multiple-value return

[DLW at MIT-MC]

If you spent more time thinking about how to produce a low-cost
implementation and less time trying to convince us to remove multiple
values from the language, I bet you could come up with
a cheap implementation.  It's largely a matter of how
you choose to expend your efforts.  I'm glad there are
some people on this mailing list who are spending their
time trying to solve problems and figure out good ways
to implement Common Lisp.

Indeed, a very tricky and crafty scheme might be needed
to implement multiple values efficiently.  That's fine.
As long as the user doesn't see it, it's worth it.  I
consider this analogous to the "fast number" scheme in
PDP-10 Maclisp.  Our goal should be to eliminate the
"Lisp is inherently inefficient and can't ever be competitive
with other languages" mentality.

It's also a good thing that Common Lisp is not being designed
purely by a group of language implementors, who have lots
of motivation to eliminate features to keep their own job
easy.  Common Lisp's design has been heavily influenced
by the experience of real users of Maclisp and the Lisp Machine,
who are interested in getting work done and writing code that
can be both efficient and elegant, and who are not interested
especially in keeping things easy for the implementors.  Let
us continue to develop Common Lisp with the needs of the user
foremost in our minds.