> The thing that people who don't really know Lua don't get is that Lua doesn't give a shit whether you start at 1 or at 0.
I don't really understand why this claim comes up all every time in these discussions, it's obviously not true. Like one of the most important operations with an dynamic array is figuring out it's length (and not by iterating over all of it). This breaks if you don't use 1-based.
Lua's length implementation is a big complex iterative search because "length" isn't even defined as the length of the object but rather the length of the first contiguous sequence of non-nils, so good luck applying that premise!
The "length" function in Lua is an extremely annoying footgun, but nothing you said is an argument for indexing non-arrays starting from 0.
Vanilla lua does a logarithmic search (still much better than a linear scan you'd get with ipairs), but I don't think that's typically true in luajit, although I admit I might be quite wrong about this.
Here is some relevant Luajit code: <https://github.com/LuaJIT/LuaJIT/blob/v2.1/src/lj_tab.c#L690... it definitely seems to do a constant time lookup for the length in some cases only falling backing to binary search if the array contains no valid length hint. Also, I'm pretty sure most of the linear algebra libs I've seen overload # for vector/matrix/array classes (and give O(1)); IIRC it's also not at all uncommon to do that if you create some C array backed data structure via luajit's FFI. Regardless of "length" the fact that e.g. ffi.new("double[3]") will be zero and not one based is already a major source of friction.
In any case, in my opinion there is not first and foremost a problem with "length" as such. I think the overalll conclusion is that the fairly bold move to have a single all-purpose hybrid container data structure was not a success and is not something that other languages should try to replicate. Even luajit fails to make this work really well, despite heroic efforts.
> the fairly bold move to have a single all-purpose hybrid container data structure was not a success and is not something that other languages should try to replicate
I agree with this. It created more complication than it reduced. But the length operator is still additionally terrible and does something other than what most people want.
I don't really understand why this claim comes up all every time in these discussions, it's obviously not true. Like one of the most important operations with an dynamic array is figuring out it's length (and not by iterating over all of it). This breaks if you don't use 1-based.