3v4l.org

run code in 300+ PHP versions simultaneously
<?php interface Foo {} class Bar implements Foo {} var_dump(is_a('Bar', 'Foo', true)); var_dump(is_a('Bar', 'Bar', true)); var_dump(is_subclass_of('Bar', 'Foo')); var_dump(is_subclass_of('Bar', 'Bar'));

preferences:
40.38 ms | 402 KiB | 5 Q