| module Main where | |
| import Prelude | |
| import Control.Comonad (class Comonad, class Extend, extract) | |
| import Control.Monad.Eff.Console (logShow) | |
| -- Javascript - const Functor = x => ({}) | |
| newtype Box a = Box a | |
| -- Javascript - map: f => (f(x)) | |
| instance functorBox :: Functor Box where | |
| map f (Box x) = Box (f x) | |
| -- Javascript - fold: f => f(x) | |
| instance extendBox :: Extend Box where | |
| extend f m = Box (f m) | |
| instance comonadBox :: Comonad Box where | |
| extract (Box x) = x | |
| app :: Int -> Int | |
| app n = | |
| Box n # | |
| map (\n -> n * 2) # | |
| map (\n -> n + 1) # | |
| extract | |
| main = do | |
| logShow $ app $ 10 | |
| -- 21 |