3v4l.org

run code in 150+ php & hhvm versions
Bugs & Features
<?php $x = ''; $$x = 'empty'; var_dump( ${''} ); $x = 'red'; $$x = 'empty'; var_dump( ${'red'} );
based on Wdrs6
Output for 4.3.0 - 5.6.28, hhvm-3.12.0, 7.0.0 - 7.1.0
string(5) "empty" string(5) "empty"
Output for hhvm-3.10.0

Process exited with code 153.