       (message "Error: both current coding and major-mode are nil."))))
 
 ;; 確認なしでバッファの削除
-(defun kui/kill-buffer-with-no-confirmation ()
+(defun kui/kill-buffer-without-interaction ()
+  "Kill the current buffer without interaction"
   (interactive)
   (kill-buffer nil))
-(global-set-key "\C-xk" 'kui/kill-buffer-with-no-confirmation)
+(global-set-key "\C-xk" 'kui/kill-buffer-without-interaction)
 
 ;; フルスクリーン状態をトグル
 (defun kui/toggle-fullscreen ()
   "Toggle full screen"
   (interactive)
   (cond
-   ((eq window-system 'x) ;; x window system
+   ((eq window-system 'x) ;; when x window system
     (set-frame-parameter
      nil 'fullscreen
-     (when (not (frame-parameter nil 'fullscreen)) 'fullboth)))
+     (if (not (frame-parameter nil 'fullscreen)) 'fullboth)))
    (t ;; default
     (message "window-system:%s not supported" (symbol-name window-system)))))
 (global-set-key [M-return] 'kui/toggle-fullscreen)

  (interactive)
  (comment-or-uncomment-region (line-beginning-position)
                               (line-end-position)))
(global-set-key (kbd "C-;") 'kui/comment-or-uncomment-current-line)

;; マジックコメント挿入
(defun kui/insert-magic-comment ()


;; require の代わりに使う
(defun kui/autoload-if-exist (function file &optional docstring interactive type)
  "do `(autoload FUNCTION FILE)` if FILE exist"
  (if (locate-library file)
      (let () (autoload function file docstring interactive type) t)))

;; 現在の行をコメントアウト
(defun kui/comment-or-uncomment-current-line ()
