use strict;
use warnings;

showParams(fat => => 'comma');
showParams('real', , 'comma');
showParams('explicit', undef, 'comma');

sub showParams {
    my @params = @_;

    for my $param (@params) {
        if (!defined $param) {
            print ">undef<\n";
            next;
        }

        if (ref $param) {
            print "'", ref $param, "'\n";
            next;
        }

        print "'$param'\n";
    }

    printf "\n";
}