Welcome to the lens wiki!

You probably want to start with some Examples, the Overview or a cheatsheet of many of the Operators.

If you are interested in the design behind these lenses, you may want to also dig into their Derivation.

Please help us by expanding the FAQ.

A quick overview of the key operations of the core of the hierarchy of lens types can be seen below.

Contact Information

Contributions and bug reports are welcome! Please, feel free to update the content, as this is much more useful as a living document than as something that gets updated when I remember to do so.

I can be contacted through github or on the #haskell or #haskell-lens IRC channels on irc.freenode.net.

-Edward Kmett