3v4l.org

run code in 200+ php & hhvm versions
Bugs & Features
<?php preg_match('/^((?:(?:[^?+*{}()[\\]\\\\|]+|\\\\.|\\[(?:\\^?\\\\.|\\^[^\\\\]|[^\\\\^])(?:[^\\]\\\\]+|\\\\.)*\\]|\\((?:\\?[:=!]|\\?<[=!]|\\?>)?(?1)??\\)|\\(\\?(?:R|[+-]?\\d+)\\))(?:(?:[?+*]|\\{\\d+(?:,\\d*)?\\})[?+]?)?|\\|)*)$/', '~1~', $matches); var_dump($matches);
Output for 4.3.0 - 7.2.0
array(2) { [0]=> string(3) "~1~" [1]=> string(3) "~1~" }