This package comes "Batteries Included" with many useful lenses for the types
commonly used from the Haskell Platform, and with tools for automatically
generating lenses and isomorphisms for user-supplied data types.
The combinators in 'Control.Lens' provide a highly generic toolbox for
composing families of getters, folds, isomorphisms, traversals, setters and
lenses and their indexed variants.
An overview, with a large number of examples can be found in the README at
https://github.com/ekmett/lens#lens-lenses-folds-and-traversals.
