Kod i raka led.
Program som skalar över alla kärnor.

type Shape = Circle Int | Rect Int Int

fn :: area Shape      => Int
      area (Circle r) =  3 * r * r
      area (Rect w h) =  w * h

fn :: report [Shape] => Int Int
      report shapes  =  (total, biggest)
        || ||map area shapes               -> areas
        || fold (acc a => acc + a) 0 areas -> total
        || fold bigger 0 areas             -> biggest

fn :: bigger Int Int => Int
      bigger a   b   =
        | a > b     = a
        | otherwise = b

fn :: describe (Int Int)        => String
      describe (total, biggest) =  "total {total}, largest {biggest}"

fn :: main => ()
      main =
        shapes = [Circle 4, Rect 3 5, Rect 20 30]
        echo (describe (report shapes))