Re: [Pyobjc-dev] Running tests in one python session

[Ronald O. <ous...@ci...>]

On Thursday, May 29, 2003, at 22:53 Europe/Amsterdam, Jack Jansen wrote:

>
> On donderdag, mei 29, 2003, at 21:02 Europe/Amsterdam, Ronald Oussoren 
> wrote:
>> Posing also introduces another, possibly more serious, problem: If 
>> someone poses as NSObject after you import Foundation, 
>> Foundation.NSObject still references the original NSObject (which is 
>> now %NSObject). This can be fixed for 'import Foundation', but not 
>> for 'from Foundation import *'. Sadly enough the latter is how most 
>> peoply import the module.
>
> I thought about this for a while, and I can't see why this is a 
> python-specific problem. If posing modifies the ObjC NSObject in-place 
> then the Python wrapper would see the changes. If posing modifies it 
> out-of-place then ObjC problems should also have the problem that any 
> references to NSObject created before the posing will still refer to 
> the old one.
>
> Or am I missing something (I assume I am, I just don't see it:-)?

It's not the created objects, but the class itself. Objective-C:

	[SomeClass poseAs:[NSObject class]];
	o = [[NSObject alloc] init];

o is now actually an instance of SomeClass. If you do 
cls=objc.lookUpClass('NSObject') in Python (which is basically what the 
Foundation module does) you get a pointer to a class structure. This 
structure is not changed when someone calls poseAs, and therefore 'cls' 
refers to the previous version of NSObject, that is now called 
'%NSObject'. Which means you never really get to see the effects of the 
call to poseAs.

Ronald