A use for integer quotients

[David Eppstein]

In article <cpae1tboxg.fsf at cj20424-a.reston1.va.home.com>,
 Guido van Rossum <guido at python.org> wrote:

> Well, so far the only arguments I've heard come down to
> 
> (1) int/int *ought* to return an int;
> 
> (2) it breaks too much code to change now.

As one of the people who posted too much to these threads, I'd like to 
clarify my position:
 (1') int/int ought to return an exact value.
I'd be happy with int/int=rational (238+228?). Probably happier than with 
the status quo.  I have code that would break (2) but not too much to 
change. You have talked about bad experiences with unpredictable slowdowns 
with rationals in ABC, but I would prefer my programs to be correct before 
I try to optimize them for speed, and if such a slowdown is found one could 
always put in an explicit float() or // or whatever where needed.

If I really believed that (as the mathematicians usually write) 
floor(int/int) will mean what it means mathematically, rather than some 
worrisome approximation, I would probably use that notation rather than the 
ugly int//int (also that way nobody will get confused and think I mean 
broken C/C++/Java rounding-towards-zero instead of towards -infty, and I 
can use ceiling or round when I mean them instead of adding magic numbers 
before doing the division).

Let me also add that I think generators are a really great addition, so 
2.2 is still moving in very positive directions even if I don't like 
int/int=float.
-- 
David Eppstein       UC Irvine Dept. of Information & Computer Science
eppstein at ics.uci.edu http://www.ics.uci.edu/~eppstein/