I propose to add Functor instances for data types in GetOpt as shown below. I like to have them since I want to build an Option record from sub-records for specific functions, and I like to glue together the sub-records and according argument descriptions. With the Functor instance I can lift the option descriptions for the sub-records to the main Option record. As an interim solution I could prepare a package that provides these instances as orphan instances and has a cabal switch to export the instances from base, once they appear there. Discussion period until 4th of December. PS: I am scared by the idea to have to compile the whole GHC only in order to get 'base' built, and then insert and test these Functor instances. Is there an easier way? PSS: Is it necessary to have GetOpt in base? ---------------------------------- instance Functor ArgOrder where fmap f order = case order of RequireOrder -> RequireOrder Permute -> Permute ReturnInOrder g -> ReturnInOrder $ f.g instance Functor ArgDescr where fmap f d = case d of NoArg a -> NoArg $ f a ReqArg g str -> ReqArg (f.g) str OptArg g str -> OptArg (f.g) str instance Functor OptDescr where fmap f (Option short long arg help) = Option short long (fmap f arg) help