Re: Bug: possible bug in latex export [7.01trans (release_6.36.735.g15ca.dirty)]

[Stephen Eglen <S.J.Eglen@damtp.cam.ac.uk>]

> FYI: This is a know limitation of the LaTeX exporter[1] and the
> current state of this issue (dealing with skipped levels) is that
> patches for the problem are welcome.  I agree that even if
> skipped-level-headlines are not allowed, they shouldn't be silently
> droped neither.
> 
> Best,
>   -- David
> 
> [1] http://thread.gmane.org/gmane.emacs.orgmode/26413

I think I have a patch for this, see below.  I've tested it briefly to
see that it works with both oddeven and odd level headings, but I would
appreciate other people taking a closer look/checking that it doesn't
break other things.  I think I found the problem, in that if you have a
structure like

* A 

*** B

(i.e. a level one and a level 3)

after it has found the level 1 content, it expects to find a level 2
subtree, whereas in fact there could be a level 2+ tree.  See the
comment in the code for the change I made.

Stephen

diff --git a/lisp/org-latex.el b/lisp/org-latex.el
index 24dd8c1..8530723 100644
--- a/lisp/org-latex.el
+++ b/lisp/org-latex.el
@@ -937,13 +937,28 @@ Return a list reflecting the document structure."
 (defun org-export-latex-parse-subcontent (level odd)
   "Extract the subcontent of a section at LEVEL.
 If ODD Is non-nil, assume subcontent only contains odd sections."
-  (if (not (org-re-search-forward-unprotected
-	    (concat "^\\(\\(?:\\*\\)\\{"
-		    (number-to-string (+ (if odd 4 2) level))
-		    "\\}\\) \\(.*\\)$")
-	    nil t))
-      nil ; subcontent is nil
-    (org-export-latex-parse-global (+ (if odd 2 1) level) odd)))
+
+  (let (nstars new-level)
+    ;; In the search, we should not assume there will be exactly
+    ;; LEVEL+1 stars in the next heading, as there may be more than
+    ;; that number of stars.  hence the regexp should be \\*{N,}
+    ;; rather than just \\*{N} (i.e. no upper bound, but N is minimum
+    ;; number of stars to expect.)
+    ;; We then have to check how many stars were found, rather than
+    ;; assuming there were exactly N.
+    (when (org-re-search-forward-unprotected
+	   (concat "^\\(\\(?:\\*\\)\\{"
+		   (number-to-string (+ (if odd 4 2) level))
+		   ",\\}\\) \\(.*\\)$")
+	   nil t)
+      (setq nstars (1- (- (match-end 1) (match-beginning 1))))
+      (setq new-level (if odd 
+			  (/ (+ 3 nstars) 2);; not entirely sure why +3!
+			nstars)))
+    (if nstars
+	(org-export-latex-parse-global new-level odd)
+      nil)				; subcontent is nil
+      ))
 
 ;;; Rendering functions:
 (defun org-export-latex-global (content)