lens-family-1.2.2: Lens Families

Safe HaskellSafe
LanguageHaskell98

Lens.Family2.Stock

Contents

Description

This module contains lenses and traversals for common structures in Haskell. It also contains the combinators for lenses and traversals.

Synopsis

Lens Combinators

choosing :: Functor f => LensLike f a a' c c' -> LensLike f b b' c c' -> LensLike f (Either a b) (Either a' b') c c' #

choosing :: Lens a a' c c' -> Lens b b' c c' -> Lens (Either a b) (Either a' b') c c'
choosing :: Traversal a a' c c' -> Traversal b b' c c' -> Traversal (Either a b) (Either a' b') c c'
choosing :: Getter a a' c c' -> Getter b b' c c' -> Getter (Either a b) (Either a' b') c c'
choosing :: Fold a a' c c' -> Fold b b' c c' -> Fold (Either a b) (Either a' b') c c'
choosing :: Setter a a' c c' -> Setter b b' c c' -> Setter (Either a b) (Either a' b') c c'

Given two lens/traversal/getter/fold/setter families with the same substructure, make a new lens/traversal/getter/fold/setter on Either.

alongside :: Functor f => LensLike (AlongsideLeft f b2') a1 a1' b1 b1' -> LensLike (AlongsideRight f a1') a2 a2' b2 b2' -> LensLike f (a1, a2) (a1', a2') (b1, b2) (b1', b2') #

alongside :: Lens a1 a1' b1 b1' -> Lens a2 a2' b2 b2' -> Lens (a1, a2) (a1', a2') (b1, b2) (b1', b2')
alongside :: Getter a1 a1' b1 b1' -> Getter a2 a2' b2 b2' -> Getter (a1, a2) (a1', a2') (b1, b2) (b1', b2')

Given two lens/getter families, make a new lens/getter on their product.

beside :: Applicative f => LensLike f a a' c c' -> LensLike f b b' c c' -> LensLike f (a, b) (a', b') c c' #

beside :: Traversal a a' c c' -> Traversal b' b' c c' -> Traversal (a,b) (a',b') c c'
beside :: Fold a a' c c' -> Fold b' b' c c' -> Fold (a,b) (a',b') c c'
beside :: Setter a a' c c' -> Setter b' b' c c' -> Setter (a,b) (a',b') c c'

Given two traversals/folds/setters referencing a type c, create a traversal/fold/setter on the pair referencing c.

Stock Lenses

_1 :: Lens (a, b) (a', b) a a' Source #

Lens on the first element of a pair.

_2 :: Lens (a, b) (a, b') b b' Source #

Lens on the second element of a pair.

chosen :: Lens (Either a a) (Either b b) a b Source #

Lens on the Left or Right element of an (Either a a).

ix :: Eq k => k -> Lens' (k -> v) v Source #

Lens on a given point of a function.

at :: Ord k => k -> Lens' (Map k v) (Maybe v) Source #

Lens on a given point of a Map.

intAt :: Int -> Lens' (IntMap v) (Maybe v) Source #

Lens on a given point of a IntMap.

at' :: Ord k => k -> Lens' (Map k v) (Maybe v) Source #

Lens providing strict access to a given point of a Map.

intAt' :: Int -> Lens' (IntMap v) (Maybe v) Source #

Lens providing strict access to a given point of a IntMap.

contains :: Ord k => k -> Lens' (Set k) Bool Source #

Lens on a given point of a Set.

intContains :: Int -> Lens' IntSet Bool Source #

Lens on a given point of a IntSet.

Stock Traversals

both :: Traversal (a, a) (b, b) a b Source #

Traversals on both elements of a pair (a,a).

_Left :: Traversal (Either a b) (Either a' b) a a' Source #

Traversal on the Left element of an Either.

_Right :: Traversal (Either a b) (Either a b') b b' Source #

Traversal on the Right element of an Either.

_Just :: Traversal (Maybe a) (Maybe a') a a' Source #

Traversal on the Just element of a Maybe.

_Nothing :: Traversal' (Maybe a) () Source #

Traversal on the Nothing element of a Maybe.

ignored :: Traversal a a b b' Source #

The empty traveral on any type.

Stock SECs

mapped :: Functor f => Setter (f a) (f a') a a' Source #

An SEC referencing the parameter of a functor.

