[Bf-python] Callback types (sorry, got things wrong)

[Michael Reimpell]

> I retract that mess, leaving only this snippet
> for adaptation to the callback translation code:
>
>   PyObject *retval;
>
>   retval=...Call...;
>   if(retval)
>     Py_DECREF(retval);
>   else
>     PyErr_Print();

There should be no need for another error check since a failure of 
PyArg_ParseTuple already leads to a meaningful error message. The 
if( !EXPP_FS_PyCallback )
 		return;
lines of the getSelectedFile function just catch nested calls to 
Blender.Window.ImageSelector/Blender.Window.FileSelector, i.e. Python 
callbacks like
def callback(self, f):
	Blender.Window.FileSelector(anotherCallback)
	return

An implementation that allows nested callbacks would be
static void getSelectedFile( char *name )
{
       PyObject * callback;
       callback = EXPP_FS_PyCallback;

	PyObject_CallFunction( EXPP_FS_PyCallback, "s", name );
        if (callback == EXPP_FS_PyCallback) {
                Py_DECREF(EXPP_FS_PyCallback);
                EXPP_FS_PyCallback = NULL;
        } else {
                /* nested callback */
                Py_DECREF(callback);
        }
	return;
}

Regards,
Michael