php adaptation of : https://drboolean.gitbooks.io/mostly-adequate-guide/content/ch5.html

functional_example.php

<?php
$compose = function($f, $g){
        return function($x) use ($f,$g) {
                return $f($g($x));
        };
};

$toUpperCase = function($x) {
          return strtoupper($x);
};

$exclaim = function($x) {
        return $x . '!';
};

$shout = $compose($exclaim, $toUpperCase);

echo $shout("send in the clowns");