Types

data AlongsideLeft f b a :: (* -> *) -> * -> * -> * #

Instances

Functor f => Functor (AlongsideLeft f a) 

Methods

fmap :: (a -> b) -> AlongsideLeft f a a -> AlongsideLeft f a b #

(<$) :: a -> AlongsideLeft f a b -> AlongsideLeft f a a #

Phantom f => Phantom (AlongsideLeft f a) 

Methods

coerce :: AlongsideLeft f a a -> AlongsideLeft f a b

data AlongsideRight f a b :: (* -> *) -> * -> * -> * #

Instances

Functor f => Functor (AlongsideRight f a) 

Methods

fmap :: (a -> b) -> AlongsideRight f a a -> AlongsideRight f a b #

(<$) :: a -> AlongsideRight f a b -> AlongsideRight f a a #

Phantom f => Phantom (AlongsideRight f a) 

Methods

coerce :: AlongsideRight f a a -> AlongsideRight f a b

Re-exports

type Lens a a' b b' = forall f. Functor f => LensLike f a a' b b' Source #

type Lens' a b = forall f. Functor f => LensLike' f a b Source #

type Traversal a a' b b' = forall f. Applicative f => LensLike f a a' b b' Source #

type Traversal' a b = forall f. Applicative f => LensLike' f a b Source #

type Setter a a' b b' = forall f. Identical f => LensLike f a a' b b' Source #

type LensLike f a a' b b' = (b -> f b') -> a -> f a' #

type LensLike' f a b = (b -> f b) -> a -> f a #

class Functor f => Applicative f #

A functor with application, providing operations to

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

A minimal complete definition must include implementations of these functions satisfying the following laws:

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:

As a consequence of these laws, the Functor instance for f will satisfy

If f is also a Monad, it should satisfy

(which implies that pure and <*> satisfy the applicative functor laws).

Minimal complete definition

pure, (<*>)

Instances

Applicative [] 

