protected function isOutputAssignment()
	{
		return ($this->tokens[$this->i    ] === [T_VARIABLE,        '$this']
		     && $this->tokens[$this->i + 1] === [T_OBJECT_OPERATOR, '->']
		     && $this->tokens[$this->i + 2] === [T_STRING,          'out']
		     && $this->tokens[$this->i + 3] === [T_CONCAT_EQUAL,    '.=']);
	}