[Haskell] Literal for Infinity

[Lennart Augustsson]

The RealFloat class has a number of methods for testing
various properties of a FP number:
   isNaN :: a -> Bool
   isInfinite :: a -> Bool
   isDenormalized :: a -> Bool
   isNegativeZero :: a -> Bool
   isIEEE :: a -> Bool

If you really want to create an Infinity, I suggest 1/0,
but not all FP formats support it (IEEE754 does).

	-- Lennart


Yitzchak Gale wrote:
> While checking for floating-point overflow and
> underflow conditions, I tried to create a somewhat
> reliable cross-platform Infinity with the literal
> "1e100000".
> 
> When GHC 6.4.1 reads this literal, it goes into a
> deep trance and consumes huge amounts of
> memory. Shouldn't it immediately recognize such a
> thing as Infinity?
> 
> Is there a better way to check for Infinity?  I
> have not yet figured out how to check for NaN at
> all - because it is not equal to itself. Any
> suggestions?
> 
> BTW, I notice that Simon PJ proposed literals
> for Infinity and Nan several years ago:
> 
> http://www.haskell.org/pipermail/haskell/2001-August/007753.html
> 
> Did anything ever come out of this?
> 
> Regards,
> Yitzchak
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