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Contributing

Contributions are welcome. go-ruby-cmath/cmath is built to a small set of non-negotiable rules — they are what keep it pure-Go, correct, and MRI-compatible. Please read these before opening a pull request.

Hard rules

  • Build from source — no vendoring. Everything compiles from source. Being able to compile from source is a guarantee of independence.
  • 100% test coverage target, enforced in CI. New code ships with tests, and coverage is a CI gate. Fill the error branches, not just the happy path.
  • All GitHub content in English. Issues, pull requests, commits, comments, and discussions are English-only.
  • Differential testing against MRI. Correctness is defined by reference Ruby. A corpus is run through both ruby -rcmath and this library and the results — both the real-vs-complex shape and the float components — are compared, not approximated from memory.
  • Same expressions as the gem. Outside the real branch, use the same closed-form expression CMath's Ruby source uses, so the principal branch cuts stay faithful.
  • Pure Go, cgo disabled. The whole point is a single static binary with no C toolchain. Code must build with CGO_ENABLED=0. If a feature seems to need C, it needs a pure-Go path instead.
  • A reusable library, not the interpreter. This module implements the deterministic mathematics. Anything that needs a live Ruby binding belongs in the consumer, not here.

Workflow

  1. Pick or open an issue describing the change.
  2. Work test-first: add the differential / unit tests, then make them pass.

  3. Run the full suite with coverage and confirm the gate is green:

    go test ./...                       # deterministic + (if ruby present) oracle
COVERPKG=$(go list ./... | paste -sd, -)
go test -coverpkg="$COVERPKG" -coverprofile=cover.out ./...
go tool cover -func=cover.out | tail -1   # total: 100.0%

  4. Open a PR in English, referencing the issue.

Where things live

The library is in github.com/go-ruby-cmath/cmath. This documentation site is in github.com/go-ruby-cmath/docs. Start from the Usage & API page and the Roadmap to find the right place for your change.