A library of extra functions for the standard Haskell libraries. Most
functions are simple additions, filling out missing functionality. A few
functions are available in later versions of GHC, but this package makes
them available back to GHC 7.2. The module "Extra" documents all functions
provided by this library. Modules such as "Data.List.Extra" provide extra
functions over "Data.List" and also reexport "Data.List". Users are
recommended to replace "Data.List" imports with "Data.List.Extra" if they
need the extra functionality.

WWW: https://github.com/ndmitchell/extra#readme