What is Langium?

In this article, we review what languim is and how LikeC4 built language server using the Langium library. We will look at:

1. What is Langium?

2. likec4/language-server

What is Langium?

Langium is an open source language engineering tool with first-class support for the Language Server Protocol, written in TypeScript and running in Node.js.

I skimmed the important parts in the Langium docs and this is how the Langium’s workplace:

Langium’s workflow can be expressed as a flow chart diagram, which boils down to the following steps in the diagram. Be aware of the fact that the possibilities go beyond this simple workflow. For more advanced topics, you can find answers in the recipes.

I do recommend to check out the docs for next steps.

likec4/language-server

likec4/language-server is a Language Server Protocol (LSP) based on langium library.

Usage

npm install -g @likec4/language-server
likec4-language-server --stdio

Valid arguments:

• --node-ipc

• --stdio

• --socket={number}

import { startLanguageServer } from '@likec4/language-server/bundled'
startLanguageServer().catch((e) => {
  console.error(e)
  process.exit(1)
})

In the like-c4.langium file, I saw the langium grammar defined.

About me:

Hey, my name is Ramu Narasinga. I study codebase architecture in large open-source projects.

Email: ramu.narasinga@gmail.com

I spent 200+ hours analyzing Supabase, shadcn/ui, LobeChat. Found the patterns that separate AI slop from production code. Stop refactoring AI slop. Start with proven patterns. Check out production-grade projects at thinkthroo.com

References:

1. langium.org/docs/introduction/#where-to-go-from-here

2. langium.org/docs/learn/workflow/

3. likec4/likec4/…packages/language-server/README.md

4. likec4/likec4/…/packages/language-server/src/like-c4.langium