profunctor

Profunctor instance for function type.

Values

function_profunctor

pub fn function_profunctor(
  ,
) -> profunctor.Profunctor(
  types.ArrowPro,
  a,
  b,
  c,
  d,
  fn(b) -> c,
  fn(a) -> d,
)

Profunctor instance for the function type (->).

// Haskell implementation
instance Profunctor (->) where
  dimap ab cd bc = cd ∘ bc ∘ ab
  lmap = flip (∘)
  rmap = (∘)

Examples

// Function a -> b ([Int] -> Int)
let f = list.fold(_, 0, fn(x, y) { x + y })
// Function c -> d (Bool -> String)
let g = bool.to_string
// Profunctor pbc: Function b -> c (Int -> Bool)
let h = fn(x) { x % 2 == 0 }
// Profunctor pad: Function a -> d ([Int] -> String)
let z = function_profunctor().dimap(f, g)(h)
[1, 2, 3]
|> z
// -> "True"
[1, 2]
|> z
// -> "False"