From: Tino Calancha <tino.calancha@gmail.com>
To: Stefan Monnier <monnier@IRO.UMontreal.CA>
Cc: tino.calancha@gmail.com, emacs-devel@gnu.org
Subject: Re: [Emacs-diffs] master 75d9a55: Fix bug 32543
Date: Wed, 19 Sep 2018 02:37:12 +0900 [thread overview]
Message-ID: <87bm8u906v.fsf@calancha-pc.dy.bbexcite.jp> (raw)
In-Reply-To: <jwvbm8vas53.fsf-monnier+emacsdiffs@gnu.org> (Stefan Monnier's message of "Tue, 18 Sep 2018 08:56:52 -0400")
Stefan Monnier <monnier@IRO.UMontreal.CA> writes:
>> +(defun occur--parse-occur-buffer()
>> + "Retrieve a list of the form (BEG END ORIG-LINE BUFFER).
>> +BEG and END define the region.
>> +ORIG-LINE and BUFFER are the line and the buffer from which
>> +the user called `occur'."
>> + (save-excursion
>> + (goto-char (point-min))
>> + (let ((buffer (get-text-property (point-at-bol) 'occur-title))
>> + (beg-pos (get-text-property (point-at-bol) 'region-start))
>> + (end-pos (get-text-property (point-at-bol) 'region-end))
>> + (orig-line (get-text-property (point-at-bol) 'current-line))
>> + beg-line end-line)
>> + (list beg-pos end-pos orig-line buffer))))
>
> I'm curious here:
> - Why use (point-at-bol) since we just moved to (point-min) and hence we
> know that (point-at-bol) == (point-min) == (point)?
In a previous patch I saved the info in one particular position other
that (point-min); finally I saved the info in the entire line as it is
done with the buffer.
> - why store this info in text-properties rather than in buffer-local variables?
I realized the buffer was already saved there with property
`occur-title'; I didn't wanted to scatter around related info.
>> + (let* ((region (occur--parse-occur-buffer))
>> + (region-start (nth 0 region))
>> + (region-end (nth 1 region))
>> + (orig-line (nth 2 region))
>> + (buffer (nth 3 region))
>> + (regexp (car occur-revert-arguments)))
>
> Here you could have used pcase-let:
>
> (pcase-let ((`(,region-start ,region-end ,orig-line ,buffer)
> (occur--parse-occur-buffer))
> (regexp (car occur-revert-arguments)))
Nicer. Thank you!
>> + (with-current-buffer buffer
>> + (when (wholenump orig-line)
>> + (goto-char 1)
>
> I'd recommend `point-min` instead of 1 here.
OK. I always remember the discussion at
https://lists.gnu.org/archive/html/emacs-devel/2009-08/msg00520.html
but I forgot which was the encouraged practice there: in these cases
I follow the 50% rule to reject 0% success ratio (I know, it brings
50% failure ratio: life is full of injustice).
>> + (forward-line (1- orig-line)))
>> + (save-excursion
>> + (if region
>> + (occur regexp nil (list (cons region-start region-end)))
>> + (apply 'occur-1 (append occur-revert-arguments (list (buffer-name))))))))))
>
> `region` is the list which holds (among other things) `buffer`, so if we
> successfully entered (with-current-buffer buffer ...) I can't see how
> `region` could be nil.
Good catch!
It looks like my typo. Probably I wanted here to check if we have
called `occur' before with a non-nil region, i.e., this check:
+ (if (or region-start region-end)
I can push following amend commit:
--8<-----------------------------cut here---------------start------------->8---
--- a/lisp/replace.el
+++ b/lisp/replace.el
@@ -1213,29 +1213,25 @@ occur--parse-occur-buffer
the user called `occur'."
(save-excursion
(goto-char (point-min))
- (let ((buffer (get-text-property (point-at-bol) 'occur-title))
- (beg-pos (get-text-property (point-at-bol) 'region-start))
- (end-pos (get-text-property (point-at-bol) 'region-end))
- (orig-line (get-text-property (point-at-bol) 'current-line))
- beg-line end-line)
+ (let ((buffer (get-text-property (point) 'occur-title))
+ (beg-pos (get-text-property (point) 'region-start))
+ (end-pos (get-text-property (point) 'region-end))
+ (orig-line (get-text-property (point) 'current-line)))
(list beg-pos end-pos orig-line buffer))))
(defun occur-revert-function (_ignore1 _ignore2)
"Handle `revert-buffer' for Occur mode buffers."
(if (cdr (nth 2 occur-revert-arguments)) ; multi-occur
(apply 'occur-1 (append occur-revert-arguments (list (buffer-name))))
- (let* ((region (occur--parse-occur-buffer))
- (region-start (nth 0 region))
- (region-end (nth 1 region))
- (orig-line (nth 2 region))
- (buffer (nth 3 region))
- (regexp (car occur-revert-arguments)))
+ (pcase-let ((`(,region-start ,region-end ,orig-line ,buffer)
+ (occur--parse-occur-buffer))
+ (regexp (car occur-revert-arguments)))
(with-current-buffer buffer
(when (wholenump orig-line)
- (goto-char 1)
+ (goto-char (point-min))
(forward-line (1- orig-line)))
(save-excursion
- (if region
+ (if (or region-start region-end)
(occur regexp nil (list (cons region-start region-end)))
(apply 'occur-1 (append occur-revert-arguments (list (buffer-name))))))))))
--8<-----------------------------cut here---------------end--------------->8---
next prev parent reply other threads:[~2018-09-18 17:37 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20180918123203.24597.514@vcs0.savannah.gnu.org>
[not found] ` <20180918123205.8BE9B204DF@vcs0.savannah.gnu.org>
2018-09-18 12:56 ` [Emacs-diffs] master 75d9a55: Fix bug 32543 Stefan Monnier
2018-09-18 17:37 ` Tino Calancha [this message]
2018-09-18 21:11 ` Stefan Monnier
2018-09-18 22:03 ` Tino Calancha
2018-09-19 13:34 ` Stefan Monnier
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