+=head1 Current Time
+The epoch used in Perl 6 to represent time instants is the
+International Atomic Time - TAI - which is independent of calendars,
+timezones as well as leap seconds. Of course Perl can't go beyond the
+machine to get a real TAI value, but it should perform any
+platform-specific transformation to give you the most precise value it
+can for the TAI.
+ our Rat sub time()
+Returns a TAI epoch value for the current time.
Shouldn't the result type of time() be an "Instant" object (Instant and Duration
are defined in S02) rather than a "Rat"?
Temporal routines should always be using temporal types when talking about
instants or durations, not more generic types like numbers or strings except
when explicitly converting or extracting a temporal value into one of those
types, such as when displaying it.
-- Darren Duncan