[Haskell-cafe] Pattern combinators

All, Wadler posted a blog entry the other day about a paper on pattern-matching in Haskell (http://wadler.blogspot.com/). I've taken a first stab at turning it into actual code for hackage (http://hpaste.org/13215). There are two commented-out definitions that don't type-check, though, and the types are too wild for me to grok. Anybody have any suggestions for 1.) How to fix it and/or 2.) How to use data/type/newtype to simplify the types and make it more manageable? Thanks!