Me too. But if he doesn't answer it he may mean how languages don't have a well designed meta protocol. See the one they built for CLOS in that good book.
This reminded me of an interesting dream I had. I dreamt I created a nice language with a meta protocol. In working with the language and using this protocol I changed the language into a different language which gave me insights on changing that language -- all through meta protocols. I woke up having a distinct feeling of what is means to not be plodding around in a Turing tarpit.
