[Python-ideas] Disallow orderring comparison to NaN

[Alexander Belopolsky]

On Fri, Apr 29, 2011 at 3:30 AM, Stephen J. Turnbull <stephen at xemacs.org> wrote:
> Rob Cliffe writes:
>
>  > True.  But why be forced to walk on eggshells when writing a perfectly
>  > ordinary bit of code that "ought" to work as is?
>
> What makes you think *anything* "ought" to "work" in the  presence of
> NaNs?

There are different shades of "not working".  In most cases, raising
an exception is preferable to silently producing garbage or entering
an infinite loop.  NaNs are unordered and NaN < 0 makes as much sense
as None < 0 or "abc" < 0.  The later operations raise an exception in
py3k.