Paul Schlie wrote:
> 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?)

It seems reasonable to specify:

(a) The rules for arithmetic on NaNs.

(b) The behaviour of eqv? on NaNs.

(c) The read and write syntax of NaNs, if these exist.

(d) That calling inexact->exact on a NaN signals an error.

Provided one maintains (d), the effects of NaNs are limited.

Regards,

Alan
--
Dr Alan Watson
Centro de Radioastronomía y Astrofísica
Universidad Astronómico Nacional de México