#!/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";
};