Online PHP editor | output for su8MU

<?php class Event { private $eventName; function __construct($eventName){ $this->eventName = $eventName; } public function name() { return $this->eventName; } } class QueueManager { private $registeredHandlers = array(); public function addEventListener($eventName, $handler) { if (!isset($this->registeredHandlers[$eventName]) || !is_array($this->registeredHandlers[$eventName])) $this->registeredHandlers[$eventName] = array(); $this->registeredHandlers[$eventName][] = $handler; } public function dispatch($event, &...$args) { $eventName = $event->name(); if (!$this->registeredHandlers[$eventName]) return; foreach ($this->registeredHandlers[$eventName] as $handler) call_user_func_array($handler, $args); } } $qm = new QueueManager(); $qm->addEventListener('click', function(){echo 'ok1';}); //something like this working $qm->addEventListener('click', function(){echo 'ok2';}); $qm->addEventListener('adding', function(&$x){$x = 5;}); //something like this not working $qm->addEventListener('adding', function($x){$x++;}); $qm->addEventListener('adding', function($x){echo $x;}); $clickEvent = new Event('click'); $qm->dispatch($clickEvent); $addingEvent = new Event('adding'); $value; $qm->dispatch($addingEvent, $value);