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 => Alternative (ListT m)

Monad m => Monad (ListT m)

Monad m => Functor (ListT m)

Monad m => MonadPlus (ListT m)

Monad m => Applicative (ListT m)

MonadIO m => MonadIO (ListT m)

Monad m => List (ListT m)

Eq (m (ListItem (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)

type ItemM (ListT m) = m