base-4.20.0.0: Core data structures and operations

Control.Applicative

Description

This module describes a structure intermediate between a functor and a monad (technically, a strong lax monoidal functor). Compared with monads, this interface lacks the full power of the binding operation >>=, but

• it has more instances.
• it is sufficient for many uses, e.g. context-free parsing, or the Traversable class.
• instances can perform analysis of computations before they are executed, and thus produce shared optimizations.

This interface was introduced for parsers by Niklas Röjemo, because it admits more sharing than the monadic interface. The names here are mostly based on parsing work by Doaitse Swierstra.

For more details, see Applicative Programming with Effects, by Conor McBride and Ross Paterson.

Synopsis

# Applicative functors

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

A functor with application, providing operations to

• embed pure expressions (pure), and
• sequence computations and combine their results (<*> and liftA2).

A minimal complete definition must include implementations of pure and of either <*> or liftA2. If it defines both, then they must behave the same as their default definitions:

(<*>) = liftA2 id
liftA2 f x y = f <$> x <*> y Further, any definition must satisfy the following: Identity pure id <*> v = v Composition pure (.) <*> u <*> v <*> w = u <*> (v <*> w) Homomorphism pure f <*> pure x = pure (f x) Interchange u <*> pure y = pure ($ y) <*> u

The other methods have the following default definitions, which may be overridden with equivalent specialized implementations:

• u *> v = (id <$ u) <*> v • u <* v = liftA2 const u v As a consequence of these laws, the Functor instance for f will satisfy • fmap f x = pure f <*> x It may be useful to note that supposing forall x y. p (q x y) = f x . g y it follows from the above that liftA2 p (liftA2 q u v) = liftA2 f u . liftA2 g v If f is also a Monad, it should satisfy • pure = return • m1 <*> m2 = m1 >>= (\x1 -> m2 >>= (\x2 -> return (x1 x2))) • (*>) = (>>) (which implies that pure and <*> satisfy the applicative functor laws). Minimal complete definition pure, ((<*>) | liftA2) Methods pure :: a -> f a Source # Lift a value into the Structure. #### Examples Expand >>> pure 1 :: Maybe Int Just 1  >>> pure 'z' :: [Char] "z"  >>> pure (pure ":D") :: Maybe [String] Just [":D"]  (<*>) :: f (a -> b) -> f a -> f b infixl 4 Source # Sequential application. A few functors support an implementation of <*> that is more efficient than the default one. #### Example Expand Used in combination with (<$>), (<*>) can be used to build a record.

>>> data MyState = MyState {arg1 :: Foo, arg2 :: Bar, arg3 :: Baz}

>>> produceFoo :: Applicative f => f Foo
>>> produceBar :: Applicative f => f Bar
>>> produceBaz :: Applicative f => f Baz

