Not having CAR and CDR send messages to entities

[Jeffrey I. Schiller <JIS at MIT-AI>]

cc: BUG-LISPM at MIT-AI

Lose! not only should CAR and CDR when applied to an entity or instance
send a message to that object, but most of the micro-coded functions of 
the lisp machine should also as well (which is what this change is
probably gearing up for...) Entities would serve ideally as a way
to implement abstract data types that my be somewhat like lists and
thus the car and cdr operations would be meaningful. (maybe I want
to make an abstract CONS that also has some other information stashed
away in it like the number of times its cdr was taken so that statistics
for a data base using CONS's could be gathered by inserting these psuedo
CONS's just for experimental runs.) This may be a bad example because it
is just off the top of my head, but the possibilities are limitless. I would
hat to think that this ability be missing because someone (like yourself)
hasn't thought through the possibilities but instead dismissed the whole
idea as "something to be discouraged."

[END OF FLAME]

			-Jeff