Delete a word without adding it to the kill-ring in Emacs

Question

When switching files using the minibuffer (C-x C-f), I often use M-Backspace to delete words in the path. Emacs automatically places what I delete into the kill ring. This can be annoying, as sometime I am moving to another file to paste something, and I end up pasting part of the file path. I know there are workarounds, and the other code is still in the kill ring, etc, but I would just like to disable this functionality.

Answer 1

Emacs doesn't have a backward-delete-word function, but it's easy enough to define one:

(defun backward-delete-word (arg)
  "Delete characters backward until encountering the beginning of a word.
With argument ARG, do this that many times."
  (interactive "p")
  (delete-region (point) (progn (backward-word arg) (point))))

Then you can bind M-Backspace to backward-delete-word in minibuffer-local-map:

(define-key minibuffer-local-map [M-backspace] 'backward-delete-word)

Answer 2

See a discussion of this topic at help-gnu-emacs@gnu.org: http://lists.gnu.org/archive/html/help-gnu-emacs/2011-10/msg00277.html

The discussion boils down to this short solution:

(add-hook 'minibuffer-setup-hook'
          (lambda ()
            (make-local-variable 'kill-ring)))