Control.Effect.Unlift

Effects

data Unlift b m a where

A helper primitive effect for unlifting to a base monad.

Helper primitive effects are effects that allow you to avoid interpreting one of your own effects as a primitive if the power needed from direct access to the underlying monad can instead be provided by the relevant helper primitive effect. The reason why you'd want to do this is that helper primitive effects already have ThreadsEff instances defined for them, so you don't have to define any for your own effect.

The helper primitive effects offered in this library are -- in order of ascending power -- Regional, Optional, BaseControl and Unlift.

Unlift is typically used as a primitive effect. If you define a Carrier that relies on a novel non-trivial monad transformer t, then you need to make a ThreadsEff t (Unlift b) instance (if possible). threadUnliftViaClass can help you with that.

The following threading constraints accept Unlift:

• ReaderThreads

Constructors

Unlift :: forall b m a. ((forall x. m x -> b x) -> b a) -> Unlift b m a

Instances

Carrier m => PrimHandler UnliftH (Unlift m) m

Defined in Control.Effect.Internal.Unlift

Methods

effPrimHandler :: EffPrimHandler (Unlift m) m

ThreadsEff (ReaderT i) (Unlift b)

Defined in Control.Effect.Type.Unlift

Methods

threadEff :: Monad m => (forall x. Unlift b m x -> m x) -> Unlift b (ReaderT i m) a -> ReaderT i m a

Actions

unlift :: Eff (Unlift b) m => ((forall x. m x -> b x) -> b a) -> m a

Interpretations

class (MonadBaseControl b m, forall x. Pure m x) => MonadBaseControlPure b m

A constraint synonym for MonadBaseControl b m together with that StM m a ~ a for all a.

Instances

(MonadBaseControl b m, forall x. Pure m x) => MonadBaseControlPure b m

Defined in Control.Effect.Type.Unlift

unliftToFinal :: (MonadBaseControlPure b m, Carrier m) => UnliftToFinalC b m a -> m a

Run a Unlift b effect, where the unlifted monad b is the final base monad of m

Derivs (UnliftToFinalC b m) = Unlift b ': Derivs m

Prims  (UnliftToFinalC b m) = Unlift b ': Prims m

runUnlift :: Carrier m => UnliftC m a -> m a

Run a Unlift m effect, where the unlifted monad m is the current monad.

Derivs (UnliftC m) = Unlift m ': Derivs m

Prims  (UnliftC m) = Unlift m ': Prims m

Threading utilities

threadUnliftViaClass :: forall b t m a. (MonadTransControlPure t, Monad m) => (forall x. Unlift b m x -> m x) -> Unlift b (t m) a -> t m a

A valid definition of threadEff for a ThreadsEff (Unlift b) t instance, given that t is a MonadTransControl where StT t a ~ a holds for all a.

Combinators for Algebras

powerAlgUnlift :: forall m p a. Algebra' p m a -> Algebra' (Unlift m ': p) m a

Strengthen an Algebra p m by adding a Unlift m handler

powerAlgUnliftFinal :: forall b m p a. MonadBaseControlPure b m => Algebra' p m a -> Algebra' (Unlift b ': p) m a

Strengthen an Algebra p m by adding a Unlift b handler, where b is the final base monad.

Carriers

type UnliftToFinalC b = InterpretPrimC UnliftToFinalH (Unlift b)

data UnliftC m a

Instances

MonadTrans (UnliftC :: (Type -> Type) -> Type -> Type)

Defined in Control.Effect.Internal.Unlift

Methods

lift :: Monad m => m a -> UnliftC m a

MonadTransControl (UnliftC :: (Type -> Type) -> Type -> Type)

Defined in Control.Effect.Internal.Unlift

Associated Types

type StT UnliftC a :: Type

Methods

liftWith :: Monad m => (Run UnliftC -> m a) -> UnliftC m a

restoreT :: Monad m => m (StT UnliftC a) -> UnliftC m a

Monad m => Monad (UnliftC m)

