Safe Haskell	None
Language	Haskell2010

Control.Effect.Choose

Contents

Choose effect
Choosing semigroup
Re-exports

Description

An effect modelling nondeterminism without failure (one or more successful results).

The NonDet effect is the composition of Choose and Empty.

Predefined carriers:

Control.Carrier.Choose.Church.
If Choose is the last effect in a stack, it can be interpreted directly to a NonEmpty.

Since: 1.0.0.0

Synopsis

newtype Choose m k = Choose (Bool -> m k)
(<|>) :: Has Choose sig m => m a -> m a -> m a
optional :: Has Choose sig m => m a -> m (Maybe a)
many :: Has Choose sig m => m a -> m [a]
some :: Has Choose sig m => m a -> m [a]
some1 :: Has Choose sig m => m a -> m (NonEmpty a)
newtype Choosing m a = Choosing {
- getChoosing :: m a
}
class (HFunctor sig, Monad m) => Algebra sig m | m -> sig
type Has eff sig m = (Members eff sig, Algebra sig m)
run :: Identity a -> a

Choose effect

newtype Choose m k Source #

Since: 1.0.0.0

Constructors

Choose (Bool -> m k)

Instances

Effect Choose Source #
Instance details Defined in Control.Effect.Choose.Internal Methods thread :: (Functor ctx, Monad m) => ctx () -> (forall x. ctx (m x) -> n (ctx x)) -> Choose m a -> Choose n (ctx a) Source #
HFunctor Choose Source #
Instance details Defined in Control.Effect.Choose.Internal Methods hmap :: Functor m => (forall x. m x -> n x) -> Choose m a -> Choose n a Source #
Algebra Choose NonEmpty Source #
Instance details Defined in Control.Algebra Methods alg :: Choose NonEmpty a -> NonEmpty a Source #
Algebra NonDet [] Source #
Instance details Defined in Control.Algebra Methods alg :: NonDet [] a -> [a] Source #
Functor m => Functor (Choose m) Source #
Instance details Defined in Control.Effect.Choose.Internal Methods fmap :: (a -> b) -> Choose m a -> Choose m b # (<$) :: a -> Choose m b -> Choose m a #
Generic1 (Choose m :: Type -> Type) Source #
Instance details Defined in Control.Effect.Choose.Internal Associated Types type Rep1 (Choose m) :: k -> Type # Methods from1 :: Choose m a -> Rep1 (Choose m) a # to1 :: Rep1 (Choose m) a -> Choose m a #
(Algebra sig m, Effect sig) => Algebra (Choose :+: sig) (ChooseC m) Source #
Instance details Defined in Control.Carrier.Choose.Church Methods alg :: (Choose :+: sig) (ChooseC m) a -> ChooseC m a Source #
(Algebra sig m, Effect sig) => Algebra (NonDet :+: sig) (NonDetC m) Source #
Instance details Defined in Control.Carrier.NonDet.Church Methods alg :: (NonDet :+: sig) (NonDetC m) a -> NonDetC m a Source #
(Algebra sig m, Effect sig) => Algebra (Cut :+: (NonDet :+: sig)) (CutC m) Source #
Instance details Defined in Control.Carrier.Cut.Church Methods alg :: (Cut :+: (NonDet :+: sig)) (CutC m) a -> CutC m a Source #
(Algebra sig m, Effect sig) => Algebra (Cull :+: (NonDet :+: sig)) (CullC m) Source #
Instance details Defined in Control.Carrier.Cull.Church Methods alg :: (Cull :+: (NonDet :+: sig)) (CullC m) a -> CullC m a Source #
type Rep1 (Choose m :: Type -> Type) Source #
Instance details Defined in Control.Effect.Choose.Internal type Rep1 (Choose m :: Type -> Type) = D1 (MetaData "Choose" "Control.Effect.Choose.Internal" "fused-effects-1.0.0.0-inplace" True) (C1 (MetaCons "Choose" PrefixI False) (S1 (MetaSel (Nothing :: Maybe Symbol) NoSourceUnpackedness NoSourceStrictness DecidedLazy) (((->) Bool :: Type -> Type) :.: Rec1 m)))

(<|>) :: Has Choose sig m => m a -> m a -> m a infixl 3 Source #

Nondeterministically choose between two computations.

