<'
type   kind_default_values  : [good, bad];
type   kind_assigned_values : [good = 2, bad = 3];
type   kind_only_few        : [good = 3, bad];
// Empty 
type   packet_protocol: [];
// Extend
extend packet_protocol : [Ethernet, IEEE, foreign];
//Sized 
type   packet_kind: [good, bad] (bits: 2);

struct data_types3 {
  packet_type  :  packet_protocol;
  packet_valid :  packet_kind;
};
// Just to check our code
extend sys {
  data : data_types3;
  run() is also {
    gen data;
    print data;
    gen data;
    print data;
    gen data;
    print data;
  };
};
'>