Rename `org-timestamp--to-internal-time' into `org-timestamp-to-time'

* lisp/org.el (org-timestamp-to-time): New function.
(org-timestamp--to-internal-time): Remove function.
(org-timestamp-format): Use new function.

* testing/lisp/test-org.el (test-org/timestamp-to-time): New test.

etc/ORG-NEWS

@@ -196,6 +196,7 @@ a #+BEGIN_FOO/#+END_FOO block.  Bound to C-c C-x w by default.
 
 See docstring for details.
 
+*** ~org-timestamp-to-time~
 *** ~org-timestamp-from-string~
 *** ~org-timestamp-from-time~
 *** ~org-attach-dired-to-subtree~

lisp/org.el

@@ -22546,8 +22546,8 @@ return an active timestamp."
 			      :hour-start (and with-time hour)
 			      :minute-start (and with-time minute)))))
 
-(defun org-timestamp--to-internal-time (timestamp &optional end)
+(defun org-timestamp-to-time (timestamp &optional end)
-  "Encode TIMESTAMP object into Emacs internal time.
+  "Convert TIMESTAMP object into an Emacs internal time value.
 Use end of date range or time range when END is non-nil.
 Otherwise, use its start."
   (apply #'encode-time
@@ -22571,11 +22571,10 @@ FORMAT is a format specifier to be passed to
 When optional argument END is non-nil, use end of date-range or
 time-range, if possible.
 
-When optional argument UTC is non-nil, time will be expressed as
+When optional argument UTC is non-nil, time is be expressed as
 Universal Time."
-  (format-time-string
+  (format-time-string format (org-timestamp-to-time timestamp end)
-   format (org-timestamp--to-internal-time timestamp end)
+		      (and utc t)))
-   (and utc t)))
 
 (defun org-timestamp-split-range (timestamp &optional end)
   "Extract a TIMESTAMP object from a date or time range.

testing/lisp/test-org.el

@@ -6510,6 +6510,61 @@ CLOCK: [2012-03-29 Thu 10:00]--[2012-03-29 Thu 16:40] =>  6:40"
 	    (org-element-interpret-data
 	     (org-timestamp-from-time '(20339 35296) nil t))))))
 
+(ert-deftest test-org/timestamp-to-time ()
+  "Test `org-timestamp-to-time' specifications."
+  (should
+   (equal "2014-03-04"
+	  (format-time-string
+	   "%Y-%m-%d"
+	   (org-timestamp-to-time
+	    (org-timestamp-from-string "<2014-03-04 Tue>")))))
+  (should
+   (equal "2014-03-04"
+	  (format-time-string
+	   "%Y-%m-%d"
+	   (org-timestamp-to-time
+	    (org-timestamp-from-string "[2014-03-04 Tue]")))))
+  (should
+   (equal "2012-03-29 08:30"
+	  (format-time-string
+	   "%Y-%m-%d %H:%M"
+	   (org-timestamp-to-time
+	    (org-timestamp-from-string "<2012-03-29 Thu 08:30-16:40>")))))
+  (should
+   (equal "2012-03-29"
+	  (format-time-string
+	   "%Y-%m-%d"
+	   (org-timestamp-to-time
+	    (org-timestamp-from-string "<2012-03-29 Thu>--<2014-03-04 Tue>")))))
+  (should
+   (equal "2012-03-29"
+	  (format-time-string
+	   "%Y-%m-%d"
+	   (org-timestamp-to-time
+	    (org-timestamp-from-string "[2012-03-29 Thu]--[2014-03-04 Tue]")))))
+  ;; When optional argument END is non-nil, use end of date range or
+  ;; time range.
+  (should
+   (equal "2012-03-29 16:40"
+	  (format-time-string
+	   "%Y-%m-%d %H:%M"
+	   (org-timestamp-to-time
+	    (org-timestamp-from-string "<2012-03-29 Thu 08:30-16:40>")
+	    t))))
+  (should
+   (equal "2014-03-04"
+	  (format-time-string
+	   "%Y-%m-%d"
+	   (org-timestamp-to-time
+	    (org-timestamp-from-string "<2012-03-29 Thu>--<2014-03-04 Tue>")
+	    t))))
+  (should
+   (equal "2014-03-04"
+	  (format-time-string
+	   "%Y-%m-%d"
+	   (org-timestamp-to-time
+	    (org-timestamp-from-string "[2012-03-29 Thu]--[2014-03-04 Tue]")
+	    t)))))
 
 
 ;;; Visibility