3v4l.org

run code in 300+ PHP versions simultaneously
<?php $pattern="/\(((?>[^()]+)|(?R))*\)/"; $str = <<< LOL (def a (x) (+ 1 x)) (print (a 1)) LOL; preg_match_all($pattern,$str,$out); var_dump($out);

preferences:
34.92 ms | 402 KiB | 5 Q