Control.Proxy.Trans.Maybe

This module provides the proxy transformer equivalent of MaybeT.

MaybeP

newtype MaybeP p a' a b' b m r

The Maybe proxy transformer

Constructors

MaybeP

Fields

• runMaybeP :: p a' a b' b m (Maybe r)

Instances

ProxyTrans MaybeP

Methods

liftP :: (Monad (p b c d e m), Channel p) => p b c d e m r -> MaybeP p b c d e m r

mapP :: (Monad (p b c d e m), Channel p) => (a -> p b c d e m r) -> a -> MaybeP p b c d e m r

Channel p => Channel (MaybeP p)

Methods

idT :: Monad m => a' -> MaybeP p a' a a' a m r

(>->) :: Monad m => (b' -> MaybeP p a' a b' b m r) -> (c' -> MaybeP p b' b c' c m r) -> c' -> MaybeP p a' a c' c m r

(<-<) :: Monad m => (c' -> MaybeP p b' b c' c m r) -> (b' -> MaybeP p a' a b' b m r) -> c' -> MaybeP p a' a c' c m r

MonadTrans (p a' a b' b) => MonadTrans (MaybeP p a' a b' b)

Methods

lift :: Monad m => m a -> MaybeP p a' a b' b m a

MFunctor (p a' a b' b) => MFunctor (MaybeP p a' a b' b)

Methods

mapT :: (Monad m, Monad n) => (forall c. m c -> n c) -> MaybeP p a' a b' b m b -> MaybeP p a' a b' b n b

Monad (p a' a b' b m) => Monad (MaybeP p a' a b' b m)

Methods

(>>=) :: MaybeP p a' a b' b m a -> (a -> MaybeP p a' a b' b m b) -> MaybeP p a' a b' b m b

(>>) :: MaybeP p a' a b' b m a -> MaybeP p a' a b' b m b -> MaybeP p a' a b' b m b

return :: a -> MaybeP p a' a b' b m a

fail :: String -> MaybeP p a' a b' b m a

Monad (p a' a b' b m) => Functor (MaybeP p a' a b' b m)

Methods

fmap :: (a -> b) -> MaybeP p a' a b' b m a -> MaybeP p a' a b' b m b

(<$) :: a -> MaybeP p a' a b' b m b -> MaybeP p a' a b' b m a

Monad (p a' a b' b m) => Applicative (MaybeP p a' a b' b m)

Methods

pure :: a -> MaybeP p a' a b' b m a

(<*>) :: MaybeP p a' a b' b m (a -> b) -> MaybeP p a' a b' b m a -> MaybeP p a' a b' b m b

(*>) :: MaybeP p a' a b' b m a -> MaybeP p a' a b' b m b -> MaybeP p a' a b' b m b

(<*) :: MaybeP p a' a b' b m a -> MaybeP p a' a b' b m b -> MaybeP p a' a b' b m a

MonadIO (p a' a b' b m) => MonadIO (MaybeP p a' a b' b m)

Methods

liftIO :: IO a -> MaybeP p a' a b' b m a

Monad (p a' a b' b m) => Alternative (MaybeP p a' a b' b m)

Methods

empty :: MaybeP p a' a b' b m a

(<|>) :: MaybeP p a' a b' b m a -> MaybeP p a' a b' b m a -> MaybeP p a' a b' b m a

some :: MaybeP p a' a b' b m a -> MaybeP p a' a b' b m [a]

many :: MaybeP p a' a b' b m a -> MaybeP p a' a b' b m [a]

Monad (p a' a b' b m) => MonadPlus (MaybeP p a' a b' b m)

Methods

mzero :: MaybeP p a' a b' b m a

mplus :: MaybeP p a' a b' b m a -> MaybeP p a' a b' b m a -> MaybeP p a' a b' b m a

runMaybeK :: (q -> MaybeP p a' a b' b m r) -> q -> p a' a b' b m (Maybe r)

Run a MaybeP 'K'leisli arrow, returning the result or Nothing

Maybe operations

nothing :: Monad (p a' a b' b m) => MaybeP p a' a b' b m r

A synonym for mzero

just :: Monad (p a' a b' b m) => r -> MaybeP p a' a b' b m r

A synonym for return