all you have to do is ADD def __conform__(self, protocol): if issubclass(protocol, Abstract): raise LiskovViolation
that's all.
That will raise a TypeError if protocol is not a class or type, so this could probably serve as an example of how difficult it is to write a good Liskov-violating __conform__. :)
Actually, there's another problem with it; if you do this:
class Y(X): pass
class Z(Y): passthen 'adapt(Z(),Y)' will now fail because of a Liskov violation. It should really check for 'protocol is Abstract' or 'protocol in (Abstract,..)' in order to avoid this issue.
Basically, rephrasing private inheritance with containment and delegation is a lot of messy work, and results in far more complicated structures. And instead of paying the tiny price of a __conform__ call at adaptation time, you pay the price of delegating calls over and over at each x.tm1() call, so it's unlikely performance will improve.
Well, as I mentioned in my other post, such inheritance is a lot simpler with PEAK, so I've probably forgotten how hard it is if you're not using PEAK. :) PEAK also caches the delegated methods in the instance's __dict__, so there's virtually no performance penalty after the first access.
Again, not an argument that others should use PEAK, just an explanation as to why I missed this point; I've been using PEAK's delegation features for quite some time and so tend to think of delegation as something relatively trivial.
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