code: func (t tokenset) String() string {
  	// concatenate the tokens into a single string
  	_rtn := ""
  	for _, _t := range []*Token(t) {
  		_rtn = _rtn + _t.Token()
  	}
  	return _rtn
  }
docs: // String() returns a concatenated string of all runes represented by the
  // list of tokens.