Safe Haskell	None
Language	Haskell2010

Control.Effect.Alt

Contents

Effects
Interpretations
Simple variants of interpretations
Threading constraints
Carriers

Synopsis

data Alt m a where
- Empty :: Alt m a
- Alt :: m a -> m a -> Alt m a
class Applicative f => Alternative (f :: Type -> Type) where
- empty :: f a
- (<|>) :: f a -> f a -> f a
- some :: f a -> f [a]
- many :: f a -> f [a]
runAltMaybe :: forall m a p. (Threaders '[ErrorThreads] m p, Carrier m) => AltMaybeC m a -> m (Maybe a)
altToError :: forall e m a. Eff (Error e) m => e -> InterpretAltReifiedC m a -> m a
altToNonDet :: Eff NonDet m => AltToNonDetC m a -> m a
altToErrorSimple :: forall e m a p. (Eff (Error e) m, Threaders '[ReaderThreads] m p) => e -> InterpretAltSimpleC m a -> m a
class (forall e. Threads (ExceptT e) p) => ErrorThreads p
type AltMaybeC = CompositionC '[IntroUnderC Alt '[Catch (), Throw ()], InterpretAltC AltToErrorUnitH, ErrorC ()]
newtype InterpretAltC h m a = InterpretAltC {
- unInterpretAltC :: InterpretC h Alt m a
}
type InterpretAltReifiedC m a = forall s. ReifiesHandler s Alt m => InterpretAltC (ViaReifiedH s) m a
type AltToNonDetC = InterpretAltC AltToNonDetH
newtype InterpretAltSimpleC m a = InterpretAltSimpleC {
- unInterpretAltSimpleC :: InterpretSimpleC Alt m a
}

Effects

data Alt m a where Source #

An effect corresponding to the Alternative type class.

Effly's Alternative instance is based on this effect; by having access to Alt, you're able to use <|> and empty inside of effect handlers.

Each Alt interpreter's associated carrier has an Alternative instance based on how it interprets Alt. This means you can use an Alt interpreter to locally gain access to an Alternative instance inside of application code.

Constructors

Empty :: Alt m a
Alt :: m a -> m a -> Alt m a

class Applicative f => Alternative (f :: Type -> Type) where #

A monoid on applicative functors.

If defined, some and many should be the least solutions of the equations:

```
some v = (:) <$> v <*> many v
```
```
many v = some v <|> pure []
```

Minimal complete definition

empty, (<|>)

Methods

empty :: f a #

The identity of <|>

(<|>) :: f a -> f a -> f a infixl 3 #

An associative binary operation

some :: f a -> f [a] #

One or more.

many :: f a -> f [a] #

Zero or more.

