system_object process
  dir_list "/proc/[1-9]*"

  constructor <<
    $pid = atoi ($basename);
  >>

  property int pid (* implicit *)

  property string short_command
  <<
    // some code to parse $filename/stat
  >>
  property char state
  <<
    // some code to parse $filename/stat
  >>

  writable property foo << ... >>

  method err kill (signal sig)
  <<
    return kill ($pid, sig);
  >>
  method bool exists ()
  <<
    int r = kill ($pid, 0);
    if (r == 0)
      return 1;
    if (r == -1 && errno == ESRCH)
      return 0;
    save_errno ();
    return -1;
  >>