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-rw-r--r--doc/ref/srfi-modules.texi21
1 files changed, 10 insertions, 11 deletions
diff --git a/doc/ref/srfi-modules.texi b/doc/ref/srfi-modules.texi
index 95509b278..3d4415629 100644
--- a/doc/ref/srfi-modules.texi
+++ b/doc/ref/srfi-modules.texi
@@ -2383,17 +2383,6 @@ functions and variables described here are provided by
(use-modules (srfi srfi-19))
@end example
-@strong{Caution}: The current code in this module incorrectly extends
-the Gregorian calendar leap year rule back prior to the introduction
-of those reforms in 1582 (or the appropriate year in various
-countries). The Julian calendar was used prior to 1582, and there
-were 10 days skipped for the reform, but the code doesn't implement
-that.
-
-This will be fixed some time. Until then calculations for 1583
-onwards are correct, but prior to that any day/month/year and day of
-the week calculations are wrong.
-
@menu
* SRFI-19 Introduction::
* SRFI-19 Time::
@@ -2593,6 +2582,16 @@ The fields are year, month, day, hour, minute, second, nanoseconds and
timezone. A date object is immutable, its fields can be read but they
cannot be modified once the object is created.
+Historically, the Gregorian calendar was only used from the latter part
+of the year 1582 onwards, and not until even later in many countries.
+Prior to that most countries used the Julian calendar. SRFI-19 does
+not deal with the Julian calendar at all, and so does not reflect this
+historical calendar reform. Instead it projects the Gregorian calendar
+back proleptically as far as necessary. When dealing with historical
+data, especially prior to the British Empire's adoption of the Gregorian
+calendar in 1752, one should be mindful of which calendar is used in
+each context, and apply non-SRFI-19 facilities to convert where necessary.
+
@defun date? obj
Return @code{#t} if @var{obj} is a date object, or @code{#f} if not.
@end defun