Closure Memoization in PHP

gistfile1.php

<?php
function Memoize($function) {
	
	$cache = array();
	return function() use (&$cache, $function) {		
		$args = func_get_args();
		$serialized = serialize($args);
		
		if( isset($cache[$serialized]) )
			return $cache[$serialized];
		
		$val = call_user_func_array($function, $args);
		$cache[$serialized] = $val;		
		return $val;
	};
	
}








function Benchmark($name, $runs, $function) {
	$start = microtime(true);
	while( $runs-- ) {
		$function();
	}
	$end = microtime(true);
	echo $name.": ".($end - $start)."\n";
}



$fib = function($n) use (&$fib) {
	if( $n < 3 )
		return 1;
	else
		return $fib($n - 1) + $fib($n - 2);
};

Benchmark('$fib(15)', 900, function() use ($fib) {
	for( $i = 0; $i < 20; $i++ ) {
		$fib($i);
	}
});




$fib = Memoize($fib);

Benchmark('Memoized $fib(15)', 900, function() use ($fib) {
	for( $i = 0; $i < 20; $i++ ) {
		$fib($i);
	}
});



/********************
* $fib(15): 6.2607789039612
* Memoized $fib(15): 0.032751083374023
********************/