Cell.formula is not always equal to Cell.value. The UI should be able to display both of them: Cell.formula in the formula bar and Cell.value in the cell
Cell formula should always be used when sending values from the UI to the core (Sheet::setCell). The cell's value is resolved within the core and should only be used for rendering the cell.
The UI can access the cell value from the return value of Sheet::setCell (and any other relevant methods).
Cell.formulais not always equal toCell.value. The UI should be able to display both of them:Cell.formulain the formula bar andCell.valuein the cellSheet::setCell). The cell's value is resolved within the core and should only be used for rendering the cell.Sheet::setCell(and any other relevant methods).