[Python-Dev] Re: type categories

[Michael Hudson]

Andrew Koenig <ark@research.att.com> writes:

> David> Oh, easily solved: "in the face of ambiguity, refuse the
> David> temptation to guess".  There should be a best match rule, and
> David> if there are two best matches, it's an error.
> 
> In the ML example I showed earlier:
> 
>        fun len([]) = 0
>          | len(h::t) = len(t) + 1
> 
> ordering is crucial: As long as the argument is not empty, both cases
> match, so the language is defined to test the clauses in sequence.
> My intuition is that people will often want to define category tests
> to be done in a particular order.  There is no problem with such ordering
> as long as all of the tests are specified together.

If multimethods make it into Python, I think (hope!) it's a safe bet
that they will look more like CLOS's multimethods than ML's pattern
matching.

Cheers,
M.

-- 
  ZAPHOD:  You know what I'm thinking?
    FORD:  No.
  ZAPHOD:  Neither do I.  Frightening isn't it?
                   -- The Hitch-Hikers Guide to the Galaxy, Episode 11