code: func (s *Scanner) emitSimple(t tokenType, v string) *Token {
  	token := &Token{t, v, s.row, s.col}
  	s.col += len(v)
  	s.pos += len(v)
  	return token
  }
docs: // emitSimple returns a Token for the string v and updates the scanner
  // position in a simplified manner.
  //
  // The string is known to have only ASCII characters and to not have a newline.