Provide access to a mutable value of type 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).

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

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

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

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

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

Fetch the current value of the state.

Get a function of the current state.

gets f ≡ f <$> get

Set the current state to the given value.

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

Apply the function to the current state.

modify f ≡ state (\s -> ((), f s))

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

Apply the monadic function to the current state.

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

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:

>>> import Effectful.Dispatch.Dynamic

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

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