Module csv_cell 

The single CSV cell escaper for this crate — RFC 4180 quoting plus the CWE-1236 formula-injection guard, pinned to the TypeScript half by tests/csv_cell_parity.rs. THE CSV cell escaper for this repository’s Rust.

Every Rust producer of CSV calls [escape_csv_cell] and nothing else. The TypeScript half lives in packages/export/src/csv-cell.ts; both are pinned to the shared vectors in tests/fixtures/csv_cell_vectors.json by tests/csv_cell_parity.rs and csv-cell.parity.test.ts, so the two languages cannot drift apart silently.

Two things it does that the previous hand-rolled copies did not:

• The formula-injection guard (CWE-1236) looks past leading invisibles. Testing the trigger anchored at offset 0 — as this crate did — means a BOM, ZWSP, LRM, NBSP or U+2028 in front of = walks straight through, because none of those stops a spreadsheet evaluating the cell.
• It looks past them without DELETING them, so a benign " Wall A" keeps its spaces (RFC 4180 §2.4: “Spaces are considered part of a field and should not be ignored”).

Structs

CsvCellOptions

Options for escape_csv_cell.

Functions

escape_csv_cell

Escape one CSV cell: neutralise spreadsheet formula injection (CWE-1236), then apply RFC 4180 quoting.

is_invisible_prefix

Is c an invisible that can hide a formula trigger behind it?

is_padding

Whitespace for the opt-in CsvCellOptions::quote_whitespace_padded rule.