Re: date

[Katsumi Yamaoka <yamaoka@ga.sony.co.jp>]

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>>>>> In <28n287qjtk.fsf@kchisa.ga.sony.co.jp> 
>>>>>	Katsumi Yamaoka <yamaoka@ga.sony.co.jp> wrote:

KY> The last argument for encode-time() must be TZ. However, the last
KY> element of list from parse-time-string() is nil. I wonder the number
KY> of ellements from parse-time-string() exceeds right one by one.

KY> And one another thing. When we calculate UT in article-make-date-line(),
KY> only to input zero to TZ don't make the right value.

By the way, there are some Emacsen, which depends on OS and have the
BUG that TZ of the last argument is ignored by encode-time().

(current-time-string (encode-time 56 34 14 11 9 1998 32400))
	"Fri Sep 11 14:34:56 1998"

(current-time-string (encode-time 56 34 12 11 9 1998 0))
	"Fri Sep 11 14:34:56 1998"  <-- ???

I certified that they have the problem.
	Any Emacsen on NEWSOS4
        Meadow 1.01 on Windows NT

So I tried to make a program that replaces encode-time() to the
function, which returnes correct value.

[-- Attachment #2: revised-encode-time.el --]
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(if (fboundp 'original-broken-encode-time)
    nil
  (if (equal (encode-time 0 0 0 1 1 2001 0)
	     (encode-time 0 0 0 1 1 2001 43200))
      (fset 'original-broken-encode-time (symbol-function 'encode-time))))

(defun revised-encode-time (&rest args)
  "Convert SECOND, MINUTE, HOUR, DAY, MONTH, YEAR and ZONE to internal time.
This is the reverse operation of `decode-time', which see.
ZONE defaults to the current time zone rule.  This can
be a string (as from `set-time-zone-rule'), or it can be a list
\(as from `current-time-zone') or an integer (as from `decode-time')
applied without consideration for daylight savings time.

You can pass more than 7 arguments; then the first six arguments
are used as SECOND through YEAR, and the *last* argument is used as ZONE.
The intervening arguments are ignored.
This feature lets (apply 'encode-time (decode-time ...)) work.

Out-of-range values for SEC, MINUTE, HOUR, DAY, or MONTH are allowed;
for example, a DAY of 0 means the day preceding the given month.
Year numbers less than 100 are treated just like other year numbers.
If you want them to stand for years in this century, you must do that yourself.
"
  (let* ((len (length args))
	 (tz (if (> len 6) (nth (1- len) args)))
	 (time (apply 'original-broken-encode-time args))
	 ms ls)
    (if (numberp tz)
	(progn
	  (setq ms (car time)
		ls (- (car (cdr time)) tz))
	  (cond ((< ls 0)
		 (list (1- ms) (+ ls 65536)))
		((> ls 65535)
		 (list (1+ ms) (- ls 65536)))
		(t
		 (list ms ls))))
      time)))

(if (fboundp 'original-broken-encode-time)
    (fset 'encode-time 'revised-encode-time))

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-- 
Katsumi Yamaoka <yamaoka@ga.sony.co.jp>