On Tue, Mar 16, 2010 at 9:07 AM, Mark Dickinson <dicki...@gmail.com> wrote: > On Tue, Mar 16, 2010 at 4:41 PM, Guido van Rossum <gu...@python.org> wrote: >> I'd say if you're not going to forward-port this to Python 3, it >> shouldn't go into Python 2 -- in that case it would make more sense to >> me to back-port the exception-raising behavior. > > That's also a possible solution, and the one that I'd personally be > happiest with. The main problem is that this has the potential to > break code: lists containing both floats and Decimals are sortable in > 2.6, but would no longer be sortable in 2.7. If such breakage is > deemed acceptable then I'd happily backport the exception; I really > don't have a good feeling for how much real-world code could break, if > any.
Definitely some. Stricter comparison rules are a frequent cause of problems when code is first ported to 3.x. While you'd think that code comparing a float and a Decimal is *already* broken, there's a surprising number of situations where that's not necessary the case, e.g. when an arbitrary but stable ordering is needed. >> Also supporting comparisons but not other mixed operations is going to >> be confusing. If you are sticking to that behavior I think mixed >> comparisons should also be ruled out. > > Confusing, yes, but at least not bug-prone. The current 2.x behaviour > has provoked complaints from a number of different people in various > different fora (I recently saw this come up on StackOverflow), and > after initially being skeptical I'm now convinced that it would be a > good idea to change it if at all possible. Yeah, it should have raised an exception all along. But it's too late for that now. I wonder if it should just become a py3k warning? -- --Guido van Rossum (python.org/~guido) _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
