anchor.diff:      function AsFloat : Double;
   
       property Value : Double read GetValue write SetValue;
  +    property Digits : byte read FDigits write SetDigits;
     end;
   
     { TNullableBoolean }
  
positive.code:     Result := Null;
  end;
  
  { TNullableBoolean }
  
  function TNullableBoolean.GetValue: Boolean;
  
negative.code: 
  function TNullableInteger.AsString: String;
  begin
    Result := TNullableInteger.VariantToString(Self.AsVariant);
  end;
  
  class function TNullableInteger.StringToVariant(const aValue: String): Variant;
  