face::CellData

Data structure for spreadsheet cell content.

Detailed description

CellData stores cell expression and computed value. As of Phase 9 of expression-system-consolidation, CellData::update() handles the **literal/empty** path only — formula evaluation is delegated to face::SpreadsheetEngine, which owns cross-cell dependency tracking through eval::Graph + Program.

SpreadSheetModel calls update() for the literal fast path, then asks the engine for the current value via SpreadsheetEngine::cellValue for formula cells.

See also face::SpreadSheetModel, face::SpreadsheetEngine.