From: Noam Postavsky <npostavs@users.sourceforge.net>
To: Michael Heerdegen <michael_heerdegen@web.de>
Cc: 18059@debbugs.gnu.org
Subject: bug#18059: 24.3.92; defvar and special variables
Date: Sat, 10 Feb 2018 14:29:52 -0500 [thread overview]
Message-ID: <87mv0gbq33.fsf@users.sourceforge.net> (raw)
In-Reply-To: <87ha2c7lxy.fsf@web.de> (Michael Heerdegen's message of "Sun, 20 Jul 2014 05:23:21 +0200")
[-- Attachment #1: Type: text/plain, Size: 447 bytes --]
tags 18059 + patch
quit
Michael Heerdegen <michael_heerdegen@web.de> writes:
>>From eval.c:
>
> /* A simple (defvar foo) with lexical scoping does "nothing" except
> declare that var to be dynamically scoped *locally* (i.e. within
> the current file or let-block). */
>
> This behavior isn't obvious, so it should be mentioned in the docstring
> of "defvar" and in
>
> (info "(elisp) Defining Variables")
How about this:
[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #2: patch --]
[-- Type: text/x-diff, Size: 2218 bytes --]
From c284028ba554fb4292d3a3ef275351d5f2dda80e Mon Sep 17 00:00:00 2001
From: Noam Postavsky <npostavs@gmail.com>
Date: Sat, 10 Feb 2018 14:06:05 -0500
Subject: [PATCH] Explain more about (defvar foo) form (Bug#18059)
* doc/lispref/variables.texi (Defining Variables):
* doc/lispref/compile.texi (Compiler Errors): Emphasize that omitting
VALUE for `defvar' marks the variable special only locally.
---
doc/lispref/compile.texi | 4 ++--
doc/lispref/variables.texi | 10 +++++++---
2 files changed, 9 insertions(+), 5 deletions(-)
diff --git a/doc/lispref/compile.texi b/doc/lispref/compile.texi
index 0e39866d34..77d35be1ba 100644
--- a/doc/lispref/compile.texi
+++ b/doc/lispref/compile.texi
@@ -500,8 +500,8 @@ Compiler Errors
@item
Likewise, you can tell the compiler that a variable is defined using
@code{defvar} with no initial value. (Note that this marks the
-variable as special, i.e.@: dynamically bound.) @xref{Defining
-Variables}.
+variable as special, i.e.@: dynamically bound, but only within the
+file.) @xref{Defining Variables}.
@end itemize
You can also suppress any and all compiler warnings within a certain
diff --git a/doc/lispref/variables.texi b/doc/lispref/variables.texi
index e025d3fd10..cd9e1afc97 100644
--- a/doc/lispref/variables.texi
+++ b/doc/lispref/variables.texi
@@ -442,9 +442,13 @@ Defining Variables
evaluated and @var{symbol} is set to the result. But if @var{symbol}
is not void, @var{value} is not evaluated, and @var{symbol}'s value is
left unchanged. If @var{value} is omitted, the value of @var{symbol}
-is not changed in any case. Using @code{defvar} with no value is one
-method of suppressing byte compilation warnings, see @ref{Compiler
-Errors}.
+is not changed in any case.
+
+Note that specifying a value, even @code{nil}, marks the variable as
+special permanently. Whereas if @var{value} is omitted then the
+variable is only marked special locally (i.e. within the current file
+or let-block). This can be useful for suppressing byte compilation
+warnings, see @ref{Compiler Errors}.
If @var{symbol} has a buffer-local binding in the current buffer,
@code{defvar} acts on the default value, which is buffer-independent,
--
2.11.0
next prev parent reply other threads:[~2018-02-10 19:29 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-20 3:23 bug#18059: 24.3.92; defvar and special variables Michael Heerdegen
2018-02-10 19:29 ` Noam Postavsky [this message]
2018-02-10 23:59 ` Michael Heerdegen
2018-02-11 0:17 ` Drew Adams
2018-02-11 0:43 ` Noam Postavsky
2018-02-11 0:38 ` Noam Postavsky
2018-02-11 1:32 ` Michael Heerdegen
2018-02-11 2:26 ` Noam Postavsky
2018-02-11 15:14 ` Stefan Monnier
2018-02-11 15:35 ` Noam Postavsky
2018-02-11 16:38 ` Michael Heerdegen
2018-02-11 17:00 ` Noam Postavsky
2018-02-14 0:27 ` Noam Postavsky
2018-02-18 22:28 ` Noam Postavsky
2018-02-19 1:44 ` Michael Heerdegen
2018-02-21 15:09 ` Noam Postavsky
2018-02-21 16:08 ` Drew Adams
2018-02-21 16:23 ` Noam Postavsky
2018-02-21 16:33 ` Noam Postavsky
2018-02-21 17:15 ` Drew Adams
2018-02-21 18:00 ` Noam Postavsky
2018-02-21 19:14 ` Drew Adams
2018-02-21 19:19 ` Stefan Monnier
2018-02-21 22:20 ` Michael Heerdegen
2018-02-23 14:05 ` Stefan Monnier
2018-02-23 14:55 ` Michael Heerdegen
2018-03-04 23:27 ` Noam Postavsky
2018-03-05 9:51 ` Michael Heerdegen
2018-03-07 13:00 ` Noam Postavsky
2018-03-09 9:58 ` Michael Heerdegen
2018-03-09 13:43 ` Stefan Monnier
2018-03-11 16:45 ` Noam Postavsky
2018-03-11 22:16 ` Drew Adams
2018-03-14 11:15 ` Noam Postavsky
2018-03-23 12:23 ` Noam Postavsky
2018-03-05 15:57 ` Eli Zaretskii
2018-03-08 23:36 ` Noam Postavsky
2018-03-09 0:15 ` Drew Adams
2018-02-21 17:11 ` Drew Adams
2018-02-11 15:57 ` Eli Zaretskii
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
List information: https://www.gnu.org/software/emacs/
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87mv0gbq33.fsf@users.sourceforge.net \
--to=npostavs@users.sourceforge.net \
--cc=18059@debbugs.gnu.org \
--cc=michael_heerdegen@web.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://git.savannah.gnu.org/cgit/emacs.git
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).