From: Stefan Monnier <monnier@iro.umontreal.ca>
To: emacs-devel@gnu.org
Subject: Re: Why is FUNC in cl-callf not allowed to be an expression?
Date: Wed, 29 May 2019 13:02:59 -0400 [thread overview]
Message-ID: <jwvr28hryxn.fsf-monnier+emacs@gnu.org> (raw)
In-Reply-To: 877eac3fzo.fsf@web.de
>> Indeed, they're closely related but symbol-macrolet does not "evaluates"
>> anything at the "binding" site. Also it can also be used for purposes
>> different from "places", e.g. to keep a log of all the accessed to
>> a "variable" (tho, we could just as well create a (journaled PLACE)
>> pseudo place which would record accesses in the very same way).
>
> I also come to the conclusion that symbol-macrolet and place binding are
> two different things.
Right. I think you can always use one to implement the functionality of
the other, but they're different.
> OTOH, `symbol-macrolet' might be used for arbitrary calculations. It
> would be surprising (wrong) if in
>
> (symbol-macrolet ((r (list (random))))
> (list r r))
>
> the `random' function would be called only once.
Indeed, with gv-place-bind you'd need to use something like
(gv-place-bind ((r (gv-cbn (list (random)))))
(list r r))
for some definition of `gv-cbn` such as
(defun gv-cbn (x)
(declare (gv-expander (lambda (do)
(funcall do x (lambda (v) `(setf ,x ,v))))))
x)
-- Stefan
next prev parent reply other threads:[~2019-05-29 17:02 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-09 21:52 Why is FUNC in cl-callf not allowed to be an expression? Michael Heerdegen
2019-05-10 0:47 ` Stefan Monnier
2019-05-10 11:32 ` Michael Heerdegen
2019-05-10 13:28 ` Stefan Monnier
2019-05-10 14:19 ` Stefan Monnier
2019-05-10 14:22 ` Stefan Monnier
2019-05-10 15:18 ` Michael Heerdegen
2019-05-13 16:47 ` Stefan Monnier
2019-05-14 12:36 ` Michael Heerdegen
2019-05-14 23:32 ` Michael Heerdegen
2019-05-15 2:02 ` Stefan Monnier
2019-05-15 16:38 ` Michael Heerdegen
2019-05-15 17:19 ` Michael Heerdegen
2019-05-16 2:18 ` Michael Heerdegen
2019-05-16 13:12 ` Stefan Monnier
2019-05-16 14:37 ` Michael Heerdegen
2019-05-16 15:09 ` Michael Heerdegen
2019-05-16 19:34 ` Stefan Monnier
2019-05-16 21:46 ` Michael Heerdegen
2019-05-16 23:06 ` Stefan Monnier
2019-05-17 22:53 ` Michael Heerdegen
2019-05-18 14:09 ` Stefan Monnier
2019-05-20 23:25 ` Michael Heerdegen
2019-05-21 2:01 ` Stefan Monnier
2019-05-21 2:47 ` Michael Heerdegen
2019-05-21 10:16 ` Noam Postavsky
2019-05-21 16:38 ` Michael Heerdegen
2019-05-21 17:38 ` Stefan Monnier
2019-05-21 7:26 ` Andy Moreton
2019-05-23 23:02 ` Michael Heerdegen
2019-05-22 1:00 ` Michael Heerdegen
2019-05-23 1:50 ` Michael Heerdegen
2019-05-23 3:38 ` Stefan Monnier
2019-05-23 23:38 ` Michael Heerdegen
2019-05-24 15:29 ` Stefan Monnier
2019-05-28 19:54 ` Michael Heerdegen
2019-05-27 0:20 ` Michael Heerdegen
2019-05-29 17:02 ` Stefan Monnier [this message]
2019-05-15 19:17 ` Michael Heerdegen
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