[Haskell-cafe] Re: Why purely in haskell?

Ketil Malde ketil+haskell at ii.uib.no
Fri Jan 11 08:10:40 EST 2008

Ketil Malde <ketil+haskell at ii.uib.no> writes:

>> The bombing of NaN *might* be a profound compilation option, but for
>> people who really do numerical work, this is a blessing NOT to have
>> it.

I'll expand a bit of this, after I've checked with Wikipedia.  Please
correct me (and it) if I'm wrong, but:

1) Intel CPUs generate exceptions, not NaNs (unless a NaN is already
   involved), so NaNs are introduced by choice in the run-time system.

2) IEE754 supports both 'signaling' and 'quiet' NaNs, so it seems the
   standard is not blessed in this regard.

And, in Haskell, I'd consider using NaNs for missing values slightly
abusive of the system, this is just a poor man's way of spelling
"Maybe Double".

If I haven't seen further, it is by standing in the footprints of giants

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