From: Noam Postavsky <npostavs@gmail.com>
To: Michael Heerdegen <michael_heerdegen@web.de>
Cc: "Clément Pit-Claudel" <clement.pitclaudel@live.com>,
31715@debbugs.gnu.org
Subject: bug#31715: cl-incf and cl-decf error out when passed a nil-valued variable as 'offset'
Date: Mon, 04 Jun 2018 20:12:33 -0400 [thread overview]
Message-ID: <871sdm851q.fsf@gmail.com> (raw)
In-Reply-To: <87o9gqw21y.fsf@web.de> (Michael Heerdegen's message of "Tue, 05 Jun 2018 01:43:21 +0200")
Michael Heerdegen <michael_heerdegen@web.de> writes:
> Noam Postavsky <npostavs@gmail.com> writes:
>
>> X is an optional macro parameter, so the "optionalness" applies at
>> compile time.
>
> Are you sure we always treat optional macro parameters like this?
Do DOCSTRING and DECL count?
(defun NAME ARGLIST &optional DOCSTRING DECL &rest BODY)
Since they're obviously not evaluated, it doesn't quite feel the same.
I couldn't find any other cases of optional parameters in core macros.
There is the special form defvar's INITVALUE, but that is treated even
more specially, since it distinguishes nil from omitted.
>> I think that would approximately double the cost of cl-incf in the
>> simple case [...]
Actually, checking again, I seem to be wrong about this; the compiler
knows to elide the extra test if the increment is a constant expression,
so it would only add runtime when incrementing by a computed amount.
next prev parent reply other threads:[~2018-06-05 0:12 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 [this message]
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
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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