Control.Monad.Writer.Stricter

Documentation

data WriterT s m a

A monad transformer similar to WriterT, except that it does not leak space.

Instances

(Monoid s, Monad m) => MonadWriter s (WriterT s m)

Methods

writer :: (a, s) -> WriterT s m a

tell :: s -> WriterT s m ()

listen :: WriterT s m a -> WriterT s m (a, s)

pass :: WriterT s m (a, s -> s) -> WriterT s m a

MonadTrans (WriterT s)

Methods

lift :: Monad m => m a -> WriterT s m a

Monad m => Monad (WriterT s m)

Methods

(>>=) :: WriterT s m a -> (a -> WriterT s m b) -> WriterT s m b

(>>) :: WriterT s m a -> WriterT s m b -> WriterT s m b

return :: a -> WriterT s m a

fail :: String -> WriterT s m a

Functor m => Functor (WriterT s m)

Methods

fmap :: (a -> b) -> WriterT s m a -> WriterT s m b

(<$) :: a -> WriterT s m b -> WriterT s m a

Monad m => Applicative (WriterT s m)

Methods

pure :: a -> WriterT s m a

(<*>) :: WriterT s m (a -> b) -> WriterT s m a -> WriterT s m b

(*>) :: WriterT s m a -> WriterT s m b -> WriterT s m b

(<*) :: WriterT s m a -> WriterT s m b -> WriterT s m a

(Alternative m, Monad m, Monoid s) => Alternative (WriterT s m)

Methods

empty :: WriterT s m a

(<|>) :: WriterT s m a -> WriterT s m a -> WriterT s m a

some :: WriterT s m a -> WriterT s m [a]

many :: WriterT s m a -> WriterT s m [a]

runWriterT :: Monoid s => WriterT s m a -> m (a, s)

pattern WriterT :: forall m s a. (Functor m, Monoid s) => m (a, s) -> WriterT s m a

type Weighted s = WriterT s Identity

runWeighted :: Monoid s => Weighted s a -> (a, s)

pattern Weighted :: forall s a. Monoid s => (a, s) -> Weighted s a

execWriterT :: (Monad m, Monoid s) => WriterT s m a -> m s

evalWriterT :: (Monad m, Monoid s) => WriterT s m a -> m a

execWeighted :: Monoid s => Weighted s a -> s

evalWeighted :: Monoid s => Weighted s a -> a