PhysicalConstants are not exposed as PhysicalConstants.Generic<T>() per CLAUDE.md

[matt-edmondson]

Summary

CLAUDE.md documents the public API as:

PhysicalConstants.Generic.SpeedOfLight<T>()
PhysicalConstants.Generic.PlanckConstant<T>()
PhysicalConstants.Conversion.FeetToMeters<T>()

The generated PhysicalConstants class does not expose any Generic or Conversion sub-class with type-parameterised accessors. It only emits non-generic PreciseNumber static readonly fields nested in domain-specific subclasses (AngularMechanics, Chemistry, …).

Evidence

Semantics.Quantities/Generated/.../PhysicalConstants.g.cs:16-50:

public static class PhysicalConstants {
    public static class AngularMechanics {
        public static readonly PreciseNumber DegreesPerRadian = PreciseNumber.Parse("...");
    }
    public static class Chemistry { ... }
    ...
}

No Generic or Conversion partition; no <T> accessors.

Impact

• Public API surface mismatches CLAUDE.md and existing examples.
• Generic physics quantity code that calls PhysicalConstants.Generic.PlanckConstant<T>() will not compile.
• The PhysicalConstantsGenerator is partially wired up.

Suggested next step

Either:

1. Extend PhysicalConstantsGenerator to also emit PhysicalConstants.Generic.{Constant}<T>() and PhysicalConstants.Conversion.{Factor}<T>() accessors that wrap the PreciseNumber values via T.CreateChecked(...), or
2. Update CLAUDE.md and any docs/code samples to match the simpler nested-subclass shape.

Add coverage in Semantics.Test to lock in the chosen API.

Area / Severity

SourceGenerators / Quantities · incomplete

[matt-edmondson]

Resolved. PhysicalConstantsGenerator emits a PhysicalConstants.Generic nested class with T.CreateChecked-backed accessors for every constant — see Semantics.Quantities/Generated/Semantics.SourceGenerators/Semantics.SourceGenerators.PhysicalConstantsGenerator/PhysicalConstants.g.cs (lines 117–168), e.g. PhysicalConstants.Generic.SpeedOfLight<T>(), PhysicalConstants.Generic.PlanckConstant<T>(), PhysicalConstants.Generic.DegreesPerRadian<T>(). The PhysicalConstants.Conversion.*<T>() shape mentioned in the original CLAUDE.md was aspirational and has been removed from the doc in #70 to match what's actually emitted; conversions live in conversions.json / ConversionsGenerator and are consumed via the unit metadata, not as a Conversion sub-class on PhysicalConstants.

---

Generated by Claude Code