Safe Haskell	None
Language	Haskell2010

Control.Effect.Type.Fix

Contents

Effects
Threading utilities

Synopsis

newtype Fix :: Effect where
- Fix :: (a -> m a) -> Fix m a
threadFixViaClass :: Monad m => (RepresentationalT t, forall b. MonadFix b => MonadFix (t b)) => (forall x. Fix m x -> m x) -> Fix (t m) a -> t m a

Effects

newtype Fix :: Effect where Source #

An effect corresponding to the MonadFix type class.

Effly's MonadFix instance is based on this effect; by having access to Fix, you're able to use recursive do notation inside of effect handlers.

Fix 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 Fix instance (if possible). threadFixViaClass can help you with that.

The following threading constraints accept Fix:

Constructors

Fix :: (a -> m a) -> Fix m a

Instances

Instances details

ThreadsEff (ExceptT e) Fix Source #
Instance details Defined in Control.Effect.Type.Fix Methods threadEff :: Monad m => (forall x. Fix m x -> m x) -> Fix (ExceptT e m) a -> ExceptT e m a Source #
Monoid s => ThreadsEff (WriterT s) Fix Source #
Instance details Defined in Control.Effect.Type.Fix Methods threadEff :: Monad m => (forall x. Fix m x -> m x) -> Fix (WriterT s m) a -> WriterT s m a Source #
ThreadsEff (StateT s) Fix Source #
Instance details Defined in Control.Effect.Type.Fix Methods threadEff :: Monad m => (forall x. Fix m x -> m x) -> Fix (StateT s m) a -> StateT s m a Source #
ThreadsEff (ReaderT i) Fix Source #
Instance details Defined in Control.Effect.Type.Fix Methods threadEff :: Monad m => (forall x. Fix m x -> m x) -> Fix (ReaderT i m) a -> ReaderT i m a Source #
ThreadsEff (StateT s) Fix Source #
Instance details Defined in Control.Effect.Type.Fix Methods threadEff :: Monad m => (forall x. Fix m x -> m x) -> Fix (StateT s m) a -> StateT s m a Source #
Monoid s => ThreadsEff (WriterT s) Fix Source #
Instance details Defined in Control.Effect.Type.Fix Methods threadEff :: Monad m => (forall x. Fix m x -> m x) -> Fix (WriterT s m) a -> WriterT s m a Source #
ThreadsEff (WriterT s) Fix Source #
Instance details Defined in Control.Effect.Type.Fix Methods threadEff :: Monad m => (forall x. Fix m x -> m x) -> Fix (WriterT s m) a -> WriterT s m a Source #
(Reifies s (ReifiedEffAlgebra Fix m), Monad m) => MonadFix (ViaAlg s Fix m) Source #
Instance details Defined in Control.Effect.Type.Fix Methods mfix :: (a -> ViaAlg s Fix m a) -> ViaAlg s Fix m a #

Threading utilities

threadFixViaClass :: Monad m => (RepresentationalT t, forall b. MonadFix b => MonadFix (t b)) => (forall x. Fix m x -> m x) -> Fix (t m) a -> t m a Source #

A valid definition of threadEff for a ThreadsEff t Fix instance, given that t lifts MonadFix.