Instances

Alternative []	Since: base-2.1
Instance details Defined in GHC.Base Methods empty :: [a] # (<\|>) :: [a] -> [a] -> [a] # some :: [a] -> [[a]] # many :: [a] -> [[a]] #
Alternative Maybe	Since: base-2.1
Instance details Defined in GHC.Base Methods empty :: Maybe a # (<\|>) :: Maybe a -> Maybe a -> Maybe a # some :: Maybe a -> Maybe [a] # many :: Maybe a -> Maybe [a] #
Alternative IO	Since: base-4.9.0.0
Instance details Defined in GHC.Base Methods empty :: IO a # (<\|>) :: IO a -> IO a -> IO a # some :: IO a -> IO [a] # many :: IO a -> IO [a] #
Alternative Concurrently
Instance details Defined in Control.Concurrent.Async Methods empty :: Concurrently a # (<\|>) :: Concurrently a -> Concurrently a -> Concurrently a # some :: Concurrently a -> Concurrently [a] # many :: Concurrently a -> Concurrently [a] #
Alternative Option	Since: base-4.9.0.0
Instance details Defined in Data.Semigroup Methods empty :: Option a # (<\|>) :: Option a -> Option a -> Option a # some :: Option a -> Option [a] # many :: Option a -> Option [a] #
Alternative ZipList	Since: base-4.11.0.0
Instance details Defined in Control.Applicative Methods empty :: ZipList a # (<\|>) :: ZipList a -> ZipList a -> ZipList a # some :: ZipList a -> ZipList [a] # many :: ZipList a -> ZipList [a] #
Alternative STM	Since: base-4.8.0.0
Instance details Defined in GHC.Conc.Sync Methods empty :: STM a # (<\|>) :: STM a -> STM a -> STM a # some :: STM a -> STM [a] # many :: STM a -> STM [a] #
Alternative ReadP	Since: base-4.6.0.0
Instance details Defined in Text.ParserCombinators.ReadP Methods empty :: ReadP a # (<\|>) :: ReadP a -> ReadP a -> ReadP a # some :: ReadP a -> ReadP [a] # many :: ReadP a -> ReadP [a] #
Alternative Seq	Since: containers-0.5.4
Instance details Defined in Data.Sequence.Internal Methods empty :: Seq a # (<\|>) :: Seq a -> Seq a -> Seq a # some :: Seq a -> Seq [a] # many :: Seq a -> Seq [a] #
Alternative P	Since: base-4.5.0.0
Instance details Defined in Text.ParserCombinators.ReadP Methods empty :: P a # (<\|>) :: P a -> P a -> P a # some :: P a -> P [a] # many :: P a -> P [a] #
Alternative (U1 :: Type -> Type)	Since: base-4.9.0.0
Instance details Defined in GHC.Generics Methods empty :: U1 a # (<\|>) :: U1 a -> U1 a -> U1 a # some :: U1 a -> U1 [a] # many :: U1 a -> U1 [a] #
MonadPlus m => Alternative (WrappedMonad m)	Since: base-2.1
Instance details Defined in Control.Applicative Methods empty :: WrappedMonad m a # (<\|>) :: WrappedMonad m a -> WrappedMonad m a -> WrappedMonad m a # some :: WrappedMonad m a -> WrappedMonad m [a] # many :: WrappedMonad m a -> WrappedMonad m [a] #
ArrowPlus a => Alternative (ArrowMonad a)	Since: base-4.6.0.0
Instance details Defined in Control.Arrow Methods empty :: ArrowMonad a a0 # (<\|>) :: ArrowMonad a a0 -> ArrowMonad a a0 -> ArrowMonad a a0 # some :: ArrowMonad a a0 -> ArrowMonad a [a0] # many :: ArrowMonad a a0 -> ArrowMonad a [a0] #
Alternative (Proxy :: Type -> Type)	Since: base-4.9.0.0
Instance details Defined in Data.Proxy Methods empty :: Proxy a # (<\|>) :: Proxy a -> Proxy a -> Proxy a # some :: Proxy a -> Proxy [a] # many :: Proxy a -> Proxy [a] #
(Functor m, Monad m) => Alternative (MaybeT m)
Instance details Defined in Control.Monad.Trans.Maybe Methods empty :: MaybeT m a # (<\|>) :: MaybeT m a -> MaybeT m a -> MaybeT m a # some :: MaybeT m a -> MaybeT m [a] # many :: MaybeT m a -> MaybeT m [a] #
Applicative m => Alternative (ListT m)
Instance details Defined in Control.Monad.Trans.List Methods empty :: ListT m a # (<\|>) :: ListT m a -> ListT m a -> ListT m a # some :: ListT m a -> ListT m [a] # many :: ListT m a -> ListT m [a] #
Alternative m => Alternative (InterpretFailSimpleC m) Source #
Instance details Defined in Control.Effect.Fail Methods empty :: InterpretFailSimpleC m a # (<\|>) :: InterpretFailSimpleC m a -> InterpretFailSimpleC m a -> InterpretFailSimpleC m a # some :: InterpretFailSimpleC m a -> InterpretFailSimpleC m [a] # many :: InterpretFailSimpleC m a -> InterpretFailSimpleC m [a] #
(Monad m, Carrier (InterpretSimpleC (Alt :: (Type -> Type) -> Type -> Type) m)) => Alternative (InterpretAltSimpleC m) Source #
Instance details Defined in Control.Effect.Alt Methods empty :: InterpretAltSimpleC m a # (<\|>) :: InterpretAltSimpleC m a -> InterpretAltSimpleC m a -> InterpretAltSimpleC m a # some :: InterpretAltSimpleC m a -> InterpretAltSimpleC m [a] # many :: InterpretAltSimpleC m a -> InterpretAltSimpleC m [a] #
Alternative f => Alternative (Rec1 f)	Since: base-4.9.0.0
Instance details Defined in GHC.Generics Methods empty :: Rec1 f a # (<\|>) :: Rec1 f a -> Rec1 f a -> Rec1 f a # some :: Rec1 f a -> Rec1 f [a] # many :: Rec1 f a -> Rec1 f [a] #
(ArrowZero a, ArrowPlus a) => Alternative (WrappedArrow a b)	Since: base-2.1
Instance details Defined in Control.Applicative Methods empty :: WrappedArrow a b a0 # (<\|>) :: WrappedArrow a b a0 -> WrappedArrow a b a0 -> WrappedArrow a b a0 # some :: WrappedArrow a b a0 -> WrappedArrow a b [a0] # many :: WrappedArrow a b a0 -> WrappedArrow a b [a0] #
Alternative f => Alternative (Ap f)	Since: base-4.12.0.0
Instance details Defined in Data.Monoid Methods empty :: Ap f a # (<\|>) :: Ap f a -> Ap f a -> Ap f a # some :: Ap f a -> Ap f [a] # many :: Ap f a -> Ap f [a] #
Alternative f => Alternative (Alt f)	Since: base-4.8.0.0
Instance details Defined in Data.Semigroup.Internal Methods empty :: Alt f a # (<\|>) :: Alt f a -> Alt f a -> Alt f a # some :: Alt f a -> Alt f [a] # many :: Alt f a -> Alt f [a] #
(Functor m, Monad m, Monoid e) => Alternative (ExceptT e m)
Instance details Defined in Control.Monad.Trans.Except Methods empty :: ExceptT e m a # (<\|>) :: ExceptT e m a -> ExceptT e m a -> ExceptT e m a # some :: ExceptT e m a -> ExceptT e m [a] # many :: ExceptT e m a -> ExceptT e m [a] #
