Putlenses

This cabal package can be installed with:

$ cabal install putlenses

For a manual install, execute:

$ runhaskell Setup.lhs configure
$ runhaskell Setup.lhs build
$ runhaskell Setup.lhs install

You can now start playing with the example code that comes with the library, under Language.Pointless.Examples.Examples.
The easiest way is to create a new module that imports some library modules

module Test where

import Test.QuickCheck.Test
import Generics.Pointless.Lenses
import Generics.Pointless.Lenses.Examples.Examples

and interpret it

$ ghci Test.hs

We can now run some examples:
> exMssPut2
> exMssPut3