anchor.diff:      procedure Clear;
       function Contains(const Value: Variant): Boolean;
       function Delete(Index: Integer): Variant;
  +    procedure DeleteRange(Index, Count: Integer);
       procedure Exchange(Index1, Index2: Integer);
       function GetEnumerator: IListEnumerator;
       function IndexOf(const Value: Variant): Integer;
  
positive.code:     procedure Grow; overload; virtual;
      procedure Grow(N: Integer); overload; virtual;
      procedure Shift(Index, N: Integer); virtual;
      procedure Put(Index: Integer; const Value: Variant); override;
      function GetCapacity: Integer; override;
      function GetCount: Integer; override;
  
negative.code:     procedure Clear; virtual; abstract;
      function Contains(const Value: Variant): Boolean; virtual; abstract;
      function Delete(Index: Integer): Variant; virtual; abstract;
      procedure DeleteRange(Index, Count: Integer); virtual; abstract;
      procedure Exchange(Index1, Index2: Integer); virtual; abstract;
      function GetEnumerator: IListEnumerator; virtual;
      function IndexOf(const Value: Variant): Integer; virtual; abstract;
  