Yes, that's why I suggested the second approach using references. But I neglected to point out the dangers to the original poster. Thanks!

FWIW, I do like to use it if (and only if...) the function is designed to receive only named parameters. E. g.

sub create {
    my $self = shift;
    my %p = @_;
    
    print "$p{color} p{animal}" for (1..$p{count});
}

$zoo->create(animal => 'camel',
             count  => '10',
             color  => 'green');
[download]

One could opt to create the zoo using a hash reference as in

$zoo->create({animal => 'monkey', ...});

but I guess that is a matter of style.