PHP currying with placeholder support

gistfile1.php

<?php
class Placeholder{}
function curry(callable $func, ... $curriedArgs) {
	return function(...$fulfillment) use ($func, $curriedArgs) {
		return $func(...array_merge(array_map(function($arg) use ($fulfillment) {
			if ($arg instanceof Placeholder)
				return array_shift($fulfillment);
			return $arg;
		}, $curriedArgs), $fulfillment));
	};
};


$sum = function ($a, $b, $c) {
	var_dump($a,$b,$c);
	return $a + $b + $c;
};
$sum = curry($sum, 1,(new Placeholder),3);
$sum(2);