anchor.diff:        function Lookup  : boolean;
         function IsNumber : boolean;
         procedure NotFound;
  +      procedure Error( s : TStr);
   
         function GetModule( iden : TStr ) : TImpModule;
         procedure Mount( iden : TStr; imod : TImpModule ); overload;
  
positive.code:   end;
  
  procedure TImpForth.NotFound;
    begin
      msg := tok + '?';
    end;
  
  
negative.code:   TThunk    = procedure of object;
    TImpStack = GStack<variant>;
    TCmdQueue = TQueue<integer>;
    EImpError = class (Exception) end;
    TWord	 = record
      // prev : address;
      word : TStr;
  