anchor.diff:      with _ ->
         None
   
  -let prims () = 
  +let prims () =
     match get_prims() with
     | None ->
       let filen = "prims.fst" in
  
positive.code: let set_option k v = Util.smap_add (peek()) k v
  let set_option' (k,v) =  set_option k v
  
  let init () = 
    let vals = 
         [
          ("__temp_no_proj"               , List []);
          ("_fstar_home"                  , String "");
  
negative.code:     | "use_eq_at_higher_order"
      | "__temp_no_proj"
      | "warn_top_level_effects" -> true
      | _ -> false
  
  let resettable s = settable s || s="z3timeout"
  let all_specs = specs ()
  let settable_specs = all_specs |> List.filter (fun (_, x, _, _) -> settable x)
  let resettable_specs = all_specs |> List.filter (fun (_, x, _, _) -> resettable x)
  
  
  /////////////////////////////////////////////////////////////////////////////////////////////////////////
  //PUBLIC API
  /////////////////////////////////////////////////////////////////////////////////////////////////////////
  let display_usage () = display_usage_aux (specs())
  
  let fstar_home () =
      match get_fstar_home() with
      | None ->
        let x = Util.get_exec_dir () in
        let x = x ^ "/.." in
        set_option' ("fstar_home", String x);
  