From: Marco Wahl <marcowahlsoft@gmail.com>
To: Noam Postavsky <npostavs@gmail.com>
Cc: 31061@debbugs.gnu.org
Subject: bug#31061: 27.0.50; next-page of page-ext non-functional in dired
Date: Fri, 27 Apr 2018 13:50:08 +0200 [thread overview]
Message-ID: <84k1ss3m33.fsf@gmail.com> (raw)
In-Reply-To: <84bmezxd5k.fsf@gmail.com>
Noam Postavsky <npostavs@gmail.com> writes:
> Marco Wahl <marcowahlsoft@gmail.com> writes:
>
>> Precondition:
>>
>> - Have a dired with several subdirectories open.
>
> Also, M-x load-lib RET page-ext RET
Yes, thanks.
>> Action:
>>
>> - C-x C-p C-n
>>
>> Expectation:
>>
>> - The dired buffer narrows to the next subdirectory.
>>
>> Observation:
>>
>> - The dired buffer narrows to the current subdirectory.
>
>> * lisp/textmodes/page-ext.el (next-page): Jump ahead page-delimiter if
>> at such before narrow. This fixes the command for dired.
>
> I think the problem is rather that next-page is going an extra page
> backwards even when COUNT was positive, so the fix should be more like
> this (inline version with whitespace changes ignored, full version
> attached):
>
> --- a/lisp/textmodes/page-ext.el
> +++ b/lisp/textmodes/page-ext.el
> @@ -304,6 +304,7 @@ next-page
> (or count (setq count 1))
> (widen)
> ;; Cannot use forward-page because of problems at page boundaries.
> + (if (>= count 0)
> (while (and (> count 0) (not (eobp)))
> (if (re-search-forward page-delimiter nil t)
> nil
> @@ -316,7 +317,7 @@ next-page
> (if (re-search-backward page-delimiter nil t)
> (goto-char (match-beginning 0))
> (goto-char (point-min)))
> - (setq count (1+ count)))
> + (setq count (1+ count))))
> (narrow-to-page)
> (goto-char (point-min))
> (recenter 0))
I think this is a good idea to separate the cases clearly.
I found that with your suggestion next-page with negative argument goes
back one page too much in a dired buffer, though.
I further think that the core of the irritation is that `narrow-to-page'
does not narrow to the following page when on the start of the '\n\n'
page-separator (unlike for the usual '^^L' separator).
Starting with your fix I propose this modification of the else part:
(while (and (< count 1) (not (bobp)))
(if (re-search-backward page-delimiter nil t)
(when (= count 0)
(goto-char (match-end 0)))
(goto-char (point-min)))
(setq count (1+ count)))
This is: go to the end of the delimiter when the final page has been
reached.
Below a diff to make the suggested change perfectly clear, hopefully.
diff --git a/lisp/textmodes/page-ext.el b/lisp/textmodes/page-ext.el
index fbdae5892a..4990fde65a 100644
--- a/lisp/textmodes/page-ext.el
+++ b/lisp/textmodes/page-ext.el
@@ -304,19 +304,21 @@ next-page
(or count (setq count 1))
(widen)
;; Cannot use forward-page because of problems at page boundaries.
- (while (and (> count 0) (not (eobp)))
- (if (re-search-forward page-delimiter nil t)
- nil
- (goto-char (point-max)))
- (setq count (1- count)))
- ;; If COUNT is negative, we want to go back -COUNT + 1 page boundaries.
- ;; The first page boundary we reach is the top of the current page,
- ;; which doesn't count.
- (while (and (< count 1) (not (bobp)))
- (if (re-search-backward page-delimiter nil t)
- (goto-char (match-beginning 0))
- (goto-char (point-min)))
- (setq count (1+ count)))
+ (if (>= count 0)
+ (while (and (> count 0) (not (eobp)))
+ (if (re-search-forward page-delimiter nil t)
+ nil
+ (goto-char (point-max)))
+ (setq count (1- count)))
+ ;; If COUNT is negative, we want to go back -COUNT + 1 page boundaries.
+ ;; The first page boundary we reach is the top of the current page,
+ ;; which doesn't count.
+ (while (and (< count 1) (not (bobp)))
+ (if (re-search-backward page-delimiter nil t)
+ (when (= count 0)
+ (goto-char (match-end 0)))
+ (goto-char (point-min)))
+ (setq count (1+ count))))
(narrow-to-page)
(goto-char (point-min))
(recenter 0))
next prev parent reply other threads:[~2018-04-27 11:50 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-04 14:24 bug#31061: 27.0.50; next-page of page-ext non-functional in dired Marco Wahl
2018-04-25 1:51 ` Noam Postavsky
2018-04-27 11:50 ` Marco Wahl [this message]
2018-04-29 0:13 ` Noam Postavsky
2018-04-29 20:23 ` Marco Wahl
2018-05-03 0:36 ` Noam Postavsky
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