The finally tagless and "Generics as a Library" styles can - though you loose pattern matching they are arguably still close to grammars.
Pablo Nogueira has posted some examples of open types in "Generics as a Library" tagless style to Haskell cafe: http://www.haskell.org/pipermail/haskell-cafe/2008-July/045028.html _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
