protected function link_nodes(&$node, $is_child)
	{
		$node->parent = $this->parent;
		$this->parent->nodes[] = $node;
		if ($is_child)
		{
			$this->parent->children[] = $node;
		}
	}
protected function link_nodes(&$node, $is_child)
	{
		$node->parent = $this->parent;
		$this->parent->nodes[] = $node;
		if ($is_child)
		{
			$this->parent->children[] = $node;
		}
	}
protected function link_nodes ( & $ node , $ is_child ) { $ node -> parent = $ this -> parent ; $ this -> parent -> nodes [ ] = $ node ; if ( $ is_child ) { $ this -> parent -> children [ ] = $ node ; } }
link node's parent
link node s parent