(Monoid w, Alternative m) => Alternative (WriterT w m)
Instance details Defined in Control.Monad.Trans.Writer.Lazy Methods empty :: WriterT w m a # (<\|>) :: WriterT w m a -> WriterT w m a -> WriterT w m a # some :: WriterT w m a -> WriterT w m [a] # many :: WriterT w m a -> WriterT w m [a] #
(Functor m, MonadPlus m) => Alternative (StateT s m)
Instance details Defined in Control.Monad.Trans.State.Lazy Methods empty :: StateT s m a # (<\|>) :: StateT s m a -> StateT s m a -> StateT s m a # some :: StateT s m a -> StateT s m [a] # many :: StateT s m a -> StateT s m [a] #
Alternative m => Alternative (ReaderT r m)
Instance details Defined in Control.Monad.Trans.Reader Methods empty :: ReaderT r m a # (<\|>) :: ReaderT r m a -> ReaderT r m a -> ReaderT r m a # some :: ReaderT r m a -> ReaderT r m [a] # many :: ReaderT r m a -> ReaderT r m [a] #
(Functor m, Monad m, Error e) => Alternative (ErrorT e m)
Instance details Defined in Control.Monad.Trans.Error Methods empty :: ErrorT e m a # (<\|>) :: ErrorT e m a -> ErrorT e m a -> ErrorT e m a # some :: ErrorT e m a -> ErrorT e m [a] # many :: ErrorT e m a -> ErrorT e m [a] #
Alternative m => Alternative (IdentityT m)
Instance details Defined in Control.Monad.Trans.Identity Methods empty :: IdentityT m a # (<\|>) :: IdentityT m a -> IdentityT m a -> IdentityT m a # some :: IdentityT m a -> IdentityT m [a] # many :: IdentityT m a -> IdentityT m [a] #
(Functor m, MonadPlus m) => Alternative (StateT s m)
Instance details Defined in Control.Monad.Trans.State.Strict Methods empty :: StateT s m a # (<\|>) :: StateT s m a -> StateT s m a -> StateT s m a # some :: StateT s m a -> StateT s m [a] # many :: StateT s m a -> StateT s m [a] #
(Monoid w, Alternative m) => Alternative (WriterT w m)
Instance details Defined in Control.Monad.Trans.Writer.Strict Methods empty :: WriterT w m a # (<\|>) :: WriterT w m a -> WriterT w m a -> WriterT w m a # some :: WriterT w m a -> WriterT w m [a] # many :: WriterT w m a -> WriterT w m [a] #
(Monoid w, Functor m, MonadPlus m) => Alternative (AccumT w m)
Instance details Defined in Control.Monad.Trans.Accum Methods empty :: AccumT w m a # (<\|>) :: AccumT w m a -> AccumT w m a -> AccumT w m a # some :: AccumT w m a -> AccumT w m [a] # many :: AccumT w m a -> AccumT w m [a] #
(Functor m, MonadPlus m) => Alternative (WriterT w m)
Instance details Defined in Control.Monad.Trans.Writer.CPS Methods empty :: WriterT w m a # (<\|>) :: WriterT w m a -> WriterT w m a -> WriterT w m a # some :: WriterT w m a -> WriterT w m [a] # many :: WriterT w m a -> WriterT w m [a] #
(Functor m, MonadPlus m) => Alternative (SelectT r m)
Instance details Defined in Control.Monad.Trans.Select Methods empty :: SelectT r m a # (<\|>) :: SelectT r m a -> SelectT r m a -> SelectT r m a # some :: SelectT r m a -> SelectT r m [a] # many :: SelectT r m a -> SelectT r m [a] #
Alternative (CompositionBaseT ts m) => Alternative (CompositionC ts m) Source #
Instance details Defined in Control.Effect.Carrier.Internal.Compose Methods empty :: CompositionC ts m a # (<\|>) :: CompositionC ts m a -> CompositionC ts m a -> CompositionC ts m a # some :: CompositionC ts m a -> CompositionC ts m [a] # many :: CompositionC ts m a -> CompositionC ts m [a] #
Eff (Alt :: (Type -> Type) -> Type -> Type) m => Alternative (Effly m) Source #
Instance details Defined in Control.Effect.Internal.Effly Methods empty :: Effly m a # (<\|>) :: Effly m a -> Effly m a -> Effly m a # some :: Effly m a -> Effly m [a] # many :: Effly m a -> Effly m [a] #
Alternative m => Alternative (InterpretPrimSimpleC e m) Source #
Instance details Defined in Control.Effect.Carrier.Internal.Interpret Methods empty :: InterpretPrimSimpleC e m a # (<\|>) :: InterpretPrimSimpleC e m a -> InterpretPrimSimpleC e m a -> InterpretPrimSimpleC e m a # some :: InterpretPrimSimpleC e m a -> InterpretPrimSimpleC e m [a] # many :: InterpretPrimSimpleC e m a -> InterpretPrimSimpleC e m [a] #
Alternative m => Alternative (InterpretSimpleC e m) Source #
Instance details Defined in Control.Effect.Carrier.Internal.Interpret Methods empty :: InterpretSimpleC e m a # (<\|>) :: InterpretSimpleC e m a -> InterpretSimpleC e m a -> InterpretSimpleC e m a # some :: InterpretSimpleC e m a -> InterpretSimpleC e m [a] # many :: InterpretSimpleC e m a -> InterpretSimpleC e m [a] #
Alternative m => Alternative (RunMC m) Source #
Instance details Defined in Control.Effect.Embed Methods empty :: RunMC m a # (<\|>) :: RunMC m a -> RunMC m a -> RunMC m a # some :: RunMC m a -> RunMC m [a] # many :: RunMC m a -> RunMC m [a] #
(Monoid s, Alternative m) => Alternative (WriterLazyC s m) Source #
Instance details Defined in Control.Effect.Internal.Writer Methods empty :: WriterLazyC s m a # (<\|>) :: WriterLazyC s m a -> WriterLazyC s m a -> WriterLazyC s m a # some :: WriterLazyC s m a -> WriterLazyC s m [a] # many :: WriterLazyC s m a -> WriterLazyC s m [a] #
(Monoid s, Alternative m) => Alternative (ListenLazyC s m) Source #
Instance details Defined in Control.Effect.Internal.Writer Methods empty :: ListenLazyC s m a # (<\|>) :: ListenLazyC s m a -> ListenLazyC s m a -> ListenLazyC s m a # some :: ListenLazyC s m a -> ListenLazyC s m [a] # many :: ListenLazyC s m a -> ListenLazyC s m [a] #
(Monoid s, Alternative m) => Alternative (TellLazyC s m) Source #
Instance details Defined in Control.Effect.Internal.Writer Methods empty :: TellLazyC s m a # (<\|>) :: TellLazyC s m a -> TellLazyC s m a -> TellLazyC s m a # some :: TellLazyC s m a -> TellLazyC s m [a] # many :: TellLazyC s m a -> TellLazyC s m [a] #
MonadPlus m => Alternative (WriterC s m) Source #
