Additive : Type -> Type
Additive A = { zero : A; plus : A -> A -> A }

additive_Integer : Additive Integer
additive_Integer = { zero = 0; plus = prim_add_Int }

sum : (A:Type) -> Additive A -> List A -> A
sum _ d (Nil _) = d.zero
sum A d (Cons _ x xs) = d.plus x (sum A d xs)

Showable : Type -> Type
Showable A = { show : A -> String }


--Compositional : Type -> Type
--Compositional A = { composOp : }