luau VS lua-cmake

As far as I can tell, they aren't.

http://lua-users.org/wiki/SandBoxes

There is a lot of information there, but it doesn't handle resource exhaustion, execution time limits or give any guarantees. It does indicate that it's possible, and has a decent example of the most restrictive setup, which is a good start. But I would for example compare it with Luau's SECURITY.md.

From https://github.com/luau-lang/luau/blob/master/SECURITY.md:

> Luau provides a safe sandbox that scripts can not escape from, short of vulnerabilities in custom C functions exposed by the host. This includes the virtual machine and builtin libraries. Notably this currently does not include the work-in-progress native code generation facilities.

> Any source code can not result in memory safety errors or crashes during its compilation or execution. Violations of memory safety are considered vulnerabilities.

> Note that Luau does not provide termination guarantees - some code may exhaust CPU or RAM resources on the system during compilation or execution.

So, even luau will have trouble with untrusted code, but it specifies exactly what happens and so on. I think that's fair enough.

Alternatively, Luau is a well-supported Lua variant with type checking and performance improvements, aimed more towards being a sandboxed embedded scripting environment.

https://luau-lang.org/

If you need Lua but also type-safety, how about Luau [1] then?

[1] https://luau-lang.org/

I had the pleasure of working with Lua 5.1 back in the late noughties. For me it's replaced Tcl whenever I want something I can configure above a C library. At the time I used it I found it quite nice but I'll also not forget the hours I wasted tracking down nil table corruptions which could have easily been caught by a type checker.

I had some hope that Luau https://luau-lang.org or Teal https://github.com/teal-language/tl would make things better but with the following example

    function foo(x: number): string

I use Luau in my games and tools [1], and I recommend it. While I can't speak to transitioning to it from Lua, since I didn't do that, I can say that it's fast, stable, sandboxing just works (important for your use case), and it's very well supported and regularly updated.

For context, I first started using Luau as an experimental hack by integrating it with Unity. I mostly just wanted fast and simple hot reloading. I found myself writing more and more of it, and now I'm writing most of my code in it.

VS Code support is pretty good via the luau-lsp language server [2]. Type support for certain code patterns isn't great yet, but there are RFCs to improve this.

They're also quietly working on native code gen and JIT support, e.g. this PR from a few hours ago [3].

Overall, recommended! You're not crazy.

[1] https://twitter.com/kineticpoet

[2] https://github.com/JohnnyMorganz/luau-lsp

[3] https://github.com/Roblox/luau/pull/1076

Looking at other replies here, I can see I wasn't the only one who didn't realize there is Lua and Luau. Luau is an extension of Lua: https://luau-lang.org/

> Luau is syntactically backwards-compatible with Lua 5.1 (code that is valid Lua 5.1 is also valid Luau); however, we have extended the language with a set of syntactical features that make the language more familiar and ergonomic.

Lua is usually the embedded language of choice. If you are focused on security, you could check out the Roblox fork, Luau (https://github.com/Roblox/luau) where the creators took extra care to lock down the language on what scripts could do.

Luau - Lua variant by Roblox

https://www.youtube.com/results?search_query=luau+roblox&sp=...

Luau

https://github.com/Roblox/luau

Roblox wrote a superset of Roblox Lua which is way faster

Lua is a very nice piece of technology. Its source code is pretty easy to get into, the documentation is complete.

It has its quirks yes, but if I need to add scripting to a software, I'd consider Lua before considering writing a DSL, simply because you can pretty much embed Lua's source in your C/C++ software as a static library[0].

The stack-based approach makes it so easy to interact with C/C++, and I've been looking at the Rust bindings[1] recently out of curiosity, looks promising.

  [0] - https://github.com/lubgr/lua-cmake