[Haskell-cafe] "Combinators for Bi-Directional Tree Transformations: A Linguistic Approach to the View Update Problem" in Haskell

Hi, I wondered if anyone had written an Haskell implementation of the combinators described in: "Combinators for Bi-Directional Tree Transformations: A Linguistic Approach to the View Update Problem" (see the Papers section of http://www.seas.upenn.edu/~harmony/). Harmony's source is in O'Caml so I guess that a translation in Haskell should not be to hard. More in general, is there any work in Haskell on "updateable views" of generic data structures? Thanks, titto