Data.Lens.Common

Documentation

newtype Lens a b

Constructors

Lens

Fields

runLens :: a -> Store b a

Instances

Category Lens

Semigroupoid Lens

Lens construction

lens :: (a -> b) -> (b -> a -> a) -> Lens a b

build a lens out of a getter and setter

iso :: (a -> b) -> (b -> a) -> Lens a b

build a lens out of an isomorphism

Functional API

(^$) :: Lens a b -> a -> b

(^$!) :: Lens a b -> a -> b

functional getter

(^.) :: a -> Lens a b -> b

(^!) :: a -> Lens a b -> b

functional getter, which acts like a field accessor

(^=) :: Lens a b -> b -> a -> a

(^!=) :: Lens a b -> b -> a -> a

functional setter

(^%=) :: Lens a b -> (b -> b) -> a -> a

(^!%=) :: Lens a b -> (b -> b) -> a -> a

functional modify

(^%%=) :: Functor f => Lens a b -> (b -> f b) -> a -> f a

functorial modify

Pseudo-imperatives

(^+=) :: Num b => Lens a b -> b -> a -> a

(^!+=) :: Num b => Lens a b -> b -> a -> a

(^-=) :: Num b => Lens a b -> b -> a -> a

(^!-=) :: Num b => Lens a b -> b -> a -> a

(^*=) :: Num b => Lens a b -> b -> a -> a

(^!*=) :: Num b => Lens a b -> b -> a -> a

(^/=) :: Fractional b => Lens a b -> b -> a -> a

(^!/=) :: Fractional b => Lens a b -> b -> a -> a

Stock lenses

fstLens :: Lens (a, b) a

sndLens :: Lens (a, b) b

mapLens :: Ord k => k -> Lens (Map k v) (Maybe v)

intMapLens :: Int -> Lens (IntMap v) (Maybe v)

setLens :: Ord k => k -> Lens (Set k) Bool

intSetLens :: Int -> Lens IntSet Bool