On Tue, 08 Jul 2003 13:06:23 +0100 Jon Fairbairn <[EMAIL PROTECTED]> wrote:
> On 2003-07-08 at 10:15+0200 Jerzy Karczmarczuk wrote: > > > If it's a _Rational_, surely you want it to be exactly the > > > same as you get for 31415926536%10000000000? > > > > No. If 'you' means concretely me, then no. Simply no. > > Writing > > pi = 3.1415926536 :: Rational > > > > and expecting to continue the computations with an exact fraction > > 31415926536%10000000000, with the well known explosion of Nums & > > Dens seems pragmatically silly. > > Ah, well, I'd say that writing > > pi = 3.1415926536 :: Rational > > is just misleading -- we all know jolly well that pi isn't a > rational, so anyone who writes that deserves what they get. > > Now, if you were to write > > pi = 3.1415926536 :: Real > > I'd be happy to argue over just what the conversion is > supposed to do. Unfortunately we don't have Real (in > libraries as far as I remember -- if you have a continued > fraction implementation of it, it ought to go to the > libraries list). There's an exact real library in haskell-libs using Linear Fractional Transformations, http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/haskell-libs/libs/exactreal/. _______________________________________________ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe