anchor.diff:    result.RollUp;
   end;
   
  +class operator TDateTimeEx.LessThan(a, b: TDateTimeEx): Boolean;
  +begin
  +  result := a.before(b, false);
  +end;
  +
  +class operator TDateTimeEx.LessThanOrEqual(a, b: TDateTimeEx): Boolean;
  +begin
  +  result := a.before(b, true);
  +end;
  +
   function TDateTimeEx.link: TDateTimeEx;
   begin
     result := self;
  
positive.code: 
      function clone : TDateTimeEx;
      function link : TDateTimeEx;
    end;
  
  {$IFDEF MSWINDOWS}
  
negative.code:   result.FPrecision := dtpNanoSeconds;
  end;
  
  class operator TDateTimeEx.NotEqual(a, b: TDateTimeEx): Boolean;
  begin
    result := not a.equal(b);
  end;
  
  function TDateTimeEx.notNull: boolean;
  begin
    result := Source <> '';
  