# big rationals question

**Jon Cast
**
jcast@ou.edu

*Sun, 16 Feb 2003 01:07:17 -0600*

"Damien R. Sullivan" <dasulliv@cs.indiana.edu> wrote:
<snip>
>* Then I moved to Haskell, largely rewriting the ML code. The result is
*>* much nicer looking, being able to say 'sum + powx' instead of
*>* 'Num.add_num sum powx', or having to define 'num_2' for a bignum
*>* version of 2. It took longer to actually run properly -- I got bit by
*>* laziness, but John Meacham tipped me off. And now I have
*>* '34283788463231218 % 20536892788086675' being printed out, although I
*>* seem to have a bug since if that's a numerator and denominator the
*>* result is not the natural logarithm of 2. But my real question is can
*>* I get Haskell to actually do that division itself? I get complaints
*>* about 'Fractional Integer'; I had to use bc to do the division.
*
Sure:
>* rationalToDouble :: Rational -> Double
*>* rationalToDouble rat = fromInteger (numerator rat)
*>* / fromInteger (denominator rat)
*
HTH
>* -xx- Damien X-)
*
Jon Cast