GNU bug report logs - #78096
31.0.50; calendar-iso-to-absolute and %W time string format are inconsistent

Previous Next

Full log

View this message in rfc822 format

From: Andreas Schwab <schwab <at> linux-m68k.org>
To: Ihor Radchenko <yantar92 <at> posteo.net>
Cc: Stephen Berman <stephen.berman <at> gmx.net>, 78096 <at> debbugs.gnu.org
Subject: bug#78096: 31.0.50; calendar-iso-to-absolute and %W time string format are inconsistent
Date: Mon, 28 Apr 2025 18:43:18 +0200

On Apr 28 2025, Ihor Radchenko wrote:

> Stephen Berman <stephen.berman <at> gmx.net> writes:
>
>> The doc string of `format-time-string' says:
>>
>> %U is the week number starting on Sunday, %W starting on Monday,
>>  %V the week number according to ISO 8601.
>>
>> (format-time-string
>>   "%Y-%m-%d W%V"
>>   (encode-time (parse-time-string "2025-01-06 00:00")))
>> => "2025-01-06 W02"
>
> That indeed explains it - %W and %V are apparently not the same and
> `calendar-iso-to-absolute' is closer to %V.

The difference is that %V is always the same for the whole week, whereas
%V and %W roll over on 01-01 (and use 0 for a partial first week).

$ for y in $(seq 2020 2025); do date -d "$y-01-01" +"%a %U %V %W"; done
Wed 00 01 00
Fri 00 53 00
Sat 00 52 00
Sun 01 52 00
Mon 00 01 01
Wed 00 01 00

-- 
Andreas Schwab, schwab <at> linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510  2552 DF73 E780 A9DA AEC1
"And now for something completely different."

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.