bilig

Formula Language

Current state

• JS is still the semantic oracle
• canonical production routing is closed for 300 of 300 canonical rows
• 0 canonical rows remain implemented-js
• 0 canonical rows remain blocked
• the generated source of truth is packages/formula/src/__tests__/fixtures/formula-dominance-snapshot.json

Canonical corpus milestone

The active milestone is the canonical Excel for the web worksheet formula corpus represented in packages/formula/src/compatibility.ts.

The current code-backed canonical registry contains 300 rows.

There are no non-production canonical rows.

The canonical grouped-array SUM forms for GROUPBY and PIVOTBY now route through internal native grouped-array builtins on the wasm path.

Full target

The full formula target remains Excel 365 worksheet parity as of 2026-03-15, including:

• absolute and mixed refs
• quoted sheet refs
• unions and intersections
• %, @, #
• array literals
• defined names
• tables and structured references
• dynamic arrays
• LET
• LAMBDA

Host and service function boundary

The worksheet engine keeps non-worksheet Excel surfaces behind the adapter contract in packages/formula/src/external-function-adapter.ts.

• native builtins stay focused on the worksheet corpus tracked in this package
• cube, web, host-backed, external-data, and add-in-like surfaces register through installExternalFunctionAdapter()
• adapters can expose scalar or range-aware functions to the JS evaluator
• adapted functions do not receive a BuiltinId and do not enter the WASM fast path
• without an installed adapter, those function names continue to resolve as #NAME?

Semantic rules

• Excel for the web is the behavior oracle
• visible error strings follow Excel codes
• JS and WASM must not diverge on coercion, blanks, error precedence, spill blocking, or lookup comparison rules
• a canonical row is not complete until production execution can route it through WASM

Canonical companions

• formula-canonical-program.md
• formula-canonical-matrix.md
• formula-oracle-capture.md
• wasm-runtime-contract.md
• dynamic-array-runtime.md
• workbook-metadata-model.md
• packages/formula/src/__tests__/fixtures/formula-dominance-snapshot.json

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