kiwi VS luau

Nucleic also makes Kiwi one of the fastest Cassowary Constraint implementations. It is very useful for implementing custom GUIs as it can make building internal component layouts and general layout systems fairly straightforward and it’s very performant.

I highly encourage taking a look at it and it has also been ported to a wide range of language.

I’m using Nim kiwi with my own GUI library now. I’ll have to take a peak at how enaml is using kiwi for its layouts.

https://kiwisolver.readthedocs.io/en/latest/

https://github.com/alexbirkett/kiwi-java

https://github.com/PongoEngine/jasper

https://github.com/yglukhov/kiwi

If any of the Luau devs are watching this, please flesh out the metamethods. I'd switch almost everything to Luau if they were improved.

They're the biggest PITA right now as designed in PUC-Rio, and I see that while you've improved upon __eq, other metamethods are still lacking.

In PUC-Rio, boolean equality operators FORCE a boolean result, regardless of what you return. Ideally they would allow returning any result type, which then can be coerced to boolean later (e.g. by an `if` statement), just like the arithmetic operators do.

Further, `__neq`, `__ge` and `__gt` do not exist. They should.

The lack of a proper metamethod design means that binding to e.g. Kiwi[0] is impossible without some incredibly fugly hacks. It has been a long-standing annoyance with Lua in an otherwise beautiful little scripting language (that I use frequently).

This looks quite nice - lots of attempts in this space but nothing that attempts to match Lua to this degree.

[0] https://github.com/nucleic/kiwi

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