$weakReferences=false on the child node, the parent node can be accessed through * $node->getAttribute('parent'). * * With $weakReferences=true the attribute name is "weak_parent" instead. */ final class ParentConnectingVisitor extends NodeVisitorAbstract { /** * @var Node[] */ private array $stack = []; private bool $weakReferences; public function __construct(bool $weakReferences = false) { $this->weakReferences = $weakReferences; } public function beforeTraverse(array $nodes) { $this->stack = []; } public function enterNode(Node $node) { if (!empty($this->stack)) { $parent = $this->stack[count($this->stack) - 1]; if ($this->weakReferences) { $node->setAttribute('weak_parent', \WeakReference::create($parent)); } else { $node->setAttribute('parent', $parent); } } $this->stack[] = $node; } public function leaveNode(Node $node) { array_pop($this->stack); } }