Modulepolysemy-1.9.2.0Haskell2010

Polysemy.Internal.Writer

datadata Writer o (m :: Type -> Type) a where

An effect capable of emitting and intercepting messages.

Tell :: o -> Writer o m ()
Write a message to the log.
Listen :: m a -> Writer o m a
Return the log produced by the higher-order action.
Pass :: m (o -> o, a) -> Writer o m a
Run the given action and apply the function it returns to the log.

valuetell :: Member (Writer o) r => o -> Sem r ()

Write a message to the log.

valuelisten :: Member (Writer o) r => Sem r a -> Sem r (o, a)

Return the log produced by the higher-order action.

valuepass :: Member (Writer o) r => Sem r (o -> o, a) -> Sem r a

Run the given action and apply the function it returns to the log.

valuewriterToEndoWriter

Transform a Writer o effect into a Writer (Endo o) effect, right-associating all uses of <> for o.

This can be used together with raiseUnder in order to create -AssocR variants out of regular Writer interpreters.

valuerunWriterSTMAction

A variant of runWriterTVar where an STM action is used instead of a TVar to commit tells.

valueinterpretViaLazyWriter

:: Monoid o
=> forall (m :: Type -> Type) x. Monad m => Weaving e (WriterT o m) x -> WriterT o m x
-> Sem (e ': r) a
-> Sem r (o, a)