-- Hoogle documentation, generated by Haddock
-- See Hoogle, http://www.haskell.org/hoogle/
-- | Sensible conversions between some of the monad transformers
--
-- Sensible conversions between MaybeT and EitherT monad transformers.
@package transformers-convert
@version 0.2.0.0
module Control.Monad.Trans.Convert
-- | Transform a maybe value encapsulated in a Monad m into the
-- equivalent MaybeT m monad transformer.
--
-- NOTE: this is not equivalent to either lift or
-- hoistMaybe alone. Check the types carefully.
mMaybeToMaybeT :: Monad m => m (Maybe a) -> MaybeT m a
-- | Shorter alias for mMaybeToMaybeT
mMToMT :: Monad m => m (Maybe a) -> MaybeT m a
-- | Transform a IO (Maybe a) value into a MaybeT IO a value
ioMaybeToMaybeT :: IO (Maybe a) -> MaybeT IO a
-- | Shorter alias for ioMaybeToMaybeT
ioMToMT :: IO (Maybe a) -> MaybeT IO a
-- | Transform a either value encapsulated in a Monad m into the
-- equivalent MaybeT m monad transformer.
--
-- Note: The left value is silently discarded.
mEitherToMaybeT :: Functor m => m (Either a b) -> MaybeT m b
-- | Shorter alias for mEitherToMaybeT.
mEToMT :: (Functor m, Monad m) => m (Either a b) -> MaybeT m b
-- | Transform a either value encapsulated in a IO monad into the
-- equivalent MaybeT IO monad transformer.
--
-- Note: The left value is silently discarded.
ioEitherToMaybeT :: IO (Either a b) -> MaybeT IO b
-- | Shorter alias for mEitherToMaybeT.
ioEToMT :: IO (Either a b) -> MaybeT IO b
-- | Case analysis of a pair of monoid values returned by a monad into a
-- MaybeT value. The value conversion is done by
-- pairToMaybe.
mPairToMaybeT :: (Eq a, Monoid a, Functor m, Monad m) => m (a, a) -> MaybeT m a
-- | Case analysis of a pair of monoid values returned by a monad into a
-- MaybeT value. The value conversion is done by
-- pairToMaybe'.
mPairToMaybeT' :: (Eq a, Monoid a, Functor m, Monad m) => m (a, a) -> MaybeT m a
-- | Case analysis of a pair of monoid values returned by a monad into a
-- MaybeT value. The value conversion is done by
-- pairFstToMaybe.
mPairFstToMaybeT :: (Eq a, Monoid a, Functor m, Monad m) => m (a, b) -> MaybeT m a
-- | Case analysis of a pair of monoid values returned by a monad into a
-- MaybeT value. The value conversion is done by
-- pairSndToMaybe.
mPairSndToMaybeT :: (Eq b, Monoid b, Functor m, Monad m) => m (a, b) -> MaybeT m b
-- | Transform a monoid value encapsulated in a Monad m into the
-- equivalent MaybeT m monad transformer (mempty ->
-- Nothing).
mMonoidToMaybeT :: (Eq o, Monoid o, Functor m, Monad m) => m o -> MaybeT m o
-- | Shorter alias for mMonoidToMaybeT
mOToMT :: (Eq o, Monoid o, Functor m, Monad m) => m o -> MaybeT m o
-- | Transform a boolean value encapsulated in a Monad m into the
-- equivalent MaybeT m monad transformer (True ->
-- Provided Default Value).
mBoolToMaybeT :: (Functor m, Monad m) => a -> m Bool -> MaybeT m a
-- | Shorter alias for mBoolToMaybeT.
mBToMT :: (Functor m, Monad m) => a -> m Bool -> MaybeT m a
tryIOMonoidToMaybeT :: (Eq a, Monoid a) => IO a -> MaybeT IO a
tryIOMT :: (Eq a, Monoid a) => IO a -> MaybeT IO a
-- | Transform a maybe value encapsulated in a Monad m into the
-- equivalent EitherT b m monad transformer.
