On 8/26/11 7:24 PM, Daniel Fischer wrote:
Using that as intermediate type instead of Rational in realToFrac would allow a correct Double<-> Float (and newtypes) conversion also without rewrite rules (and should be faster than 'fromRational . toRational' for these, since it would be basically 'uncurry encodeFloat . decodeFloat').
For these issues I'd like to point out the RealToFrac class[1] for correcting the problems with the Prelude's realToFrac. The current version uses -XOverlappingInstances to provide general instances, but that's just a convenience and not strictly necessary. The only thing it actually requires is MPTCs. I've been waiting for the haskell' committee to finally get around to accepting MPTCs before suggesting the class replace the Prelude's function. [1] http://hackage.haskell.org/packages/archive/logfloat/0.12.1/doc/html/Data-Nu... -- Live well, ~wren