Hans.Lens

Lenses

type Lens s t a b = forall f. Functor f => (a -> f b) -> s -> f t

General lenses that allow for the type of the inner field to change.

type Lens' s a = Lens s s a a

Lenses that don't change type.

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

Getters

type Getting r s a = (a -> Const r a) -> s -> Const r s

type Getter s a = forall r. Getting r s a

view :: Getting a s a -> s -> a

to :: (s -> a) -> Getting r s a

Setters

type ASetter s t a b = (a -> Id b) -> s -> Id t

type ASetter' s a = ASetter s s a a

set :: Lens s t a b -> b -> s -> t

over :: ASetter s t a b -> (a -> b) -> s -> t

modify :: Lens s t a b -> (a -> (b, r)) -> s -> (t, r)

Utility Lenses

bit :: Bits a => Int -> Lens' a Bool

byte :: (Integral a, Bits a) => Int -> Lens' a Word8