Methods

pure :: a -> [a] #

(<*>) :: [a -> b] -> [a] -> [b] #

(*>) :: [a] -> [b] -> [b] #

(<*) :: [a] -> [b] -> [a] #

Applicative Maybe 

Methods

pure :: a -> Maybe a #

(<*>) :: Maybe (a -> b) -> Maybe a -> Maybe b #

(*>) :: Maybe a -> Maybe b -> Maybe b #

(<*) :: Maybe a -> Maybe b -> Maybe a #

Applicative IO 

Methods

pure :: a -> IO a #

(<*>) :: IO (a -> b) -> IO a -> IO b #

(*>) :: IO a -> IO b -> IO b #

(<*) :: IO a -> IO b -> IO a #

Applicative U1 

Methods

pure :: a -> U1 a #

(<*>) :: U1 (a -> b) -> U1 a -> U1 b #

(*>) :: U1 a -> U1 b -> U1 b #

(<*) :: U1 a -> U1 b -> U1 a #

Applicative Par1 

Methods

pure :: a -> Par1 a #

(<*>) :: Par1 (a -> b) -> Par1 a -> Par1 b #

(*>) :: Par1 a -> Par1 b -> Par1 b #

(<*) :: Par1 a -> Par1 b -> Par1 a #

Applicative Identity 

Methods

pure :: a -> Identity a #

(<*>) :: Identity (a -> b) -> Identity a -> Identity b #

(*>) :: Identity a -> Identity b -> Identity b #

(<*) :: Identity a -> Identity b -> Identity a #

Applicative ZipList 

Methods

pure :: a -> ZipList a #

(<*>) :: ZipList (a -> b) -> ZipList a -> ZipList b #

(*>) :: ZipList a -> ZipList b -> ZipList b #

(<*) :: ZipList a -> ZipList b -> ZipList a #

Applicative Dual 

Methods

pure :: a -> Dual a #

(<*>) :: Dual (a -> b) -> Dual a -> Dual b #

(*>) :: Dual a -> Dual b -> Dual b #

(<*) :: Dual a -> Dual b -> Dual a #

Applicative Sum 

Methods

pure :: a -> Sum a #

(<*>) :: Sum (a -> b) -> Sum a -> Sum b #

(*>) :: Sum a -> Sum b -> Sum b #

(<*) :: Sum a -> Sum b -> Sum a #

Applicative Product 

Methods

pure :: a -> Product a #

(<*>) :: Product (a -> b) -> Product a -> Product b #

(*>) :: Product a -> Product b -> Product b #

(<*) :: Product a -> Product b -> Product a #

Applicative First 

Methods

pure :: a -> First a #

(<*>) :: First (a -> b) -> First a -> First b #

(*>) :: First a -> First b -> First b #

(<*) :: First a -> First b -> First a #

Applicative Last 

Methods

pure :: a -> Last a #

(<*>) :: Last (a -> b) -> Last a -> Last b #

(*>) :: Last a -> Last b -> Last b #

(<*) :: Last a -> Last b -> Last a #

Applicative ((->) a) 

Methods

pure :: a -> a -> a #

(<*>) :: (a -> a -> b) -> (a -> a) -> a -> b #

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

(<*) :: (a -> a) -> (a -> b) -> a -> a #

Applicative (Either e) 

Methods

pure :: a -> Either e a #

(<*>) :: Either e (a -> b) -> Either e a -> Either e b #

(*>) :: Either e a -> Either e b -> Either e b #

(<*) :: Either e a -> Either e b -> Either e a #

Applicative f => Applicative (Rec1 f) 

Methods

pure :: a -> Rec1 f a #

(<*>) :: Rec1 f (a -> b) -> Rec1 f a -> Rec1 f b #

(*>) :: Rec1 f a -> Rec1 f b -> Rec1 f b #

(<*) :: Rec1 f a -> Rec1 f b -> Rec1 f a #

Monoid a => Applicative ((,) a) 

Methods

pure :: a -> (a, a) #

(<*>) :: (a, a -> b) -> (a, a) -> (a, b) #

(*>) :: (a, a) -> (a, b) -> (a, b) #

(<*) :: (a, a) -> (a, b) -> (a, a) #

Monad m => Applicative (WrappedMonad m) 

Methods

pure :: a -> WrappedMonad m a #

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

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

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

Applicative (Proxy *) 

Methods

pure :: a -> Proxy * a #

(<*>) :: Proxy * (a -> b) -> Proxy * a -> Proxy * b #

(*>) :: Proxy * a -> Proxy * b -> Proxy * b #

(<*) :: Proxy * a -> Proxy * b -> Proxy * a #

Applicative m => Applicative (ListT m) 

Methods

pure :: a -> ListT m a #

(<*>) :: ListT m (a -> b) -> ListT m a -> ListT m b #

(*>) :: ListT m a -> ListT m b -> ListT m b #

(<*) :: ListT m a -> ListT m b -> ListT m a #

(Functor m, Monad m) => Applicative (MaybeT m) 

Methods

pure :: a -> MaybeT m a #

(<*>) :: MaybeT m (a -> b) -> MaybeT m a -> MaybeT m b #

(*>) :: MaybeT m a -> MaybeT m b -> MaybeT m b #

(<*) :: MaybeT m a -> MaybeT m b -> MaybeT m a #

(Applicative f, Applicative g) => Applicative ((:*:) f g) 

Methods

pure :: a -> (f :*: g) a #

(<*>) :: (f :*: g) (a -> b) -> (f :*: g) a -> (f :*: g) b #

(*>) :: (f :*: g) a -> (f :*: g) b -> (f :*: g) b #

(<*) :: (f :*: g) a -> (f :*: g) b -> (f :*: g) a #

(Applicative f, Applicative g) => Applicative ((:.:) f g) 

Methods

pure :: a -> (f :.: g) a #

(<*>) :: (f :.: g) (a -> b) -> (f :.: g) a -> (f :.: g) b #

(*>) :: (f :.: g) a -> (f :.: g) b -> (f :.: g) b #

(<*) :: (f :.: g) a -> (f :.: g) b -> (f :.: g) a #

Arrow a => Applicative (WrappedArrow a b) 

Methods

pure :: a -> WrappedArrow a b a #

(<*>) :: WrappedArrow a b (a -> b) -> WrappedArrow a b a -> WrappedArrow a b b #

(*>) :: WrappedArrow a b a -> WrappedArrow a b b -> WrappedArrow a b b #

(<*) :: WrappedArrow a b a -> WrappedArrow a b b -> WrappedArrow a b a #

Applicative f => Applicative (Alt * f) 

Methods

pure :: a -> Alt * f a #

(<*>) :: Alt * f (a -> b) -> Alt * f a -> Alt * f b #

(*>) :: Alt * f a -> Alt * f b -> Alt * f b #

(<*) :: Alt * f a -> Alt * f b -> Alt * f a #

(Applicative f, Monad f) => Applicative (WhenMissing f x)

Equivalent to ReaderT k (ReaderT x (MaybeT f)).

