Implement `org-timestamp-from-string', `org-timestamp-from-time'

* lisp/org.el (org-timestamp-from-string):
(org-timestamp-from-time): New functions.

* testing/lisp/test-org.el (test-org/timestamp-from-string):
(test-org/timestamp-from-time): New tests.

etc/ORG-NEWS

@@ -196,6 +196,8 @@ a #+BEGIN_FOO/#+END_FOO block.  Bound to C-c C-x w by default.
 
 See docstring for details.
 
+*** ~org-timestamp-from-string~
+*** ~org-timestamp-from-time~
 *** ~org-attach-dired-to-subtree~
 
 See docstring for details.

lisp/org.el

@@ -22515,12 +22515,40 @@ Call `org-toggle-comment' if on a heading, otherwise call
 
 ;;; Timestamps API
 
-;; This section contains tools to operate on timestamp objects, as
-;; returned by, e.g. `org-element-context'.
+;; This section contains tools to operate on, or create, timestamp
+;; objects, as returned by, e.g. `org-element-context'.
+
+(defun org-timestamp-from-string (s)
+  "Convert Org timestamp S, as a string, into a timestamp object.
+Return nil if S is not a valid timestamp string."
+  (when (org-string-nw-p s)
+    (with-temp-buffer
+      (save-excursion (insert s))
+      (org-element-timestamp-parser))))
+
+(defun org-timestamp-from-time (time &optional with-time inactive)
+  "Convert a time value into a timestamp object.
+
+TIME is an Emacs internal time representation, as returned, e.g.,
+by `current-time'.
+
+When optional argument WITH-TIME is non-nil, return a
+
+Return an inactive timestamp if INACTIVE is non-nil.  Otherwise,
+return an active timestamp."
+  (pcase-let ((`(,_ ,minute ,hour ,day ,month ,year . ,_) (decode-time time)))
+    (org-element-create 'timestamp
+			(list :type (if inactive 'inactive 'active)
+			      :year-start year
+			      :month-start month
+			      :day-start day
+			      :hour-start (and with-time hour)
+			      :minute-start (and with-time minute)))))
 
 (defun org-timestamp--to-internal-time (timestamp &optional end)
   "Encode TIMESTAMP object into Emacs internal time.
-Use end of date range or time range when END is non-nil."
+Use end of date range or time range when END is non-nil.
+Otherwise, use its start."
   (apply #'encode-time
 	 (cons 0
 	       (mapcar

testing/lisp/test-org.el

@@ -6469,6 +6469,47 @@ CLOCK: [2012-03-29 Thu 10:00]--[2012-03-29 Thu 16:40] =>  6:40"
 		  (org-time-stamp-custom-formats '("<%d>" . "<%d>")))
 	      (org-timestamp-translate (org-element-context)))))))
 
+(ert-deftest test-org/timestamp-from-string ()
+  "Test `org-timestamp-from-string' specifications."
+  ;; Return nil if argument is not a valid Org timestamp.
+  (should-not (org-timestamp-from-string ""))
+  (should-not (org-timestamp-from-string nil))
+  (should-not (org-timestamp-from-string "<2012-03-29"))
+  ;; Otherwise, return a valid Org timestamp object.
+  (should
+   (equal "<2012-03-29 Thu>"
+	  (let ((system-time-locale "en_US"))
+	       (org-element-interpret-data
+		(org-timestamp-from-string "<2012-03-29 Thu>")))))
+  (should
+   (equal "[2014-03-04 Tue]"
+	  (let ((system-time-locale "en_US"))
+	       (org-element-interpret-data
+		(org-timestamp-from-string "[2014-03-04 Tue]"))))))
+
+(ert-deftest test-org/timestamp-from-time ()
+  "Test `org-timestamp-from-time' specifications."
+  ;; Standard test.
+  (should
+   (equal "<2012-03-29 Thu>"
+	  (let ((system-time-locale "en_US"))
+	    (org-element-interpret-data
+	     (org-timestamp-from-time '(20339 35296))))))
+  ;; When optional argument WITH-TIME is non-nil, provide time
+  ;; information.
+  (should
+   (equal "<2012-03-29 Thu 16:40>"
+	  (let ((system-time-locale "en_US"))
+	    (org-element-interpret-data
+	     (org-timestamp-from-time '(20340 29760) t)))))
+  ;; When optional argument INACTIVE is non-nil, return an inactive
+  ;; timestamp.
+  (should
+   (equal "[2012-03-29 Thu]"
+	  (let ((system-time-locale "en_US"))
+	    (org-element-interpret-data
+	     (org-timestamp-from-time '(20339 35296) nil t))))))
+
 
 
 ;;; Visibility