3v4l.org

run code in 200+ php & hhvm versions
Bugs & Features
<?php echo preg_replace( '/^(\s+)?$/', 'empty', ' x ' );
based on BJV7P
Output for 5.6.0 - 5.6.30, hhvm-3.18.5 - 3.22.0, 7.1.0 - 7.2.6
x