This package provides families of lenses, isomorphisms, folds, traversals, getters and setters.

Costate Comonad Coalgebra is equivalent of Java's member variable update technology for Haskell

@PLT_Borat on twitter

The FAQ, which provides links to a large number of different resources for learning about lenses and an overview of the derivation of these types can be found on the Lens Wiki along with a brief overview and some examples.

Documentation is available through github (for HEAD) or hackage for the current and preceding releases.

Recent Activity

Video from New York Haskell: Lenses, Folds and Traversals

Slides from this talk are also available.

© 2012 Edward Kmett.

Code licensed under BSD, documentation under CC BY 3.0.

Glyphicons Free licensed under CC BY 3.0.