Online PHP editor | refs for TvcXf

<?php class Super { protected $child; function setChild(Child $child){ $this->child = $child; if($child->getSuper() !== $this) $child->setSuper($this); } } class Child { protected $super; function setSuper(Super $super){ $this->super = $super; $this->super->addChild($this); } function getSuper(){ return $this->super; } } $super = new Super; $child = new Child; $super->setChild($child); var_dump($super); $super = new Super; $child = new Child; $child->setSuper($super); var_dump($super);