Langium

Langium is a language engineering tool with built-in support for the Language Server Protocol. It has a simple and direct integration with the VS Code extension API.

More information: 🌍 https://langium.org

Getting Started

Langium offers a Yeoman generator to create a new language extension for VS Code. The only prerequisite for the following terminal commands is NodeJS version 16 or higher.

1. Install Yeoman and the Langium extension generator.

npm install -g yo generator-langium

2. Run the generator and answer a few questions.

yo langium

3. Open the new folder in VS Code (replace hello-world with the extension name you chose).

code hello-world

4. Press F5 to launch the extension in a new Extension Development Host window.

5. Open a folder, create a file with your chosen file name extension (.hello is the default), and see that validation and completion (ctrl+space) works:

Follow the instructions in langium-quickstart.md (in your extension folder) and the documentation on the website to go further.

How Does it Work?

The core of Langium is a grammar declaration language in which you describe multiple aspects of your language:

• Tokens (keywords and terminal rules)
• Syntax (parser rules)
• Abstract syntax tree (AST)

Please follow the Langium documentation to learn how to use this language.

Langium features a command line interface (langium-cli) that reads a grammar declaration and generates TypeScript type declarations for the AST and more.

Integration with the Language Server Protocol (LSP) is done with vscode-languageserver. You have full access to the LSP API in Langium, so you can register additional message handlers or extend the protocol in a breeze.

The main code of Langium consists of a set of services that are connected via dependency injection (DI). You can override the default functionality and add your own service classes by specifying a DI module.

Examples

The source repository of Langium includes examples that demonstrate different use cases.