From: Noam Postavsky <npostavs@gmail.com>
To: "Clément Pit-Claudel" <clement.pitclaudel@live.com>
Cc: 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 18:58:01 -0400 [thread overview]
Message-ID: <874lii88hy.fsf@gmail.com> (raw)
In-Reply-To: <1dff07f6-8da4-4e4c-a700-0bc39d6f2aa6@live.com> ("Clément Pit-Claudel"'s message of "Mon, 4 Jun 2018 16:06:55 -0400")
Clément Pit-Claudel <clement.pitclaudel@live.com> writes:
> The following works:
> (let ((x 1)) (cl-incf x nil))
>
> … but following raises "setq: Wrong type argument: number-or-marker-p, nil":
> (let ((x 1) (y nil)) (cl-incf x y))
>
> … yet the docs say this, which suggests that both should work:
> (cl-incf PLACE &optional X)
> Increment PLACE by X (1 by default).
X is an optional macro parameter, so the "optionalness" applies at
compile time.
> The issue comes from the expansion of cl-incf:
>
> (defmacro cl-incf (place &optional x) …
> (if (symbolp place)
> (list 'setq place (if x (list '+ place x) (list '1+ place)))
> (list 'cl-callf '+ place (or x 1))))
>
> Shouldn't that `if x' check be quoted? Same for the second branch of the if (shouldn't the `(or x 1)' part be quoted, too?)
I think that would approximately double the cost of cl-incf in the
simple case. And since you would expect cl-incf to be used in loops a
lot, that seems like a bad idea.
next prev parent reply other threads:[~2018-06-04 22:58 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 [this message]
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
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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