>>> mkState :: Applicative f => f MyState
>>> mkState = MyState <$> produceFoo <*> produceBar <*> produceBaz  liftA2 :: (a -> b -> c) -> f a -> f b -> f c Source # Lift a binary function to actions. Some functors support an implementation of liftA2 that is more efficient than the default one. In particular, if fmap is an expensive operation, it is likely better to use liftA2 than to fmap over the structure and then use <*>. This became a typeclass method in 4.10.0.0. Prior to that, it was a function defined in terms of <*> and fmap. #### Example Expand >>> liftA2 (,) (Just 3) (Just 5) Just (3,5)  >>> liftA2 (+) [1, 2, 3] [4, 5, 6] [5,6,7,6,7,8,7,8,9]  (*>) :: f a -> f b -> f b infixl 4 Source # Sequence actions, discarding the value of the first argument. #### Examples Expand If used in conjunction with the Applicative instance for Maybe, you can chain Maybe computations, with a possible "early return" in case of Nothing. >>> Just 2 *> Just 3 Just 3  >>> Nothing *> Just 3 Nothing  Of course a more interesting use case would be to have effectful computations instead of just returning pure values. >>> import Data.Char >>> import GHC.Internal.Text.ParserCombinators.ReadP >>> let p = string "my name is " *> munch1 isAlpha <* eof >>> readP_to_S p "my name is Simon" [("Simon","")]  (<*) :: f a -> f b -> f a infixl 4 Source # Sequence actions, discarding the value of the second argument. #### Instances Instances details  Source # Since: base-4.9.0.0 Instance detailsDefined in Data.Complex Methodspure :: a -> Complex a Source #(<*>) :: Complex (a -> b) -> Complex a -> Complex b Source #liftA2 :: (a -> b -> c) -> Complex a -> Complex b -> Complex c Source #(*>) :: Complex a -> Complex b -> Complex b Source #(<*) :: Complex a -> Complex b -> Complex a Source # Source # Since: base-4.9.0.0 Instance detailsDefined in Data.Semigroup Methodspure :: a -> First a Source #(<*>) :: First (a -> b) -> First a -> First b Source #liftA2 :: (a -> b -> c) -> First a -> First b -> First c Source #(*>) :: First a -> First b -> First b Source #(<*) :: First a -> First b -> First a Source # Source # Since: base-4.9.0.0 Instance detailsDefined in Data.Semigroup Methodspure :: a -> Last a Source #(<*>) :: Last (a -> b) -> Last a -> Last b Source #liftA2 :: (a -> b -> c) -> Last a -> Last b -> Last c Source #(*>) :: Last a -> Last b -> Last b Source #(<*) :: Last a -> Last b -> Last a Source # Source # Since: base-4.9.0.0 Instance detailsDefined in Data.Semigroup Methodspure :: a -> Max a Source #(<*>) :: Max (a -> b) -> Max a -> Max b Source #liftA2 :: (a -> b -> c) -> Max a -> Max b -> Max c Source #(*>) :: Max a -> Max b -> Max b Source #(<*) :: Max a -> Max b -> Max a Source # Source # Since: base-4.9.0.0 Instance detailsDefined in Data.Semigroup Methodspure :: a -> Min a Source #(<*>) :: Min (a -> b) -> Min a -> Min b Source #liftA2 :: (a -> b -> c) -> Min a -> Min b -> Min c Source #(*>) :: Min a -> Min b -> Min b Source #(<*) :: Min a -> Min b -> Min a Source # @since base-4.9.0.0 Instance detailsDefined in GHC.Internal.Base Methodspure :: a -> NonEmpty a Source #(<*>) :: NonEmpty (a -> b) -> NonEmpty a -> NonEmpty b Source #liftA2 :: (a -> b -> c) -> NonEmpty a -> NonEmpty b -> NonEmpty c Source #(*>) :: NonEmpty a -> NonEmpty b -> NonEmpty b Source #(<*) :: NonEmpty a -> NonEmpty b -> NonEmpty a Source # @since base-4.8.0.0 Instance detailsDefined in GHC.Internal.Conc.Sync Methodspure :: a -> STM a Source #(<*>) :: STM (a -> b) -> STM a -> STM b Source #liftA2 :: (a -> b -> c) -> STM a -> STM b -> STM c Source #(*>) :: STM a -> STM b -> STM b Source #(<*) :: STM a -> STM b -> STM a Source # @since base-4.8.0.0 Instance detailsDefined in GHC.Internal.Data.Functor.Identity Methodspure :: a -> Identity a Source #(<*>) :: Identity (a -> b) -> Identity a -> Identity b Source #liftA2 :: (a -> b -> c) -> Identity a -> Identity b -> Identity c Source #(*>) :: Identity a -> Identity b -> Identity b Source #(<*) :: Identity a -> Identity b -> Identity a Source # @since base-4.8.0.0 Instance detailsDefined in GHC.Internal.Data.Monoid Methodspure :: a -> First a Source #(<*>) :: First (a -> b) -> First a -> First b Source #liftA2 :: (a -> b -> c) -> First a -> First b -> First c Source #(*>) :: First a -> First b -> First b Source #(<*) :: First a -> First b -> First a Source # @since base-4.8.0.0 Instance detailsDefined in GHC.Internal.Data.Monoid Methodspure :: a -> Last a Source #(<*>) :: Last (a -> b) -> Last a -> Last b Source #liftA2 :: (a -> b -> c) -> Last a -> Last b -> Last c Source #(*>) :: Last a -> Last b -> Last b Source #(<*) :: Last a -> Last b -> Last a Source # @since base-4.11.0.0 Instance detailsDefined in GHC.Internal.Data.Ord Methodspure :: a -> Down a Source #(<*>) :: Down (a -> b) -> Down a -> Down b Source #liftA2 :: (a -> b -> c) -> Down a -> Down b -> Down c Source #(*>) :: Down a -> Down b -> Down b Source #(<*) :: Down a -> Down b -> Down a Source # @since base-4.8.0.0 Instance detailsDefined in GHC.Internal.Data.Semigroup.Internal Methodspure :: a -> Dual a Source #(<*>) :: Dual (a -> b) -> Dual a -> Dual b Source #liftA2 :: (a -> b -> c) -> Dual a -> Dual b -> Dual c Source #(*>) :: Dual a -> Dual b -> Dual b Source #(<*) :: Dual a -> Dual b -> Dual a Source # @since base-4.8.0.0 Instance detailsDefined in GHC.Internal.Data.Semigroup.Internal Methodspure :: a -> Product a Source #(<*>) :: Product (a -> b) -> Product a -> Product b Source #liftA2 :: (a -> b -> c) -> Product a -> Product b -> Product c Source #(*>) :: Product a -> Product b -> Product b Source #(<*) :: Product a -> Product b -> Product a Source # @since base-4.8.0.0 Instance detailsDefined in GHC.Internal.Data.Semigroup.Internal Methodspure :: a -> Sum a Source #(<*>) :: Sum (a -> b) -> Sum a -> Sum b Source #liftA2 :: (a -> b -> c) -> Sum a -> Sum b -> Sum c Source #(*>) :: Sum a -> Sum b -> Sum b Source #(<*) :: Sum a -> Sum b -> Sum a Source # f <$> ZipList xs1 <*> ... <*> ZipList xsN = ZipList (zipWithN f xs1 ... xsN)where zipWithN refers to the zipWith function of the appropriate arity (zipWith, zipWith3, zipWith4, ...). For example:(\a b c -> stimes c [a, b]) <$> ZipList "abcd" <*> ZipList "567" <*> ZipList [1..] = ZipList (zipWith3 (\a b c -> stimes c [a, b]) "abcd" "567" [1..]) = ZipList {getZipList = ["a5","b6b6","c7c7c7"]}@since base-2.01 Instance detailsDefined in GHC.Internal.Functor.ZipList Methodspure :: a -> ZipList a Source #(<*>) :: ZipList (a -> b) -> ZipList a -> ZipList b Source #liftA2 :: (a -> b -> c) -> ZipList a -> ZipList b -> ZipList c Source #(*>) :: ZipList a -> ZipList b -> ZipList b Source #(<*) :: ZipList a -> ZipList b -> ZipList a Source # @since base-4.8.0.0 Instance detailsDefined in GHC.Internal.GHCi Methodspure :: a -> NoIO a Source #(<*>) :: NoIO (a -> b) -> NoIO a -> NoIO b Source #liftA2 :: (a -> b -> c) -> NoIO a -> NoIO b -> NoIO c Source #(*>) :: NoIO a -> NoIO b -> NoIO b Source #(<*) :: NoIO a -> NoIO b -> NoIO a Source # @since base-4.9.0.0 Instance detailsDefined in GHC.Internal.Generics Methodspure :: a -> Par1 a Source #(<*>) :: Par1 (a -> b) -> Par1 a -> Par1 b Source #liftA2 :: (a -> b -> c) -> Par1 a -> Par1 b -> Par1 c Source #(*>) :: Par1 a -> Par1 b -> Par1 b Source #(<*) :: Par1 a -> Par1 b -> Par1 a Source # @since base-4.5.0.0 Instance details Methodspure :: a -> P a Source #(<*>) :: P (a -> b) -> P a -> P b Source #liftA2 :: (a -> b -> c) -> P a -> P b -> P c Source #(*>) :: P a -> P b -> P b Source #(<*) :: P a -> P b -> P a Source # @since base-4.6.0.0 Instance details Methodspure :: a -> ReadP a Source #(<*>) :: ReadP (a -> b) -> ReadP a -> ReadP b Source #liftA2 :: (a -> b -> c) -> ReadP a -> ReadP b -> ReadP c Source #(*>) :: ReadP a -> ReadP b -> ReadP b Source #(<*) :: ReadP a -> ReadP b -> ReadP a Source # @since base-4.6.0.0 Instance details Methodspure :: a -> ReadPrec a Source #(<*>) :: ReadPrec (a -> b) -> ReadPrec a -> ReadPrec b Source #liftA2 :: (a -> b -> c) -> ReadPrec a -> ReadPrec b -> ReadPrec c Source #(*>) :: ReadPrec a -> ReadPrec b -> ReadPrec b Source #(<*) :: ReadPrec a -> ReadPrec b -> ReadPrec a Source # @since base-2.01 Instance detailsDefined in GHC.Internal.Base Methodspure :: a -> IO a Source #(<*>) :: IO (a -> b) -> IO a -> IO b Source #liftA2 :: (a -> b -> c) -> IO a -> IO b -> IO c Source #(*>) :: IO a -> IO b -> IO b Source #(<*) :: IO a -> IO b -> IO a Source # @since base-2.01 Instance detailsDefined in GHC.Internal.Base Methodspure :: a -> Maybe a Source #(<*>) :: Maybe (a -> b) -> Maybe a -> Maybe b Source #liftA2 :: (a -> b -> c) -> Maybe a -> Maybe b -> Maybe c Source #(*>) :: Maybe a -> Maybe b -> Maybe b Source #(<*) :: Maybe a -> Maybe b -> Maybe a Source # @since base-4.15 Instance detailsDefined in GHC.Internal.Base Methodspure :: a -> Solo a Source #(<*>) :: Solo (a -> b) -> Solo a -> Solo b Source #liftA2 :: (a -> b -> c) -> Solo a -> Solo b -> Solo c Source #(*>) :: Solo a -> Solo b -> Solo b Source #(<*) :: Solo a -> Solo b -> Solo a Source # @since base-2.01 Instance detailsDefined in GHC.Internal.Base Methodspure :: a -> [a] Source #(<*>) :: [a -> b] -> [a] -> [b] Source #liftA2 :: (a -> b -> c) -> [a] -> [b] -> [c] Source #(*>) :: [a] -> [b] -> [b] Source #(<*) :: [a] -> [b] -> [a] Source # Monad m => Applicative (WrappedMonad m) Source # Since: base-2.1 Instance detailsDefined in Control.Applicative Methodspure :: a -> WrappedMonad m a Source #(<*>) :: WrappedMonad m (a -> b) -> WrappedMonad m a -> WrappedMonad m b Source #liftA2 :: (a -> b -> c) -> WrappedMonad m a -> WrappedMonad m b -> WrappedMonad m c Source #(*>) :: WrappedMonad m a -> WrappedMonad m b -> WrappedMonad m b Source #(<*) :: WrappedMonad m a -> WrappedMonad m b -> WrappedMonad m a Source # Arrow a => Applicative (ArrowMonad a) @since base-4.6.0.0 Instance detailsDefined in GHC.Internal.Control.Arrow Methodspure :: a0 -> ArrowMonad a a0 Source #(<*>) :: ArrowMonad a (a0 -> b) -> ArrowMonad a a0 -> ArrowMonad a b Source #liftA2 :: (a0 -> b -> c) -> ArrowMonad a a0 -> ArrowMonad a b -> ArrowMonad a c Source #(*>) :: ArrowMonad a a0 -> ArrowMonad a b -> ArrowMonad a b Source #(<*) :: ArrowMonad a a0 -> ArrowMonad a b -> ArrowMonad