[R6RS] division by exact zero (again, sorry)

R. Kent Dybvig dyb at cs.indiana.edu
Tue Mar 6 14:09:36 EST 2007

> I would guess that Kent's argument is that the &assertion
> exception that results from (/ 0 0) doesn't count as a
> result.  If the chair of the editors' committee wants the
> R6RS to contain examples that encourage implementors to
> interpret its mandates in specious ways, then I suppose
> (/ 0 3.5) => 0 or 0.0 would do the trick.

No, if we take the text you quoted as a mandate, it's pretty clear that
(/ 0 3.5) should evaluate to 0.0, so I withdraw that part of my comment. 
I believe that the mandate itself and other aspects of R5.92RS arithmetic
are inappropriate for IEEE floating-point arithmetic, but I don't want to
reopen that discussion.

We should probably replace the phrase "One general exception" in the text
you quoted with "The only exception", if we truly want to view the text as
a mandate rather than a guideline.


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