Control.Proxy.Trans.Either

This module provides the proxy transformer equivalent of EitherT.

EitherP

newtype EitherP e p a' a b' b m r

The Either proxy transformer

Constructors

EitherP

Fields

• runEitherP :: p a' a b' b m (Either e r)

Instances

ProxyTrans (EitherP e)

Methods

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

Channel p => Channel (EitherP e p)

Methods

idT :: Monad m => a' -> EitherP e p a' a a' a m r

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

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

MonadTrans (p a' a b' b) => MonadTrans (EitherP e p a' a b' b)

Methods

lift :: Monad m => m a -> EitherP e p a' a b' b m a

MFunctor (p a' a b' b) => MFunctor (EitherP e p a' a b' b)

Methods

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

Monad (p a' a b' b m) => Monad (EitherP e p a' a b' b m)

Methods

(>>=) :: EitherP e p a' a b' b m a -> (a -> EitherP e p a' a b' b m b) -> EitherP e p a' a b' b m b

(>>) :: EitherP e p a' a b' b m a -> EitherP e p a' a b' b m b -> EitherP e p a' a b' b m b

return :: a -> EitherP e p a' a b' b m a

fail :: String -> EitherP e p a' a b' b m a

Monad (p a' a b' b m) => Functor (EitherP e p a' a b' b m)

Methods

fmap :: (a -> b) -> EitherP e p a' a b' b m a -> EitherP e p a' a b' b m b

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

Monad (p a' a b' b m) => Applicative (EitherP e p a' a b' b m)

Methods

pure :: a -> EitherP e p a' a b' b m a

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

(*>) :: EitherP e p a' a b' b m a -> EitherP e p a' a b' b m b -> EitherP e p a' a b' b m b

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

MonadIO (p a' a b' b m) => MonadIO (EitherP e p a' a b' b m)

Methods

liftIO :: IO a -> EitherP e p a' a b' b m a

MonadPlus (p a' a b' b m) => Alternative (EitherP e p a' a b' b m)

Methods

empty :: EitherP e p a' a b' b m a

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

some :: EitherP e p a' a b' b m a -> EitherP e p a' a b' b m [a]

many :: EitherP e p a' a b' b m a -> EitherP e p a' a b' b m [a]

MonadPlus (p a' a b' b m) => MonadPlus (EitherP e p a' a b' b m)

Methods

mzero :: EitherP e p a' a b' b m a

mplus :: EitherP e p a' a b' b m a -> EitherP e p a' a b' b m a -> EitherP e p a' a b' b m a

runEitherK :: (q -> EitherP e p a' a b' b m r) -> q -> p a' a b' b m (Either e r)

Run an EitherP 'K'leisi arrow, returning either a Left or Right

Either operations

left :: Monad (p a' a b' b m) => e -> EitherP e p a' a b' b m r

Abort the computation and return a Left result

right :: Monad (p a' a b' b m) => r -> EitherP e p a' a b' b m r

Synonym for return

Symmetric monad

EitherP forms a second symmetric monad over the left type variable.

throw is symmetric to return

catch is symmetric to (>>=)

These two functions obey the monad laws:

catch m throw = m

catch (throw e) f = f e

catch (catch m f) g = catch m (\e -> catch (f e) g)

throw :: Monad (p a' a b' b m) => e -> EitherP e p a' a b' b m r

Synonym for left

catch

Arguments

:: Monad (p a' a b' b m)

=> EitherP e p a' a b' b m r

Original computation

-> (e -> EitherP f p a' a b' b m r)

Handler

-> EitherP f p a' a b' b m r

Handled computation

Resume from an aborted operation

handle

Arguments

:: Monad (p a' a b' b m)

=> (e -> EitherP f p a' a b' b m r)

Handler

-> EitherP e p a' a b' b m r

Original computation

-> EitherP f p a' a b' b m r

Handled computation

catch with the arguments flipped