[Moshe]
FWIW, I think Python should support Rationals, and have integer division return a rational. I'm still working on the details of my great Python numeric tower change.
[Guido]
Forget it. ABC did this, and the problem is that where you *think* you are doing something simple like calculating interest rates, you are actually manipulating rational numbers with 1000s of digits in their numerator and denumerator.
Let's not be too hasty about this, cuz I doubt we'll get to change it twice <wink>. You (Guido) & I agreed that ABC's rationals didn't work out well way back when, but a) That has not been my experience in other languages -- ABC was unique. b) Presumably ABC did usability studies that concluded rationals were least surprising. c) TeachScheme! seems delighted with their use of rationals (indeed, one of TeachScheme!'s primary authors beat up on me in email for Python not doing this). d) I'd much rather saddle newbies with time & space surprises than correctness surprises. Last week I took some time to stare at the ABC manual again, & suspect I hit on the cause: ABC was *aggressively* rational. That is, ABC had no notation for floating point (ABC "approximate") literals; even 6.02e23 was taken to mean "exact rational". In my experience ABC was unique this way, and uniquely surprising for it: it's hard to be surprised by 2/3 returning a rational, but hard not to be surprised by 6.02e23/1.0001e-18 doing so. Give it some thought.
If you want to change it, consider emulating what kids currently use in school: a decimal floating point calculator with N digits of precision.
This is what REXX does, and is very powerful even for experts (assuming the user can, as in REXX, specify N; but that means writing a whole slew of arbitrary-precision math libraries too -- btw, that is doable! e.g., I worked w/ Dave Gillespie on some of the algorithms for his amazing Emacs calc). It will run at best 10x slower than native fp of comparable precision, though, so experts will hate it in the cases they don't love it <0.5 wink>. one-case-where-one-size-doesn't-fit-anyone-ly y'rs - tim