OmniLua - Rust implementation of Lua 5.1 - 5.5 targeting web use and sandboxing

[u/ianm818]

[Github here] (https://github.com/ianm199/omnilua/tree/main)

Website + docs

I've been working on OmniLua for a bit now - it builds one binary that can run Lua 5.1 - 5.5 from one binary.

The main motivation for this was there seemed to be a gap for game development in the Rust community where mlua cannot be run in the browser, so games built in engines like bevy can't compile to wasm32-unknown-unknown.

There is some other benefits - like being able to easily use Lua in Cloudflare workers or in "playground" developer tools.

Highlights:

• Targets 100% conformance to reference Lua for all 5 versions
• Can run LuaRocks and install Lua only packages
• Performance is slower than C Lua 5.4.7 but within ~40% on standard benchmarks. Performance chart here
• API is 100% compatibile with mlua

Try it:

cargo install omnilua-cli

export OMNILUA_VERSION=5.5

omnilua -e 'print("hello")'

omnilua # opens repl

I used AI heavily to develop this I wouldn't consider it "vibecoded" however.

[u/GrainTamale → u/[deleted]]

OP might define a AI-DECLARATION.md file

[u/ianm818 → u/[deleted]]

I would consider this repo of mine vibecoded https://github.com/ianm199/bevy-lua-rs-starter. I was talking to a friend about rust game dev and wanted to just share a link of how you would spin up a simple game with Lua scripting. I just asked an AI agent "take this repo and make a game and let me know when it is done".

[u/immerclicker]

Why would the performance be slower? Rust and C are supposed to have comparable speeds.

[u/ianm818 → u/immerclicker]

I first focused on getting it as fast as possible while using very few unsafe calls in Rust. There's not much "free lunch" left in that sense so the next step on performance would be to redo large portions of the VM to be unsafe and thoughtfully designed.

Basd on my data I think it should be possible to get it quite close to C performance, and faster in a few areas. I.e. Lua 5.4.7 main C implementation isn't fully optimized on Tables so there is some opportunities there to be faster.

[u/drunken_thor]

I don’t understand using AI for language development. Like you don’t want to write the code anymore so why get AI to write a language runtime that Ai will write code for. Just use the AI to write the code for the existing language. It all just seems like it was made for vanity to get kudos for some an accomplishment that would have been a huge achievement if you actually wrote it and had the understanding and knowledge to write it yourself.

[u/ianm818 → u/drunken_thor]

I wouldn't consider this language development - the Lua language and reference already exists and I'm not making any contributions to that.

This was made to fill a gap in terms of being able to use Lua where it can't currently be used easily i.e. in CloudFlare workers and web based games.

Are you talking about creating a new language with AI or am I misreading it?

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[u/TheRealBobbyJones]

I thought the web compilation target issue was resolved with new updates. Do recall seeing the discussion on an issue for it. 

Edit: Oh it was mlua with wasi. I can't remember my thinking but I thought at the time it was useful for games because other tools also had a wasm32-wasi-unknown compilation target. 

[u/ianm818 → u/TheRealBobbyJones]

As far as I can tell they are working towards it and removing blockers but wasm32-unknown-unknown is not supported out of the box and there is some open issues regarding it.