Re: What am I not understanding about DateTime::SpanSet::intersects()?

2008/12/13 Elliot Shank <[email protected]>:
> Flavio S. Glock wrote:
>>
>> The intersects() method returns undef when it can't decide if there is
>> an intersection.
>
> But why can't it decide and how can I get it to?

Proving that two unbounded (infinite) recurrences intersect is
possible, but it is *really* difficult to implement a general case.

You can help it decide by being more specific about the time range.

If you specify a span, it will calculate if there is an intersection
for that specific span:

my $span_3 = DateTime::Span->from_datetimes( start =>
DateTime->new(year=>2001), before => DateTime->new(year=>2002) );
say 'span set intersected in 2001: ',
$span_set_1->intersection($span_set_2)->intersects($span_3) ? 'yes' :
'no';
# span set intersected in 2001: yes

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