object inheritance

Anand anandology at gmail.com
Wed Oct 31 23:26:17 CET 2007


On Oct 31, 9:57 am, "Gabriel Genellina" <gagsl-... at yahoo.com.ar>
wrote:
> En Wed, 31 Oct 2007 00:36:34 -0300, Anand <anandol... at gmail.com> escribió:
>
> >> No, that is an argument for multiple-inheritance, mixin classes etc. You
> >> know when constructing the object what behaviour you want it to have. It
> >> isn't an argument for changing the behaviour of an existing object
> >> dynamically.
> > Partially true. I don't want to change the behavior of an exiting
> > object. I know what behavior I want to have at the time of creating.
> > This can be achieved by creating classes dynamically by parameterizing
> > the base class, which I thought is ugly.
>
> If you know at compile time which features you want, you can use multiple
> inheritance to define the new class.
> If you only know the set of clases to mix at run time, you can dinamically
> create new classes with 'type':
>
> newclass = type('newclass', (CachedDB, SimpleDB), {})
> db = newclass()
> db.withIDs will call CachedDB.withID, as you want.

Interesting.

CachedDB.withID should call withID from its super class (here
SimpleDB), when it is not in cache. How to do that?





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