Do not exit in error if the algo is silent

bin/sasa.ml

-(* Time-stamp: <modified the 07/03/2019 (at 15:27) by Erwan> *)
+(* Time-stamp: <modified the 07/03/2019 (at 16:23) by Erwan> *)
 
 (* XXX Je pourrais utiliser Lwt pour rendre step non-bloquant, ce qui
    permettrait d'accelerer la simu sur les machines qui ont plusieurs
@@ -72,7 +72,7 @@ let (to_algo_neighbor: Env.t -> Topology.neighbor -> Algo.neighbor) =
       n_vars = n.Topology.n_vars
     }
 
-exception Silent
+exception Silent of int
   
 let rec (simu: int -> int -> Process.t list ->
          (Process.t * Topology.neighbor list) list -> Env.t -> unit) =
@@ -86,7 +86,7 @@ let rec (simu: int -> int -> Process.t list ->
            if al <> [] then al::acc else acc)
         [] pl_n
     in
-    assert (all <> []);
+    if  (all = []) then raise (Silent i);
     let al = Demon.f args.demon all in
 
     (* Do the steps *)
@@ -106,7 +106,7 @@ let rec (simu: int -> int -> Process.t list ->
     Printf.eprintf "step %s: %s (%s)\n" (string_of_int (n-i)) (StringOf.env e pl) al_str;
     match all with
     (*     | [_] -> () *)
-    | [] -> raise Silent
+    | [] -> raise (Silent i)
     | _ ->  if i > 0 then simu n (i-1) pl pl_n ne else ()
 
 let () =
@@ -139,4 +139,6 @@ let () =
     List.iter dump_process pl_n;
     let n = SasArg.args.length in
     simu n n pl pl_n e
-  with Dynlink.Error e -> Printf.printf "E: %s\n"(Dynlink.error_message e)
+  with
+  | Dynlink.Error e -> Printf.printf "E: %s\n"(Dynlink.error_message e)
+  | Silent i -> Printf.printf "This algo is silent after %i steps\n" i