Getting Started

$ ghci GHCi, version 7.4.2: http://www.haskell.org/ghc/ :? for help Loading package ghc-prim ... linking ... done. Loading package integer-gmp ... linking ... done. Loading package base ... linking ... done. and import Control.Lens. ghci> import Control.Lens Now, you can read from lenses ghci> ("hello","world")^._2 "world" and you can write to lenses. ghci> set _2 42 ("hello","world") ("hello",42)