Install libghc-lens-doc by entering the following commands in the terminal:
sudo apt update sudo apt install libghc-lens-doc
Description:
Lenses, Folds and Traversals; documentation
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. . More information on the care and feeding of lenses, including a tutorial and motivation for their types can be found on the lens wiki (https://github.com/ekmett/lens/wiki). . This package contains the documentation files.
Homepage: http://github.com/ekmett/lens/
Version: 4.15.4-1
Section: universe/doc