Is there a variable to toggle Emacs 24.4 elisp return "noise"?

Question

In Emacs 24.4, every time I evaluate a form in ielm or using C-x C-e it prints a lot of extraneous output that while useful, sometimes gets in the way. As an example,

(+ 1 1)
;=> 2 (#o2, #x2, ?\C-b)

Is there a variable I can use to disable printing this extra information and have it just display 2 like it used to?

I mean C-x C-e and *ielm*. I'm not aware of a single way of evaluating elisp that doesn't return this extra information by default. — wdkrnls, Nov 20 '14 at 00:29
@wdkrnls, `C-j` in `*scratch*` shows no extra info, also `e` in https://github.com/abo-abo/lispy. — abo-abo, Nov 20 '14 at 10:12
The extra information only appears in the echo area. If you evaluate with `C-u C-x C-e` to get the output in the current buffer, it does not appear. Isn't that what you do if you wish to insert the result somewhere? — Harald Hanche-Olsen, Nov 20 '14 at 16:35
@HaraldHanche-Olsen IIUC, he doesn't want to insert it anywhere, he just finds this extra information in the echo area unhelpful and wants to hide it. — Malabarba, Nov 21 '14 at 00:34

score 4 · Answer 1 · edited Apr 13 '17 at 12:52

4

You can override eval-expression-print-format to return "" or nil:

(defun eval-expression-print-format (value)
  ; return an empty string
  "")

See the answer by @Harald Hanche-Olsen for a way to override it temporarily.

edited Apr 13 '17 at 12:52

Community

1

answered Nov 20 '14 at 00:19

Constantine

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It's a fine solution, but I'd hardly use the word “temporarily” to describe it. A bit of advice is in order (pun intended); see my answer. – Harald Hanche-Olsen Nov 21 '14 at 07:37
@HaraldHanche-Olsen: Fair enough. :-) I'll remove "temporarily" from my answer. – Constantine Nov 21 '14 at 17:44

score 3 · Accepted Answer · answered Nov 21 '14 at 07:35

3

If you don't want a permanent change, you can arrange things with a bit of advice:

(defvar mute-eval-expression-print-format nil
  "Set to t to mute eval-expression-print-format")
(defun mute-eval-expression-print-format (orig-fun value)
  (if mute-eval-expression-print-format
      ""
    (funcall orig-fun value)))
(advice-add 'eval-expression-print-format
        :around #'mute-eval-expression-print-format)

Now set mute-eval-expression-print-format to t in order to mute the extra output.

Note that this uses the new advice mechanism (introduced with emacs 24, I think).

answered Nov 21 '14 at 07:35

Harald Hanche-Olsen

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Well OP explicitly mentioned emacs 24.4 so it should be good ;-) – syl20bnr Nov 21 '14 at 19:30
1

@syl20bnr Indeed, but the comment could be useful to others that aren't so up to date. – Harald Hanche-Olsen Nov 21 '14 at 20:19

Is there a variable to toggle Emacs 24.4 elisp return "noise"?

2 Answers2