-- | Relative monads over scopes, and 'liftRM' for renaming with them.
module Control.Monad.Foil.Relative (
  RelMonad (..),
  liftRM,
) where

import           Control.Monad.Foil
import           Control.Monad.Foil.Internal (RelMonad (..))

-- | Relative version of @liftM@ (an 'fmap' restricted to 'Monad').
--
-- @since 0.0.3
liftRM :: (RelMonad f m, Distinct b) => Scope b -> (f a -> f b) -> m a -> m b
liftRM :: forall (f :: S -> *) (m :: S -> *) (b :: S) (a :: S).
(RelMonad f m, Distinct b) =>
Scope b -> (f a -> f b) -> m a -> m b
liftRM Scope b
scope f a -> f b
f m a
m = Scope b -> m a -> (f a -> m b) -> m b
forall (b :: S) (a :: S).
Distinct b =>
Scope b -> m a -> (f a -> m b) -> m b
forall (f :: S -> *) (m :: S -> *) (b :: S) (a :: S).
(RelMonad f m, Distinct b) =>
Scope b -> m a -> (f a -> m b) -> m b
rbind Scope b
scope m a
m (f b -> m b
forall (a :: S). f a -> m a
forall (f :: S -> *) (m :: S -> *) (a :: S).
RelMonad f m =>
f a -> m a
rreturn (f b -> m b) -> (f a -> f b) -> f a -> m b
forall b c a. (b -> c) -> (a -> b) -> a -> c
. f a -> f b
f)