Instance details Defined in Control.Effect.Internal.Writer Methods empty :: WriterC s m a # (<\|>) :: WriterC s m a -> WriterC s m a -> WriterC s m a # some :: WriterC s m a -> WriterC s m [a] # many :: WriterC s m a -> WriterC s m [a] #
MonadPlus m => Alternative (ListenC s m) Source #
Instance details Defined in Control.Effect.Internal.Writer Methods empty :: ListenC s m a # (<\|>) :: ListenC s m a -> ListenC s m a -> ListenC s m a # some :: ListenC s m a -> ListenC s m [a] # many :: ListenC s m a -> ListenC s m [a] #
MonadPlus m => Alternative (TellC s m) Source #
Instance details Defined in Control.Effect.Internal.Writer Methods empty :: TellC s m a # (<\|>) :: TellC s m a -> TellC s m a -> TellC s m a # some :: TellC s m a -> TellC s m [a] # many :: TellC s m a -> TellC s m [a] #
Alternative m => Alternative (UnliftC m) Source #
Instance details Defined in Control.Effect.Internal.Unlift Methods empty :: UnliftC m a # (<\|>) :: UnliftC m a -> UnliftC m a -> UnliftC m a # some :: UnliftC m a -> UnliftC m [a] # many :: UnliftC m a -> UnliftC m [a] #
MonadPlus m => Alternative (StateLazyC s m) Source #
Instance details Defined in Control.Effect.Internal.State Methods empty :: StateLazyC s m a # (<\|>) :: StateLazyC s m a -> StateLazyC s m a -> StateLazyC s m a # some :: StateLazyC s m a -> StateLazyC s m [a] # many :: StateLazyC s m a -> StateLazyC s m [a] #
MonadPlus m => Alternative (StateC s m) Source #
Instance details Defined in Control.Effect.Internal.State Methods empty :: StateC s m a # (<\|>) :: StateC s m a -> StateC s m a -> StateC s m a # some :: StateC s m a -> StateC s m [a] # many :: StateC s m a -> StateC s m [a] #
Alternative m => Alternative (HoistC m) Source #
Instance details Defined in Control.Effect.Internal.Regional Methods empty :: HoistC m a # (<\|>) :: HoistC m a -> HoistC m a -> HoistC m a # some :: HoistC m a -> HoistC m [a] # many :: HoistC m a -> HoistC m [a] #
Alternative m => Alternative (ReaderC i m) Source #
Instance details Defined in Control.Effect.Internal.Reader Methods empty :: ReaderC i m a # (<\|>) :: ReaderC i m a -> ReaderC i m a -> ReaderC i m a # some :: ReaderC i m a -> ReaderC i m [a] # many :: ReaderC i m a -> ReaderC i m [a] #
Alternative m => Alternative (HoistOptionC m) Source #
Instance details Defined in Control.Effect.Internal.Optional Methods empty :: HoistOptionC m a # (<\|>) :: HoistOptionC m a -> HoistOptionC m a -> HoistOptionC m a # some :: HoistOptionC m a -> HoistOptionC m [a] # many :: HoistOptionC m a -> HoistOptionC m [a] #
Alternative m => Alternative (UnwrapTopC e m) Source #
Instance details Defined in Control.Effect.Internal.Newtype Methods empty :: UnwrapTopC e m a # (<\|>) :: UnwrapTopC e m a -> UnwrapTopC e m a -> UnwrapTopC e m a # some :: UnwrapTopC e m a -> UnwrapTopC e m [a] # many :: UnwrapTopC e m a -> UnwrapTopC e m [a] #
Alternative m => Alternative (UnwrapC e m) Source #
Instance details Defined in Control.Effect.Internal.Newtype Methods empty :: UnwrapC e m a # (<\|>) :: UnwrapC e m a -> UnwrapC e m a -> UnwrapC e m a # some :: UnwrapC e m a -> UnwrapC e m [a] # many :: UnwrapC e m a -> UnwrapC e m [a] #
(Monad m, Monoid e) => Alternative (ErrorC e m) Source #
Instance details Defined in Control.Effect.Internal.Error Methods empty :: ErrorC e m a # (<\|>) :: ErrorC e m a -> ErrorC e m a -> ErrorC e m a # some :: ErrorC e m a -> ErrorC e m [a] # many :: ErrorC e m a -> ErrorC e m [a] #
(Monad m, Monoid e) => Alternative (ThrowC e m) Source #
Instance details Defined in Control.Effect.Internal.Error Methods empty :: ThrowC e m a # (<\|>) :: ThrowC e m a -> ThrowC e m a -> ThrowC e m a # some :: ThrowC e m a -> ThrowC e m [a] # many :: ThrowC e m a -> ThrowC e m [a] #
Alternative m => Alternative (BaseControlC m) Source #
Instance details Defined in Control.Effect.Internal.BaseControl Methods empty :: BaseControlC m a # (<\|>) :: BaseControlC m a -> BaseControlC m a -> BaseControlC m a # some :: BaseControlC m a -> BaseControlC m [a] # many :: BaseControlC m a -> BaseControlC m [a] #
Eff Conc m => Alternative (Concurrently m) Source #
Instance details Defined in Control.Effect.Conc Methods empty :: Concurrently m a # (<\|>) :: Concurrently m a -> Concurrently m a -> Concurrently m a # some :: Concurrently m a -> Concurrently m [a] # many :: Concurrently m a -> Concurrently m [a] #
Alternative m => Alternative (InterceptRC e m) Source #
Instance details Defined in Control.Effect.Internal.Intercept Methods empty :: InterceptRC e m a # (<\|>) :: InterceptRC e m a -> InterceptRC e m a -> InterceptRC e m a # some :: InterceptRC e m a -> InterceptRC e m [a] # many :: InterceptRC e m a -> InterceptRC e m [a] #
Alternative m => Alternative (InterpretFailC h m) Source #
Instance details Defined in Control.Effect.Fail Methods empty :: InterpretFailC h m a # (<\|>) :: InterpretFailC h m a -> InterpretFailC h m a -> InterpretFailC h m a # some :: InterpretFailC h m a -> InterpretFailC h m [a] # many :: InterpretFailC h m a -> InterpretFailC h m [a] #
Handler h (Alt :: (Type -> Type) -> Type -> Type) m => Alternative (InterpretAltC h m) Source #
Instance details Defined in Control.Effect.Alt Methods empty :: InterpretAltC h m a # (<\|>) :: InterpretAltC h m a -> InterpretAltC h m a -> InterpretAltC h m a # some :: InterpretAltC h m a -> InterpretAltC h m [a] # many :: InterpretAltC h m a -> InterpretAltC h m [a] #
(Alternative f, Alternative g) => Alternative (f :*: g)	Since: base-4.9.0.0
Instance details Defined in GHC.Generics Methods empty :: (f :: g) a # (<\|>) :: (f :: g) a -> (f :: g) a -> (f :: g) a # some :: (f :: g) a -> (f :: g) [a] # many :: (f :: g) a -> (f :: g) [a] #
(Alternative f, Alternative g) => Alternative (Product f g)	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Product Methods empty :: Product f g a # (<\|>) :: Product f g a -> Product f g a -> Product f g a # some :: Product f g a -> Product f g [a] # many :: Product f g a -> Product f g [a] #
