Combine archive-int-to-mode and tar-grind-file-modebug27952_combine-tar-grind-file-mode_archive-int-to-mode

Add a new function, file-modes-number-to-symbolic.
Make archive-int-to-mode and obsolete alias of it; use it
to define tar-grind-file-mode (Bug#27952).

* lisp/files.el (file-modes-number-to-symbolic): New defun.
* lisp/arc-mode.el (archive-int-to-mode): Make it an obsolete alias.
* lisp/tar-mode.el (tar-grind-file-mode):
Use file-modes-number-to-symbolic.

* test/lisp/arc-mode-tests.el (arc-mode-test-archive-int-to-mode)
* test/lisp/tar-mode-tests.el (tar-mode-test-tar-grind-file-mode):
Update test.

* test/lisp/files-tests.el (files-tests-file-modes-symbolic-to-number)
(files-tests-file-modes-number-to-symbolic): New tests.

* doc/lispref/files.texi (Changing Files): Document the new funtion.
* etc/NEWS (Lisp Changes in Emacs 28.1): Announce it.

1 files changed, 4 insertions, 0 deletions

diff --git a/etc/NEWS b/etc/NEWS
index ae676a9bf83..8a1d51c18d7 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -400,6 +400,10 @@ Use macro 'with-current-buffer-window' with action alist entry 'body-function'.
 
 * Lisp Changes in Emacs 28.1
 
++++
+** New function 'file-modes-number-to-symbolic' to convert a numeric
+file mode specification into symbolic form.
+
 ** New macro 'dlet' to dynamically bind variables.
 
 ** The variable 'force-new-style-backquotes' has been removed.