Serokell.Util.Lens

Extra operators on Lens

Documentation

(%%=) :: Lens' s a -> State a b -> State s b infix 4

Similar to %= operator, but takes State action instead of (a -> a)

(%?=) :: Lens' s a -> ExceptT t (State a) b -> ExceptT t (State s) b infix 4

Like %%= but with possiblity of failure

zoom' :: MonadState s m => LensLike' (Zoomed (State s) a) s t -> StateT t Identity a -> m a

A zoom which works in arbitrary MonadState.

See https://github.com/ekmett/lens/issues/580. You might be surprised but actual zoom doesn't work in any MonadState, it only works in a handful of state monads and their combinations defined by Zoom.

magnify' :: MonadReader s m => LensLike' (Magnified (Reader s) a) s t -> ReaderT t Identity a -> m a

A magnify which works in arbitrary MonadReader.