Vim-style increment/decrement numbers under the cursor, for Emacs.

inc-number.el

;; vim-style increment/decrement numbers
(defun inc-number-at-point (n)
  "Increment the number under the point, if present.
Called with a prefix argument, changes the number by N."
  (interactive "p")
  (let ((amt (or n 1))
        (word (thing-at-point 'word))
        (bounds (bounds-of-thing-at-point 'word)))
    (when (string-match "^[0-9]+$" word)
      (replace-string word
                      (format "%d" (+ amt (string-to-int word)))
                      nil (car bounds) (cdr bounds))
      (forward-char -1))))