Online PHP editor | refs for v2fY4

@ 2017-07-04T09:44:53Z

<?php

$calc = function ($arg = null, $acc = '') use (&$calc) {
    return $arg === null ? $acc : function ($number = null) use (&$calc, $arg, $acc) {
        return $calc($number, $acc . $arg);
    };
};

$result = $calc(1)(3)(3)(8)();
var_dump($result);