From: Andreas Politz <politza@hochschule-trier.de>
To: Michael Heerdegen <michael_heerdegen@web.de>
Cc: Emacs Development <emacs-devel@gnu.org>
Subject: Re: The symbol `@' and sexp scanning
Date: Thu, 13 Oct 2016 12:19:58 +0200 [thread overview]
Message-ID: <87mvi8tusx.fsf@hochschule-trier.de> (raw)
In-Reply-To: <87a8e8dhq4.fsf@web.de> (Michael Heerdegen's message of "Thu, 13 Oct 2016 05:56:51 +0200")
Michael Heerdegen <michael_heerdegen@web.de> writes:
> FWIW, I can't make much sense out of this description (but the first
> sentence). Nearly anything in an Elisp buffer is inside an
> expression.
I think `expression' can be read as `symbol' in this context.
E.g. calling forward-sexp at the beginning of any of the following
expressions results in the same error.
)
')
'')
'@)
@@)
'@'@')
This is because the sexp scanner treats ' and @ (due to the p flag) in
this context as whitespace, i.e. ignores it (Anyway, that's how I
understand it.). OTOH the following all `work', because there is
something to scan over, before reaching the closing paren.
x)
' x)
@ x)
> [...] evaluating something like that results in an error saying that
> the symbol `@' is unbound, so it doesn't seem to be treated as
> whitespace, but as an expression.
But the way expressions are read and evaluated has nothing to do with
how the function scan-sexp operates.
> Ok, but I guess it's not syntax classification that is problematic but
> how it is treated in the case of the bug.
AFAIK it operates as intended. As to why @ is treated as a prefix
character in an Elisp buffer I don't know.
-ap
next prev parent reply other threads:[~2016-10-13 10:19 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-25 15:23 The symbol `@' and sexp scanning Michael Heerdegen
2016-10-12 14:00 ` Andreas Politz
2016-10-13 3:56 ` Michael Heerdegen
2016-10-13 10:19 ` Andreas Politz [this message]
2016-10-13 12:48 ` Stefan Monnier
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=87mvi8tusx.fsf@hochschule-trier.de \
--to=politza@hochschule-trier.de \
--cc=emacs-devel@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).