Modulefused-effects-1.1.2.7Haskell2010

Control.Carrier.State.Strict

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.

1 type
3 values

Packagefused-effects-1.1.2.7
Exports4
LanguageHaskell2010
LicenceBSD-3-Clause
SourceStrict.hs

Strict state carrier

4 declarations

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

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, ())

valueevalState :: Functor m => s -> StateC s m a -> m a

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

evalState s m = fmap snd (runState s m)

valueexecState :: Functor m => s -> StateC s m a -> m s

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

execState s m = fmap fst (runState s m)

newtypenewtype StateC s (m :: Type -> Type) a

Constructors

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

Instances10MonadTrans, Monad, Functor, MonadFix, MonadFail, Applicative, …

MonadTrans (StateC s)Defined in fused-effects-1.1.2.7 · Control.Carrier.State.Strict
Monad m => Monad (StateC s m)Defined in fused-effects-1.1.2.7 · Control.Carrier.State.Strict
Functor m => Functor (StateC s m)Defined in fused-effects-1.1.2.7 · Control.Carrier.State.Strict
MonadFix m => MonadFix (StateC s m)Defined in fused-effects-1.1.2.7 · Control.Carrier.State.Strict
MonadFail m => MonadFail (StateC s m)Defined in fused-effects-1.1.2.7 · Control.Carrier.State.Strict
Monad m => Applicative (StateC s m)Defined in fused-effects-1.1.2.7 · Control.Carrier.State.Strict
(Alternative m, Monad m) => Alternative (StateC s m)Defined in fused-effects-1.1.2.7 · Control.Carrier.State.Strict
(Alternative m, Monad m) => MonadPlus (StateC s m)Defined in fused-effects-1.1.2.7 · Control.Carrier.State.Strict
MonadIO m => MonadIO (StateC s m)Defined in fused-effects-1.1.2.7 · Control.Carrier.State.Strict
Algebra sig m => Algebra (State s :+: sig) (StateC s m)Defined in fused-effects-1.1.2.7 · Control.Carrier.State.Strict

State effect

0 declarations

module Control.Effect.State