mirror of
https://github.com/unisonweb/unison.git
synced 2024-10-26 11:07:48 +03:00
31 lines
741 B
Plaintext
31 lines
741 B
Plaintext
--map/traverse
|
|
structural ability Noop where
|
|
noop : ∀ a . a -> {Noop} a
|
|
|
|
structural ability Noop2 where
|
|
noop2 : ∀ a . a -> a -> {Noop2} a
|
|
|
|
structural type List a = Nil | Cons a (List a)
|
|
|
|
map : ∀ a b e . (a -> {e} b) -> List a -> {e} (List b)
|
|
map f = cases
|
|
List.Nil -> List.Nil
|
|
List.Cons h t -> List.Cons (f h) (map f t)
|
|
|
|
c = List.Cons
|
|
z : ∀ a . List a
|
|
z = List.Nil
|
|
|
|
ex = (c 1 (c 2 (c 3 z)))
|
|
|
|
pureMap : List Text
|
|
pureMap = map (a -> "hello") ex
|
|
|
|
-- `map` is ability polymorphic
|
|
zappy : () -> {Noop} (List Nat)
|
|
zappy u = map (zap -> (Noop.noop (zap Nat.+ 1))) ex
|
|
|
|
-- mixing multiple abilitys in a call to `map` works fine
|
|
zappy2 : () -> {Noop, Noop2} (List Nat)
|
|
zappy2 u = map (zap -> Noop.noop (zap Nat.+ Noop2.noop2 2 7)) ex
|