Generational Interfaces

[Carl Banks]

On Jan 26, 12:32 am, Paul Rubin <http://phr...@NOSPAM.invalid> wrote:
> Carl Banks <pavlovevide... at gmail.com> writes:
> > AirplaneInterface = InterfaceTracker("Airplane")
> > ...
> >         set_up_initial_state()
> >         ...
> >         AirplaneInterface.report(self)
> > Thoughts?  (Surely someone's thought to do this before.)
>
> A decorator might express the idea a little more naturally.

Details.  I didn't thoroughly map out the whole system in my head or
anything.


> Also, I'd say the interface tracker really should be told explicitly
> when something is part of the interface and when it's specific to a
> particular class implementing the interface.  It shouldn't try to
> guess this based on some operation appearing in more than one class.

Well, that kind of defeats the purpose, doesn't it?

If you're going to all that trouble, it's probably not too much more
trouble to just manually specify the whole interface and be done with
it.  Anyways you don't always know what's going to end up as part of
the interface in early stages.

It goes without saying there should be ways to manually override the
interface tracker's decision, but that falls more into the category
"So your interface tracker has guessed wrong".


> Maybe there's some operation done on all jet planes and on no
> propeller planes, that shouldn't be part of the top level airplane
> interface.

Well, then the interface tracker would see that some member (say,
"set_mixture") exists on some objects and not others, and would
consider it not part of the interface.  Only members that are defined
universally or nearly universally would be considered part of the
interface.

Now if you're concerned that you could implement a bunch of prop
planes, and then suddenly you throw a jet in there and it breaks
everything, there's a simple solution: convert the AirplaneInterface
to PropAirplaneInterface.  (Yeah, suck it up and replace it
everywhere.  If you haven't implemented any jets you shouldn't have
released the damn thing yet.)  Create a new JetAirplaneInterface
tracker and (if useful) define Airplane as the union of the two.

Obviously something like this could get really intelligent--it could
perhaps work out the difference between props and jets itself (using,
say, statistical correlation).  I bet there are some high-end code
analysis tools for various languages that do stuff like that.  (But I
doubt many of them factor time into it; my idea was to incorporate
time into it somehow.  Something does not become part of an interface
until it's universally used AND has been around for awhile.)


Carl Banks