From: Alan Mackenzie <acm@muc.de>
To: npostavs@users.sourceforge.net
Cc: 24870@debbugs.gnu.org, Matt Armstrong <marmstrong@google.com>
Subject: bug#24870: 26.0.50; parse-partial-sexp ignores comment-end
Date: Wed, 14 Dec 2016 19:56:23 +0000 [thread overview]
Message-ID: <20161214195623.GA3881@acm.fritz.box> (raw)
In-Reply-To: <87eg1bcg0y.fsf@users.sourceforge.net>
Hello, Noam.
On Tue, Dec 13, 2016 at 11:04:45PM -0500, npostavs@users.sourceforge.net wrote:
> npostavs@users.sourceforge.net writes:
> > I have tracked the issue down to scan_sexps_forward in syntax.c
> Applying this change which reverts part of [1] seems to fix the issue:
> --- i/src/syntax.c
> +++ w/src/syntax.c
> @@ -3192,7 +3192,11 @@ scan_sexps_forward (struct lisp_parse_state *state,
> while (from < end)
> {
> - if (SYNTAX_FLAGS_COMSTART_FIRST (prev_from_syntax)
> + INC_FROM;
> + code = prev_from_syntax & 0xff;
> +
> + if (from < end
> + && SYNTAX_FLAGS_COMSTART_FIRST (prev_from_syntax)
> && (c1 = FETCH_CHAR (from_byte),
> syntax = SYNTAX_WITH_FLAGS (c1),
> SYNTAX_FLAGS_COMSTART_SECOND (syntax)))
> @@ -3213,8 +3217,6 @@ scan_sexps_forward (struct lisp_parse_state *state,
> }
> else
> {
> - INC_FROM;
> - code = prev_from_syntax & 0xff;
> if (code == Scomment_fence)
> {
> /* Record the comment style we have entered so that only
> Alan, can you explain what the idea behind that change was?
We're talking about 9dcf5998935c8aaa846d7585b81f0dcfe1935b3d from Sun
Mar 20 13:19:48 2016 +0000, still?
The idea is that in a (parse-partial-sexp from to), the end position
might be in the middle of a two character comment marker, such as "/*".
Before this change, it was impossible successfully to use the result of
that operation as the old state for continuing parse-partial-sexp from
that position, since it did not contain enough info to see it was in a
comment after passing the "*"
The change 9dcf599 added an extra element onto the parse state which was
non-nil when we end up after a "/", etc.
> I think it might correspond to this part of the commit message:
> Reformulate code at the top of the main loop correctly to
> recognize comment openers when starting in the middle of one.
> [1]: 9dcf5998935c Sun Mar 20 13:19:48 2016 +0000
> "Amend parse-partial-sexp correctly to handle two character comment delimiters"
With the above in mind, I think we should both check your proposed patch
to make sure it doesn't break the working of 9dcf599.
Thanks for Cc'ing me in on this.
--
Alan Mackenzie (Nuremberg, Germany).
next prev parent reply other threads:[~2016-12-14 19:56 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-03 19:38 bug#24870: 26.0.50; parse-partial-sexp ignores comment-end Andreas Röhler
2016-11-30 9:10 ` Matt Armstrong
2016-11-30 12:37 ` Andreas Röhler
2016-11-30 23:02 ` Matt Armstrong
2016-12-01 1:17 ` npostavs
2016-12-01 8:24 ` Andreas Röhler
2016-12-14 3:00 ` npostavs
2016-12-14 4:04 ` npostavs
2016-12-14 6:45 ` Andreas Röhler
2016-12-14 19:56 ` Alan Mackenzie [this message]
2016-12-15 8:18 ` Andreas Röhler
2016-12-15 16:01 ` Eli Zaretskii
2016-12-15 16:50 ` Alan Mackenzie
2016-12-15 17:59 ` Andreas Röhler
2016-12-14 21:58 ` Alan Mackenzie
2016-12-15 16:33 ` Noam Postavsky
2016-12-15 16:44 ` Alan Mackenzie
2016-12-18 5:39 ` npostavs
2016-12-29 11:14 ` Alan Mackenzie
2016-12-30 1:55 ` npostavs
2017-01-13 2:07 ` npostavs
2017-01-23 20:12 ` Alan Mackenzie
2017-01-24 0:30 ` npostavs
2016-12-01 8:33 ` Andreas Röhler
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