I want to change the name of the function key <mouse-1> like so:
(define-key input-decode-map (kbd "<mouse-1>") (kbd "<jd:m1>"))

And thus bind the new name to an arbitrary function like so:
(define-key global-map (kbd "<jd:m1>") 'mouse-set-point)

But when testing the changes I get this error:

Debugger entered--Lisp error: (error "mouse-set-point must be bound to an event with parameters")
  call-interactively(mouse-set-point nil nil)

Why does this functionality work for all other key functions but not the mouse key functions?

For example this works just fine:

(define-key input-decode-map (kbd "<tab>") (kbd "<jd:tab>"))
(define-key global-map (kbd "<jd:tab>") 'indent-for-tab-command)

1 Answer 1


The issue is the following:

(define-key input-decode-map [mouse-1] [jd:m1])

will convert any incoming "event with name mouse-1" into the event jd:m1, whereas you want to convert it to a similar "event with name jd:m1". More specifically, mouse events are not just symbols but have the form:


where NAME may be equal to things like mouse-1 and METADATA holds info such as the location where the user pressed this mouse button.

IOW, your remapping turns (mouse-1 . METADATA) into a "dumb" jd:m1 losing the METADATA along the way.

Doing the kind of remapping you propose is actually tricky for all kinds of arbitrary reasons. I suggest you look at the source code of mouse--click-1-maybe-follows-link to see what it might involve.

Basically, you'll need something like:

(define-key input-decode-map [mouse-1]
  (lambda (&optional _prompt)
    (let ((newname 'jd:m1))
      ;; Copy the `event-kind` at the first occasion.
      (unless (get newname 'event-kind)
        (put newname 'event-kind
             (get (car last-input-event) 'event-kind)))
      ;; Modify the event in-place, otherwise we can get a prefix
      ;; added again, so a click on the header-line turns
      ;; into a [header-line header-line <newname>] :-(.
      ;; See fake_prefixed_keys in src/keyboard.c's.
      (setf (car last-input-event) newname)
      (vector last-input-event))))


  • 1
    So I'm assuming that the events <vertical-line> and <mode-line> both have metadata associated with them as well? When events like, <escape>, <return>, and <tab>, etc. are dummy events with only a key press that's associated with them..? Or I guess a better follow up question would be how in the world you found out that the <mouse-1> event has the form (NAME . METADATA)?? I can't M-x describe that or anything, and I wouldn't know where to start to find information like that. Commented Sep 14, 2018 at 22:02
  • 1
    @JohnDeBord: Actually, I think that those pseudo events like mode-line and vertical-line don't carry any metadata. You can figure it out by looking at the shape of the value of last-input-event during the remapping, but for that you need to use a function like I did (IOW, you already need to know more than you originally did).
    – Stefan
    Commented Sep 14, 2018 at 22:50
  • Ok. Well it just dawned on me...How in the heck do I just rename this fricken symbol (or symbols) without going through all the hassle of converting the events. I don't care if I have to modify the source code or anything. I've gone down this rabbit hole for far too long and I just need something to show for it. Commented Sep 14, 2018 at 22:58
  • Really would appreciate a quick response. This is going to be my project for the night. But I understand if you're busy. Commented Sep 15, 2018 at 1:43
  • @JohnDeBord: response to what question?
    – Stefan
    Commented Sep 15, 2018 at 2:07

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