> (1) In the spec, an interval value or literal must be either
> year-month or day-time. (I guess they didn't want to try to deal with
> the sticky issues of what it means to have an interval of, for
> example, seven months and three days -- since an interval has no sense
> of which seven months.)
Note that, for usability reasons, Karel some time ago try-partitioned
our intervals: year-month|day-week|hour-min-sec.
--Josh