Online PHP editor | refs for DkTQ0

<?php $calc = function ($arg = null, $acc = '') use (&$calc) { return $arg === null ? $acc : function ($n = null, $saved = '') use (&$calc, $arg, $acc) { var_dump($arg); return $calc($n, $saved . $acc . $arg); }; }; $result = $calc(1)(3)(3)(8)(); var_dump($result);