public function free($deep = false, $position = 0)
{
// WARNING! Use this method with care. It resets the scanner!
$this->_lexer->resetPosition($position);
// Deep = true cleans peek and also any previously defined errors
if ($deep) {
$this->_lexer->resetPeek();
}
$this->_lexer->token = null;
$this->_lexer->lookahead = null;
}