Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:7871
Return-Path: <zeev@zend.com>
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Delivered-To: mailing list internals@lists.php.net
Received: (qmail 68448 invoked by uid 1010); 16 Feb 2004 09:39:12 -0000
Delivered-To: ezmlm-scan-internals@lists.php.net
Delivered-To: ezmlm-internals@lists.php.net
Received: (qmail 68339 invoked from network); 16 Feb 2004 09:39:10 -0000
Received: from unknown (HELO mail.zend.com) (192.117.235.230)
  by pb1.pair.com with SMTP; 16 Feb 2004 09:39:10 -0000
Received: (qmail 11645 invoked from network); 16 Feb 2004 09:39:04 -0000
Received: from localhost (HELO zeev-laptop.zend.com) (127.0.0.1)
  by localhost with SMTP; 16 Feb 2004 09:39:04 -0000
Reply-To: zeev@zend.com
Message-ID: <5.1.0.14.2.20040216113631.06f80cd8@localhost>
X-Sender: zeev@localhost
X-Mailer: QUALCOMM Windows Eudora Version 5.1
Date: Mon, 16 Feb 2004 11:39:00 +0200
To: Hans Lellelid <hans@velum.net>
Cc: internals@lists.php.net
In-Reply-To: <40305B44.20002@velum.net>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"; format=flowed
Subject: Re: [PHP-DEV] extending interfaces - fringe behavior
From: zeev@zend.com (Zeev Suraski)
References: <40305B44.20002@velum.net>

At 07:55 16/02/2004, Hans Lellelid wrote:
>I have a need in a current application to extend interfaces and possibly 
>re-define (change signature) some of the inherited methods in the child 
>interface.
>
>e.g.
>
>interface Foo {
>         public function __construct(MyCls $var);
>         public function myFunction();
>}
>
>interface Bar extends Foo {
>         public function __construct(MyCls $var, $var2 = null);
>         public function myOtherFunction();
>}
>
>class A implements Bar {
>         public function __construct(MyCls $var, $var2 = null) {
>                 // ...
>         }
>         public function myFunction() {
>                 // ...
>         }
>         public function myOtherFunction() {
>                 // ...
>         }
>}
>
>This is not currently possible in PHP5b4, due to the (new?) "Can't inherit 
>abstract function" errors generated by the engine.  I.e. if I try to 
>redefine __construct() I will get an error.
>
>The need for this capability is probably not that mainstream, but it'd be 
>very nice.  Is there any chance of having support for this behavior?  I 
>don't know anything about the underlying mechanism for supporting 
>interface extension, so I don't know if what I'm asking is trivial or not.

You're not supposed to change the signature when you're 
extending/implementing interfaces.  I'll try to see if it's feasible to 
improve the checks so that they compare signatures in a smarter way (i.e., 
func($arg1, $arg2=null) is  compatible with func($arg1), and currently it's 
not detected that way).

Zeev