Control.Monad.Trans.Choice.Covariant

Documentation

data ChoiceT f m a

Instances

MonadRWS r w s m => MonadRWS r w s (ChoiceT f m)

Defined in Control.Monad.Trans.Choice.Covariant

MonadWriter w m => MonadWriter w (ChoiceT f m)

Defined in Control.Monad.Trans.Choice.Covariant

Methods

writer :: (a, w) -> ChoiceT f m a

tell :: w -> ChoiceT f m ()

listen :: ChoiceT f m a -> ChoiceT f m (a, w)

pass :: ChoiceT f m (a, w -> w) -> ChoiceT f m a

MonadState s m => MonadState s (ChoiceT f m)

Defined in Control.Monad.Trans.Choice.Covariant

Methods

get :: ChoiceT f m s

put :: s -> ChoiceT f m ()

state :: (s -> (a, s)) -> ChoiceT f m a

MonadReader r m => MonadReader r (ChoiceT f m)

Defined in Control.Monad.Trans.Choice.Covariant

Methods

ask :: ChoiceT f m r

local :: (r -> r) -> ChoiceT f m a -> ChoiceT f m a

reader :: (r -> a) -> ChoiceT f m a

MonadChoice f (ChoiceT f m)

Defined in Control.Monad.Trans.Choice.Covariant

Methods

choose :: f a -> ChoiceT f m a

MonadTrans (ChoiceT f)

Defined in Control.Monad.Trans.Choice.Covariant

Methods

lift :: Monad m => m a -> ChoiceT f m a

Monad (ChoiceT f m)

Defined in Control.Monad.Trans.Choice.Covariant

Methods

(>>=) :: ChoiceT f m a -> (a -> ChoiceT f m b) -> ChoiceT f m b

(>>) :: ChoiceT f m a -> ChoiceT f m b -> ChoiceT f m b

return :: a -> ChoiceT f m a

fail :: String -> ChoiceT f m a

Functor (ChoiceT f m)

Defined in Control.Monad.Trans.Choice.Covariant

Methods

fmap :: (a -> b) -> ChoiceT f m a -> ChoiceT f m b

(<$) :: a -> ChoiceT f m b -> ChoiceT f m a

Applicative (ChoiceT f m)

Defined in Control.Monad.Trans.Choice.Covariant

Methods

pure :: a -> ChoiceT f m a

(<*>) :: ChoiceT f m (a -> b) -> ChoiceT f m a -> ChoiceT f m b

liftA2 :: (a -> b -> c) -> ChoiceT f m a -> ChoiceT f m b -> ChoiceT f m c

(*>) :: ChoiceT f m a -> ChoiceT f m b -> ChoiceT f m b

(<*) :: ChoiceT f m a -> ChoiceT f m b -> ChoiceT f m a

MonadIO m => MonadIO (ChoiceT f m)

Defined in Control.Monad.Trans.Choice.Covariant

Methods

liftIO :: IO a -> ChoiceT f m a

runChoiceT :: Monad m => (forall x. f x -> m x) -> ChoiceT f m a -> m a

mapChoiceT :: (forall x. m x -> n x) -> ChoiceT f m a -> ChoiceT f n a

runBacktrackableChoiceT

Arguments

:: Monad m

=> (forall x. f x -> m (Maybe x))

The selection function. If the result of the outputted computation is Nothing then runBacktrackableChoiceT will backtrack to the previous choice. Otherwise, the result is a Just then it will proceed like runChoiceT.

-> ChoiceT f m a

The choice structure to run

-> m (Maybe a)

The resulting computation. If the selection function backtracks on the first choice the result of the computation will be Nothing.

A variant of runChoiceT that allows for the selection function to output Nothing to represent the desire to potentially select a different option for the previous choice.