semigroupoids-5.2.1: Semigroupoids: Category sans id

Data.Functor.Alt

Description

Synopsis

Documentation

class Functor f => Alt f where Source #

Laws:

<!> is associative:             (a <!> b) <!> c = a <!> (b <!> c)
<$> left-distributes over <!>: f <$> (a <!> b) = (f <$> a) <!> (f <$> b)

If extended to an Alternative then <!> should equal <|>.

Ideally, an instance of Alt also satisfies the "left distributon" law of MonadPlus with respect to <.>:

<.> right-distributes over <!>: (a <!> b) <.> c = (a <.> c) <!> (b <.> c)

But Maybe, IO, Either a, ErrorT e m, and STM satisfy the alternative "left catch" law instead:

pure a <!> b = pure a

However, this variation cannot be stated purely in terms of the dependencies of Alt.

When and if MonadPlus is successfully refactored, this class should also be refactored to remove these instances.

The right distributive law should extend in the cases where the a Bind or Monad is provided to yield variations of the right distributive law:

(m <!> n) >>- f = (m >>- f) <!> (m >>- f)
(m <!> n) >>= f = (m >>= f) <!> (m >>= f)

Minimal complete definition

(<!>)

Methods

(<!>) :: f a -> f a -> f a infixl 3 Source #

<|> without a required empty

some :: Applicative f => f a -> f [a] Source #

many :: Applicative f => f a -> f [a] Source #

Instances

 Alt [] Source # Methods() :: [a] -> [a] -> [a] Source #some :: Applicative [] => [a] -> [[a]] Source #many :: Applicative [] => [a] -> [[a]] Source # Source # Methods() :: Maybe a -> Maybe a -> Maybe a Source #some :: Applicative Maybe => Maybe a -> Maybe [a] Source #many :: Applicative Maybe => Maybe a -> Maybe [a] Source # Source # This instance does not actually satisfy the (<.>) right distributive law It instead satisfies the Left-Catch law Methods() :: IO a -> IO a -> IO a Source #some :: Applicative IO => IO a -> IO [a] Source #many :: Applicative IO => IO a -> IO [a] Source # Source # Methods() :: V1 a -> V1 a -> V1 a Source #some :: Applicative V1 => V1 a -> V1 [a] Source #many :: Applicative V1 => V1 a -> V1 [a] Source # Source # Methods() :: U1 a -> U1 a -> U1 a Source #some :: Applicative U1 => U1 a -> U1 [a] Source #many :: Applicative U1 => U1 a -> U1 [a] Source # Source # Methods() :: Option a -> Option a -> Option a Source #some :: Applicative Option => Option a -> Option [a] Source #many :: Applicative Option => Option a -> Option [a] Source # Source # Methods() :: NonEmpty a -> NonEmpty a -> NonEmpty a Source # Source # Methods() :: IntMap a -> IntMap a -> IntMap a Source #some :: Applicative IntMap => IntMap a -> IntMap [a] Source #many :: Applicative IntMap => IntMap a -> IntMap [a] Source # Source # Methods() :: Seq a -> Seq a -> Seq a Source #some :: Applicative Seq => Seq a -> Seq [a] Source #many :: Applicative Seq => Seq a -> Seq [a] Source # Alt (Either a) Source # Methods() :: Either a a -> Either a a -> Either a a Source #some :: Applicative (Either a) => Either a a -> Either a [a] Source #many :: Applicative (Either a) => Either a a -> Either a [a] Source # Alt f => Alt (Rec1 f) Source # Methods() :: Rec1 f a -> Rec1 f a -> Rec1 f a Source #some :: Applicative (Rec1 f) => Rec1 f a -> Rec1 f [a] Source #many :: Applicative (Rec1 f) => Rec1 f a -> Rec1 f [a] Source # MonadPlus m => Alt (WrappedMonad