While Michelangelo Van Dam example (http://br2.php.net/manual/en/class.splheap.php#93930) is a great demonstration of what can be done with SplHeap, this implementation is exactly what SplPriorityQueue does - based on SplMaxHeap. If you're planning to copy that snippet, go no further! There's a SPL class that does exactly what you want :)