Online PHP editor | output for Ov24F

<?php class Observer { static protected $events = array(); static public function register($callable, $event){ if (!isset(self::$events[$event])) { self::$events[$event] = array(); } self::$events[$event][] = $callable; } static public function notify($event, $params = array()) { if (isset(self::$events[$event])) { foreach (self::$events[$event] AS $callable){ call_user_func_array($callable, $params); } } } } function print_meta($p1, $p2) { echo $p1 . ' ' . $p2 . PHP_EOL; } function multiply_meta($p1, $p2) { echo $p1 * $p2 . PHP_EOL; } function add_meta($p1, $p2) { echo $p1 + $p2 . PHP_EOL; } Observer::register('print_meta', 'event1'); Observer::register('multiply_meta', 'event1'); Observer::register('print_meta', 'event2'); Observer::register('add_meta', 'event2'); Observer::register('multiply_meta', 'event3'); Observer::register('add_meta', 'event3'); echo "Notifying of event 1" . PHP_EOL; Observer::notify('event1', array(1, 2)); echo "Notifying of event 2" . PHP_EOL; Observer::notify('event2', array(3, 4)); echo "Notifying of event 3" . PHP_EOL; Observer::notify('event3', array(5, 6));