Control.Monad.Trans.Journal

JournalT monad transformer

data JournalT w m a

Instances

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

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

data StT (JournalT w) = StJournal {

• unStJournal :: (a, w)

}

data StM (JournalT w m) = StMJournal {

• unStMJournal :: 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.

module Control.Monad.Journal.Class