On 11/2/11 7:14 AM, Eugene Kirpichov wrote:
I rewrote cFloatConv like this:
import GHC.Float class (RealFloat a, RealFloat b) => CFloatConv a b where cFloatConv :: a -> b cFloatConv = realToFrac
instance CFloatConv Double Double where cFloatConv = id instance CFloatConv Double CDouble instance CFloatConv CDouble Double instance CFloatConv Float Float where cFloatConv = id instance CFloatConv Float Double where cFloatConv = float2Double instance CFloatConv Double Float where cFloatConv = double2Float
If you're going the MPTC route, I suggest you use logfloat:Data.Number.RealToFrac[1]. I don't have the CDouble and CFloat instances, but I could add them. The instances themselves are only moderately more clever than yours ---namely using CPP for portability to non-GHC compilers--- but I think it's good for people to rally around one implementation of the solution instead of having a bunch of copies of the same thing, each poorly maintained because of the distributedness. [1] http://hackage.haskell.org/packages/archive/logfloat/0.12.1/doc/html/Data-Nu... -- Live well, ~wren