Re: [Boa Constr] Boa 2.2 errors (was Re: [wxPython] wxGenButton error in Demo 2.3.2.1)

[Mike C. F. <mcf...@ge...>]

That particular example still works fine in 2.2 (it's even seen in the 
tutorial on type/class unification) ( 
http://www.python.org/2.2/descrintro.html#cooperation ).

 >>> class A:
... 	def m( self ): pass
...
 >>> class B(A):
... 	def m( self ): return A.m( self )
...
 >>> class C( B ):
... 	def m( self ): return A.m( self )
...
 >>> c = C()
 >>> c.m()
 >>> import sys
 >>> sys.version
'2.2 (#28, Dec 21 2001, 12:21:22) [MSC 32 bit (Intel)]'
 >>>

It's a fairly core semantic that an instance of a sub-class should 
always be considered an instance of the base-class, no matter how far 
down the chain it is.  When that changes I'll submit a bug report to 
Python 2.2, rather than Boa ;) .

The error comes from the following, I think:
http://www.python.org/2.2/descrintro.html#incompatibilities

     class A:
         def foo(self): pass

     class B(A): pass

     class C(A):
         def foo(self):
             B.foo(self)

That is, two classes, both of which inherit from A, but _not_ in series 
(i.e. both inherit from A, but they don't inherit from each other).  The 
error now caught is calling _across_ the parallel hierarchy.

You probably knew that and just mis-typed in the email, but thought I 
should make sure :) .

Enjoy,
Mike

Riaan Booysen wrote:
> Hi Mike, these are bugs in Boa.
> 
> This is what's happening:
> 
> class A:
>   def m(self): pass
> 
> class B(A):
>   def m(self): A.m(self)
> 
> class C(B):
>   def m(self): A.m(self)
> 
> c = C()
> c.m()
> 
> This snippet use to be work under Python >= 2.1 (although it is usually 
> a copy paste error) but doesn't under Python 2.2.
> 
> As I've said on the Boa list, I hope to release Boa 0.1.1 soon, as there
> are a few places in the code base this problem occurs.
_______________________________________
   Mike C. Fletcher
   http://members.rogers.com/mcfletch/