Emacs: Key Macro Example: Eval Emacs Lisp Repeatedly

By Xah Lee. Date: . Last updated: .

Here's another example of Emacs: Keyboard Macro use.

I have a function insert-random-uuid [see Emacs: Insert Random UUID 🚀] I want to call it hundreds of times to see its output. Let's just say i want to call the elisp expression (random 100) one hundred times.

One way is to write a elisp command on the spot, like this:

(defun xx-random-test ()
  (dotimes (ii 100) (insert (format "%d " (random 100))))

But that takes 5 minutes to write, plus you need to have elisp knowledge. You can use a kmacro to do this fast, with the following steps.

  1. Start kmacro Ctrl+x (.
  2. Type Ctrl+u, then Alt+x eval-expression, with this expression (random 100). The Ctrl+u will make eval-expression insert its result in current buffer.
  3. Type a space.
  4. End kmacro Ctrl+x ).
  5. Type Ctrl+u 100 then call kmacro-end-and-call-macroCtrl+x e】.

Emacs Keyboard Macro