counter.php

<?php

function counter() {
	$count = 0;
	
	$incr = function() use (&$count) {
		$count += 1;
		return $count;
	};
	
	$reset = function() use (&$count) {
		$count = 0;
	};
	
	return array($incr, $reset);
}

list($incr1, $reset1) = counter();

$incr1();
$incr1();
var_dump($incr1());  // 3

list($incr2, $reset2) = counter();

$incr2();
var_dump($incr2());  // 2
$reset2();
var_dump($incr2());  // 1
$reset1();
var_dump($incr1());  // 1
var_dump($incr2());  // 2