Moduleeffectful-core-2.7.1.2GHC2021

Effectful.Labeled.State

Convenience functions for the Labeled State effect.

2 types
13 values

Packageeffectful-core-2.7.1.2
Exports15
LanguageGHC2021
LicenceBSD-3-Clause
SourceState.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
The initial state.
-> Eff (Labeled label (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
The initial state.
-> Eff (Labeled label (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
The initial state.
-> Eff (Labeled label (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
The initial state.
-> Eff (Labeled label (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
The initial state.
-> Eff (Labeled label (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
The initial state.
-> Eff (Labeled label (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, Labeled label (State s) :> es) => Eff es s

Fetch the current value of the state.

valuegets

:: (HasCallStack, Labeled label (State s) :> es)
=> (s -> a)
.
-> Eff es a

Get a function of the current state.

gets f ≡ f <$> get

valueput

:: (HasCallStack, Labeled label (State s) :> es)
=> s
.
-> Eff es ()

Set the current state to the given value.

valuestate

:: (HasCallStack, Labeled label (State s) :> es)
=> (s -> (a, s))
.
-> Eff es a

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

valuemodify

:: (HasCallStack, Labeled label (State s) :> es)
=> (s -> s)
.
-> Eff es ()

Apply the function to the current state.

modify f ≡ state (\s -> ((), f s))

valuestateM

:: (HasCallStack, Labeled label (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, Labeled label (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)

Re-exports

1 declaration

newtypenewtype Labeled (label :: k) (e :: Effect) (a :: Type -> Type) b where

Assign a label to an effect.

Note: labeled effects are best used together with the effectful-plugin package, as it significantly improves their usability.

The constructor is for sending labeled operations of a dynamically dispatched effect to the handler:

Example1 expression

>>> import Effectful.Dispatch.Dynamic

Example1 expression

>>> :{  data X :: Effect where    X :: X m Int  type instance DispatchOf X = Dynamic:}

Example1 expression

>>> :{  runPureEff . runLabeled @"x" (interpret_ $ \X -> pure 333) $ do    send $ Labeled @"x" X:}333

Constructors

Labeled :: e m a -> Labeled label e a b

Instances2DispatchOf, StaticRep

type DispatchOf (Labeled label e) = DispatchOf eDefined in effectful-core-2.7.1.2 · Effectful.Labeled
data StaticRep (Labeled label e)Defined in effectful-core-2.7.1.2 · Effectful.Labeled