The Schwartzian Transform is explained here by the person after who this sorting technique is named.

A modified version of the sorted routine which also takes the leading letters into account:

sub sorted { 
    return map { $_->[0] }
    sort { 
        $a->[1] cmp $b->[1] ||
        $a->[2] <=> $b->[2] ||
        $a->[3] <=> $b->[3]
    } map { [ $_, (/([A-Z]+)(\d+)(?:-(\d+)){1,2}/) ] } @_;
}
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The split function is replaced by a regex which returns a list of letters and the numbers.

Arjen