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

Control.Monad.Trans.List

Contents

The ListT monad transformer
Lifting other operations

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 Source #
Methods lift :: Monad m => m a -> ListT m a Source #
Monad m => Monad (ListT m) Source #
Methods (>>=) :: ListT m a -> (a -> ListT m b) -> ListT m b # (>>) :: ListT m a -> ListT m b -> ListT m b # return :: a -> ListT m a # fail :: String -> ListT m a #
Functor m => Functor (ListT m) Source #
Methods fmap :: (a -> b) -> ListT m a -> ListT m b # (<$) :: a -> ListT m b -> ListT m a #
Monad m => MonadFail (ListT m) Source #
Methods fail :: String -> ListT m a #
Applicative m => Applicative (ListT m) Source #
Methods pure :: a -> ListT m a # (<>) :: ListT m (a -> b) -> ListT m a -> ListT m b # liftA2 :: (a -> b -> c) -> ListT m a -> ListT m b -> ListT m c # (>) :: ListT m a -> ListT m b -> ListT m b # (<*) :: ListT m a -> ListT m b -> ListT m a #
Foldable f => Foldable (ListT f) Source #
Methods fold :: Monoid m => ListT f m -> m # foldMap :: Monoid m => (a -> m) -> ListT f a -> m # foldr :: (a -> b -> b) -> b -> ListT f a -> b # foldr' :: (a -> b -> b) -> b -> ListT f a -> b # foldl :: (b -> a -> b) -> b -> ListT f a -> b # foldl' :: (b -> a -> b) -> b -> ListT f a -> b # foldr1 :: (a -> a -> a) -> ListT f a -> a # foldl1 :: (a -> a -> a) -> ListT f a -> a # toList :: ListT f a -> [a] # null :: ListT f a -> Bool # length :: ListT f a -> Int # elem :: Eq a => a -> ListT f a -> Bool # maximum :: Ord a => ListT f a -> a # minimum :: Ord a => ListT f a -> a # sum :: Num a => ListT f a -> a # product :: Num a => ListT f a -> a #
Traversable f => Traversable (ListT f) Source #
Methods traverse :: Applicative f => (a -> f b) -> ListT f a -> f (ListT f b) # sequenceA :: Applicative f => ListT f (f a) -> f (ListT f a) # mapM :: Monad m => (a -> m b) -> ListT f a -> m (ListT f b) # sequence :: Monad m => ListT f (m a) -> m (ListT f a) #
Eq1 m => Eq1 (ListT m) Source #
Methods liftEq :: (a -> b -> Bool) -> ListT m a -> ListT m b -> Bool #
Ord1 m => Ord1 (ListT m) Source #
Methods liftCompare :: (a -> b -> Ordering) -> ListT m a -> ListT m b -> Ordering #
Read1 m => Read1 (ListT m) Source #
Methods liftReadsPrec :: (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (ListT m a) # liftReadList :: (Int -> ReadS a) -> ReadS [a] -> ReadS [ListT m a] # liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec (ListT m a) # liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [ListT m a] #
Show1 m => Show1 (ListT m) Source #
Methods liftShowsPrec :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> ListT m a -> ShowS # liftShowList :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> [ListT m a] -> ShowS #
MonadZip m => MonadZip (ListT m) Source #
Methods mzip :: ListT m a -> ListT m b -> ListT m (a, b) # mzipWith :: (a -> b -> c) -> ListT m a -> ListT m b -> ListT m c # munzip :: ListT m (a, b) -> (ListT m a, ListT m b) #
MonadIO m => MonadIO (ListT m) Source #
Methods liftIO :: IO a -> ListT m a #
Applicative m => Alternative (ListT m) Source #
Methods empty :: ListT m a # (<\|>) :: ListT m a -> ListT m a -> ListT m a # some :: ListT m a -> ListT m [a] # many :: ListT m a -> ListT m [a] #
Monad m => MonadPlus (ListT m) Source #
Methods mzero :: ListT m a # mplus :: ListT m a -> ListT m a -> ListT m a #
(Eq1 m, Eq a) => Eq (ListT m a) Source #
Methods (==) :: ListT m a -> ListT m a -> Bool # (/=) :: ListT m a -> ListT m a -> Bool #
(Ord1 m, Ord a) => Ord (ListT m a) Source #
Methods compare :: ListT m a -> ListT m a -> Ordering # (<) :: ListT m a -> ListT m a -> Bool # (<=) :: ListT m a -> ListT m a -> Bool # (>) :: ListT m a -> ListT m a -> Bool # (>=) :: ListT m a -> ListT m a -> Bool # max :: ListT m a -> ListT m a -> ListT m a # min :: ListT m a -> ListT m a -> ListT m a #
(Read1 m, Read a) => Read (ListT m a) Source #
Methods readsPrec :: Int -> ReadS (ListT m a) # readList :: ReadS [ListT m a] # readPrec :: ReadPrec (ListT m a) # readListPrec :: ReadPrec [ListT m a] #
(Show1 m, Show a) => Show (ListT m a) Source #
Methods showsPrec :: Int -> ListT m a -> ShowS # show :: ListT m a -> String # showList :: [ListT m a] -> ShowS #

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

liftCallCC :: CallCC m [a] [b] -> CallCC (ListT m) a b Source #

Lift a callCC operation to the new monad.

liftCatch :: Catch e m [a] -> Catch e (ListT m) a Source #

Lift a catchE operation to the new monad.