Bookkeeper.Lens

Lenses

rlens :: (Settable field val' old new, Gettable field old val, Functor f) => Key field -> (val -> f val') -> Book' old -> f (Book' new)

Build a lens from a field

julian ^. rlens #age
   = 28

Symbols can also be used directly as lenses, so you probably don't need to use rlens:

julian ^. #age
   = 28

julian & #age .~ 29
   = Book {age = 29, name = "Julian K. Arni"}

Orphan instances

(Settable field valnew old new, Gettable field old val, Functor f, (~) * s2ft (Book' old -> f (Book' new))) => IsLabel field ((val -> f valnew) -> s2ft)

Methods

fromLabel :: (val -> f valnew) -> s2ft