[Python-Dev] PEP 246, redux

[Guido van Rossum]

[Alex]
> I'm saying that if, by mistake, the programmer has NOT
> registered the A->C adapter (which would be easily coded and work
> perfectly), then thanks to transitivity, instead of a clear and simple
> error message leading to immediate diagnosis of the error, they'll get
> a subtle unnecessary degradation of information and resulting reduction
> in information quality.

I understand, but I would think that there are just as many examples
of cases where having to register a trivial A->C adapter is much more
of a pain than it's worth; especially if there are a number of A->B
pairs and a number of B->C pairs, the number of additional A->C pairs
needed could be bewildering.

But I would like to see some input from people with C++ experience.
C++ goes to great lengths to pick automatic conversions (which perhaps
aren't quite the same as adaptations but close enough for this
comparison to work) and combine them. *In practice*, is this a benefit
or a liability?

-- 
--Guido van Rossum (home page: http://www.python.org/~guido/)