Compose (unary) functions

composed.php

<?php
declare(strict_types=1);

final class Compose
{
    public static function these(Closure ...$closures): Closure
    {
        return array_reduce($closures, function (Closure $composed, Closure $f): Closure {
            return function ($x) use ($f, $composed) {
                return $f($composed($x));
            };
        }, function ($x) { return $x; });
    }
}