{-# LANGUAGE Trustworthy #-}{-# LANGUAGE DeriveGeneric #-}{-# LANGUAGE GeneralizedNewtypeDeriving #-}{-# LANGUAGE NoImplicitPrelude #-}------------------------------------------------------------------------------- |-- Module : Control.Applicative-- Copyright : Conor McBride and Ross Paterson 2005-- License : BSD-style (see the LICENSE file in the distribution)---- Maintainer : libraries@haskell.org-- Stability : stable-- Portability : portable---- 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-- 'Data.Traversable.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-- <http://www.soi.city.ac.uk/~ross/papers/Applicative.html Applicative Programming with Effects>,-- by Conor McBride and Ross Paterson.moduleControl.Applicative(-- * Applicative functorsApplicative (..),-- * AlternativesAlternative (..),-- * InstancesConst (..),WrappedMonad (..),WrappedArrow (..),ZipList (..),-- * Utility functions(<$>) ,(<$) ,(<**>) ,liftA ,liftA3 ,optional ,asum ,)whereimportControl.Category hiding((.) ,id )importControl.Arrow importData.Maybe importData.Tuple importData.Eq importData.Ord importData.Foldable (Foldable (..),asum )importData.Functor ((<$>) )importData.Functor.Const (Const (..))importGHC.Base importGHC.Generics importGHC.List (repeat ,zipWith )importGHC.Read (Read )importGHC.Show (Show )-- $setup-- >>> import PreludenewtypeWrappedMonad m a =WrapMonad {forall (m :: * -> *) a. WrappedMonad m a -> m a unwrapMonad ::m a }deriving((forall x. WrappedMonad m a -> Rep (WrappedMonad m a) x) -> (forall x. Rep (WrappedMonad m a) x -> WrappedMonad m a) -> Generic (WrappedMonad m a) forall x. Rep (WrappedMonad m a) x -> WrappedMonad m a forall x. WrappedMonad m a -> Rep (WrappedMonad m a) x forall a. (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a forall (m :: * -> *) a x. Rep (WrappedMonad m a) x -> WrappedMonad m a forall (m :: * -> *) a x. WrappedMonad m a -> Rep (WrappedMonad m a) x $cfrom :: forall (m :: * -> *) a x. WrappedMonad m a -> Rep (WrappedMonad m a) x from :: forall x. WrappedMonad m a -> Rep (WrappedMonad m a) x $cto :: forall (m :: * -> *) a x. Rep (WrappedMonad m a) x -> WrappedMonad m a to :: forall x. Rep (WrappedMonad m a) x -> WrappedMonad m a Generic -- ^ @since 4.7.0.0,(forall a. WrappedMonad m a -> Rep1 (WrappedMonad m) a) -> (forall a. Rep1 (WrappedMonad m) a -> WrappedMonad m a) -> Generic1 (WrappedMonad m) forall a. Rep1 (WrappedMonad m) a -> WrappedMonad m a forall a. WrappedMonad m a -> Rep1 (WrappedMonad m) a forall k (f :: k -> *). (forall (a :: k). f a -> Rep1 f a) -> (forall (a :: k). Rep1 f a -> f a) -> Generic1 f forall (m :: * -> *) a. Rep1 (WrappedMonad m) a -> WrappedMonad m a forall (m :: * -> *) a. WrappedMonad m a -> Rep1 (WrappedMonad m) a $cfrom1 :: forall (m :: * -> *) a. WrappedMonad m a -> Rep1 (WrappedMonad m) a from1 :: forall a. WrappedMonad m a -> Rep1 (WrappedMonad m) a $cto1 :: forall (m :: * -> *) a. Rep1 (WrappedMonad m) a -> WrappedMonad m a to1 :: forall a. Rep1 (WrappedMonad m) a -> WrappedMonad m a Generic1 -- ^ @since 4.7.0.0,Applicative (WrappedMonad m) Applicative (WrappedMonad m) => (forall a b. WrappedMonad m a -> (a -> WrappedMonad m b) -> WrappedMonad m b) -> (forall a b. WrappedMonad m a -> WrappedMonad m b -> WrappedMonad m b) -> (forall a. a -> WrappedMonad m a) -> Monad (WrappedMonad m) forall a. a -> WrappedMonad m a forall a b. WrappedMonad m a -> WrappedMonad m b -> WrappedMonad m b forall a b. WrappedMonad m a -> (a -> WrappedMonad m b) -> WrappedMonad m b forall (m :: * -> *). Monad m => Applicative (WrappedMonad m) forall (m :: * -> *) a. Monad m => a -> WrappedMonad m a forall (m :: * -> *) a b. Monad m => WrappedMonad m a -> WrappedMonad m b -> WrappedMonad m b forall (m :: * -> *) a b. Monad m => WrappedMonad m a -> (a -> WrappedMonad m b) -> WrappedMonad m b forall (m :: * -> *). Applicative m => (forall a b. m a -> (a -> m b) -> m b) -> (forall a b. m a -> m b -> m b) -> (forall a. a -> m a) -> Monad m $c>>= :: forall (m :: * -> *) a b. Monad m => WrappedMonad m a -> (a -> WrappedMonad m b) -> WrappedMonad m b >>= :: forall a b. WrappedMonad m a -> (a -> WrappedMonad m b) -> WrappedMonad m b $c>> :: forall (m :: * -> *) a b. Monad m => WrappedMonad m a -> WrappedMonad m b -> WrappedMonad m b >> :: forall a b. WrappedMonad m a -> WrappedMonad m b -> WrappedMonad m b $creturn :: forall (m :: * -> *) a. Monad m => a -> WrappedMonad m a return :: forall a. a -> WrappedMonad m a Monad -- ^ @since 4.7.0.0)-- | @since 2.01instanceMonad m =>Functor (WrappedMonad m )wherefmap :: forall a b. (a -> b) -> WrappedMonad m a -> WrappedMonad m b fmap a -> b f (WrapMonad m a v )=m b -> WrappedMonad m b forall (m :: * -> *) a. m a -> WrappedMonad m a WrapMonad ((a -> b) -> m a -> m b forall (m :: * -> *) a1 r. Monad m => (a1 -> r) -> m a1 -> m r liftM a -> b f m a v )-- | @since 2.01instanceMonad m =>Applicative (WrappedMonad m )wherepure :: forall a. a -> WrappedMonad m a pure =m a -> WrappedMonad m a forall (m :: * -> *) a. m a -> WrappedMonad m a WrapMonad (m a -> WrappedMonad m a) -> (a -> m a) -> a -> WrappedMonad m a forall b c a. (b -> c) -> (a -> b) -> a -> c . a -> m a forall a. a -> m a forall (f :: * -> *) a. Applicative f => a -> f a pure WrapMonad m (a -> b) f <*> :: forall a b. WrappedMonad m (a -> b) -> WrappedMonad m a -> WrappedMonad m b <*> WrapMonad m a v =m b -> WrappedMonad m b forall (m :: * -> *) a. m a -> WrappedMonad m a WrapMonad (m (a -> b) f m (a -> b) -> m a -> m b forall (m :: * -> *) a b. Monad m => m (a -> b) -> m a -> m b `ap` m a v )liftA2 :: forall a b c. (a -> b -> c) -> WrappedMonad m a -> WrappedMonad m b -> WrappedMonad m c liftA2 a -> b -> c f (WrapMonad m a x )(WrapMonad m b y )=m c -> WrappedMonad m c forall (m :: * -> *) a. m a -> WrappedMonad m a WrapMonad ((a -> b -> c) -> m a -> m b -> m c forall (m :: * -> *) a1 a2 r. Monad m => (a1 -> a2 -> r) -> m a1 -> m a2 -> m r liftM2 a -> b -> c f m a x m b y )-- | @since 2.01instanceMonadPlus m =>Alternative (WrappedMonad m )whereempty :: forall a. WrappedMonad m a empty =m a -> WrappedMonad m a forall (m :: * -> *) a. m a -> WrappedMonad m a WrapMonad m a forall a. m a forall (m :: * -> *) a. MonadPlus