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Date: Wed, 18 Nov 2009 11:59:48 -0800
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Subject: Re: [PHP-DEV] The inconsistencies/flaws of PHP5's object model
From: stas@zend.com (Stanislav Malyshev)

Hi!

> I've just occured a syntax problem in the following script:
> 
> <?php
> class C {
>     public $n = 1;
> }
> $o = new C();
> $o->f = function () use ($o) {
>     echo $o->n;
> };
> $o->f();
> ?>
> 
> The result of this script is "Fatal Error: Call to undefined method C::f()".
> I don't know this is the expected result. After trying more tests of

Yes, this is the expected result. PHP is not Javascript, sorry :) 
Methods and properties are different things in PHP, so the syntax 
assumes you refer to method when you call $o->f(). You could use other 
syntaxes if you need to use a property as callable (see 
call_user_function, etc.).

> 1. There is no way to add/remove instance-level members (both properties and
> methods) to class dynamically, but a way to add them to instance itself,
> which is a little buggy as above codes turns out;

It is not "buggy", it is how the language is - class is a fixed 
template, object is a mutable instance of this template.

> 3. There are __get(), __set(), __call() for instance-level members, and
> __callStatic() for static methods, but lacks __getStatic() and __setStatic()
> for static properties;

That may be added if somebody provides a good patch.

> 4. While using static class as object (general concept of "object", not
> "instance" here), it's extremely complex to simulate "prototype object", as
> static members simply do not duplicate themselves at all while inheriting,
> therefore all of the child classes share a single static member of the
> parent class;

That's how static members work - they belong to the defining class.

> 6. Static methods are allowed in interfaces, but not allowed in abstract
> class, which breaks the rule of abstraction;

You can have static functions in abstract classes. What you can not have 
is abstract static functions, because it makes little sense - static 
function belongs to the class, so if it's abstract - meaning needs to be 
redefined - then what exactly you are defining? You'll define static 
functions in child classes anyway and you'll be calling them explicitly 
by class name (i.e. ChildClass::foo, not BaseClass::foo).

> 7. An interface which has only static methods cannot ensure static methods
> in a class which implements it.

I'm not sure what you mean here, could you provide a short code example 
that you think should be working and doesn't?

-- 
Stanislav Malyshev, Zend Software Architect
stas@zend.com   http://www.zend.com/
(408)253-8829   MSN: stas@zend.com