Alternative m => Alternative (SubsumeC e m) Source #
Instance details Defined in Control.Effect.Internal Methods empty :: SubsumeC e m a # (<\|>) :: SubsumeC e m a -> SubsumeC e m a -> SubsumeC e m a # some :: SubsumeC e m a -> SubsumeC e m [a] # many :: SubsumeC e m a -> SubsumeC e m [a] #
Alternative m => Alternative (IntroC top new m) Source #
Instance details Defined in Control.Effect.Carrier.Internal.Intro Methods empty :: IntroC top new m a # (<\|>) :: IntroC top new m a -> IntroC top new m a -> IntroC top new m a # some :: IntroC top new m a -> IntroC top new m [a] # many :: IntroC top new m a -> IntroC top new m [a] #
Alternative m => Alternative (ReinterpretSimpleC e new m) Source #
Instance details Defined in Control.Effect.Carrier.Internal.Interpret Methods empty :: ReinterpretSimpleC e new m a # (<\|>) :: ReinterpretSimpleC e new m a -> ReinterpretSimpleC e new m a -> ReinterpretSimpleC e new m a # some :: ReinterpretSimpleC e new m a -> ReinterpretSimpleC e new m [a] # many :: ReinterpretSimpleC e new m a -> ReinterpretSimpleC e new m [a] #
Alternative m => Alternative (InterpretC h e m) Source #
Instance details Defined in Control.Effect.Carrier.Internal.Interpret Methods empty :: InterpretC h e m a # (<\|>) :: InterpretC h e m a -> InterpretC h e m a -> InterpretC h e m a # some :: InterpretC h e m a -> InterpretC h e m [a] # many :: InterpretC h e m a -> InterpretC h e m [a] #
Alternative m => Alternative (InterpretPrimC s e m) Source #
Instance details Defined in Control.Effect.Carrier.Internal.Interpret Methods empty :: InterpretPrimC s e m a # (<\|>) :: InterpretPrimC s e m a -> InterpretPrimC s e m a -> InterpretPrimC s e m a # some :: InterpretPrimC s e m a -> InterpretPrimC s e m [a] # many :: InterpretPrimC s e m a -> InterpretPrimC s e m [a] #
Alternative m => Alternative (UnionC l m) Source #
Instance details Defined in Control.Effect.Union Methods empty :: UnionC l m a # (<\|>) :: UnionC l m a -> UnionC l m a -> UnionC l m a # some :: UnionC l m a -> UnionC l m [a] # many :: UnionC l m a -> UnionC l m [a] #
Alternative m => Alternative (WrapC e e' m) Source #
Instance details Defined in Control.Effect.Internal.Newtype Methods empty :: WrapC e e' m a # (<\|>) :: WrapC e e' m a -> WrapC e e' m a -> WrapC e e' m a # some :: WrapC e e' m a -> WrapC e e' m [a] # many :: WrapC e e' m a -> WrapC e e' m [a] #
Alternative f => Alternative (M1 i c f)	Since: base-4.9.0.0
Instance details Defined in GHC.Generics Methods empty :: M1 i c f a # (<\|>) :: M1 i c f a -> M1 i c f a -> M1 i c f a # some :: M1 i c f a -> M1 i c f [a] # many :: M1 i c f a -> M1 i c f [a] #
(Alternative f, Applicative g) => Alternative (f :.: g)	Since: base-4.9.0.0
Instance details Defined in GHC.Generics Methods empty :: (f :.: g) a # (<\|>) :: (f :.: g) a -> (f :.: g) a -> (f :.: g) a # some :: (f :.: g) a -> (f :.: g) [a] # many :: (f :.: g) a -> (f :.: g) [a] #
(Alternative f, Applicative g) => Alternative (Compose f g)	Since: base-4.9.0.0
Instance details Defined in Data.Functor.Compose Methods empty :: Compose f g a # (<\|>) :: Compose f g a -> Compose f g a -> Compose f g a # some :: Compose f g a -> Compose f g [a] # many :: Compose f g a -> Compose f g [a] #
(Monoid w, Functor m, MonadPlus m) => Alternative (RWST r w s m)
Instance details Defined in Control.Monad.Trans.RWS.Lazy Methods empty :: RWST r w s m a # (<\|>) :: RWST r w s m a -> RWST r w s m a -> RWST r w s m a # some :: RWST r w s m a -> RWST r w s m [a] # many :: RWST r w s m a -> RWST r w s m [a] #
(Monoid w, Functor m, MonadPlus m) => Alternative (RWST r w s m)
Instance details Defined in Control.Monad.Trans.RWS.Strict Methods empty :: RWST r w s m a # (<\|>) :: RWST r w s m a -> RWST r w s m a -> RWST r w s m a # some :: RWST r w s m a -> RWST r w s m [a] # many :: RWST r w s m a -> RWST r w s m [a] #
Alternative (t (u m)) => Alternative (ComposeT t u m) Source #
Instance details Defined in Control.Effect.Carrier.Internal.Compose Methods empty :: ComposeT t u m a # (<\|>) :: ComposeT t u m a -> ComposeT t u m a -> ComposeT t u m a # some :: ComposeT t u m a -> ComposeT t u m [a] # many :: ComposeT t u m a -> ComposeT t u m [a] #
Alternative m => Alternative (ReinterpretC h e new m) Source #
Instance details Defined in Control.Effect.Carrier.Internal.Interpret Methods empty :: ReinterpretC h e new m a # (<\|>) :: ReinterpretC h e new m a -> ReinterpretC h e new m a -> ReinterpretC h e new m a # some :: ReinterpretC h e new m a -> ReinterpretC h e new m [a] # many :: ReinterpretC h e new m a -> ReinterpretC h e new m [a] #
Alternative m => Alternative (UnionizeC b m) Source #
Instance details Defined in Control.Effect.Union Methods empty :: UnionizeC b m a # (<\|>) :: UnionizeC b m a -> UnionizeC b m a -> UnionizeC b m a # some :: UnionizeC b m a -> UnionizeC b m [a] # many :: UnionizeC b m a -> UnionizeC b m [a] #
Alternative m => Alternative (ExceptionallyC eff exc m) Source #
Instance details Defined in Control.Effect.Exceptional Methods empty :: ExceptionallyC eff exc m a # (<\|>) :: ExceptionallyC eff exc m a -> ExceptionallyC eff exc m a -> ExceptionallyC eff exc m a # some :: ExceptionallyC eff exc m a -> ExceptionallyC eff exc m [a] # many :: ExceptionallyC eff exc m a -> ExceptionallyC eff exc m [a] #
Alternative m => Alternative (GainBaseControlC b z m) Source #
Instance details Defined in Control.Effect.BaseControl Methods empty :: GainBaseControlC b z m a # (<\|>) :: GainBaseControlC b z m a -> GainBaseControlC b z m a -> GainBaseControlC b z m a # some :: GainBaseControlC b z m a -> GainBaseControlC b z m [a] # many :: GainBaseControlC b z m a -> GainBaseControlC b z m [a] #

