Re: [Pyobjc-dev] Catergory Question ...

[Mic P. <mic...@gm...>]

Ronald,

So is there no way at all the be able to call a Python pyobj-c class
from Obj-C as from your earlier response you did imply this ??

'...the same is true for methods you add in a subclass, those can be
called from ObjC as well...'

I'm mainly a Obj-C programmer, and have only recently turned to
PyObj-c as a way to utilise many libraries that simply aren't
available to Obj-C, such as for processing Textile and Yaml ?

I have got it working so far using another method I found on the
internet which involves creating a wrapper class for the Python part
and using NSClassFromString to instantiate the class, but I was hoping
to drop these two extra files in favour of just using a header file
and the original Python file like with the category stuff. Is this
then not possible ?

Thank

-Mic


2009/5/10 Ronald Oussoren <ron...@ma...>:
> Mic,
>
> You cannot refer to the class directly in Objective-C, that's because PyObjC
> will create the class at runtime and your ObjC code tries to link to it at
> compile-time.
>
> I tend to write all my code in Python, using ObjC as a way to optimize code
> where needed and to access API's that are not available in Python.  This
> means I tend to be able to get away with creating instances in Python code,
> while still calling methods on them in ObjC.
>
> Ronald
>
> On 10 May, 2009, at 18:26, Mic Pringle wrote:
>
>> Hi Ronald,
>>
>> As you have probably seen, I now have categories working fine, thanks
>> to your help.
>>
>> You mentioned in one of your earlier replies that I can also do the
>> same for subclasses, not just categories. So following this I have
>> created a header file in Objective-C with the following contents ...
>>
>> #import <Cocoa/Cocoa.h>
>>
>> @interface BKTextile : NSObject
>>
>> - (NSString *)decodeTextile:(NSString *)aString;
>>
>> @end
>>
>> And then created the following Python implementation ...
>>
>> from Foundation import *
>> import textile
>>
>> class BKTextile(NSObject):
>>
>>        def decodeTextile_(self, aString):
>>                return u"it worked!"
>>
>> Which is pretty much what I've done to get the category to work,
>> except when I try to compile I get the following error ...
>>
>> .objc_class_name_BKTextile referenced from:
>> literal-pointer@_OBJC@__cls_refs@BKTextile in PythonServerTest.o
>> symbol(s) not found
>>
>> Any ideas ??
>>
>> Thanks,
>>
>> Mic
>>
>>
>> 2009/5/8 Ronald Oussoren <ron...@ma...>:
>>>
>>> On Friday, May 08, 2009, at 10:59AM, "Mic Pringle" <mic...@gm...>
>>> wrote:
>>>>
>>>> Hi,
>>>>
>>>> Just a quick question regarding categories.
>>>>
>>>> I have a hybrid Obj-c/PyObj-c application and I'd like to know if I
>>>> add a category in a PyObj-c module, will it be availble to use in the
>>>> Obj-c side of the project ??
>>>>
>>>> If so, does it just work or are there any special instructions I need
>>>> to follow to get it working ?
>>>
>>> Methods you add using an Python category are available in ObjC as well
>>> (the same is true for methods you add in a subclass, those can be called
>>> from ObjC as well).
>>>
>>> Two possible sources for confusion/problems:
>>>
>>> * Unless the methods you add are already known to the compiler you'll
>>> have to write a header file that the ObjC compiler
>>>  can use. You'll get compiler warnings otherwise.
>>>
>>> * Methods that you add in python by default have arguments and a return
>>> value of type 'id'. This can be overridden by:
>>>
>>>  - information extracted from the superclass (if you override a method
>>> PyObjC knows the new method should have the
>>>    same signature as the one in a superclass).
>>>  - the method is defined in an informal_protocol that's known to PyObjC,
>>> the method signature is then extracted from
>>>    that protocol
>>>  - manual annotations (objc.accessor, objc.selector, ....)
>>>
>>> Ronald
>>>>
>>>> Thanks
>>>>
>>>> -Mic
>>>>
>>>>
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>
>