From bfec0bd8971e93c85353f7415960fdbbfe6c3f01 Mon Sep 17 00:00:00 2001
From: Stefan Kangas <stefan@marxist.se>
Date: Sun, 14 Feb 2021 20:45:56 +0100
Subject: [PATCH] Add new forward compatibility package 'future-interactive'

* lisp/emacs-lisp/future-interactive.el:
* test/lisp/emacs-lisp/future-interactive-tests.el: New files.
---
 lisp/emacs-lisp/future-interactive.el         | 58 +++++++++++++++++++
 .../emacs-lisp/future-interactive-tests.el    | 38 ++++++++++++
 2 files changed, 96 insertions(+)
 create mode 100644 lisp/emacs-lisp/future-interactive.el
 create mode 100644 test/lisp/emacs-lisp/future-interactive-tests.el

diff --git a/lisp/emacs-lisp/future-interactive.el b/lisp/emacs-lisp/future-interactive.el
new file mode 100644
index 0000000000..fe12924194
--- /dev/null
+++ b/lisp/emacs-lisp/future-interactive.el
@@ -0,0 +1,58 @@
+;;; future-interactive.el --- Forward compatibility for `interactive' in Emacs 28.  -*- lexical-binding: t; -*-
+
+;; Copyright (C) 2021 Free Software Foundation, Inc.
+
+;; Author: Stefan Kangas <stefankangas@gmail.com>
+;; Keywords: lisp, compatibility
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs is free software: you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; This is a forward compatibility package to allow maintaining
+;; support for older versions of Emacs while also using the new third
+;; argument to the `interactive'form added in Emacs 28.
+;;
+;; To use this in a package, just add a dependency on this package and
+;; replace `interactive' with `future-interactive':
+;;
+;;     (require 'future-interactive)
+;;
+;;     (defun foo-command ()
+;;       (future-interactive nil foo-mode)
+;;       ... )
+;;
+;; See the `future-interactive' macro for more information.
+
+;;; Code:
+
+;; This is a GNU ELPA :core package to be able to easily use this in
+;; other :core packages.
+
+(defmacro future-interactive (arg-descriptor &rest modes)
+  "Use the correct `interactive' form for any Emacs version.
+
+This is a forward compatibility macro that allows packages to
+provide the third argument to `interactive' (added in Emacs 28)
+while still working on older versions of Emacs.
+
+To use it, simply replace `interactive' with `future-interactive'."
+  (if (< emacs-major-version 28)
+      `(interactive ,arg-descriptor)
+    `(interactive ,arg-descriptor ,@modes)))
+
+(provide 'future-interactive)
+;;; future-interactive.el ends here
diff --git a/test/lisp/emacs-lisp/future-interactive-tests.el b/test/lisp/emacs-lisp/future-interactive-tests.el
new file mode 100644
index 0000000000..f525d03fcb
--- /dev/null
+++ b/test/lisp/emacs-lisp/future-interactive-tests.el
@@ -0,0 +1,38 @@
+;;; future-interactive-tests.el --- Tests for future-interactive.el  -*- lexical-binding: t -*-
+
+;; Copyright (C) 2021 Free Software Foundation, Inc.
+
+;; Author: Stefan Kangas <stefankangas@gmail.com>
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs is free software: you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;;; Code:
+
+(require 'ert)
+(require 'future-interactive)
+
+(defun foo (args)
+  (future-interactive "P" fundamental-mode)
+  (message "args is %s" args))
+
+(ert-deftest future-interactive-test ()
+  (should (fboundp 'foo))
+  (should (foo t)))
+
+(provide 'future-interactive-tests)
+;;; future-interactive-tests.el ends here
-- 
2.30.0