Control.Effects

Documentation

type family EffectMsg eff :: *

Instances

type EffectMsg (Early a)

type EffectMsg (Early a) = a

type EffectMsg (ReadEnv e)

type EffectMsg (ReadEnv e) = ()

type family EffectRes eff :: *

Instances

type EffectRes (Early a)

type EffectRes (Early a) = Void

type EffectRes (ReadEnv e)

type EffectRes (ReadEnv e) = e

class Monad m => MonadEffect eff m where

Minimal complete definition

effect

Methods

effect :: proxy eff -> EffectMsg eff -> m (EffectRes eff)

Use the effect described by eff.

Instances

(MonadEffect eff m, MonadTrans t, Monad (t m)) => MonadEffect eff (t m)

Methods

effect :: proxy eff -> EffectMsg eff -> t m (EffectRes eff)

Monad m => MonadEffect eff (EffectHandler eff m)

Methods

effect :: proxy eff -> EffectMsg eff -> EffectHandler eff m (EffectRes eff)

(Monad m, (~) * a b) => MonadEffect (Early a) (ExceptT (Early b) m)

Methods

effect :: proxy (Early a) -> EffectMsg (Early a) -> ExceptT (Early b) m (EffectRes (Early a))

newtype EffectHandler eff m a

The EffectHandler is really just a ReaderT carrying around the function that knows how to handle the effect.

Constructors

EffectHandler

Fields

• unpackEffectHandler :: ReaderT (EffectMsg eff -> m (EffectRes eff)) m a

Instances

MonadBase b m => MonadBase b (EffectHandler eff m)

Methods

liftBase :: b α -> EffectHandler eff m α

MonadBaseControl b m => MonadBaseControl b (EffectHandler eff m)

Associated Types

type StM (EffectHandler eff m :: * -> *) a :: *

Methods

liftBaseWith :: (RunInBase (EffectHandler eff m) b -> b a) -> EffectHandler eff m a

restoreM :: StM (EffectHandler eff m) a -> EffectHandler eff m a

MonadReader s m => MonadReader s (EffectHandler eff m)

Methods

ask :: EffectHandler eff m s

local :: (s -> s) -> EffectHandler eff m a -> EffectHandler eff m a

reader :: (s -> a) -> EffectHandler eff m a

MonadState s m => MonadState s (EffectHandler eff m)

Methods

get :: EffectHandler eff m s

put :: s -> EffectHandler eff m ()

state :: (s -> (a, s)) -> EffectHandler eff m a

Monad m => MonadEffect eff (EffectHandler eff m)

Methods

effect :: proxy eff -> EffectMsg eff -> EffectHandler eff m (EffectRes eff)

MonadTrans (EffectHandler eff)

Methods

lift :: Monad m => m a -> EffectHandler eff m a

RunnableTrans (EffectHandler eff)

Associated Types

type TransformerState (EffectHandler eff :: (* -> *) -> * -> *) (m :: * -> *) :: *

type TransformerResult (EffectHandler eff :: (* -> *) -> * -> *) (m :: * -> *) a :: *

Methods

currentTransState :: Monad m => EffectHandler eff m (TransformerState (EffectHandler eff) m)

restoreTransState :: Monad m => TransformerResult (EffectHandler eff) m a -> EffectHandler eff m a

runTransformer :: Monad m => EffectHandler eff m a -> TransformerState (EffectHandler eff) m -> m (TransformerResult (EffectHandler eff) m a)

Monad m => Monad (EffectHandler eff m)

Methods

(>>=) :: EffectHandler eff m a -> (a -> EffectHandler eff m b) -> EffectHandler eff m b

(>>) :: EffectHandler eff m a -> EffectHandler eff m b -> EffectHandler eff m b

return :: a -> EffectHandler eff m a

fail :: String -> EffectHandler eff m a

Functor m => Functor (EffectHandler eff m)

Methods

fmap :: (a -> b) -> EffectHandler eff m a -> EffectHandler eff m b

(<$) :: a -> EffectHandler eff m b -> EffectHandler eff m a

Applicative m => Applicative (EffectHandler eff m)

Methods

pure :: a -> EffectHandler eff m a

(<*>) :: EffectHandler eff m (a -> b) -> EffectHandler eff m a -> EffectHandler eff m b

(*>) :: EffectHandler eff m a -> EffectHandler eff m b -> EffectHandler eff m b

(<*) :: EffectHandler eff m a -> EffectHandler eff m b -> EffectHandler eff m a

MonadIO m => MonadIO (EffectHandler eff m)

Methods

liftIO :: IO a -> EffectHandler eff m a

MonadRandom m => MonadRandom (EffectHandler eff m)

Methods

getRandomR :: Random a => (a, a) -> EffectHandler eff m a

getRandom :: Random a => EffectHandler eff m a

getRandomRs :: Random a => (a, a) -> EffectHandler eff m [a]

getRandoms :: Random a => EffectHandler eff m [a]

Alternative m => Alternative (EffectHandler eff m)

Methods

empty :: EffectHandler eff m a

(<|>) :: EffectHandler eff m a -> EffectHandler eff m a -> EffectHandler eff m a

some :: EffectHandler eff m a -> EffectHandler eff m [a]

many :: EffectHandler eff m a -> EffectHandler eff m [a]

MonadThrow m => MonadThrow (EffectHandler eff m)

Methods

throwM :: Exception e => e -> EffectHandler eff m a

MonadCatch m => MonadCatch (EffectHandler eff m)

Methods

catch :: Exception e => EffectHandler eff m a -> (e -> EffectHandler eff m a) -> EffectHandler eff m a

type TransformerState (EffectHandler eff) m

type TransformerState (EffectHandler eff) m = EffectMsg eff -> m (EffectRes eff)

type TransformerResult (EffectHandler eff) m a

type TransformerResult (EffectHandler eff) m a = a

type StM (EffectHandler eff m) a

type StM (EffectHandler eff m) a = StM (ReaderT * (EffectMsg eff -> m (EffectRes eff)) m) a

handleEffect :: (EffectMsg eff -> m (EffectRes eff)) -> EffectHandler eff m a -> m a

Handle the effect described by eff.

module Control.Effects1