Data.Lens.Barlow

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

Members

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

  Type-safe lens for zooming into a deeply nested record

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

Instances

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

key :: forall k. Proxy k

Just an alias for Proxy to make selection a bit nicer