anchor.diff:  var
     Tag: Byte;
   begin
  +  Tag := 0;
     FStream.ReadBuffer(Tag, 1);
     case Tag of
       htNull,
  
positive.code: var
    Tag: Byte;
  begin
    FStream.ReadBuffer(Tag, 1);
    case Tag of
      htNull,
  
negative.code: var
    Tag: Byte;
  begin
    Tag := 0;
    FStream.ReadBuffer(Tag, 1);
    case Tag of
      Byte('0')..Byte('9'): Result := string(Char(Tag));
  