org-export: Add a subtree property for each export option

* contrib/lisp/org-export.el (org-export-get-subtree-options): Add
  a subtree property for each export option.
* testing/lisp/test-org-export.el: Add tests.

Properties names are obtained by adding "EXPORT_" prefix to buffer
keywords.

contrib/lisp/org-export.el

@@ -176,11 +176,15 @@
 The CAR of the alist is the property name, and the CDR is a list
 like (KEYWORD OPTION DEFAULT BEHAVIOUR) where:
 
-KEYWORD is a string representing a buffer keyword, or nil.
+KEYWORD is a string representing a buffer keyword, or nil.  Each
+  property defined this way can also be set, during subtree
+  export, through an headline property named after the keyword
+  with the \"EXPORT_\" prefix (i.e. DATE keyword and EXPORT_DATE
+  property).
 OPTION is a string that could be found in an #+OPTIONS: line.
 DEFAULT is the default value for the property.
 BEHAVIOUR determine how Org should handle multiple keywords for
-the same property.  It is a symbol among:
+  the same property.  It is a symbol among:
   nil       Keep old value and discard the new one.
   t         Replace old value with the new one.
   `space'   Concatenate the values, separating them with a space.
@@ -1134,10 +1138,15 @@ specific items to read, if any."
   "Get export options in subtree at point.
 Optional argument BACKEND is a symbol specifying back-end used
 for export.  Return options as a plist."
+  ;; For each buffer keyword, create an headline property setting the
+  ;; same property in communication channel. The name for the property
+  ;; is the keyword with "EXPORT_" appended to it.
   (org-with-wide-buffer
    (let (prop plist)
      ;; Make sure point is at an heading.
      (unless (org-at-heading-p) (org-back-to-heading t))
+     ;; Take care of EXPORT_TITLE. If it isn't defined, use headline's
+     ;; title as its fallback value.
      (when (setq prop (progn (looking-at org-todo-line-regexp)
 			     (or (save-match-data
 				   (org-entry-get (point) "EXPORT_TITLE"))
@@ -1147,13 +1156,37 @@ for export.  Return options as a plist."
 	      plist :title
 	      (org-element-parse-secondary-string
 	       prop (org-element-restriction 'keyword)))))
-     (when (setq prop (org-entry-get (point) "EXPORT_AUTHOR"))
-       (setq plist (plist-put plist :author prop)))
-     (when (setq prop (org-entry-get (point) "EXPORT_DATE"))
-       (setq plist (plist-put plist :date prop)))
+     ;; EXPORT_OPTIONS are parsed in a non-standard way.
      (when (setq prop (org-entry-get (point) "EXPORT_OPTIONS"))
        (setq plist
 	     (nconc plist (org-export-parse-option-keyword prop backend))))
+     ;; Handle other keywords.
+     (let ((seen '("TITLE")))
+       (mapc
+	(lambda (option)
+	  (let ((property (nth 1 option)))
+	    (when (and property (not (member property seen)))
+	      (let* ((subtree-prop (concat "EXPORT_" property))
+		     (value (org-entry-get (point) subtree-prop)))
+		(push property seen)
+		(when value
+		  (setq plist
+			(plist-put
+			 plist
+			 (car option)
+			 ;; Parse VALUE if required.
+			 (if (member property org-element-parsed-keywords)
+			     (org-element-parse-secondary-string
+			      value (org-element-restriction 'keyword))
+			   value))))))))
+	;; Also look for both general keywords and back-end specific
+	;; options if BACKEND is provided.
+	(append (and backend
+		     (let ((var (intern
+				 (format "org-%s-options-alist" backend))))
+		       (and (boundp var) (symbol-value var))))
+		org-export-options-alist)))
+     ;; Return value.
      plist)))
 
 (defun org-export-get-inbuffer-options (&optional backend files)

testing/lisp/test-org-export.el

@@ -99,10 +99,10 @@ already filled in `info'."
 #+DESCRIPTION: Testing
 #+DESCRIPTION: with two lines
 #+EMAIL: some@email.org
-#+EXPORT_EXCLUDE_TAGS: noexport invisible
+#+EXCLUDE_TAGS: noexport invisible
 #+KEYWORDS: test
 #+LANGUAGE: en
-#+EXPORT_SELECT_TAGS: export
+#+SELECT_TAGS: export
 #+TITLE: Some title
 #+TITLE: with spaces"
       (org-export-get-inbuffer-options))
@@ -112,6 +112,41 @@ already filled in `info'."
       :exclude-tags ("noexport" "invisible") :keywords "test" :language "en"
       :select-tags ("export") :title ("Some title with spaces")))))
 
