From: Stefan Monnier <monnier@iro.umontreal.ca>
To: Michael Heerdegen <michael_heerdegen@web.de>
Cc: Emacs Development <emacs-devel@gnu.org>
Subject: Re: defvar without value
Date: Tue, 31 Mar 2020 20:59:17 -0400 [thread overview]
Message-ID: <jwvtv24f2m7.fsf-monnier+emacs@gnu.org> (raw)
In-Reply-To: <87k1302htp.fsf@web.de> (Michael Heerdegen's message of "Wed, 01 Apr 2020 02:03:14 +0200")
> Using `defvar' (on top-level) without specifying a value differs in two
> ways from calls that specify a value: (1) the variable's value is not
> set, and (2) the variable is made special only in the context of the
> (rest of the) current file or buffer.
>
> I wonder if it is good that these two things are chained together, and
> if there are alternatives to what we have now.
I guess we could add something like (defvar-dynamic VAR) which sets the
`special` bit on the variable, just like (defvar VAR VAL) does, but
leaves the variable's value unchanged (currently, you'd have to do
(progn (defvar VAR 'dummy) (makunbound 'VAR)) to get a similar effect).
Similarly, we could add something like (defvar-lexical VAR VAL) which
defines the var and sets it but doesn't set the `special` bit
(currently, we have `internal-make-var-non-special` to serve the same
need).
Stefan
next prev parent reply other threads:[~2020-04-01 0:59 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-01 0:03 defvar without value Michael Heerdegen
2020-04-01 0:36 ` Drew Adams
2020-04-01 0:59 ` Stefan Monnier [this message]
2020-04-01 22:45 ` Michael Heerdegen
2020-04-02 2:37 ` Stefan Monnier
2020-04-09 1:52 ` Michael Heerdegen
2020-04-09 2:04 ` Emanuel Berg via Emacs development discussions.
2020-04-09 2:20 ` Stefan Monnier
2020-04-09 23:34 ` Emanuel Berg via Emacs development discussions.
2020-04-10 15:20 ` Bruno Félix Rezende Ribeiro
2020-04-10 23:07 ` Emanuel Berg via Emacs development discussions.
2020-04-10 21:57 ` Michael Heerdegen
2020-04-01 1:21 ` Noam Postavsky
2020-04-01 1:53 ` Michael Heerdegen
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