Safe Haskell	None
Language	Haskell2010

Control.Effect.Cut

Contents

Cut effect
Cut carrier
Re-exports

Synopsis

data Cut m k
- = Cutfail
- | Call (m a) (a -> m k)
cutfail :: (Carrier sig m, Member Cut sig) => m a
call :: (Carrier sig m, Member Cut sig) => m a -> m a
cut :: (Alternative m, Carrier sig m, Member Cut sig) => m ()
runCut :: Alternative m => CutC m a -> m a
runCutAll :: (Alternative f, Applicative m) => CutC m a -> m (f a)
newtype CutC m a = CutC {
- runCutC :: forall b. (a -> m b -> m b) -> m b -> m b -> m b
}
class (HFunctor sig, Monad m) => Carrier sig m | m -> sig
class Member (sub :: (* -> *) -> * -> *) sup
run :: PureC a -> a

Cut effect

data Cut m k Source #

Cut effects are used with NonDet to provide control over backtracking.

Constructors

Cutfail
Call (m a) (a -> m k)

Instances

Effect Cut Source #
Instance details Defined in Control.Effect.Cut Methods handle :: (Functor f, Monad m) => f () -> (forall x. f (m x) -> n (f x)) -> Cut m a -> Cut n (f a) Source #
HFunctor Cut Source #
Instance details Defined in Control.Effect.Cut Methods fmap' :: Functor (Cut f) => (a -> b) -> Cut f a -> Cut f b Source # hmap :: Functor m => (forall x. m x -> n x) -> Cut m a -> Cut n a Source #
Functor m => Functor (Cut m) Source #
Instance details Defined in Control.Effect.Cut Methods fmap :: (a -> b) -> Cut m a -> Cut m b # (<$) :: a -> Cut m b -> Cut m a #
(Carrier sig m, Effect sig) => Carrier (Cut :+: (NonDet :+: sig)) (CutC m) Source #
Instance details Defined in Control.Effect.Cut Methods eff :: (Cut :+: (NonDet :+: sig)) (CutC m) a -> CutC m a Source #

cutfail :: (Carrier sig m, Member Cut sig) => m a Source #

Fail the current branch, and prevent backtracking within the nearest enclosing call (if any).

Contrast with empty, which fails the current branch but allows backtracking.

run (runNonDet (runCut (cutfail <|> pure a))) === []

run (runNonDet (runCut (pure a <|> cutfail))) === [a]

call :: (Carrier sig m, Member Cut sig) => m a -> m a Source #

Delimit the effect of cutfails, allowing backtracking to resume.

run (runNonDet (runCut (call (cutfail <|> pure a) <|> pure b))) === [b]

cut :: (Alternative m, Carrier sig m, Member Cut sig) => m () Source #

Commit to the current branch, preventing backtracking within the nearest enclosing call (if any) on failure.

run (runNonDet (runCut (pure a <|> cut *> pure b))) === [a, b]

run (runNonDet (runCut (cut *> pure a <|> pure b))) === [a]

run (runNonDet (runCut (cut *> empty <|> pure a))) === []

Cut carrier

runCut :: Alternative m => CutC m a -> m a Source #

Run a Cut effect within an underlying Alternative instance (typically another Carrier for a NonDet effect).

run (runNonDetOnce (runCut (pure a))) === Just a

runCutAll :: (Alternative f, Applicative m) => CutC m a -> m (f a) Source #

Run a Cut effect, returning all its results in an Alternative collection.

newtype CutC m a Source #

Constructors

CutC
Fields runCutC :: forall b. (a -> m b -> m b) -> m b -> m b -> m b A higher-order function receiving three parameters: a function to combine each solution with the rest of the solutions, an action to run when no results are produced (e.g. on `empty`), and an action to run when no results are produced and backtrcking should not be attempted (e.g. on `cutfail`).

