Building an LSP Server with Rust is surprisingly easy and fun

In the past few weeks, I've been on the lookout for a solution to share code between multiple editors and platforms. I'm working on a CodeOwners platform, and part of the offering is various integrations with developers' own editors (like Visual Studio Code, neovim, Zed, etc.) and potentially LLM agents. Though I knew from the start that each editor would need its own integration, the pattern matching logic for CODEOWNERS rules stays the same across all of them; and it was important that this code produce consistent results whether it ran in Lua or Rust. So the challenge was twofold: how to keep this logic consistent across platforms and languages, and how to keep it in sync when making updates. One idea was to use WebAssembly to encapsulate the logic, ensuring the same code handles pattern matching everywhere. However, there was another challenge: speed. Since the CODEOWNERS CLI reads every file to find ownership data, this part can't be done in WASM and has to live in each editor's o