From: "Clément Pit-Claudel" <clement.pitclaudel@live.com>
To: Noam Postavsky <npostavs@gmail.com>
Cc: Michael Heerdegen <michael_heerdegen@web.de>, 31715@debbugs.gnu.org
Subject: bug#31715: cl-incf and cl-decf error out when passed a nil-valued variable as 'offset'
Date: Tue, 5 Jun 2018 19:01:56 -0400 [thread overview]
Message-ID: <6176bcee-a8da-8547-762b-4174652ad2a0@live.com> (raw)
In-Reply-To: <87k1rc7sly.fsf@gmail.com>
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On 2018-06-05 18:53, Noam Postavsky wrote:
> Both SBCL and CLisp throw an error for (let ((x 1) (y nil)) (incf x y)),
> although I can't see anything in the Common Lisp spec to decide either
> way. E.g., cltl2 says:
>
> If delta is not supplied, then the number in place is changed by 1.
>
> https://www.cs.cmu.edu/Groups/AI/html/cltl/clm/node125.html
Thanks for looking up the spec and testing other implementations. I'm not sure what to make of the result with SBCL and CLisp, since (incf x nil) also fails in both of them (whereas it works for us, since we can't distinguish nil and unspecified).
>> In the rest of Emacs there are lots of other examples. Many of them
>> (for example semantic-find-tags-by-name or calendar-increment-month)
>> seem to work when passed a nil-valued variable, but many others behave
>> like cl-incf (for example gnus-summary-article-score).
>
> I don't think those are great examples of macros to emulate.
Agreed, I was just collecting other examples, both in support and against my point.
Clément.
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next prev parent reply other threads:[~2018-06-05 23:01 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-04 20:06 bug#31715: cl-incf and cl-decf error out when passed a nil-valued variable as 'offset' Clément Pit-Claudel
2018-06-04 22:58 ` Noam Postavsky
2018-06-04 23:43 ` Michael Heerdegen
2018-06-05 0:12 ` Noam Postavsky
2018-06-05 0:40 ` Michael Heerdegen
2022-04-21 13:11 ` Lars Ingebrigtsen
2018-06-05 15:19 ` Clément Pit-Claudel
2018-06-05 22:53 ` Noam Postavsky
2018-06-05 23:01 ` Clément Pit-Claudel [this message]
2018-06-05 23:26 ` Noam Postavsky
2018-06-05 23:36 ` Clément Pit-Claudel
2018-06-06 0:32 ` Michael Heerdegen
2018-06-06 0:37 ` Noam Postavsky
2018-06-05 15:03 ` Clément Pit-Claudel
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