At 09:27 AM 1/11/05 -0800, Michael Chermside wrote:
Phillip:

I think you must inhabit a far more perfect world than I do.

You say, for instance, that:
> ...-1 if this introduces a performance penalty [...] just to
> support people who want to create deliberate Liskov violations.
> I personally don't think that we should pander to Liskov
> violators

I've since dropped both the performance objection and the objection to supporting Liskov violation; in a more recent post I've proposed an alternative algorithm for allowing it, that has a simpler implementation.



You say that:
> I think one should adapt primarily to interfaces, and
> interface-to-interface adaptation should be reserved for
> non-lossy, non-noisy adapters.

... but in my world, half the time I'm using adaptation to
correct for the fact that someone else's poorly-written
code requests some class where it should have just used
an interface.

PEP 246 adaptation? Or are you talking about some other language? (I ask out of curiosity.)


I agree that if it's possible to adapt to concrete types, people will do so. However, I think we all agree that this isn't a great idea and should still be considered bad style. That's not the same thing as saying it should be forbidden, and I haven't said it should be forbidden.


You seem to inhabit a world in which transitivity of adaptation
can be enforced. But in my world, people occasionally misuse
adaptation because they think they know what they're doing
or because they're in a big hurry and it's the most convenient
tool at hand.

How is this different from abuse of *any* language feature that you're then forced to work around? Are you saying we should not provide a feature because *some* people will abuse the feature? I don't understand.


If you allow interface inheritance, you're just as susceptible to an invalid adaptation path, and in my experience this is more likely to bite you unintentionally, mainly because interface inheritance works differently than class inheritance (which of course is used more often). Do you want to prohibit interface inheritance, too?

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