Copyright	C. Maeder and Uni Bremen 2002-2005
License	GPLv2 or higher, see LICENSE.txt
Maintainer	jonathan.von_schroeder@dfki.de
Stability	experimental
Portability	portable
Safe Haskell	Safe

Common.Lib.Maybe

Description

This module is a replacement of module Control.Monad.Maybe and only contains the Monad instance for the newtype MaybeT m.

Synopsis

Documentation

newtype MaybeT m a Source #

A monad transformer which adds Maybe semantics to an existing monad.

Constructors

MaybeT
Fields runMaybeT :: m (Maybe a)

Instances details

Monad m => Monad (MaybeT m) Source #
Instance details Defined in Common.Lib.Maybe Methods (>>=) :: MaybeT m a -> (a -> MaybeT m b) -> MaybeT m b (>>) :: MaybeT m a -> MaybeT m b -> MaybeT m b return :: a -> MaybeT m a
Monad m => Functor (MaybeT m) Source #
Instance details Defined in Common.Lib.Maybe Methods fmap :: (a -> b) -> MaybeT m a -> MaybeT m b (<$) :: a -> MaybeT m b -> MaybeT m a
Monad m => MonadFail (MaybeT m) Source #
Instance details Defined in Common.Lib.Maybe Methods fail :: String -> MaybeT m a
Monad m => Applicative (MaybeT m) Source #
Instance details Defined in Common.Lib.Maybe Methods pure :: a -> MaybeT m a (<>) :: MaybeT m (a -> b) -> MaybeT m a -> MaybeT m b liftA2 :: (a -> b -> c) -> MaybeT m a -> MaybeT m b -> MaybeT m c (>) :: MaybeT m a -> MaybeT m b -> MaybeT m b (<*) :: MaybeT m a -> MaybeT m b -> MaybeT m a

liftToMaybeT :: Monad m => m a -> MaybeT m a Source #