[Chicken-hackers] CR: Division by inexact zero should return infinity/nan

[Peter Bex]

Hi all,

I'm working on fixing several bugs in numbers, and now I stumbled
upon Chicken's behaviour with zero-flonums:

(/  1.0 0.0) => error: division by zero
(/ -1.0 0.0) => error: division by zero
(/  0.0 0.0) => error: division by zero

However, an inexact zero is not exactly zero; it could be some
very small value unrepresentable by the internal floating-point
storage.

This is really annoying, as you'd get "random" errors when you're working
with numbers in the extreme ranges representable by flonums even if you
absolutely know you're dividing by nonzero values.

All other Schemes I tested with (Guile, Gauche, Scheme48, Racket and Gambit)
return +inf.0 for (/ 1.0 0.0) and -inf.0 for (/ -1.0 0.0).
They return +nan.0 for (/ 0.0 0.0).  Extra data points would be welcome.

I'd like to open a CR for doing the same in Chicken, to make it behave
like a good little robot.  If it is accepted, a corresponding change will
also be made to the "numbers" egg.  The CR has ticket number #672 in Trac.

Cheers,
Peter
-- 
http://sjamaan.ath.cx
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