NAME

       DateTime::Span - Datetime spans

SYNOPSIS

           use DateTime;
           use DateTime::Span;

           $date1 = DateTime->new( year => 2002, month => 3, day => 11 );
           $date2 = DateTime->new( year => 2003, month => 4, day => 12 );
           $set2 = DateTime::Span->from_datetimes( start => $date1, end => $date2 );
           #  set2 = 2002-03-11 until 2003-04-12

           $set = $set1->union( $set2 );         # like "OR", "insert", "both"
           $set = $set1->complement( $set2 );    # like "delete", "remove"
           $set = $set1->intersection( $set2 );  # like "AND", "while"
           $set = $set1->complement;             # like "NOT", "negate", "invert"

           if ( $set1->intersects( $set2 ) ) { ...  # like "touches", "interferes"
           if ( $set1->contains( $set2 ) ) { ...    # like "is-fully-inside"

           # data extraction
           $date = $set1->start;           # first date of the span
           $date = $set1->end;             # last date of the span

DESCRIPTION

       "DateTime::Span" is a module for handling datetime spans, otherwise known as ranges or
       periods ("from X to Y, inclusive of all datetimes in between").

       This is different from a "DateTime::Set", which is made of individual datetime points as
       opposed to a range. There is also a module "DateTime::SpanSet" to handle sets of spans.

METHODS

       •   from_datetimes

           Creates a new span based on a starting and ending datetime.

           A 'closed' span includes its end-dates:

              $span = DateTime::Span->from_datetimes( start => $dt1, end => $dt2 );

           An 'open' span does not include its end-dates:

              $span = DateTime::Span->from_datetimes( after => $dt1, before => $dt2 );

           A 'semi-open' span includes one of its end-dates:

              $span = DateTime::Span->from_datetimes( start => $dt1, before => $dt2 );
              $span = DateTime::Span->from_datetimes( after => $dt1, end => $dt2 );

           A span might have just a beginning date, or just an ending date.  These spans end, or
           start, in an imaginary 'forever' date:

              $span = DateTime::Span->from_datetimes( start => $dt1 );
              $span = DateTime::Span->from_datetimes( end => $dt2 );
              $span = DateTime::Span->from_datetimes( after => $dt1 );
              $span = DateTime::Span->from_datetimes( before => $dt2 );

           You cannot give both a "start" and "after" argument, nor can you give both an "end"
           and "before" argument.  Either of these conditions will cause the "from_datetimes()"
           method to die.

           To summarize, a datetime passed as either "start" or "end" is included in the span.  A
           datetime passed as either "after" or "before" is excluded from the span.

       •   from_datetime_and_duration

           Creates a new span.

              $span = DateTime::Span->from_datetime_and_duration(
                  start => $dt1, duration => $dt_dur1 );
              $span = DateTime::Span->from_datetime_and_duration(
                  after => $dt1, hours => 12 );

           The new "end of the set" is open by default.

       •   clone

           This object method returns a replica of the given object.

       •   set_time_zone( $tz )

           This method accepts either a time zone object or a string that can be passed as the
           "name" parameter to "DateTime::TimeZone->new()".  If the new time zone's offset is
           different from the old time zone, then the local time is adjusted accordingly.

           If the old time zone was a floating time zone, then no adjustments to the local time
           are made, except to account for leap seconds.  If the new time zone is floating, then
           the UTC time is adjusted in order to leave the local time untouched.

       •   duration

           The total size of the set, as a "DateTime::Duration" object, or as a scalar containing
           infinity.

           Also available as "size()".

       •   start

       •   end

           First or last dates in the span.

           It is possible that the return value from these methods may be a
           "DateTime::Infinite::Future" or a "DateTime::Infinite::Past"xs object.

           If the set ends "before" a date $dt, it returns $dt. Note that in this case $dt is not
           a set element - but it is a set boundary.

       •   start_is_closed

       •   end_is_closed

           Returns true if the first or last dates belong to the span ( begin <= x <= end ).

       •   start_is_open

       •   end_is_open

           Returns true if the first or last dates are excluded from the span ( begin < x < end
           ).

       •   union

       •   intersection

       •   complement

           Set operations may be performed not only with "DateTime::Span" objects, but also with
           "DateTime::Set" and "DateTime::SpanSet" objects.  These set operations always return a
           "DateTime::SpanSet" object.

               $set = $span->union( $set2 );         # like "OR", "insert", "both"
               $set = $span->complement( $set2 );    # like "delete", "remove"
               $set = $span->intersection( $set2 );  # like "AND", "while"
               $set = $span->complement;             # like "NOT", "negate", "invert"

       •   intersects

       •   contains

           These set functions return a boolean value.

               if ( $span->intersects( $set2 ) ) { ...  # like "touches", "interferes"
               if ( $span->contains( $dt ) ) { ...    # like "is-fully-inside"

           These methods can accept a "DateTime", "DateTime::Set", "DateTime::Span", or
           "DateTime::SpanSet" object as an argument.

SUPPORT

       Support is offered through the "datetime@perl.org" mailing list.

       Please report bugs using rt.cpan.org

AUTHOR

       Flavio Soibelmann Glock <fglock@gmail.com>

       The API was developed together with Dave Rolsky and the DateTime Community.

COPYRIGHT

       Copyright (c) 2003-2006 Flavio Soibelmann Glock. All rights reserved.  This program is
       free software; you can distribute it and/or modify it under the same terms as Perl itself.

       The full text of the license can be found in the LICENSE file included with this module.

SEE ALSO

       Set::Infinite

       For details on the Perl DateTime Suite project please see <http://datetime.perl.org>.