While many languages follow a 0-indexed convention, as you see here, not all do. Another couple of cases I run into are Postgres arrays, and switching between “first”, “second”, and “nth” in Clojure.

If it helps, you can think 0-indexed as referring to the offset, and 1-indexed as referring to the position. It’s a shame to dismiss the entire language due to what one might argue is a minor aspect.

I would not call Clojure 1-indexed though because of 'first', it uses 0-indexing for list, vectors, and arrays.

To be clear, I’m not calling Clojure 1-indexed: I provided “nth” and “first” as examples of contrasting 0- and 1-based conventions; in this case within the same language.

Clojure being a lisp also has different enough syntax it is easier to jump back and forth because you're doing way more context switching. Lua looks enough like other c-style languages you can forget it is 1 based and make all sorts of nasty mistakes.

You can certainly argue it is unfair, but it is still something that increases the risk of mistakes.

Replacing (first coll) by (nth 1 coll) in clojure happens to me more often than I'd like to admit

I mostly write in Java for work. Back to the good old high school days, I spent 2 years learning programming in Pascal (yes, Turbo Pascal for DOS!), so seeing arrays started at 1 is not something strange for me :)

Of course, in Pascal you actually can pick any number where the index starts/end.

Totally agree with you. Zero-indexed arrays are one of those language design dogmas that are simply set in stone, really awkward to switch between languages when Lua has such a fundamental difference of opinion.

They don't have to, since Lua tables are hash sets and you can use anything as a key. You can start them at 0 if you want. table[0] = "foo" is valid and works. The downside is you have to add '-1' in a few places, but it's not as many as you'd think. All of my Lua code uses zero based arrays. I think the only place I had to add -1 was initializing numeric for loops.

Since Lua “arrays” are just tables with numerical keys, couldn’t you just start at 0 if that’s your preference?

For me it was the fact that the array ends at the first 'nil' you store in it. 1-based arrays I could get used to; that was just maddening.