Short closure return value handling

example.php

<?php

class EventManager {
  private $handlers;
  
  public function onEvent(callable $callback) {
      $this->handlers[] = $callback;
  }
  
  public function invoke(Event $event) {
      foreach ($this->handlers as $handler) {
          $returnValue = $handler($event);
          
          if ($returnValue === false) {
              break;
          }
      }
  }
}

class Cache {
  public function set(string $key, string $value) {
      return true; // returns true if value already existed, otherwise false
  }
}

$eventManager = new EventManager;
$cache = new Cache;

$eventManager->onEvent(fn ($e) => $cache->set($e->getName(), $e->getValue());