anchor.diff:  procedure TNullableDouble.SetValue(AValue: Double);
   begin
     InternalSetValue(AValue);
  -  FTagChanged:= false;
  +  SetTagChanged(false);
   end;
   
   procedure TNullableDouble.InternalSetValue(AValue: Double);
  
positive.code: procedure TNullableInteger.SetValue(AValue: Integer);
  begin
    InternalSetValue(AValue);
    FTagChanged:= false;
  end;
  
  procedure TNullableInteger.InternalSetValue(AValue: Integer);
  begin
    FValue:= aValue;
    FIsNull:= false;
  end;
  
  constructor TNullableInteger.Create();
  
negative.code: 
  function TNullableTime.AsVariant: Variant;
  begin
    if Self.GetIsNull then
      Result := Null
    else
      Result := FValue;
  