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changing multiple-value calls in emacs code.

From: Dave Goel
Subject: changing multiple-value calls in emacs code.
Date: Fri, 13 Mar 2009 15:42:02 -0400
User-agent: Gnus/5.110006 (No Gnus v0.6) Emacs/21.4 (gnu/linux)

There are a very few places in emacs that do things like
(multiple-value-bind).  As we know, this does not in reality use any
m-v facility, mostly it is meant to bind vars to a list, rather than
to a host of values.  Indeed, (values-list) is an identity.

In such cases, the right thing to do would be to change such calls:

(multiple-value-setq (a b) (foo))


(multiple-value-setq (a b) (values-list (foo))).

While the former is == the latter, the latter is the proper "RIGHT"
way of setq-ing a and b to members of a list.

I have committed some such changes. Please let me know if you think I did
anything wrong.

It is just a cosmetic change, since values-list just returns its
argument unchanged.


It is much rarer still that a function actually invokes any m-v
facility and returns (values ..) in its output.  This happens only in
mh.el .. In emacs, we want to stay away using m-v, and such (values)
should be changed to (list.. ).  Of course, this is again a cosmetic

The uses of these values should again be used by (multiple-value-bind
... (values-list ... ))


I restress that any changes I made above are merely cosmetic changes.

(But, with a proper m-v facility, like the one I am proposing, these
changes will matter.  Furthermore, these changes ensure that we never
use m-v facitily by default any way.)

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