Interpretations

runAltMaybe :: forall m a p. (Threaders '[ErrorThreads] m p, Carrier m) => AltMaybeC m a -> m (Maybe a) Source #

Run an Alt effect purely, returning Nothing on an unhandled empty.

AltMaybeC has an Alternative instance based on the Alt effect it interprets.

Derivs (AltMaybeC m) = Alt ': Derivs m Prims (AltMaybeC m) = Optional ((->) ()) ': Prims m

altToError :: forall e m a. Eff (Error e) m => e -> InterpretAltReifiedC m a -> m a Source #

Transform an Alt effect into Error by describing it in terms of throw and catch, using the provided exception to act as empty.

You can use this in application code to locally get access to an Alternative instance (since InterpretAltReifiedC has an Alternative instance based on the Alt effect this interprets).

For example:

altToError (throw exc) empty = throw exc

altToError has a higher-rank type, as it makes use of InterpretAltReifiedC. This makes altToError very difficult to use partially applied. In particular, it can't be composed using ..

If performance is secondary, consider using the slower altToErrorSimple, which doesn't have a higher-rank type. However, you typically don't want to use altToErrorSimple in application code, since altToErrorSimple emits a ReaderThreads threading constraint (see Threaders).

altToNonDet :: Eff NonDet m => AltToNonDetC m a -> m a Source #

Transform an Alt effect into NonDet by describing it in terms of lose and choose.

You can use this in application code to locally get access to an Alternative instance (since AltToNonDetC has an Alternative instance based on the Alt effect this interprets).

For example:

altToNonDet empty = lose

Simple variants of interpretations

altToErrorSimple :: forall e m a p. (Eff (Error e) m, Threaders '[ReaderThreads] m p) => e -> InterpretAltSimpleC m a -> m a Source #

Transform an Alt in terms of throw and catch, by providing an exception to act as empty.

This is a less performant version of altToError that doesn't have a higher-rank type, making it much easier to use partially applied.

Unlike altToError, you typically don't want to use this in application code, since this emits a ReaderThreads threading constraint (see Threaders).

Threading constraints

class (forall e. Threads (ExceptT e) p) => ErrorThreads p Source #

ErrorThreads accepts the following primitive effects:

Regional s
Optional s (when s is a functor)
BaseControl b
Unravel p
ListenPrim s (when s is a Monoid)
WriterPrim s (when s is a Monoid)
ReaderPrim i
Mask
Bracket
Fix

Instances

(forall e. Threads (ExceptT e) p) => ErrorThreads p Source #
Instance details Defined in Control.Effect.Internal.Error

Carriers

type AltMaybeC = CompositionC '[IntroUnderC Alt '[Catch (), Throw ()], InterpretAltC AltToErrorUnitH, ErrorC ()] Source #

newtype InterpretAltC h m a Source #

Like InterpretC specialized to interpret Alt, but has Alternative and MonadPlus instances based on the interpreted Alt.

