Mokhov2.hs

data Mokhov2 f g a where
    Mokhov2 :: (x -> Either a (y -> a)) -> f x -> g y -> Mokhov2 f g a

toMokhov2 :: Mokhov f g a -> Mokhov2 f g a
toMokhov2 (x :<*?: y) = Mokhov2 f y x where
    f ::  (x -> a) -> Either a (Either x a -> a)
    f xa = Right $ either xa id

fromMokhov2 :: (Functor f, Functor g) => Mokhov2 f g a -> Mokhov f g a
fromMokhov2 (Mokhov2 f x y) =
    fmap Left y
    :<*?:
    fmap (\x' y' -> either id ($ y') (f x')) x