[Pyobjc-dev] Making List<->Array bridging transparent

[Bill B. <bb...@co...>]

The following is still broken when bridging ObjC objects into Python.  
I have added a unit test to test this in preparation to actually fix it 
(even though I have *no clue* how to fix it yet :-).

 >>> from Foundation import *
 >>> y = NSMutableArray.arrayWithArray_( range(0,10) )
 >>> x = range(0,10)
 >>> x[1:3] = y
Traceback (most recent call last):
   File "<stdin>", line 1, in ?
TypeError: must assign list (not "NSCFArray") to slice
 >>>

OK... so, how to fix?

It looks like we could augment...

     PyObject* ObjCClass_New(Class objc_class)

... such that if....

     [objc_class isKindOfClass: [NSArray class]]

... is true, then we add <type 'list'> to the bases for the newly 
created Python class object?   Assuming a complete implementation of 
convenience methods, this would allow bridged instances of NSArray to 
function fully on the Python side of the bridge [i.e. work in contexts 
like the above where the runtime is testing for a particular type and 
not just a set of methods].

As an experiment, I tried-- naively-- to add this to the function that 
bridges classes to Python... it doesn't work.

         fprintf(stderr, "Adding.... %s\n\n", objc_class->name);
         if ( [objc_class respondsToSelector: 
@selector(isSubclassOfClass:)] &&
              [objc_class isSubclassOfClass: objc_getClass("NSArray")] ) 
{
           _PyTuple_Resize(&bases, 2);
           PyTuple_SetItem(bases, 1, (PyObject*)&PyList_Type);
           Py_INCREF((&PyList_Type));
         }

......
Adding.... NSArray

Traceback (most recent call last):
   File "Lib/Foundation/test/test_nsexception.py", line 4, in ?
     from Foundation import *
   File "/usr/lib/python2.2/site-packages/Foundation/__init__.py", line 
42, in ?
     class_list = 
load_bundle('/System/Library/Frameworks/Foundation.framework')
   File "/usr/lib/python2.2/site-packages/Foundation/__init__.py", line 
37, in load_bundle
     classes = [ cls
TypeError: multiple bases have instance lay-out conflict

Not sure what to do next....

b.bum