Constructors

InterpretAltC
Fields unInterpretAltC :: InterpretC h Alt m a

Instances

MonadBase b m => MonadBase b (InterpretAltC h m) Source #
Instance details Defined in Control.Effect.Alt Methods liftBase :: b α -> InterpretAltC h m α #
MonadBaseControl b m => MonadBaseControl b (InterpretAltC h m) Source #
Instance details Defined in Control.Effect.Alt Associated Types type StM (InterpretAltC h m) a :: Type # Methods liftBaseWith :: (RunInBase (InterpretAltC h m) b -> b a) -> InterpretAltC h m a # restoreM :: StM (InterpretAltC h m) a -> InterpretAltC h m a #
MonadTrans (InterpretAltC h) Source #
Instance details Defined in Control.Effect.Alt Methods lift :: Monad m => m a -> InterpretAltC h m a #
MonadTransControl (InterpretAltC h) Source #
Instance details Defined in Control.Effect.Alt Associated Types type StT (InterpretAltC h) a :: Type # Methods liftWith :: Monad m => (Run (InterpretAltC h) -> m a) -> InterpretAltC h m a # restoreT :: Monad m => m (StT (InterpretAltC h) a) -> InterpretAltC h m a #
Monad m => Monad (InterpretAltC h m) Source #
Instance details Defined in Control.Effect.Alt Methods (>>=) :: InterpretAltC h m a -> (a -> InterpretAltC h m b) -> InterpretAltC h m b # (>>) :: InterpretAltC h m a -> InterpretAltC h m b -> InterpretAltC h m b # return :: a -> InterpretAltC h m a # fail :: String -> InterpretAltC h m a #
Functor m => Functor (InterpretAltC h m) Source #
Instance details Defined in Control.Effect.Alt Methods fmap :: (a -> b) -> InterpretAltC h m a -> InterpretAltC h m b # (<$) :: a -> InterpretAltC h m b -> InterpretAltC h m a #
MonadFix m => MonadFix (InterpretAltC h m) Source #
Instance details Defined in Control.Effect.Alt Methods mfix :: (a -> InterpretAltC h m a) -> InterpretAltC h m a #
MonadFail m => MonadFail (InterpretAltC h m) Source #
Instance details Defined in Control.Effect.Alt Methods fail :: String -> InterpretAltC h m a #
Applicative m => Applicative (InterpretAltC h m) Source #
Instance details Defined in Control.Effect.Alt Methods pure :: a -> InterpretAltC h m a # (<>) :: InterpretAltC h m (a -> b) -> InterpretAltC h m a -> InterpretAltC h m b # liftA2 :: (a -> b -> c) -> InterpretAltC h m a -> InterpretAltC h m b -> InterpretAltC h m c # (>) :: InterpretAltC h m a -> InterpretAltC h m b -> InterpretAltC h m b # (<*) :: InterpretAltC h m a -> InterpretAltC h m b -> InterpretAltC h m a #
MonadIO m => MonadIO (InterpretAltC h m) Source #
Instance details Defined in Control.Effect.Alt Methods liftIO :: IO a -> InterpretAltC h m a #
Handler h (Alt :: (Type -> Type) -> Type -> Type) m => Alternative (InterpretAltC h m) Source #
Instance details Defined in Control.Effect.Alt Methods empty :: InterpretAltC h m a # (<\|>) :: InterpretAltC h m a -> InterpretAltC h m a -> InterpretAltC h m a # some :: InterpretAltC h m a -> InterpretAltC h m [a] # many :: InterpretAltC h m a -> InterpretAltC h m [a] #
Handler h (Alt :: (Type -> Type) -> Type -> Type) m => MonadPlus (InterpretAltC h m) Source #
Instance details Defined in Control.Effect.Alt Methods mzero :: InterpretAltC h m a # mplus :: InterpretAltC h m a -> InterpretAltC h m a -> InterpretAltC h m a #
MonadThrow m => MonadThrow (InterpretAltC h m) Source #
Instance details Defined in Control.Effect.Alt Methods throwM :: Exception e => e -> InterpretAltC h m a #
MonadCatch m => MonadCatch (InterpretAltC h m) Source #
Instance details Defined in Control.Effect.Alt Methods catch :: Exception e => InterpretAltC h m a -> (e -> InterpretAltC h m a) -> InterpretAltC h m a #
MonadMask m => MonadMask (InterpretAltC h m) Source #
Instance details Defined in Control.Effect.Alt Methods mask :: ((forall a. InterpretAltC h m a -> InterpretAltC h m a) -> InterpretAltC h m b) -> InterpretAltC h m b # uninterruptibleMask :: ((forall a. InterpretAltC h m a -> InterpretAltC h m a) -> InterpretAltC h m b) -> InterpretAltC h m b # generalBracket :: InterpretAltC h m a -> (a -> ExitCase b -> InterpretAltC h m c) -> (a -> InterpretAltC h m b) -> InterpretAltC h m (b, c) #
Handler h (Alt :: (Type -> Type) -> Type -> Type) m => Carrier (InterpretAltC h m) Source #
Instance details Defined in Control.Effect.Alt Associated Types type Derivs (InterpretAltC h m) :: [Effect] Source # type Prims (InterpretAltC h m) :: [Effect] Source # Methods algPrims :: Algebra' (Prims (InterpretAltC h m)) (InterpretAltC h m) a Source # reformulate :: Monad z => Reformulation' (Derivs (InterpretAltC h m)) (Prims (InterpretAltC h m)) (InterpretAltC h m) z a Source # algDerivs :: Algebra' (Derivs (InterpretAltC h m)) (InterpretAltC h m) a Source #
type StT (InterpretAltC h) a Source #
Instance details Defined in Control.Effect.Alt type StT (InterpretAltC h) a = StT (InterpretC h (Alt :: (Type -> Type) -> Type -> Type)) a
type Derivs (InterpretAltC h m) Source #
Instance details Defined in Control.Effect.Alt type Derivs (InterpretAltC h m) = Derivs (InterpretC h (Alt :: (Type -> Type) -> Type -> Type) m)
type Prims (InterpretAltC h m) Source #
Instance details Defined in Control.Effect.Alt type Prims (InterpretAltC h m) = Prims (InterpretC h (Alt :: (Type -> Type) -> Type -> Type) m)
type StM (InterpretAltC h m) a Source #
Instance details Defined in Control.Effect.Alt type StM (InterpretAltC h m) a = StM (InterpretC h (Alt :: (Type -> Type) -> Type -> Type) m) a

type InterpretAltReifiedC m a = forall s. ReifiesHandler s Alt m => InterpretAltC (ViaReifiedH s) m a Source #

