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 EffectMsg (SetState s)

type EffectMsg (SetState s) = s

type EffectMsg (GetState s)

type EffectMsg (GetState s) = ()

type family EffectRes eff :: *

Instances

type EffectRes (Early a)

type EffectRes (Early a) = Void

type EffectRes (ReadEnv e)

type EffectRes (ReadEnv e) = e

type EffectRes (SetState s)

type EffectRes (SetState s) = ()

type EffectRes (GetState s)

type EffectRes (GetState s) = s

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 => MonadEffect (Early a) (ExceptT a m)

Methods

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

Monad m => MonadEffect (SetState s) (StateT s m)

Methods

effect :: proxy (SetState s) -> EffectMsg (SetState s) -> StateT s m (EffectRes (SetState s))

Monad m => MonadEffect (GetState s) (StateT s m)

Methods

effect :: proxy (GetState s) -> EffectMsg (GetState s) -> StateT s m (EffectRes (GetState s))

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

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

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

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

Associated Types

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

Methods

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

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

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

Methods

liftBase :: IO α -> EffectHandler eff m α

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

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

MonadRandom m => MonadRandom (EffectHandler eff m)

Methods

getRandom :: Random a => EffectHandler eff m a

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

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

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

MonadIO m => MonadIO (EffectHandler eff m)

Methods

liftIO :: IO 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 StM (EffectHandler eff m) a

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

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

Handle the effect described by eff.

module Control.Effects1