G'day eyncydious,

Welcome to the monastery.

Short of manually scripting out:

$chart->plot2d($val1) if $val == 1;
$chart->plot2d($val1,$val2) if $val == 2;
$chart->plot2d($val1,$val2,$val3) if $val == 3;
etc...
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To achieve this, I'd write something like:

my @datasets;
for my $i (...) {
    ....
    push @datasets, Chart::Gnuplot::DataSet->new(...);
    $chart->plot2d(@datasets);
}
[download]