On Fri Aug 20 06:54 AM, Jean-Sébastien H. wrote:
> No it's wrong.
>
> A Child is a Parent so we must be able to pass a Parent to the method
> equals() defined on Child.
>
> The declaration of the parent functions must always be valid in the
> children.
>
Maybe my OO theory is wrong but I was under the impression that the only way to
enforce a signature is using an abstract class or interface?
php allows it:
PHP 5.2.13 with Suhosin-Patch 0.9.7 (cli) (built: Aug 14 2010 16:39:00)
PHP 5.3.99-dev (cli) (built: Aug 20 2010 07:45:44)
<?php
class P { function dot(Child $o) { echo "."; } }
class Child extends P { function dot(P $o) { echo "."; } }
$t = new Child;
$t->dot( new P );
$t->dot( new Child );
class P2 { function dot (P2 $o) { echo "."; } }
class Child2 extends P2 { function dot(Child $o) { echo "."; } }
$t = new Child;
$t->dot( new P );
$t->dot( new Child );
?>
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