From: Tino Calancha <tino.calancha@gmail.com>
To: Eli Zaretskii <eliz@gnu.org>
Cc: 31492@debbugs.gnu.org
Subject: bug#31492: 26.1; query-replace-regexp undo fails in regexps w/o printable chars
Date: Sat, 19 May 2018 23:28:35 +0900 [thread overview]
Message-ID: <87tvr3zpm4.fsf@gmail.com> (raw)
In-Reply-To: <83zi0wgk3d.fsf@gnu.org> (Eli Zaretskii's message of "Sat, 19 May 2018 10:50:30 +0300")
Eli Zaretskii <eliz@gnu.org> writes:
> Thanks, I see the problem now.
>
> However, isn't the root cause in replace--push-stack?
I am not sure; there is something else (see below).
> The relevant
> element of the replacement stack (whose structure, btw, seems not to
> be documented anywhere), is (4 4 *scratch*), whereas I'd expect to see
> (1 4 *scratch) instead, because the replacement was at position 1;
> then setting match-data from this would DTRT.
Yes, that is the logic. The thing is, for some unknown reason to me,
the reported match-data is inexact when there are no printable chars
in the regexp (maybe it's expected and I am wrong on my assumptions).
> IOW, I'm afraid the looking-back solution is ad-hoc, and might not
> work in general, because the real problem is elsewhere. WDYT?
Look what happen in these examples:
(with-temp-buffer
(insert "foo")
(goto-char 1)
(progn (re-search-forward "o$" nil t)
(save-match-data (replace-match "oZZZ"))
(list (point) (match-beginning 0) (match-end 0))))
=> (7 3 7)
;; Now, a regexp with no printable chars
(with-temp-buffer
(insert "foo")
(goto-char 1)
(progn (re-search-forward "$" nil t)
(save-match-data (replace-match "ZZZ"))
(list (point) (match-beginning 0) (match-end 0))))
=> (7 7 7)
;; If this would be (7 4 7), then we could use `looking-at'; we are to
;; the right of the replacement, then we use `looking-back'.
;; But the match was at 4 not at 7
(with-temp-buffer
(insert "foo")
(goto-char 1)
(progn (re-search-forward "$" nil t)
(list (point) (match-beginning 0) (match-end 0))))
=> (4 4 4)
;; We lost the information about the beginning of the match when
;; the regexps lack of printable characters.
next prev parent reply other threads:[~2018-05-19 14:28 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-18 13:27 bug#31492: 26.1; query-replace-regexp undo fails in regexps w/o printable chars Tino Calancha
2018-05-18 14:16 ` Eli Zaretskii
2018-05-18 14:22 ` Tino Calancha
2018-05-18 15:07 ` Eli Zaretskii
2018-05-19 1:46 ` Tino Calancha
2018-05-19 7:50 ` Eli Zaretskii
2018-05-19 14:28 ` Tino Calancha [this message]
2018-05-20 9:29 ` Eli Zaretskii
2018-05-20 11:51 ` Tino Calancha
2018-05-20 11:59 ` Eli Zaretskii
2018-05-20 12:06 ` Tino Calancha
2018-05-20 12:48 ` Eli Zaretskii
2018-05-20 13:46 ` Tino Calancha
2018-05-20 15:47 ` Eli Zaretskii
2018-05-21 1:51 ` Tino Calancha
2018-05-21 15:05 ` Eli Zaretskii
2018-05-23 9:22 ` Tino Calancha
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