The information of a spreadsheet is organized in cells. Each cell contains a text representing a numerical value, a formula, or (possibly empty) plain text. The value of the cell may affect the values in other cells. If the cell contains a formula, its value may depend on the values in other cells. This implies that each cell has a set of cells whose values it depends on, a source set, and a set of cells. The set's values depend on the cell's value and are called its target set.

There are three classes in this section: Cell, which handles a single cell, CellMatrix, which handles the whole spreadsheet, and TSetMatrix, which handles the target set for all cells. You may wonder why there is a matrix for the target sets, but not for the source sets. The answer is that the cell itself decides its source set. Only formulas have a source set, texts...