Control.Lens.Utils.Nested

Documentation

type NestedCtx a = (Index a ~ Index (IxValue a), IxValue a ~ IxValue (IxValue a))

type NestedAtCtx a = (NestedCtx a, At a, At (IxValue a))

type NestedIxedCtx a = (NestedCtx a, Ixed a, Ixed (IxValue a))

nestedAt :: (NestedAtCtx a, Mempty (IxValue a)) => NonEmpty (Index a) -> Lens' a (Maybe (IxValue a))

nestedDefAt :: NestedAtCtx a => IxValue a -> NonEmpty (Index a) -> Lens' a (Maybe (IxValue a))

nestedAt' :: (NestedAtCtx a, Mempty (IxValue a)) => NonEmpty (Index a) -> Lens' a (IxValue a)

nestedIx :: NestedIxedCtx a => NonEmpty (Index a) -> Traversal' a (IxValue a)

emptyMap :: Prism' (Map k a) ()

subMapAt :: (Ord p, Functor f) => p -> (Maybe a -> f (Maybe a)) -> Maybe (Map p a) -> f (Maybe (Map p a))

at' :: (Functor f, Ord p) => p -> (Maybe a -> f (Maybe a)) -> Maybe (Map p a) -> f (Maybe (Map p a))

unsafeLensedMapAt :: (Ord k, Default v) => k -> Lens' v a -> Lens' (Map k v) (Maybe a)

Warning! This function does not hold lens laws: deleting and re-adding a key destroys everything appart of a, so `set l (Just x) (set l Nothing s) /= set l (Just x) s`