multiple extensions to a class

[John Lenton]

On Thu, 8 Jul 2004 23:01:52 -0400, Humpty Dumpty
<oliver.schoenborn at utoronto.ca> wrote:
> Hello, I'm experimenting with different ways of extending a class (for a
> plug-ins framework for a GUI) with more than one extension when some of
> these extensions need to collaborate, but others mustn't know about each
> other.
> 
> I.e.,  if I have a class A, and I want to add a block of functionality, I
> can derive it into a B that adds that fucntionality. If I want to add more
> functionality, I can derive B into a C. But if I want to add a third bit of
> functionality D directly to A, such that D knows nothing about B or C, I
> won't be able to instantiate an object that has all three extensions, namely
> an "ABCD". It will either be an "ABC" or an "AD".
> 
> One possibility would be to define the extensions B,C and D as functions and
> add those functions to A with new.instancemethod. Any other ideas on how to
> do this? E.g. is it possible to *add* base classes to a class? I could add
> the extensions by adding them as base classes to A.

maybe I'm missing something, but wouldn't a class E(ABC, AD) work?


-- 
John Lenton (jlenton at gmail.com) -- Random fortune:
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