feature/impl-luau-lib: Add support for luau.compile and luau.load.

[4x8Matrix]

Context

Lune at the moment has no way to optimally run source/bytecode, this PR aims to try and implement a new luau library that allows developers to create Luau closures in their code.

This PR attempts to bring together some of the points made in [RFC] Lune built-in luau library, however, discards the seySafeEnv function call as i'm not certain how we'd go about doing that under mlua

(Would be happy to discuss this though!)

This PR

• Implement a luau Lune library.
• Implement luau.compile function to compile a string into bytecode.
  • Implement an optional options table allowing developers to set optimization_level, coverage_level and debug_level
• Implement luau.load function to load either bytecode or a source string into a function.
  • Implement an optional options table allowing developers to set debug_name.
• Implement tests for the luau Lune library
• Add documentation types for luau Lune library

Yet to-do

• N/A

[filiptibell]

Left a few comments - I think everything looks pretty good, not sure exactly how we would expand the testing suite here, but if you think of anything feel free to add some more tests since this is such a low level feature.

[filiptibell]

Is there any way to verify that this is actually bytecode and not an arbitrary string? Does Luau bytecode start with any specific magic header or somesuch?

[4x8Matrix]

From what I can tell - Luau bytecode does start off with the version of the bytecode, but the bytes after that go into the content of that bytecode.

<bytecode-ver> ...

I've found this from both of these sources;

• https://github.com/uniquadev/LuauVM/blob/master/VM/luau/lvmload.lua
• https://github.com/Roblox/luau/blob/bd229816c0a82a8590395416c81c333087f541fd/VM/src/lvmload.cpp

[4x8Matrix]

Edit: Additionally, if a compilation fails - instead of producing an error, the luau.compile function will return a message where the first byte is 0, and the error is attached afterwards. (luau.load accounts for this, but i'll get it tested none-the-less!)

[filiptibell]

Additionally, if a compilation fails - instead of producing an error, the luau.compile function will return a message where the first byte is 0, and the error is attached afterwards

I think it would probably be a good idea to check for this on the rust end of things for the compile function and throw a lua error then, too. We don't really have any other APIs that behave like this in Lune where they return an error message, if the user wants to handle errors/fallible functions pcall should be the go-to for consistency

[4x8Matrix]

I've made the above changes in b5906b2

[filiptibell]

Additionally, if a compilation fails - instead of producing an error, the luau.compile function will return a message where the first byte is 0, and the error is attached afterwards

I think it would probably be a good idea to check for this on the rust end of things for the compile function and throw a lua error then, too. We don't really have any other APIs that behave like this in Lune where they return an error message, if the user wants to handle errors/fallible functions pcall should be the go-to for consistency