As an aside, am I committing the sin of premature optimization if I worry that passing as a hash is less efficient than passing as a hashref? I mean, doesn't this:

my %params =
(
    param1 => 'thing',
    param2 => 'other thing',
    # bunches o' stuff
    param61 => 'whew!',
);

initialize_object(%params);

# later ...

sub initialize_object
{
    my %params = @_;

    # do something useful, presumably
}
[download]

actually copy all 61 parameters not once but twice? As opposed to:

my $params =
{
    param1 => 'thing',
    param2 => 'other thing',
    # bunches o' stuff
    param61 => 'whew!',
};

initialize_object($params);

# later ...

sub initialize_object
{
    my ($params) = @_;

    # do something useful, presumably
}
[download]

? I noticed some people preferred hashref's to hashes, but no one mentioned this as a reason ... is the overhead too little to fret about really?

Just curious.