Insert a customizable separator between footnotes

* lisp/org-docbook.el (org-export-docbook-footnote-separator): new
  variable
  (org-export-as-docbook): add a separator between footnotes.
* lisp/org-html.el (org-export-html-footnote-separator): new variable.
  (org-export-as-html): add a separator between footnotes.
* lisp/org-latex.el (org-export-latex-footnote-separator): new
  variable.
  (org-export-latex-preprocess): add a separator between footnotes.

lisp/org-docbook.el

@@ -148,6 +148,11 @@ avoid same set of footnote IDs being used multiple times."
   :group 'org-export-docbook
   :type 'string)
 
+(defcustom org-export-docbook-footnote-separator "<superscript>, </superscript>"
+  "Text used to separate footnotes."
+  :group 'org-export-docbook
+  :type 'string)
+
 (defcustom org-export-docbook-emphasis-alist
   `(("*" "<emphasis role=\"bold\">" "</emphasis>")
     ("/" "<emphasis>" "</emphasis>")
@@ -942,14 +947,22 @@ publishing directory."
 					  org-export-docbook-footnote-id-prefix num)
 				  t t line))
 		    (setq line (replace-match
-				(format "%s<footnote xml:id=\"%s%s\"><para>%s</para></footnote>"
-					(match-string 1 line)
-					org-export-docbook-footnote-id-prefix
-					num
-					(if footnote-def
-					    (save-match-data
-					      (org-docbook-expand (cdr footnote-def)))
-					  (format "FOOTNOTE DEFINITION NOT FOUND: %s" num)))
+				(concat
+				 (format "%s<footnote xml:id=\"%s%s\"><para>%s</para></footnote>"
+					 (match-string 1 line)
+					 org-export-docbook-footnote-id-prefix
+					 num
+					 (if footnote-def
+					     (save-match-data
+					       (org-docbook-expand (cdr footnote-def)))
+					   (format "FOOTNOTE DEFINITION NOT FOUND: %s" num)))
+				 ;; If another footnote is following the
+				 ;; current one, add a separator.
+				 (if (save-match-data
+				       (string-match "\\`\\[[0-9]+\\]"
+						     (substring line (match-end 0))))
+				     org-export-docbook-footnote-separator
+				   ""))
 				t t line))
 		    (push (cons num 1) footref-seen))))))
 

lisp/org-html.el

@@ -60,6 +60,12 @@ by the footnotes themselves."
   :group 'org-export-html
   :type 'string)
 
+
+(defcustom org-export-html-footnote-separator "<sup>, </sup>"
+  "Text used to separate footnotes."
+  :group 'org-export-html
+  :type 'string)
+
 (defcustom org-export-html-coding-system nil
   "Coding system for HTML export, defaults to `buffer-file-coding-system'."
   :group 'org-export-html
@@ -1587,11 +1593,19 @@ lang=\"%s\" xml:lang=\"%s\">
 		    (push (cons n 1) footref-seen))
 		  (setq line
 			(replace-match
-			 (format
-			  (concat "%s"
-			 	  (format org-export-html-footnote-format
-			 		  "<a class=\"footref\" name=\"fnr.%s%s\" href=\"#fn.%s\">%s</a>"))
-			  (or (match-string 1 line) "") n extra n n)
+			 (concat
+			  (format
+			   (concat "%s"
+				   (format org-export-html-footnote-format
+					   (concat "<a class=\"footref\" name=\"fnr.%s%s\" href=\"#fn.%s\">%s</a>")))
+			   (or (match-string 1 line) "") n extra n n)
+			  ;; If another footnote is following the
+			  ;; current one, add a separator.
+			  (if (save-match-data
+				(string-match "\\`\\[[0-9]+\\]"
+					      (substring line (match-end 0))))
+			      org-export-html-footnote-separator
+			    ""))
 			 t t line))))))
 
 	  (cond

lisp/org-latex.el

@@ -311,6 +311,11 @@ will be filled with the link, the second with its description."
   :group 'org-export-latex
   :type 'string)
 
+(defcustom org-export-latex-footnote-separator "\\textsuperscript{,}\\,"
+  "Text used to separate footnotes."
+  :group 'org-export-latex
+  :type 'string)
+
 (defcustom org-export-latex-tables-verbatim nil
   "When non-nil, tables are exported verbatim."
   :group 'org-export-latex
@@ -2420,7 +2425,7 @@ The conversion is made depending of STRING-BEFORE and STRING-AFTER."
   ;; When converting to LaTeX, replace footnotes.
   (when (plist-get opt-plist :footnotes)
     (goto-char (point-min))
-    (let (ref mark-max)
+    (let (ref)
       (while (setq ref (org-footnote-get-next-reference))
 	(let* ((beg (nth 1 ref))
 	       (lbl (string-to-number (car ref)))
@@ -2442,7 +2447,12 @@ The conversion is made depending of STRING-BEFORE and STRING-AFTER."
 			 (push lbl org-export-latex-footmark-seen)
 			 (concat (org-export-latex-protect-string "\\footnote{")
 				 def
-				 (org-export-latex-protect-string "}")))))
+				 (org-export-latex-protect-string "}"))))
+		(sep (org-export-latex-protect-string
+		      (if (save-excursion (goto-char (1- (nth 2 ref)))
+					  (let ((next (org-footnote-get-next-reference)))
+					    (and next (= (nth 1 next) (nth 2 ref)))))
+			  org-export-latex-footnote-separator ""))))
 	    (when (org-on-heading-p)
 	      (setq fnote
 		    (concat (org-export-latex-protect-string "\\protect") fnote)))
@@ -2453,7 +2463,7 @@ The conversion is made depending of STRING-BEFORE and STRING-AFTER."
 	    ;; `org-footnote-get-next-reference' would then skip it.
 	    (goto-char beg)
 	    (delete-region beg (nth 2 ref))
-	    (save-excursion (insert fnote)))))))
+	    (save-excursion (insert fnote sep)))))))
 
   ;; Remove footnote section tag for LaTeX
   (goto-char (point-min))