Re: insert gives args out of range

[Heime <heimeborgia@protonmail.com>]

On Saturday, August 17th, 2024 at 3:34 AM, Stephen Berman <stephen.berman@gmx.net> wrote:

> On Fri, 16 Aug 2024 15:21:12 +0000 Heime heimeborgia@protonmail.com wrote:
> 
> > On Saturday, August 17th, 2024 at 3:16 AM, Stephen Berman
> > stephen.berman@gmx.net wrote:
> > 
> > > On Fri, 16 Aug 2024 15:09:55 +0000 Heime heimeborgia@protonmail.com wrote:
> > > 
> > > > On Saturday, August 17th, 2024 at 3:01 AM, Heime
> > > > heimeborgia@protonmail.com wrote:
> > > > 
> > > > > On Saturday, August 17th, 2024 at 12:26 AM, Stephen Berman
> > > > > stephen.berman@gmx.net wrote:
> > > > > 
> > > > > > On Fri, 16 Aug 2024 12:10:48 +0000 Heime heimeborgia@protonmail.com wrote:
> > > > > > 
> > > > > > > On Saturday, August 17th, 2024 at 12:03 AM, Heime
> > > > > > > heimeborgia@protonmail.com wrote:
> > > > > > > 
> > > > > > > > On Friday, August 16th, 2024 at 11:51 PM, Stephen Berman
> > > > > > > > stephen.berman@gmx.net wrote:
> > > > > > > > 
> > > > > > > > > On Fri, 16 Aug 2024 10:59:09 +0000 Heime
> > > > > > > > > heimeborgia@protonmail.com wrote:
> > > > > > > > > 
> > > > > > > > > > On Friday, August 16th, 2024 at 10:20 PM, Heime
> > > > > > > > > > heimeborgia@protonmail.com wrote:
> > > > > > > > > > 
> > > > > > > > > > > On Friday, August 16th, 2024 at 9:54 PM, Stephen Berman
> > > > > > > > > > > stephen.berman@gmx.net wrote:
> > > > > > > > > > > 
> > > > > > > > > > > > On Fri, 16 Aug 2024 09:24:23 +0000 Heime
> > > > > > > > > > > > heimeborgia@protonmail.com wrote:
> > > > > > > > > > > > 
> > > > > > > > > > > > > I want to display text starting from "(defun" up to the
> > > > > > > > > > > > > second blank
> > > > > > > > > > > > > line that is encountered.
> > > > > > > > > > > > > 
> > > > > > > > > > > > > But with this code I get
> > > > > > > > > > > > > 
> > > > > > > > > > > > > insert: Args out of range: #<buffer Defun Sections>, 2706, 2804
> > > > > > > > > > > > > 
> > > > > > > > > > > > > (defun display-text ()
> > > > > > > > > > > > > "Display the text between a line starting with '(defun' and
> > > > > > > > > > > > > the second
> > > > > > > > > > > > > blank line."
> > > > > > > > > > > > > (interactive)
> > > > > > > > > > > > > (let ((output-buffer (get-buffer-create "Defun Sections")))
> > > > > > > > > > > > > (with-current-buffer output-buffer
> > > > > > > > > > > > > (erase-buffer)) ;; Clear previous contents
> > > > > > > > > > > > > (save-excursion
> > > > > > > > > > > > > (goto-char (point-min))
> > > > > > > > > > > > > (while (re-search-forward "^(defun" nil t)
> > > > > > > > > > > > > (let ((start (match-beginning 0))
> > > > > > > > > > > > > (blank-lines 0)
> > > > > > > > > > > > > end)
> > > > > > > > > > > > > ;; Move forward to find the second blank line
> > > > > > > > > > > > > (while (and (< blank-lines 2)
> > > > > > > > > > > > > (re-search-forward "^\\s-*$" nil t))
> > > > > > > > > > > > > (setq blank-lines (1+ blank-lines)))
> > > > > > > > > > > > > (setq end (point))
> > > > > > > > > > > > > ;; Ensure the range is valid before inserting
> > > > > > > > > > > > > (when (> end start)
> > > > > > > > > > > > > (with-current-buffer output-buffer
> > > > > > > > > > > > > (insert (buffer-substring-no-properties start end) "\n"))))))
> > > > > > > > > > > > > ;; Display the output buffer
> > > > > > > > > > > > > (display-buffer output-buffer)))
> > > > > > > > > > > > 
> > > > > > > > > > > > You've set `start' and` end' in a different buffer than
> > > > > > > > > > > > output-buffer
> > > > > > > > > > > > but you're invoking buffer-substring-no-properties with these
