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);
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.5, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.24 - 5.5.35, 5.6.8 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
array(2) { [0]=> array(2) { [0]=> string(21) "(def a (x) (+ 1 x))" [1]=> string(13) "(print (a 1))" } [1]=> array(2) { [0]=> string(7) "(+ 1 x)" [1]=> string(5) "(a 1)" } }

preferences:
223.19 ms | 406 KiB | 357 Q