Two key shortcut in emacs without repressing the first key?

Question

Suppose I define the following shortcut

(global-set-key (kbd "C-d C-j") "Hello!")

Is it possible to configure emacs so that if I type "C-d C-j C-j C-j" I will get "Hello! Hello! Hello!" rather than having to type "C-d C-j C-d C-j C-d C-j"?

Answer 1

I don’t think you can configure Emacs so that it does that for all commands. However, you can implement this functionality in the commands themselves. This is what is done for C-x e. Here is a macro I just wrote (guided by the standard definition of kmacro-call-macro in GNU Emacs 23.1.1) that makes it easy to add this functionality to your own commands:

(defmacro with-easy-repeat (&rest body)
  "Execute BODY and repeat while the user presses the last key."
  (declare (indent 0))
  `(let* ((repeat-key (and (> (length (this-single-command-keys)) 1)
                           last-input-event))
          (repeat-key-str (format-kbd-macro (vector repeat-key) nil)))
     ,@body
     (while repeat-key
       (message "(Type %s to repeat)" repeat-key-str)
       (let ((event (read-event)))
         (clear-this-command-keys t)
         (if (equal event repeat-key)
             (progn ,@body
                    (setq last-input-event nil))
           (setq repeat-key nil)
           (push last-input-event unread-command-events))))))

Here’s how you use it:

(defun hello-world ()
  (interactive)
  (with-easy-repeat
    (insert "Hello, World!\n")))

(global-set-key (kbd "C-c x y z") 'hello-world)

Now you can type C-c x y z z z to insert Hello, World! three times.