Mewのサマリモードで、タイムゾーンを考慮した日時を表示する

mew-summary-form-considering-timezone.el

;; mew summary date/time considering timezone
;; http://permalink.gmane.org/gmane.mail.mew.general.japanese/2355
(defun mew-summary-form-time-z ()
  "A function to return a message time, HH:MM"
  (let ((s (MEW-DATE)))
    (setq s (timezone-make-date-arpa-standard
             (if (or (string= s "")
                     (not (string-match mew-time-rfc-regex s)))
                 (mew-time-ctz-to-rfc
                  (mew-file-get-time (mew-expand-folder (MEW-FLD) (MEW-NUM))))
               s)))
    (if (string-match mew-time-rfc-regex s)
        (format "%02d:%02d"
                (or (mew-time-rfc-hour) 0)
                (or (mew-time-rfc-min)  0))
      "00:00")))

(defun mew-summary-form-date-z ()
  "A function to return a date, MM/DD."
  (let ((s (MEW-DATE)))
    (setq s (timezone-make-date-arpa-standard
             (if (or (string= s "")
                     (not (string-match mew-time-rfc-regex s)))
                 (mew-time-ctz-to-rfc
                  (mew-file-get-time (mew-expand-folder (MEW-FLD) (MEW-NUM))))
               s)))
    (if (string-match mew-time-rfc-regex s)
        (format "%02d/%02d"
                (mew-time-mon-str-to-int (mew-time-rfc-mon))
                (mew-time-rfc-day))
      "")))

(defun mew-summary-form-time-zone ()
  "A function to return a message date timezone, +ZZZZ."
  (let ((s (MEW-DATE)))
    (when (or (string= s "")
              (not (string-match mew-time-rfc-regex s)))
      (setq s (mew-time-ctz-to-rfc
               (mew-file-get-time (mew-expand-msg (MEW-FLD) (MEW-NUM))))))
    (if (string-match mew-time-rfc-regex s)
        (format "%05s"
                (if (match-beginning 9)
                    (let ((tmzn (substring s (match-beginning 9) (match-end 9)))
                          int)
                      (cond
                       ((string-match "^[-+][0-9]+$" tmzn)
                        tmzn)
                       ((setq int (mew-time-tmzn-str-to-int tmzn))
                        (format "%s00" int))
                       (t "+????")))
                  "+????"))
      "+????")))

;; use above
;; (setq mew-summary-form '(type (4 year) "/" (5 date-z) " " (5 time-z) "(" (5 time-zone) ") " (60 from) "|" t (0 subj)))

これを参考に mew の環境を整えました。ありがとうございます。
使っていてバグに気付きました。
(mew-expand-folder (MEW-FLD) (MEW-NUM)) が2箇所ありますが、これは
(mew-expand-msg (MEW-FLD) (MEW-NUM)) の間違いだと思います。

大変便利です。emacs-27.2 にして気づいたのですが、timezone.el を require する必要があるようです。

(require 'timezone)