For some reason, emacs functions which use the interactive form don't work for me on Mac OS x. The emacs I am using is from emacsformacosx.com, which up until now has worked flawlessly. An example of such a function that uses interactive (taken from here) is:

(defun multiply-by-seven (number)       ; Interactive version.
   "Multiply NUMBER by seven."
   (interactive "p")
   (message "The result is %d" (* 7 number)))

I run it in scratch with C-x C-e, but I'm not able to enter a number and get anything out.

  • How are you attempting to enter the number? What is the error you're getting? – Darren Hall Jan 6 '10 at 2:28

I am a little worried by:

I run it in scratch with C-x C-e

This does not run the function, it just evaluates it. To call the function you can evaluate:

(multiply-by-seven 10)
  => "The result is 70"

with C-x C-e or call it interactivly:

M-x multiply-by-seven
  => "The result is 7"

and call it with an argument

C-u M-x multiply-by-seven
  => "The result is 28"


C-u 7 M-x multiply-by-seven
  => "The result is 49"

as (interactive "p") uses the numeric prefix argument, Emacs Manual

  • +1 for "This does not run the function, it just evaluates it." – Doug Harris Jan 6 '10 at 19:39
  • +1 Yup, I noticed this myself after digging in a bit more. My emacs fu is very weak. Thanks for the comprehensive answer. – Rob Jan 7 '10 at 6:26

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.