microtables/CONTEXT.md

Microtables Frontend

The spreadsheet grid: cell data, formula evaluation, and keyboard/selection interaction for a lightweight spreadsheet app.

Language

Totals Row: A display-only summary rendered below the grid, viewport-pinned (sticking just above the control bar) so it stays visible while scrolling. Shows one aggregate per column, computed from that column's numeric cells; non-numeric and blank cells are skipped. Clicking the row's header cell cycles its display mode between sum, average, and both (stacked, smaller font); the header symbol itself changes to reflect the active mode. It is not stored in :table-data and has no row number — it cannot be selected, edited, or referenced by a formula. Styled distinctly from both the header row and data rows so it isn't mistaken for either. Avoid: treating it as "row 21" or as a stored/data row

Numeric Cell (for Totals Row purposes): A cell whose display value is a number, whether typed directly or produced by a formula. If any cell in a column is in an error state, that column's total shows an error indicator instead of a sum — an errored cell is never silently skipped.