a a0 Source # @since base-2.01 Instance detailsDefined in GHC.Internal.Control.Monad.ST.Lazy.Imp Methodspure :: a -> ST s a Source #(<*>) :: ST s (a -> b) -> ST s a -> ST s b Source #liftA2 :: (a -> b -> c) -> ST s a -> ST s b -> ST s c Source #(*>) :: ST s a -> ST s b -> ST s b Source #(<*) :: ST s a -> ST s b -> ST s a Source # @since base-3.0 Instance detailsDefined in GHC.Internal.Data.Either Methodspure :: a -> Either e a Source #(<*>) :: Either e (a -> b) -> Either e a -> Either e b Source #liftA2 :: (a -> b -> c) -> Either e a -> Either e b -> Either e c Source #(*>) :: Either e a -> Either e b -> Either e b Source #(<*) :: Either e a -> Either e b -> Either e a Source # @since base-4.0 Instance detailsDefined in GHC.Internal.Data.Functor.Utils Methodspure :: a -> StateL s a Source #(<*>) :: StateL s (a -> b) -> StateL s a -> StateL s b Source #liftA2 :: (a -> b -> c) -> StateL s a -> StateL s b -> StateL s c Source #(*>) :: StateL s a -> StateL s b -> StateL s b Source #(<*) :: StateL s a -> StateL s b -> StateL s a Source # @since base-4.0 Instance detailsDefined in GHC.Internal.Data.Functor.Utils Methodspure :: a -> StateR s a Source #(<*>) :: StateR s (a -> b) -> StateR s a -> StateR s b Source #liftA2 :: (a -> b -> c) -> StateR s a -> StateR s b -> StateR s c Source #(*>) :: StateR s a -> StateR s b -> StateR s b Source #(<*) :: StateR s a -> StateR s b -> StateR s a Source # Applicative (Proxy :: Type -> Type) @since base-4.7.0.0 Instance detailsDefined in GHC.Internal.Data.Proxy Methodspure :: a -> Proxy a Source #(<*>) :: Proxy (a -> b) -> Proxy a -> Proxy b Source #liftA2 :: (a -> b -> c) -> Proxy a -> Proxy b -> Proxy c Source #(*>) :: Proxy a -> Proxy b -> Proxy b Source #(<*) :: Proxy a -> Proxy b -> Proxy a Source # Applicative (U1 :: Type -> Type) @since base-4.9.0.0 Instance detailsDefined in GHC.Internal.Generics Methodspure :: a -> U1 a Source #(<*>) :: U1 (a -> b) -> U1 a -> U1 b Source #liftA2 :: (a -> b -> c) -> U1 a -> U1 b -> U1 c Source #(*>) :: U1 a -> U1 b -> U1 b Source #(<*) :: U1 a -> U1 b -> U1 a Source # @since base-4.4.0.0 Instance detailsDefined in GHC.Internal.ST Methodspure :: a -> ST s a Source #(<*>) :: ST s (a -> b) -> ST s a -> ST s b Source #liftA2 :: (a -> b -> c) -> ST s a -> ST s b -> ST s c Source #(*>) :: ST s a -> ST s b -> ST s b Source #(<*) :: ST s a -> ST s b -> ST s a Source # Monoid a => Applicative ((,) a) For tuples, the Monoid constraint on a determines how the first values merge. For example, Strings concatenate:("hello ", (+15)) <*> ("world!", 2002) ("hello world!",2017)@since base-2.01 Instance detailsDefined in GHC.Internal.Base Methodspure :: a0 -> (a, a0) Source #(<*>) :: (a, a0 -> b) -> (a, a0) -> (a, b) Source #liftA2 :: (a0 -> b -> c) -> (a, a0) -> (a, b) -> (a, c) Source #(*>) :: (a, a0) -> (a, b) -> (a, b) Source #(<*) :: (a, a0) -> (a, b) -> (a, a0) Source # Arrow a => Applicative (WrappedArrow a b) Source # Since: base-2.1 Instance detailsDefined in Control.Applicative Methodspure :: a0 -> WrappedArrow a b a0 Source #(<*>) :: WrappedArrow a b (a0 -> b0) -> WrappedArrow a b a0 -> WrappedArrow a b b0 Source #liftA2 :: (a0 -> b0 -> c) -> WrappedArrow a b a0 -> WrappedArrow a b b0 -> WrappedArrow a b c Source #(*>) :: WrappedArrow a b a0 -> WrappedArrow a b b0 -> WrappedArrow a b b0 Source #(<*) :: WrappedArrow a b a0 -> WrappedArrow a b b0 -> WrappedArrow a b a0 Source # Applicative m => Applicative (Kleisli m a) @since base-4.14.0.0 Instance detailsDefined in GHC.Internal.Control.Arrow Methodspure :: a0 -> Kleisli m a a0 Source #(<*>) :: Kleisli m a (a0 -> b) -> Kleisli m a a0 -> Kleisli m a b Source #liftA2 :: (a0 -> b -> c) -> Kleisli m a a0 -> Kleisli m a b -> Kleisli m a c Source #(*>) :: Kleisli m a a0 -> Kleisli m a b -> Kleisli m a b Source #(<*) :: Kleisli m a a0 -> Kleisli m a b -> Kleisli m a a0 Source # Monoid m => Applicative (Const m :: Type -> Type) @since base-2.0.1 Instance detailsDefined in GHC.Internal.Data.Functor.Const Methodspure :: a -> Const m a Source #(<*>) :: Const m (a -> b) -> Const m a -> Const m b Source #liftA2 :: (a -> b -> c) -> Const m a -> Const m b -> Const m c Source #(*>) :: Const m a -> Const m b -> Const m b Source #(<*) :: Const m a -> Const m b -> Const m a Source # Monad m => Applicative (StateT s m) @since base-4.18.0.0 Instance detailsDefined in GHC.Internal.Data.Functor.Utils Methodspure :: a -> StateT s m a Source #(<*>) :: StateT s m (a -> b) -> StateT s m a -> StateT s m b Source #liftA2 :: (a -> b -> c) -> StateT s m a -> StateT s m b -> StateT s m c Source #(*>) :: StateT s m a -> StateT s m b -> StateT s m b Source #(<*) :: StateT s m a -> StateT s m b -> StateT s m a Source # Applicative f => Applicative (Ap f) @since base-4.12.0.0 Instance detailsDefined in GHC.Internal.Data.Monoid Methodspure :: a -> Ap f a Source #(<*>) :: Ap f (a -> b) -> Ap f a -> Ap f b Source #liftA2 :: (a -> b -> c) -> Ap f a -> Ap f b -> Ap f c Source #(*>) :: Ap f a -> Ap f b -> Ap f b Source #(<*) :: Ap f a -> Ap f b -> Ap f a Source # Applicative f => Applicative (Alt f) @since base-4.8.0.0 Instance detailsDefined in GHC.Internal.Data.Semigroup.Internal Methodspure :: a -> Alt f a Source #(<*>) :: Alt f (a -> b) -> Alt f a -> Alt f b Source #liftA2 :: (a -> b -> c) -> Alt f a -> Alt f b -> Alt f c Source #(*>) :: Alt f a -> Alt f b -> Alt f b Source #(<*) :: Alt f a -> Alt f b -> Alt f a Source # (Generic1 f, Applicative (Rep1 f)) => Applicative (Generically1 f) @since base-4.17.0.0 Instance detailsDefined in GHC.Internal.Generics Methodspure :: a -> Generically1 f a Source #(<*>) :: Generically1 f (a -> b) -> Generically1 f a -> Generically1 f b Source #liftA2 :: (a -> b -> c) -> Generically1 f a -> Generically1 f b -> Generically1 f c Source #(*>) :: Generically1 f a -> Generically1 f b -> Generically1 f b Source #(<*) :: Generically1 f a -> Generically1 f b -> Generically1 f a Source # Applicative f => Applicative (Rec1 f) @since base-4.9.0.0 Instance detailsDefined in GHC.Internal.Generics Methodspure :: a -> Rec1 f a Source #(<*>) :: Rec1 f (a -> b) -> Rec1 f a -> Rec1 f b Source #liftA2 :: (a -> b -> c) -> Rec1 f a -> Rec1 f b -> Rec1 f c Source #(*>) :: Rec1 f a -> Rec1 f b -> Rec1 f b Source #(<*) :: Rec1 f a -> Rec1 f b -> Rec1 f a Source # (Monoid a, Monoid b) => Applicative ((,,) a b) @since base-4.14.0.0 Instance detailsDefined in GHC.Internal.Base Methodspure :: a0 -> (a, b, a0) Source #(<*>) :: (a, b, a0 -> b0) -> (a, b, a0) -> (a, b, b0) Source #liftA2 :: (a0 -> b0 -> c) -> (a, b, a0) -> (a, b, b0) -> (a, b, c) Source #(*>) :: (a, b, a0) -> (a, b, b0) -> (a, b, b0) Source #(<*) :: (a, b, a0) -> (a, b, b0) -> (a, b, a0) Source # (Applicative f, Applicative g) => Applicative (Product f g) Source # Since: base-4.9.0.0 Instance detailsDefined in Data.Functor.Product Methodspure :: a -> Product f g a Source #(<*>) :: Product f g (a -> b) -> Product f g a -> Product f g b Source #liftA2 :: (a -> b -> c) -> Product f g a -> Product f g b -> Product f g c Source #(*>) :: Product f g a -> Product f g b -> Product f g b Source #(<*) :: Product f g a -> Product f g b -> Product f g a Source # (Applicative f, Applicative g) => Applicative (f :*: g) @since base-4.9.0.0 Instance detailsDefined in GHC.Internal.Generics Methodspure :: a -> (f :*: g) a Source #(<*>) :: (f :*: g) (a -> b) -> (f :*: g) a -> (f :*: g) b Source #liftA2 :: (a -> b -> c) -> (f :*: g) a -> (f :*: g) b -> (f :*: g) c Source #(*>) :: (f :*: g) a -> (f :*: g) b -> (f :*: g) b Source #(<*) :: (f :*: g) a -> (f :*: g) b -> (f :*: g) a Source # Monoid c => Applicative (K1 i c :: Type -> Type) @since base-4.12.0.0 Instance detailsDefined in GHC.Internal.Generics Methodspure :: a -> K1 i c a Source #(<*>) :: K1 i c (a -> b) -> K1 i c a -> K1 i c b Source #liftA2 :: (a -> b -> c0) -> K1 i c a -> K1 i c b -> K1 i c c0 Source #(*>) :: K1 i c a -> K1 i c b -> K1 i c b Source #(<*) :: K1 i c a -> K1 i c b -> K1 i c a Source # (Monoid a, Monoid b, Monoid c) => Applicative ((,,,) a b c) @since base-4.14.0.0 Instance detailsDefined in GHC.Internal.Base Methodspure :: a0 -> (a, b, c, a0) Source #(<*>) :: (a, b, c, a0 -> b0) -> (a, b, c, a0) -> (a, b, c, b0) Source #liftA2 :: (a0 -> b0 -> c0) -> (a, b, c, a0) -> (a, b, c, b0) -> (a, b, c, c0) Source #(*>) :: (a, b, c, a0) -> (a, b, c, b0) -> (a, b, c, b0) Source #(<*) :: (a, b, c, a0) -> (a, b, c, b0) -> (a, b, c, a0) Source # Applicative ((->) r) @since base-2.01 Instance detailsDefined in GHC.Internal.Base Methodspure :: a -> r -> a Source #(<*>) :: (r -> (a -> b)) -> (r -> a) -> r -> b Source #liftA2 :: (a -> b -> c) -> (r -> a) -> (r -> b) -> r -> c Source #(*>) :: (r -> a) -> (r -> b) -> r -> b Source #(<*) :: (r -> a) -> (r -> b) -> r -> a Source # (Applicative f, Applicative g) => Applicative (Compose f g) Source # Since: base-4.9.0.0 Instance detailsDefined in Data.Functor.Compose Methodspure :: a -> Compose f g a Source #(<*>) :: Compose f g (a -> b) -> Compose f g a -> Compose f g b Source #liftA2 :: (a -> b -> c) -> Compose f g a -> Compose f g b -> Compose f g c Source #(*>) :: Compose f g a -> Compose f g b -> Compose f g b Source #(<*) :: Compose f g a -> Compose f g b -> Compose f g a Source # (Applicative f, Applicative g) => Applicative (f :.: g) @since base-4.9.0.0 Instance detailsDefined in GHC.Internal.Generics Methodspure :: a -> (f :.: g) a Source #(<*>) :: (f :.: g) (a -> b) -> (f :.: g) a -> (f :.: g) b Source #liftA2 :: (a -> b -> c) -> (f :.: g) a -> (f :.: g) b -> (f :.: g) c Source #(*>) :: (f :.: g) a -> (f :.: g) b -> (f :.: g) b Source #(<*) :: (f :.: g) a -> (f :.: g) b -> (f :.: g) a Source # Applicative f => Applicative (M1 i c f) @since base-4.9.0.0 Instance detailsDefined in GHC.Internal.Generics Methodspure :: a -> M1 i c f a Source #(<*>) :: M1 i c f (a -> b) -> M1 i c f a -> M1 i c f b Source #liftA2 :: (a -> b -> c0) -> M1 i c f a -> M1 i c f b -> M1 i c f c0 Source #(*>) :: M1 i c f a -> M1 i c f b -> M1 i c f b Source #(<*) :: M1 i c f a -> M1 i c f b -> M1 i c f a Source # # Alternatives class Applicative f => Alternative (f :: Type -> Type) where Source # 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 []

