Emacs/Auctex: Automatically enabling/disabling LaTeX-Math-mode

Question

I'm using Emacs in conjunction with AucTeX (running Ubuntu 10.04, if that matters).

Does anyone know if there is a way to automatically enable LaTeX-math-mode (a minor mode of AucTeX) if the point is in any maths environment (i.e. in a $...$, a $$...$$, begin{equation}...\end{equation}, and so on)?

I suppose there is a relatively easy answer, since syntax highlighting uses the same criterion for coloring math stuff, but I could not find anything.

Answer 1

If andre-r's answer doesn't satisfy you, here's some code that sets up ` to self-insert in text mode and act as a math mode prefix in math mode. LaTeX-math-mode must be off.

(defun LaTeX-maybe-math ()
  "If in math mode, act as a prefix key for `LaTeX-math-keymap'.
Otherwise act as `self-insert-command'."
  (interactive)
  (if (texmathp)
      (let* ((events (let ((overriding-local-map LaTeX-math-keymap))
                       (read-key-sequence "math: ")))
             (binding (lookup-key LaTeX-math-keymap events)))
        (call-interactively binding))
    (call-interactively 'self-insert-command)))
(define-key LaTeX-mode-map "`" 'LaTeX-maybe-math)

The following improvements are left as exercises:

• Make it a minor mode.

• Make it more robust towards unexpected input (I've only tested basic operation).

• Show a better error message if the user presses an unbound key sequence.

• Show help if the user presses C-h or f1.

Answer 2

LaTeX-math-mode is "a special minor mode for entering text with many mathematical symbols." (For those who don't know how, you press e.g. `A and get \forall.) So I guess it doesn't hurt to leave it on, also if you're not entering maths.

The info page therefore suggests:

(add-hook 'LaTeX-mode-hook 'LaTeX-math-mode)

IMHO the only downside would be that you have to press the prefix twice: `` to get `, at least that works with the standard prefix ` customized in LaTeX-math-abbrev-prefix.