STLC++ for Visual Studio Code

TODOs

• Build with Nix and don't include the wasm file as a binary

Tree-sitter based syntax highlighting for the STLC++ language.

Features

• Syntax highlighting for .stlc files using tree-sitter
• Bracket matching and auto-closing
• Comment toggling with Ctrl+/ (or Cmd+/ on macOS)

Installation

From GitHub Release

1. Download the .vsix file from the Releases page
2. Install in VSCode:

   code --install-extension extension.vsix

From Source

git clone <repo-url>
cd vscode-stlcpp
npm install
npm run compile
npx vsce package
code --install-extension stlcpp-*.vsix

Supported Syntax

• Keywords: if, then, else, case, lcase, of, let, in, fun, forall, import, Type
• Fixity declarations: infixl, infixr, prefix
• Constructors: nil, cons, inl, inr
• Projections: fst, snd
• Booleans: true, false
• Builtins: __print, __pure, __bind, __readline
• Debug: panic, trace, fix
• Type identifiers: [A-Z][A-Za-z0-9]*
• Term identifiers: [a-z][A-Za-z0-9._']*
• String and character literals with escape sequences
• Comments: // ...
• Operators: ->, =>, ==, custom operators

Testing

npm ci
npm test

npm test runs the release safeguards, dependency/packaging checks, and editor tests. The editor tests build a VSIX, install it in an isolated VS Code profile, and exercise the packaged extension: automatic .stlc activation, WASM loading, syntax highlighting, Unicode positions, edits, incomplete files, comment toggling, bracket matching and automatic closing. Your normal editor profile is not used.

VS Code is downloaded to .vscode-test/ on the first run. Linux needs a display; on a headless machine use xvfb-run -a npm test.

To test an existing artifact without rebuilding it:

npm run test:extension -- --vsix extension.vsix

The current test version is pinned in package.json under config.vscodeTestVersion. Use --version 1.75.0 to check the declared minimum supported VS Code release. Failed runs retain their temporary profiles at the path printed by the runner and copy available VS Code logs into .vscode-test/run-*/. CI tests the same built VSIX on Linux, macOS and Windows, plus the minimum VS Code release on Linux. All editor checks must pass before a GitHub Release or marketplace upload can start.

Releases

Publishing starts only when a new vMAJOR.MINOR.PATCH tag is pushed. A maintainer or AI creates and pushes the tag; the workflow does not bump versions or create tags. Both plugin repositories use the same release process:

1. Update package.json and package-lock.json together, for example with npm version patch --no-git-tag-version. Add a non-empty entry for that exact version to CHANGELOG.md under ## [MAJOR.MINOR.PATCH].

2. Merge those changes into main and wait for CI to pass.

3. Create and push the matching tag on the tested commit. Replace X.Y.Z below with the new package version:

   git fetch origin main
   git tag -a vX.Y.Z origin/main -m "Release X.Y.Z"
   git push origin vX.Y.Z

The tag workflow validates the new tag, versions, changelog and membership in main, runs tests, and builds one VSIX. It then creates the GitHub Release with that changelog and VSIX attached. After the release succeeds, it uploads that same VSIX to Visual Studio Marketplace and Open VSX using trusted publishing. A validation, test, build or GitHub Release failure prevents marketplace uploads.

Branch pushes, pull requests and manual workflow runs only validate/package; they never publish. Moving an existing tag is rejected. For a failed release, use Re-run failed jobs on the original tag run so it reuses the same artifact; do not move tags or rerun successful marketplace uploads.

The publishing guide records the trusted-publisher setup, release safeguards, dry runs and retry procedure.

Related

• tree-sitter-stlcpp - Tree-sitter grammar for STLC++

Licensing and contributions

This project's software and technical documentation are MIT licensed. Separately licensed third-party material and dependencies retain their existing licenses and notices. The software license does not license separately supplied course content, assignments, solutions, or student submissions.

All contributors, including maintainers and direct committers, must follow CONTRIBUTING.md and have the rights to submit their original contributions under MIT.

Contributors

Thanks to the people who have contributed to this project. This static snapshot preserves commit authors and human coauthors from the default-branch history through bcdaf31, reviewed on 22 October 2026. Aliases have been consolidated; unmerged branch contributions are not included.

• @lajp
• @superseacat
• @xhalo32

Automation credits

Git history also records Dependabot, Claude. These are listed separately from human contributors.

These credits are not a statement of copyright ownership or a license grant. Keep them when moving repositories or replacing history; add future contributors without removing the historical credits.