idioms for abstract base classes

[Carlos Ribeiro]

At 13:18 24/04/01 -0700, zooko at zooko.com wrote:
>Eventually, we started just undoing the inheritance -- I changed
>CryptoCommsHandler to just implement all of its methods instead of using 
>any of
>the ones inherited from BaseCommsHandler, and next time I touch 
>TCPCommsHandler
>I'll do the same to it.  Then we can nuke DummyCommsHandler (which is only 
>good
>for testing the unused "chaining" feature anyway) and CommsHandler and
>BaseCommsHandler.  It will feel really good to get rid of those after all the
>trouble they've caused.

This is the kind of problem that could be solved with interfaces. We had a 
lot of discussions on that, and the PEPs are still pending. The discussion 
is (as far as I recall) if Python needs some explicit support for 
interfaces. Some people feel that we can use interfaces nicely in Python 
today, just by documenting it carefully, and using the dynamic nature of 
the language. You are not trapped by a rigid hierarchy; object similarities 
are handled through their support of interfaces, instead of using inheritance.


Carlos Ribeiro