reference.while

(* reference.while
   
   Reference for highlighting
   Bernhard Reus 15.2.2020
*)

reference read X {
                    //comment
  X:= <pred> X;
  Y:= tl 23;
  Z:= [@while,[@var,0],[]];
  Z:= (X=Y);
  if Z {
         A := [12,X,Y]
  }
  else { Z := nil
  };
 Z:= hd Z;
 Z:= cons 3 cons true Z;
 Z:= cons hd hd hd X cons Y nil;

  switch hd Z {
      case @doHd:   A:= true
      case @doTl:   A:= false
      case @doCons:  A := cons (cons A nil) (tl tl A)
      case @doAsgn:  X := hd tl A
      case @dowhile: if (hd Z) = A
                           {  Z := 0
                              B:= hd tl tl A;
                              B := <reverse> cons Z B; // reverse comment
                              while B
                                 {
                                 }
                           } else
                           {  A := 3545875847
                           }

      case @doIf: A := [1,2,3]
      case @:= : Z:= [true,true,<nil.nil>,@doHd]
      default : Z:= [cons nil 3,true,false,42]
     }; // end switch
  A := [<nil.nil>, <nil.<nil.nil>>,nil]
}
write Z