calendar: Clarify week-number with year ends

diff --git a/basis/calendar/calendar-docs.factor b/basis/calendar/calendar-docs.factor
index b577c77abbc782734f2bdccfea41e58f4d60a199..b7f99d15488c13f1156e15182e5e31ad676a261c 100644 (file)
--- a/basis/calendar/calendar-docs.factor
+++ b/basis/calendar/calendar-docs.factor
@@ -415,7 +415,7 @@ HELP: day-of-year
 
 HELP: week-number
 { $values { "timestamp" timestamp } { "[1,53]" integer } }
-{ $description "Calculates the ISO 8601 week number from 1 to 53 (leap years). See " { $snippet "https://en.wikipedia.org/wiki/ISO_week_date" } }
+{ $description "Calculates the ISO 8601 week number from 1 to 53 (leap years). Weeks start on Monday and end on Sunday. The end of December can sometimes be the first week of the next year and January can be the last week number of the previous year. See " { $snippet "https://en.wikipedia.org/wiki/ISO_week_date" } }
 { $examples
     "Last day of 2018 is already in the first week of 2019."
     { $example "USING: calendar prettyprint ;"