Left package:lens-family-core

left :: (Applicative f, Traversable g) => AdapterLike f g (Either a r) (Either b r) a b
lens-family-core Lens.Family.Stock
left :: Prism (Either a r) (Either b r) a b
A prism on the Left element of an Either.
left_ :: Applicative f => LensLike f (Either a r) (Either b r) a b
lens-family-core Lens.Family.Stock
left_ :: Traversal (Either a r) (Either b r) a b
Traversal on the Left element of an Either. 
left_ = under left
data AlongsideLeft f b a
lens-family-core Lens.Family.Stock