Add comments and doc strings

lisp/calendar/iso8601.el

@@ -21,6 +21,14 @@
 
 ;;; Commentary:
 
+;; For a publicly available version of the standards document, see:
+
+;; http://www.loc.gov/standards/datetime/iso-tc154-wg5_n0038_iso_wd_8601-1_2016-02-16.pdf
+
+;; The Wikipedia page on the standard is also informative:
+
+;; https://en.wikipedia.org/wiki/ISO_8601
+
 ;;; Code:
 
 (require 'time-date)

src/timefns.c

@@ -1326,6 +1326,12 @@ the TZ environment variable.  It can also be a list (as from
 `current-time-zone') or an integer (the UTC offset in seconds) applied
 without consideration for daylight saving time.
 
+To access (or alter) the elements in the time value, the
+`decoded-time-second', `decoded-time-minute', `decoded-time-hour',
+`decoded-time-day', `decoded-time-month', `decoded-time-year',
+`decoded-time-weekday', `decoded-time-dst' and `decoded-time-zone'
+accessors can be used.
+
 The list has the following nine members: SEC is an integer between 0
 and 60; SEC is 60 for a leap second, which only some operating systems
 support.  MINUTE is an integer between 0 and 59.  HOUR is an integer