On Fri, 8 Dec 2006, Dan Weston wrote: > 1) Groups may only want to define addition. Why can't they use + > (instead of <+>, >++++?&**+>, or other such perversion)?
http://darcs.haskell.org/numericprelude/src/Algebra/Monoid.hs > 2) Affine spaces have a (-) but no (+). Worse, the signature might be > (-) :: Point -> Point -> Vector, which doesn't unify with (a -> a -> a). yet to come > 3) Quaternions have no signum, unit quaternions have (*), (/) but no (+) > or (-), abs would have a different signatures (Quaternion -> Double) > which doesn't unify with (a -> a), and fields cannot be scaled with (*) > as in (*) :: (Field f) => Double -> f -> f http://darcs.haskell.org/numericprelude/src/Number/Quaternion.hs -> norm _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