#### Examples

Expand
>>> Nothing <|> Just 42
Just 42

>>> [1, 2] <|> [3, 4]
[1,2,3,4]

>>> empty <|> print (2^15)
32768


Minimal complete definition

Methods

empty :: f a Source #

The identity of <|>

empty <|> a     == a
a     <|> empty == a

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

An associative binary operation

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

One or more.

#### Examples

Expand
>>> some (putStr "la")
lalalalalalalalala... * goes on forever *

>>> some Nothing
nothing

>>> take 5 <$> some (Just 1) * hangs forever *  Note that this function can be used with Parsers based on Applicatives. In that case some parser will attempt to parse parser one or more times until it fails. many :: f a -> f [a] Source # Zero or more. #### Examples Expand >>> many (putStr "la") lalalalalalalalala... * goes on forever *  >>> many Nothing Just []  >>> take 5 <$> many (Just 1)
* hangs forever *


Note that this function can be used with Parsers based on Applicatives. In that case many parser will attempt to parse parser zero or more times until it fails.

#### Instances

Instances details
 Takes the first non-retrying STM action.@since base-4.8.0.0 Instance detailsDefined in GHC.Internal.Conc.Sync Methods(<|>) :: STM a -> STM a -> STM a Source #some :: STM a -> STM [a] Source #many :: STM a -> STM [a] Source # @since base-4.11.0.0 Instance detailsDefined in GHC.Internal.Functor.ZipList Methods(<|>) :: ZipList a -> ZipList a -> ZipList a Source #some :: ZipList a -> ZipList [a] Source #many :: ZipList a -> ZipList [a] Source # @since base-4.5.0.0 Instance details Methodsempty :: P a Source #(<|>) :: P a -> P a -> P a Source #some :: P a -> P [a] Source #many :: P a -> P [a] Source # @since base-4.6.0.0 Instance details Methods(<|>) :: ReadP a -> ReadP a -> ReadP a Source #some :: ReadP a -> ReadP [a] Source #many :: ReadP a -> ReadP [a] Source # @since base-4.6.0.0 Instance details Methods(<|>) :: ReadPrec a -> ReadPrec a -> ReadPrec a Source #some :: ReadPrec a -> ReadPrec [a] Source #many :: ReadPrec a -> ReadPrec [a] Source # Takes the first non-throwing IO action's result. empty throws an exception.@since base-4.9.0.0 Instance detailsDefined in GHC.Internal.Base Methods(<|>) :: IO a -> IO a -> IO a Source #some :: IO a -> IO [a] Source #many :: IO a -> IO [a] Source # Picks the leftmost Just value, or, alternatively, Nothing.@since base-2.01 Instance detailsDefined in GHC.Internal.Base Methods(<|>) :: Maybe a -> Maybe a -> Maybe a Source #some :: Maybe a -> Maybe [a] Source #many :: Maybe a -> Maybe [a] Source # Combines lists by concatenation, starting from the empty list.@since base-2.01 Instance detailsDefined in GHC.Internal.Base Methodsempty :: [a] Source #(<|>) :: [a] -> [a] -> [a] Source #some :: [a] -> [[a]] Source #many :: [a] -> [[a]] Source # Source # Since: base-2.1 Instance detailsDefined in Control.Applicative Methods(<|>) :: WrappedMonad m a -> WrappedMonad m a -> WrappedMonad m a Source #some :: WrappedMonad m a -> WrappedMonad m [a] Source #many :: WrappedMonad m a -> WrappedMonad m [a] Source # @since base-4.6.0.0 Instance detailsDefined in GHC.Internal.Control.Arrow Methodsempty :: ArrowMonad a a0 Source #(<|>) :: ArrowMonad a a0 -> ArrowMonad a a0 -> ArrowMonad a a0 Source #some :: ArrowMonad a a0 -> ArrowMonad a [a0] Source #many :: ArrowMonad a a0 -> ArrowMonad a [a0] Source # Alternative (Proxy :: Type -> Type) @since base-4.9.0.0 Instance detailsDefined in GHC.Internal.Data.Proxy Methods(<|>) :: Proxy a -> Proxy a -> Proxy a Source #some :: Proxy a -> Proxy [a] Source #many :: Proxy a -> Proxy [a] Source # Alternative (U1 :: Type -> Type) @since base-4.9.0.0 Instance detailsDefined in GHC.Internal.Generics Methods(<|>) :: U1 a -> U1 a -> U1 a Source #some :: U1 a -> U1 [a] Source #many :: U1 a -> U1 [a] Source # (ArrowZero a, ArrowPlus a) => Alternative (WrappedArrow a b) Source # Since: base-2.1 Instance detailsDefined in Control.Applicative Methodsempty :: WrappedArrow a b a0 Source #(<|>) :: WrappedArrow a b a0 -> WrappedArrow a b a0 -> WrappedArrow a b a0 Source #some :: WrappedArrow a b a0 -> WrappedArrow a b [a0] Source #many :: WrappedArrow a b a0 -> WrappedArrow a b [a0] Source # Alternative m => Alternative (Kleisli m a) @since base-4.14.0.0 Instance detailsDefined in GHC.Internal.Control.Arrow Methodsempty :: Kleisli m a a0 Source #(<|>) :: Kleisli m a a0 -> Kleisli m a a0 -> Kleisli m a a0 Source #some :: Kleisli m a a0 -> Kleisli m a [a0] Source #many :: Kleisli m a a0 -> Kleisli m a [a0] Source # Alternative f => Alternative (Ap f) @since base-4.12.0.0 Instance detailsDefined in GHC.Internal.Data.Monoid Methodsempty :: Ap f a Source #(<|>) :: Ap f a -> Ap f a -> Ap f a Source #some :: Ap f a -> Ap f [a] Source #many :: Ap f a -> Ap f [a] Source # Alternative f => Alternative (Alt f) @since base-4.8.0.0 Instance detailsDefined in GHC.Internal.Data.Semigroup.Internal Methodsempty :: Alt f a Source #(<|>) :: Alt f a -> Alt f a -> Alt f a Source #some :: Alt f a -> Alt f [a] Source #many :: Alt f a -> Alt f [a] Source # (Generic1 f, Alternative (Rep1 f)) => Alternative (Generically1 f) @since base-4.17.0.0 Instance detailsDefined in GHC.Internal.Generics Methods(<|>) :: Generically1 f a -> Generically1 f a -> Generically1 f a Source #some :: Generically1 f a -> Generically1 f [a] Source #many :: Generically1 f a -> Generically1 f [a] Source # Alternative f => Alternative (Rec1 f) @since base-4.9.0.0 Instance detailsDefined in GHC.Internal.Generics Methodsempty :: Rec1 f a Source #(<|>) :: Rec1 f a -> Rec1 f a -> Rec1 f a Source #some :: Rec1 f a -> Rec1 f [a] Source #many :: Rec1 f a -> Rec1 f [a] Source # (Alternative f, Alternative g) => Alternative (Product f g) Source # Since: base-4.9.0.0 Instance detailsDefined in Data.Functor.Product Methodsempty :: Product f g a Source #(<|>) :: Product f g a -> Product f g a -> Product f g a Source #some :: Product f g a -> Product f g [a] Source #many :: Product f g a -> Product f g [a] Source # (Alternative f, Alternative g) => Alternative (f :*: g) @since base-4.9.0.0 Instance detailsDefined in GHC.Internal.Generics Methodsempty :: (f :*: g) a Source #(<|>) :: (f :*: g) a -> (f :*: g) a -> (f :*: g) a Source #some :: (f :*: g) a -> (f :*: g) [a] Source #many :: (f :*: g) a -> (f :*: g) [a] Source # (Alternative f, Applicative g) => Alternative (Compose f g) Source # Since: base-4.9.0.0 Instance detailsDefined in Data.Functor.Compose Methodsempty :: Compose f g a Source #(<|>) :: Compose f g a -> Compose f g a -> Compose f g a Source #some :: Compose f g a -> Compose f g [a] Source #many :: Compose f g a -> Compose f g [a] Source # (Alternative f, Applicative g) => Alternative (f :.: g) @since base-4.9.0.0 Instance detailsDefined in GHC.Internal.Generics Methodsempty :: (f :.: g) a Source #(<|>) :: (f :.: g) a -> (f :.: g) a -> (f :.: g) a Source #some :: (f :.: g) a -> (f :.: g) [a] Source #many :: (f :.: g) a -> (f :.: g) [a] Source # Alternative f => Alternative (M1 i c f) @since base-4.9.0.0 Instance detailsDefined in GHC.Internal.Generics Methodsempty :: M1 i c f a Source #(<|>) :: M1 i c f a -> M1 i c f a -> M1 i c f a Source #some :: M1 i c f a -> M1 i c f [a] Source #many :: M1 i c f a -> M1 i c f [a] Source #

# Instances

newtype Const a (b :: k) Source #

The Const functor.

