Moduleeffectful-core-2.7.1.2GHC2021

Effectful.State.Dynamic

The dynamically dispatched variant of the State effect.

Note: unless you plan to change interpretations at runtime or you need the Control.Monad.State.MonadState instance for compatibility with existing code, it's recommended to use one of the statically dispatched variants, i.e. Effectful.State.Static.Local or Effectful.State.Static.Shared.

1 type
13 values

Packageeffectful-core-2.7.1.2
Exports14
LanguageGHC2021
LicenceBSD-3-Clause
SourceDynamic.hs

Effect

1 declaration

datadata State s (a :: Type -> Type) b where

Provide access to a mutable value of type s.

Constructors

Get :: State s a s
Put :: s -> State s a ()
State :: (s -> (a, s)) -> State s a b
StateM :: (s -> m (a, s)) -> State s a b

Instances1DispatchOf

type DispatchOf (State s) = 'DynamicDefined in effectful-core-2.7.1.2 · Effectful.Internal.Effect.Dynamic

Handlers

Local

valuerunStateLocal :: HasCallStack => s -> Eff (State s ': es) a -> Eff es (a, s)

Run the State effect with the given initial state and return the final value along with the final state (via Effectful.State.Static.Local).

valueevalStateLocal :: HasCallStack => s -> Eff (State s ': es) a -> Eff es a

Run the State effect with the given initial state and return the final value, discarding the final state (via Effectful.State.Static.Local).

valueexecStateLocal :: HasCallStack => s -> Eff (State s ': es) a -> Eff es s

Run the State effect with the given initial state and return the final state, discarding the final value (via Effectful.State.Static.Local).

Shared

valuerunStateShared

:: HasCallStack
=> s
-> Eff (State s ': es) a
-> Eff es (a, s)

Run the State effect with the given initial state and return the final value along with the final state (via Effectful.State.Static.Shared).

valueevalStateShared :: HasCallStack => s -> Eff (State s ': es) a -> Eff es a

Run the State effect with the given initial state and return the final value, discarding the final state (via Effectful.State.Static.Shared).

valueexecStateShared :: HasCallStack => s -> Eff (State s ': es) a -> Eff es s

Run the State effect with the given initial state and return the final state, discarding the final value (via Effectful.State.Static.Shared).

Operations

valueget :: (HasCallStack, State s :> es) => Eff es s

Fetch the current value of the state.

valuegets :: (HasCallStack, State s :> es) => (s -> a) -> Eff es a

Get a function of the current state.

gets f ≡ f <$> get

valueput :: (HasCallStack, State s :> es) => s -> Eff es ()

Set the current state to the given value.

valuestate :: (HasCallStack, State s :> es) => (s -> (a, s)) -> Eff es a

Apply the function to the current state and return a value.

valuemodify :: (HasCallStack, State s :> es) => (s -> s) -> Eff es ()

Apply the function to the current state.

modify f ≡ state (\s -> ((), f s))

valuestateM :: (HasCallStack, State s :> es) => (s -> Eff es (a, s)) -> Eff es a

Deprecated. Use a combination of get and put instead.

Apply the monadic function to the current state and return a value.

valuemodifyM :: (HasCallStack, State s :> es) => (s -> Eff es s) -> Eff es ()

Deprecated. Use a combination of get and put instead.

Apply the monadic function to the current state.

modifyM f ≡ stateM (\s -> ((), ) <$> f s)