Rewrite `parse-iso8601-time-string' to use `iso8601-parse'

* lisp/calendar/parse-time.el (parse-iso8601-time-string): Use
`iso8601-parse'.
(parse-time-iso8601-regexp): Remove.

1 files changed, 9 insertions, 65 deletions

diff --git a/lisp/calendar/parse-time.el b/lisp/calendar/parse-time.el
index 68d6ce05d6c..e28df97918e 100644
--- a/lisp/calendar/parse-time.el
+++ b/lisp/calendar/parse-time.el
@@ -36,6 +36,8 @@
 ;;; Code:
 
 (require 'cl-lib)
+(require 'iso8601)
+(eval-when-compile (require 'subr-x))
 
 ;; Byte-compiler warnings
 (defvar parse-time-elt)
@@ -193,75 +195,17 @@ unknown DST value is returned as -1."
                   (setf (nth (pop slots) time) new-val))))))))
     time))
 
-(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 "?"))
-         (partial-time (concat time-hour colon time-minute colon time-second
-                               time-secfrac))
-         (full-date (concat date-fullyear dash date-month dash date-mday)))
-    (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)
   "Parse an ISO 8601 time string, such as 2016-12-01T23:35:06-05:00.
 If DATE-STRING cannot be parsed, it falls back to
 `parse-time-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
-         day month year day-of-week (dst -1) 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))
-              re-start (match-end 0))
-        (when (string-match tz-re date-string re-start)
-          (setq dst nil)
-          (setq tz (if (string= "Z" (match-string 1 date-string))
-                       0  ;; UTC timezone indicated by Z
-                     (let ((tz (+
-                                (* 3600
-                                   (string-to-number
-                                    (match-string 3 date-string)))
-                                (* 60
-                                   (string-to-number
-                                    (or (match-string 4 date-string) "0"))))))
-                       (if (string= "-" (match-string 2 date-string))
-                            (- tz) tz)))))
-        (setq time (list seconds minute hour day month year day-of-week dst tz))))
-
-    ;; Fall back to having `parse-time-string' do fancy things for us.
-    (when (not time)
-      (setq time (parse-time-string date-string)))
-
-    (and time
-         (encode-time time))))
+  (when-let ((time
+              (if (iso8601-valid-p date-string)
+                  (decoded-time-set-defaults (iso8601-parse date-string))
+                ;; Fall back to having `parse-time-string' do fancy
+                ;; things for us.
+                (parse-time-string date-string))))
+    (encode-time time)))
 
 (provide 'parse-time)