3v4l.org

run code in 300+ PHP versions simultaneously
<?php $a = ['a']; function &set_a($value) { static $a = []; if (!in_array($value, $a, TRUE)) { $a[] = $value; } return $a; } $a = &set_a('a'); while ($value = current($a)) { var_dump($value); set_a('b'); next($a); }

preferences:
31.29 ms | 407 KiB | 5 Q