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Re: Error objects in general

This page is part of the web mail archives of SRFI 77 from before July 7th, 2015. The new archives for SRFI 77 contain all messages, not just those from before July 7th, 2015.

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.

Using RELAX NG compact syntax to        John Cowan
develop schemas is one of the simple    http://www.reutershealth.com
pleasures in life....                   http://www.ccil.org/~cowan
        --Jeni Tennison                 <jcowan@xxxxxxxxxxxxxxxxx>