Control.Carrier.Choose.Church

A carrier for Choose effects (nondeterminism without failure).

Under the hood, it uses a Church-encoded binary tree to avoid the problems associated with a naïve list-based implementation (see "ListT done right").

Since: 1.0.0.0

Choose carrier

runChoose :: (m b -> m b -> m b) -> (a -> m b) -> ChooseC m a -> m b

Run a Choose effect with continuations respectively interpreting <|> and pure.

runChoose fork leaf (pure a <|> b) = leaf a `fork` runChoose fork leaf b

Since: 1.0.0.0

runChooseS :: (Semigroup b, Applicative m) => (a -> m b) -> ChooseC m a -> m b

Run a Choose effect, mapping results into a Semigroup.

Since: 1.0.0.0

newtype ChooseC (m :: Type -> Type) a

A carrier for Choose effects based on Ralf Hinze’s design described in Deriving Backtracking Monad Transformers.

Since: 1.0.0.0

Constructors

ChooseC (forall b. (m b -> m b -> m b) -> (a -> m b) -> m b)

Instances

MonadTrans ChooseC

Defined in Control.Carrier.Choose.Church

Methods

lift :: Monad m => m a -> ChooseC m a

Applicative (ChooseC m)

Defined in Control.Carrier.Choose.Church

Methods

pure :: a -> ChooseC m a

(<*>) :: ChooseC m (a -> b) -> ChooseC m a -> ChooseC m b

liftA2 :: (a -> b -> c) -> ChooseC m a -> ChooseC m b -> ChooseC m c

(*>) :: ChooseC m a -> ChooseC m b -> ChooseC m b

(<*) :: ChooseC m a -> ChooseC m b -> ChooseC m a

Functor (ChooseC m)

Defined in Control.Carrier.Choose.Church

Methods

fmap :: (a -> b) -> ChooseC m a -> ChooseC m b

(<$) :: a -> ChooseC m b -> ChooseC m a

Monad (ChooseC m)

Defined in Control.Carrier.Choose.Church

Methods

(>>=) :: ChooseC m a -> (a -> ChooseC m b) -> ChooseC m b

(>>) :: ChooseC m a -> ChooseC m b -> ChooseC m b

return :: a -> ChooseC m a

MonadFail m => MonadFail (ChooseC m)

Defined in Control.Carrier.Choose.Church

Methods

fail :: String -> ChooseC m a

MonadFix m => MonadFix (ChooseC m)

Separate fixpoints are computed for each branch.

Defined in Control.Carrier.Choose.Church

Methods

mfix :: (a -> ChooseC m a) -> ChooseC m a

MonadIO m => MonadIO (ChooseC m)

Defined in Control.Carrier.Choose.Church

Methods

liftIO :: IO a -> ChooseC m a

Algebra sig m => Algebra (Choose :+: sig) (ChooseC m)

Defined in Control.Carrier.Choose.Church

Methods

alg :: forall ctx (n :: Type -> Type) a. Functor ctx => Handler ctx n (ChooseC m) -> (Choose :+: sig) n a -> ctx () -> ChooseC m (ctx a)

Choose effect

module Control.Effect.Choose