anchor.diff:      function AsFloat: double;
     end;
   
  -
  -
   implementation
   
   uses
  
positive.code:     function CheckIfDifferentAndAssign(const aValue : Variant) : boolean; override;
      function AsVariant: Variant; override;
      function AsString: String; override;
      function AsFormattedString (aFormat: String): String;
  
      procedure Add (const aValue : integer); overload;
  
negative.code: function TNullableInteger.AsString: String;
  begin
    Result := TNullableInteger.VariantToString(Self.AsVariant);
  end;
  
  function TNullableInteger.AsInteger: integer;
  begin
    if Self.IsNull then
      Result := 0
    else
      Result := FValue;
  end;
  
  function TNullableInteger.AsFormattedString(aFormat: String): String;
  