use warnings;
use strict;

my $primaryFeatures = {
    'foo', ['fool', 'food', 'foot'],
    'bar', ['barricade'],
};

while (my ($key, $value) = each(%$primaryFeatures)){
   print "($key, $_)\n" for @{ $value };
}

__END__

(bar, barricade)
(foo, fool)
(foo, food)
(foo, foot)

##</code><code>##

my $primaryFeatures = {
    foo => ['fool', 'food', 'foot'],
    bar => ['barricade'],
};