table-sorting-algorithm-TC

1. Let table be the table element being sorted.

2. If table's currently-sorting flag is true, then abort these steps.

3. Set table's currently-sorting flag to true.

4. Fire a simple event named sort that is cancelable at table.

5. If the event fired in the previous step was canceled, then jump to the step
   labeled end below.

6. If table is not now a sorting-enabled table element, then jump to the
   step labeled end below.

7. Let key heading cells be the sorting-enabled th elements of the table
   element table.

8. Sort key heading cells in ascending order of the column key ordinality of
   their sorted attributes, with those having the same column key ordinality
   being sorted in tree order.

9. Let row collection cursor be a pointer to an element, initially pointing at
   the first child of table that is after table's first thead, if any, and that
   is either a tbody or a tr element, assuming there is one. If there is no such
   child, then jump to the step labeled end below.

10. If table has no row group corresponding to a thead element, then set ignore
    first group to true. Otherwise, set it to false.

11. Row loop: Let rows be an empty list of tr elements.

12. Repeat while row collection cursor is not null

    12.1 If row collection cursor points to a tr element

        12.1.1 Collect: Append the element pointed to by row collection cursor
               to rows.

        12.1.2 If there are no tr or tbody children of table that are later
               siblings of the element pointed to by row collection cursor,
               or if the next such child is a tbody element, then jump to the
               step labeled group below.

        12.1.3 Let row collection cursor point to the next tr child of table
               that is a later sibling of the element pointed to by row
               collection cursor.

        12.1.4 Return to the step labeled collect above.

    12.2 If row collection cursor points to a tbody element

        12.2.1 Place all the tr element children of the element pointed to by
               row collection cursor into rows, in tree order.

        12.2.2 If rows is empty, jump to the step labeled increment loop below.

    12.3 Group: Let groups be an empty list of groups of tr elements.

    12.4 Let group be an empty group of tr elements.

    12.5 Let group cursor be a pointer to an element, initially pointing at the
         first tr element in rows.

    12.6 Start group: Let pending rows in group be 1.

    12.7 Repeat while group cursor is not null

        12.7.1  Repeat while group curosr is not null and pending rows in group
                is not zero:

            12.7.1.1 Append the tr element pointed to by group cursor to group.

            12.7.1.2 If there are any cells whose highest row's element is the
                     one pointed to by group cursor, then let tallest height be
                     the number of rows covered by the tallest such cell.

            12.7.1.3 If tallest height is greater than pending rows in group
                     then set pending rows in group to tallest height.

            12.7.1.4 Decrement pending rows in group by one.

            12.7.1.5 Let group cursor point to the next tr element in rows, if
                     any; otherwise, let it be null.

        12.7.2 Append a new group to groups consisting of the tr elements in group.

        12.9 Empty group