Lua is a little confusing language for me because you need to throw out most of the things you know because it has its own way of doing things, it is not necessarily a bad thing but it is confusing. Luckily, it is a very small language so it wouldn't take that long to grasp it all. The most confusing thing was the fact that (almost) everything seems like a hashtable.
ebg13|5 years ago
The main thing you need to know is that Lua's table type can be numerically iterated between index 1 and the first gap where numeric index has nil value using the ipairs iterator in addition to the non-exclusively-numeric unordered pairs iterator. A common pitfall with sparse tables is that the length shortcut # returns seemingly the wrong result if you aren't aware of that first part.
Most of the difficulty writing in Lua comes from the fact that there's no first class support for OO-style Classes, so you have to fake them, and there's no standard library so you end up reinventing a lot.
But other than that, it's a dead simple language with few features.
grawprog|5 years ago
Metatables are cool, but have some weirdness to them. For OOP i ended up using metatables to make a simple prototype(rather than class) based system, but it was hacky at best.
Tables themselves are pretty awesome and powerful, but I have to admit, working with them gets a bit tiresome in ways working with dedicated arrays and hash maps don't. You have to remember exactly what kind of data is in your tables and looping through them can be a pain.
Overall though, I still love lua, it's the language that helped me 'get' programming and I wouldn't actually appreciate dedicated data structures and typed variables so much if I hadn't had the experience of starting with a more free, loose and simple language like lua. Also, its ability to easily interface with C and be easily embedded has made it appear in so many different and sometimes strange and just downright cool applications.
I've been playing with the solarus engine lately, it uses lua for its scripting, it's the first time I've written any lua in a while, but i've been enjoying it as I rediscover all the little cool things I like about it and i still think it makes a good first or second language for people.
Having the reinvent the wheel isn't necessarily a bad thing when you're learning. That hacky prototype system I made helped me understand OOP far better than just using classes in other languages had. Even if it didn't really work all that well in the end. It really made me appreciate what a built in class system actually gives you.
joe-collins|5 years ago
My pet peeve is that it's somewhat verbose in using keywords rather than single-character punctuation to mark blocks and clauses.