I'm reading through the 3rd part of the beginner's tutorial (http://news.oreilly.com/2008/06/a-beginners-introduction-to-pe.html) and I have a "what if" question. Towards the bottom, there is a piece of code you can look at that parses and summarizes an http log file. One of the functions in it is: 
sub report_section {
    my ( $header, %types ) = @_;

    say $header;

    for my $type ( sort keys %types ) {
        say "$type: $types{$type}";
    }
}

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I'm confused about data types here. Isn't the @_ variable an array? If so, then is the %types hash converted to a flat list or string when passed?

Now, what if I wanted to reference the @_ variable directly, instead of reassigning its parts to variables as is done here. Obviously to print the header, I just write say $_[0];, but how do I handle a passed hash?

I think the answer here is to use references, but I haven't learned much about them yet and I'm wondering if there's a way to do this without them.

EDIT: Some more testing shows me that @_ is a flattened list. @_1 .. $#_ should give me an array that is the %types hash. I tried to substitute sort keys @_[1 .. $#_] instead of sort keys %types, but since I'm only running Perl version 5.8, the keys function does not work. How wrong am I?

In reply to Passing a scalar and hash as subroutine arguments by jktstance

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