use Modern::Perl;

use Benchmark qw[ cmpthese ];

sub deref {
    my $r = shift;
    ++$r->[$_][1] for 0..$#$r;
}

sub alias {
    our @a;
    local *a = shift;
    ++$a[$_][1] for 0 .. $#a
}

sub deref_iter {
    my $r   = shift;
    $_->[1]++ for @$r;
}

sub alias_iter {
    our @a;
    local *a = shift;
    $_->[1]++ for @a;
}

my @a = map[1..3],1..1e6;

cmpthese -1, {
    deref      => sub { deref( \@a ) },
    alias      => sub { alias( \@a ) },
    deref_iter => sub { deref_iter( \@a ) },
    alias_iter => sub { alias_iter( \@a ) },
};