m => m a mzero WrapMonad m a u <|> :: forall a. WrappedMonad m a -> WrappedMonad m a -> WrappedMonad m a <|> WrapMonad m a v =m a -> WrappedMonad m a forall (m :: * -> *) a. m a -> WrappedMonad m a WrapMonad (m a u m a -> m a -> m a forall a. m a -> m a -> m a forall (m :: * -> *) a. MonadPlus m => m a -> m a -> m a `mplus` m a v )newtypeWrappedArrow a b c =WrapArrow {forall (a :: * -> * -> *) b c. WrappedArrow a b c -> a b c unwrapArrow ::a b c }deriving((forall x. WrappedArrow a b c -> Rep (WrappedArrow a b c) x) -> (forall x. Rep (WrappedArrow a b c) x -> WrappedArrow a b c) -> Generic (WrappedArrow a b c) forall x. Rep (WrappedArrow a b c) x -> WrappedArrow a b c forall x. WrappedArrow a b c -> Rep (WrappedArrow a b c) x forall a. (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a forall (a :: * -> * -> *) b c x. Rep (WrappedArrow a b c) x -> WrappedArrow a b c forall (a :: * -> * -> *) b c x. WrappedArrow a b c -> Rep (WrappedArrow a b c) x $cfrom :: forall (a :: * -> * -> *) b c x. WrappedArrow a b c -> Rep (WrappedArrow a b c) x from :: forall x. WrappedArrow a b c -> Rep (WrappedArrow a b c) x $cto :: forall (a :: * -> * -> *) b c x. Rep (WrappedArrow a b c) x -> WrappedArrow a b c to :: forall x. Rep (WrappedArrow a b c) x -> WrappedArrow a b c Generic -- ^ @since 4.7.0.0,(forall a. WrappedArrow a b a -> Rep1 (WrappedArrow a b) a) -> (forall a. Rep1 (WrappedArrow a b) a -> WrappedArrow a b a) -> Generic1 (WrappedArrow a b) forall a. Rep1 (WrappedArrow a b) a -> WrappedArrow a b a forall a. WrappedArrow a b a -> Rep1 (WrappedArrow a b) a forall k (f :: k -> *). (forall (a :: k). f a -> Rep1 f a) -> (forall (a :: k). Rep1 f a -> f a) -> Generic1 f forall (a :: * -> * -> *) b a. Rep1 (WrappedArrow a b) a -> WrappedArrow a b a forall (a :: * -> * -> *) b a. WrappedArrow a b a -> Rep1 (WrappedArrow a b) a $cfrom1 :: forall (a :: * -> * -> *) b a. WrappedArrow a b a -> Rep1 (WrappedArrow a b) a from1 :: forall a. WrappedArrow a b a -> Rep1 (WrappedArrow a b) a $cto1 :: forall (a :: * -> * -> *) b a. Rep1 (WrappedArrow a b) a -> WrappedArrow a b a to1 :: forall a. Rep1 (WrappedArrow a b) a -> WrappedArrow a b a Generic1 -- ^ @since 4.7.0.0)-- | @since 2.01instanceArrow a =>Functor (WrappedArrow a b )wherefmap :: forall a b. (a -> b) -> WrappedArrow a b a -> WrappedArrow a b b fmap a -> b f (WrapArrow a b a a )=a b b -> WrappedArrow a b b forall (a :: * -> * -> *) b c. a b c -> WrappedArrow a b c WrapArrow (a b a a a b a -> a a b -> a b b forall {k} (cat :: k -> k -> *) (a :: k) (b :: k) (c :: k). Category cat => cat a b -> cat b c -> cat a c >>> (a -> b) -> a a b forall b c. (b -> c) -> a b c forall (a :: * -> * -> *) b c. Arrow a => (b -> c) -> a b c arr a -> b f )-- | @since 2.01instanceArrow a =>Applicative (WrappedArrow a b )wherepure :: forall a. a -> WrappedArrow a b a pure a x =a b a -> WrappedArrow a b a forall (a :: * -> * -> *) b c. a b c -> WrappedArrow a b c WrapArrow ((b -> a) -> a b a forall b c. (b -> c) -> a b c forall (a :: * -> * -> *) b c. Arrow a => (b -> c) -> a b c arr (a -> b -> a