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

PMonad MaybeP

PFunctor MaybeP

Proxy p => MonadPlusP (MaybeP p)

Proxy p => ProxyInternal (MaybeP p)

Proxy p => Proxy (MaybeP p)

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

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

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

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

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

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

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

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

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 m, Proxy p) => MaybeP p a' a b' b m r

A synonym for mzero

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

A synonym for return