{-# LANGUAGE Arrows #-}

foo x = proc a -> a -< x

foolr x = proc a -> x >- a

bar f x =
  proc
    ( y,
      z,
      w
      )
  ->
    f -- The value
      -<
        ( x, -- Foo
          w, -- Bar
          z -- Baz
        )

baz x = proc a -> a -<< x

bazlr x = proc a -> x >>- a