Instances

MonadTrans CutC Source #
Instance details Defined in Control.Effect.Cut Methods lift :: Monad m => m a -> CutC m a #
Monad (CutC m) Source #
Instance details Defined in Control.Effect.Cut Methods (>>=) :: CutC m a -> (a -> CutC m b) -> CutC m b # (>>) :: CutC m a -> CutC m b -> CutC m b # return :: a -> CutC m a # fail :: String -> CutC m a #
Functor (CutC m) Source #
Instance details Defined in Control.Effect.Cut Methods fmap :: (a -> b) -> CutC m a -> CutC m b # (<$) :: a -> CutC m b -> CutC m a #
MonadFix m => MonadFix (CutC m) Source #
Instance details Defined in Control.Effect.Cut Methods mfix :: (a -> CutC m a) -> CutC m a #
MonadFail m => MonadFail (CutC m) Source #
Instance details Defined in Control.Effect.Cut Methods fail :: String -> CutC m a #
Applicative (CutC m) Source #
Instance details Defined in Control.Effect.Cut Methods pure :: a -> CutC m a # (<>) :: CutC m (a -> b) -> CutC m a -> CutC m b # liftA2 :: (a -> b -> c) -> CutC m a -> CutC m b -> CutC m c # (>) :: CutC m a -> CutC m b -> CutC m b # (<*) :: CutC m a -> CutC m b -> CutC m a #
MonadIO m => MonadIO (CutC m) Source #
Instance details Defined in Control.Effect.Cut Methods liftIO :: IO a -> CutC m a #
Alternative (CutC m) Source #
Instance details Defined in Control.Effect.Cut Methods empty :: CutC m a # (<\|>) :: CutC m a -> CutC m a -> CutC m a # some :: CutC m a -> CutC m [a] # many :: CutC m a -> CutC m [a] #
MonadPlus (CutC m) Source #
Instance details Defined in Control.Effect.Cut Methods mzero :: CutC m a # mplus :: CutC m a -> CutC m a -> CutC m a #
(Carrier sig m, Effect sig) => Carrier (Cut :+: (NonDet :+: sig)) (CutC m) Source #
Instance details Defined in Control.Effect.Cut Methods eff :: (Cut :+: (NonDet :+: sig)) (CutC m) a -> CutC m a Source #

Re-exports

class (HFunctor sig, Monad m) => Carrier sig m | m -> sig Source #

The class of carriers (results) for algebras (effect handlers) over signatures (effects), whose actions are given by the eff method.