forall a b. a -> b -> a const a x ))liftA2 :: forall a b c. (a -> b -> c) -> WrappedArrow a b a -> WrappedArrow a b b -> WrappedArrow a b c liftA2 a -> b -> c f (WrapArrow a b a u )(WrapArrow a b b v )=a b c -> WrappedArrow a b c forall (a :: * -> * -> *) b c. a b c -> WrappedArrow a b c WrapArrow (a b a u a b a -> a b b -> a b (a, b) forall b c c'. a b c -> a b c' -> a b (c, c') forall (a :: * -> * -> *) b c c'. Arrow a => a b c -> a b c' -> a b (c, c') &&& a b b v a b (a, b) -> a (a, b) c -> a b c forall {k} (cat :: k -> k -> *) (a :: k) (b :: k) (c :: k). Category cat => cat a b -> cat b c -> cat a c >>> ((a, b) -> c) -> a (a, b) c forall b c. (b -> c) -> a b c forall (a :: * -> * -> *) b c. Arrow a => (b -> c) -> a b c arr ((a -> b -> c) -> (a, b) -> c forall a b c. (a -> b -> c) -> (a, b) -> c uncurry a -> b -> c f ))-- | @since 2.01instance(ArrowZero a ,ArrowPlus a )=>Alternative (WrappedArrow a b )whereempty :: forall a. WrappedArrow a b a empty =a b a -> WrappedArrow a b a forall (a :: * -> * -> *) b c. a b c -> WrappedArrow a b c WrapArrow a b a forall b c. a b c forall (a :: * -> * -> *) b c. ArrowZero a => a b c zeroArrow WrapArrow a b a u <|> :: forall a. WrappedArrow a b a -> WrappedArrow a b a -> WrappedArrow a b a <|> WrapArrow a b a v =a b a -> WrappedArrow a b a forall (a :: * -> * -> *) b c. a b c -> WrappedArrow a b c WrapArrow (a b a u a b a -> a b a -> a b a forall b c. a b c -> a b c -> a b c forall (a :: * -> * -> *) b c. ArrowPlus a => a b c -> a b c -> a b c <+> a b a v )-- | Lists, but with an 'Applicative' functor based on zipping.newtypeZipList a =ZipList {forall a. ZipList a -> [a] getZipList ::[a ]}deriving(Int -> ZipList a -> ShowS [ZipList a] -> ShowS ZipList a -> String (Int -> ZipList a -> ShowS) -> (ZipList a -> String) -> ([ZipList a] -> ShowS) -> Show (ZipList a) forall a. Show a => Int -> ZipList a -> ShowS forall a. Show a => [ZipList a] -> ShowS forall a. Show a => ZipList a -> String forall a. (Int -> a -> ShowS) -> (a -> String) -> ([a] -> ShowS) -> Show a $cshowsPrec :: forall a. Show a => Int -> ZipList a -> ShowS showsPrec :: Int -> ZipList a -> ShowS $cshow :: forall a. Show a => ZipList a -> String show :: ZipList a -> String $cshowList :: forall a. Show a => [ZipList a] -> ShowS showList :: [ZipList a] -> ShowS Show -- ^ @since 4.7.0.0,ZipList a -> ZipList a -> Bool (ZipList a -> ZipList a -> Bool) -> (ZipList a -> ZipList a -> Bool) -> Eq (ZipList a) forall a. Eq a => ZipList a -> ZipList a -> Bool forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a $c== :: forall a. Eq a => ZipList a -> ZipList a -> Bool == :: ZipList a -> ZipList a -> Bool $c/= :: forall a. Eq a => ZipList a -> ZipList a -> Bool /= :: ZipList a -> ZipList a -> Bool Eq -- ^ @since 4.7.0.0,Eq (ZipList a) Eq (ZipList a) => (ZipList a -> ZipList a -> Ordering) -> (ZipList a -> ZipList a -> Bool) -> (ZipList a -> ZipList a -> Bool) -> (ZipList a -> ZipList a -> Bool) -> (ZipList a -> ZipList a -> Bool) -> (ZipList a -> ZipList a -> ZipList a) -> (ZipList a -> ZipList a -> ZipList a) -> Ord (ZipList a) ZipList