On the float behavior: I really wish Python 3 had the sense to do what Perl 6 did and interpret all literals with decimal points (except those that use scientific notation) as Fractions instead of floats. That would solve all these floating-point errors without requiring significant modification of code, plus Python 3 would be the perfect time to do it because they're already throwing out backwards compatibility because of the str/bytes thing.
If Python used the Perl 6 model, you could still use floats by writing your literals in scientific notation, so if you want floating-point performance, you can still get it. For example, 2.2 would be a Fraction, but 2.2e0 would be a float. I don't want to eliminate floats from the language, just hide them from average users by default.
And it's not like rationals-as-default are just some weird Perl 6-ism. Haskell does the same thing, and the language is fairly well-received.
> Also, while nice, Fractions have their own pitfalls due to potentially catastrophic runtime behavior.
