Memory layout of a data structure

The following is specced to work, but implementation of shaped arrays is not quite complete.

enum T_RS232 <
    carrier_detect
    received_data
    transmitted_data
    data_terminal_ready
    signal_ground
    data_set_ready
    request_to_send
    clear_to_send
    ring_indicator
>;

my bit @signal[T_RS232];

@signal[signal_ground] = 1;

In the absence of shaped arrays, you can do the usual bit-twiddling tricks on a native integer of sufficient size. (Such an integer could presumably be mapped directly to a device register.)

$signal +|= 1 +< signal_ground;

Using a native int is likelier to work on a big-endian machine in any case. Another almost-there solution is the mapping of C representational types into Raku for native interfaces, but it does not yet support bit fields.