start
            if scan(SIGN_MARKER)
              self.sign = (scanner.matched == "-") ? -1 : 1
              self.mode = :sign
            else
              raise_parsing_error
            end

          when :sign
            if scan(DATE_MARKER)
              self.mode = :date
            else
              raise_parsing_error
            end

          when :date
            if scan(TIME_MARKER)
              self.mode = :time
            elsif scan(DATE_COMPONENT)
              parts[DATE_TO_PART[scanner[2]]] = number * sign
            else
              raise_parsing_error
            end

          when :time
            if scan(TIME_COMPONENT)
              parts[TIME_TO_PART[scanner[2]]] = number * sign
            else
              raise_parsing_error
            end

          end
        end

        validate!
        parts
      end