[Haskell-cafe] automatic instance derivation

How do you automatically derive an instance for a data type defined in an imported module? -- automatic instance derivation directly after type declaration data Val1 = V1 Int deriving Show -- manual instance derivation can be in separate file data Val2 = V2 Int instance Show Val2 where show (V2 i) = show i -- Is something like this possible? data Val1 = V1 Int ... derive Show Val2 Thanks, Greg