I was thinking that FilenameLookup and InputName were both being used to do that same thing, so that was why I recommended to remove FilenameLookup and just use InputName instead. For the optparse configs, InputName is usually the option that contains a filename to write results to, and this value is accessed in the Handler so it knows where to write the results to.

It sounds like you're wanting this to be a bit more flexible so that a user can specify both a FilenameLookup and an InputName. Is that right? If so, I'm not totally against it, but at the same time would like to keep these objects as simple as possible to avoid confusion.