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

[Riaan B. <riaan@e.co.za>]

Hi Mike, you are entirely right. Thanks for clearing things up. 

This will teach me to try and teach you, and to wait at least a day 
after installing Python 2.2 before commenting on something ;)

"Mike C. Fletcher" wrote:
> 
> 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/
> 
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-- 
Riaan Booysen
___________________________________________________
Boa Constructor - RAD GUI building IDE for wxPython
     http://boa-constructor.sourceforge.net