Proposes the computation half of the math work (schemas in ExaDev/document-schema.js#15, lowering in #572): a sibling package — compute.js, say — exposing pure functions over serialisable data, per the platform's contracts doctrine:
evaluate(expression, bindings, context) -> Quantity | interval | error as a tree-walking interpreter over MathExpression, with optional compile-to-JS for hot paths. FormulaBindings and Quantity schemas land in document-schema.js beside the math value itself so evaluation inputs are typed contracts like everything else.- Units as the type system: inputs carry units, results derive units, and adding quantities of incompatible dimensions is a hard error rather than a silent wrong number. Exact rationals for unit-conversion chains.
- Interval arithmetic over the same evaluator for the bounded-values case: compliance regions over min/max bounds (
0.87 <= cos φ <= 1) almost for free once points work.
- Numeric solve-for via root-finding over our own evaluator (bisection/Newton on one unknown) — covers most rearrangement needs with no symbolic engine.
- Symbolic work (exact rearrangement emitted as LaTeX, simplification, integration) behind an evaluator interface with a SymPy sidecar as the first adapter; in-house selective algebra (linear-in-target rearrangement) can migrate in later if usage justifies it.
Scope line: this is deliberately not a CAS in the Mathematica sense — units-typed evaluation and numeric solving are the 90% of "compute the result of a formula from a document" and are buildable natively now.
The test harness is the differentiator: worked examples — documents that state a formula and then compute it with numbers — give input-to-expected-output pairs for free. Coverage becomes a measured number: the fraction of parsed formulae whose evaluation reproduces the document's own stated answer, with every miss pointing at a specific gap (missing symbol binding, units convention, unsupported construct).
Proposes the computation half of the math work (schemas in ExaDev/document-schema.js#15, lowering in #572): a sibling package —
compute.js, say — exposing pure functions over serialisable data, per the platform's contracts doctrine:evaluate(expression, bindings, context) -> Quantity | interval | erroras a tree-walking interpreter overMathExpression, with optional compile-to-JS for hot paths.FormulaBindingsandQuantityschemas land in document-schema.js beside the math value itself so evaluation inputs are typed contracts like everything else.0.87 <= cos φ <= 1) almost for free once points work.Scope line: this is deliberately not a CAS in the Mathematica sense — units-typed evaluation and numeric solving are the 90% of "compute the result of a formula from a document" and are buildable natively now.
The test harness is the differentiator: worked examples — documents that state a formula and then compute it with numbers — give input-to-expected-output pairs for free. Coverage becomes a measured number: the fraction of parsed formulae whose evaluation reproduces the document's own stated answer, with every miss pointing at a specific gap (missing symbol binding, units convention, unsupported construct).