Defined in Control.Effect.Internal.Unlift

Methods

(>>=) :: UnliftC m a -> (a -> UnliftC m b) -> UnliftC m b

(>>) :: UnliftC m a -> UnliftC m b -> UnliftC m b

return :: a -> UnliftC m a

fail :: String -> UnliftC m a

Functor m => Functor (UnliftC m)

Defined in Control.Effect.Internal.Unlift

Methods

fmap :: (a -> b) -> UnliftC m a -> UnliftC m b

(<$) :: a -> UnliftC m b -> UnliftC m a

MonadFix m => MonadFix (UnliftC m)

Defined in Control.Effect.Internal.Unlift

Methods

mfix :: (a -> UnliftC m a) -> UnliftC m a

MonadFail m => MonadFail (UnliftC m)

Defined in Control.Effect.Internal.Unlift

Methods

fail :: String -> UnliftC m a

Applicative m => Applicative (UnliftC m)

Defined in Control.Effect.Internal.Unlift

Methods

pure :: a -> UnliftC m a

(<*>) :: UnliftC m (a -> b) -> UnliftC m a -> UnliftC m b

liftA2 :: (a -> b -> c) -> UnliftC m a -> UnliftC m b -> UnliftC m c

(*>) :: UnliftC m a -> UnliftC m b -> UnliftC m b

(<*) :: UnliftC m a -> UnliftC m b -> UnliftC m a

MonadIO m => MonadIO (UnliftC m)

Defined in Control.Effect.Internal.Unlift

Methods

liftIO :: IO a -> UnliftC m a

Alternative m => Alternative (UnliftC m)

Defined in Control.Effect.Internal.Unlift

Methods

empty :: UnliftC m a

(<|>) :: UnliftC m a -> UnliftC m a -> UnliftC m a

some :: UnliftC m a -> UnliftC m [a]

many :: UnliftC m a -> UnliftC m [a]

MonadPlus m => MonadPlus (UnliftC m)

Defined in Control.Effect.Internal.Unlift

Methods

mzero :: UnliftC m a

mplus :: UnliftC m a -> UnliftC m a -> UnliftC m a

MonadThrow m => MonadThrow (UnliftC m)

Defined in Control.Effect.Internal.Unlift

Methods

throwM :: Exception e => e -> UnliftC m a

MonadCatch m => MonadCatch (UnliftC m)

Defined in Control.Effect.Internal.Unlift

Methods

catch :: Exception e => UnliftC m a -> (e -> UnliftC m a) -> UnliftC m a

MonadMask m => MonadMask (UnliftC m)

Defined in Control.Effect.Internal.Unlift

Methods

mask :: ((forall a. UnliftC m a -> UnliftC m a) -> UnliftC m b) -> UnliftC m b

uninterruptibleMask :: ((forall a. UnliftC m a -> UnliftC m a) -> UnliftC m b) -> UnliftC m b

generalBracket :: UnliftC m a -> (a -> ExitCase b -> UnliftC m c) -> (a -> UnliftC m b) -> UnliftC m (b, c)

Carrier m => Carrier (UnliftC m)

Defined in Control.Effect.Internal.Unlift

Associated Types

type Derivs (UnliftC m) :: [Effect]

type Prims (UnliftC m) :: [Effect]

Methods

algPrims :: Algebra' (Prims (UnliftC m)) (UnliftC m) a

reformulate :: Monad z => Reformulation' (Derivs (UnliftC m)) (Prims (UnliftC m)) (UnliftC m) z a

algDerivs :: Algebra' (Derivs (UnliftC m)) (UnliftC m) a

type StT (UnliftC :: (Type -> Type) -> Type -> Type) a

Defined in Control.Effect.Internal.Unlift

type StT (UnliftC :: (Type -> Type) -> Type -> Type) a = StT (IdentityT :: (Type -> Type) -> Type -> Type) a

type Derivs (UnliftC m)

Defined in Control.Effect.Internal.Unlift

type Derivs (UnliftC m) = Derivs (InterpretPrimC UnliftH (Unlift m) m)

type Prims (UnliftC m)

Defined in Control.Effect.Internal.Unlift

type Prims (UnliftC m) = Prims (InterpretPrimC UnliftH (Unlift m) m)