This library provides strict left folds that stream in constant
 memory, and you can combine folds using Applicative style to derive
 new folds. Derived folds still traverse the container just once and
 are often as efficient as hand-written folds.
 .
 This package provides a library for the Haskell programming language.
 See http://www.haskell.org/ for more information on Haskell.