contrib/lisp/ox-extra.el: new file

contrib/lisp/ox-extra.el

@@ -0,0 +1,111 @@
+;;; ox-extra.el --- Convenience functions for org export
+
+;; Copyright (C) 2014  Aaron Ecay
+
+;; Author: Aaron Ecay <aaronecay@gmail.com>
+
+;; This program is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; This program is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; This file contains some convenience functions for org export, which
+;; are not part of org's core.  Call `ox-extras-activate' passing a
+;; list of symbols naming extras, which will be installed globally in
+;; your org session.
+
+;; Currently available extras:
+
+;; - `latex-header-blocks' -- allow the use of latex blocks, the
+;; contents of which which will be interpreted as #+latex_header lines
+;; for export.  These blocks should be tagged with #+header: :header
+;; yes.  For example:
+;; #+header: :header yes
+;; #+begin_latex
+;;   ...
+;; #+end_latex
+
+;; TODO:
+;; - add a function to org-mode-hook that looks for a ox-extras local
+;;   variable and activates the specified extras buffer-locally
+;; - allow specification of desired extras to be activated via
+;;   customize
+
+;;; Code:
+
+(require 'ox)
+(eval-when-compile (require 'cl))
+
+(defun org-latex-header-blocks-filter ()
+  (let ((positions
+	 (org-element-map (org-element-parse-buffer 'greater-element nil) 'export-block
+	   (lambda (block)
+	     (when (and (string= (org-element-property :type block) "LATEX")
+			(string= (org-export-read-attribute
+				  :header block :header)
+				 "yes"))
+	       (list (org-element-property :begin block)
+		     (org-element-property :end block)
+		     (org-element-property :post-affiliated block)))))))
+    (mapc (lambda (pos)
+	    (goto-char (nth 2 pos))
+	    (destructuring-bind
+		(beg end &rest ignore)
+		(org-edit-src-find-region-and-lang)
+	      (let ((contents-lines (split-string
+				     (buffer-substring-no-properties beg end)
+				     "\n")))
+		(delete-region (nth 0 pos) (nth 1 pos))
+		(dolist (line contents-lines)
+		  (insert (concat "#+latex_header: "
+				  (replace-regexp-in-string "\\` *" "" line)
+				  "\n"))))))
+	  ;; go in reverse, to avoid wrecking the numeric positions
+	  ;; earlier in the file
+	  (reverse positions))))
+
+(defconst ox-extras
+  '((latex-header-blocks org-latex-latex-header-blocks-filter org-export-before-parsing-hook))
+  "A list of org export extras that can be enabled.
+
+Should be a list of items of the form (NAME FN HOOK).  NAME is a
+symbol, which can be passed to `ox-extras-activate'.  FN is a
+function which will be added to HOOK.")
+
+(defun ox-extras-activate (extras)
+  "Activate certain org export extras.
+
+EXTRAS should be a list of extras (defined in `ox-extras') which
+should be activated."
+  (dolist (extra extras)
+    (let* ((lst (assq extra ox-extras))
+	   (fn (nth 1 lst))
+	   (hook (nth 2 lst)))
+      (when (and fn hook)
+	(add-hook hook fn)))))
+
+(defun ox-extras-deactivate (extras)
+  "Deactivate certain org export extras.
+
+This function is the opposite of `ox-extras-activate'.  EXTRAS
+should be a list of extras (defined in `ox-extras') which should
+be activated."
+  (dolist (extra extras)
+    (let* ((lst (assq extra ox-extras))
+	   (fn (nth 1 lst))
+	   (hook (nth 2 lst)))
+      (when (and fn hook)
+	(remove-hook hook fn)))))
+
+(provide 'ox-extra)
+;;; ox-extra.el ends here