Effect

Assign a label to an effect.

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

Run a Labeled effect with a given effect handler.

Bring an effect into scope without a label.

Useful for running code written with the non-labeled effect in mind.