Info Catalog elisp: Mode Line Data elisp: Mode Line Format elisp: Mode Line Variables

elisp: Mode Line Top

 
 22.4.3 The Top Level of Mode Line Control
 -----------------------------------------
 
 The variable in overall control of the mode line is ‘mode-line-format’.
 
  -- User Option: mode-line-format
      The value of this variable is a mode line construct that controls
      the contents of the mode-line.  It is always buffer-local in all
      buffers.
 
      If you set this variable to ‘nil’ in a buffer, that buffer does not
      have a mode line.  (A window that is just one line tall also does
      not display a mode line.)
 
    The default value of ‘mode-line-format’ is designed to use the values
 of other variables such as ‘mode-line-position’ and ‘mode-line-modes’
 (which in turn incorporates the values of the variables ‘mode-name’ and
 ‘minor-mode-alist’).  Very few modes need to alter ‘mode-line-format’
 itself.  For most purposes, it is sufficient to alter some of the
 variables that ‘mode-line-format’ either directly or indirectly refers
 to.
 
    If you do alter ‘mode-line-format’ itself, the new value should use
 the same variables that appear in the default value (Mode Line
 Variables), rather than duplicating their contents or displaying the
 information in another fashion.  This way, customizations made by the
 user or by Lisp programs (such as ‘display-time’ and major modes) via
 changes to those variables remain effective.
 
    Here is a hypothetical example of a ‘mode-line-format’ that might be
 useful for Shell mode (in reality, Shell mode does not set
 ‘mode-line-format’):
 
      (setq mode-line-format
        (list "-"
         'mode-line-mule-info
         'mode-line-modified
         'mode-line-frame-identification
         "%b--"
         ;; Note that this is evaluated while making the list.
         ;; It makes a mode line construct which is just a string.
         (getenv "HOST")
         ":"
         'default-directory
         "   "
         'global-mode-string
         "   %[("
         '(:eval (mode-line-mode-name))
         'mode-line-process
         'minor-mode-alist
         "%n"
         ")%]--"
         '(which-func-mode ("" which-func-format "--"))
         '(line-number-mode "L%l--")
         '(column-number-mode "C%c--")
         '(-3 "%p")))
 
 (The variables ‘line-number-mode’, ‘column-number-mode’ and
 ‘which-func-mode’ enable particular minor modes; as usual, these
 variable names are also the minor mode command names.)
 

Info Catalog elisp: Mode Line Data elisp: Mode Line Format elisp: Mode Line Variables