Control.Monad.Trans.List

A list monad transformer / a monadic list.

Monadic list example: A program which reads numbers from the user and accumulates them.

 import Control.Monad.Trans.List.Funcs (repeatM)
 import Data.List.Class (execute, scanl, takeWhile, mapL)
 import Prelude hiding (scanl, takeWhile)
 
 main =
     execute . mapL print .
     scanl (+) 0 .
     fmap (fst . head) .
     takeWhile (not . null) .
     fmap reads $ repeatM getLine

Documentation

newtype ListT m a

Constructors

ListT

Fields

runListT :: m (ListItem (ListT m) a)

Instances

MonadTrans ListT

Monad m => Monad (ListT m)

Monad m => Functor (ListT m)

(Monad (ListT m), Monad m) => MonadPlus (ListT m)

(Functor (ListT m), Monad m) => Applicative (ListT m)

(Monad (ListT m), MonadIO m) => MonadIO (ListT m)

(MonadPlus (ListT m), Monad (ItemM (ListT m)), Monad m) => List (ListT m)

Eq (m (ListItem (ListT m) a)) => Eq (ListT m a)

(Eq (ListT m a), Ord (m (ListItem (ListT m) a))) => Ord (ListT m a)

Read (m (ListItem (ListT m) a)) => Read (ListT m a)

Show (m (ListItem (ListT m) a)) => Show (ListT m a)

Monad m => Monoid (ListT m a)