From Newsgroup: gnu.emacs.help

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Hello,

I am struggling to get which-function-mode activated in a derived
mode. I have trimmed the problem down successfully to a minimum example
that looks as follows:


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(add-to-list 'auto-mode-alist '("\\.mini\\'" . mini-mode))

(defun mini-mode-which-func ()
"XXX")

(add-hook 'which-func-functions #'mini-mode-which-func)

(define-derived-mode mini-mode
text-mode "Mini"
"Major mode for editing .mini files."
(add-hook 'mini-mode-hook #'(lambda ()
(setq-local foo "bar")
(which-function-mode 1)
(setq-local which-function-mode t)
(setq-local which-func-mode t)
(message "Hook has been setup.")))
(run-mode-hooks))

(provide 'mini)

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When I start GUN Emacs 27.1 (Devuan Linux) with

emacs -Q -l mini-mode.el foo.mini

it opens an empty foo.mini correcty in mini-mode, as confirmed by C-h m
and the mode line.

C-h v foo RET

shows that foo is locally set to "bar", but void globally. Likewise, which-function-mode (the variable) is set to t, but which-func-mode is
nil, even though I have set it to t in my mode's hook. This hook is
executed, as confirmed by the text message "Hook has been setup"
immediately after opening foo.mini.

However, the dummy "XXX" used as "which-func" is not shown in the mode
line.

Only if I run

M-x mini-mode RET

again or do a

M-: (setq-local which-func-mode t) RET

the "XXX" appears in the mode line, as desired.

What I am doing wrong or how do I get which-func-mode activated in my
derived mode automatically?

Pointers much appreciated!

Best regards

Axel

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From Newsgroup: gnu.emacs.help

Dear Alex,

Axel Reichert <mail@axel-reichert.de> a |-crit :

Hello,

I am struggling to get which-function-mode activated in a derived
mode. I have trimmed the problem down successfully to a minimum example
that looks as follows:

(add-to-list 'auto-mode-alist '("\\.mini\\'" . mini-mode))

(defun mini-mode-which-func ()
"XXX")

(add-hook 'which-func-functions #'mini-mode-which-func)

(define-derived-mode mini-mode
text-mode "Mini"
"Major mode for editing .mini files."
(add-hook 'mini-mode-hook #'(lambda ()
(setq-local foo "bar")
(which-function-mode 1)
(setq-local which-function-mode t)
(setq-local which-func-mode t)
(message "Hook has been setup.")))
(run-mode-hooks))

(provide 'mini)

When I start GUN Emacs 27.1 (Devuan Linux) with

emacs -Q -l mini-mode.el foo.mini

it opens an empty foo.mini correcty in mini-mode, as confirmed by C-h m
and the mode line.

C-h v foo RET

shows that foo is locally set to "bar", but void globally. Likewise, which-function-mode (the variable) is set to t, but which-func-mode is
nil, even though I have set it to t in my mode's hook. This hook is
executed, as confirmed by the text message "Hook has been setup"
immediately after opening foo.mini.

However, the dummy "XXX" used as "which-func" is not shown in the mode
line.

Only if I run

M-x mini-mode RET

again or do a

M-: (setq-local which-func-mode t) RET

the "XXX" appears in the mode line, as desired.

What I am doing wrong or how do I get which-func-mode activated in my
derived mode automatically?

Pointers much appreciated!

I do not know really the issue, however I think that it has to do with
imenu. It looks like which-functions-mode uses imenu to understand
where begins and ends a function. Trying to use imenu in Text Mode
throws an error.

Regards,
Thomas
--- Synchronet 3.21d-Linux NewsLink 1.2

From Newsgroup: gnu.emacs.help

Thomas Dupond <thomas@dupond.eu> writes:

Axel Reichert <mail@axel-reichert.de> a |-crit :

What I am doing wrong or how do I get which-func-mode activated in my
derived mode automatically?

Pointers much appreciated!

I do not know really the issue, however I think that it has to do with
imenu. It looks like which-functions-mode uses imenu to understand
where begins and ends a function. Trying to use imenu in Text Mode
throws an error.

I had this suspicion as well, but discarded it because the second

M-x mini-mode

succeeds, as does setting which-func-mode to t manually. However, just
for the sake of testing, I have now based my mini-mode not on text-mode,
but on c-mode, and, heureka, the "XXX" is shown in the mode line!

Now I will search the docs about Imenu and try to find out how to teach
it that text-mode is not a no-go. Let's see.

Thanks for the hint!

Axel
--- Synchronet 3.21d-Linux NewsLink 1.2

From Newsgroup: gnu.emacs.help

Dear Alex,

Axel Reichert <mail@axel-reichert.de> a |-crit :

Thomas Dupond <thomas@dupond.eu> writes:

Axel Reichert <mail@axel-reichert.de> a |-crit :

What I am doing wrong or how do I get which-func-mode activated in my
derived mode automatically?

Pointers much appreciated!

I do not know really the issue, however I think that it has to do with
imenu. It looks like which-functions-mode uses imenu to understand
where begins and ends a function. Trying to use imenu in Text Mode
throws an error.

I had this suspicion as well, but discarded it because the second

M-x mini-mode

succeeds, as does setting which-func-mode to t manually. However, just
for the sake of testing, I have now based my mini-mode not on text-mode,
but on c-mode, and, heureka, the "XXX" is shown in the mode line!

Now I will search the docs about Imenu and try to find out how to teach
it that text-mode is not a no-go. Let's see.

I delved a little bit deeper and apparently you should be able to do
what you want after you have defined the variable
imenu-generic-expression or the variable imenu-create-index-function.
Fortran mode uses the former and Org mode the latter (respectively in fortran-mode.el and org-compat.el).

For example I wrote this based on your first message and it displays
the current markdown-like title (only for lines beginning
with one or two stars) with which-func:

(add-to-list 'auto-mode-alist '("\\.mini\\'" . mini-mode))

(define-derived-mode mini-mode
text-mode "Mini"
"Major mode for editing .mini files."
(which-function-mode 1)
(defvar mini-imenu-generic-expression
(list
(list
nil
"^\*\\ \\(.*\\)$"
1)
(list
nil
"^\*\*\\ \\(.*\\)$"
1)))
(set (make-local-variable 'imenu-generic-expression)
mini-imenu-generic-expression))

(provide 'mini)

--
Regards,
Thomas
--- Synchronet 3.21d-Linux NewsLink 1.2

From Newsgroup: gnu.emacs.help

Thomas Dupond <thomas@dupond.eu> writes:

I delved a little bit deeper and apparently you should be able to do
what you want after you have defined the variable
imenu-generic-expression or the variable imenu-create-index-function.
Fortran mode uses the former and Org mode the latter (respectively in fortran-mode.el and org-compat.el).

Many thanks for your research! It works now:

(add-to-list 'auto-mode-alist '("\\.mini2\\'" . mini2-mode))

(defun mini2-mode-which-func ()
"XXX")

(add-hook 'which-func-functions #'mini2-mode-which-func)

(define-derived-mode mini2-mode
text-mode "Mini2"
"Major mode for editing .mini2 files."
(which-function-mode 1)
(defvar mini2-imenu-generic-expression
(list
(list
nil
"^\*\\ \\(.*\\)$"
1)
(list
nil
"^\*\*\\ \\(.*\\)$"
1)))
(set (make-local-variable 'imenu-generic-expression)
mini2-imenu-generic-expression))

(provide 'mini2)

correctly shows "XXX" in the mode line after

emacs -Q -l mini2-mode.el foo.mini2

Thanks again and best regards

Axel (not Alex)
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