/****************************************************************/
 /*          S A S   S A M P L E   L I B R A R Y                 */
 /*                                                              */
 /*    NAME: WORM                                                */
 /*   TITLE: ANIMATED WORM ON DISPLAY                            */
 /* PRODUCT: IML                                                 */
 /*  SYSTEM: ALL                                                 */
 /*    KEYS: MATRIX FS                                           */
 /*   PROCS: IML                                                 */
 /*    DATA:                                                     */
 /*                                                              */
 /* SUPPORT: LWB                         UPDATE:  NOV1989        */
 /*     REF:                                                     */
 /*    MISC:                                                     */
 /****************************************************************/
proc iml; 
 /*---worm---*/
 /* head @ body = food X empty .  barrier / */
start worminit;
  window w rows=14 columns=22 icolumn=20;
  rowmove={0  0 1 -1};
  colmove={1 -1 0  0};
  nr=10; nc=20;
  a = repeat("X",nr,nc);  /* the game field */
  a[3,8:12]="/";
  a[7,8:12]="/";
  r = { 5 5 5 5 };        /* initial row position */
  c = { 8 9 10 11};       /* initial col position */
  loc=(r-1)*nc+c;
  a[loc]={"@" "=" "=" "="}; /* place worm in field */
*  a[3,7:13]="B";
*  a[7,7:13]="B";
  ok = 1;
  finish;
 
start wormmove;
  /*-clear old tail-*/
  a[r[4],c[4]]='.';
  a[r[1],c[1]]="=";
  r=r[{4 1 2 3}];
  c=c[{4 1 2 3}];
 
  /*-try new direction-*/
  iii=0;
tryagain: iii=iii+1; if iii>20 then do; ok=0; stop;  end;
     move=int(uniform(0)#4)+1;
     r1 = r[2]+rowmove[move];
     c1 = c[2]+colmove[move];
     if r1<1
      | r1>nr then goto tryagain;
     if c1<1
      | c1>nc then goto tryagain;
     if a[r1,c1]^="X" then
     if a[r1,c1]^='.' then goto tryagain;
   freq=256; if a[r1,c1]="X" then freq=312;
   /*--make new move--*/
   r[1] = r1;
   c[1] = c1;
   a[r1,c1]="@";
finish;
freq=256;
 
start wormshow;
 showa = cshape(a,nr,1,nc);
 display w ( / showa color="YELLOW" protect=yes ) repeat;
 call sound(freq,.05);
finish;
 
run worminit;

start;
 do i=1 to 100; run wormshow; run wormmove; end;
finish;
 
 /* You can ask the worm to "run" as many times as you like. */
 /* The run; below will get him started.                     */
run;