a -> ZipList a -> Bool ZipList a -> ZipList a -> Ordering ZipList a -> ZipList a -> ZipList a forall a. Eq a => (a -> a -> Ordering) -> (a -> a -> Bool) -> (a -> a -> Bool) -> (a -> a -> Bool) -> (a -> a -> Bool) -> (a -> a -> a) -> (a -> a -> a) -> Ord a forall a. Ord a => Eq (ZipList a) forall a. Ord a => ZipList a -> ZipList a -> Bool forall a. Ord a => ZipList a -> ZipList a -> Ordering forall a. Ord a => ZipList a -> ZipList a -> ZipList a $ccompare :: forall a. Ord a => ZipList a -> ZipList a -> Ordering compare :: ZipList a -> ZipList a -> Ordering $c< :: forall a. Ord a => ZipList a -> ZipList a -> Bool < :: ZipList a -> ZipList a -> Bool $c<= :: forall a. Ord a => ZipList a -> ZipList a -> Bool <= :: ZipList a -> ZipList a -> Bool $c> :: forall a. Ord a => ZipList a -> ZipList a -> Bool > :: ZipList a -> ZipList a -> Bool $c>= :: forall a. Ord a => ZipList a -> ZipList a -> Bool >= :: ZipList a -> ZipList a -> Bool $cmax :: forall a. Ord a => ZipList a -> ZipList a -> ZipList a max :: ZipList a -> ZipList a -> ZipList a $cmin :: forall a. Ord a => ZipList a -> ZipList a -> ZipList a min :: ZipList a -> ZipList a -> ZipList a Ord -- ^ @since 4.7.0.0,ReadPrec [ZipList a] ReadPrec (ZipList a) Int -> ReadS (ZipList a) ReadS [ZipList a] (Int -> ReadS (ZipList a)) -> ReadS [ZipList a] -> ReadPrec (ZipList a) -> ReadPrec [ZipList a] -> Read (ZipList a) forall a. Read a => ReadPrec [ZipList a] forall a. Read a => ReadPrec (ZipList a) forall a. Read a => Int -> ReadS (ZipList a) forall a. Read a => ReadS [ZipList a] forall a. (Int -> ReadS a) -> ReadS [a] -> ReadPrec a -> ReadPrec [a] -> Read a $creadsPrec :: forall a. Read a => Int -> ReadS (ZipList a) readsPrec :: Int -> ReadS (ZipList a) $creadList :: forall a. Read a => ReadS [ZipList a] readList :: ReadS [ZipList a] $creadPrec :: forall a. Read a => ReadPrec (ZipList a) readPrec :: ReadPrec (ZipList a) $creadListPrec :: forall a. Read a => ReadPrec [ZipList a] readListPrec :: ReadPrec [ZipList a] Read -- ^ @since 4.7.0.0,(forall a b. (a -> b) -> ZipList a -> ZipList b) -> (forall a b. a -> ZipList b -> ZipList a) -> Functor ZipList forall a b. a -> ZipList b -> ZipList a forall a b. (a -> b) -> ZipList a -> ZipList b forall (f :: * -> *). (forall a b. (a -> b) -> f a -> f b) -> (forall a b. a -> f b -> f a) -> Functor f $cfmap :: forall a b. (a -> b) -> ZipList a -> ZipList b fmap :: forall a b. (a -> b) -> ZipList a -> ZipList b $c<$ :: forall a b. a -> ZipList b -> ZipList a <$ :: forall a b. a -> ZipList b -> ZipList a Functor -- ^ @since 2.01,(forall m. Monoid m => ZipList m -> m) -> (forall m a. Monoid m => (a -> m) -> ZipList a -> m) -> (forall m a. Monoid m => (a -> m) -> ZipList a -> m) -> (forall a b. (a -> b -> b) -> b -> ZipList a -> b) -> (forall a b. (a -> b -> b) -> b -> ZipList a -> b) -> (forall b a. (b -> a -> b) -> b -> ZipList a -> b) -> (forall b a. (b -> a -> b) -> b -> ZipList a -> b) -> (forall a. (a -> a -> a) -> ZipList a -> a) -> (forall a. (a -> a -> a) -> ZipList a -> a) -> (forall a. ZipList a -> [a]) -> (forall a. ZipList a -> Bool) -> (forall