#### Examples

Expand
>>> fmap (++ "World") (Const "Hello")
Const "Hello"


Because we ignore the second type parameter to Const, the Applicative instance, which has (<*>) :: Monoid m => Const m (a -> b) -> Const m a -> Const m b essentially turns into Monoid m => m -> m -> m, which is (<>)

>>> Const [1, 2, 3] <*> Const [4, 5, 6]
Const [1,2,3,4,5,6]


Constructors

 Const FieldsgetConst :: a

#### Instances

Instances details
Generic1 (Const a :: k -> Type)
Instance details

Defined in GHC.Internal.Data.Functor.Const

Associated Types

 type Rep1 (Const a :: k -> Type) @since base-4.9.0.0 Instance detailsDefined in GHC.Internal.Data.Functor.Const type Rep1 (Const a :: k -> Type) = D1 ('MetaData "Const" "GHC.Internal.Data.Functor.Const" "ghc-internal" 'True) (C1 ('MetaCons "Const" 'PrefixI 'True) (S1 ('MetaSel ('Just "getConst") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 a)))

Methods

from1 :: forall (a0 :: k). Const a a0 -> Rep1 (Const a :: k -> Type) a0 Source #

to1 :: forall (a0 :: k). Rep1 (Const a :: k -> Type) a0 -> Const a a0 Source #

Bifoldable (Const :: Type -> Type -> Type) Source #

Since: base-4.10.0.0

Instance details

Defined in Data.Bifoldable

Methods

bifold :: Monoid m => Const m m -> m Source #

bifoldMap :: Monoid m => (a -> m) -> (b -> m) -> Const a b -> m Source #

bifoldr :: (a -> c -> c) -> (b -> c -> c) -> c -> Const a b -> c Source #

bifoldl :: (c -> a -> c) -> (c -> b -> c) -> c -> Const a b -> c Source #

Bifoldable1 (Const :: Type -> Type -> Type) Source #
Instance details

Defined in Data.Bifoldable1

Methods

bifold1 :: Semigroup m => Const m m -> m Source #

bifoldMap1 :: Semigroup m => (a -> m) -> (b -> m) -> Const a b -> m Source #

Bifunctor (Const :: Type -> Type -> Type) Source #

Since: base-4.8.0.0

Instance details

Defined in Data.Bifunctor

Methods

bimap :: (a -> b) -> (c -> d) -> Const a c -> Const b d Source #

first :: (a -> b) -> Const a c -> Const b c Source #

second :: (b -> c) -> Const a b -> Const a c Source #

Bitraversable (Const :: Type -> Type -> Type) Source #

Since: base-4.10.0.0

Instance details

Defined in Data.Bitraversable

Methods

bitraverse :: Applicative f => (a -> f c) -> (b -> f d) -> Const a b -> f (Const c d) Source #

Eq2 (Const :: Type -> Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

liftEq2 :: (a -> b -> Bool) -> (c -> d -> Bool) -> Const a c -> Const b d -> Bool Source #

Ord2 (Const :: Type -> Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

liftCompare2 :: (a -> b -> Ordering) -> (c -> d -> Ordering) -> Const a c -> Const b d -> Ordering Source #

Read2 (Const :: Type -> Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

Show2 (Const :: Type -> Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

liftShowsPrec2 :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> (Int -> b -> ShowS) -> ([b] -> ShowS) -> Int -> Const a b -> ShowS Source #

liftShowList2 :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> (Int -> b -> ShowS) -> ([b] -> ShowS) -> [Const a b] -> ShowS Source #

Eq a => Eq1 (Const a :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

liftEq :: (a0 -> b -> Bool) -> Const a a0 -> Const a b -> Bool Source #

Ord a => Ord1 (Const a :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

liftCompare :: (a0 -> b -> Ordering) -> Const a a0 -> Const a b -> Ordering Source #

Read a => Read1 (Const a :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

Show a => Show1 (Const a :: Type -> Type) Source #

Since: base-4.9.0.0

Instance details

Defined in Data.Functor.Classes

Methods

liftShowsPrec :: (Int -> a0 -> ShowS) -> ([a0] -> ShowS) -> Int -> Const a a0 -> ShowS Source #

liftShowList :: (Int -> a0 -> ShowS) -> ([a0] -> ShowS) -> [Const a a0] -> ShowS Source #

Contravariant (Const a :: Type -> Type) Source #
Instance details

Defined in Data.Functor.Contravariant

Methods

contramap :: (a' -> a0) -> Const a a0 -> Const a a' Source #

(>$) :: b -> Const a b -> Const a a0 Source # Monoid m => Applicative (Const m :: Type -> Type) @since base-2.0.1 Instance details Defined in GHC.Internal.Data.Functor.Const Methods pure :: a -> Const m a Source # (<*>) :: Const m (a -> b) -> Const m a -> Const m b Source # liftA2 :: (a -> b -> c) -> Const m a -> Const m b -> Const m c Source # (*>) :: Const m a -> Const m b -> Const m b Source # (<*) :: Const m a -> Const m b -> Const m a Source # Functor (Const m :: Type -> Type) @since base-2.01 Instance details Defined in GHC.Internal.Data.Functor.Const Methods fmap :: (a -> b) -> Const m a -> Const m b Source # (<$) :: a -> Const m b -> Const m a Source #

Foldable (Const m :: Type -> Type)

@since base-4.7.0.0

Instance details

Defined in GHC.Internal.Data.Functor.Const

Methods

fold :: Monoid m0 => Const m m0 -> m0 Source #

foldMap :: Monoid m0 => (a -> m0) -> Const m a -> m0 Source #

foldMap' :: Monoid m0 => (a -> m0) -> Const m a -> m0 Source #

foldr :: (a -> b -> b) -> b -> Const m a -> b Source #

foldr' :: (a -> b -> b) -> b -> Const m a -> b Source #

foldl :: (b -> a -> b) -> b -> Const m a -> b Source #

foldl' :: (b -> a -> b) -> b -> Const m a -> b Source #

foldr1 :: (a -> a -> a) -> Const m a -> a Source #

foldl1 :: (a -> a -> a) -> Const m a -> a Source #

toList :: Const m a -> [a] Source #

null :: Const m a -> Bool Source #

length :: Const m a -> Int Source #

elem :: Eq a => a -> Const m a -> Bool Source #

maximum :: Ord a => Const m a -> a Source #

minimum :: Ord a => Const m a -> a Source #

sum :: Num a => Const m a -> a Source #

product :: Num a => Const m a -> a Source #

Traversable (Const m :: Type -> Type)

@since base-4.7.0.0

Instance details

Defined in GHC.Internal.Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> Const m a -> f (Const m b) Source #

sequenceA :: Applicative f => Const m (f a) -> f (Const m a) Source #

mapM :: Monad m0 => (a -> m0 b) -> Const m a -> m0 (Const m b) Source #

sequence :: Monad m0 => Const m (m0 a) -> m0 (Const m a) Source #

Monoid a => Monoid (Const a b)

@since base-4.9.0.0

Instance details

Defined in GHC.Internal.Data.Functor.Const

Methods

mempty :: Const a b Source #

mappend :: Const a b -> Const a b -> Const a b Source #

mconcat :: [Const a b] -> Const a b Source #

Semigroup a => Semigroup (Const a b)

@since base-4.9.0.0

Instance details

Defined in GHC.Internal.Data.Functor.Const

Methods

(<>) :: Const a b -> Const a b -> Const a b Source #

sconcat :: NonEmpty (Const a b) -> Const a b Source #

stimes :: Integral b0 => b0 -> Const a b -> Const a b Source #

Bits a => Bits (Const a b)

@since base-4.9.0.0

Instance details

Defined in GHC.Internal.Data.Functor.Const

Methods

(.&.) :: Const a b -> Const a b -> Const a b Source #

(.|.) :: Const a b -> Const a b -> Const a b Source #

xor :: Const a b -> Const a b -> Const a b Source #

complement :: Const a b -> Const a b Source #

shift :: Const a b -> Int -> Const a b Source #

rotate :: Const a b -> Int -> Const a b Source #

zeroBits :: Const a b Source #

bit :: Int -> Const a b Source #

setBit :: Const a b -> Int -> Const a b Source #

clearBit :: Const a b -> Int -> Const a b Source #

complementBit :: Const a b -> Int -> Const a b Source #

testBit :: Const a b -> Int -> Bool Source #

bitSizeMaybe :: Const a b -> Maybe Int Source #

bitSize :: Const a b -> Int Source #

isSigned :: Const a b -> Bool Source #

shiftL :: Const a b -> Int -> Const a b Source #

unsafeShiftL :: Const a b -> Int -> Const a b Source #

shiftR :: Const a b -> Int -> Const a b Source #

unsafeShiftR :: Const a b -> Int -> Const a b Source #

rotateL :: Const a b -> Int -> Const a b Source #

rotateR :: Const a b -> Int -> Const a b Source #

popCount :: Const a b -> Int Source #

FiniteBits a => FiniteBits (Const a b)

@since base-4.9.0.0

Instance details

Defined in GHC.Internal.Data.Functor.Const

(Typeable k, Data a, Typeable b) => Data (Const a b)

@since base-4.10.0.0

Instance details

Defined in GHC.Internal.Data.Data

Methods

gfoldl :: (forall d b0. Data d => c (d -> b0) -> d -> c b0) -> (forall g. g -> c g) -> Const a b -> c (Const a b) Source #

gunfold :: (forall b0 r. Data b0 => c (b0 -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Const a b) Source #

toConstr :: Const a b -> Constr Source #

dataTypeOf :: Const a b -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (Const a b)) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Const a b)) Source #

gmapT :: (forall b0. Data b0 => b0 -> b0) -> Const a b -> Const a b Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Const a b -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Const a b -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> Const a b -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> Const a b -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> Const a b -> m (Const a b) Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Const a b -> m (Const a b) Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Const a b -> m (Const a b) Source #

IsString a => IsString (Const a b)

@since base-4.9.0.0

Instance details

Defined in GHC.Internal.Data.String

Methods

fromString :: String -> Const a b Source #

Bounded a => Bounded (Const a b)

@since base-4.9.0.0

Instance details

Defined in GHC.Internal.Data.Functor.Const

Methods

minBound :: Const a b Source #

maxBound :: Const a b Source #

Enum a => Enum (Const a b)

