(/ 0 4.0) is 0.0, not 0

[ocyzl]

(/ 0 4.0) evaluates to 0.0. I'm not sure this is a bug, but I was expecting 0, like (* 0 0.25). Is there a good reason for the current behavior?

[soegaard]

(/ 0 4.0) evaluates to 0.0. I'm not sure this is a bug, but I was expecting 0, like (* 0 0.25). Is there a good reason for the current behavior?

R6RS has the following example:

(/ 0 3.5)  ⇒  0.0

http://www.r6rs.org/final/html/r6rs/r6rs-Z-H-14.html#node_sec_11.7.4.3

[ocyzl]

Thanks.

After thinking about it some more, I guess the argument is that 3.5, as an inexact number, could conceivably be so inaccurate that it's actually zero, in which case the quotient is undefined, not zero.

[dybvig]

Actually, it doesn't make sense for (/ 0 x), where x is a floating-point number, to be anything other than 0, since a floating-point number is never true 0 (just very small on either side of 0) and never truly infinite (just possibly very large, i.e., the reciprocal of a very small number). We got this wrong in R6RS. We should correct it for the version of / exported by (chezscheme) and leave the broken behavior for (rnrs).

[mflatt]

(/ 0 4.0) is now 0. That / is no longer R6RS's / is a new issue, though, which I'll open next.