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

Deprecated: This transformer is invalid on most monads

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

Synopsis

newtype ListT m a = ListT {
- runListT :: m [a]
}
mapListT :: (m [a] -> n [b]) -> ListT m a -> ListT n b
liftCallCC :: CallCC m [a] [b] -> CallCC (ListT m) a b
liftCatch :: Catch e m [a] -> Catch e (ListT m) a

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

ListT Source #

Instance details

Defined in Control.Monad.Trans.List

Methods

lift :: Monad m => m a -> ListT m a Source #

Monad m => Monad (ListT m) Source #

Instance details

Defined in Control.Monad.Trans.List

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 #

Instance details

Defined in Control.Monad.Trans.List

Methods

fmap :: (a -> b) -> ListT m a -> ListT m b #

(<$) :: a -> ListT m b -> ListT m a #

MonadFix m => MonadFix (ListT m) Source #

Instance details

Defined in Control.Monad.Trans.List

Methods

mfix :: (a -> ListT m a) -> ListT m a #

Monad m => MonadFail (ListT m) Source #

Instance details

Defined in Control.Monad.Trans.List

Methods

fail :: String -> ListT m a #

Applicative m => Applicative (ListT m) Source #

Instance details

Defined in Control.Monad.Trans.List

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 #

Instance details

Defined in Control.Monad.Trans.List

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 #

Instance details

Defined in Control.Monad.Trans.List

Methods

traverse :: Applicative f0 => (a -> f0 b) -> ListT f a -> f0 (ListT f b) #

sequenceA :: Applicative f0 => ListT f (f0 a) -> f0 (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) #

Contravariant m => Contravariant (ListT m) Source #

Instance details

Defined in Control.Monad.Trans.List

Methods

contramap :: (a -> b) -> ListT m b -> ListT m a #

(>$) :: b -> ListT m b -> ListT m a #

Eq1 m => Eq1 (ListT m) Source #

Instance details

Defined in Control.Monad.Trans.List

Methods

liftEq :: (a -> b -> Bool) -> ListT m a -> ListT m b -> Bool #

Ord1 m => Ord1 (ListT m) Source #

Instance details

Defined in Control.Monad.Trans.List

Methods

liftCompare :: (a -> b -> Ordering) -> ListT m a -> ListT m b -> Ordering #

Read1 m => Read1 (ListT m) Source #

Instance details

Defined in Control.Monad.Trans.List

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 #

Instance details

Defined in Control.Monad.Trans.List

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 #

Instance details

Defined in Control.Monad.Trans.List

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 #

Instance details

Defined in Control.Monad.Trans.List

Methods

liftIO :: IO a -> ListT m a #

Applicative m => Alternative (ListT m) Source #

Instance details

Defined in Control.Monad.Trans.List

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 #

Instance details

Defined in Control.Monad.Trans.List

Methods

mzero :: ListT m a #

mplus :: ListT m a -> ListT m a -> ListT m a #

(Eq1 m, Eq a) => Eq (ListT m a) Source #

Instance details

Defined in Control.Monad.Trans.List

Methods

(==) :: ListT m a -> ListT m a -> Bool #

(/=) :: ListT m a -> ListT m a -> Bool #

(Ord1 m, Ord a) => Ord (ListT m a) Source #

Instance details

Defined in Control.Monad.Trans.List

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 #

Instance details

Defined in Control.Monad.Trans.List

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 #

Instance details

Defined in Control.Monad.Trans.List

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.