Emacs(Elisp): return t once in a day. 1日一回tを返すelispです。

is-once-in-a-day.el

;;; ------------------------------------------------------------
;;; 1日1回のチェック
;; gist-description: Emacs(Elisp): return t once in a day. 1日一回tを返すelispです。
;; gist-id: 33e072cea6aa96a19f58
;; gist-name: is-once-in-a-day.el
;; gist-private: nil

(defun is-once-in-a-day ()
  "Is once in a day."
  (interactive)
  (let* ((target-file (concat dotfiles-dir ".is-once-in-a-day"))
         (target-update-at (if (file-exists-p target-file)
                               (nth 5 (file-attributes target-file))
                             (append-to-file "" nil target-file)))
         (criteria-time (apply 'encode-time 0 0 0 (nthcdr 3 (decode-time))))
         (ftime (if target-update-at
                    (float-time (time-subtract criteria-time target-update-at))
                  nil)))
    (cond ((and target-update-at ftime (> ftime 0))
           (delete-file target-file)
           (append-to-file "." nil target-file)
           t)
          ((and target-update-at ftime (< ftime 0))
           nil)
          ((not target-update-at)
           (delete-file target-file)
           (append-to-file "." nil target-file)
           t))))