[Python-Dev] PEP 246, redux (original) (raw)

Paul Moore p.f.moore at gmail.com
Wed Jan 12 15:00:20 CET 2005

On Wed, 12 Jan 2005 00:33:22 +0100, Alex Martelli <aleax at aleax.it> wrote:

By imposing transitivity, you're essentially asserting that, if a programmer forgets to code and register an A -> C direct adapter, this is never a problem, as long as A -> B and B -> C adapters are registered, because A -> B -> C will give results just as good as the direct A -> C would have, so there's absolutely no reason to trouble the programmer about the trivial detail that transitivity is being used. [...] paragraph, then this is just weird: since you're implicitly asserting that any old A->?->C transitive adaptation is just as good as a direct A->C, why should you worry about there being more than one such 2-step adaptation available? Roll the dice to pick one and just proceed.

I know this is out-of-context picking, but I don't think I've ever seen anyone state that A->?->C is "just as good as" a direct A->C. I would have thought it self-evident that a shorter adaptation path is always better. And specifically, I know that Philip has stated that PyProtocols applies a shorter-is-better algorithm.

Having pointed this out, I'll go back to lurking. You two are doing a great job of converging on something so far, so I'll let you get on with it.

Paul.

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