I am currently using template haskell to generate code to work on a record data type... This however is not very pretty, and I wondered if there was another way to do what I want in GHC. I need to iterate over the contents of a record for example: data Test = Test { a :: Int, b :: String, c :: Float } If I derive Typeable, I can compare the data-type, but not decompose it, I don't know much about generics, and was wondering if I might be able to do it that way... The functionality I need is equivalent to being able to compare to instances, for example, consider the type above, and the type below: data Test2 = Test2 { x :: Int, y :: String, z :: Float, zz :: String } i need to construct a function that could output the differenc between the types, position at a time, so for the above the output would be: Test2 contains extra String field. or if "y" was to have the type Float, Position 2 : Types differ (Test has String, Test2 has Float) Test2 contains extra String field. I could do this easily if Typeable was a concrete type just by using case statements... Regards, Keean Schupke.