Re: Listing headings in dedicated buffer with imenu.

[Stephen Berman <stephen.berman@gmx.net>]

[I sent this yesterday but it hasn't shown up in the list, so
resending.]

On Mon, 29 Jul 2024 11:53:07 +0000 Heime <heimeborgia@protonmail.com> wrote:

> On Monday, July 29th, 2024 at 11:45 PM, Stephen Berman
> <stephen.berman@gmx.net> wrote:
>
>> On Mon, 29 Jul 2024 11:29:07 +0000 Heime heimeborgia@protonmail.com wrote:
>>
>> > Sent with Proton Mail secure email.
>> >
>> > On Monday, July 29th, 2024 at 10:51 PM, Stephen Berman
>> > stephen.berman@gmx.net wrote:
>> >
>> > > On Mon, 29 Jul 2024 10:41:08 +0000 Heime heimeborgia@protonmail.com wrote:
>> > >
>> > > > Sent with Proton Mail secure email.
>> > > >
>> > > > On Monday, July 29th, 2024 at 10:32 PM, Stephen Berman
>> > > > stephen.berman@gmx.net wrote:
>> > > >
>> > > > > On Mon, 29 Jul 2024 10:26:22 +0000 Heime heimeborgia@protonmail.com wrote:
>> > > > >
>> > > > > > Sent with Proton Mail secure email.
>> > > > > >
>> > > > > > On Monday, July 29th, 2024 at 9:33 PM, Stephen Berman
>> > > > > > stephen.berman@gmx.net wrote:
>> > > > > >
>> > > > > > > On Mon, 29 Jul 2024 08:48:38 +0000 Heime
>> > > > > > > heimeborgia@protonmail.com wrote:
>> > > > > > >
>> > > > > > > > I wish to list headings in a dedicated buffer with imenu.
>> > > > > > > > The listing should be in the order in which headings occur
>> > > > > > > > in the buffer.
>> > > > > > > >
>> > > > > > > > Have done the following, but the buffer ends up empty.
>> > > > > > > >
>> > > > > > > > (defun vodil-imenu-bfh ()
>> > > > > > > > "Insert imenu headings in order in a dedicated buffer."
>> > > > > > > > (interactive)
>> > > > > > > >
>> > > > > > > > (let ((imenu-items (imenu--make-index-alist t))
>> > > > > > > > (buffer-name "Imenu Headings"))
>> > > > > > > > (with-current-buffer (get-buffer-create buffer-name)
>> > > > > > > > (erase-buffer)
>> > > > > > > > (dolist (item imenu-items)
>> > > > > > > > (let ((name (car item))
>> > > > > > > > (position (cdr item)))
>> > > > > > > > (when (and (stringp name) (number-or-marker-p position))
>> > > > > > > > (insert (format "%s\n" name)))))
>> > > > > > > > (goto-char (point-min)))
>> > > > > > > > (pop-to-buffer buffer-name)))
>> > > > > > >
>> > > > > > > It works for me, as long as imenu.el is loaded.
>> > > > > > >
>> > > > > > > Steve Berman
>> > > > > >
>> > > > > > What would I need to load it ?
>> > > > >
>> > > > > One way is this:
>> > > > >
>> > > > > (defun vodil-imenu-bfh ()
>> > > > > "Insert imenu headings in order in a dedicated buffer."
>> > > > > (interactive)
>> > > > > (eval-when-compile
>> > > > > (require 'imenu))
>> > > > > (let ((imenu-items (imenu--make-index-alist t))
>> > > > > (buffer-name "Imenu Headings"))
>> > > > > (with-current-buffer (get-buffer-create buffer-name)
>> > > > > (erase-buffer)
>> > > > > (dolist (item imenu-items)
>> > > > > (let ((name (car item))
>> > > > > (position (cdr item)))
>> > > > > (when (and (stringp name) (number-or-marker-p position))
>> > > > > (insert (format "%s\n" name)))))
>> > > > > (goto-char (point-min)))
>> > > > > (pop-to-buffer buffer-name)))
>> > > > >
>> > > > > Steve Berman
>> > > >
>> > > > Right. I have this function that I run. Running vodil-imenu-bfh
>> > > > after executing vodil-imenu-expr gives me rescan in the buffer.
>> > > >
>> > > > (defun vodil-imenu-expr ()
>> > > > "Set up `imenu` to show a list of functions in the current buffer."
>> > > >
>> > > > (interactive)
>> > > >
>> > > > (setq imenu-generic-expression
>> > > > '( ("headings" "^;;;\\s-+\\([HM][[:digit:]]\\)\\s-+\\(.*\\)" 2)))
>> > > >
>> > > > (imenu-add-to-menubar "Iml")
>> > > > (imenu--make-index-alist t)
>> > > > (call-interactively 'imenu))
>> > >
>> > > What were the contents of the current buffer when you executed
>> > > vodil-imenu-expr?
>> > >
>> > > Steve Berman
>> >
>> > I had an elisp file. I ran "M-x vodil-imenu-expr" when in the file to get
>> > the correct imenu entries. But executing "M-x vodil-imenu-bfh" after that
>> > I end up with the buffer "Imenu Headings" having only rescan in it.
>>
>>
>> When I test your code on one of the built-in Emacs Lisp libraries,
>> e.g. avoid.el, then, on invoking vodil-imenu-expr, I get prompted for an
>> Index item, and typing TAB, the Completions buffer pops up containing
>> Rescan and nil. I then type C-g and then M-x vodil-imenu-bfh, and the
>> Imenu Headings buffer pops up containing just Rescan. However, when
>> I start Emacs -Q, evaluate just my emendation of your vodil-imenu-bfh
>> command, then visit avoid.el and invoking vodil-imenu-bfh, the
>> Imenu Headings buffer pops up containing this:
>>
>> Rescan
>> mouse-avoidance-set-pointer-shape
>> mouse-avoidance-point-position
>> mouse-avoidance-set-mouse-position
>> mouse-avoidance-too-close-p
>> mouse-avoidance-banish-destination
>> mouse-avoidance-banish-mouse
>> mouse-avoidance-delta
>> mouse-avoidance-nudge-mouse
>> mouse-avoidance-random-shape
>> mouse-avoidance-ignore-p
>> mouse-avoidance-banish
>> mouse-avoidance-exile
>> mouse-avoidance-fancy
>> mouse-avoidance-mode
>>
>> So at least the contents of avoid.el does not contain a match for your
>> setting of imenu-generic-expression, and presumably the same goes for
>> the file you tested your code on.
>>
>> Steve Berman
>
> Try with this to pick up (defun
>
>  ("defun" "^\\s-*(defun\\s-+\\([[:word:]-]+\\)") 1)
>
> imenu-generic-expression works on my elisp file.  Only the new buffer has *rescan*

Ok, now I see the problem: the list produced by imenu--make-index-alist
contains two elements: ("*Rescan*" . -99) is the first, and the second
is a list whose car is "defun" (or for your file presumably "headings")
and whose cdr is the list of strings from the matching elements
(defuns/headings) in the file with their positions.  What you want to
loop over is just the latter list.  So it should work if you use this in
vodil-imenu-bfh:

  (let ((imenu-items (cdadr (imenu--make-index-alist t)))
        ...)
    ...)

Steve Berman