(* à ajouter à la fin du cours 6 *)
type instruction = Printstr of string
                 | Print of expression
                 | Block of instruction list
                 | Affectation of int * expression
                 | While of expression * instruction;;

let rec exec = function
  | Printstr s -> print_string s
  | Print e -> print_int (eval e)
  | Block [] -> ()
  | Block (x::xs) -> exec x;
                     exec (Block xs)
  | Affectation (n, e) when n < 4 && n >= 0 -> etats.(n) <- (eval e)
  | Affectation (n, e) -> raise Segfault
  | While (e, i) as w -> (match (eval e) with
                          | 0 -> ()
                          | _ -> exec i; exec w);;


"x = 10;
 while (x < 40) {
 print x;
 println;
 x = x + 10;
 }";;
let p = Block [
            Affectation (0, Ent 10);
            While ( Inf (Var 0, Ent 40),
                    Block [
                        Print (Var 0);
                        Printstr "\n";
                        Affectation (0, Plus ((Var 0), Ent 10))
                  ])
          ];;

exec p;;