Safe Haskell	Safe-Inferred
Language	Haskell2010

Control.Monad.Trans.List

Description

Free list monad transformer

Synopsis

newtype ListT m a = ListT {
- getListT :: FreeT [] m a
}
flatten :: Monad m => ListT m a -> ListT m a
runListT :: Monad m => ListT m a -> m [a]
listT :: Monad m => m [a] -> ListT m a
singleton :: Functor m => m a -> ListT m a

Documentation

newtype ListT m a Source #

The free list monad transformer.

It is implemented as a rose tree (see https://en.wikipedia.org/wiki/Rose_tree) of computations in m.

Constructors

ListT
Fields getListT :: FreeT [] m a

Instances

Instances details

MonadTrans ListT Source #
Instance details Defined in Control.Monad.Trans.List Methods lift :: Monad m => m a -> ListT m a #
(MonadReader r m, MonadWriter w m, MonadState s m) => MonadRWS r w s (ListT m) Source #
Instance details Defined in Control.Monad.Trans.List
MonadError e m => MonadError e (ListT m) Source #
Instance details Defined in Control.Monad.Trans.List Methods throwError :: e -> ListT m a # catchError :: ListT m a -> (e -> ListT m a) -> ListT m a #
MonadReader r m => MonadReader r (ListT m) Source #
Instance details Defined in Control.Monad.Trans.List Methods ask :: ListT m r # local :: (r -> r) -> ListT m a -> ListT m a # reader :: (r -> a) -> ListT m a #
MonadState s m => MonadState s (ListT m) Source #
Instance details Defined in Control.Monad.Trans.List Methods get :: ListT m s # put :: s -> ListT m () # state :: (s -> (a, s)) -> ListT m a #
MonadWriter w m => MonadWriter w (ListT m) Source #
Instance details Defined in Control.Monad.Trans.List Methods writer :: (a, w) -> ListT m a # tell :: w -> ListT m () # listen :: ListT m a -> ListT m (a, w) # pass :: ListT m (a, w -> w) -> ListT m a #
MonadFail m => MonadFail (ListT m) Source #
Instance details Defined in Control.Monad.Trans.List Methods fail :: String -> ListT m a #
MonadIO m => MonadIO (ListT m) Source #
Instance details Defined in Control.Monad.Trans.List Methods liftIO :: IO a -> 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 #
MonadPlus 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 => 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 #
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 #
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 #
MonadPlus 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 #
MonadCatch m => MonadCatch (ListT m) Source #
Instance details Defined in Control.Monad.Trans.List Methods catch :: (HasCallStack, Exception e) => ListT m a -> (e -> ListT m a) -> ListT m a #
MonadThrow m => MonadThrow (ListT m) Source #
Instance details Defined in Control.Monad.Trans.List Methods throwM :: (HasCallStack, Exception e) => e -> 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 #
(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 #

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

Flatten all layers of computations to a single one.

runListT :: Monad m => ListT m a -> m [a] Source #

Like flatten, but remove the ListT wrapper.

listT :: Monad m => m [a] -> ListT m a Source #

Construct a ListT from an effectful list (a single layer).

singleton :: Functor m => m a -> ListT m a Source #

Construct a ListT from a single effectful value.