cartesian_product.as

/**
 * Return the cartesian product of ...iterables.
 * cartesian_product([1, 2]) => [ [1], [2] ]
 * cartesian_product([1, 2], ["a", "b"]) => [ [1, "a"], [1, "b"], ... ]
 */
public function cartesian_product(...iterables):Array {
	if (iterables.length == 1) {
		return map(function (item:*):Array {
			return [item];
		}, iterables[0]);
	}
 
	var result:Array = [];
	var rest:Array;
	rest = cartesian_product.apply(null, iterables.slice(1, iterables.length));
	for each (var item:* in iterables[0]) {
		for each (var sub_product:Array in rest) {
			result.push([item].concat(sub_product));
		}
	}
 
	return result;
}