NaN's Paul Schlie (29 Oct 2005 15:50 UTC)
Re: NaN's Marcin 'Qrczak' Kowalczyk (29 Oct 2005 16:39 UTC)
Re: NaN's Paul Schlie (29 Oct 2005 18:22 UTC)
Re: NaN's Marcin 'Qrczak' Kowalczyk (29 Oct 2005 19:14 UTC)
Re: NaN's Paul Schlie (29 Oct 2005 22:49 UTC)
Error objects in general bear (29 Oct 2005 19:46 UTC)
Re: Error objects in general Marcin 'Qrczak' Kowalczyk (29 Oct 2005 20:22 UTC)
Re: Error objects in general bear (30 Oct 2005 05:57 UTC)
Re: Error objects in general Marcin 'Qrczak' Kowalczyk (30 Oct 2005 14:17 UTC)
Re: Error objects in general Alan Watson (29 Oct 2005 21:26 UTC)
Re: Error objects in general bear (30 Oct 2005 05:40 UTC)
Re: Error objects in general Taylor Campbell (30 Oct 2005 05:45 UTC)
Re: Error objects in general bear (30 Oct 2005 06:08 UTC)
Re: Error objects in general Taylor Campbell (30 Oct 2005 16:49 UTC)
Re: Error objects in general Alan Watson (30 Oct 2005 05:54 UTC)
Re: Error objects in general bear (30 Oct 2005 06:07 UTC)
Re: Error objects in general Alan Watson (30 Oct 2005 06:46 UTC)
Re: Error objects in general Paul Schlie (30 Oct 2005 12:39 UTC)
Re: Error objects in general Paul Schlie (30 Oct 2005 13:04 UTC)
Re: Error objects in general John.Cowan (30 Oct 2005 16:30 UTC)
Re: Error objects in general Alan Watson (30 Oct 2005 20:29 UTC)
Re: Error objects in general Alan Watson (30 Oct 2005 13:17 UTC)

Re: Error objects in general John.Cowan 30 Oct 2005 16:30 UTC

Paul Schlie scripsit:

> Overall the question is: if NaN's (aka <indeterminate>/<void> values) are
> to be embraced, should their observable effect be more generally defined
> throughout the entire language specification? (As otherwise the ambiguities
> they represent may either be obscured by subsequent evaluations, or result
> in potentially undesirable non-easily foreseen halting errors?)
>
> [or alternatively should all arithmetic operations always return well
> specified deterministic numeric values, thereby eliminating the otherwise
> necessity for a <indeterminate>/<void>/<nan> value object?]

This is the fallacy of false dichotomy.  All flonum arithmetic operations
do always return well-specified deterministic values; however, some of them
are not numbers.  What's more, this is what all Scheme implementations on
non-ancient hardware provide in practice.  A NaN is not an indeterminate
value; it is a determinate non-numeric value, disjoint from all other
Scheme values.

--
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