> I wondered what you meant by that - I still do. You mean you want the
> stylesheet to detect a time at which no sessions are alive, and use that as
> a boundary between periods? What if there is no such time?

Let me try this approach, and assuming the XML source is sorted accordingly..

>You mean you want the
> stylesheet to detect a time at which no sessions are alive, and use that as
> a boundary between periods? What if there is no such time?

First element of period:  first element or first element where
period_begin does not fall within previous sibling period_begin and
period_end.

Last element of period:  last element match where period_begin falls
within previous sibling period_begin and period_end.

> What if there are several?

It shouldn't matter.


On 5/3/05, Michael Kay <mike@xxxxxxxxxxxx> wrote:
> > The challend did state that the periods listed were arbitrary
> > (unkown).  Any way to drive your solution without parameters or
> > pre-existing variables defining these periods?
>
> I wondered what you meant by that - I still do. You mean you want the
> stylesheet to detect a time at which no sessions are alive, and use that as
> a boundary between periods? What if there is no such time? What if there
are
> several? You need to specify the problem more precisely.
>
> Michael Kay
> http://www.saxonica.com/