Control.Monad.Trans.Journal

Monad transformer version of MonadJournal. JournalT provides journaling over a monad.

This modules defines a few useful instances. Check the list below for further information.

JournalT monad transformer

data JournalT w m a

Transformer version of MonadJournal.

Instances

MonadBase b m => MonadBase b (JournalT w m)

(Monoid w, MonadBaseControl b m) => MonadBaseControl b (JournalT w m)

MonadError e m => MonadError e (JournalT w m)

MonadReader r m => MonadReader r (JournalT w m)

MonadState s m => MonadState s (JournalT w m)

MonadWriter w' m => MonadWriter w' (JournalT w m)

(Monoid w, Monad m) => MonadJournal w (JournalT w m)

MonadTrans (JournalT w)

Monoid w => MonadTransControl (JournalT w)

(Functor m, MonadPlus m) => Alternative (JournalT w m)

Monad m => Monad (JournalT w m)

Functor m => Functor (JournalT w m)

MonadPlus m => MonadPlus (JournalT w m)

(Monad m, Functor m) => Applicative (JournalT w m)

MonadIO m => MonadIO (JournalT w m)

type StT (JournalT w) a = (a, w)

type StM (JournalT w m) a = ComposeSt (JournalT w) m a

runJournalT :: (Monoid w, Monad m) => JournalT w m a -> m (a, w)

Retrieve the value and the log history.

evalJournalT :: (Monoid w, Monad m) => JournalT w m a -> m a

Only retrieve the value.

execJournalT :: (Monoid w, Monad m) => JournalT w m a -> m w

Only retrieve the log history.

Re-exported

module Control.Monad.Journal.Class