Implement export without DONE tasks

* doc/org.texi (Selective export): Document how to exclude DONE tasks
from export.
(Publishing options): Document the properties to be used to turn off
export of DONE tasks.
* lisp/org-ascii.el (org-export-as-ascii):
* lisp/org-docbook.el (org-export-as-docbook):
* lisp/org-html.el (org-export-as-html):
* lisp/org-latex.el (org-export-as-latex): Pass the :done-tasks property
to the export preprocessor.
* lisp/org-exp.el (org-export-with-done-tasks): New option.
(org-export-plist-vars): Add entry for :done-tasks.
(org-export-preprocess-string): Call `org-export-remove-done-tasks'.
(org-export-remove-done-tasks): New function.

doc/org.texi

@@ -9307,26 +9307,33 @@ enabled (default in Emacs 23).
 
 @node Selective export, Export options, Exporting, Exporting
 @section Selective export
-@cindex export, selective by tags
+@cindex export, selective by tags or TODO keyword
 
 @vindex org-export-select-tags
 @vindex org-export-exclude-tags
+@cindex org-export-with-done-tasks
 You may use tags to select the parts of a document that should be exported,
 or to exclude parts from export.  This behavior is governed by two variables:
 @code{org-export-select-tags} and @code{org-export-exclude-tags}.
 
-Org first checks if any of the @emph{select} tags is present in the buffer.
-If yes, all trees that do not carry one of these tags will be excluded.  If a
-selected tree is a subtree, the heading hierarchy above it will also be
-selected for export, but not the text below those headings.
+@enumerate
+@item 
+Org first checks if any of the @emph{select} tags is present in the
+buffer.  If yes, all trees that do not carry one of these tags will be
+excluded.  If a selected tree is a subtree, the heading hierarchy above it
+will also be selected for export, but not the text below those headings.
 
-@noindent
+@item
 If none of the select tags is found, the whole buffer will be selected for
 export.
 
-@noindent
+@item
 Finally, all subtrees that are marked by any of the @emph{exclude} tags will
 be removed from the export buffer.
+@end enumerate
+
+Also, if the variable @code{org-export-with-done-tasks} is @code{nil}, the
+entire subtree of entries starting with a DONE state keyword will be removed.
 
 @node Export options, The export dispatcher, Selective export, Exporting
 @section Export options
@@ -9426,6 +9433,7 @@ toc:       @r{turn on/off table of contents, or set level limit (integer)}
 -:         @r{turn on/off conversion of special strings.}
 f:         @r{turn on/off footnotes like this[1].}
 todo:      @r{turn on/off inclusion of TODO keywords into exported text}
+donetasks: @r{turn on/off inclusion of DONE tasks}
 pri:       @r{turn on/off priority cookies}
 tags:      @r{turn on/off inclusion of tags, may also be @code{not-in-toc}}
 <:         @r{turn on/off inclusion of any time/date stamps like DEADLINES}
@@ -10905,6 +10913,7 @@ respective variable for details.
 @vindex org-export-with-drawers
 @vindex org-export-with-tags
 @vindex org-export-with-todo-keywords
+@vindex org-export-with-done-tasks
 @vindex org-export-with-priority
 @vindex org-export-with-TeX-macros
 @vindex org-export-with-LaTeX-fragments
@@ -10953,6 +10962,7 @@ respective variable for details.
 @item @code{:drawers}               @tab @code{org-export-with-drawers}
 @item @code{:tags}                  @tab @code{org-export-with-tags}
 @item @code{:todo-keywords}         @tab @code{org-export-with-todo-keywords}
+@item @code{:done-tasks}            @tab @code{org-export-with-done-tasks}
 @item @code{:priority}              @tab @code{org-export-with-priority}
 @item @code{:TeX-macros}            @tab @code{org-export-with-TeX-macros}
 @item @code{:LaTeX-fragments}       @tab @code{org-export-with-LaTeX-fragments}

lisp/org-ascii.el

@@ -303,6 +303,7 @@ publishing directory."
 		  :footnotes (plist-get opt-plist :footnotes)
 		  :timestamps (plist-get opt-plist :timestamps)
 		  :todo-keywords (plist-get opt-plist :todo-keywords)
+		  :done-tasks (plist-get opt-plist :done-tasks)
 		  :verbatim-multiline t
 		  :select-tags (plist-get opt-plist :select-tags)
 		  :exclude-tags (plist-get opt-plist :exclude-tags)

lisp/org-docbook.el

@@ -529,6 +529,7 @@ publishing directory."
 	    (plist-get opt-plist :skip-before-1st-heading)
 	    :drawers (plist-get opt-plist :drawers)
 	    :todo-keywords (plist-get opt-plist :todo-keywords)
+	    :done-tasks (plist-get opt-plist :done-tasks)
 	    :tags (plist-get opt-plist :tags)
 	    :priority (plist-get opt-plist :priority)
 	    :footnotes (plist-get opt-plist :footnotes)

lisp/org-exp.el

@@ -296,6 +296,12 @@ When nil, remove all these keywords from the export."
   :group 'org-export-general
   :type 'boolean)
 
