| Date: Fri, 24 Nov 2006 14:36:36 -0600
| From: Alan Watson <alan_at_alan-watson.org>
|
| Other than using eqv?, how would one distinguish between a single
| and a double, when both have the same finite value? One could
| evaluate:
|
| (eq? (infinite? (+ x FLT_MAX FLT_MAX FLT_MAX))
| (infinite? (+ y FLT_MAX FLT_MAX FLT_MAX)))
|
| (where FLT_MAX is the largest finite single). In a Scheme with
| singles and doubles that preserved precision, this would indeed
| yield #f if x and y were of different precisions.
Even a precision-preserving implementation would be within its rights
to return a double from (+ x FLT_MAX FLT_MAX FLT_MAX) because
returning +inf.0 would be a reduction in precision; +inf.0 is very
imprecise.
Received on Fri Nov 24 2006 - 16:34:55 UTC