[Python-Dev] type categories

Guido van Rossum guido@python.org
Tue, 13 Aug 2002 22:42:12 -0400

> The main reason I want to be able to LBYL (and, AFAICT, it's the same as
> Alex's reason) is to support multiple dispatch.

But isn't your application one where the types are mapped from C++?
Then you should be able to dispatch on type() of the arguments.  Or am
I misunderstanding, and do you want to make multi-dispatch a standard
paradigm in Python?

> In other words, it wouldn't
> be user code doing the looking. The best reason to support protocol
> introspection is so that we can provide users with a way to write
> more-elegant code, instead of messing around with manual type inspection.
> What's your position on multiple dispatch?

That it's too inefficient in a language with run-time dispatch to even
think about it.

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