use Data::Dumper;
use strict;
use warnings;

my $hashref;
my @foo = qw[1 2 3 4 5];

my $string = "\$hashref->";

foreach	my $item (@foo)
{
	$string .=	"{$item}";
}
$string	.= "= undef";

eval($string);
print Dumper($hashref);