code: func (fp *formatParser) freshCode(i int, r rune) error {
  	fp.start = i
  	fp.code = (*formatParser).codeCode
  	fp.next = (*formatParser).codeNext
  	fp.end = (*formatParser).codeEnd
  	return nil
  }
docs: // Called when the parser is not currently parsing a static string and the next
  // character in the format string is a code '%'.