Smart minor mode toggle depending on major mode

Question

I use several minor modes, which are enabled globally by default:

• whitespace-mode
• linum-mode
• fci-mode

I'm finding them very helpful when editing code sources and text files, however I does not want to activate them with some major modes, e.g. dired-mode, eshell.

I've tried to solve this as following:

(add-hook 'prog-mode-hook '(linum-mode 1))

(require 'whitespace)
(add-hook 'prog-mode-hook '(whitespace-mode 1))

(require 'fill-column-indicator)
(add-hook 'prog-mode-hook '(fci-mode 1))
(add-hook 'text-mode-hook '(fci-mode 1))

But this solution does not works well:

• reverting buffer toggles off linum-mode
• whitespace-mode not activating
• fci-mode not activating, producing error message

  File mode specification error: (invalid-function (fci-mode 1)) [2 times]

What is the correct way to make smart toggle mentioned modes only with source code buffers and text buffers?

P.S. A note about fci-mode: error message looks odd to me, because I can either use M-x fci-mode to toggle it, or evaluate (fci-mode 1) or (fci-mode -1).

Answer 1

In Emacs 23 (some-mode 1) was the typical way to turn on minor modes (but see this answer for the proper way to add them to the hooks). But Emacs 24 changed the rules for turning on minor modes. The argument to mode functions is no longer needed to turn the mode on anymore:

Toggle display of line numbers in the left margin (Linum mode). With a prefix argument ARG, enable Linum mode if ARG is positive, and disable it otherwise. If called from Lisp, enable the mode if ARG is omitted or nil.

So to simply turn on a minor mode, what you want is just #'linum-mode in your hooks.

Answer 2

A hook expects its entries to be functions. (fci-mode 1) is not a function.

What you want to use as a function is presumably turn-on-fci-mode, if that function exists, or (lambda () (fci-mode 1)), if not.

See the Elisp manual, node Defining Minor Modes, particularly macro define-globalized-minor-mode.

You give no references for the global-mode functions you cite, so I don't know how they were defined. But if they were defined using define-globalized-minor-mode then there is likely a TURN-ON function that you can use on a hook.