+(defcustom org-export-with-done-tasks t
+  "Non-nil means include DONE items for export.
+When nil, remove the entire subtrees belonging to DONE tasks."
+  :group 'org-export-general
+  :type 'boolean)
+
 (defcustom org-export-with-priority nil
   "Non-nil means include priority cookies in export.
 When nil, remove priority cookies for export."
@@ -621,6 +627,7 @@ table.el tables."
     (:drawers		      "d"	  org-export-with-drawers)
     (:tags		      "tags"	  org-export-with-tags)
     (:todo-keywords	      "todo"	  org-export-with-todo-keywords)
+    (:done-tasks	      "donetasks" org-export-with-done-tasks)
     (:priority		      "pri"	  org-export-with-priority)
     (:TeX-macros	      "TeX"	  org-export-with-TeX-macros)
     (:LaTeX-fragments	      "LaTeX"	  org-export-with-LaTeX-fragments)
@@ -1098,6 +1105,10 @@ on this string to produce the exported version."
 				     (plist-get parameters :exclude-tags))
       (run-hooks 'org-export-preprocess-after-tree-selection-hook)
 
+      ;; Get rid of DONE tasks if that option is configured
+      (unless (plist-get parameters :done-tasks)
+	(org-export-remove-done-tasks))
+
       ;; Change lists ending. Other parts of export may insert blank
       ;; lines and lists' structure could be altered.
       (org-export-mark-list-end)
@@ -1488,6 +1499,20 @@ removed as well."
 		    (point-max)))
       (delete-region beg end))))
 
+(defun org-export-remove-done-tasks ()
+  "Remove all tasks that are done."
+  (let ((re (concat "^\\*+[ \t]+\\("
+		    (mapconcat 'regexp-quote org-done-keywords "\\|")
+		    "\\)\\($\\|[ \t]\\)"))
+	(case-fold-search nil)
+	beg)
+    (goto-char (point-min))
+    (while (re-search-forward re nil t)
+      (org-if-unprotected
+       (setq beg (match-beginning 0))
+       (org-end-of-subtree t t)
+       (delete-region beg (point))))))
+
 (defun org-export-remove-archived-trees (export-archived-trees)
   "Remove archived trees.
 When EXPORT-ARCHIVED-TREES is `headline;, only the headline will be exported.

lisp/org-html.el

@@ -1179,6 +1179,7 @@ PUB-DIR is set, use this as the publishing directory."
 	    (plist-get opt-plist :skip-before-1st-heading)
 	    :drawers (plist-get opt-plist :drawers)
 	    :todo-keywords (plist-get opt-plist :todo-keywords)
+	    :done-tasks (plist-get opt-plist :done-tasks)
 	    :tags (plist-get opt-plist :tags)
 	    :priority (plist-get opt-plist :priority)
 	    :footnotes (plist-get opt-plist :footnotes)

lisp/org-latex.el

@@ -869,6 +869,7 @@ when PUB-DIR is set, use this as the publishing directory."
 		:drawers (plist-get opt-plist :drawers)
 		:timestamps (plist-get opt-plist :timestamps)
 		:todo-keywords (plist-get opt-plist :todo-keywords)
+		:done-tasks (plist-get opt-plist :done-tasks)
 		:add-text nil
 		:skip-before-1st-heading skip
 		:select-tags nil
@@ -886,6 +887,7 @@ when PUB-DIR is set, use this as the publishing directory."
 	   :drawers (plist-get opt-plist :drawers)
 	   :timestamps (plist-get opt-plist :timestamps)
 	   :todo-keywords (plist-get opt-plist :todo-keywords)
+	   :done-tasks (plist-get opt-plist :done-tasks)
 	   :add-text (if (eq to-buffer 'string) nil text)
 	   :skip-before-1st-heading skip
 	   :select-tags (plist-get opt-plist :select-tags)