When writing tex documents, I often create and include a file that contains a number of user defined macros, e.g., \newcommand{\pstar}{\ensuremath{\mathcal{P}^\star}}.

I'd like to set up emacs syntax highlighting so that every time I use one of my user defined macros, e.g., \pstar, the macro is highlighted in a default color. How can I do this without having to specify a list of my macros up front (as in this answer)?

  • You are abusing \ensuremath. See When not to use \ensuremath for math macro? – Henri Menke Aug 30 '18 at 5:20
  • You will have to specify a list of macros. Otherwise you'd have to implement a LaTeX parser in Lisp which scans the whole document and any \included files for command definitions. – Henri Menke Aug 30 '18 at 5:23
  • Thanks @HenriMenke. Before I started using auctex, I had the syntax highlighting I wanted (although, I didn't have a lot of other things I wanted). But, I'm actually not sure what tool was providing the highlight :). Perhaps it was the oh-my-zsh template I am using. Maybe there is another easy way to highlight expressions that start with a backslash in a default color when in latex mode (unless they are known keywords that already have a specific highlighting pattern). – akobre01 Aug 30 '18 at 13:16

It is possible to do what you're asking for, but I'm not recommending it. Hence, I show 2 solutions:

Not recommended solution

I presume you're not byte-compiling your init file. Put this function somewhere in your init file:

(defun LaTeX-fontify-parsed-macros ()
  "Add fontification support for parsed macros by AUCTeX."
  (let ((TeX-grop-string (string-to-char TeX-grop))
        macs macname args)
    ;; Process elements from `LaTeX-auto-optional' which look like
    ;; ("PSTAR" "1" "x")
    (dolist (mac LaTeX-auto-optional)
      (setq macname (car mac)
            args (string-to-number (cadr mac)))
      (push (list macname (concat LaTeX-optop
                                  (make-string (1- args)
    ;; Process elements from `LaTeX-auto-arguments' which look like
    ;; ("PStar" "1")
    (dolist (mac LaTeX-auto-arguments)
      (setq macname (car mac)
            args (string-to-number (cadr mac)))
      (push (list macname (make-string args TeX-grop-string))
    ;; Process only string elements from `TeX-auto-symbol' and ignore
    ;; lists inside the list
    (dolist (mac TeX-auto-symbol)
      (unless (listp mac)
        (push (list mac "") macs)))
    ;; Fontify the macros:
    (when (and macs
               (featurep 'font-latex)
               (eq TeX-install-font-lock 'font-latex-setup))
      (font-latex-add-keywords macs
                               'textual)) ))

Now in your .tex file, add this line to your file local variables at the end of the file:

%%% eval: (add-hook 'TeX-update-style-hook #'LaTeX-fontify-parsed-macros t)

It should look like this:

%%% Local Variables:
%%% mode: latex
%%% TeX-master: t
%%% eval: (add-hook 'TeX-update-style-hook #'LaTeX-fontify-parsed-macros t)
%%% End:

Now hit C-c C-n, and you should get proper fontification for your macros.

Recommended solution

Move your definitions into a separate package, say mymathmacros.sty which looks like this:




Customize the variable TeX-style-private to a directory of your choice, e.g. with a line like this in your init file:

(setq TeX-style-private (expand-file-name "~/.emacs.d/my-auctex-styles/"))

Save this piece of code in that directory as mymathmacros.el:

 (lambda ()
   ;; Macros:
    '("pstar" 0)
    '("Pstar" 0)
    '("PStar"  1)
    '("PSTar" [ "argument" ] 1)
    '("PSTAR" [ "argument" ] 2))

   ;; Fontification:
   (when (and (featurep 'font-latex)
              (eq TeX-install-font-lock 'font-latex-setup))
     (font-lock-add-keywords '(("pstar" "")
                               ("Pstar" "")
                               ("PStar" "{")
                               ("PSTar" "[{")
                               ("PSTAR" "[{{"))

Restart your Emacs, add the line \usepackage{mymathmacros} to your .tex file and hit C-c C-n, if necessary.

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