Data.Lens.Barlow

class Barlow :: Symbol -> (Type -> Type -> Type) -> Type -> Type -> Type -> Type -> Constraintclass Barlow (string :: Symbol) p s t a b | string -> s t a b where

Members

• barlowImpl :: Proxy string -> Optic p s t a b

Instances

• (ParseSymbol string lenses, ConstructBarlow lenses p s t a b) => Barlow string p s t a b

barlow :: forall @string lenses p s t a b. ParseSymbol string lenses => ConstructBarlow lenses p s t a b => IsSymbol string => Optic p s t a b

Type-safe lens for zooming into a deeply nested record

sky = { zodiac: { virgo: { alpha: "Spica" } } }
view (barlow @"zodiac.virgo.alpha") sky
-- Spica 
over (barlow @"zodiac.virgo.alpha") toUpper sky
-- { zodiac: { virgo: { alpha: "SPICA" } } }

key :: forall k. Proxy k

Just an alias for Proxy to make selection a bit nicer