{-# LANGUAGE Arrows #-}

foo0 f g x y = proc _ -> (| f (g -< (x, y)) |)

foo1 f g h x =
  proc (y, z) -> (|
    test ( h f
             . h g
             -<
           y x
             . y z
         )
         ( h g
             . h f
             -<
           y z
             . y x)
  |)