[Python-Dev] PEP 246, redux

[Paul Moore]

On Wed, 12 Jan 2005 00:33:22 +0100, Alex Martelli <aleax at aleax.it> wrote:
> But adaptation is not transmission!  It's PERFECTLY acceptable for an
> adapter to facade: to show LESS information in the adapted object than
> was in the original.  It's PERFECTLY acceptable for an adapter to say
> "this piece information is not known" when it's adapting an object for
> which that information, indeed, is not known.  It's only CONJOINING the
> two perfectly acceptable adapters, as transitivity by adapter chain
> would do automatically, that you end up with a situation that is
> pragmatically undesirable: asserting that some piece of information is
> not known, when the information IS indeed available -- just not by the
> route automatically taken by the transitivity-system.

[Risking putting my head above the parapet here :-)]

If you have adaptations A->B, B->C, and A->C, I would assume that the
system would automatically use the direct A->C route rather than
A->B->C. I understand that this is what PyProtocols does.

Are you mistakenly thinking that shortest-possible-route semantics
aren't used? Maybe the PEP should explicitly require such semantics.

If I'm missing the point here, I apologise. But I get the feeling that
something's getting lost in the discussions.

Paul.