m) Source # Methods() :: WrappedMonad m a -> WrappedMonad m a -> WrappedMonad m a Source #some :: Applicative (WrappedMonad m) => WrappedMonad m a -> WrappedMonad m [a] Source #many :: Applicative (WrappedMonad m) => WrappedMonad m a -> WrappedMonad m [a] Source # Source # Methods() :: Proxy * a -> Proxy * a -> Proxy * a Source #some :: Applicative (Proxy *) => Proxy * a -> Proxy * [a] Source #many :: Applicative (Proxy *) => Proxy * a -> Proxy * [a] Source # Ord k => Alt (Map k) Source # Methods() :: Map k a -> Map k a -> Map k a Source #some :: Applicative (Map k) => Map k a -> Map k [a] Source #many :: Applicative (Map k) => Map k a -> Map k [a] Source # Alt f => Alt (Lift f) Source # Methods() :: Lift f a -> Lift f a -> Lift f a Source #some :: Applicative (Lift f) => Lift f a -> Lift f [a] Source #many :: Applicative (Lift f) => Lift f a -> Lift f [a] Source # (Bind f, Monad f) => Alt (MaybeT f) Source # Methods() :: MaybeT f a -> MaybeT f a -> MaybeT f a Source #some :: Applicative (MaybeT f) => MaybeT f a -> MaybeT f [a] Source #many :: Applicative (MaybeT f) => MaybeT f a -> MaybeT f [a] Source # Apply f => Alt (ListT f) Source # Methods() :: ListT f a -> ListT f a -> ListT f a Source #some :: Applicative (ListT f) => ListT f a -> ListT f [a] Source #many :: Applicative (ListT f) => ListT f a -> ListT f [a] Source # Source # Methods() :: WrappedApplicative f a -> WrappedApplicative f a -> WrappedApplicative f a Source #some :: Applicative (WrappedApplicative f) => WrappedApplicative f a -> WrappedApplicative f [a] Source #many :: Applicative (WrappedApplicative f) => WrappedApplicative f a -> WrappedApplicative f [a] Source # (Alt f, Alt g) => Alt ((:*:) f g) Source # Methods() :: (f :*: g) a -> (f :*: g) a -> (f :*: g) a Source #some :: Applicative (f :*: g) => (f :*: g) a -> (f :*: g) [a] Source #many :: Applicative (f :*: g) => (f :*: g) a -> (f :*: g) [a] Source # ArrowPlus a => Alt (WrappedArrow a b) Source # Methods() :: WrappedArrow a b a -> WrappedArrow a b a -> WrappedArrow a b a Source #some :: Applicative (WrappedArrow a b) => WrappedArrow a b a -> WrappedArrow a b [a] Source #many :: Applicative (WrappedArrow a b) => WrappedArrow a b a -> WrappedArrow a b [a] Source # Alt f => Alt (IdentityT * f) Source # Methods() :: IdentityT * f a -> IdentityT * f a -> IdentityT * f a Source #some :: Applicative (IdentityT * f) => IdentityT * f a -> IdentityT * f [a] Source #many :: Applicative (IdentityT * f) => IdentityT * f a -> IdentityT * f [a] Source # Alt f => Alt (Reverse * f) Source # Methods() :: Reverse * f a -> Reverse * f a -> Reverse * f a Source #some :: Applicative (Reverse * f) => Reverse * f a -> Reverse * f [a] Source #many :: Applicative (Reverse * f) => Reverse * f a -> Reverse * f [a] Source # Alt f => Alt (Backwards * f) Source # Methods() :: Backwards * f a -> Backwards * f a -> Backwards * f a Source #some :: Applicative (Backwards * f) => Backwards * f a -> Backwards * f [a] Source #many :: Applicative (Backwards * f) => Backwards * f a -> Backwards * f [a] Source # Alt f => Alt (WriterT w f) Source # Methods() :: WriterT w f a -> WriterT w f a -> WriterT w f a Source #some :: Applicative (WriterT w f) => WriterT w f a -> WriterT w f [a] Source #many :: Applicative (WriterT w