Using child classes/interfaces as desired type hints
| From: | Nathan Nobbe | Date: | Thu, 07 Oct 2010 05:56:34 +0000 |
| Subject: | Using child classes/interfaces as desired type hints | ||
| Groups: | php.internals | ||
| Request: | Send a blank email to internals+get-49881@lists.php.net to get a copy of this message | ||
Hi,
Probly rehashing an old conversation here, but I'm wondering why the
following isn't supported
<?php
abstract class AbstractServer {}
class ConcreteServer extends AbstractServer {}
abstract class AbstractClient {
abstract function doStuff(AbstractServer $o);
}
class ConcreteClient extends AbstractClient {
function doStuff(ConcreteServer $o) {}
}
?>
This results in a fatal
Fatal error: Declaration of ConcreteClient::doStuff() must be compatible
with that of AbstractClient::doStuff() in
/Users/quickshiftin/gitRepos/timberline/php-api-v15-client/testOverride.php
on line 11
I was reading a few posts from way back when
http://marc.info/?t=107774904800001&r=1&w=2
yet still find myself wondering. I think it can be said here that if
there's a contract defined by AbstractClient::doStuff, that same contract is
honored by ConcreteClient::doStuff. I also think changing the language to
support this notion wouldn't raise BC issues for the most part (at all?)
since at the moment you're forced to move to the lowest common denominator
in the tree, in this case
class ConcreteClient extends AbstractClient {
function doStuff(AbstractServer $o) {}
}
your feedback appreciated,
-nathan