DEVELOP.md

Developing Styx

Running Tests

# Run all tests
cargo nextest run

# Run tests for a specific crate
cargo nextest run -p styx-format

Property Testing

The formatter uses proptest to find edge cases through fuzz testing. Property tests are in crates/styx-format/src/cst_format.rs.

Two invariants are tested:

1. Semantics preservation - formatting must not change the document's meaning (tree equality ignoring spans)
2. Idempotence - format(format(x)) == format(x)

Run with more cases to find rare bugs:

PROPTEST_CASES=5000 cargo nextest run -p styx-format proptests

When proptest finds a failing case, it saves it to proptest-regressions/ for deterministic replay.

Installing the CLI

cargo xtask install

This builds a release binary, copies it to ~/.cargo/bin/styx, and codesigns it on macOS.

Publishing npm Packages

The Styx playgrounds and editor integrations are published to npm. These packages are loaded via esm.sh CDN in the docs site.

Prerequisites

# For WASM builds
rustup target add wasm32-unknown-unknown
cargo install wasm-bindgen-cli

# npm login (if not already logged in)
npm login

Packages

Package	Location	Description
@bearcove/styx-wasm	crates/styx-wasm	WASM bindings for parser
@bearcove/codemirror-lang-styx	editors/codemirror-styx	CodeMirror 6 language support
@bearcove/monaco-lang-styx	editors/monaco-styx	Monaco editor language support

Publishing

Each package has prepublishOnly scripts that build automatically:

# Publish all packages
cd crates/styx-wasm && pnpm publish
cd editors/codemirror-styx && pnpm publish
cd editors/monaco-styx && pnpm publish

After publishing, the docs site playgrounds will automatically use the new versions via esm.sh (may take a few minutes for CDN cache).

Version Bumps

Update the version in each package.json before publishing. The playground templates in docs/templates/ reference specific versions in esm.sh URLs - update those too:

// docs/templates/monaco.html, codemirror.html
import { ... } from 'https://esm.sh/@bearcove/styx-wasm@0.1.0';