Safe Haskell	Safe-Inferred
Language	Haskell2010

Control.Carrier.State.Strict

Contents

Strict state carrier
State effect

Description

A carrier for the State effect. It evaluates its inner state strictly, which is the correct choice for the majority of use cases.

Note that the parameter order in runState, evalState, and execState is reversed compared the equivalent functions provided by transformers. This is an intentional decision made to enable the composition of effect handlers with . without invoking flip.

Since: 1.0.0.0

Synopsis

runState :: s -> StateC s m a -> m (s, a)
evalState :: forall s m a. Functor m => s -> StateC s m a -> m a
execState :: forall s m a. Functor m => s -> StateC s m a -> m s
newtype StateC s m a = StateC (s -> m (s, a))
module Control.Effect.State

Strict state carrier

runState :: s -> StateC s m a -> m (s, a) Source #

Run a State effect starting from the passed value.

runState s (pure a) = pure (s, a)

runState s get = pure (s, s)

runState s (put t) = pure (t, ())

Since: 1.0.0.0

evalState :: forall s m a. Functor m => s -> StateC s m a -> m a Source #

Run a State effect, yielding the result value and discarding the final state.

evalState s m = fmap snd (runState s m)

Since: 1.0.0.0

execState :: forall s m a. Functor m => s -> StateC s m a -> m s Source #

Run a State effect, yielding the final state and discarding the return value.

execState s m = fmap fst (runState s m)

Since: 1.0.0.0

newtype StateC s m a Source #

Since: 1.0.0.0

Constructors

StateC (s -> m (s, a))

Instances

Instances details

MonadTrans (StateC s) Source #
Instance details Defined in Control.Carrier.State.Strict Methods lift :: Monad m => m a -> StateC s m a #
MonadFail m => MonadFail (StateC s m) Source #
Instance details Defined in Control.Carrier.State.Strict Methods fail :: String -> StateC s m a #
MonadFix m => MonadFix (StateC s m) Source #
Instance details Defined in Control.Carrier.State.Strict Methods mfix :: (a -> StateC s m a) -> StateC s m a #
MonadIO m => MonadIO (StateC s m) Source #
Instance details Defined in Control.Carrier.State.Strict Methods liftIO :: IO a -> StateC s m a #
(Alternative m, Monad m) => Alternative (StateC s m) Source #
Instance details Defined in Control.Carrier.State.Strict Methods empty :: StateC s m a # (<\|>) :: StateC s m a -> StateC s m a -> StateC s m a # some :: StateC s m a -> StateC s m [a] # many :: StateC s m a -> StateC s m [a] #
Monad m => Applicative (StateC s m) Source #
Instance details Defined in Control.Carrier.State.Strict Methods pure :: a -> StateC s m a # (<>) :: StateC s m (a -> b) -> StateC s m a -> StateC s m b # liftA2 :: (a -> b -> c) -> StateC s m a -> StateC s m b -> StateC s m c # (>) :: StateC s m a -> StateC s m b -> StateC s m b # (<*) :: StateC s m a -> StateC s m b -> StateC s m a #
Functor m => Functor (StateC s m) Source #
Instance details Defined in Control.Carrier.State.Strict Methods fmap :: (a -> b) -> StateC s m a -> StateC s m b # (<$) :: a -> StateC s m b -> StateC s m a #
Monad m => Monad (StateC s m) Source #
Instance details Defined in Control.Carrier.State.Strict Methods (>>=) :: StateC s m a -> (a -> StateC s m b) -> StateC s m b # (>>) :: StateC s m a -> StateC s m b -> StateC s m b # return :: a -> StateC s m a #
(Alternative m, Monad m) => MonadPlus (StateC s m) Source #
Instance details Defined in Control.Carrier.State.Strict Methods mzero :: StateC s m a # mplus :: StateC s m a -> StateC s m a -> StateC s m a #
Algebra sig m => Algebra (State s :+: sig) (StateC s m) Source #
Instance details Defined in Control.Carrier.State.Strict Methods alg :: forall ctx (n :: Type -> Type) a. Functor ctx => Handler ctx n (StateC s m) -> (State s :+: sig) n a -> ctx () -> StateC s m (ctx a) Source #

State effect

module Control.Effect.State