[Haskell-cafe] Arbitrary precision?

[Stefan O'Rear]

On Sun, May 06, 2007 at 05:15:08PM +0100, Andrew Coppin wrote:
> Greetings.
> 
> Haskell has arbitrary precision integers, in the form of the Integer 
> type. Is there a type somewhere that implements arbitrary precision 
> fractional values?

Yes, Rational in the Prelude (with extra functions in Ratio)

Prelude> let fibs = (1::Rational) : 1 : zipWith (+) fibs (tail fibs)
Prelude> let grs = zipWith (/) (tail fibs) fibs
Prelude> take 10 grs
[1%1,2%1,3%2,5%3,8%5,13%8,21%13,34%21,55%34,89%55]
Prelude> take 10 (zipWith (-) grs (tail grs))
[(-1)%1,1%2,(-1)%6,1%15,(-1)%40,1%104,(-1)%273,1%714,(-1)%1870,1%4895]
Prelude>