express (hackage): Express is a library for manipulating dynamically typed Haskell expressions. It's like  Data.Dynamic  but with support for encoding function aplication and variables.  It provides the  Expr  type and over a hundred functions for building, evaluating, comparing, folding, canonicalizing and matching  Expr s.  See the README and Haddock documentation for more details.
Keywords: bsd3|data|library