sub thread
{
my%children;
for my $root (sort {$a <=> $b} keys %created){ # for all nodes
   my(@kids,$kids);
   # if doesn't have a parent and isn't a user
   if( ($nodetype{$root} ne 'user') ){
      for my $child (sort {$a <=> $b} keys %parent){ # for all children
         if( ($parent{$child} == $root) ){ # if this is a child
            push @kids, $child;
            } # if
         $kids = join '|', @kids;
         $children{$root} = $kids;
         }
      }
   } the rest is predictable noise...