Re: Polymorphism [was] [Fwd: Re: [PHP] Parents constructor]

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That is not polymorphism - that is multiple inheritance. Java can't do that
either, and uses a much cleaner method - interfaces. And interfaces are
supported in php5. So php does allow it. Not polymorphism - multiple
inheritance. Not multiple inheritance - interfaces.

On 03/05/06, Jochem Maas <jochem@xxxxxxxxxxxxx> wrote:

-------- Original Message --------

On Fri, 2006-03-24 at 10:50, Jochem Maas wrote:
> Pham Huu Le Quoc Phuc wrote:
> > I want to execute polymorphism.
> >

I said (a long time ago):

> ...BUT the OP didn't ask about polymorphism and php
> doesn't support it at all anyway.

Rob replied (also quite a long time ago):

> Ummm, PHP supports polymorphism.. it has at least since PHP 4.
>
>     http://whatis.techtarget.com/definition/0,,sid9_gci212803,00.html
>
> 1 and 3 in the above link are supported. Number 2 is not, however, that

PHP supports 1 - but I have never heard of dynamic typing referred to as
polymorphism.

PHP doesn't support 2 - in so far as you can't define mabny functions with
the same name (but different signatures) - this is usually referred to as
overloading. - granted we have __call() on objects/classes which allows
you
to implement functionality that work like this.

> is usually referred to as function/method overloading and not so often
> by polymorphism. Number 3 is the most common type when discussing
> polymorphism.

in php's case this comes down to the same thing as 1. - dynamic typing of
variables.

BUT there is a fourth form of polymorphism - one I would argue if the
most common form when speaking about polymorphism with respect to
programming,
namely the ability to derive a subclass from more than one base class
(simutaneously),
this is something that php cannot do (thank <deity>).

>
> Cheers,
> Rob.

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