Control.Carrier.NonDet.Church

Provides NonDetC, a carrier for NonDet effects providing choice and failure.

Under the hood, it uses a Church-encoded structure and a binary tree to prevent the problems associated with a naïve list-based implementation.

Since: 1.0.0.0

NonDet carrier

runNonDet

Arguments

:: (m b -> m b -> m b)

Handles choice (<|>)

-> (a -> m b)

Handles embedding results (pure)

-> m b

Handles failure (empty)

-> NonDetC m a

A nondeterministic computation to execute

-> m b

Run a NonDet effect, using the provided functions to interpret choice, leaf results, and failure.

runNonDet fork leaf nil (pure a <|> empty) = leaf a `fork` nil

Since: 1.0.0.0

runNonDetA :: (Alternative f, Applicative m) => NonDetC m a -> m (f a)

Run a NonDet effect, collecting all branches’ results into an Alternative functor.

Using [] as the Alternative functor will produce all results, while Maybe will return only the first. However, unless used with cull, this will still enumerate the entire search space before returning, meaning that it will diverge for infinite search spaces, even when using Maybe.

runNonDetA (pure a) = pure [a]

runNonDetA (pure a) = pure (Just a)

Since: 1.0.0.0

runNonDetM :: (Applicative m, Monoid b) => (a -> b) -> NonDetC m a -> m b

Run a NonDet effect, mapping results into a Monoid.

Since: 1.0.0.0

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

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

Since: 1.0.0.0

Constructors

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

Instances

MonadTrans NonDetC

Defined in Control.Carrier.NonDet.Church

Methods

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

MonadIO m => MonadIO (NonDetC m)

Defined in Control.Carrier.NonDet.Church

Methods

liftIO :: IO a -> NonDetC m a

Alternative (NonDetC m)

Defined in Control.Carrier.NonDet.Church

Methods

empty :: NonDetC m a

(<|>) :: NonDetC m a -> NonDetC m a -> NonDetC m a

some :: NonDetC m a -> NonDetC m [a]

many :: NonDetC m a -> NonDetC m [a]

Applicative (NonDetC m)

Defined in Control.Carrier.NonDet.Church

Methods

pure :: a -> NonDetC m a

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

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

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

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

Functor (NonDetC m)

Defined in Control.Carrier.NonDet.Church

Methods

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

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

Monad (NonDetC m)

Defined in Control.Carrier.NonDet.Church

Methods

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

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

return :: a -> NonDetC m a

MonadPlus (NonDetC m)

Defined in Control.Carrier.NonDet.Church

Methods

mzero :: NonDetC m a

mplus :: NonDetC m a -> NonDetC m a -> NonDetC m a

MonadFail m => MonadFail (NonDetC m)

Defined in Control.Carrier.NonDet.Church

Methods

fail :: String -> NonDetC m a

MonadFix m => MonadFix (NonDetC m)

Separate fixpoints are computed for each branch.

Defined in Control.Carrier.NonDet.Church

Methods

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

Algebra sig m => Algebra (NonDet :+: sig) (NonDetC m)

Defined in Control.Carrier.NonDet.Church

Methods

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

NonDet effects

module Control.Effect.NonDet