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 sDeh7
Output for 4.3.0 - 7.1.0
string(5) "empty" string(5) "empty"