From: Campbell Barton <ideasman42@gmail.com>
To: Emacs developers <emacs-devel@gnu.org>
Subject: Support for undo-amalgamate in a version of the atomic-change-group macro (with patch)
Date: Fri, 29 Oct 2021 12:48:24 +1100 [thread overview]
Message-ID: <CAEcf3NwgG2BY_0m2ui7WtiDgcVx68CX0REv4MUSQDRQXohF6qA@mail.gmail.com> (raw)
[-- Attachment #1: Type: text/plain, Size: 569 bytes --]
Hi, there have been a handful of times I've needed to treat multiple
actions as a single action,
others too (see stackoverflow question [0]).
While this is supported using change groups, the resulting macro ends
up being nearly identical to the existing `atomic-change-group' macro.
The only difference is a call to undo-amalgamate-change-group.
Attached a patch to add `atomic-change-group-undo-amalgamate' so
packages don't need to use a modified copy of this macro.
[0]: https://emacs.stackexchange.com/questions/7558/how-to-collapse-undo-history
--
- Campbell
[-- Attachment #2: emacs-atomic-change-group-undo-amalgamate.diff --]
[-- Type: text/x-patch, Size: 2306 bytes --]
commit 5cf79a19dac5187b6e8f4f6c3798d0f348eff89c
Author: Campbell Barton <ideasman42@gmail.com>
Date: Fri Oct 29 12:33:29 2021 +1100
Add a version of atomic-change-group that amalgamates undo steps
diff --git a/lisp/subr.el b/lisp/subr.el
index 39676249cd..4d2ca0b953 100644
--- a/lisp/subr.el
+++ b/lisp/subr.el
@@ -3490,15 +3490,8 @@ y-or-n-p
\f
;;; Atomic change groups.
-(defmacro atomic-change-group (&rest body)
- "Like `progn' but perform BODY as an atomic change group.
-This means that if BODY exits abnormally,
-all of its changes to the current buffer are undone.
-This works regardless of whether undo is enabled in the buffer.
-
-This mechanism is transparent to ordinary use of undo;
-if undo is enabled in the buffer and BODY succeeds, the
-user can undo the change normally."
+(defmacro atomic-change-group-1 (undo-amalgamate &rest body)
+ "Implementation of `atomic-change-group' & `atomic-change-group-amalgamate'."
(declare (indent 0) (debug t))
(let ((handle (make-symbol "--change-group-handle--"))
(success (make-symbol "--change-group-success--")))
@@ -3519,9 +3512,28 @@ atomic-change-group
;; Either of these functions will disable undo
;; if it was disabled before.
(if ,success
- (accept-change-group ,handle)
+ (progn
+ (accept-change-group ,handle)
+ (when ,undo-amalgamate
+ (undo-amalgamate-change-group ,handle)))
(cancel-change-group ,handle))))))
+(defmacro atomic-change-group (&rest body)
+ "Like `progn' but perform BODY as an atomic change group.
+This means that if BODY exits abnormally,
+all of its changes to the current buffer are undone.
+This works regardless of whether undo is enabled in the buffer.
+
+This mechanism is transparent to ordinary use of undo;
+if undo is enabled in the buffer and BODY succeeds, the
+user can undo the change normally."
+ `(atomic-change-group-1 nil ,@body))
+
+(defmacro atomic-change-group-undo-amalgamate (&rest body)
+ "A version of `atomic-change-group' that amalgamates
+the change groups undo data."
+ `(atomic-change-group-1 t ,@body))
+
(defun prepare-change-group (&optional buffer)
"Return a handle for the current buffer's state, for a change group.
If you specify BUFFER, make a handle for BUFFER's state instead.
next reply other threads:[~2021-10-29 1:48 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-29 1:48 Campbell Barton [this message]
2021-11-01 17:43 ` Support for undo-amalgamate in a version of the atomic-change-group macro (with patch) Stefan Monnier
2021-11-02 1:04 ` Campbell Barton
2021-11-02 2:14 ` Stefan Monnier
2021-11-02 2:14 ` Campbell Barton
2021-11-07 8:45 ` Campbell Barton
2021-11-07 13:21 ` Stefan Monnier
2021-11-07 23:09 ` Campbell Barton
2021-11-07 23:29 ` Campbell Barton
2021-11-08 4:39 ` Stefan Monnier
2021-11-08 4:46 ` Lars Ingebrigtsen
2021-11-08 5:41 ` Campbell Barton
2021-11-08 13:40 ` Stefan Monnier
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