From eefe696de67bd4c9baefe928a58648c75adec41e Mon Sep 17 00:00:00 2001
From: rasmus <rasmus@gmx.us>
Date: Sat, 13 Jul 2013 15:59:23 +0200
Subject: [PATCH] Improved subscript handling in ox-latex.

	* ox-latex.el (org-latex-subscript-format): Controls the
	format of subscripts.
	(org-latex-entity): Collects multiple math entities into one
	math fragment.
	(org-latex-entity): Collect proceeding subscripts into same
	math fragment.
	(org-latex--script-size): Better collection of subscripts into
	math-fragments.  Allows for different handling of
	math-subscripts and text subscripts.

In the above "subscripts" refers to subscripts and superscripts.
---
 lisp/ox-latex.el | 55 +++++++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 45 insertions(+), 10 deletions(-)

diff --git a/lisp/ox-latex.el b/lisp/ox-latex.el
index 1fe918a..183c89a 100644
--- a/lisp/ox-latex.el
+++ b/lisp/ox-latex.el
@@ -552,6 +552,20 @@ returned as-is."
   :options '(bold code italic strike-through underline verbatim))
 
 
+(defcustom org-latex-subscript-format '("\\text{%s}" . "%s")
+  "Formatting string or strings used for sub- and super-scripts.
+
+If `org-latex-subscript-format' is a cons of two strings, the first
+element will be used when a subscript is plain text,
+e.g. foo_bar, and the second will be used when a subscript is
+math, e.g. beta_t.
+
+If `org-latex-subscript-format' is a string this is used in both
+cases.
+
+The string should contain \"%s\", which is then replaced by the
+actual subscript.")
+
 ;;;; Drawers
 
 (defcustom org-latex-format-drawer-function nil
@@ -1234,8 +1248,23 @@ holding contextual information.  See `org-export-data'."
   "Transcode an ENTITY object from Org to LaTeX.
 CONTENTS are the definition itself.  INFO is a plist holding
 contextual information."
-  (let ((ent (org-element-property :latex entity)))
-    (if (org-element-property :latex-math-p entity) (format "$%s$" ent) ent)))
+  (let ((ent (org-element-property :latex entity))
+	(prev (org-export-get-previous-element entity info))
+	(next (org-export-get-next-element entity info))
+	(post-blanks-p (= (or (org-element-property :post-blank entity) 1) 0))
+	(pre-blanks-p (= (or (org-element-property :post-blank
+						   (org-export-get-previous-element
+						    entity info)) 1) 0))
+	(scripts '(subscript superscript)))
+    (if (not (org-element-property :latex-math-p entity)) ent
+      (concat
+       (if (and pre-blanks-p
+		(or (org-element-property :latex-math-p prev)
+		    (memq (org-element-type prev) scripts))) "" "$")
+       ent
+       (if (and post-blanks-p
+		(or (org-element-property :latex-math-p next)
+		    (memq (org-element-type next) scripts))) "" "$")))))
 
 
 ;;;; Example Block
@@ -2217,8 +2246,12 @@ channel."
 			   (let ((blank (org-element-property :post-blank obj)))
 			     (and blank (> blank 0) "\\ "))))))
 	  (plain-text
-	   (setq output
-		 (format "%s\\text{%s}" output (org-export-data obj info))))
+	   (let* ((mathp (org-element-property :latex-math-p (org-export-get-previous-element (org-export-get-parent obj) info)))
+		  (format (cond ((stringp org-latex-subscript-format) org-latex-subscript-format)
+				((consp org-latex-subscript-format) (funcall (if mathp 'cdr 'car) org-latex-subscript-format))
+				(t "\\text{%s}"))))
+	     (setq output
+		   (format (concat "%s" format) output (org-export-data obj info)))))
 	  (otherwise
 	   (setq output
 		 (concat output
@@ -2232,12 +2265,14 @@ channel."
     ;; superscript into the same math snippet.
     (concat (and (not in-script-p)
 		 (let ((prev (org-export-get-previous-element object info)))
-		   (or (not prev)
-		       (not (eq (org-element-type prev)
-				(if (eq type 'subscript) 'superscript
-				  'subscript)))
-		       (let ((blank (org-element-property :post-blank prev)))
-			 (and blank (> blank 0)))))
+		   (and
+		    (not (org-element-property :latex-math-p prev))
+		    (or (not prev)
+			(not (eq (org-element-type prev)
+				 (if (eq type 'subscript) 'superscript
+				   'subscript)))
+			(let ((blank (org-element-property :post-blank prev)))
+			  (and blank (> blank 0))))))
 		 "$")
 	    (if (eq (org-element-type object) 'subscript) "_" "^")
 	    (and (> (length output) 1) "{")
-- 
1.8.3.4