{-# LANGUAGE Arrows #-}

foo x = proc (y, z) -> do
  (|
    bar
      (bindA -< y)
    |)

foo1 x = proc (y, z) -> do
  (|
    bar
      (bindA -< y)
    |)
    z

foo2 = proc () -> do
  ( proc () ->
      returnA -< ()
    )
    -<
      ()