On Tue, Mar 16, 2010 at 2:32 PM, Steven D'Aprano <st...@pearwood.info> wrote: > But mixed arithmetic runs into the problem, what do you want the result > type to be? Given (say) decimal+float, returning either a Decimal or a > float will be the wrong thing to do some of the time, so better to > prohibit mixed arithmetic and let folks handle their own conversions. > So +1 on continuing to prohibit mixed arithmetic.
I'm not disagreeing, but I really wonder, what is the value of supporting mixed comparisons then? Just because you *can* assign a meaning to it doesn't mean you should. OTOH I'm sure a lot of people would like to see mixed arithmetic supported, the PEP be damned, and they would probably be happy with any simple rule about the return type even if it's not always ideal. I note that there are cases where converting a long to a float also is the wrong thing to do, and yet mixed long/float operations always return floats. If you are amenable to this argument, I would propose to make the result of mixed operations return a Decimal, since in some "intuitive complexity" sense an int is a simpler type than a float and a float is a simpler type than a Decimal -- so results return the more complex type. But my intuition on this isn't super strong and I could live with always returning a float as well -- there are always casts to force the issue. -- --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