@since base-4.9.0.0

Instance details

Defined in GHC.Internal.Data.Functor.Const

Methods

succ :: Const a b -> Const a b Source #

pred :: Const a b -> Const a b Source #

toEnum :: Int -> Const a b Source #

fromEnum :: Const a b -> Int Source #

enumFrom :: Const a b -> [Const a b] Source #

enumFromThen :: Const a b -> Const a b -> [Const a b] Source #

enumFromTo :: Const a b -> Const a b -> [Const a b] Source #

enumFromThenTo :: Const a b -> Const a b -> Const a b -> [Const a b] Source #

Floating a => Floating (Const a b)

@since base-4.9.0.0

Instance details

Defined in GHC.Internal.Data.Functor.Const

Methods

pi :: Const a b Source #

exp :: Const a b -> Const a b Source #

log :: Const a b -> Const a b Source #

sqrt :: Const a b -> Const a b Source #

(**) :: Const a b -> Const a b -> Const a b Source #

logBase :: Const a b -> Const a b -> Const a b Source #

sin :: Const a b -> Const a b Source #

cos :: Const a b -> Const a b Source #

tan :: Const a b -> Const a b Source #

asin :: Const a b -> Const a b Source #

acos :: Const a b -> Const a b Source #

atan :: Const a b -> Const a b Source #

sinh :: Const a b -> Const a b Source #

cosh :: Const a b -> Const a b Source #

tanh :: Const a b -> Const a b Source #

asinh :: Const a b -> Const a b Source #

acosh :: Const a b -> Const a b Source #

atanh :: Const a b -> Const a b Source #

log1p :: Const a b -> Const a b Source #

expm1 :: Const a b -> Const a b Source #

log1pexp :: Const a b -> Const a b Source #

log1mexp :: Const a b -> Const a b Source #

RealFloat a => RealFloat (Const a b)

@since base-4.9.0.0

Instance details

Defined in GHC.Internal.Data.Functor.Const

Storable a => Storable (Const a b)

@since base-4.9.0.0

Instance details

Defined in GHC.Internal.Data.Functor.Const

Methods

sizeOf :: Const a b -> Int Source #

alignment :: Const a b -> Int Source #

peekElemOff :: Ptr (Const a b) -> Int -> IO (Const a b) Source #

pokeElemOff :: Ptr (Const a b) -> Int -> Const a b -> IO () Source #

peekByteOff :: Ptr b0 -> Int -> IO (Const a b) Source #

pokeByteOff :: Ptr b0 -> Int -> Const a b -> IO () Source #

peek :: Ptr (Const a b) -> IO (Const a b) Source #

poke :: Ptr (Const a b) -> Const a b -> IO () Source #

Generic (Const a b)
Instance details

Defined in GHC.Internal.Data.Functor.Const

Associated Types

 type Rep (Const a b) @since base-4.9.0.0 Instance detailsDefined in GHC.Internal.Data.Functor.Const type Rep (Const a b) = D1 ('MetaData "Const" "GHC.Internal.Data.Functor.Const" "ghc-internal" 'True) (C1 ('MetaCons "Const" 'PrefixI 'True) (S1 ('MetaSel ('Just "getConst") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 a)))

Methods

from :: Const a b -> Rep (Const a b) x Source #

to :: Rep (Const a b) x -> Const a b Source #

Ix a => Ix (Const a b)

@since base-4.9.0.0

Instance details

Defined in GHC.Internal.Data.Functor.Const

Methods

range :: (Const a b, Const a b) -> [Const a b] Source #

index :: (Const a b, Const a b) -> Const a b -> Int Source #

unsafeIndex :: (Const a b, Const a b) -> Const a b -> Int Source #

inRange :: (Const a b, Const a b) -> Const a b -> Bool Source #

rangeSize :: (Const a b, Const a b) -> Int Source #

unsafeRangeSize :: (Const a b, Const a b) -> Int Source #

Num a => Num (Const a b)

@since base-4.9.0.0

Instance details

Defined in GHC.Internal.Data.Functor.Const

Methods

(+) :: Const a b -> Const a b -> Const a b Source #

(-) :: Const a b -> Const a b -> Const a b Source #

(*) :: Const a b -> Const a b -> Const a b Source #

negate :: Const a b -> Const a b Source #

abs :: Const a b -> Const a b Source #

signum :: Const a b -> Const a b Source #

This instance would be equivalent to the derived instances of the Const newtype if the getConst field were removed

@since base-4.8.0.0

Instance details

Defined in GHC.Internal.Data.Functor.Const

Fractional a => Fractional (Const a b)

@since base-4.9.0.0

Instance details

Defined in GHC.Internal.Data.Functor.Const

Methods

(/) :: Const a b -> Const a b -> Const a b Source #

recip :: Const a b -> Const a b Source #

Integral a => Integral (Const a b)

@since base-4.9.0.0

Instance details

Defined in GHC.Internal.Data.Functor.Const

Methods

quot :: Const a b -> Const a b -> Const a b Source #

rem :: Const a b -> Const a b -> Const a b Source #

div :: Const a b -> Const a b -> Const a b Source #

mod :: Const a b -> Const a b -> Const a b Source #

quotRem :: Const a b -> Const a b -> (Const a b, Const a b) Source #

divMod :: Const a b -> Const a b -> (Const a b, Const a b) Source #

toInteger :: Const a b -> Integer Source #

Real a => Real (Const a b)

@since base-4.9.0.0

Instance details

Defined in GHC.Internal.Data.Functor.Const

Methods

toRational :: Const a b -> Rational Source #

RealFrac a => RealFrac (Const a b)

@since base-4.9.0.0

Instance details

Defined in GHC.Internal.Data.Functor.Const

Methods

properFraction :: Integral b0 => Const a b -> (b0, Const a b) Source #

truncate :: Integral b0 => Const a b -> b0 Source #

round :: Integral b0 => Const a b -> b0 Source #

ceiling :: Integral b0 => Const a b -> b0 Source #

floor :: Integral b0 => Const a b -> b0 Source #

Show a => Show (Const a b)

This instance would be equivalent to the derived instances of the Const newtype if the getConst field were removed

@since base-4.8.0.0

Instance details

Defined in GHC.Internal.Data.Functor.Const

Methods

showsPrec :: Int -> Const a b -> ShowS Source #

show :: Const a b -> String Source #

showList :: [Const a b] -> ShowS Source #

Eq a => Eq (Const a b)

@since base-4.9.0.0

Instance details

Defined in GHC.Internal.Data.Functor.Const

Methods

(==) :: Const a b -> Const a b -> Bool Source #

(/=) :: Const a b -> Const a b -> Bool Source #

Ord a => Ord (Const a b)

@since base-4.9.0.0

Instance details

Defined in GHC.Internal.Data.Functor.Const

Methods

compare :: Const a b -> Const a b -> Ordering Source #

(<) :: Const a b -> Const a b -> Bool Source #

(<=) :: Const a b -> Const a b -> Bool Source #

(>) :: Const a b -> Const a b -> Bool Source #

(>=) :: Const a b -> Const a b -> Bool Source #

max :: Const a b -> Const a b -> Const a b Source #

min :: Const a b -> Const a b -> Const a b Source #

type Rep1 (Const a :: k -> Type)

@since base-4.9.0.0

Instance details

Defined in GHC.Internal.Data.Functor.Const

type Rep1 (Const a :: k -> Type) = D1 ('MetaData "Const" "GHC.Internal.Data.Functor.Const" "ghc-internal" 'True) (C1 ('MetaCons "Const" 'PrefixI 'True) (S1 ('MetaSel ('Just "getConst") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 a)))
type Rep (Const a b)

@since base-4.9.0.0

Instance details

Defined in GHC.Internal.Data.Functor.Const

type Rep (Const a b) = D1 ('MetaData "Const" "GHC.Internal.Data.Functor.Const" "ghc-internal" 'True) (C1 ('MetaCons "Const" 'PrefixI 'True) (S1 ('MetaSel ('Just "getConst") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 a)))

newtype WrappedMonad (m :: Type -> Type) a Source #

Constructors

#### Instances

Instances details
Generic1 (WrappedMonad m :: Type -> Type) Source #
Instance details

Defined in Control.Applicative

Associated Types

 type Rep1 (WrappedMonad m :: Type -> Type) Since: base-4.7.0.0 Instance detailsDefined in Control.Applicative type Rep1 (WrappedMonad m :: Type -> Type) = D1 ('MetaData "WrappedMonad" "Control.Applicative" "base" 'True) (C1 ('MetaCons "WrapMonad" 'PrefixI 'True) (S1 ('MetaSel ('Just "unwrapMonad") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec1 m)))
Source #

Since: base-2.1

Instance details

Defined in Control.Applicative

Since: base-2.1

Instance details

Defined in Control.Applicative

Methods

pure :: a -> WrappedMonad m a Source #

(<*>) :: WrappedMonad m (a -> b) -> WrappedMonad m a -> WrappedMonad m b Source #

liftA2 :: (a -> b -> c) -> WrappedMonad m a -> WrappedMonad m b -> WrappedMonad m c Source #

