Control.Monad.Trans.State.Plus

MonadPlus with left catch (MonadOr) for StateT.

The StatePlusT monad transformer

data StatePlusT s m a

StatePlusT behaves similar to StateT monad transformer

Instances

Monad m => MonadState s (StatePlusT s m)

Methods

get :: StatePlusT s m s

put :: s -> StatePlusT s m ()

state :: (s -> (a, s)) -> StatePlusT s m a

MonadTrans (StatePlusT s)

Methods

lift :: Monad m => m a -> StatePlusT s m a

Monad m => Monad (StatePlusT s m)

Methods

(>>=) :: StatePlusT s m a -> (a -> StatePlusT s m b) -> StatePlusT s m b

(>>) :: StatePlusT s m a -> StatePlusT s m b -> StatePlusT s m b

return :: a -> StatePlusT s m a

fail :: String -> StatePlusT s m a

Functor m => Functor (StatePlusT s m)

Methods

fmap :: (a -> b) -> StatePlusT s m a -> StatePlusT s m b

(<$) :: a -> StatePlusT s m b -> StatePlusT s m a

(Monad m, Functor m) => Applicative (StatePlusT s m)

Methods

pure :: a -> StatePlusT s m a

(<*>) :: StatePlusT s m (a -> b) -> StatePlusT s m a -> StatePlusT s m b

(*>) :: StatePlusT s m a -> StatePlusT s m b -> StatePlusT s m b

(<*) :: StatePlusT s m a -> StatePlusT s m b -> StatePlusT s m a

MonadIO m => MonadIO (StatePlusT s m)

Methods

liftIO :: IO a -> StatePlusT s m a

(Monad m, Functor m) => Alternative (StatePlusT s m)

Methods

empty :: StatePlusT s m a

(<|>) :: StatePlusT s m a -> StatePlusT s m a -> StatePlusT s m a

some :: StatePlusT s m a -> StatePlusT s m [a]

many :: StatePlusT s m a -> StatePlusT s m [a]

Monad m => MonadPlus (StatePlusT s m)

Methods

mzero :: StatePlusT s m a

mplus :: StatePlusT s m a -> StatePlusT s m a -> StatePlusT s m a

runStatePlusT :: Monad m => StatePlusT s m a -> s -> m (Maybe a, s)

Evaluate StatePlusT monad. In difference from runStateT it returns Nothing if mzero has been encountered. Just a otherwise.

execStatePlusT :: Monad m => StatePlusT s m a -> s -> m s

Execute StatePlusT monad returning resulting state

evalStatePlusT :: Monad m => StatePlusT s m a -> s -> m (Maybe a)

Evaluate StatePlusT monad returning resulting value. See above for the semantics.