[r6rs-discuss] [Formal] Formal Comment: NaN should be considered a number, not a real

[Joe Marshall]

> John Cowan wrote:

> That's what is so excellent about the R6RS definition. 0/0 is
> undefined
because any number times 0 is 0, and so a NaN is a maximally
> inexact
number: it could be any real number or even +inf or -inf.


On 6/22/07, Thomas Lord <lord at emf.net> wrote:
>
> That's wrong.  NaN is not an interval.
>
> All normal floating point numbers are intervals.

That's wrong (and a common misconception).  All normal floating point numbers
are exact rational numbers.  While it is true that there are intervals
on the real
number line where every real in the interval maps to the same floating
point number,
the floating point number itself is just a rational.


-- 
~jrm