Methods

pure :: a -> WhenMissing f x a #

(<*>) :: WhenMissing f x (a -> b) -> WhenMissing f x a -> WhenMissing f x b #

(*>) :: WhenMissing f x a -> WhenMissing f x b -> WhenMissing f x b #

(<*) :: WhenMissing f x a -> WhenMissing f x b -> WhenMissing f x a #

(Monoid c, Monad m) => Applicative (Zooming m c) 

Methods

pure :: a -> Zooming m c a #

(<*>) :: Zooming m c (a -> b) -> Zooming m c a -> Zooming m c b #

(*>) :: Zooming m c a -> Zooming m c b -> Zooming m c b #

(<*) :: Zooming m c a -> Zooming m c b -> Zooming m c a #

Monoid a => Applicative (Constant * a) 

Methods

pure :: a -> Constant * a a #

(<*>) :: Constant * a (a -> b) -> Constant * a a -> Constant * a b #

(*>) :: Constant * a a -> Constant * a b -> Constant * a b #

(<*) :: Constant * a a -> Constant * a b -> Constant * a a #

(Functor m, Monad m) => Applicative (StateT s m) 

Methods

pure :: a -> StateT s m a #

(<*>) :: StateT s m (a -> b) -> StateT s m a -> StateT s m b #

(*>) :: StateT s m a -> StateT s m b -> StateT s m b #

(<*) :: StateT s m a -> StateT s m b -> StateT s m a #

(Functor m, Monad m) => Applicative (StateT s m) 

Methods

pure :: a -> StateT s m a #

(<*>) :: StateT s m (a -> b) -> StateT s m a -> StateT s m b #

(*>) :: StateT s m a -> StateT s m b -> StateT s m b #

(<*) :: StateT s m a -> StateT s m b -> StateT s m a #

Applicative f => Applicative (Backwards * f)

Apply f-actions in the reverse order.

Methods

pure :: a -> Backwards * f a #

(<*>) :: Backwards * f (a -> b) -> Backwards * f a -> Backwards * f b #

(*>) :: Backwards * f a -> Backwards * f b -> Backwards * f b #

(<*) :: Backwards * f a -> Backwards * f b -> Backwards * f a #

(Functor m, Monad m) => Applicative (ErrorT e m) 

Methods

pure :: a -> ErrorT e m a #

(<*>) :: ErrorT e m (a -> b) -> ErrorT e m a -> ErrorT e m b #

(*>) :: ErrorT e m a -> ErrorT e m b -> ErrorT e m b #

(<*) :: ErrorT e m a -> ErrorT e m b -> ErrorT e m a #

(Functor m, Monad m) => Applicative (ExceptT e m) 

Methods

pure :: a -> ExceptT e m a #

(<*>) :: ExceptT e m (a -> b) -> ExceptT e m a -> ExceptT e m b #

(*>) :: ExceptT e m a -> ExceptT e m b -> ExceptT e m b #

(<*) :: ExceptT e m a -> ExceptT e m b -> ExceptT e m a #

(Monoid w, Applicative m) => Applicative (WriterT w m) 

Methods

pure :: a -> WriterT w m a #

(<*>) :: WriterT w m (a -> b) -> WriterT w m a -> WriterT w m b #

(*>) :: WriterT w m a -> WriterT w m b -> WriterT w m b #

(<*) :: WriterT w m a -> WriterT w m b -> WriterT w m a #

(Monoid w, Applicative m) => Applicative (WriterT w m) 

Methods

pure :: a -> WriterT w m a #

(<*>) :: WriterT w m (a -> b) -> WriterT w m a -> WriterT w m b #

(*>) :: WriterT w m a -> WriterT w m b -> WriterT w m b #

(<*) :: WriterT w m a -> WriterT w m b -> WriterT w m a #

Applicative m => Applicative (IdentityT * m) 

