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Re: Questions about srfi-77 Generic Arithmetic




On Feb 18, 2006, at 11:22 AM, William D Clinger wrote:

8.  Integer Divison.
(a) I think it is a really bad design to have the basic
operation of div+mod change when the second argument changes sign.

I don't have much problem with that.  These mathematical
operations aren't defined at zero, so they have to compare
against zero anyway.  To quote Egner et al, "the sign of
the modulus y determines which system of representatives
of the residue class ring Z/yZ is being chosen, either
non-negative (y > 0), symmetric around zero (y < 0), or
the integers (y = 0)."  Using the sign of y is ad hoc,
but it's an ad hoc choice anyway.

For now, let me just point out

http://groups.google.com/group/comp.lang.scheme/msg/32949cdfdda958f8?

where either you pulled one over on me that I didn't realize, or you didn't know what MODULO meant in 1996. I think introducing this operator will make things very much worse.

Brad