Make S-right/left work in column view for any timestamp

value of a property.

ORGWEBPAGE/Changes.org

@@ -187,6 +187,13 @@
     For more information, look at the variable
  =org-columns-modify-value-for-display-function=.
 
+*** In column view, date stamps now always have allowed values defined.
+
+    If a property value is a time stamp, S-left and S-right can
+    now be used to shift this date around.
+
+    This was a request by Chris Randle.
+
 * Version 6.06
 
 ** Overview

doc/org.texi

@@ -3625,15 +3625,6 @@ release, number of tracks, and so on.
 Properties can be conveniently edited and viewed in column view
 (@pxref{Column view}).
 
-Properties are like tags, but with a value.  For example, in a file
-where you document bugs and plan releases of a piece of software,
-instead of using tags like @code{:release_1:}, @code{:release_2:}, it
-can be more efficient to use a property @code{:Release:} with a value
-@code{1.0} or @code{2.0}.  Second, you can use properties to implement
-(very basic) database capabilities in an Org buffer, for example to
-create a list of Music CD's you own.  You can edit and view properties
-conveniently in column view (@pxref{Column view}).
-
 @menu
 * Property syntax::             How properties are spelled out
 * Special properties::          Access to other Org mode features
@@ -4034,7 +4025,7 @@ current column view.
 Make the column narrower/wider by one character.
 @kindex S-M-@key{right}
 @item S-M-@key{right}
-Insert a new column, to the right of the current column.
+Insert a new column, to the left of the current column.
 @kindex S-M-@key{left}
 @item S-M-@key{left}
 Delete the current column.

lisp/ChangeLog

@@ -1,3 +1,15 @@
+2008-09-18  Carsten Dominik  <dominik@science.uva.nl>
+
+	* org-colview.el (org-colview-construct-allowed-dates): New
+	function. 
+	(org-columns-next-allowed-value): Use
+	`org-colview-construct-allowed-dates'.
+
+	* org-colview-xemacs.el (org-colview-construct-allowed-dates): New
+	function.
+	(org-columns-next-allowed-value): Use
+	`org-colview-construct-allowed-dates'.
+
 2008-09-17  Carsten Dominik  <dominik@science.uva.nl>
 
 	* org.el (org-protect-slash): New function.

lisp/org-colview-xemacs.el

@@ -735,7 +735,8 @@ an integer, select that value."
 		      (and (memq
 			    (nth 4 (assoc key org-columns-current-fmt-compiled))
 			    '(checkbox checkbox-n-of-m checkbox-percent))
-			   '("[ ]" "[X]"))))
+			   '("[ ]" "[X]"))
+		      (org-colview-construct-allowed-dates value)))
 	 nval)
     (when (integerp nth)
       (setq nth (1- nth))
@@ -784,6 +785,26 @@ an integer, select that value."
       (and (nth 3 (assoc key org-columns-current-fmt-compiled))
 	   (org-columns-update key))))))
 
+(defun org-colview-construct-allowed-dates (s)
+  "Construct a list of three dates around the date in S.
+This respects the format of the time stamp in S, active or non-active,
+and also including time or not.  S must be just a time stamp, no text
+around it."
+  (when (string-match (concat "^" org-ts-regexp3 "$") s)
+    (let* ((time (org-parse-time-string s 'nodefaults))
+	   (active (equal (string-to-char s) ?<))
+	   (fmt (funcall (if (nth 1 time) 'cdr 'car) org-time-stamp-formats)))
+      (unless active (setq fmt (concat "[" (substring fmt 1 -1) "]")))
+      (setf (car time) (or (car time) 0))
+      (setf (nth 1 time) (or (nth 1 time) 0))
+      (setf (nth 2 time) (or (nth 2 time) 0))
+      (setq time-before (copy-sequence time))
+      (setq time-after (copy-sequence time))
+      (setf (nth 3 time-before) (1- (nth 3 time)))
+      (setf (nth 3 time-after) (1+ (nth 3 time)))
+      (mapcar (lambda (x) (format-time-string fmt (apply 'encode-time x)))
+	      (list time-before time time-after)))))
+
 (defun org-verify-version (task)
   (cond
    ((eq task 'columns)

lisp/org-colview.el

@@ -538,7 +538,8 @@ an integer, select that value."
 		      (and (memq
 			    (nth 4 (assoc key org-columns-current-fmt-compiled))
 			    '(checkbox checkbox-n-of-m checkbox-percent))
-			   '("[ ]" "[X]"))))
+			   '("[ ]" "[X]"))
+		      (org-colview-construct-allowed-dates value)))
 	 nval)
     (when (integerp nth)
       (setq nth (1- nth))
@@ -587,6 +588,26 @@ an integer, select that value."
       (and (nth 3 (assoc key org-columns-current-fmt-compiled))
 	   (org-columns-update key))))))
 
+(defun org-colview-construct-allowed-dates (s)
+  "Construct a list of three dates around the date in S.
+This respects the format of the time stamp in S, active or non-active,
+and also including time or not.  S must be just a time stamp, no text
+around it."
+  (when (string-match (concat "^" org-ts-regexp3 "$") s)
+    (let* ((time (org-parse-time-string s 'nodefaults))
+	   (active (equal (string-to-char s) ?<))
+	   (fmt (funcall (if (nth 1 time) 'cdr 'car) org-time-stamp-formats)))
+      (unless active (setq fmt (concat "[" (substring fmt 1 -1) "]")))
+      (setf (car time) (or (car time) 0))
+      (setf (nth 1 time) (or (nth 1 time) 0))
+      (setf (nth 2 time) (or (nth 2 time) 0))
+      (setq time-before (copy-sequence time))
+      (setq time-after (copy-sequence time))
+      (setf (nth 3 time-before) (1- (nth 3 time)))
+      (setf (nth 3 time-after) (1+ (nth 3 time)))
+      (mapcar (lambda (x) (format-time-string fmt (apply 'encode-time x)))
+	      (list time-before time time-after)))))
+
 (defun org-verify-version (task)
   (cond
    ((eq task 'columns)