Methods

pure :: a -> IdentityT * m a #

(<*>) :: IdentityT * m (a -> b) -> IdentityT * m a -> IdentityT * m b #

(*>) :: IdentityT * m a -> IdentityT * m b -> IdentityT * m b #

(<*) :: IdentityT * m a -> IdentityT * m b -> IdentityT * m a #

Applicative f => Applicative (M1 i c f) 

Methods

pure :: a -> M1 i c f a #

(<*>) :: M1 i c f (a -> b) -> M1 i c f a -> M1 i c f b #

(*>) :: M1 i c f a -> M1 i c f b -> M1 i c f b #

(<*) :: M1 i c f a -> M1 i c f b -> M1 i c f a #

(Monad f, Applicative f) => Applicative (WhenMatched f x y)

Equivalent to ReaderT Key (ReaderT x (ReaderT y (MaybeT f)))

Methods

pure :: a -> WhenMatched f x y a #

(<*>) :: WhenMatched f x y (a -> b) -> WhenMatched f x y a -> WhenMatched f x y b #

(*>) :: WhenMatched f x y a -> WhenMatched f x y b -> WhenMatched f x y b #

(<*) :: WhenMatched f x y a -> WhenMatched f x y b -> WhenMatched f x y a #

(Applicative f, Monad f) => Applicative (WhenMissing f k x)

Equivalent to ReaderT k (ReaderT x (MaybeT f)) .

Methods

pure :: a -> WhenMissing f k x a #

(<*>) :: WhenMissing f k x (a -> b) -> WhenMissing f k x a -> WhenMissing f k x b #

(*>) :: WhenMissing f k x a -> WhenMissing f k x b -> WhenMissing f k x b #

(<*) :: WhenMissing f k x a -> WhenMissing f k x b -> WhenMissing f k x a #

Applicative (ContT k r m) 

Methods

pure :: a -> ContT k r m a #

(<*>) :: ContT k r m (a -> b) -> ContT k r m a -> ContT k r m b #

(*>) :: ContT k r m a -> ContT k r m b -> ContT k r m b #

(<*) :: ContT k r m a -> ContT k r m b -> ContT k r m a #

Applicative m => Applicative (ReaderT * r m) 

Methods

pure :: a -> ReaderT * r m a #

(<*>) :: ReaderT * r m (a -> b) -> ReaderT * r m a -> ReaderT * r m b #

(*>) :: ReaderT * r m a -> ReaderT * r m b -> ReaderT * r m b #

(<*) :: ReaderT * r m a -> ReaderT * r m b -> ReaderT * r m a #

(Monad f, Applicative f) => Applicative (WhenMatched f k x y)

Equivalent to ReaderT k (ReaderT x (ReaderT y (MaybeT f)))

Methods

pure :: a -> WhenMatched f k x y a #

(<*>) :: WhenMatched f k x y (a -> b) -> WhenMatched f k x y a -> WhenMatched f k x y b #

(*>) :: WhenMatched f k x y a -> WhenMatched f k x y b -> WhenMatched f k x y b #

(<*) :: WhenMatched f k x y a -> WhenMatched f k x y b -> WhenMatched f k x y a #

(Monoid w, Functor m, Monad m) => Applicative (RWST r w s m) 

Methods

pure :: a -> RWST r w s m a #

(<*>) :: RWST r w s m (a -> b) -> RWST r w s m a -> RWST r w s m b #

(*>) :: RWST r w s m a -> RWST r w s m b -> RWST r w s m b #

(<*) :: RWST r w s m a -> RWST r w s m b -> RWST r w s m a #

(Monoid w, Functor m, Monad m) => Applicative (RWST r w s m) 

Methods

pure :: a -> RWST r w s m a #

(<*>) :: RWST r w s m (a -> b) -> RWST r w s m a -> RWST r w s m b #

(*>) :: RWST r w s m a -> RWST r w s m b -> RWST r w s m b #

(<*) :: RWST r w s m a -> RWST r w s m b -> RWST r w s m a #

class Applicative f => Identical f #

Minimal complete definition

extract

Instances

Identical Identity 

Methods

extract :: Identity a -> a

Identical f => Identical (Backwards * f) 

Methods

extract :: Backwards * f a -> a

(Identical f, Identical g) => Identical (Compose * * f g) 

Methods

extract :: Compose * * f g a -> a