purescript-0.5.4.1: examples/passing/Church.purs

module Main where

  import Prelude ()

  type List a = forall r. r -> (a -> r -> r) -> r

  empty :: forall a. List a
  empty = \r f -> r

  cons :: forall a. a -> List a -> List a
  cons = \a l r f -> f a (l r f)

  append :: forall a. List a -> List a -> List a
  append = \l1 l2 r f -> l2 (l1 r f) f

  test = append (cons 1 empty) (cons 2 empty)

  main = Debug.Trace.trace "Done"