[racket] Value Formatting ~r Routine and Non-Rational +nan.0

The contract for '~r' deliberately excludes +nan.0, +inf.0, etc---that's 
why it's 'rational?' and not 'real?'. The point of '~r' is to provide 
numeric formatting options, none of which apply to +nan.0, etc.

Ryan


On 03/04/2013 01:26 PM, Ray Racine wrote:
> Currently  the `~r' format routine, which accepts rationals, barfs on
> +nan.0 and siblings, which are not rationals.  My current use case is
> simply displaying sub-ranges of vectors of flonums.  It is not a problem
> to check for +nan.0 and explicitly display it. I was just wanted to toss
> it out as a don't know what is the "right thing" for the `~r' format
> routine to do here.
>
>  > (define: x : Flonum +nan.0)
>  > (define: y : Flonum 3.145962)
>  > (~r y)
> - : String
> "3.145962"
>  > (~r x)
> ~r: contract violation
>   expected: rational?
>   given: +nan.0
> ...
>
>
>
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