Re: [PHP-DEV] adding objects with + equal to array process From: Kristian Köhntopp (kk <email protected>)
Date: 07/05/00

waldschrott wrote:
> KK> If you are treating objects like arrays, you probably
> KK> should have used arrays in the first place.
>
> You´re right. I´m using PHP objects sometimes like arrays, for the
> reason that PHP allows it, I prefer...

PHP allows it, but that does not mean that it is a good
choice to do it. Using PHP objects as hashes means that
you get all the functionality of objects with your hashes,
which is exactly what you do not need at that moment.

> Ok. PHP objects *should* not be used that way, it´s my fault. I should
> use arrays, then I´ve array functions available. But it´s enticing - PHP
> allows it, and it even uses it.

I think it is a mistake. It is at least bad style to do this,
as you have experienced: It hurts when you do it.

> in fact with *normal* objects which have been instanciated and weren´t
> create with settype() that shouldn´t be possible

That is another weakness in the language, which leads to
abominations such as stdClass. PHP reports the TYPE of
"$o = new C;" as "object", but does not report the CLASS
of $o. That means that classes are not types and when you
set the type of a variable to object, it has no class at
all.

What is an object? Think of it as I have outlined in a
previous post, as a hash containing all instance variables
plus a hidden variable "isa" pointing to the class of
that object. You can serialize() that easily to
(classname, name/type/value of all instance variables).

What is a class? Think of it as I have outlined, as
a hash containing all instance methods, plus all
class variables, plus all class methods plus hidden
instance variable "isa" pointing to Metaclass. At the
moment you cannot properly serialize() that. One
way to serialize that is to generate autoloader
code for the include file defining that class, but
that assumes a 1:1 relationship between classes and
files.

It would be much more elegant to serialize() a class
as the values of all class variables, plus the compiled
bytecode of all instance and class functions. That way
you break the 1:1 relationship between classes and
include files, you get an easy way to manipulate precompiled
bytecode, and you solve the undefined class problem
when using session variables, as the code of serialized
objects becomes part of the session (and then you
store session objects in shared memory, and the magic
really happens, but that is for another discussion).

Kristian 

-- 
Kristian Köhntopp, NetUSE AG Siemenswall, D-24107 Kiel
Tel: +49 431 386 436 00, Fax: +49 431 386 435 99
Using PHP3? See our web development library at http://phplib.netuse.de/

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