Commit 4b8683c7 authored by Glenn Morris's avatar Glenn Morris
Browse files

(calendar-time-zone-daylight-rules): Simplify.

(calendar-dst-find-data, calendar-daylight-time-offset)
(calendar-standard-time-zone-name, calendar-daylight-time-zone-name)
(calendar-daylight-savings-starts-time)
(calendar-daylight-savings-ends-time): Use cadr, nth.
parent c8ca95dd
......@@ -31,6 +31,12 @@
(ethiopic-calendar-month-name-array, ethiopic-name): Add doc strings.
(coptic-prompt-for-date): Move definition before use.
 
* calendar/cal-dst.el (calendar-time-zone-daylight-rules): Simplify.
(calendar-dst-find-data, calendar-daylight-time-offset)
(calendar-standard-time-zone-name, calendar-daylight-time-zone-name)
(calendar-daylight-savings-starts-time)
(calendar-daylight-savings-ends-time): Use cadr, nth.
* calendar/cal-french.el (french-calendar-epoch)
(calendar-goto-french-date): Doc fix.
(french-calendar-month-name-array)
......
......@@ -154,10 +154,10 @@ Return nil if no such transition can be found."
;; Heuristic: probe the time zone offset in the next three calendar
;; quarters, looking for a time zone offset different from TIME.
(while (and quarters (eq time-utc-diff hi-utc-diff))
(setq hi (cons (+ (car time) (* (car quarters) quarter-multiple)) 0))
(setq hi-zone (current-time-zone hi))
(setq hi-utc-diff (car hi-zone))
(setq quarters (cdr quarters)))
(setq hi (cons (+ (car time) (* (car quarters) quarter-multiple)) 0)
hi-zone (current-time-zone hi)
hi-utc-diff (car hi-zone)
quarters (cdr quarters)))
(and
time-utc-diff
hi-utc-diff
......@@ -224,34 +224,31 @@ The result has the proper form for `calendar-daylight-savings-starts'."
(prevday-sec (- -1 utc-diff)) ;; last sec of previous local day
(year (1+ y)))
;; Scan through the next few years until only one rule remains.
(while
(let ((rules candidate-rules)
new-rules)
(while
(let*
((rule (car rules))
(date
;; The following is much faster than
;; (calendar-absolute-from-gregorian (eval rule)).
(cond ((eq (car rule) 'calendar-nth-named-day)
(eval (cons 'calendar-nth-named-absday (cdr rule))))
((eq (car rule) 'calendar-gregorian-from-absolute)
(eval (car (cdr rule))))
(t (let ((g (eval rule)))
(calendar-absolute-from-gregorian g))))))
(or (equal
(current-time-zone
(calendar-time-from-absolute date prevday-sec))
(current-time-zone
(calendar-time-from-absolute (1+ date) prevday-sec)))
(setq new-rules (cons rule new-rules)))
(setq rules (cdr rules))))
;; If no rules remain, just use the first candidate rule;
;; it's wrong in general, but it's right for at least one year.
(setq candidate-rules (if new-rules (nreverse new-rules)
(list (car candidate-rules))))
(setq year (1+ year))
(cdr candidate-rules)))
(while (let ((rules candidate-rules)
new-rules)
(dolist (rule rules)
(let ((date
;; The following is much faster than
;; (calendar-absolute-from-gregorian (eval rule)).
(cond ((eq (car rule) 'calendar-nth-named-day)
(eval (cons 'calendar-nth-named-absday
(cdr rule))))
((eq (car rule) 'calendar-gregorian-from-absolute)
(eval (cadr rule)))
(t (calendar-absolute-from-gregorian
(eval rule))))))
(or (equal
(current-time-zone
(calendar-time-from-absolute date prevday-sec))
(current-time-zone
(calendar-time-from-absolute (1+ date) prevday-sec)))
(setq new-rules (cons rule new-rules)))))
;; If no rules remain, just use the first candidate rule;
;; it's wrong in general, but it's right for at least one year.
(setq candidate-rules (if new-rules (nreverse new-rules)
(list (car candidate-rules)))
year (1+ year))
(cdr candidate-rules)))
(car candidate-rules)))
;; TODO it might be better to extract this information directly from
......@@ -265,7 +262,7 @@ for `calendar-current-time-zone'."
(let* ((t0 (or time (current-time)))
(t0-zone (current-time-zone t0))
(t0-utc-diff (car t0-zone))
(t0-name (car (cdr t0-zone))))
(t0-name (cadr t0-zone)))
(if (not t0-utc-diff)
;; Little or no time zone information is available.
(list nil nil t0-name t0-name nil nil nil nil)
......@@ -277,7 +274,7 @@ for `calendar-current-time-zone'."
;; Use heuristics to find daylight saving parameters.
(let* ((t1-zone (current-time-zone t1))
(t1-utc-diff (car t1-zone))
(t1-name (car (cdr t1-zone)))
(t1-name (cadr t1-zone))
(t1-date-sec (calendar-absolute-from-time t1 t0-utc-diff))
(t2-date-sec (calendar-absolute-from-time t2 t1-utc-diff))
;; TODO When calendar-dst-check-each-year-flag is non-nil,
......@@ -374,34 +371,34 @@ For example, -300 for New York City, -480 for Los Angeles."
:group 'calendar-dst)
(defcustom calendar-daylight-time-offset
(or (car (cdr calendar-current-time-zone-cache)) 60)
(or (cadr calendar-current-time-zone-cache) 60)
"Number of minutes difference between daylight saving and standard time.
If the locale never uses daylight saving time, set this to 0."
:type 'integer
:group 'calendar-dst)
(defcustom calendar-standard-time-zone-name
(or (car (nthcdr 2 calendar-current-time-zone-cache)) "EST")
(or (nth 2 calendar-current-time-zone-cache) "EST")
"Abbreviated name of standard time zone at `calendar-location-name'.
For example, \"EST\" in New York City, \"PST\" for Los Angeles."
:type 'string
:group 'calendar-dst)
(defcustom calendar-daylight-time-zone-name
(or (car (nthcdr 3 calendar-current-time-zone-cache)) "EDT")
(or (nth 3 calendar-current-time-zone-cache) "EDT")
"Abbreviated name of daylight saving time zone at `calendar-location-name'.
For example, \"EDT\" in New York City, \"PDT\" for Los Angeles."
:type 'string
:group 'calendar-dst)
(defcustom calendar-daylight-savings-starts-time
(or (car (nthcdr 6 calendar-current-time-zone-cache)) 120)
(or (nth 6 calendar-current-time-zone-cache) 120)
"Number of minutes after midnight that daylight saving time starts."
:type 'integer
:group 'calendar-dst)
(defcustom calendar-daylight-savings-ends-time
(or (car (nthcdr 7 calendar-current-time-zone-cache))
(or (nth 7 calendar-current-time-zone-cache)
calendar-daylight-savings-starts-time)
"Number of minutes after midnight that daylight saving time ends."
:type 'integer
......
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