There's a few ways you could do it. I'd do it as such:

sub someMethod {
    my $self = shift;

    my $hashRef;
    if (UNIVERSAL::isa($_[0], 'HASH')) {
        $hashRef = shift;
    } else {
        $hashRef = { @_ };
    }
}
[download]

Of course, you can add more checks and lots of cool stuff. But, that's basically the idea.

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We are the carpenters and bricklayers of the Information Age.

Don't go borrowing trouble. For programmers, this means Worry only about what you need to implement.