a map, where the keys may be complex structured data; documentation

 This type implements maps where the keys are themselves complex structured
 data. For example, the keys may be the abstract syntax trees for a
 programming language. The map is implemented as a trie, so common parts of
 the keys will be shared in the representation. The library provides a generic
 implementation of the data structure, so values of types that have support for
 'Generic' may be automatically used as keys in the map.
 .
 This package provides the documentation for a library for the Haskell
 programming language.
 See http://www.haskell.org/ for more information on Haskell.