add toggle-window-split

.emacs

@@ -110,3 +110,31 @@
 (global-set-key (kbd "C-d") 'duplicate-line)
 
 (put 'scroll-left 'disabled nil)
+
+(defun toggle-window-split ()
+  (interactive)
+  (if (= (count-windows) 2)
+      (let* ((this-win-buffer (window-buffer))
+             (next-win-buffer (window-buffer (next-window)))
+             (this-win-edges (window-edges (selected-window)))
+             (next-win-edges (window-edges (next-window)))
+             (this-win-2nd
+              (not (and (<= (car this-win-edges)
+                            (car next-win-edges))
+                        (<= (cadr this-win-edges)
+                            (cadr next-win-edges)))))
+             (splitter
+              (if (= (car this-win-edges)
+                     (car (window-edges (next-window))))
+                  #'split-window-horizontally
+                #'split-window-vertically)))
+        (delete-other-windows)
+        (let ((first-win (selected-window)))
+          (funcall splitter)
+          (if this-win-2nd (other-window 1))
+          (set-window-buffer (selected-window) this-win-buffer)
+          (set-window-buffer (next-window) next-win-buffer)
+          (select-window first-win)
+          (if this-win-2nd (other-window 1))))))
+
+(global-set-key (kbd "C-x |") #'toggle-window-split)