Re: [Pyobjc-dev] pickled Objective-C objects

[<bb...@ma...>]

On Monday, Feb 24, 2003, at 04:48 US/Eastern, Just van Rossum wrote:
>>> __init__/tp_init method. Calling an ObjC class will then still
>>> result in that exception, while still properly supporting __new__.
>>>
>> Class clusters may be problematic here (in combination with pickling).
>> If you create an NSArray you actually end up with a subclass of
>> NSArray. This should be pickled as if it is an NSArray (Apple might
>> replace the classes implementing NSArray by a completely different set
>> of classes).
>
> Yes, it abviously need to support classForCoder. But I would expect  
> that
> NSArray.alloc().initWithCoder() is the right thing, no? If so, aliasing
> __new__ to alloc() is quite natural.

While I can't find the reference in the documentation, I'm fairly  
certain you are not supposed to directly invoke -initWithCoder:.

file:///Developer/Documentation/Cocoa/TasksAndConcepts/ 
ProgrammingTopics/Archiving/index.html#//apple_ref/doc/uid/10000047i

Somewhere in there, an NSArchiver/NSUnarchiver must be used to  
recompose the archived object graph.  That is, you would use  
NSUnarchiver's..

+ unarchiveObjectWithData:fp12;
+ unarchiveObjectWithFile:fp12;

... methods to unarchive the data.   This takes care of all of the  
potential referential cycles that may be present in the object graph  
(example:  if an array contains the same object three times, it'll be  
decoded as one instance with three references / retains in the array).

b.bum
(Who hadn't been paying close enough attention to the conversation to  
know whether or not the above is 100% relevant).