--
-- NOTE: this is not equivalent to either lift or
-- hoistEither alone. Check the types carefully.
mMaybeToEitherT :: Monad m => b -> m (Maybe a) -> EitherT b m a
-- | Shorter alias for mMaybeToEitherT
mMToET :: Monad m => b -> m (Maybe a) -> EitherT b m a
-- | Transform a IO (Maybe a) value into a EitherT b IO a value
ioMaybeToEitherT :: b -> IO (Maybe a) -> EitherT b IO a
-- | Shorter alias for ioMaybeToEitherT
ioMToET :: b -> IO (Maybe a) -> EitherT b IO a
-- | Transform a either value encapsulated in a Monad m into the
-- equivalent EitherT e m monad transformer.
mEitherToEitherT :: Monad m => m (Either b a) -> EitherT b m a
-- | Shorter alias for mEitherToEitherT.
mEToET :: Monad m => m (Either b a) -> EitherT b m a
-- | Transform a either value encapsulated in a IO monad into the
-- equivalent EitherT b IO monad transformer.
ioEitherToEitherT :: IO (Either b a) -> EitherT b IO a
-- | Shorter alias for mEitherToEitherT.
ioEToET :: IO (Either b a) -> EitherT b IO a
-- | Case analysis of a pair of monoid values returned by a monad into a
-- EitherT value. The value conversion is done by
-- pairToEither.
mPairToEitherT :: (Eq a, Monoid a, Functor m, Monad m) => m (b, a) -> EitherT b m a
-- | Case analysis of a pair of monoid values returned by a monad into a
-- EitherT value. The value conversion is done by
-- pairToEither'.
mPairToEitherT' :: (Eq b, Monoid b, Functor m, Monad m) => m (b, a) -> EitherT a m b
-- | Case analysis of a pair of monoid values returned by a monad into a
-- EitherT value. The value conversion is done by
-- pairBothToEither.
mPairBothToEitherT :: (Eq a, Monoid a, Functor m, Monad m) => b -> m (a, a) -> EitherT b m a
-- | Transform a monoid value encapsulated in a Monad m into the
-- equivalent EitherT e m monad transformer (mempty ->
-- Nothing).
mMonoidToEitherT :: (Eq a, Monoid a, Functor m, Monad m) => b -> m a -> EitherT b m a
-- | Shorter alias for mMonoidToEitherT
mOToET :: (Eq a, Monoid a, Functor m, Monad m) => b -> m a -> EitherT b m a
-- | Transform a boolean value encapsulated in a Monad m into the
-- equivalent Either m monad transformer. Uses
-- boolToEither.
mBoolToEitherT :: (Functor m, Monad m) => b -> a -> m Bool -> EitherT b m a
-- | Shorter alias for mBoolToEitherT.
mBToET :: (Functor m, Monad m) => b -> a -> m Bool -> EitherT b m a
-- | Change the left type using the provided conversion function. This is a
-- specialization of bimapEitherT.
--
--
-- fmapLeftT f = bimapEitherT f id
--
--
-- or using the errors Data.EitherR
--
--
-- fmapLeftT = fmapLT
--
fmapLeftT :: Functor m => (a -> c) -> EitherT a m b -> EitherT c m b
-- | Change the right type using the provided conversion function. This is
-- a specialization of bimapEitherT.
fmapRightT :: Functor m => (b -> c) -> EitherT a m b -> EitherT a m c
tryIOMonoidToEitherT :: (Eq a, Monoid a) => IO a -> EitherT IOException IO a
-- | This function executes a IO action that could raise an
-- IOException. If a IOException is
-- raised, the function returns a left value in the EitherT
-- IOException IO monad transformer.
tryIOET :: IO a -> EitherT IOException IO a
-- | This function executes a IO action that returns a monoid value, or
-- raises an IOException. If a
-- IOException is raised, or the returned value is an
-- empty monoid, the function returns a left value in the EitherT
-- IOException IO monad transformer. In the later case (empty
-- monoid), the exception will be of userErrorType type,
-- with the provided string text.
tryIOET' :: (Eq a, Monoid a) => String -> IO a -> EitherT IOException IO a