Contributing to the compiler

This section is for people working on Bynk itself — the bynkc compiler and its sibling tools — rather than people writing Bynk programs. If you are here to use Bynk, start with the tutorials.

The repository

Bynk is a Cargo workspace plus two JavaScript/TypeScript projects:

Crate / project	What it is
`bynkc`	The compiler and CLI (`bynkc`): lex → parse → resolve → check → emit.
`bynk-fmt`	A thin crate re-exporting the formatter from `bynkc::fmt`.
`bynk-lsp`	The language server (`bynkc-lsp`), built on `tower-lsp`.
`tree-sitter-bynk`	The grammar (`grammar.js` → generated parser) and highlight queries.
`vscode-bynk`	The VS Code extension.

The workspace targets the Rust 2024 edition.

Build and test

cargo build                 # build all workspace crates
cargo test                  # run the whole Rust test suite
cargo test -p bynkc         # just the compiler's tests

cargo test -p bynkc runs, among others:

the fixture suite (tests/e2e.rs) — the heart of the compiler’s tests;
the tsc verification gate (tests/tsc_verify.rs);
the generated-reference checks and the doc-example gate for the book.

See Testing & fixtures for how these work and how to update them.

A few conventions

BYNK_BLESS=1 is the project-wide “regenerate expected output” switch. It re-blesses fixture expectations and the generated reference pages. Run it deliberately and review the diff.
The spec is the source of truth; the design notes are rationale. The normative spec under site/src/content/docs/book/spec/ defines the current language and is updated per increment; the decisions behind increments live in design/decisions/. The remaining design/*.md notes are rationale and history — some are aspirational or predate the Rust rewrite. Trust the fixtures and the code for current behaviour.
Docs ship with the feature. Each increment updates the book in the same change — see Working on the docs.

Where to look

Compiler architecture — the pipeline and the crates.
Testing & fixtures — the fixture formats, the bless workflow, the tsc gate.
Working on the docs — the book, its generators, and its guardrails.