code: func parseString(s string) (string, string, error) {
  
  	if s[0] != '\'' && s[0] != '"' {
  		panic("string should start with open quote. calling code should have asserted this")
  	}
  
  	match := s[0]
  
  	s = s[1:]
  
  	var i int
  	for i < len(s) && s[i] != match {
  		i++
  	}
  
  	if i == len(s) {
  		return "", "", ErrMissingQuote
  
  	}
  
  	return s[:i], s[i+1:], nil
  }
docs: // caller must assure s starts with a single or double quote