> > > > > > > > > > > > values in
> > > > > > > > > > > > output-buffer, which you've erased, so those values are not in
> > > > > > > > > > > > the range
> > > > > > > > > > > > of possible values in output-buffer. Try let-binding the
> > > > > > > > > > > > result of
> > > > > > > > > > > > invoking buffer-substring-no-properties before the second
> > > > > > > > > > > > invocation of
> > > > > > > > > > > > with-current-buffer.
> > > > > > > > > > > > 
> > > > > > > > > > > > Steve Berman
> > > > > > > > > > 
> > > > > > > > > > I updated as suggested. Although I get the output, the search
> > > > > > > > > > stops on
> > > > > > > > > > the first
> > > > > > > > > > blank line rather than on the second blank line.
> > > > > > > > > 
> > > > > > > > > Consider a buffer "test" with the following content (two blank lines
> > > > > > > > > between the defuns):
> > > > > > > > > 
> > > > > > > > > ;;;;;;;;;;;;;
> > > > > > > > > 
> > > > > > > > > (defun f1 ()
> > > > > > > > > (ignore))
> > > > > > > > > 
> > > > > > > > > (defun f2 ()
> > > > > > > > > (ignore))
> > > > > > > > > ;;;;;;;;;;;;;
> > > > > > > > > 
> > > > > > > > > When you call `display-text' in "test", the first evaluation of the
> > > > > > > > > sexp (re-search-forward "^\\s-*$" nil t) moves point to the first blank
> > > > > > > > > line below the first defun. Where is point after the second evaluation
> > > > > > > > > of that sexp? - Steve Berman
> > > > > > > > 
> > > > > > > > It is still at the beginning of the first blank line.
> > > > > > > 
> > > > > > > I do not understand why this happens. Because (point) after
> > > > > > > re-search-forward should give me the position at the beginning of the
> > > > > > > second blank line that is encountered.
> > > > > > 
> > > > > > The sexp (re-search-forward "^\\s-*$" nil t) succeeds if it find a line
> > > > > > containing only zero or more whitespace characters and moves point to
> > > > > > the end of the match. If point is on a blank line, the search succeeds,
> > > > > > but since the beginning and end of the match coincide, point does not
> > > > > > move. If you want point to move, your code needs to accommodate this
> > > > > > case. - Steve Berman
> > > > > 
> > > > > Have printed start and end just after (setq end (point))
> > > > > 
> > > > > (message "Start: %d, End: %d" start end)
> > > > > 
> > > > > And the values for start and end are different.
> > > 
> > > `start' holds the value of the beginning of the match for "^(defun", but
> > > your problem arises when searching for "^\\s-*$"; you'll see it if you
> > > change the message to this:
> > > 
> > > (message "Start: %d, End: %d" (match-beginning 0) (match-end 0))
> > > 
> > > > When the first blank is reached, point moves to that blank, the next search
> > > > keeps point at the same place rather than moving to the next blank line.
> > > 
> > > For the reason I explained above. - Steve Berman
> > 
> > I have solved the problem by adding (forward-line 1) after setting blank-lines
> > 
> > (while (and (< blank-lines 2)
> > (re-search-forward "^\\s-*$" nil t))
> > (setq blank-lines (1+ blank-lines))
> > ;; Move point forward to avoid re-matching the same blank line
> > (forward-line 1))
> > 
> > Could this fail on some circumstances ?
> 
> 
> Depends on what you consider failure: with the buffer "test" I gave as
> an example above, output-buffer contains not just two but three empty
> lines between the two defuns, and not just one but two empty lines at
> the end; is that what you want?
> 
> Steve Berman

By failure, I mean this: Could Emacs fire an error buffer based on some unforeseen
structure of the file when re-search-forward executes ?