From: Zefram <zefram@fysh.org>
To: 21903@debbugs.gnu.org
Subject: bug#21903: date->string duff ISO 8601 negative years
Date: Fri, 13 Nov 2015 14:01:57 +0000 [thread overview]
Message-ID: <20151113140157.GN13455@fysh.org> (raw)
The date->string function from (srfi srfi-19), used on ISO 8601 formats
"~1", "~4" and "~5", for years preceding AD 1, has an off-by-one error:
scheme@(guile-user)> (use-modules (srfi srfi-19))
scheme@(guile-user)> (date->string (julian-day->date 0 0) "~4")
$1 = "-4714-11-24T12:00:00Z"
The date in question, the JD epoch, is 24 November 4714 BC (in the
proleptic Gregorian calendar). In ISO 8601 format, that year is properly
represented as "-4713", not "-4714", because ISO 8601 uses the AD era
exclusively. 4714 BC = AD -4713.
-zefram
next reply other threads:[~2015-11-13 14:01 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-13 14:01 Zefram [this message]
2017-04-20 0:09 ` bug#21903: date->string duff ISO 8601 negative years Zefram
2018-10-20 22:33 ` Mark H Weaver
2018-10-21 0:40 ` Mark H Weaver
2018-10-21 4:01 ` Mark H Weaver
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