print: File conversion

        sub conversion_path {
          # Do BFS on configuration information
          my ($s, $d) = @_;
          return ($s) if $s eq $d;
          my @queue = ($s);
          my %conversions;
          for (keys %CONF) { push @{$conversions{$1}}, $2 
                if /(.*)->(.*)/; }
          my %good_path_to = ($s => []);
          while (@queue) {
            my ($here) = shift @queue;
            for my $next_type (@{$conversions{$here}}) {
              next if exists $good_path_to{$next_type};  # we've been
            here already
              my $p = [@{$good_path_to{$here}}, $here];
              return @$p, $next_type if $next_type eq $d;
              $good_path_to{$next_type} = $p;
              push @queue, $next_type;
            }
          }
          # no path found
          return;
        }

• @queue is a list of places that the function knows how to get to

• $good_path_to{foo} says how to get from $s to foo

• At each step, it investigates the places reachable from the place at the head of the queue

• If it arrives at the intended destination, it returns

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Copyright © 2005 M. J. Dominus