On Tue, 28 Jan 2020, Dannyu NDos wrote:
Second, I suggest to move `abs` and `signum` from `Num` to `Floating`
I can fully relate your frustration with `abs` and `signum` (and numeric type classes in Haskell altogether). But IMO breaking both in `Num` and in `Floating` at once is not a promising way to make things proper. I would rather follow the beaten track of Applicative Monad and Semigroup Monoid proposals and - as a first step - introduce a superclass (probably, borrowing the design from `semirings` package): class Semiring a where zero :: a plus :: a -> a -> a one :: a times :: a -> a -> a fromNatural :: Natural -> a class Semiring a => Num a where ... Tangible benefits in `base` include: a) instance Semiring Bool, b) a total instance Semiring Natural (in contrast to a partial instance Num Natural), c) instance Num a => Semiring (Complex a) (in contrast to instance RealFloat a => Num (Complex a)), d) newtypes Sum and Product would require only Semiring constraint instead of Num. Best regards, Andrew