Re^2: Are there corner cases I am missing

[GrandFather]

If you are saying you are passing a huge list (more than 3) of position dependent parameters to a sub then you are buying yourself trouble right from the get go. Instead load up a hash with the parameters as you discover them then pass the hash into the sub. That gives you the equivalent of named parameters. Consider:

use 5.010;
 ...

my %params;
my @parts = split '.', $mystring;
$params{cheese} = $parts[0];
$params{country} = $parts[1];
$params{state} = $parts[2];
$params{town} = $parts[3];

doSumpton(%params);

 ...

sub doSumpton {
    my %params = @_;

    $params{cheese} //= '-- bad cheese --'; # Provide cheesy default
    print "Cheese: $params{cheese}\n";
}

Using a hash slice the assignments to the hash can be done as:

@params{qw(cheese country state town)} = @parts;