This article is very outdated. PHP has closures, can natively pass callables as arguments and you don't need any of these workarounds:<p><a href="https://www.php.net/manual/en/functions.anonymous.php" rel="nofollow">https://www.php.net/manual/en/functions.anonymous.php</a><p>It's not <i>idiomatic</i> to do so, but you can totally write sort of functional PHP nowadays without any tricks. Stuff like `array_map` exists since PHP 4.