There's quiet music on this site. It stays off unless you choose it, and it keeps playing as you move between pages.
The same idea, rebuilt for scale. Sparse storage means empty cells cost nothing, cell indices are usize so there is no fixed size, and the engine runs right here as WebAssembly.
The C version stores every cell up front. Here the grid is sparse: cells live in blocks that exist only once something is written. A sheet with ten values uses memory for ten values.
Indices are usize, so the sheet is not capped at 1.8 crore cells. ZZZZ999999 works.
With sparse storage and a faster dependency engine, a full recalculation on very large sheets dropped from 2–3 minutes to a few seconds.
Every edit is recorded on an operation stack with its old and new state, so undo and redo are exact. Values are floating point, with clean errors for bad formulas.
The engine is a Cargo workspace library with no idea a terminal exists. The CLI, this browser build and the AWS S3 static site all call the same code.
Team project: we designed the engine together.
