This smells like metaclasses to me, just that in your RFC they are
supposed to work on a global level, not on a per class level.
Python, for example, has a magic method called `__new__`, which controls
the creation of the object whenever a new class is instantiated. It
actually allows you to return a different object than the expected one.
I somehow like the proposal, but it may create havoc in some code bases.
I wouldn't really want to see `new FooBar`, when it actually means a
`DamnBar`.
There are also other things to take into consideration. You may want to
override this instantiation mechanism for `FooBar` just in a single
class, not in all of them, which complicates the problem. You'd have to
received the scope where the instantiation is done, but even then, there
may be no way to really know which *object*, not class, wants to
instantiate `FooBar`.
I agree IoC is necessary, but I'm not really sure this is the way to go.
... [some thinking]
At this point, in PHP, classes are global constant symbols. Allowing us
to override the instantiation mechanism would make them global variable
symbols. The below example is already possible in PHP and I believe it
already does what you're asking for (in the current RFC):
class Emailer
{}
$Emailer= 'Emailer';
class FooBar
{
public function sendEmail()
{
global $Emailer;
$emailer = new $Emailer;
}
}
On 11/18/2009 6:06 PM, Robert Lemke wrote:
Hi folks,
after discussing the idea with various PHP developers I now felt safe enough
that it's not a completely stupid idea to post an RFC for it. The idea is to
add support the registration of custom factories which are responsible for
instantiating certain classes.
Here is the first draft of my RFC:
http://wiki.php.net/rfc/customfactories
I suggest that we first discuss the implications and usefulness of this
feature. In a second step I'd need to find some skilled internals wizard who
can implement it, because not being a C developer myself, all I can offer is
making suggestions and fine coffee.
Looking forward to hearing your comments!
Robert
--
Ionut G. Stan
I'm under construction | http://blog.igstan.ro/
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