Emacs - Mode Line Update

Question

I customized my mode-line on my laptop (emacs 23.3) and it works perfect.

But when I tried to get it to work on my desktop at school (emacs 21.4) it doesn't update when using Ctrl-f, Ctrl-b, Ctrl-a, etc. unless I actually modify the buffer.

I made a case statement to change the code depending on the computer I'm on, so all the functions work properly, its just that the mode-line doesn't update when moving the point

I tried doing the following

(add-hook 'move-beginning-of-line 'force-mode-line-update)
(add-hook 'move-end-of-line 'force-mode-line-update)
(add-hook 'forward-char 'force-mode-line-update)
(add-hook 'backward-char 'force-mode-line-update)
(add-hook 'next-line 'force-mode-line-update)
(add-hook 'previous-line 'force-mode-line-update)

But it still doesn't update

Any suggestions?

Code:

(setq-default mode-line-format 
 (list

  "---- "    

  ;; Modified shows *      
  "[" 
  '(:eval 
(if (buffer-modified-p) 
    "*"
    (if buffer-read-only
    "!"
    " "
    )))
  "] "

  ;; Buffer (tooltip - file name)
  '(:eval (propertize "%b" 'face 'bold 'help-echo (buffer-file-name)))


  " "

  ;; Spaces 12 - "buffer"
  '(:eval
    (make-string
     (- 12
  (min
     12
     (length (buffer-name))))
    ?-))

" "
  ;; Current (row,column)
  "(" '(:eval (number-to-string (count-lines 1 (point)))) 
  "," '(:eval (number-to-string (current-column))) 
  ") "

  ;; Spaces 7 - "(r,c)"
  '(:eval
    (make-string
     (- 7
  (min
     4
     (length (number-to-string (current-column)))
  ) 
  (min
     3
     (length (number-to-string (1+ (count-lines 1 (point)))))))
    ?-))

  ;; Percentage of file traversed (current line/total lines)
  " [" 
  '(:eval (number-to-string (/ (* (1+ (count-lines 1 (point))) 100) (count-lines 1 (point-max)))) )
  "%%] "

  ;; Spaces 3 - %
  '(:eval 
    (make-string
     (- 3 (length (number-to-string (/ (* (1+ (count-lines 1 (point))) 100) (count-lines 1 (point-max))))))
    ?-))

  ;; Major Mode
  " [" '(:eval mode-name) "] "

  ;; Spaces 16 + (6 - %)
  '(:eval
    (make-string
     (- 22
  (min
     6
     (length mode-name)))
    ?-))

  " ("

  ;; Time
  '(:eval (format-time-string "%H:%M"))

  ;; Fill with '-'
  ") %-" 
 ))

Thanks in advance

What information are you trying to put in the mode line? It's difficult to answer the question without know what you are trying to do. — scottfrazer, Dec 05 '11 at 14:47
@Yuuta functions are supposed to be advised if needed. and also functions can be added to hooks with `add-hook` again if needed. — kindahero, Dec 05 '11 at 17:44
@scottfrazer I added the code in the question. But I'm adding information about the buffer to see if its modified or read only, current column/line, buffer name, how far from the top of the page I am, major mode and time. — Yuuta, Dec 05 '11 at 18:01
@kindahero I'm looking up advised functions, thanks for the information ^^ — Yuuta, Dec 05 '11 at 18:01
Tangentially, does your school realise they are providing such an old version of Emacs? Perhaps you could get them to update it. — phils, Dec 05 '11 at 21:12
@phils They use Fedora/Red hat and for some reason that's the latest version of emacs they currently support =/ — Yuuta, Dec 05 '11 at 21:36

Dale Hagglund · Answer 1 · 2011-12-15T06:23:36.473

In the comments on the original post, you mention the following information you'd like in the mode line:

modified or read only
column / line number
buffer name
how far from the top of the page I am
major mode
current time

I've used emacs forever and all of (1), (3), and (5) are in the default emacs mode line for every buffer already, and have been for a very long time. To enable (2) and (6), add

(display-time-mode 1)
(setq line-number-mode t)
(setq column-number-mode t)

to ~/.emacs. From what I can find online, column-number-mode postdates emacs 21.

Note that none of this requires explicitly redefining mode-line, overriding any functions, or adding any hooks. I haven't provided an answer for (4) because I don't know what you mean by it.

Emacs - Mode Line Update

1 Answers1