3v4l.org

run code in 150+ php & hhvm versions
Bugs & Features
<?php var_dump(preg_match($r = '[foo\\[[\\d\\s]+\\]]', 'lorem foo[42 37 19 ] ipsum', $m), $m); echo "$r\n";
based on q0vDY
Output for 4.3.0 - 7.1.0
int(1) array(1) { [0]=> string(14) "foo[42 37 19 ]" } [foo\[[\d\s]+\]]