3v4l.org

run code in 150+ php & hhvm versions
Bugs & Features
<?php preg_match('/(?>[A-Za-z])+([A-Za-z])+/', 'FooBar', $m); preg_match('/([A-Za-z])++([A-Za-z])+/', 'FooBar', $m); var_dump($m);
based on CCXgF
Output for 4.3.0 - 7.1.0
array(0) { }