How can I make backward-kill-word stop at special character such as paratheses and line breaks?

Question

Is it possible to change the behavior of backward-kill-word (bound to M-DEL by default) to stop at special characters? Quite often it deletes parentheses and line breaks against my will.

Answer 1

That command uses forward/backward word internally, i.e. it finds the next word in buffer if not within - and deletes region between. From there it's rather difficult to tweak.Try this:

(defun my-backward-kill-word ()
  (interactive "*")
  (let ((orig (point)))
    (skip-syntax-backward "\sw")
    (delete-region (point) orig)))

Answer 2

I did it like this:

(defun dwim-backward-kill-word ()
  "DWIM kill characters backward until encountering the beginning of a
word or non-word."
  (interactive)
  (if (thing-at-point 'word) (backward-kill-word 1)
    (let* ((orig-point              (point))
           (orig-line               (line-number-at-pos))
           (backward-word-point     (progn (backward-word) (point)))
           (backward-non-word-point (progn (goto-char orig-point) (backward-non-word) (point)))
           (min-point               (max backward-word-point backward-non-word-point)))

      (if (< (line-number-at-pos min-point) orig-line) (progn (goto-char min-point) (end-of-line) (delete-horizontal-space))
        (delete-region min-point orig-point)
        (goto-char min-point))
      )))

(defun backward-non-word ()
  "Move backward until encountering the beginning of a non-word."
  (interactive)
  (search-backward-regexp "[^a-zA-Z0-9\s\n]")
  (while (looking-at "[^a-zA-Z0-9\s\n]")
    (backward-char))
  (forward-char))