> Duration of 0 makes much more sense to me as a duration value of an > instantaneous event. > > > Well, I certainly agree that an instantaneous event cannot be an > > interval event. However, there is some confusion in (my mind at least) > > using the various DV_DURATIONS in History. But the biggest issue I have > > is in dealing with the fact that an Interval Event has one and only one > > DV_DURATION. DV_DURATION can never be Void. It MUST return a valid ISO > > Date_Time value.
I'm not really understanding the problem - HISTORY has a set of EVENT's (base class) - where the event can either be a POINT_EVENT (instantaneous, no 'width' attribute in the class definition at all! therefore meeting the requirement that width is void), or it can be an INTERVAL_EVENT (this class does have a width attribute of type DV_DURATION, yet semantically can't have a width of 0 duration). It is correct that Interval Event has one and only one DV_DURATION - to represent an instantaneous event one has to _not_ use the interval event class, instead using the point event class. Andrew
