Show HN: Glua, a Full-Featured Lua VM for Nodejs and the Browser | Hacker News Reader

Show HN: Glua, a Full-Featured Lua VM for Nodejs and the Browser

github.com

70 pointsfiatjaf17 comments

This suffers from the same issue as https://daurnimator.github.io/lua.vm.js/lua.vm.js.html and others: there is 2 GC working side by side and it's bound to lead to never freed objects.

This isn't just because of 2 GC's working side by side. This happens to any memory that isn't a JavaScript object. So every asm.js and WebAssembly library is affected by the same issue, even if it doesn't have its own garbage collector. With there no way of hooking into JavaScript's Garbage Collector, you can't free your native handles when the JavaScript object wrapper gets collected, so you get leaks all over the place. So the only option is to manually manage your JavaScript objects in your JavaScript code by calling their "destructors", which kind of defeats the whole purpose of having a Garbage Collector. With WebAssembly on the rise, I hope people become more aware of this issue and implement proper GC Hooks for JavaScript.

There is also one in WebAssembly: https://github.com/vvanders/wasm_lua

This seems to be a thin wrapper for the actual Lua VM implemented in Go: https://github.com/yuin/gopher-lua

So Lua to Go, and Go to Javascript. I wonder how well that works..

Well, the original Lua VM is written in C, so it's more like C to Go to JavaScript.

This description made me chuckle. It reads to me like someone was intentionally concocting the most complex and least efficient method of programming a computer.

I come from a game development background and my view on things is admittedly affected by having to deal with issues related to real time efficiency.

Really cool! Reminds me of another awesome Lua->JS project called starlight: http://starlight.paulcuth.me.uk

I'd love to see a framework that treats client/server code as Ring 4 and Ring 5. you just have one codebase for client and server and it's up to the programmer to decide what it can trust the client side to compute.

What's the context for "Ring 4" and "Ring 5"? Are these some multitier architecture terms?

I suppose it has to do with https://en.wikipedia.org/wiki/Protection_ring

I find it kind of a funny that over-engineering lost, same as in OSI versus TCP/IP. 7 layers vs 4, 4 rings available vs 2 rings actually used.

Funny, but the lesson is never learnt until late in life.

To paraphrase Aristotle: "Only achieve that which is sufficient".

Ironic that Lua was designed to be as simple as possible and no simpler (was that Einstein?) and then it gets layered (laid, layed?) over ponderous systems that it really should be replacing.

And finally, complying with the rule of three and layering (pun) upon dijkstra's proposition: "layers should be considered evil".

Personally, in software, everything should be compiled to machine code if not already written in it, optimised to remove function calls and loops and at run time ensure that all data fetches control movements use the nearest memory.

The idea is interesting, but I doubt it'd be actually useful. If you're running code that doesn't require access to specific browser features, why run it on the client at all? It's generally less reliable, often slower, incurs serialization costs, etc.

Has this been tried with emscripten and regular Lua?

Yes [0]

[0] https://news.ycombinator.com/item?id=5794772 | http://mozakai.blogspot.com.au/2013/05/lua-in-javascript-run...

Yes: https://daurnimator.github.io/lua.vm.js/lua.vm.js.html

Reply on news.ycombinator.com