(m <|> n) >>= k = (m >>= k) <|> (n >>= k)

(m <|> n) <|> o = m <|> (n <|> o)

empty <|> m = m

m <|> empty = m

Since: 1.0.0.0

optional :: Has Choose sig m => m a -> m (Maybe a) Source #

Select between Just the result of an operation, and Nothing.

optional empty = pure Nothing

optional (pure a) = pure (Just a)

Since: 1.0.0.0

many :: Has Choose sig m => m a -> m [a] Source #

Zero or more.

many m = some m <|> pure []

Since: 1.0.0.0

some :: Has Choose sig m => m a -> m [a] Source #

One or more.

some m = (:) <$> m <*> many m

Since: 1.0.0.0

some1 :: Has Choose sig m => m a -> m (NonEmpty a) Source #

One or more, returning a NonEmpty list of the results.

some1 m = (:|) <$> m <*> many m

Since: 1.0.0.0

Choosing semigroup

newtype Choosing m a Source #

Since: 1.0.0.0

Constructors

Choosing
Fields getChoosing :: m a

Instances

Has Choose sig m => Semigroup (Choosing m a) Source #
Instance details Defined in Control.Effect.Choose Methods (<>) :: Choosing m a -> Choosing m a -> Choosing m a # sconcat :: NonEmpty (Choosing m a) -> Choosing m a # stimes :: Integral b => b -> Choosing m a -> Choosing m a #
(Has Choose sig m, Has Empty sig m) => Monoid (Choosing m a) Source #
Instance details Defined in Control.Effect.Choose Methods mempty :: Choosing m a # mappend :: Choosing m a -> Choosing m a -> Choosing m a # mconcat :: [Choosing m a] -> Choosing m a #

