The results are returned by the bits function as a list. You can iterate over the list using a foreach loop, a hash slice, map, etc.

my %hash;
for my $bits ( bits(3) ) {
    $hash{$bits} = ...;
}
[download]

my %hash;
@hash{ bits(3) } = ...;
[download]

my %hash = map { $_ => ... } bits(3);
[download]