Add a TeX symbol in the Emacs init file

Question

I am trying to add the following code to my .emacs init file:

(TeX-add-symbols '("eqref" TeX-arg-ref))

But I cannot get it to work. I get the following error when running emacs t.tex (t.tex is here a sample text file) from the command line:

Warning (initialization): An error occurred while loading `.emacs':
Symbol's function definition is void: TeX-add-symbols

I am using GNU Emacs version 23.3.1 on Ubuntu 12.04. My .emacs init file looks like

(setq TeX-auto-parse t)
(setq TeX-electric-escape t)
(setq reftex-label-alist '((nil ?e nil "~\\eqref{%s}" nil nil)))
(add-hook 'LaTeX-mode-hook 'turn-on-reftex)
(setq reftex-plug-into-AUCTeX t)
(TeX-add-symbols '("eqref" TeX-arg-ref))

If I enter ESC-: (i.e. running the command eval-expression) and enter (TeX-add-symbols '("eqref" TeX-arg-ref)) at the prompt it works fine. (That is after running this, I can enter \eqref in the buffer and it works as expected.. But this is not a good solution, having to enter this code manually each time I edit a file.. That is the reason why I try to set it up in the .emacs file..)

Background information for this question:

I have a problem with using the AucTeX style amsmath.el.. it seems that it is not loaded properly on my machine.. For more information, see Using \eqref with RefTeX.

Answer 1

You have to evaluate the code after LaTeX-mode is activated, otherwise you get the error Symbol's function definition is void: TeX-add-symbols. You can add that function to the hook of LaTeX-mode. In order to override possible other eqref macro definitions, you should add a dummy (ignore) to the definition of the macro. This code, in your .emacs, does the trick:

(add-hook 'LaTeX-mode-hook
      '(lambda ()
         (TeX-add-symbols '("eqref" TeX-arg-ref (ignore)))))