Re: [Pyobjc-dev] Using python classes in objc...

[Jiva D. <ji...@de...>]

That is exactly what I was looking for!

Thank you so much!

On Mar 10, 2004, at 10:19 AM, b.bum wrote:

> On Mar 10, 2004, at 9:01 AM, Jiva DeVoe wrote:
>> How do I get around this problem?  BBum has mentioned using a factory 
>> method in an abstract superclass.  Ok, that's fine, but even then, 
>> the factory method still has to instantiate the python class.  How 
>> does it do so without linking the python code?
>
> Do something like:
>
> @implementation MyFactoryAbstractObjCClassyThing
> + createAConcreteInstance
> {
> 	Class aClass = 
> NSClassFromString(@"ConcretePythonSubclassOfThisClass"); // only works 
> if you had previously imported the appropriate code in python
>
> 	return [[aClass alloc] init];
> }
>
> To avoid compiler warnings when messaging the class, you can:
>
> - declare the methods on a category of the abstract super.   
> Categories do not have to have an associated implementation.  
> Alternatively, you can provide abstract implementations of the methods 
> that do something like:
>
> - (void) methodThatIsReallyImplementedInPython
> {
> 	@throw [NSException exceptionWithName: 
> NSInternalInconsistencyException reason: @"Subclass must implement 
> this." userInfo: nil];
> }
>
> - use -performSelector:, -performSelector:with: and friends to 
> indirectly invoke the method
>
> - make all your functionality Key-Value Coding and use Bindings and/or 
> -setValue:forKey: and -valueForKey: (not really practical for anything 
> but data passing)
>
> - use NSInvocation to build up the method invocation
>
> I generally go with the first option:
>
> @interface Abstract:NSObject
> + instatiateSubclassNamed: (NSString *) aClassName;
> @end
>
> @interface Abstract(MethodsThatMustBeInPythonSubclass)
> ...
> @end
>
> Then, in python:
>
> class Foo(Abstract)
> 	def ....:
>
>
--
Jiva DeVoe
jiva at devoesquared.com
http://www.devoesquared.com