fengari VS luau

it should be possible, the article mentions https://fengari.io/ (a Lua VM written in JavaScript)

Check out Fengari or Lapis. Fun fact: itch.io is written primarily in Lua, and started by the same person who made Lapis and MoonScript.

I was real excited to see these recently... have you tried any? https://fengari.io/ is the one I was most intrigued by.

Hello, there is also fengari: https://fengari.io/

Other languages have done that :)

Lua in the browser: https://fengari.io/

And then you can use that to run Fennel, a Lisp that compiles to Lua https://fennel-lang.org/

I think TypeScript also has a script you can include that lets you put your TS code in a special script tag, and it gets compiled in-browser.

just use lua, it’s what should have been used for web scripting anyways

Please stop this stuck in the mud nonsense. Anyone stumbling upon lua.org might think the project is dead already. The material is great, close to the best, but its presentation is pure shite. Not mobile friendly (what kinds of device do you think the majority of people in the Global South use?). We live in a world of code highlighting, none of that in PiL. We live in a world where Fengari allows Lua to run in the browser, does that make an appearance on lua.org, allowing users to immediately play with the language? Of course not! It's almost as if the Lua team is trying to push away potential users.

why not use lua

Just use lua https://fengari.io/

Definitely the most surprising use-case for Lua that I've seen is http://lua.space/webdev/why-we-rewrote-lua-in-js which discusses https://fengari.io/.

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

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

On a side note, I've heard that they recently switched from Lua to Roblox's own fork of Lua, Luau.

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

https://luau-lang.org/ - some documentation, and examples https://create.roblox.com/docs - documentation, tutorials, and examples https://www.youtube.com/user/AlvinBLOX - tutorials https://www.youtube.com/@TheDevKing/videos - tutorials https://www.lua.org/manual/5.1/ - not specific to Roblox, but Lua reference manual https://www.codecademy.com/learn/learn-lua - Lua on Codecademy