Online PHP editor | output for iYADo

<?php /* Challenge 1: Modify Test::$secret before it's output. Rules:: 1. No use of Reflection API / runkit extension 2. No stopping execution before Test::run() 3. No Exceptions or PHP errors / warnings notices allowed Hints: 1. Caesar 2. Magic methods 3. Requires a new feature of PHP 5.4 */ class Test { private $secret = 'Nyy lbhe Onfr ner orybat gb hf.'; private $callback; final public function run() { call_user_func($this->callback); return $this->secret . PHP_EOL; } public function __set($k, $v) { $key = $v[($v[$v])]; // $v is some kind of weird array $value = $v(); // and a callback! $this->{$key} = $value; } } $test = new Test; // start editing here class A implements ArrayAccess { private $callCount = 0; public function __invoke(){ return function(){ echo "A".$this->secret."B";die; }; } public function offsetSet($offset, $value) {} public function offsetExists($offset) { return true; } public function offsetUnset($offset) {} public function offsetGet($offset) { $this->callCount++; if ($this->callCount == 1){ $r = $this; } else { $r = "callback"; } return $r; } } $a = new A $a->bindTo($test); $test->foo = $a; // end editing here echo $test->run();