[elpa] externals/compat 2f3813bf78: compat-27: Add major-mode-suspend and major-mode-restore

[ELPA Syncer]

branch: externals/compat
commit 2f3813bf78ec129119b86076e7d43f0a30e4eb39
Author: Daniel Mendler <mail@daniel-mendler.de>
Commit: Daniel Mendler <mail@daniel-mendler.de>

    compat-27: Add major-mode-suspend and major-mode-restore
---
 NEWS.org        |  1 +
 compat-27.el    | 31 +++++++++++++++++++++++++++++++
 compat-macs.el  |  7 +++++--
 compat-tests.el | 13 +++++++++++++
 compat.texi     | 25 ++++++++++++++++++++-----
 5 files changed, 70 insertions(+), 7 deletions(-)

diff --git a/NEWS.org b/NEWS.org
index 0feece8f92..f1d75124ec 100644
--- a/NEWS.org
+++ b/NEWS.org
@@ -8,6 +8,7 @@
 - compat-25: Add ~save-mark-and-excursion~.
 - compat-26: Add ~region-bounds~.
 - compat-27: Add ~date-ordinal-to-time~.
+- compat-27: Add ~major-mode-suspend~ and ~major-mode-restore~.
 - compat-27: Add ~make-decoded-time~.
 - compat-27: Add ~minibuffer-history-value~.
 - compat-27: Add ~ring-resize~.
diff --git a/compat-27.el b/compat-27.el
index 01af37dee5..6f940ce9ac 100644
--- a/compat-27.el
+++ b/compat-27.el
@@ -280,6 +280,37 @@ return nil."
         (setq tail tail-cdr))))
   alist)
 
+(compat-defvar major-mode--suspended nil ;; <compat-tests:major-mode-suspend>
+  "Suspended major mode."
+  :local permanent)
+
+(compat-defun major-mode-suspend () ;; <compat-tests:major-mode-suspend>
+  "Exit current major mode, remembering it."
+  (let* ((prev-major-mode (or major-mode--suspended
+                              (unless (eq major-mode 'fundamental-mode)
+                                major-mode))))
+    (kill-all-local-variables)
+    (setq-local major-mode--suspended prev-major-mode)))
+
+(compat-defun major-mode-restore (&optional avoided-modes) ;; 
<compat-tests:major-mode-suspend>
+  "Restore major mode earlier suspended with `major-mode-suspend'.
+If there was no earlier suspended major mode, then fallback to `normal-mode',
+though trying to avoid AVOIDED-MODES."
+  (if major-mode--suspended
+      (funcall (prog1 major-mode--suspended
+                 (kill-local-variable 'major-mode--suspended)))
+    (let ((auto-mode-alist
+           (let ((alist (copy-sequence auto-mode-alist)))
+             (dolist (mode avoided-modes)
+               (setq alist (rassq-delete-all mode alist)))
+             alist))
+          (magic-fallback-mode-alist
+           (let ((alist (copy-sequence magic-fallback-mode-alist)))
+             (dolist (mode avoided-modes)
+               (setq alist (rassq-delete-all mode alist)))
+             alist)))
+      (normal-mode))))
+
 ;;;; Defined in simple.el
 
 (compat-guard (not (fboundp 'decoded-time-second))
diff --git a/compat-macs.el b/compat-macs.el
index b3edaf6a57..addef5ecd1 100644
--- a/compat-macs.el
+++ b/compat-macs.el
@@ -234,8 +234,11 @@ definition is generated.
           ,@(cond
              ((eq local 'permanent)
               `((put ',name 'permanent-local t)))
-             (local
-              `((make-variable-buffer-local ',name)))))))))
+             ((eq local t)
+              `((make-variable-buffer-local ',name)))
+             ((not local)
+              nil)
+             (t (error "Invalid value for :local"))))))))
 
 (provide 'compat-macs)
 ;;; compat-macs.el ends here
diff --git a/compat-tests.el b/compat-tests.el
index e221f8534f..e98d1fc94a 100644
--- a/compat-tests.el
+++ b/compat-tests.el
@@ -2809,5 +2809,18 @@
     (should-equal 4 (count-sentences (point-min) (point-max)))
     (should-equal 2 (count-sentences 16 50))))
 
+(ert-deftest major-mode-suspend ()
+  (with-temp-buffer
+    (text-mode)
+    (should sentence-end-double-space)
+    (setq-local sentence-end-double-space nil)
+    (major-mode-suspend)
+    (should-not line-spacing)
+    (prog-mode)
+    (should-equal major-mode 'prog-mode)
+    (major-mode-restore)
+    (should sentence-end-double-space)
+    (should-equal major-mode 'text-mode)))
+
 (provide 'compat-tests)
 ;;; compat-tests.el ends here
diff --git a/compat.texi b/compat.texi
index efc88ac306..95b92a1042 100644
--- a/compat.texi
+++ b/compat.texi
@@ -952,6 +952,25 @@ The following functions and macros are implemented in Emacs
 27.1. These functions are made available by Compat on Emacs versions
 older than 27.1.
 
+@c copied from lispref/modes.texi
+@defun major-mode-suspend
+This function works like @code{fundamental-mode}, in that it kills all
+buffer-local variables, but it also records the major mode in effect,
+so that it could subsequently be restored.  This function and
+@code{major-mode-restore} (described next) are useful when you need to
+put a buffer under some specialized mode other than the one Emacs
+chooses for it automatically, but would also like to be able to switch
+back to the original mode later.
+@end defun
+
+@c copied from lispref/modes.texi
+@defun major-mode-restore &optional avoided-modes
+This function restores the major mode recorded by
+@code{major-mode-suspend}.  If no major mode was recorded, this
+function calls @code{normal-mode}, but tries to force it not to choose
+any modes in @var{avoided-modes}, if that argument is non-@code{nil}.
+@end defun
+
 @c copied from lispref/sequences.texi
 @defun ring-resize ring size
 Set the size of @var{ring} to @var{size}.  If the new size is smaller,
@@ -1479,8 +1498,6 @@ The macro @code{with-suppressed-warnings}.
 @item
 Support for @code{condition-case} to handle t.
 @item
-The functions @code{major-mode-suspend} and @code{major-mode-restore}.
-@item
 The function @code{file-system-info}.
 @item
 The function @code{group-name}.
@@ -2034,7 +2051,7 @@ Support for @code{:interactive} argument to 
@code{define-minor-mode} and
 Support for @code{:predicate} argument to
 @code{define-globalized-minor-mode}.
 @item
-"Success handler" for @code{condition-case}.
+Support for the @code{:success} handler of @code{condition-case}.
 @item
 The function @code{benchmark-call}.
 @item
@@ -2086,8 +2103,6 @@ The function @code{max-mini-window-lines}.
 @item
 The function @code{lock-file} and @code{unlock-file}.
 @item
-The macro @code{with-window-non-dedicated}.
-@item
 Any @code{multisession} functionality.
 @end itemize