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

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@iamjochem.com> 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. -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php

-- http://www.web-buddha.co.uk dynamic web programming from Reigate, Surrey UK (php, mysql, xhtml, css) look out for project karma, our new venture, coming soon!