Chatting with a nice guy and agreed to a quick code review. I stumbled across the following, presented without comment (note: the author tells me that the code works and has no known bugs).
@data =
map { $_->[1] }
sort { $a->[1] cmp $b->[1] }
map { [substr($_,3,2),$_] }
@in_data;
foreach my $line ( @data ) {
my $key = substr $_,3,2;
# more code here
Looks like the substr($_,3,2)
in the Schwartzian transform isn't used at all. Not a bug, but a no-op.