type XlsxSheetData = class
public
    function Create(sheet_data: SheetData);
    function Operator[](index: integer): XlsxSheetDataRow;
    function Cell(r: integer; c: integer): C;
    function Rows(index: integer): XlsxSheetDataRow;
    function Serialize();

private
    rows_: array of XlsxSheetDataRow;
    sheet_data_: SheetData;
end;

function XlsxSheetData.Create(sheet_data: SheetData);
begin
    rows_ := array();
    sheet_data_ := sheet_data;
    rows := sheet_data.Rows();
    for i:=0 to length(rows)-1 do
    begin
        r := strToInt(rows[i].R);
        rows_[r] := new XlsxSheetDataRow(rows[i]);
    end
    // println("rows = {}", rows_);
end;

function Operator XlsxSheetData.[](index: integer): XlsxSheetDataRow;
begin
    if ifnil(rows_[index]) and tslassigning then
    begin
        row := new Row(sheet_data_, "", "row");
        rows_[index] := new XlsxSheetDataRow(row);
        pos := -1;
        for k,_ in rows_ do  // TODO：此处弊端是要遍历所有k，可考虑维护一个新array，用二分
            if pos < k and k < index then pos := k;
        pos = -1 ? sheet_data_.AppendChild(row) : sheet_data_.InsertAfter(row, rows_[pos].Data());
    end
    return rows_[index];
end;

function XlsxSheetData.Rows(index: integer): XlsxSheetDataRow;
begin
    return self[index];
end;

function XlsxSheetData.Cell(r: integer; c: integer): C;
begin
    bk := tslassigning;
    tslassigning := 1;
    c := self[r][c];
    tslassigning := bk;
    return c;
end;

function XlsxSheetData.Serialize();
begin
    for k,row in rows_ do
    begin
        r := row.Data();
        r.R := k;
        row.Serialize();
    end
    // sheet_data_.Serialize();
end;