From 1d3800a7cd2be55d5bf2ac0ba6ef8502161da97b Mon Sep 17 00:00:00 2001
From: Arun Isaac
Date: Sun, 19 Jun 2022 15:46:20 +0530
Subject: Hook undo stroke into Emacs' undo system.

* thogai.el (thogai-process-stroke): Hook undo stroke into Emacs' undo
system.
---
 thogai.el | 21 ++++++---------------
 1 file changed, 6 insertions(+), 15 deletions(-)

diff --git a/thogai.el b/thogai.el
index 1fc350f..2a4fa57 100644
--- a/thogai.el
+++ b/thogai.el
@@ -450,24 +450,15 @@ STROKES is injected first."
 Process the most recent stroke, and insert its translation or
 execute a command.  STROKE-RING is the ring representing the
 current state, and should typically be `thogai-stroke-ring'."
+  (undo-boundary)
   (if (string= (ring-ref stroke-ring 0) "*")
       ;; Special case to handle the undo operation
       (progn
-        ;; Drop the "*" stroke from the state ring.
-        (ring-remove stroke-ring 0)
-        (let ((matched-strokes
-               (or (thogai-longest-match (reverse (ring-elements stroke-ring)))
-                   (list (ring-ref stroke-ring 0)))))
-          ;; Reverse the previous group of strokes.
-          (thogai-reverse-strokes matched-strokes)
-          ;; Re-insert the previous group of strokes except for the
-          ;; newest stroke.
-          (pcase (reverse matched-strokes)
-            (`(,_ . ,other-strokes)
-             (thogai-inject-strokes (reverse other-strokes)
-                                    (make-ring (length other-strokes))))))
-        ;; Remove the newest stroke from the state ring.
-        (ring-remove stroke-ring 0))
+        (undo-only)
+        ;; Drop the "*" stroke and the stroke that was just undone.
+        (dotimes (i 2)
+          (unless (zerop (ring-length stroke-ring))
+            (ring-remove stroke-ring 0))))
     (let ((matched-strokes
            (thogai-longest-match (reverse (ring-elements stroke-ring)))))
       ;; Delete translation for earlier strokes that are captured by
-- 
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