Since: base-2.1

Instance details

Defined in Control.Applicative

Methods

fmap :: (a -> b) -> WrappedMonad m a -> WrappedMonad m b Source #

(<$) :: a -> WrappedMonad m b -> WrappedMonad m a Source # Monad m => Monad (WrappedMonad m) Source # Since: base-4.7.0.0 Instance details Defined in Control.Applicative Methods (>>=) :: WrappedMonad m a -> (a -> WrappedMonad m b) -> WrappedMonad m b Source # (>>) :: WrappedMonad m a -> WrappedMonad m b -> WrappedMonad m b Source # return :: a -> WrappedMonad m a Source # (Typeable m, Typeable a, Data (m a)) => Data (WrappedMonad m a) Source # Since: base-4.14.0.0 Instance details Defined in Control.Applicative Methods gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> WrappedMonad m a -> c (WrappedMonad m a) Source # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (WrappedMonad m a) Source # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (WrappedMonad m a)) Source # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (WrappedMonad m a)) Source # gmapT :: (forall b. Data b => b -> b) -> WrappedMonad m a -> WrappedMonad m a Source # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> WrappedMonad m a -> r Source # gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> WrappedMonad m a -> r Source # gmapQ :: (forall d. Data d => d -> u) -> WrappedMonad m a -> [u] Source # gmapQi :: Int -> (forall d. Data d => d -> u) -> WrappedMonad m a -> u Source # gmapM :: Monad m0 => (forall d. Data d => d -> m0 d) -> WrappedMonad m a -> m0 (WrappedMonad m a) Source # gmapMp :: MonadPlus m0 => (forall d. Data d => d -> m0 d) -> WrappedMonad m a -> m0 (WrappedMonad m a) Source # gmapMo :: MonadPlus m0 => (forall d. Data d => d -> m0 d) -> WrappedMonad m a -> m0 (WrappedMonad m a) Source # Generic (WrappedMonad m a) Source # Instance details Defined in Control.Applicative Associated Types  type Rep (WrappedMonad m a) Since: base-4.7.0.0 Instance detailsDefined in Control.Applicative type Rep (WrappedMonad m a) = D1 ('MetaData "WrappedMonad" "Control.Applicative" "base" 'True) (C1 ('MetaCons "WrapMonad" 'PrefixI 'True) (S1 ('MetaSel ('Just "unwrapMonad") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 (m a)))) Methods from :: WrappedMonad m a -> Rep (WrappedMonad m a) x Source # to :: Rep (WrappedMonad m a) x -> WrappedMonad m a Source # type Rep1 (WrappedMonad m :: Type -> Type) Source # Since: base-4.7.0.0 Instance details Defined in Control.Applicative type Rep1 (WrappedMonad m :: Type -> Type) = D1 ('MetaData "WrappedMonad" "Control.Applicative" "base" 'True) (C1 ('MetaCons "WrapMonad" 'PrefixI 'True) (S1 ('MetaSel ('Just "unwrapMonad") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec1 m))) type Rep (WrappedMonad m a) Source # Since: base-4.7.0.0 Instance details Defined in Control.Applicative type Rep (WrappedMonad m a) = D1 ('MetaData "WrappedMonad" "Control.Applicative" "base" 'True) (C1 ('MetaCons "WrapMonad" 'PrefixI 'True) (S1 ('MetaSel ('Just "unwrapMonad") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 (m a)))) newtype WrappedArrow (a :: Type -> Type -> Type) b c Source # Constructors  WrapArrow FieldsunwrapArrow :: a b c #### Instances Instances details Generic1 (WrappedArrow a b :: Type -> Type) Source # Instance details Defined in Control.Applicative Associated Types  type Rep1 (WrappedArrow a b :: Type -> Type) Since: base-4.7.0.0 Instance detailsDefined in Control.Applicative type Rep1 (WrappedArrow a b :: Type -> Type) = D1 ('MetaData "WrappedArrow" "Control.Applicative" "base" 'True) (C1 ('MetaCons "WrapArrow" 'PrefixI 'True) (S1 ('MetaSel ('Just "unwrapArrow") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec1 (a b)))) Methods from1 :: WrappedArrow a b a0 -> Rep1 (WrappedArrow a b) a0 Source # to1 :: Rep1 (WrappedArrow a b) a0 -> WrappedArrow a b a0 Source # (ArrowZero a, ArrowPlus a) => Alternative (WrappedArrow a b) Source # Since: base-2.1 Instance details Defined in Control.Applicative Methods empty :: WrappedArrow a b a0 Source # (<|>) :: WrappedArrow a b a0 -> WrappedArrow a b a0 -> WrappedArrow a b a0 Source # some :: WrappedArrow a b a0 -> WrappedArrow a b [a0] Source # many :: WrappedArrow a b a0 -> WrappedArrow a b [a0] Source # Arrow a => Applicative (WrappedArrow a b) Source # Since: base-2.1 Instance details Defined in Control.Applicative Methods pure :: a0 -> WrappedArrow a b a0 Source # (<*>) :: WrappedArrow a b (a0 -> b0) -> WrappedArrow a b a0 -> WrappedArrow a b b0 Source # liftA2 :: (a0 -> b0 -> c) -> WrappedArrow a b a0 -> WrappedArrow a b b0 -> WrappedArrow a b c Source # (*>) :: WrappedArrow a b a0 -> WrappedArrow a b b0 -> WrappedArrow a b b0 Source # (<*) :: WrappedArrow a b a0 -> WrappedArrow a b b0 -> WrappedArrow a b a0 Source # Arrow a => Functor (WrappedArrow a b) Source # Since: base-2.1 Instance details Defined in Control.Applicative Methods fmap :: (a0 -> b0) -> WrappedArrow a b a0 -> WrappedArrow a b b0 Source # (<$) :: a0 -> WrappedArrow a b b0 -> WrappedArrow a b a0 Source #

(Typeable a, Typeable b, Typeable c, Data (a b c)) => Data (WrappedArrow a b c) Source #

Since: base-4.14.0.0

Instance details

Defined in Control.Applicative

Methods

gfoldl :: (forall d b0. Data d => c0 (d -> b0) -> d -> c0 b0) -> (forall g. g -> c0 g) -> WrappedArrow a b c -> c0 (WrappedArrow a b c) Source #

gunfold :: (forall b0 r. Data b0 => c0 (b0 -> r) -> c0 r) -> (forall r. r -> c0 r) -> Constr -> c0 (WrappedArrow a b c) Source #

toConstr :: WrappedArrow a b c -> Constr Source #

dataTypeOf :: WrappedArrow a b c -> DataType Source #

dataCast1 :: Typeable t => (forall d. Data d => c0 (t d)) -> Maybe (c0 (WrappedArrow a b c)) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c0 (t d e)) -> Maybe (c0 (WrappedArrow a b c)) Source #

gmapT :: (forall b0. Data b0 => b0 -> b0) -> WrappedArrow a b c -> WrappedArrow a b c Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> WrappedArrow a b c -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> WrappedArrow a b c -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> WrappedArrow a b c -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> WrappedArrow a b c -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> WrappedArrow a b c -> m (WrappedArrow a b c) Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> WrappedArrow a b c -> m (WrappedArrow a b c) Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> WrappedArrow a b c -> m (WrappedArrow a b c) Source #

Generic (WrappedArrow a b c) Source #
Instance details

Defined in Control.Applicative

Associated Types

 type Rep (WrappedArrow a b c) Since: base-4.7.0.0 Instance detailsDefined in Control.Applicative type Rep (WrappedArrow a b c) = D1 ('MetaData "WrappedArrow" "Control.Applicative" "base" 'True) (C1 ('MetaCons "WrapArrow" 'PrefixI 'True) (S1 ('MetaSel ('Just "unwrapArrow") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 (a b c))))

Methods

from :: WrappedArrow a b c -> Rep (WrappedArrow a b c) x Source #

to :: Rep (WrappedArrow a b c) x -> WrappedArrow a b c Source #

type Rep1 (WrappedArrow a b :: Type -> Type) Source #

Since: base-4.7.0.0

Instance details

Defined in Control.Applicative

type Rep1 (WrappedArrow a b :: Type -> Type) = D1 ('MetaData "WrappedArrow" "Control.Applicative" "base" 'True) (C1 ('MetaCons "WrapArrow" 'PrefixI 'True) (S1 ('MetaSel ('Just "unwrapArrow") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec1 (a b))))
type Rep (WrappedArrow a b c) Source #

Since: base-4.7.0.0

Instance details

Defined in Control.Applicative

type Rep (WrappedArrow a b c) = D1 ('MetaData "WrappedArrow" "Control.Applicative" "base" 'True) (C1 ('MetaCons "WrapArrow" 'PrefixI 'True) (S1 ('MetaSel ('Just "unwrapArrow") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 (a b c))))

newtype ZipList a Source #

Lists, but with an Applicative functor based on zipping.

