The Power of Lua and Mixins • Hacker News Board

Re: The Power of Lua and Mixins

#11

Post by bartbes » Sun, Apr 06, 2014, 1:30 PM UTC

kephra wrote: post #8

It would be better if this article had been using real Lua code, and not starting with a "class" function. Lua does !NOT! have classes. Lua is a prototyping language, and anybody can handwave an own class system, or go without classes at all. The idea of mixins makes only sense in languages that have classes. Lua does not. References have a metatable, and this metatable contains functions. The functions are independe…

Yet the very first sentence of the article mentions the class library he's using for the rest of the it.

Re: The Power of Lua and Mixins

#12

Post by mantrax4 » Sun, Apr 06, 2014, 2:07 PM UTC

veb wrote: post #10

Wait. Just having a glance at the website, and I see these animations - do they have anything to do with the code? It doesn't quite clearly state that and I'm kind of put off reading the code. :-/ Sorry if I've missed something.

Lua's most popular use is for scripting game engines. From simple side scrollers to powerful FPS 3D engines.

So it's basically like "a taste of the world of Lua" or something like this, to make the presentation less dry.

Re: The Power of Lua and Mixins

#13

Post by exizt88 » Sun, Apr 06, 2014, 2:16 PM UTC

Udo wrote: post #4

I've bee studying Lua very thoroughly recently because I'm working on a toy language based on its runtime, so I gained a certain appreciation for some of the concepts Lua uses. Given this background and my general coding experience up to now, I'm very skeptical about OO frameworks for Lua, because they mostly provide mechanisms that are neither true to the language's design nor are they really necessary. Specifically…

Not bashing PHP in any way (I'm a PHP developer myself), but what would you consider the PHP paradigm?

Re: The Power of Lua and Mixins

#14

Post by Udo » Sun, Apr 06, 2014, 2:48 PM UTC

exizt88 wrote: post #13

Udo wrote: post #4

I've bee studying Lua very thoroughly recently because I'm working on a toy language based on its runtime, so I gained a certain appreciation for some of the concepts Lua uses. Given this background and my general coding experience up to now, I'm very skeptical about OO frameworks for Lua, because they mostly provide mechanisms that are neither true to the language's design nor are they really necessary. Specifically…

Not bashing PHP in any way (I'm a PHP developer myself), but what would you consider the PHP paradigm?

I like PHP as well, however it's the wrong language to build byzantine OO inheritance structures in. Yet, that's what new feature development seems primarily directed at: new OO functionality that adds a lot of complexity and new opportunities for developers to shoot themselves in the foot. Listening to PHP core developers' presentations, I get the impression they're trying to imitate Java.

The per-request execution model can be played as an incredible strength, but the moment some framework comes along, starting off by loading all of its code, then instantiating a myriad classes, subclasses, traits, and other crap just to serve a simple request - that's where slowness and bugginess comes from.

I think simple objects do work well in PHP, together with judicious use of the powerful array data structure, anonymous functions, and on-demand code loading.

Re: The Power of Lua and Mixins

#15

Post by yp_master » Sun, Apr 06, 2014, 3:14 PM UTC

  1 notmagi.me:
  55 bytes, 1+1+0+1 records, response, authoritative, noerror
  query: 1 notmagi.me
  answer: notmagi.me 1800 A 207.97.227.245
  additional: . 32768 weird class

Nice.

Re: The Power of Lua and Mixins

#16

Post by octopus » Sun, Apr 06, 2014, 3:40 PM UTC

kephra wrote: post #8

It would be better if this article had been using real Lua code, and not starting with a "class" function. Lua does !NOT! have classes. Lua is a prototyping language, and anybody can handwave an own class system, or go without classes at all. The idea of mixins makes only sense in languages that have classes. Lua does not. References have a metatable, and this metatable contains functions. The functions are independe…

Best Lua "class" example I've seen is in the PIL 3rd edition it is about 10 lines of code and lets you use inheritance and some other nice OOP concepts.

Re: The Power of Lua and Mixins

#17

Post by kzrdude » Sun, Apr 06, 2014, 4:30 PM UTC

kephra wrote: post #8

It would be better if this article had been using real Lua code, and not starting with a "class" function. Lua does !NOT! have classes. Lua is a prototyping language, and anybody can handwave an own class system, or go without classes at all. The idea of mixins makes only sense in languages that have classes. Lua does not. References have a metatable, and this metatable contains functions. The functions are independe…

This is a boring view! All the same concepts of classes, interfaces, objects still exist when using Lua, you just don't have a canonical implementation. This is also interesting in itself -- the best class system may spread and be improved.

Re: The Power of Lua and Mixins

#18

Post by kzrdude » Sun, Apr 06, 2014, 4:31 PM UTC

sieisteinmodel wrote: post #3

Animated pictures of a Jump'n'Run game make blog posts really hard to read. Might be related to the way human attention works, but well.

It's not unrelated, there's a hammer animation after the Hammer class, and dust after Dust.

Re: The Power of Lua and Mixins

#19

Post by otikik » Sun, Apr 06, 2014, 4:37 PM UTC

Udo wrote: post #4

I've bee studying Lua very thoroughly recently because I'm working on a toy language based on its runtime, so I gained a certain appreciation for some of the concepts Lua uses. Given this background and my general coding experience up to now, I'm very skeptical about OO frameworks for Lua, because they mostly provide mechanisms that are neither true to the language's design nor are they really necessary. Specifically…

Hi there,

I am the author of the OOP library mentioned on the article.

> I'm very skeptical about OO frameworks for Lua

Me too :)

I think Lua OOP libraries are great in two particular circumstances: for people coming from OOP languages, when starting working with Lua, they serve as a "crutch"; they allow you to start working in a language with paradigms that you are not familiar with with a set of structures you are familiar with.

Later on, once you are familiar with Lua's metatables, you can do most things with plain Lua. 90% of the time, it's just enough.

The remaining 10% comes when you need really advanced stuff - for example, class methods called the same as instance methods in class. Or operator inheritance. Then using a library like middleclass is worth the increase in complexity and the extra dependency.

TL;DR: Use middleclass at the beginning, when you are learning, or at the end, when you need advanced stuff. Don't use it if you just need 1 line of metatable stuff and you know how to implement it in raw Lua.

Re: The Power of Lua and Mixins

#20

Post by otikik » Sun, Apr 06, 2014, 4:50 PM UTC

kephra wrote: post #8

It would be better if this article had been using real Lua code, and not starting with a "class" function. Lua does !NOT! have classes. Lua is a prototyping language, and anybody can handwave an own class system, or go without classes at all. The idea of mixins makes only sense in languages that have classes. Lua does not. References have a metatable, and this metatable contains functions. The functions are independe…

Hi,

I am the author of the library mentioned in the article (not the article author, that's someone else). You seem to have missed the link to the OOP library used, so here it is:

https://github.com/kikito/middleclass

Also, notice that in other comments on this thread I mention that I don't think OOP in Lua it's a one-size-fits-all thing. I think middleclass has its uses, but most of the time plain Lua with some metatables does the trick just fine.