inbounds/int-function(low, high, val) {
  > val low, < val high.
},

:downlink_fmt/enum {
    (17 |_, :EXTENDED_SQUITTER);
    (18 |_, :NON_TRANSPONDER).
},

:type_code/enum {
   (inbounds 1 4   |_, :AIRCRAFT_IDEN);
   (inbounds 5 8   |_, :SURFACE_POS);
   (inbounds 9 18  |_, :AIR_POS);
   (inbounds 20 22 |_, ---);
   (19 |_, ---);
   (28 |_, ---);
   (29 |_, ---);
   (31 |_, ---).
},

:aircraft_iden/struct { -. tova_tuk_e_sintaktichna_greshka. },

:message/struct {
    DF/enum(:downlinkfmt)    |5,
    CA/enum(:capabilities)   |3,
    ICAO/int-big             |24,
    TC/enum(:type_code)      |5,

    ((TC :type_code:AIRCRAFT_IDEN, aircraft_iden/struct(:aircraft_iden));
     (TC :type_code:SURFACE_POS,   surface_pos/struct {
          POS |1,
          -   |_.
      });
     (TC :type_code:AIR_POS, air_pos/struct(:air_pos))
    ) |51,

    CRC |24.
}.