+(defconst parse-time-iso8601-regexp
+ (let* ((dash "-?")
+ (colon ":?")
+ (4digit "\\([0-9][0-9][0-9][0-9]\\)")
+ (2digit "\\([0-9][0-9]\\)")
+ (date-fullyear 4digit)
+ (date-month 2digit)
+ (date-mday 2digit)
+ (time-hour 2digit)
+ (time-minute 2digit)
+ (time-second 2digit)
+ (time-secfrac "\\(\\.[0-9]+\\)?")
+ (time-numoffset (concat "[-+]\\(" time-hour "\\):" time-minute))
+ (time-offset (concat "Z" time-numoffset))
+ (partial-time (concat time-hour colon time-minute colon time-second
+ time-secfrac))
+ (full-date (concat date-fullyear dash date-month dash date-mday))
+ (full-time (concat partial-time time-offset))
+ (date-time (concat full-date "T" full-time)))
+ (list (concat "^" full-date)
+ (concat "T" partial-time)
+ (concat "Z" time-numoffset)))
+ "List of regular expressions matching ISO 8601 dates.
+1st regular expression matches the date.
+2nd regular expression matches the time.
+3rd regular expression matches the (optional) timezone specification.")
+
+(defun parse-iso8601-time-string (date-string)
+ (let* ((date-re (nth 0 parse-time-iso8601-regexp))
+ (time-re (nth 1 parse-time-iso8601-regexp))
+ (tz-re (nth 2 parse-time-iso8601-regexp))
+ re-start
+ time seconds minute hour fractional-seconds
+ day month year day-of-week dst tz)
+ ;; We need to populate 'time' with
+ ;; (SEC MIN HOUR DAY MON YEAR DOW DST TZ)
+
+ ;; Nobody else handles iso8601 correctly, let's do it ourselves.
+ (when (string-match date-re date-string re-start)
+ (setq year (string-to-number (match-string 1 date-string))
+ month (string-to-number (match-string 2 date-string))
+ day (string-to-number (match-string 3 date-string))
+ re-start (match-end 0))
+ (when (string-match time-re date-string re-start)
+ (setq hour (string-to-number (match-string 1 date-string))
+ minute (string-to-number (match-string 2 date-string))
+ seconds (string-to-number (match-string 3 date-string))
+ fractional-seconds (string-to-number (or
+ (match-string 4 date-string)
+ "0"))
+ re-start (match-end 0))
+ (when (string-match tz-re date-string re-start)
+ (setq tz (match-string 1 date-string)))
+ (setq time (list seconds minute hour day month year day-of-week dst tz))))
+
+ ;; Fall back to having Gnus do fancy things for us.
+ (when (not time)
+ (setq time (parse-time-string date-string)))
+
+ (and time
+ (apply 'encode-time time))))
+