Edit report at https://bugs.php.net/bug.php?id=46705&edit=1
ID: 46705
Comment by: tklingenberg at lastflood dot net
Reported by: wrzasq at gmail dot com
Summary: Impossible to implement compatible interfaces
Status: Open
Type: Feature/Change Request
Package: Scripting Engine problem
Operating System: Debian GNU/Linux
PHP Version: 5.2.6
Block user comment: N
Private report: N
New Comment:
Actually it's possible, you just need to make the interfaces compatible for
that:
interface A
{
public function foo();
}
interface B extends A
{
}
and then you're done. This also prevents you from writing duplicate code ;)
However if interfaces definitions can not be changed, then this is not a
solution. Probably this is fixed? - See bug #43200.
Previous Comments:
------------------------------------------------------------------------
[2011-08-01 12:11:11] smith at pooteeweet dot org
Note its also not possible to redefine while adding new optional parameters
<?php
interface fooI
{
function ding();
}
interface barI extends fooI
{
function ding($dong = null);
}
class bar implements barI
{
public function ding($dong = null)
{
echo 'woho: '.$dong."\n";
}
}
$bar = new bar;
$bar->ding('yeah!');
------------------------------------------------------------------------
[2011-03-22 23:33:03] clicky at erebot dot net
I think this use case, the one bug #43200 and the one below are all valid:
<?php
interface A
{
public function foo();
}
interface B
extends A
{
public function foo();
}
class C implements B
{
public function foo(){}
}
?>
The case above may seem odd (there's really no point in redefining the exact
same interface), but I have a simple use case where this may prove handy.
I'm currently writing some code for a little project which is meant to teach
some middle to advanced topics of PHP. The code is self-documented (using
doxygen) and uses some interface from SPL (Countable). That interface is used
several times in different files and I'd like to document the count() method
only once (if possible, at the interface level -- then using doxygen's ability
to copy/paste the doc from parent classes/interfaces into the current class).
I thought I could just define my own interface (Project_Countable), extending
from SPL's Countable, "overriding" the method's signature (only so doxygen can
pick up the method's declaration -- the prototype for the method was actually
left unchanged) and then define a class that implements Project_Countable.
So in my case, A = SPL's Countable interface and B = Project_Countable.
However, this pattern can't be used as it results in the same error others
noted here and in bug #43200.
I can't simply avoid Project_Countable extending from Countable, because then I
would lose count()'s "magic" by doing so.
------------------------------------------------------------------------
[2008-11-28 07:57:42] wrzasq at gmail dot com
Description:
------------
It is impossible to implement multiple interfaces that declares same
methods. I saw bug #43200 but this is a bit different case and I
think in this situation it shoud be allowed - those interfaces
requires methods with same signature (also to prevent further
problems - optional parameters should also be allowed to match
signatures):
Reproduce code:
---------------
<?php
interface A
{
public function foo();
}
interface B
{
public function foo();
}
class C implements A, B
{
public function foo(){}
}
Expected result:
----------------
nothing, but working
Actual result:
--------------
Fatal error: Can't inherit abstract function B::foo() (previously
declared abstract in A) in /home/wrzasq/Desktop/Www/engine/- on line
16
------------------------------------------------------------------------
--
Edit this bug report at https://bugs.php.net/bug.php?id=46705&edit=1