+(ert-deftest test-org-export/get-subtree-options ()
+  "Test setting options from headline's properties."
+  ;; EXPORT_TITLE.
+  (org-test-with-temp-text "#+TITLE: Title
+* Headline
+  :PROPERTIES:
+  :EXPORT_TITLE: Subtree Title
+  :END:
+Paragraph"
+    (forward-line)
+    (should (equal (plist-get (org-export-get-environment nil t) :title)
+		   '("Subtree Title"))))
+  :title
+  '("subtree-title")
+  ;; EXPORT_OPTIONS.
+  (org-test-with-temp-text "#+OPTIONS: H:1
+* Headline
+  :PROPERTIES:
+  :EXPORT_OPTIONS: H:2
+  :END:
+Paragraph"
+    (forward-line)
+    (should
+     (= 2 (plist-get (org-export-get-environment nil t) :headline-levels))))
+  ;; EXPORT DATE.
+  (org-test-with-temp-text "#+DATE: today
+* Headline
+  :PROPERTIES:
+  :EXPORT_DATE: 29-03-2012
+  :END:
+Paragraph"
+    (forward-line)
+    (should (equal (plist-get (org-export-get-environment nil t) :date)
+		   '("29-03-2012")))))
+
 (ert-deftest test-org-export/handle-options ()
   "Test if export options have an impact on output."
   ;; Test exclude tags.
@@ -278,41 +313,7 @@ text
 #+END_SRC"
     (org-test-with-backend test
       (forward-line 1)
-      (should (equal (org-export-as 'test 'subtree) ": 3\n"))))
-  ;; Subtree's EXPORT_TITLE property.
-  (should
-   (equal
-    (plist-get (org-test-with-temp-text "* Headline
-  :PROPERTIES:
-  :EXPORT_TITLE: subtree-title
-  :END:
-Paragraph"
-		 (org-export-get-environment nil t))
-	       :title)
-    '("subtree-title")))
-  ;; Subtree's EXPORT_TITLE property.
-  (org-test-with-temp-text "#+OPTIONS: H:1
-* Headline
-  :PROPERTIES:
-  :EXPORT_OPTIONS: H:2
-  :END:
-Paragraph"
-    (forward-line)
-    (should
-     (= 2 (plist-get (org-export-get-environment nil t) :headline-levels)))))
-
-(ert-deftest test-org-export/export-snippet ()
-  "Test export snippets transcoding."
-  (org-test-with-temp-text "@@test:A@@@@t:B@@"
-    (org-test-with-backend test
-      (flet ((org-test-export-snippet
-	      (snippet contents info)
-	      (when (eq (org-export-snippet-backend snippet) 'test)
-		(org-element-property :value snippet))))
-	(let ((org-export-snippet-translation-alist nil))
-	  (should (equal (org-export-as 'test) "A\n")))
-	(let ((org-export-snippet-translation-alist '(("t" . "test"))))
-	  (should (equal (org-export-as 'test) "AB\n")))))))
+      (should (equal (org-export-as 'test 'subtree) ": 3\n")))))
 
 (ert-deftest test-org-export/expand-include ()
   "Test file inclusion in an Org buffer."
@@ -427,6 +428,24 @@ body\n")))
     :attr_html
     (org-test-with-temp-text "Paragraph" (org-element-current-element)))))
 
+
+
+;;; Export Snippets
+
+(ert-deftest test-org-export/export-snippet ()
+  "Test export snippets transcoding."
+  (org-test-with-temp-text "@@test:A@@@@t:B@@"
+    (org-test-with-backend test
+      (flet ((org-test-export-snippet
+	      (snippet contents info)
+	      (when (eq (org-export-snippet-backend snippet) 'test)
+		(org-element-property :value snippet))))
+	(let ((org-export-snippet-translation-alist nil))
+	  (should (equal (org-export-as 'test) "A\n")))
+	(let ((org-export-snippet-translation-alist '(("t" . "test"))))
+	  (should (equal (org-export-as 'test) "AB\n")))))))
+
+
 
 ;;; Footnotes