Re-exports

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

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

Since: 1.0.0.0

Minimal complete definition

alg

Instances

Algebra Choose NonEmpty Source #
Instance details Defined in Control.Algebra Methods alg :: Choose NonEmpty a -> NonEmpty a Source #
Algebra Empty Maybe Source #
Instance details Defined in Control.Algebra Methods alg :: Empty Maybe a -> Maybe a Source #
Algebra NonDet [] Source #
Instance details Defined in Control.Algebra Methods alg :: NonDet [] a -> [a] Source #
Algebra sig m => Algebra sig (IdentityT m) Source #
Instance details Defined in Control.Algebra Methods alg :: sig (IdentityT m) a -> IdentityT m a Source #
Algebra (Lift IO) IO Source #
Instance details Defined in Control.Algebra Methods alg :: Lift IO IO a -> IO a Source #
Algebra (Lift Identity) Identity Source #
Instance details Defined in Control.Algebra Methods alg :: Lift Identity Identity a -> Identity a Source #
Monad m => Algebra (Lift m) (LiftC m) Source #
Instance details Defined in Control.Carrier.Lift Methods alg :: Lift m (LiftC m) a -> LiftC m a Source #
Algebra (Error e) (Either e) Source #
Instance details Defined in Control.Algebra Methods alg :: Error e (Either e) a -> Either e a Source #
Monoid w => Algebra (Writer w) ((,) w) Source #
Instance details Defined in Control.Algebra Methods alg :: Writer w ((,) w) a -> (w, a) Source #
Algebra (Reader r) ((->) r :: Type -> Type) Source #
Instance details Defined in Control.Algebra Methods alg :: Reader r ((->) r) a -> r -> a Source #
(Algebra sig m, Effect sig) => Algebra (Choose :+: sig) (ChooseC m) Source #
Instance details Defined in Control.Carrier.Choose.Church Methods alg :: (Choose :+: sig) (ChooseC m) a -> ChooseC m a Source #
(Algebra sig m, Effect sig) => Algebra (Empty :+: sig) (EmptyC m) Source #
Instance details Defined in Control.Carrier.Empty.Maybe Methods alg :: (Empty :+: sig) (EmptyC m) a -> EmptyC m a Source #
(Algebra sig m, Effect sig) => Algebra (NonDet :+: sig) (NonDetC m) Source #
Instance details Defined in Control.Carrier.NonDet.Church Methods alg :: (NonDet :+: sig) (NonDetC m) a -> NonDetC m a Source #
(MonadIO m, Algebra sig m) => Algebra (Trace :+: sig) (TraceC m) Source #
Instance details Defined in Control.Carrier.Trace.Printing Methods alg :: (Trace :+: sig) (TraceC m) a -> TraceC m a Source #
Algebra sig m => Algebra (Trace :+: sig) (TraceC m) Source #
Instance details Defined in Control.Carrier.Trace.Ignoring Methods alg :: (Trace :+: sig) (TraceC m) a -> TraceC m a Source #
(Algebra sig m, Effect sig) => Algebra (Trace :+: sig) (TraceC m) Source #
Instance details Defined in Control.Carrier.Trace.Returning Methods alg :: (Trace :+: sig) (TraceC m) a -> TraceC m a Source #
(Algebra sig m, Effect sig) => Algebra (Fail :+: sig) (FailC m) Source #
Instance details Defined in Control.Carrier.Fail.Either Methods alg :: (Fail :+: sig) (FailC m) a -> FailC m a Source #
(Algebra sig m, Effect sig) => Algebra (Fresh :+: sig) (FreshC m) Source #
Instance details Defined in Control.Carrier.Fresh.Strict Methods alg :: (Fresh :+: sig) (FreshC m) a -> FreshC m a Source #
(Algebra sig m, Effect sig) => Algebra (Cut :+: (NonDet :+: sig)) (CutC m) Source #
Instance details Defined in Control.Carrier.Cut.Church Methods alg :: (Cut :+: (NonDet :+: sig)) (CutC m) a -> CutC m a Source #
(Algebra sig m, Effect sig) => Algebra (Cull :+: (NonDet :+: sig)) (CullC m) Source #
Instance details Defined in Control.Carrier.Cull.Church Methods alg :: (Cull :+: (NonDet :+: sig)) (CullC m) a -> CullC m a Source #
Algebra sig m => Algebra (Reader r :+: sig) (ReaderT r m) Source #
Instance details Defined in Control.Algebra Methods alg :: (Reader r :+: sig) (ReaderT r m) a -> ReaderT r m a Source #
Algebra sig m => Algebra (Reader r :+: sig) (ReaderC r m) Source #
Instance details Defined in Control.Carrier.Reader Methods alg :: (Reader r :+: sig) (ReaderC r m) a -> ReaderC r m a Source #
(Algebra sig m, Effect sig) => Algebra (State s :+: sig) (StateT s m) Source #
Instance details Defined in Control.Algebra Methods alg :: (State s :+: sig) (StateT s m) a -> StateT s m a Source #
(Algebra sig m, Effect sig) => Algebra (State s :+: sig) (StateT s m) Source #
Instance details Defined in Control.Algebra Methods alg :: (State s :+: sig) (StateT s m) a -> StateT s m a Source #
(Algebra sig m, Effect sig) => Algebra (State s :+: sig) (StateC s m) Source #
Instance details Defined in Control.Carrier.State.Strict Methods alg :: (State s :+: sig) (StateC s m) a -> StateC s m a Source #
(Algebra sig m, Effect sig) => Algebra (State s :+: sig) (StateC s m) Source #
Instance details Defined in Control.Carrier.State.Lazy Methods alg :: (State s :+: sig) (StateC s m) a -> StateC s m a Source #
(Algebra sig m, Effect sig) => Algebra (Throw e :+: sig) (ThrowC e m) Source #
Instance details Defined in Control.Carrier.Throw.Either Methods alg :: (Throw e :+: sig) (ThrowC e m) a -> ThrowC e m a Source #
(Algebra sig m, Effect sig) => Algebra (Error e :+: sig) (ExceptT e m) Source #
Instance details Defined in Control.Algebra Methods alg :: (Error e :+: sig) (ExceptT e m) a -> ExceptT e m a Source #
(Algebra sig m, Effect sig) => Algebra (Error e :+: sig) (ErrorC e m) Source #
Instance details Defined in Control.Carrier.Error.Either Methods alg :: (Error e :+: sig) (ErrorC e m) a -> ErrorC e m a Source #
(Algebra sig m, Effect sig, Monoid w) => Algebra (Writer w :+: sig) (WriterT w m) Source #
Instance details Defined in Control.Algebra Methods alg :: (Writer w :+: sig) (WriterT w m) a -> WriterT w m a Source #
(Algebra sig m, Effect sig, Monoid w) => Algebra (Writer w :+: sig) (WriterT w m) Source #
Instance details Defined in Control.Algebra Methods alg :: (Writer w :+: sig) (WriterT w m) a -> WriterT w m a Source #
(Monoid w, Algebra sig m, Effect sig) => Algebra (Writer w :+: sig) (WriterC w m) Source #
Instance details Defined in Control.Carrier.Writer.Strict Methods alg :: (Writer w :+: sig) (WriterC w m) a -> WriterC w m a Source #
(HFunctor eff, HFunctor sig, Reifies s (Handler eff m), Monad m, Algebra sig m) => Algebra (eff :+: sig) (InterpretC s eff m) Source #
Instance details Defined in Control.Carrier.Interpret Methods alg :: (eff :+: sig) (InterpretC s eff m) a -> InterpretC s eff m a Source #
(Algebra sig m, Effect sig, Monoid w) => Algebra (Reader r :+: (Writer w :+: (State s :+: sig))) (RWST r w s m) Source #
Instance details Defined in Control.Algebra Methods alg :: (Reader r :+: (Writer w :+: (State s :+: sig))) (RWST r w s m) a -> RWST r w s m a Source #
(Algebra sig m, Effect sig, Monoid w) => Algebra (Reader r :+: (Writer w :+: (State s :+: sig))) (RWST r w s m) Source #
Instance details Defined in Control.Algebra Methods alg :: (Reader r :+: (Writer w :+: (State s :+: sig))) (RWST r w s m) a -> RWST r w s m a Source #

type Has eff sig m = (Members eff sig, Algebra sig m) Source #

m is a carrier for sig containing eff.

Note that if eff is a sum, it will be decomposed into multiple Member constraints. While this technically allows one to combine multiple unrelated effects into a single Has constraint, doing so has two significant drawbacks:

Due to a problem with recursive type families, this can lead to significantly slower compiles.
It defeats ghc’s warnings for redundant constraints, and thus can lead to a proliferation of redundant constraints as code is changed.

run :: Identity a -> a Source #

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

Since: 1.0.0.0