I've taught programming to beginners, both children and adults, and lua is the worst of the languages I've done it with. It's an amazing technical accomplishment, and CS students should study its implementation. But for actual beginners its "focus on fundamental concepts" and flexibility are liabilities.
The main struggle people have learning to code is getting over the initial frustration hurdle where they can't actually accomplish anything yet. What they have to get them through this is excitement about their actual goals. With lua you burn too much goodwill and beginner spark on debugging string manipulation functions that don't seem important to the actual interest or goal that brought them to programming. Or figuring out how to use luarocks so you can make http requests, or regex, or whatever.
> 1-based indexing could cause beginners to get confused when they move to another language.
This is so far from the problems that beginners actually have. You should teach some programming, it's a really fascinating experience that will mess with your intuitions about how people learn this skill, and what's hard about it.
I remember telling my friend to start his brother on ApplesoftBasic because its batteries included, has no files or libraries, you just do some math and print and draw colored dots and lines and I trained two people like that on an Apple][ emulator with good results.
My friend was like "no way. im gonna start him with something simple like html."
Within seconds he realized he had to explain what paths were, and his brother struggled so much with them. My friend took for granted what he had already spent time learning. He was unable to guess what would be difficult to understand without priors.
Walled gardens like Processing seem to be better for education.
I would absolutely never, EVER encourage the use of a package manager when getting someone accustomed to programming. Why on earth would you do that? The problems that package managers solve are completely orthogonal to the environment of someone who hasn't even built up the intuition for basic things like flipflops, lexical scope, iteration, etc.
Downloading archives with a web browser and extracting them and just doing manual file management is vastly preferable in such an environment. That is a vastly simpler process which is impossible to break, and odds are the student will already be familiar with most of the process.
Interesting viewpoint. It is my belief that Lua would be nice as a first language, but maybe this opinion is tainted by all my years of experience in programming. Lua definitely wasn't my first language, I started out with C/C++ and Java, long ago. Nothing beats having first-hand experience as a teacher and thus I'll accept your opinion as something more substantiated than my gut feeling.
I'm quite interested in this topic, since I would like to write a good book to introduce absolute beginners into the world of programming. I have a good and encompassing knowledge about many different languages, nevertheless I lack teaching experience.
In your opinion, which languages are good candidates as a first choice and what do you think about using a Lua game framework, like for instance Love2D to teach programming (instead of raw standalone Lua)? The idea being that instead of clunky low level awkwardness, like string manipulation, students would instead see geometrical shapes moving on a screen with just a bunch of simple and imperative statements. Would that provide a better motivation?