Backends now register with org-lparse during load time

* contrib/lisp/org-lparse.el (org-lparse-native-backends): Set
default value to nil. Also update docstring.
(org-lparse-register-backend): New
* contrib/lisp/org-xhtml.el (org-xhtml-get): Add self -
"xhtml" - as one of the other backends. Call
org-lparse-register-backend on load.
* contrib/lisp/org-odt.el: Call org-lparse-register-backend on
load.

contrib/lisp/org-lparse.el

@@ -337,9 +337,11 @@ OPT-PLIST is the export options list."
      (when org-lparse-do-open-par
        (org-lparse-begin-paragraph))))
 
-(defvar org-lparse-native-backends
-  '("xhtml" "odt")
+(defvar org-lparse-native-backends nil
   "List of native backends registered with `org-lparse'.
+A backend can use `org-lparse-register-backend' to add itself to
+this list.
+
 All native backends must implement a get routine and a mandatory
 set of callback routines.
 
@@ -354,6 +356,16 @@ For the sake of illustration, the html backend implements
 `org-xhtml-entity-format-callbacks-alist' as the values of
 ENTITY-CONTROL and ENTITY-FORMAT settings.")
 
+(defun org-lparse-register-backend (backend)
+  "Make BACKEND known to org-lparse library.
+Add BACKEND to `org-lparse-native-backends'."
+  (when backend
+    (setq backend (cond
+		   ((symbolp backend) (symbol-name backend))
+		   ((stringp backend) backend)
+		   (t (error "Error while registering backend: %S" backend))))
+    (add-to-list 'org-lparse-native-backends backend)))
+
 (defun org-lparse-get-other-backends (native-backend)
   (org-lparse-backend-get native-backend 'OTHER-BACKENDS))
 

contrib/lisp/org-odt.el

@@ -128,9 +128,12 @@
 		(cons (concat  "\\." (car desc) "\\'") 'system)))
  org-odt-ms-file-extensions)
 
-;; register the odt exporter
+;; register the odt exporter with the pre-processor
 (add-to-list 'org-export-backends 'odt)
 
+;; register the odt exporter with org-lparse library
+(org-lparse-register-backend 'odt)
+
 (defcustom org-export-odt-automatic-styles-file nil
   "Default style file for use with ODT exporter."
   :type 'file

contrib/lisp/org-xhtml.el

@@ -1194,6 +1194,9 @@ make any modifications to the exporter file.  For example,
 `org-xhtml-format-table-row' encloses incoming entity in <tr>
 </tr> tags and returns it.  See also `org-lparse-format'.")
 
+;; register the xhtml exporter with org-lparse library
+(org-lparse-register-backend 'xhtml)
+
 (defun org-xhtml-begin-document-body (opt-plist)
   (let ((link-up (and (plist-get opt-plist :link-up)
 		      (string-match "\\S-" (plist-get opt-plist :link-up))
@@ -1652,7 +1655,7 @@ lang=\"%s\" xml:lang=\"%s\">
     (SAVE-METHOD nil)
     (CLEANUP-METHOD nil)
     (OTHER-BACKENDS
-     '("etext" "html" "html10" "mediawiki" "pdf" "sdw" "sdw3" "sdw4"
+     '("xhtml" "etext" "html" "html10" "mediawiki" "pdf" "sdw" "sdw3" "sdw4"
        "text" "text10" "odt" "vor" "vor4"))
     (CONVERT-METHOD org-lparse-convert-process)
     (EXPORT-DIR (org-export-directory :html opt-plist))