3v4l.org

run code in 300+ PHP versions simultaneously
<?php class Foo{ public function __call($n,$a){ return $this->$a->call($this,$a); } } $f=new Foo(); $f->b=function($n){echo$n;}; var_dump($f->b(7));

preferences:
54.76 ms | 402 KiB | 5 Q