php_parser.php
public function free()
    {
        unset($this->tags);
        unset($this->page);
        unset($this->private_content_tags);
        $this->open_forms             = array();
        $this->complete_forms         = array();
        $this->frameset               = false;
        $this->loading_frames         = array();
        $this->frameset_nesting_level = 0;
        $this->left_over_labels       = array();
    }
public function free()
    {
        unset($this->tags);
        unset($this->page);
        unset($this->private_content_tags);
        $this->open_forms             = array();
        $this->complete_forms         = array();
        $this->frameset               = false;
        $this->loading_frames         = array();
        $this->frameset_nesting_level = 0;
        $this->left_over_labels       = array();
    }
Frees up any references so as to allow the PHP garbage collection from unset() to work.