Update: handle the Data.Str that was added to lutils in 8619aa285ca8322ab9

lib/lutin/value.ml

@@ -51,7 +51,7 @@ let (from_data_val : Data.v -> t) =
     | Data.I i -> N(I (Num.num_of_int i))
     | Data.F f -> N(F f) 
     | Data.U -> failwith "undefined variable"
-    | (Data.E (_, _)|Data.A _|Data.S _) -> assert false	
+    | (Data.E (_, _)|Data.A _|Data.S _|Data.Str _) -> assert false	
 (* exported *)
 let (num_value_to_string : num -> string) =
   fun n ->