Fix bug with protecting LaTeX macros

The regular expression was not optimal, and if there was a horizontal
rule, search would not start from the beginning of the buffer but from
after the rule!

lisp/ChangeLog

@@ -1,5 +1,10 @@
 2009-12-16  Carsten Dominik  <carsten.dominik@gmail.com>
 
+	* org-latex.el (org-export-latex-preprocess): Better version of
+	the regular expression for protecting LaTeX macros.
+	(org-export-latex-preprocess): Start searching for macros to
+	protect from beginning of buffer.
+
 	* org-exp.el (org-export-target-internal-links): Check for
 	protectedness earlier in the string.
 

lisp/org-latex.el

@@ -1877,11 +1877,11 @@ The conversion is made depending of STRING-BEFORE and STRING-AFTER."
      (replace-match (org-export-latex-protect-string "\\hrule") t t)))
 
   ;; Protect LaTeX commands like \command[...]{...} or \command{...}
-  (let ((re (concat "\\\\[a-zA-Z]+\\(?:"
-		    "\\[.*\\]"
-		    "\\)?"
-		    "\\(" (org-create-multibrace-regexp "{" "}" 3)
-		    "\\)\\{1,3\\}")))
+  (goto-char (point-min))
+  (let ((re (concat
+	     "\\\\[a-zA-Z]+"
+	     "\\(?:\\[[^][\n]*?\\]\\)*"
+	     "\\(" (org-create-multibrace-regexp "{" "}" 3) "\\)\\{1,3\\}")))
     (while (re-search-forward re nil t)
       (unless (save-excursion (goto-char (match-beginning 0))
 			      (equal (char-after (point-at-bol)) ?#))