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Re: Multiple values
- To: JONL at MIT-MC (Jon L White)
- Subject: Re: Multiple values
- From: Guy.Steele at CMU-10A
- Date: Fri ,5 Sep 80 10:21:00 EDT
- Cc: lisp-forum at MIT-MC
I think that on grounds of cleanliness I too would want PROG1
to handle multiple values from its first argument. Without that there doesn't
seem to be any simple way to get something evaluated after the
possibly-multiple-valued value-returning expression is evaluated.
On the S-1 I had planned to use a reserved register in the following way
(I think): for ordinary calls it is not used, and so they are not slowed.
A multiple-value call must push the register and then set it to 1;
on return the caller must pop it. A callee which returns multiple
values sets the register to the number of values it is returning for
the caller to look at. Hmm, there's a problem here. I'll have to
look up the true solution.