Re: [Pyobjc-dev] Headache over hacking an XML editor

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

On Tuesday, Jan 14, 2003, at 20:55 Europe/Amsterdam, bb...@ma... wrote:

> On Tuesday, Jan 14, 2003, at 14:46 US/Eastern, Just van Rossum wrote:
>>> There are cases where this will not work -- Ronald has already had to
>>> special case around a number of them.   NSData, NSArray, and NSCell 
>>> (I
>>> think) are examples.    Not because of bugs in Foundation/AppKit, but
>>> because of the implementation pattern used.
>>
>> So how _do_ you instantiate these classes?
>
> Very carefully.  :-)
>
> Have a look at the alloc hack stuff in the source...
The alloc-hack stuff is for another bug/feature of Cocoa. Some classes 
don't like
calls to +alloc through an NSInvocation. I've opened a bugreport for 
this with Apple,
but so far without result.

You have to be a bit carefull: call alloc, some variation of init and 
then adjust the
reference count. Doing it in another order will cause problems some 
times, mostly when
using class clusters.

Ronald