Contributing

Thanks for taking a look. This is a small project; the bar is that a change leaves the codebase easier to read than it found it.

Before you open a pull request

cargo fmt --all
cargo clippy --all-targets -- -D warnings
cargo test

CI runs exactly these, plus the test suite on Linux, macOS and Windows and a build against the minimum supported Rust version. All of it has to pass.

What the code expects of you

• One responsibility per module. Every module starts with a header stating its purpose, its responsibility and its public API. If your change makes that header inaccurate, the change is in the wrong module.
• The editor core stays UI-free. Nothing under src/editor/ may know about terminals, keys or colours. Rendering reads state and never mutates it, with the two documented exceptions in ui::draw.
• Comment the why, not the what. The existing comments explain trade-offs and non-obvious constraints. Comments that restate the code will be asked about in review.
• No unsafe. It is forbidden crate-wide in Cargo.toml.
• Character indices, not bytes. Byte offsets break on UTF-8 and screen columns break on tabs; conversions belong at the edges, in ui::text and the rope accessors.

Commits

Conventional-commit style, scoped to the module you touched:

feat(search): add whole-word matching
fix(ui): keep the caret visible when the gutter width changes

Small commits that each leave the tree building are much easier to review than one large one.

Minimum supported Rust version

Currently 1.88, enforced in CI. Raising it is fine when there is a reason — update rust-version in Cargo.toml and the msrv job in .github/workflows/ci.yml together, and say so in the changelog.

Adding a language to the highlighter

Add a file under src/syntax/languages/, export a &'static Language, and add one line to all(). No engine or rendering change should be necessary; if one is, that is worth discussing in the issue first.