> Not quite as simple as it might seem; since you cannot 
> guarantee that a method will be found in any particular
> class you would need some tag mechanism to say that you'd
> already done all required fetching.

Actually you don't. Dan built in this mechanism that the VM signals a
#cannotInterpret: exception if the method dictionary of a class is missing
(nil). AFAIK, this should work perfectly well as long as you don't want to
do this on individual method level.

Hm ... thinking about this - you could do it on a per-method level if you
just tell the other side which selectors are implemented. In this case the
MD could be stubbed out with methods which pull in the appropriate
implementation and continue from there.

Cheers,
  - Andreas