[Python-Dev] Re: Re: lists v. tuples

Guido van Rossum guido@python.org
Sat, 15 Mar 2003 17:45:34 -0500

[Terry Reedy]
> For user-defined types/classes, I presume that this would still mean
> deferring to the appropriate magic method (__cmp__ or __ge__?) to
> define 'meaningful'.

Yes.  And I'm still hoping to remove __cmp__; there should be only one
way to overload comparisons.

> > I'd like to to this in Python 3.0, but that probably means we'd have
> > to start deprecating default comparisons except (in)equality in
> Python
> > 2.4.
> +1, I think.
> Based on reading cl.py, the validity of nonsense comparisons is one of
> the more surprising 'features' of Python for beginners -- who
> reasonably expect a TypeError or ValueError.  Once they get past that,
> they are then surprised by the unstability across versions.  Given
> that universal sorting of hetero-lists is now broken, I think it would
> be better to do away with it cleanly.  It is seldom needed and would
> still be available with a user-defined sorting function (which
> requires some thought as to what is really wanted).


> A Python version of the present algorithm could be included (in
> Tools/xx perhaps) for anyone who actually needs it.

I doubt there will be many takers.  Let people make up their own
version, so they know its behavior.

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