natural transformations; profiling libraries

 A natural transformation transforms a container f a into another
 container g a. Natural transformations act as functor morphisms
 in category theory.
 .
 Technically, f and g should be functors, any correctly-shaped
 structure is allowed.
 .
 This package provides a library for the Haskell programming language, compiled
 for profiling. See http://www.haskell.org/ for more information on Haskell.