a. ZipList a -> Int) -> (forall a. Eq a => a -> ZipList a -> Bool) -> (forall a. Ord a => ZipList a -> a) -> (forall a. Ord a => ZipList a -> a) -> (forall a. Num a => ZipList a -> a) -> (forall a. Num a => ZipList a -> a) -> Foldable ZipList forall a. Eq a => a -> ZipList a -> Bool forall a. Num a => ZipList a -> a forall a. Ord a => ZipList a -> a forall m. Monoid m => ZipList m -> m forall a. ZipList a -> Bool forall a. ZipList a -> Int forall a. ZipList a -> [a] forall a. (a -> a -> a) -> ZipList a -> a forall m a. Monoid m => (a -> m) -> ZipList a -> m forall b a. (b -> a -> b) -> b -> ZipList a -> b forall a b. (a -> b -> b) -> b -> ZipList a -> b forall (t :: * -> *). (forall m. Monoid m => t m -> m) -> (forall m a. Monoid m => (a -> m) -> t a -> m) -> (forall m a. Monoid m => (a -> m) -> t a -> m) -> (forall a b. (a -> b -> b) -> b -> t a -> b) -> (forall a b. (a -> b -> b) -> b -> t a -> b) -> (forall b a. (b -> a -> b) -> b -> t a -> b) -> (forall b a. (b -> a -> b) -> b -> t a -> b) -> (forall a. (a -> a -> a) -> t a -> a) -> (forall a. (a -> a -> a) -> t a -> a) -> (forall a. t a -> [a]) -> (forall a. t a -> Bool) -> (forall a. t a -> Int) -> (forall a. Eq a => a -> t a -> Bool) -> (forall a. Ord a => t a -> a) -> (forall a. Ord a => t a -> a) -> (forall a. Num a => t a -> a) -> (forall a. Num a => t a -> a) -> Foldable t $cfold :: forall m. Monoid m => ZipList m -> m fold :: forall m. Monoid m => ZipList m -> m $cfoldMap :: forall m a. Monoid m => (a -> m) -> ZipList a -> m foldMap :: forall m a. Monoid m => (a -> m) -> ZipList a -> m $cfoldMap' :: forall m a. Monoid m => (a -> m) -> ZipList a -> m foldMap' :: forall m a. Monoid m => (a -> m) -> ZipList a -> m $cfoldr :: forall a b. (a -> b -> b) -> b -> ZipList a -> b foldr :: forall a b. (a -> b -> b) -> b -> ZipList a -> b $cfoldr' :: forall a b. (a -> b -> b) -> b -> ZipList a -> b foldr' :: forall a b. (a -> b -> b) -> b -> ZipList a -> b $cfoldl :: forall b a. (b -> a -> b) -> b -> ZipList a -> b foldl :: forall b a. (b -> a -> b) -> b -> ZipList a -> b $cfoldl' :: forall b a. (b -> a -> b) -> b -> ZipList a -> b foldl' :: forall b a. (b -> a -> b) -> b -> ZipList a -> b $cfoldr1 :: forall a. (a -> a -> a) -> ZipList a -> a foldr1 :: forall a. (a -> a -> a) -> ZipList a -> a $cfoldl1 :: forall a. (a -> a -> a) -> ZipList a -> a foldl1 :: forall a. (a -> a -> a) -> ZipList a -> a $ctoList :: forall a. ZipList a -> [a] toList :: forall a. ZipList a -> [a] $cnull :: forall a. ZipList a -> Bool null :: forall a. ZipList a -> Bool $clength :: forall a. ZipList a -> Int length :: forall a. ZipList a -> Int $celem :: forall a. Eq a => a -> ZipList a -> Bool elem :: forall a. Eq a => a -> ZipList a -> Bool $cmaximum :: forall a. Ord a => ZipList a -> a maximum :: forall a. Ord a => ZipList a -> a $cminimum :: forall a. Ord a => ZipList a -> a minimum :: forall a. Ord a => ZipList a -> a $csum :: forall a. Num a => ZipList a -> a sum :: forall a. Num a => ZipList a -> a $cproduct :: forall a. Num a => ZipList a -> a product :: forall a. Num a => ZipList a -> a Foldable -- ^ @since 4.9.0.0,(forall x. ZipList a -> Rep (ZipList a) x) -> (forall x. Rep (ZipList a) x -> ZipList a) -> Generic (ZipList a) forall x. Rep (ZipList a) x -> ZipList a forall x. ZipList a -> Rep (ZipList a) x forall a. (forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a forall a x. Rep (ZipList a) x -> ZipList a forall a x. ZipList a -> Rep (ZipList a) x $cfrom :: forall a x. ZipList a -> Rep (ZipList a) x from :: forall x. ZipList a -> Rep (ZipList a) x $cto :: forall a x. Rep (ZipList a) x -> ZipList a to :: forall x. Rep (ZipList a) x -> ZipList a Generic -- ^ @since 4.7.0.0,(forall a. ZipList a -> Rep1 ZipList a) -> (forall a. Rep1 ZipList a -> ZipList a) -> Generic1 ZipList forall a. Rep1 ZipList a -> ZipList a forall a. ZipList a -> Rep1 ZipList a forall k (f :: k -> *). (forall (a :: k). f a -> Rep1 f a) -> (forall (a :: k). Rep1 f a -> f a) -> Generic1 f $cfrom1 :: forall a. ZipList a -> Rep1 ZipList a from1 :: forall a. ZipList a -> Rep1 ZipList a $cto1 :: forall a. Rep1 ZipList a -> ZipList a to1 :: forall a. Rep1 ZipList a -> ZipList a Generic1 -- ^ @since 4.7.0.0)-- See Data.Traversable for Traversable instance due to import loops-- |-- > f <$> 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 2.01instanceApplicative ZipList wherepure :: forall a. a -> ZipList a pure a x =[a] -> ZipList a forall a. [a] -> ZipList a ZipList (a -> [a] forall a. a -> [a] repeat a x )liftA2 :: forall a b c. (a -> b -> c) -> ZipList a -> ZipList b -> ZipList c liftA2 a -> b -> c f (ZipList [a] xs )(ZipList [b] ys )=[c] -> ZipList c forall a. [a] -> ZipList a ZipList ((a -> b -> c) -> [a] -> [b] -> [c] forall a b c. (a -> b -> c) -> [a] -> [b] -> [c] zipWith a -> b -> c f [a] xs [b] ys )-- | @since 4.11.0.0instanceAlternative ZipList whereempty :: forall a. ZipList a empty =[a] -> ZipList a forall a. [a] -> ZipList a ZipList []ZipList [a] xs0 <|> :: forall a. ZipList a -> ZipList a -> ZipList a <|> ZipList [a] ys0 =[a] -> ZipList a forall a. [a] -> ZipList a ZipList ([a] -> ZipList a) -> [a] -> ZipList a forall a b. (a -> b) -> a -> b $ [a] -> [a] -> [a] forall {a}. [a] -> [a] -> [a] go [a] xs0 [a] ys0 wherego :: [a] -> [a] -> [a] go (a x : [a] xs )(a _: [a] ys )=a x a -> [a] -> [a] forall a. a -> [a] -> [a] : [a] -> [a] -> [a] go [a] xs [a] ys go [][a] ys =[a] ys go [a] xs [a] _=[a] xs -- extra functions-- | One or none.---- It is useful for modelling any computation that is allowed to fail.---- ==== __Examples__---- 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 42optional ::Alternative f =>f a ->f (Maybe a )optional :: forall (f :: * -> *) a. Alternative f => f a -> f (Maybe a) optional f a v =a -> Maybe a forall a. a -> Maybe a Just (a -> Maybe a) -> f a -> f (Maybe a) forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b <$> f a v f (Maybe a) -> f (Maybe a) -> f (Maybe a) forall a. f a -> f a -> f a forall (f :: * -> *) a. Alternative f => f a -> f a -> f a <|> Maybe a -> f (Maybe a) forall a. a -> f a forall (f :: * -> *) a. Applicative f => a -> f a pure Maybe a forall a. Maybe a Nothing