[Python-ideas] Disallow orderring comparison to NaN

[Robert Kern]

On 4/28/11 12:00 PM, Alexander Belopolsky wrote:
> On Thu, Apr 28, 2011 at 12:46 PM, Robert Kern<robert.kern at gmail.com>  wrote:
> ..
>> Python uses the<  operator for sorting, not a comparison function, so it's
>> current behavior is perfectly in line with the IEEE-754 spec.
>
> No, it is not.  As I explained in the previous post, IEEE-754
> prescribes different behavior for<,>,<=, and>= operations and !=
> and ==.  The former signal INVALID exception while the later don't.
> Python does not make this distinction.

But it also states that such signals should *not* trap by default. The only 
thing I can really fault Python for, compliance-wise, is that it will hide the 
FPE from being handled in user code because of the 
PyFPE_START_PROTECT/PyFPE_END_PROTECT macros that surround the actual C 
operation. The only way to get the FPE to handle it is to build and install 
fpectl, which is officially discouraged.

-- 
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless enigma
  that is made terrible by our own mad attempt to interpret it as though it had
  an underlying truth."
   -- Umberto Eco