whitespace busters for Emacs

a-part-of-dot-emacs.el

(defvar undesirable-ws-cleanup-wo-choice-modes
  '(lisp-mode))

(defvar undesirable-ws-cleanup-w-check-modes
  '(org-mode))

(defun undesirable-ws-cleanup ()
  (interactive)
  (save-excursion
    (when (or (member major-mode undesirable-ws-cleanup-wo-choice-modes)
	      (and (member major-mode undesirable-ws-cleanup-w-check-modes)
		   (y-or-n-p "Really untabify/delete-trailing-whitespace ? ")))
      (untabify (point-min) (point-max))
      (delete-trailing-whitespace (point-min) (point-max))))
  nil)

(add-hook 'before-save-hook 'undesirable-ws-cleanup)