generalized bananas, lenses and barbed wire

 Base functors for fixed points, fixed points, folding, unfolding, refolding,
 Mendler-style iteration, Elgot (co)algebras, and Zygohistomorphic
 prepromorphisms.
 .
 This package provides a library for the Haskell programming language.
 See http://www.haskell.org/ for more information on Haskell.