Andrew: could you explain the algebra notation you were using for short
hand? I think I followed, but for people the libraries list might be their
first exposure to advanced / graduate abstract algebra (which winds up
being simpler than most folks expect ;) )
On Fri, Jan 31, 2020 at 4:36 PM Carter Schonwald
that actually sounds pretty sane. I think!
On Fri, Jan 31, 2020 at 3:38 PM Andrew Lelechenko < andrew.lelechenko@gmail.com> wrote:
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
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