Copyright	(c) Andy Gill 2001, (c) Oregon Graduate Institute of Science and Technology, 2001
License	BSD-style (see the file LICENSE)
Maintainer	ross@soi.city.ac.uk
Stability	experimental
Portability	portable
Safe Haskell	Safe
Language	Haskell98

Control.Monad.Trans.List

Contents

Description

The ListT monad transformer, adding backtracking to a given monad, which must be commutative.

Synopsis

The ListT monad transformer

newtype ListT m a Source

Parameterizable list monad, with an inner monad.

Note: this does not yield a monad unless the argument monad is commutative.

Constructors

ListT
Fields runListT :: m [a]

Instances

MonadTrans ListT
Monad m => Monad (ListT m)
Functor m => Functor (ListT m)
Applicative m => Applicative (ListT m)
Foldable f => Foldable (ListT f)
Traversable f => Traversable (ListT f)
Applicative m => Alternative (ListT m)
Monad m => MonadPlus (ListT m)
MonadIO m => MonadIO (ListT m)
Show1 m => Show1 (ListT m)
Read1 m => Read1 (ListT m)
Ord1 m => Ord1 (ListT m)
Eq1 m => Eq1 (ListT m)
(Eq1 m, Eq a) => Eq (ListT m a)
(Ord1 m, Ord a) => Ord (ListT m a)
(Read1 m, Read a) => Read (ListT m a)
(Show1 m, Show a) => Show (ListT m a)

mapListT :: (m [a] -> n [b]) -> ListT m a -> ListT n b Source

Map between ListT computations.

runListT (mapListT f m) = f (runListT m)

Lifting other operations

Lift a callCC operation to the new monad.

Lift a catchE operation to the new monad.