dotimes-with-progress-reporter: Polymorphic 2nd argument

* lisp/subr.el (dotimes-with-progress-reporter): Allow 2nd arg to be
a string or a progress reporter (Bug#31696).
* doc/lispref/display.texi (node Progress): Update manual.

2 files changed, 33 insertions, 19 deletions

diff --git a/doc/lispref/display.texi b/doc/lispref/display.texi
index 0ba7f0fd586..12c36bb08ff 100644
--- a/doc/lispref/display.texi
+++ b/doc/lispref/display.texi
@@ -469,7 +469,7 @@ never print it, there are many good reasons for this not to happen.
 Secondly, @samp{done} is more explicit.
 @end defun
 
-@defmac dotimes-with-progress-reporter (var count [result]) message body@dots{}
+@defmac dotimes-with-progress-reporter (var count [result]) reporter-or-message body@dots{}
 This is a convenience macro that works the same way as @code{dotimes}
 does, but also reports loop progress using the functions described
 above.  It allows you to save some typing.
@@ -483,6 +483,18 @@ this macro this way:
     "Collecting some mana for Emacs..."
   (sit-for 0.01))
 @end example
+
+
+The second argument @code{reporter-or-message} might be a progress
+reporter object.  This is useful if you want to specify the optional
+arguments in @code{make-progress-reporter}.
+For instance, you can write previous example as follows:
+@example
+(dotimes-with-progress-reporter
+    (k 500)
+    (make-progress-reporter "Collecting some mana for Emacs..." 0 500 0 1 1.5)
+  (sit-for 0.01))
+@end example
 @end defmac
 
 @node Logging Messages
diff --git a/lisp/subr.el b/lisp/subr.el
index 8123e60f62a..d4383f862af 100644
--- a/lisp/subr.el
+++ b/lisp/subr.el
@@ -5039,32 +5039,34 @@ NEW-MESSAGE, if non-nil, sets a new message for the reporter."
   "Print reporter's message followed by word \"done\" in echo area."
   (message "%sdone" (aref (cdr reporter) 3)))
 
-(defmacro dotimes-with-progress-reporter (spec message &rest body)
+(defmacro dotimes-with-progress-reporter (spec reporter-or-message &rest body)
   "Loop a certain number of times and report progress in the echo area.
 Evaluate BODY with VAR bound to successive integers running from
 0, inclusive, to COUNT, exclusive.  Then evaluate RESULT to get
 the return value (nil if RESULT is omitted).
 
-At each iteration MESSAGE followed by progress percentage is
-printed in the echo area.  After the loop is finished, MESSAGE
-followed by word \"done\" is printed.  This macro is a
-convenience wrapper around `make-progress-reporter' and friends.
+REPORTER-OR-MESSAGE is a progress reporter object or a string.  In the latter
+case, use this string to create a progress reporter.
+
+At each iteration, print the reporter message followed by progress
+percentage in the echo area.  After the loop is finished,
+print the reporter message followed by word \"done\".
+
+This macro is a convenience wrapper around `make-progress-reporter' and friends.
 
 \(fn (VAR COUNT [RESULT]) MESSAGE BODY...)"
   (declare (indent 2) (debug ((symbolp form &optional form) form body)))
-  (let ((temp (make-symbol "--dotimes-temp--"))
-        (temp2 (make-symbol "--dotimes-temp2--"))
-        (start 0)
-        (end (nth 1 spec)))
-    `(let ((,temp ,end)
-           (,(car spec) ,start)
-           (,temp2 (make-progress-reporter ,message ,start ,end)))
-       (while (< ,(car spec) ,temp)
-         ,@body
-         (progress-reporter-update ,temp2
-                                   (setq ,(car spec) (1+ ,(car spec)))))
-       (progress-reporter-done ,temp2)
-       nil ,@(cdr (cdr spec)))))
+  (let ((prep (make-symbol "--dotimes-prep--"))
+        (end (make-symbol "--dotimes-end--")))
+    `(let ((,prep ,reporter-or-message)
+           (,end ,(cadr spec)))
+       (when (stringp ,prep)
+         (setq ,prep (make-progress-reporter ,prep 0 ,end)))
+       (dotimes (,(car spec) ,end)
+         ,@body
+         (progress-reporter-update ,prep (1+ ,(car spec))))
+       (progress-reporter-done ,prep)
+       (or ,@(cdr (cdr spec)) nil))))
 
 
 ;;;; Comparing version strings.