Re: [Pyobjc-dev] Re: [Pythonmac-SIG] pyobjc / cocoa

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

On Thursday, Oct 17, 2002, at 20:29 Europe/Amsterdam, Bill Bumgarner 
wrote:

> On Thursday, October 17, 2002, at 02:01 PM, Bob Ippolito wrote:
>> IMHO there should also be easy to use wrappers for NSNumber and 
>> NSData.. I use those on a pretty regular basis for stuff that needs 
>> to get serialized for DO or plists.
I'd prefer not to special case Objective-C classes in the extension 
module. We currently do so for NSString and NSNumber, and I'd prefer to 
not add other exceptions.

>
> Wrapping NSNumber and NSData is definitely on the radar, but there is 
> some subtlety in how they need to be wrapped.   I totally agree that 
> they should be wrapped in some fashion.
>
> On the ObjC->Python front, do you mean:
>
> [bumbox:~] bbum% python
> Python 2.2 (#1, 07/14/02, 23:25:09)
> [GCC Apple cpp-precomp 6.14] on darwin
> Type "help", "copyright", "credits" or "license" for more information.
> >>> from Foundation import *
> >>> a = NSMutableArray.array()
> >>> d = NSMutableDictionary.dictionary()
> >>> a.addObject_("a")
> >>> a[0]
> 'a'
> >>> d['foo'] = 'bar'
> >>> d['baz'] = 'bob'
> >>> d.keys()
> ['baz', 'foo']
> >>> d.description()
> '{baz = bob; foo = bar; }'
> >>> d.objectForKey_('baz')
> 'bob'
> >>> d['baz']
> 'bob'
>
> Already in there -- just not quite complete.

The current mechanism is a bit of a hack: the 'objc' module maintains a 
list of methods that are added if a selector is present in the 
objective-C class (e.g. if the class has 'objectForKey:' add an 
__getitem__ method that calls objectForKey_). This should work for most 
collection classes.

>
>> Does pyobjc do garbage collection?  I'd imagine that you could have 
>> the __init__ for anything to a retain and the __del__ for anything do 
>> a release without getting in the way..

Pyobjc tries very hard to maintain correct retainCounts on the 
Objective-C object. In general it should not be necessary to think 
about this.

Please tell the list if you do have to call 'retain' or 'release', upto 
now I've been able to find a generic solution for every instance where 
I had to take care of retainCounts in Python code.

Ronald