# File packstruct.rb, line 58
        def pack
                o = ''
                fields.each_index do |f|
                        if types[f].kind_of? Class
                                t = self.send(fields[f]).pack
                        else
                                t = [self.send(fields[f])].pack(types[f])
                        end
                        $stderr.puts("#{fields[f]}: #{t.inspect}")
                        o << t
                end
                o
        end