Wez Furlong wrote:
An interface is a *public* contract by definition; PPP specifiers just don't make sense there.
out of curiosity:
would that be a definition at the PHP level (i.e. decided by php-devs) or is that definition more widely acknowledged (for want of a better word) (e.g. php-devs used the definition as used in C).
anyway...thanks for knowledge-boost!
This is widely accepted practice. We just have to enforce it in the engine now.
Neither does static, since interfaces are instance based.
where as the argument for PPP is wholly understandable, I can't see the logic in saying that interfaces are per-definition instance based. It is the class that implements the interface, but assuming that indeed interface should be instance based then would it not be correct to assume that interface implementation should only be checked if and when a class is initialized (i.e. so a class is used _only_ statically any interfaces it implements should be ignored), as per the following example (which only works if the 'abstract' is uncommented):
<?php
interface Foo { function foofoo(); }
/* abstract */ class Bar implements Foo { public static function barbar() { echo "bar bar black sheep"; } }
Bar::barbar();
?>
I can understand that interfaces more naturally lean towards use with instances rather than static classes - but it seems to me that forcing that is a case of telling users how they must program (I have always had the impression that PHP tried never to force a particular way of doing things) - not that its a big deal, because in the end a non-static method can be called statically if the user/programmer wishes (and then its his problem to make sure the method in question can handle being called that way, i.e. no refs to $this).
Anyway, thanks very much for taking the time to broaden (at least) my knowledge of PHP.
I tend to agree with Wez here. Interfaces mainly exist so that you can have more instanceof relationships for objects than just one (OK that's an oversimplification but I think it's very much down to earth). That said, there could be instances where it might be useful (such as a Singleton interface) but I don't think it's worth adding such a feature for edge cases. I am very much for simplicity.
Andi
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