; 'holiday-float': Improve documentation of edge case

When MONTH DAY falls on DAYNAME the holiday may be closer to MONTH DAY
than expected.  Describe this situation in the function's doc string.
(Bug#00000)

* lisp/calendar/holidays.el (holiday-float): Improve documentation.

1 files changed, 11 insertions, 4 deletions

diff --git a/lisp/calendar/holidays.el b/lisp/calendar/holidays.el
index 3acaf9b91e2..696a5b50aa1 100644
--- a/lisp/calendar/holidays.el
+++ b/lisp/calendar/holidays.el
@@ -654,10 +654,17 @@ STRING)).  Returns nil if it is not visible in the current calendar window."
 
 (defun holiday-float (month dayname n string &optional day)
   "Holiday called STRING on the Nth DAYNAME after/before MONTH DAY.
-DAYNAME=0 means Sunday, DAYNAME=1 means Monday, and so on.
-If N>0, use the Nth DAYNAME after MONTH DAY.
-If N<0, use the Nth DAYNAME before MONTH DAY.
-DAY defaults to 1 if N>0, and MONTH's last day otherwise.
+DAYNAME = 0 means Sunday, DAYNAME = 1 means Monday, and so on.  DAY
+defaults to 1 if N > 0, and MONTH's last day otherwise.
+
+If N > 0, use the Nth DAYNAME after MONTH DAY.
+If N < 0, use the Nth DAYNAME before MONTH DAY.
+
+When MONTH DAY falls on DAYNAME, the holiday will be |N|-1 weeks before
+or after MONTH DAY.  For example, with N = +1 (-1) the holiday falls on
+MONTH DAY, and with N = +2 (-2) the holiday falls 1 week after (before)
+MONTH DAY.
+
 If the holiday is visible in the calendar window, returns a
 list (((month day year) STRING)).  Otherwise returns nil."
   ;; This is messy because the holiday may be visible, while the date