G'day Flavio, I'm doing some intensive SpanSet stuff and I'm thinking you might be able to answer a couple of questions:
I'm trying to get next/previous spans from a given DateTime. I'm defining next/previous as the event who started before or after $dt. Where it ends doesn't matter, even if we're still in the middle of the event. To get the 'next' I'm intersecting with a span starting at $dt and ending at +inf. Then I get $iterator->next. I return it unless the spanset contains $dt. If it does then I return $iterator->next. This seems a lot to do to get the next span after a particular $dt. However, to get the previous is even worse! Once again I intersect with -inf to $dt. Then if the spanset contains $dt, I get the max of the complement of the intersection. This is the start of the span I want. Now to get then end of it, I can't see any other way than to intersect the original span with $dt to +inf. Which seems like craziness to me! If we're not in the middle of a span, it goes on! First I get the max of the -inf to $dt spanset intersection. That's the end of the span I want, lets call that $dt2. I then get the max of the complement of -inf to $dt2, that's the start of the span. All the above takes time. Seconds in fact! Surely there's a better way ... I'd really like to have $spanset->next_span($dt) and $spanset->previous_span($dt) but if there's some way to do it myself that is better than what I'm doing I'd love to know. Thanks and Cheers! Rick Measham
