[Python-ideas] generic Liftable abc-mixin breaks at MRO

[Stephan Sahm]

thanks for the fast response
in fact, I do use this already, however more generically:

def lift(self, new_class, **kwargs):
​    ​
...
​    ​
self.__class__ = new_class
    ...

On 10 December 2015 at 10:33, M.-A. Lemburg <mal at egenix.com> wrote:

> On 10.12.2015 09:58, Stephan Sahm wrote:
> > Dear all,
> >
> > I think I found a crucial usecase where the standard MRO does not work
> out.
> > I would appreciate your help to still solve this usecase, or might MRO
> even
> > be adapted?
> >
> > The idea is to build a generic Lift-type which I call this way because
> the
> > derived classes should be able to easily lift from subclasses. So for
> > example if I have an instance *a* from *class A* and a *class B(A)* I
> want
> > to make *a* an instance of *B* in a straightforward way.
>
> Why don't you use:
>
> a.__class__ = B
>
> ?
>
> >>> class A: pass
> ...
> >>> class B(A): pass
> ...
> >>> a = A()
> >>> a
> <__main__.A instance at 0x7f0bf5ccdc68>
> >>> a.__class__ = B
> >>> a
> <__main__.B instance at 0x7f0bf5ccdc68>
> >>>
>
> --
> Marc-Andre Lemburg
> eGenix.com
>
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