/**
* (non-PHPdoc)
*
* @see library/POData/QueryProcessor/Expressions/Expressions.AbstractExpression::free()
*
* @return void
*/
public function free()
{
if (!is_null($this->parent)) {
$this->parent->free();
unset($this->parent);
}
if (!is_null($this->child)) {
$this->child->free();
unset($this->child);
}
}