codata

Main.purs

module Main where

import Prelude

class Codata --where

data Stream a
  = Head a (Codata => Stream a)

from :: Int -> Stream Int
from x = Head x (from (x + 1))

-- mapStream :: forall a b. (a -> b) -> Stream a -> Stream b
mapStream f (Head x xs) = Head (f x) (mapStream f xs)