f) => WriterT w f a -> WriterT w f [a] Source # Alt f => Alt (WriterT w f) Source # Methods() :: WriterT w f a -> WriterT w f a -> WriterT w f a Source #some :: Applicative (WriterT w f) => WriterT w f a -> WriterT w f [a] Source #many :: Applicative (WriterT w f) => WriterT w f a -> WriterT w f [a] Source # Alt f => Alt (StateT e f) Source # Methods() :: StateT e f a -> StateT e f a -> StateT e f a Source #some :: Applicative (StateT e f) => StateT e f a -> StateT e f [a] Source #many :: Applicative (StateT e f) => StateT e f a -> StateT e f [a] Source # Alt f => Alt (StateT e f) Source # Methods() :: StateT e f a -> StateT e f a -> StateT e f a Source #some :: Applicative (StateT e f) => StateT e f a -> StateT e f [a] Source #many :: Applicative (StateT e f) => StateT e f a -> StateT e f [a] Source # (Bind f, Monad f, Semigroup e) => Alt (ExceptT e f) Source # Methods() :: ExceptT e f a -> ExceptT e f a -> ExceptT e f a Source #some :: Applicative (ExceptT e f) => ExceptT e f a -> ExceptT e f [a] Source #many :: Applicative (ExceptT e f) => ExceptT e f a -> ExceptT e f [a] Source # (Bind f, Monad f) => Alt (ErrorT e f) Source # Methods() :: ErrorT e f a -> ErrorT e f a -> ErrorT e f a Source #some :: Applicative (ErrorT e f) => ErrorT e f a -> ErrorT e f [a] Source #many :: Applicative (ErrorT e f) => ErrorT e f a -> ErrorT e f [a] Source # Alt f => Alt (Static f a) Source # Methods() :: Static f a a -> Static f a a -> Static f a a Source #some :: Applicative (Static f a) => Static f a a -> Static f a [a] Source #many :: Applicative (Static f a) => Static f a a -> Static f a [a] Source # Alt f => Alt (M1 i c f) Source # Methods() :: M1 i c f a -> M1 i c f a -> M1 i c f a Source #some :: Applicative (M1 i c f) => M1 i c f a -> M1 i c f [a] Source #many :: Applicative (M1 i c f) => M1 i c f a -> M1 i c f [a] Source # (Alt f, Alt g) => Alt (Product * f g) Source # Methods() :: Product * f g a -> Product * f g a -> Product * f g a Source #some :: Applicative (Product * f g) => Product * f g a -> Product * f g [a] Source #many :: Applicative (Product * f g) => Product * f g a -> Product * f g [a] Source # Alt f => Alt (ReaderT * e f) Source # Methods() :: ReaderT * e f a -> ReaderT * e f a -> ReaderT * e f a Source #some :: Applicative (ReaderT * e f) => ReaderT * e f a -> ReaderT * e f [a] Source #many :: Applicative (ReaderT * e f) => ReaderT * e f a -> ReaderT * e f [a] Source # (Alt f, Functor g) => Alt (Compose * * f g) Source # Methods() :: Compose * * f g a -> Compose * * f g a -> Compose * * f g a Source #some :: Applicative (Compose * * f g) => Compose * * f g a -> Compose * * f g [a] Source #many :: Applicative (Compose * * f g) => Compose * * f g a -> Compose * * f g [a] Source # Alt f => Alt (RWST r w s f) Source # Methods() :: RWST r w s f a -> RWST r w s f a -> RWST r w s f a Source #some :: Applicative (RWST r w s f) => RWST r w s f a -> RWST r w s f [a] Source #many :: Applicative (RWST r w s f) => RWST r w s f a -> RWST r w s f [a] Source # Alt f => Alt (RWST r w s f) Source # Methods() :: RWST r w s f a -> RWST r w s f a -> RWST r w s f a Source #some :: Applicative (RWST r w s f) => RWST r w s f a -> RWST r w s f [a] Source #many :: Applicative (RWST r w s f) => RWST r w s f a -> RWST r w s f [a] Source #