How to automatically wrap long lines in emacs?

Question

I just tried Gnu emacs 23 automatic long line wrapping feature using M-x auto-fill-mode. it works perfectly. Now I modified my .emacs file as following to have this feature always turned on but it doesn't work ...

;;; Xemacs backwards compatibility file
(setq user-init-file
      (expand-file-name "init.el"
            (expand-file-name ".xemacs" "~")))
(setq custom-file
      (expand-file-name "custom.el"
            (expand-file-name ".xemacs" "~")))

(load-file user-init-file)
(load-file custom-file)
(global-linum-mode t)

;;; Scrollbar on the right
(set-scroll-bar-mode 'right)

;;; Open help file
(find-file "/home/manu/These/Docs/Emacs-Shortcuts")
(split-window-horizontally)

;;; Transparency
 ;;(set-frame-parameter (selected-frame) 'alpha '(<active> [<inactive>]))
 (set-frame-parameter (selected-frame) 'alpha '(85 50))
 (add-to-list 'default-frame-alist '(alpha 85 50))

;;; Auto fill to wrap long lines
(add-hook 'text-mode-hook 'turn-on-auto-fill)

Where am I wrong ?

Answer 1

According to Emacs FAQ you can turn on auto-fill mode just for text-mode (for general text files)

(add-hook 'text-mode-hook 'turn-on-auto-fill)

If you want to enable auto-fill mode globally (for all modes) add this line to your ini file:

(setq-default auto-fill-function 'do-auto-fill)

Answer 2

Emacs 23 has visual-line-mode, which does not change the text, but instead wraps long lines on word boundaries when the buffer is displayed. For some kinds of document this is better than auto-fill-mode, which changes the text, and so loses the distinction between "soft" and "hard" line breaks.

You can automatically turn on visual-line-mode in the same way as auto-fill-mode, for example:

(add-hook 'text-mode-hook 'turn-on-visual-line-mode)