From: Stefan Monnier via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
To: Lars Ingebrigtsen <larsi@gnus.org>
Cc: Phil Sainty <psainty@orcon.net.nz>,
Stefan Kangas <stefan@marxist.se>,
58513@debbugs.gnu.org
Subject: bug#58513: describe-function should say that defconst variables are constant
Date: Fri, 14 Oct 2022 09:34:00 -0400 [thread overview]
Message-ID: <jwvo7uepmag.fsf-monnier+emacs@gnu.org> (raw)
In-Reply-To: <87edva8seu.fsf@gnus.org> (Lars Ingebrigtsen's message of "Fri, 14 Oct 2022 15:07:53 +0200")
>> Yes, incurring a run-time cost doesn't sound worth it, but we could
>> perhaps make the byte-compiler warn about it.
The byte-compiler already does warn about it, but only if the assignment
is in the same file as the `defconst`.
FWIW, my own local Emacs has `defconst` create actually
constant variables by adding a `SYMBOL_DEFCONST` to `enum
symbol_trapped_write`. Admittedly I didn't make them really constant:
I allow a subsequent `defconst` to change the value set by a previous
`defconst`, but `setq` signals an error just like it does if you try to
`setq` on `enable-multibyte-characters` or on `nil`.
I didn't bother exporting this info to `describe-variable` (and the
byte-compiler) but it would be easy to do.
Stefan
next prev parent reply other threads:[~2022-10-14 13:34 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-14 12:04 bug#58513: describe-function should say that defconst variables are constant Stefan Kangas
2022-10-14 12:23 ` Lars Ingebrigtsen
2022-10-14 12:35 ` Phil Sainty
2022-10-14 12:40 ` Lars Ingebrigtsen
2022-10-14 13:03 ` Stefan Kangas
2022-10-14 13:07 ` Lars Ingebrigtsen
2022-10-14 13:34 ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors [this message]
2022-10-14 14:25 ` Lars Ingebrigtsen
2022-10-14 16:44 ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
2022-10-15 10:04 ` Lars Ingebrigtsen
2022-10-16 20:51 ` Richard Stallman
2022-10-16 21:11 ` Drew Adams
2022-10-17 5:41 ` Stefan Kangas
2022-10-17 10:41 ` Lars Ingebrigtsen
2022-10-15 12:33 ` Stefan Kangas
2022-10-15 14:11 ` Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors
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