#### Examples

Expand

In contrast to the Applicative for List:

>>> (+) <$> [1, 2, 3] <*> [4, 5, 6] [5,6,7,6,7,8,7,8,9]  The Applicative instance of ZipList applies the operation by pairing up the elements, analogous to zipWithN >>> (+) <$> ZipList [1, 2, 3] <*> ZipList [4, 5, 6]
ZipList {getZipList = [5,7,9]}

>>> (,,,) <$> ZipList [1, 2] <*> ZipList [3, 4] <*> ZipList [5, 6] <*> ZipList [7, 8] ZipList {getZipList = [(1,3,5,7),(2,4,6,8)]}  >>> ZipList [(+1), (^2), (/ 2)] <*> ZipList [5, 5, 5] ZipList {getZipList = [6.0,25.0,2.5]}  Constructors  ZipList FieldsgetZipList :: [a] #### Instances Instances details @since base-4.11.0.0 Instance details Defined in GHC.Internal.Functor.ZipList Methods (<|>) :: ZipList a -> ZipList a -> ZipList a Source # some :: ZipList a -> ZipList [a] Source # many :: ZipList a -> ZipList [a] Source # f <$> ZipList xs1 <*> ... <*> ZipList xsN
= ZipList (zipWithN f xs1 ... xsN)

where zipWithN refers to the zipWith function of the appropriate arity (zipWith, zipWith3, zipWith4, ...). For example:

(\a b c -> stimes c [a, b]) <$> ZipList "abcd" <*> ZipList "567" <*> ZipList [1..] = ZipList (zipWith3 (\a b c -> stimes c [a, b]) "abcd" "567" [1..]) = ZipList {getZipList = ["a5","b6b6","c7c7c7"]} @since base-2.01 Instance details Defined in GHC.Internal.Functor.ZipList Methods pure :: a -> ZipList a Source # (<*>) :: ZipList (a -> b) -> ZipList a -> ZipList b Source # liftA2 :: (a -> b -> c) -> ZipList a -> ZipList b -> ZipList c Source # (*>) :: ZipList a -> ZipList b -> ZipList b Source # (<*) :: ZipList a -> ZipList b -> ZipList a Source # @since base-2.01 Instance details Defined in GHC.Internal.Functor.ZipList Methods fmap :: (a -> b) -> ZipList a -> ZipList b Source # (<$) :: a -> ZipList b -> ZipList a Source #

@since base-4.9.0.0

Instance details

Defined in GHC.Internal.Functor.ZipList

Methods

fold :: Monoid m => ZipList m -> m Source #

foldMap :: Monoid m => (a -> m) -> ZipList a -> m Source #

foldMap' :: Monoid m => (a -> m) -> ZipList a -> m Source #

foldr :: (a -> b -> b) -> b -> ZipList a -> b Source #

foldr' :: (a -> b -> b) -> b -> ZipList a -> b Source #

foldl :: (b -> a -> b) -> b -> ZipList a -> b Source #

foldl' :: (b -> a -> b) -> b -> ZipList a -> b Source #

foldr1 :: (a -> a -> a) -> ZipList a -> a Source #

foldl1 :: (a -> a -> a) -> ZipList a -> a Source #

toList :: ZipList a -> [a] Source #

null :: ZipList a -> Bool Source #

length :: ZipList a -> Int Source #

elem :: Eq a => a -> ZipList a -> Bool Source #

maximum :: Ord a => ZipList a -> a Source #

minimum :: Ord a => ZipList a -> a Source #

sum :: Num a => ZipList a -> a Source #

product :: Num a => ZipList a -> a Source #

@since base-4.9.0.0

Instance details

Defined in GHC.Internal.Functor.ZipList

Methods

traverse :: Applicative f => (a -> f b) -> ZipList a -> f (ZipList b) Source #

sequenceA :: Applicative f => ZipList (f a) -> f (ZipList a) Source #

mapM :: Monad m => (a -> m b) -> ZipList a -> m (ZipList b) Source #

sequence :: Monad m => ZipList (m a) -> m (ZipList a) Source #

Instance details

Defined in GHC.Internal.Functor.ZipList

Associated Types

 type Rep1 ZipList @since base-4.7.0.0 Instance detailsDefined in GHC.Internal.Functor.ZipList type Rep1 ZipList = D1 ('MetaData "ZipList" "GHC.Internal.Functor.ZipList" "ghc-internal" 'True) (C1 ('MetaCons "ZipList" 'PrefixI 'True) (S1 ('MetaSel ('Just "getZipList") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec1 [])))

Methods

to1 :: Rep1 ZipList a -> ZipList a Source #

Data a => Data (ZipList a)

@since base-4.14.0.0

Instance details

Defined in GHC.Internal.Functor.ZipList

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> ZipList a -> c (ZipList a) Source #

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (ZipList a) Source #

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (ZipList a)) Source #

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (ZipList a)) Source #

gmapT :: (forall b. Data b => b -> b) -> ZipList a -> ZipList a Source #

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> ZipList a -> r Source #

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> ZipList a -> r Source #

gmapQ :: (forall d. Data d => d -> u) -> ZipList a -> [u] Source #

gmapQi :: Int -> (forall d. Data d => d -> u) -> ZipList a -> u Source #

gmapM :: Monad m => (forall d. Data d => d -> m d) -> ZipList a -> m (ZipList a) Source #

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> ZipList a -> m (ZipList a) Source #

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> ZipList a -> m (ZipList a) Source #

Instance details

Defined in GHC.Internal.Functor.ZipList

Associated Types

 type Rep (ZipList a) @since base-4.7.0.0 Instance detailsDefined in GHC.Internal.Functor.ZipList type Rep (ZipList a) = D1 ('MetaData "ZipList" "GHC.Internal.Functor.ZipList" "ghc-internal" 'True) (C1 ('MetaCons "ZipList" 'PrefixI 'True) (S1 ('MetaSel ('Just "getZipList") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 [a])))

Methods

from :: ZipList a -> Rep (ZipList a) x Source #

to :: Rep (ZipList a) x -> ZipList a Source #

@since base-4.15.0.0

Instance details

Defined in GHC.Internal.IsList

Associated Types

 type Item (ZipList a) Instance detailsDefined in GHC.Internal.IsList type Item (ZipList a) = a

Methods

fromList :: [Item (ZipList a)] -> ZipList a Source #

fromListN :: Int -> [Item (ZipList a)] -> ZipList a Source #

toList :: ZipList a -> [Item (ZipList a)] Source #

@since base-4.7.0.0

Instance details

Defined in GHC.Internal.Functor.ZipList

Methods

Show a => Show (ZipList a)

@since base-4.7.0.0

Instance details

Defined in GHC.Internal.Functor.ZipList

Eq a => Eq (ZipList a)

@since base-4.7.0.0

Instance details

Defined in GHC.Internal.Functor.ZipList

Methods

(==) :: ZipList a -> ZipList a -> Bool Source #

(/=) :: ZipList a -> ZipList a -> Bool Source #

Ord a => Ord (ZipList a)

@since base-4.7.0.0

Instance details

Defined in GHC.Internal.Functor.ZipList

type Rep1 ZipList

@since base-4.7.0.0

Instance details

Defined in GHC.Internal.Functor.ZipList

type Rep1 ZipList = D1 ('MetaData "ZipList" "GHC.Internal.Functor.ZipList" "ghc-internal" 'True) (C1 ('MetaCons "ZipList" 'PrefixI 'True) (S1 ('MetaSel ('Just "getZipList") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec1 [])))
type Rep (ZipList a)

@since base-4.7.0.0

Instance details

Defined in GHC.Internal.Functor.ZipList

type Rep (ZipList a) = D1 ('MetaData "ZipList" "GHC.Internal.Functor.ZipList" "ghc-internal" 'True) (C1 ('MetaCons "ZipList" 'PrefixI 'True) (S1 ('MetaSel ('Just "getZipList") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 [a])))
type Item (ZipList a)
Instance details

Defined in GHC.Internal.IsList

type Item (ZipList a) = a

# Utility functions

(<$>) :: Functor f => (a -> b) -> f a -> f b infixl 4 Source # An infix synonym for fmap. The name of this operator is an allusion to $. Note the similarities between their types:

 ($) :: (a -> b) -> a -> b (<$>) :: Functor f => (a -> b) -> f a -> f b

Whereas $ is function application, <$> is function application lifted over a Functor.

#### Examples

Expand

Convert from a Maybe Int to a Maybe String using show:

>>> show <$> Nothing Nothing  >>> show <$> Just 3
Just "3"


Convert from an Either Int Int to an Either Int String using show:

>>> show <$> Left 17 Left 17  >>> show <$> Right 17
Right "17"


Double each element of a list:

>>> (*2) <$> [1,2,3] [2,4,6]  Apply even to the second element of a pair: >>> even <$> (2,2)
(2,True)


(<$) :: Functor f => a -> f b -> f a infixl 4 Source # Replace all locations in the input with the same value. The default definition is fmap . const, but this may be overridden with a more efficient version. #### Examples Expand Perform a computation with Maybe and replace the result with a constant value if it is Just: >>> 'a' <$ Just 2
Just 'a'
>>> 'a' <$Nothing Nothing  (<**>) :: Applicative f => f a -> f (a -> b) -> f b infixl 4 Source # A variant of <*> with the types of the arguments reversed. It differs from flip (<*>) in that the effects are resolved in the order the arguments are presented. #### Examples Expand >>> (<**>) (print 1) (id <$ print 2)
1
2

>>> flip (<*>) (print 1) (id <$print 2) 2 1  >>> ZipList [4, 5, 6] <**> ZipList [(+1), (*2), (/3)] ZipList {getZipList = [5.0,10.0,2.0]}  liftA :: Applicative f => (a -> b) -> f a -> f b Source # Lift a function to actions. Equivalent to Functor's fmap but implemented using only Applicative's methods: liftA f a = pure f <*> a As such this function may be used to implement a Functor instance from an Applicative one. #### Examples Expand Using the Applicative instance for Lists: >>> liftA (+1) [1, 2] [2,3]  Or the Applicative instance for Maybe >>> liftA (+1) (Just 3) Just 4  liftA3 :: Applicative f => (a -> b -> c -> d) -> f a -> f b -> f c -> f d Source # Lift a ternary function to actions. optional :: Alternative f => f a -> f (Maybe a) Source # One or none. It is useful for modelling any computation that is allowed to fail. #### Examples Expand Using the Alternative instance of Control.Monad.Except, the following functions: >>> import Control.Monad.Except  >>> canFail = throwError "it failed" :: Except String Int >>> final = return 42 :: Except String Int  Can be combined by allowing the first function to fail: >>> runExcept$ canFail *> final
Left "it failed"

>>> runExcept \$ optional canFail *> final
Right 42


asum :: (Foldable t, Alternative f) => t (f a) -> f a Source #

The sum of a collection of actions using (<|>), generalizing concat.

asum is just like msum, but generalised to Alternative.

#### Examples

Expand

Basic usage:

>>> asum [Just "Hello", Nothing, Just "World"]
Just "Hello"