Re: Colourising fill-column-indicator

[Heime]

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On Wednesday, December 4th, 2024 at 5:11 PM, Michael Heerdegen 
<michael_heerdegen@web.de> wrote:

> Heime via Users list for the GNU Emacs text editor
> help-gnu-emacs@gnu.org writes:
> 
> > Where should the following commands be called?
> > 
> > (setq-default display-fill-column-indicator-character ?\u2503)
> > 
> > (set-face-attribute
> > 'fill-column-indicator nil :background "green" :height 1.0)
> > 
> > Are they to be called before display-fill-column-indicator-mode?
> 
> 
> In a buffer with display-fill-column-indicator-mode enabled the
> `setq-default' will of course have no effect on the binding of the local 
> variable` display-fill-column-indicator-character'.
> 
> I'm totally guessing what you are asking for since you seldom tell what
> you are doing, what you are seeing, and what you want to achieve.
> 
> Michael.

Because  setq-default have no effect on the binding of the local variable,
how does one set the local value?  With a mode hook?

I want to have the same character indicator whenever one enables the mode.

Consider the following function

(defun linwrap (actm)
  "Toggle display of fill-column indicator."

  (interactive
   (list
    (let ( (cseq '("local" "toggle" "global" "disable")) )
      (completing-read "Context: " cseq nil t "toggle"))))

  (setq-default display-fill-column-indicator-character ?\u2503)

  (set-face-attribute
    'fill-column-indicator nil :background "green" :height 1.0)

  (cond
    ((equal actm "local") (display-fill-column-indicator-mode))

    ((equal actm "global") (global-display-fill-column-indicator-mode))

    ((equal actm "mode-hook")
       (add-hook 'prog-mode-hook #'display-fill-column-indicator-mode))

    ((equal actm "toggle") (display-fill-column-indicator-mode 'toggle))

    (t
       ;; Use mode variable to test whether mode was activated
       (if global-display-fill-column-indicator-mode
           (global-display-fill-column-indicator-mode -1)
         (display-fill-column-indicator-mode -1))) ))