Remove Effectful.Internal.MTL module

effectful-core/effectful-core.cabal

@@ -92,7 +92,6 @@ library
                      Effectful.Fail
                      Effectful.Internal.Effect
                      Effectful.Internal.Env
-                     Effectful.Internal.MTL
                      Effectful.Internal.Monad
                      Effectful.Internal.Unlift
                      Effectful.Internal.Utils

effectful-core/src/Effectful.hs

@@ -64,7 +64,6 @@ import Control.Monad.IO.Unlift
 
 import Effectful.Internal.Effect
 import Effectful.Internal.Env
-import Effectful.Internal.MTL ()
 import Effectful.Internal.Monad
 
 -- $intro

effectful-core/src/Effectful/Error/Dynamic.hs

@@ -34,7 +34,7 @@ import GHC.Stack (withFrozenCallStack)
 import Effectful
 import Effectful.Dispatch.Dynamic
 import Effectful.Error.Static qualified as E
-import Effectful.Internal.MTL (Error(..))
+import Effectful.Internal.Monad (Error(..))
 
 -- | Handle errors of type @e@ (via "Effectful.Error.Static").
 runError

effectful-core/src/Effectful/Internal/Monad.hs

@@ -30,6 +30,18 @@ module Effectful.Internal.Monad
   , PrimStateEff
   , runPrim
 
+  -- * Error
+  , Error(..)
+
+  -- * Reader
+  , Reader(..)
+
+  -- * State
+  , State(..)
+
+  -- * Writer
+  , Writer(..)
+
   -- * Lifting
   , raise
   , raiseWith
@@ -83,11 +95,15 @@ import Control.Exception qualified as E
 import Control.Monad
 import Control.Monad.Base
 import Control.Monad.Catch qualified as C
+import Control.Monad.Except qualified as MTL
 import Control.Monad.Fix
 import Control.Monad.IO.Class
 import Control.Monad.IO.Unlift
 import Control.Monad.Primitive
+import Control.Monad.Reader qualified as MTL
+import Control.Monad.State qualified as MTL
 import Control.Monad.Trans.Control
+import Control.Monad.Writer qualified as MTL
 import Data.Kind (Constraint)
 import GHC.Exts (oneShot)
 import GHC.IO (IO(..))
@@ -472,6 +488,86 @@ instance Prim :> es => PrimMonad (Eff es) where
   type PrimState (Eff es) = PrimStateEff
   primitive = unsafeEff_ . IO . unsafeCoerce
 
+----------------------------------------
+-- Error
+
+-- | Provide the ability to handle errors of type @e@.
+data Error e :: Effect where
+  -- | @since 2.4.0.0
+  ThrowErrorWith :: (e -> String) -> e -> Error e m a
+  CatchError :: m a -> (CallStack -> e -> m a) -> Error e m a
+
+type instance DispatchOf (Error e) = Dynamic
+
+-- | Instance included for compatibility with existing code.
+instance
+  ( Show e
+  , Error e :> es
+  , MTL.MonadError e (Eff es)
+  ) => MTL.MonadError e (Eff es) where
+  throwError = send . ThrowErrorWith show
+  catchError action = send . CatchError action . const
+
+----------------------------------------
+-- Reader
+
+data Reader r :: Effect where
+  Ask   :: Reader r m r
+  Local :: (r -> r) -> m a -> Reader r m a
+
+type instance DispatchOf (Reader r) = Dynamic
+
+-- | Instance included for compatibility with existing code.
+instance
+  ( Reader r :> es
+  , MTL.MonadReader r (Eff es)
+  ) => MTL.MonadReader r (Eff es) where
+  ask = send Ask
+  local f = send . Local f
+  reader f = f <$> send Ask
+
+----------------------------------------
+-- State
+
+-- | Provide access to a mutable value of type @s@.
+data State s :: Effect where
+  Get    :: State s m s
+  Put    :: s -> State s m ()
+  State  :: (s ->   (a, s)) -> State s m a
+  StateM :: (s -> m (a, s)) -> State s m a
+
+type instance DispatchOf (State s) = Dynamic
+
+-- | Instance included for compatibility with existing code.
+instance
+  ( State s :> es
+  , MTL.MonadState s (Eff es)
+  ) => MTL.MonadState s (Eff es) where
+  get = send Get
+  put = send . Put
+  state = send . State
+
+----------------------------------------
+-- Writer
+
+-- | Provide access to a write only value of type @w@.
+data Writer w :: Effect where
+  Tell   :: w   -> Writer w m ()
+  Listen :: m a -> Writer w m (a, w)
+
+type instance DispatchOf (Writer w) = Dynamic
+
+-- | Instance included for compatibility with existing code.
+instance
+  ( Monoid w
+  , Writer w :> es
+  , MTL.MonadWriter w (Eff es)
+  ) => MTL.MonadWriter w (Eff es) where
+  writer (a, w) = a <$ send (Tell w)
+  tell = send . Tell
+  listen = send . Listen
+  pass = error "pass is not implemented due to ambiguous semantics in presence of runtime exceptions"
+
 ----------------------------------------
 -- Lifting
 

effectful-core/src/Effectful/Reader/Dynamic.hs

@@ -20,7 +20,7 @@ module Effectful.Reader.Dynamic
 
 import Effectful
 import Effectful.Dispatch.Dynamic
-import Effectful.Internal.MTL (Reader(..))
+import Effectful.Internal.Monad (Reader(..))
 
 -- | Run the 'Reader' effect with the given initial environment.
 runReader

effectful-core/src/Effectful/State/Dynamic.hs

@@ -32,7 +32,7 @@ module Effectful.State.Dynamic
 
 import Effectful
 import Effectful.Dispatch.Dynamic
-import Effectful.Internal.MTL (State(..))
+import Effectful.Internal.Monad (State(..))
 import Effectful.State.Static.Local qualified as L
 import Effectful.State.Static.Shared qualified as S
 

effectful-core/src/Effectful/Writer/Dynamic.hs

@@ -27,7 +27,7 @@ module Effectful.Writer.Dynamic
 
 import Effectful
 import Effectful.Dispatch.Dynamic
-import Effectful.Internal.MTL (Writer(..))
+import Effectful.Internal.Monad (Writer(..))
 import Effectful.Writer.Static.Local qualified as L
 import Effectful.Writer.Static.Shared qualified as S