type AltToNonDetC = InterpretAltC AltToNonDetH Source #

newtype InterpretAltSimpleC m a Source #

Constructors

InterpretAltSimpleC
Fields unInterpretAltSimpleC :: InterpretSimpleC Alt m a

Instances

MonadTrans InterpretAltSimpleC Source #
Instance details Defined in Control.Effect.Alt Methods lift :: Monad m => m a -> InterpretAltSimpleC m a #
MonadBase b m => MonadBase b (InterpretAltSimpleC m) Source #
Instance details Defined in Control.Effect.Alt Methods liftBase :: b α -> InterpretAltSimpleC m α #
MonadBaseControl b m => MonadBaseControl b (InterpretAltSimpleC m) Source #
Instance details Defined in Control.Effect.Alt Associated Types type StM (InterpretAltSimpleC m) a :: Type # Methods liftBaseWith :: (RunInBase (InterpretAltSimpleC m) b -> b a) -> InterpretAltSimpleC m a # restoreM :: StM (InterpretAltSimpleC m) a -> InterpretAltSimpleC m a #
Monad m => Monad (InterpretAltSimpleC m) Source #
Instance details Defined in Control.Effect.Alt Methods (>>=) :: InterpretAltSimpleC m a -> (a -> InterpretAltSimpleC m b) -> InterpretAltSimpleC m b # (>>) :: InterpretAltSimpleC m a -> InterpretAltSimpleC m b -> InterpretAltSimpleC m b # return :: a -> InterpretAltSimpleC m a # fail :: String -> InterpretAltSimpleC m a #
Functor m => Functor (InterpretAltSimpleC m) Source #
Instance details Defined in Control.Effect.Alt Methods fmap :: (a -> b) -> InterpretAltSimpleC m a -> InterpretAltSimpleC m b # (<$) :: a -> InterpretAltSimpleC m b -> InterpretAltSimpleC m a #
MonadFix m => MonadFix (InterpretAltSimpleC m) Source #
Instance details Defined in Control.Effect.Alt Methods mfix :: (a -> InterpretAltSimpleC m a) -> InterpretAltSimpleC m a #
MonadFail m => MonadFail (InterpretAltSimpleC m) Source #
Instance details Defined in Control.Effect.Alt Methods fail :: String -> InterpretAltSimpleC m a #
Applicative m => Applicative (InterpretAltSimpleC m) Source #
Instance details Defined in Control.Effect.Alt Methods pure :: a -> InterpretAltSimpleC m a # (<>) :: InterpretAltSimpleC m (a -> b) -> InterpretAltSimpleC m a -> InterpretAltSimpleC m b # liftA2 :: (a -> b -> c) -> InterpretAltSimpleC m a -> InterpretAltSimpleC m b -> InterpretAltSimpleC m c # (>) :: InterpretAltSimpleC m a -> InterpretAltSimpleC m b -> InterpretAltSimpleC m b # (<*) :: InterpretAltSimpleC m a -> InterpretAltSimpleC m b -> InterpretAltSimpleC m a #
MonadIO m => MonadIO (InterpretAltSimpleC m) Source #
Instance details Defined in Control.Effect.Alt Methods liftIO :: IO a -> InterpretAltSimpleC m a #
(Monad m, Carrier (InterpretSimpleC (Alt :: (Type -> Type) -> Type -> Type) m)) => Alternative (InterpretAltSimpleC m) Source #
Instance details Defined in Control.Effect.Alt Methods empty :: InterpretAltSimpleC m a # (<\|>) :: InterpretAltSimpleC m a -> InterpretAltSimpleC m a -> InterpretAltSimpleC m a # some :: InterpretAltSimpleC m a -> InterpretAltSimpleC m [a] # many :: InterpretAltSimpleC m a -> InterpretAltSimpleC m [a] #
(Monad m, Carrier (InterpretSimpleC (Alt :: (Type -> Type) -> Type -> Type) m)) => MonadPlus (InterpretAltSimpleC m) Source #
Instance details Defined in Control.Effect.Alt Methods mzero :: InterpretAltSimpleC m a # mplus :: InterpretAltSimpleC m a -> InterpretAltSimpleC m a -> InterpretAltSimpleC m a #
MonadThrow m => MonadThrow (InterpretAltSimpleC m) Source #
Instance details Defined in Control.Effect.Alt Methods throwM :: Exception e => e -> InterpretAltSimpleC m a #
MonadCatch m => MonadCatch (InterpretAltSimpleC m) Source #
Instance details Defined in Control.Effect.Alt Methods catch :: Exception e => InterpretAltSimpleC m a -> (e -> InterpretAltSimpleC m a) -> InterpretAltSimpleC m a #
MonadMask m => MonadMask (InterpretAltSimpleC m) Source #
Instance details Defined in Control.Effect.Alt Methods mask :: ((forall a. InterpretAltSimpleC m a -> InterpretAltSimpleC m a) -> InterpretAltSimpleC m b) -> InterpretAltSimpleC m b # uninterruptibleMask :: ((forall a. InterpretAltSimpleC m a -> InterpretAltSimpleC m a) -> InterpretAltSimpleC m b) -> InterpretAltSimpleC m b # generalBracket :: InterpretAltSimpleC m a -> (a -> ExitCase b -> InterpretAltSimpleC m c) -> (a -> InterpretAltSimpleC m b) -> InterpretAltSimpleC m (b, c) #
(Monad m, Carrier (InterpretSimpleC (Alt :: (Type -> Type) -> Type -> Type) m)) => Carrier (InterpretAltSimpleC m) Source #
Instance details Defined in Control.Effect.Alt Associated Types type Derivs (InterpretAltSimpleC m) :: [Effect] Source # type Prims (InterpretAltSimpleC m) :: [Effect] Source # Methods algPrims :: Algebra' (Prims (InterpretAltSimpleC m)) (InterpretAltSimpleC m) a Source # reformulate :: Monad z => Reformulation' (Derivs (InterpretAltSimpleC m)) (Prims (InterpretAltSimpleC m)) (InterpretAltSimpleC m) z a Source # algDerivs :: Algebra' (Derivs (InterpretAltSimpleC m)) (InterpretAltSimpleC m) a Source #
type Derivs (InterpretAltSimpleC m) Source #
Instance details Defined in Control.Effect.Alt type Derivs (InterpretAltSimpleC m) = Derivs (InterpretSimpleC (Alt :: (Type -> Type) -> Type -> Type) m)
type Prims (InterpretAltSimpleC m) Source #
Instance details Defined in Control.Effect.Alt type Prims (InterpretAltSimpleC m) = Prims (InterpretSimpleC (Alt :: (Type -> Type) -> Type -> Type) m)
type StM (InterpretAltSimpleC m) a Source #
Instance details Defined in Control.Effect.Alt type StM (InterpretAltSimpleC m) a = StM (InterpretSimpleC (Alt :: (Type -> Type) -> Type -> Type) m) a