run code in 200+ php & hhvm versions
Bugs & Features
<?php $a = 'something/rel/123/something'; var_dump(preg_replace('#(?<=rel/)(\d+)(?=/)#', 'current', $a));
based on MgfTc

Shows result from various feature-branches currently under review from the php developers. Contact me to have additional branches featured.

Output for Typed properties v2
string(31) "something/rel/current/something"
Output for Lexical anon
string(31) "something/rel/current/something"

Archived branches

Once feature-branches are merged or declined, they are no longer available. Their functionality (when merged) can be viewed from the main output page