code: func (s *Scanner) Tokenize() (cs chan string) {
  	cs = make(chan string)
  	go func() {
  		defer close(cs)
  		for r := s.Scan(); r != EOF; r = s.Scan() {
  			cs <- s.TokenText()
  		}
  		cs <- s.TokenText()
  	}()
  	return
  }
docs: // Tokenize returns a chan of tokens found in scanner until exhaustion