php memoize()

memoize.php

<?php
// https://www.youtube.com/watch?v=M3_xnTK6-pA?t=44m18s
// http://eddmann.com/posts/implementing-and-using-memoization-in-php/
//$memoize = function ($function) {
function memoize($function) {
    return function () use ($function) {
        static $cache = [];
        $args = func_get_args();
        $key = md5(serialize($args));
        if (empty($cache[$key])) {
            $cache[$key] = call_user_func_array($function, $args);
        }
        return $cache[$key];
    };
};