partition :: (a -> Boolean) -> Array a -> Pair (Array a) (Array a)

Haskell provides partition in Data.List, but it’s just one of many partition functions. Can we generalize? The first step might be to accept any Foldable:

partition :: Foldable f => (a -> Boolean) -> f a -> Pair (Array a) (Array a)

Could we go one step further by parameterizing Array in the return type? Would adding a Monoid constraint to f be sufficient?

[davidchambers]

I was imagining something like this:

> S.partition(S.odd, [1, 2, 3])
[[1, 3], [2]]

> S.partition(S.odd, Cons(1, Cons(2, Cons(3, Nil))))
[Cons(1, Cons(3, Nil)), Cons(2, Nil)]

Does this seem reasonable?

[gabejohnson]

Ahhh…we want tagBy to be exclusive.