The "recurrence" function should return the "next" recurrence. This is one way to implement it:
#!/usr/bin/perl
use strict;
use warnings;
use DateTime;
use DateTime::Format::Strptime;
use Datetime::Set;
# use Data::Dumper;
my $strp = DateTime::Format::Strptime->new(
pattern => '%Y-%m-%d %T',
);
my $datf = qq{2012-01-01 04:00:00};
my $datt = qq{2012-01-02 23:00:00};
my $start = $strp->parse_datetime($datf);
my $end = $strp->parse_datetime($datt);
my $iter;
my $set = DateTime::Set->from_recurrence(
after => $start,
before => $end,
recurrence => sub {
return $_[0]->add( hours => 1 )->truncate( to => 'hour' )
},
);
print "first set:\n";
$iter = $set->iterator;
while ( my $dt = $iter->next )
{
print $dt->datetime, "\n";
};
my $set2 = $set->grep(
sub {
return ( $_->hour > 7 && $_->hour < 23);
}
);
print "second set:\n";
$iter = $set2->iterator;
while ( my $dt = $iter->next )
{
print $dt->datetime, "\n";
};