use strict;
use warnings;
use Data::Dumper;

# Prototype defined to avoid 'function not defined' warnings
# on compilation.
sub unpack_row{
    my $hash = shift;
    my @row = @_;
    if(ref($hash) eq 'HASH'){
        my $header = $hash->{'header'};
        my @results = ( );
        while(my ($key, $value) = each(%$hash)){
            # Save the results the way you need them...
            push @results, unpack_row($value, (@row, $key));
        }
        return (@results);  # ... or whatever you return
    } else {
        print Dumper((@row, $hash));
        return (@row, $hash);
    }
}

my $hash = {};
$hash->{'foo'}->{'bar'}->{'bat'} = 5;
print unpack_row($hash, ());