AUCTeX: Disable newline when electric-pairing braces in math mode

Question

I am using AUCTeX for editing in LaTeX, with LaTeX-electric-left-right-brace enabled, so that when I press for example C-c C-m \left in a math environment, the right brace is also automatically put in my expression.

My problem is that this automatically inserts a newline after the left brace and before the right brace, so that it looks like this for example:

\left(

\right)

with the point inserted in the middle. But I don't want that. I couldn't find anything about it in the Info documentation. Could anyone please tell me how to disable this behavior? (i.e. have the same but on one single line)

Answer 1

Thanks to arash-esbati's findings it is quite easy to deactivate LaTeX-newline locally within TeX-arg-insert-braces through advices.

Install the following code into your init file and TeX-arg-insert-braces does no longer generate newlines.

;; The following macro should actually be part of package `advice`:
(defmacro advise-flet (flist &rest body)
  "Apply local advices FLIST and execute BODY.
Each advice in FLIST should look like (FUN DEF)
where FUN is a function symbol and DEF is the
locally defined function."
  (declare (indent 1) (debug (sexp body)))
  (append
   `(unwind-protect
    (progn
      ,(cons 'progn
         (cl-loop
          for f in flist
          collect `(advice-add ,(list 'quote (car f)) :override ,(cadr f))
          ))
      ,@body))
   (cl-loop
    for f in flist
    collect `(advice-remove ,(list 'quote (car f)) ,(cadr f))
    )))

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Begin of customization code:

(defun LaTeX-without-newline (oldfun &rest args)
  "`flet' `LaTeX-newline' to `ignore' and run `TeX-arg-insert-braces'."
  (advise-flet
      ((LaTeX-newline #'ignore))
    (apply oldfun args)))

(advice-add #'TeX-arg-insert-braces :around #'LaTeX-without-newline)

Answer 2

I'm afraid this behavior is hard-coded in the function TeX-arg-insert-braces and cannot be disabled (besides overwriting or better advising). As a quick fix, I suggest you take the current behavior, insert your math and hit M-q. It turns

$
\left(
  math and hit M-q
\right)$

into

$ \left( math and hit M-q \right)$