I only poked into the source code on github a bit, so I might be entirely wrong, but from what I understand, the original Lua runtimes (stock Lua, Luajit, etc) were modified for a new syntax? If so, what's the motivation for this approach? Since you already have an lua2ljs transpiler, wouldn't it be easier to use this knowledge to instead have an ljs2lua transpiler and just reuse all existing Lua implementations? Similar to how moonscript works?

Fair point but I prefer less code to mantain move around, as you pointed out it's only a moderate modification of the Lua lexer/parser and not need anything else ~200KB ljs, ~500KB LjsJIT interperter and there you go.

For some reason, it reminds me of Squirrel language[1] and Lemon language[2].

  [1] http://www.squirrel-lang.org/
  [2] http://www.lemon-lang.org/

I'm also forked the Squirrel at https://github.com/mingodad/squilu fixing some in my point of view missing features and making it accept a small subset of C/C++ language.

Maybe also properly separated list/array, map/dict and set types? The I-am-everything-{} type in lua is a bit unergonomic when you want to use it as only such a type and a stumbling block for unfamiliar users.

Can a project using 5.3 lua continue using existing .lua files but also write new files in .ljs?

> switch

Aren't match statements all the rage nowadays? Even C++20 get's one (with a silly name, of course)!

> class

Finally, setmetatable is nice, but, yes, "proper" not handrolled classes.

> const

Too few scripting languages have these. Do you intend to make this include interior mutability as well or is this only pointer deep?

The general idea is to be able to reuse code as much as possible, and C/C++/Java/Javascript style syntax make a lot of code available and if we ditch the 1 based index in favor of 0 based it makes it even easier.

It looks like it's still 1-based currently, is that right? 1-based arrays have been the biggest obstacle to me using Lua.

I did years of assembly, then C, and now Lua. I've yet to find the 1-based indexing to be an issue, and that's even having written a few C modules to manipulate Lua arrays. What is it about the 1-based arrays that is so off-putting?

Again the point is easy code reuse.

Yes you are right it's still 1 based to allow easy conversion from actual existing Lua projects.

FYI, the link for https://github.com/mingodad/raptorjit-ljs is down.

Congrats for the project, transpilers are great fun.

An impactful project and a logical next step would be writing a new version of Moonshine (http://moonshinejs.org/) or writing a modern full-blown Lua to JS transpiler.

Thank you for pointing it out. Fixed.

Cheers !

Who maintains LuaJIT these days?

Good question !

It seems that Mike Paul is still the main one that do it.

Now there is a repository on https://github.com/LuaJIT/LuaJIT/issues and after send a message to the mailing list and no answer for few days another user told me about it and I opened an issue of a problem I found while converting LuaJIT to LjsJIT see https://github.com/LuaJIT/LuaJIT/issues/461

Also, CloudFlare was "stewarding" the project (not sure what it exactly means) but they seem to be moving away their codebase away from Lua.

There’s also an active fork of LuaJIT called RaptorJIT that’s oriented towards building whole applications rather than embedding.

Interesting do you have any references about this?

These are a few years old:

https://news.ycombinator.com/item?id=9981802

https://news.ycombinator.com/item?id=10078848

They had a blog post about LuaJIT profiling just a couple of weeks ago https://blog.cloudflare.com/more-consistent-luajit-performan...

Have you considered a limited form of typescript transpilation?

Yes that's a nice goal and in order to have it we need "class/switch/enum/...", come onboard and help implement then.