Editor support for Hylang (also called Hydrogen). The extension recognizes .hy source files and .hyproj project manifests.
Features
- Syntax highlighting, comments, bracket matching, and indentation for
.hy and .hyproj files.
- Snippets for namespaces, classes,
Main, loops, and console output.
- Immediate structural diagnostics for unmatched brackets, unterminated strings, and block comments.
- Compiler diagnostics from
hy check when the hy executable is available. The extension checks the saved file, or a configured .hyproj target, and shows issues in VS Code's Problems view.
- Document formatting through
hy fmt when using a CLI build that provides it. The released Hydrogen compiler does not currently provide hy fmt.
The compiler is not bundled in the extension. Highlighting, snippets, and structural diagnostics work without it. The extension does not currently provide completion, go to definition, or a language server client.
Build and export a VSIX
Install Node.js and npm, then run these commands from this folder (Hylang-VSCode):
npm ci
npm test
npm run package
npm run package creates dist/hydrogen-language-tools.vsix. This VSIX is the exported plugin file to share or install; it does not publish the extension to the Marketplace. The package script uses the local @vscode/vsce dependency, so a global vsce installation is unnecessary.
Change the extension icon
The extension listing uses assets/hylang-icon.png, specified by the icon property in package.json. To use your own artwork, replace that PNG with a square image of at least 128 × 128 pixels (256 × 256 is recommended), then run npm run package again. Install the rebuilt VSIX with code --install-extension dist/hydrogen-language-tools.vsix --force. The SVG in assets/hydrogen.icon.svg is the editable source for the included icon; VS Code's extension icon must be a PNG.
To try the extension without creating a VSIX, open this folder in VS Code and press F5 to launch an Extension Development Host, or run:
code --extensionDevelopmentPath="$PWD" /path/to/your/hydrogen/project
Install the exported plugin
In VS Code, open Extensions, select the ... menu, choose Install from VSIX..., and select dist/hydrogen-language-tools.vsix. Reload the VS Code window if prompted.
Or install it from a terminal:
code --install-extension dist/hydrogen-language-tools.vsix
To replace an already installed copy with a newly built VSIX, run:
code --install-extension dist/hydrogen-language-tools.vsix --force
You can also build and install in one step with npm run install:vsix. Once installed, open a .hy or .hyproj file and confirm that VS Code shows Hylang or Hylang Project as the language mode. VS Code's VSIX installation guide covers the same UI and CLI installation methods.
Connect the compiler
Install a Hylang/Hydrogen hy compiler separately and make it available on PATH, or set its absolute path in VS Code settings:
{
"hylang.hyPath": "/absolute/path/to/hy"
}
The extension runs hy check on save. Use Hylang: Check Current File from the Command Palette to run it manually. Compiler errors appear in View > Problems. For projects with multiple source files, set a project target so the compiler checks the complete project:
{
"hylang.checkTarget": "MyApp/MyApp.hyproj"
}
The target path is relative to the open workspace folder. You can turn automatic compiler checks off with "hylang.enableCompilerDiagnostics": false; the manual check command remains available. If hy is missing or fails without recognizable diagnostics, open View > Output and select Hylang for details.
Formatting: Hylang: Format Current File and VS Code's Format Document command use hy fmt on a temporary copy of the file, then apply the result in the editor. This requires a CLI build with hy fmt, such as the C++ SDK. The released self-hosted compiler supports hy check but not hy fmt; on that compiler, formatting reports that it is unavailable and leaves the document unchanged.