Minimal complete definition

eff

Instances

Carrier Pure PureC Source #
Instance details Defined in Control.Effect.Carrier Methods eff :: Pure PureC a -> PureC a Source #
(HFunctor eff, Carrier sig m, Member eff sig) => Carrier sig (InterposeC eff m) Source #
Instance details Defined in Control.Effect.Interpose Methods eff :: sig (InterposeC eff m) a -> InterposeC eff m a Source #
Monad m => Carrier (Lift m) (LiftC m) Source #
Instance details Defined in Control.Effect.Lift Methods eff :: Lift m (LiftC m) a -> LiftC m a Source #
(Carrier sig m, MonadIO m) => Carrier (Resource :+: sig) (ResourceC m) Source #
Instance details Defined in Control.Effect.Resource Methods eff :: (Resource :+: sig) (ResourceC m) a -> ResourceC m a Source #
(Carrier sig m, Effect sig) => Carrier (NonDet :+: sig) (NonDetC m) Source #
Instance details Defined in Control.Effect.NonDet Methods eff :: (NonDet :+: sig) (NonDetC m) a -> NonDetC m a Source #
(Carrier sig m, Effect sig) => Carrier (NonDet :+: sig) (OnceC m) Source #
Instance details Defined in Control.Effect.Cull Methods eff :: (NonDet :+: sig) (OnceC m) a -> OnceC m a Source #
(Carrier sig m, Effect sig) => Carrier (Fresh :+: sig) (FreshC m) Source #
Instance details Defined in Control.Effect.Fresh Methods eff :: (Fresh :+: sig) (FreshC m) a -> FreshC m a Source #
(Carrier sig m, Effect sig) => Carrier (Fail :+: sig) (FailC m) Source #
Instance details Defined in Control.Effect.Fail Methods eff :: (Fail :+: sig) (FailC m) a -> FailC m a Source #
(Carrier sig m, Effect sig) => Carrier (Cut :+: (NonDet :+: sig)) (CutC m) Source #
Instance details Defined in Control.Effect.Cut Methods eff :: (Cut :+: (NonDet :+: sig)) (CutC m) a -> CutC m a Source #
(Carrier sig m, Effect sig) => Carrier (Cull :+: (NonDet :+: sig)) (CullC m) Source #
Instance details Defined in Control.Effect.Cull Methods eff :: (Cull :+: (NonDet :+: sig)) (CullC m) a -> CullC m a Source #
(Carrier sig m, Effect sig) => Carrier (Trace :+: sig) (TraceByReturningC m) Source #
Instance details Defined in Control.Effect.Trace Methods eff :: (Trace :+: sig) (TraceByReturningC m) a -> TraceByReturningC m a Source #
Carrier sig m => Carrier (Trace :+: sig) (TraceByIgnoringC m) Source #
Instance details Defined in Control.Effect.Trace Methods eff :: (Trace :+: sig) (TraceByIgnoringC m) a -> TraceByIgnoringC m a Source #
(MonadIO m, Carrier sig m) => Carrier (Trace :+: sig) (TraceByPrintingC m) Source #
Instance details Defined in Control.Effect.Trace Methods eff :: (Trace :+: sig) (TraceByPrintingC m) a -> TraceByPrintingC m a Source #
(HFunctor eff, Carrier sig m) => Carrier (eff :+: sig) (InterpretC eff m) Source #
Instance details Defined in Control.Effect.Interpret Methods eff :: (eff :+: sig) (InterpretC eff m) a -> InterpretC eff m a Source #
(Carrier sig m, Effect sig) => Carrier (State s :+: sig) (StateC s m) Source #
Instance details Defined in Control.Effect.State.Strict Methods eff :: (State s :+: sig) (StateC s m) a -> StateC s m a Source #
(Carrier sig m, Effect sig) => Carrier (State s :+: sig) (StateC s m) Source #
Instance details Defined in Control.Effect.State.Lazy Methods eff :: (State s :+: sig) (StateC s m) a -> StateC s m a Source #
Carrier sig m => Carrier (Reader r :+: sig) (ReaderC r m) Source #
Instance details Defined in Control.Effect.Reader Methods eff :: (Reader r :+: sig) (ReaderC r m) a -> ReaderC r m a Source #
(Carrier sig m, Effect sig, RandomGen g) => Carrier (Random :+: sig) (RandomC g m) Source #
Instance details Defined in Control.Effect.Random Methods eff :: (Random :+: sig) (RandomC g m) a -> RandomC g m a Source #
(Carrier sig m, Effect sig) => Carrier (Error e :+: sig) (ErrorC e m) Source #
Instance details Defined in Control.Effect.Error Methods eff :: (Error e :+: sig) (ErrorC e m) a -> ErrorC e m a Source #
Carrier sig m => Carrier (Resumable err :+: sig) (ResumableWithC err m) Source #
Instance details Defined in Control.Effect.Resumable Methods eff :: (Resumable err :+: sig) (ResumableWithC err m) a -> ResumableWithC err m a Source #
(Carrier sig m, Effect sig) => Carrier (Resumable err :+: sig) (ResumableC err m) Source #
Instance details Defined in Control.Effect.Resumable Methods eff :: (Resumable err :+: sig) (ResumableC err m) a -> ResumableC err m a Source #
(Monoid w, Carrier sig m, Effect sig) => Carrier (Writer w :+: sig) (WriterC w m) Source #
Instance details Defined in Control.Effect.Writer Methods eff :: (Writer w :+: sig) (WriterC w m) a -> WriterC w m a Source #
(HFunctor eff, Carrier sig m, Effect sig) => Carrier (eff :+: sig) (InterpretStateC eff s m) Source #
Instance details Defined in Control.Effect.Interpret Methods eff :: (eff :+: sig) (InterpretStateC eff s m) a -> InterpretStateC eff s m a Source #

class Member (sub :: (* -> *) -> * -> *) sup Source #

Minimal complete definition

inj, prj

Instances

Member sub sub Source #
Instance details Defined in Control.Effect.Sum Methods inj :: sub m a -> sub m a Source # prj :: sub m a -> Maybe (sub m a) Source #
Member sub sup => Member sub (sub' :+: sup) Source #
Instance details Defined in Control.Effect.Sum Methods inj :: sub m a -> (sub' :+: sup) m a Source # prj :: (sub' :+: sup) m a -> Maybe (sub m a) Source #
Member sub (sub :+: sup) Source #
Instance details Defined in Control.Effect.Sum Methods inj :: sub m a -> (sub :+: sup) m a Source # prj :: (sub :+: sup) m a -> Maybe (sub m a) Source #

run :: PureC a -> a Source #

Run an action exhausted of effects to produce its final result value.