support tuple type

[lizho]

Support annotation of tuples by using square brackets.

---@type [string, integer]

[sumneko]

Thank you very much for your PR. I'd be happy to add this feature. However, based on my past experience, I suggest that you first enable this feature locally, use it in the actual project for about a week, confirm there are no obvious issues, and then let me know to merge. I've been quite busy with work lately and don't have much time to test this feature.

[lizho]

It has worked for a while now.

In fact, I'm working on another feature about variadic generic annotations in a way kind of similar to C++.

For example,

---@generic ...T
---@parameter ... T...
---@return [T...]
function tuple(...)
end

local t = tuple(1, "2", false) ---> `t` is the same as marked as @type [integer, string, boolean]

Furthermore, a more complex use is,

---@generic ...T
---@parameter ... T[]...
---@return fun(): T...
function zip(...)
end

---@type integer[]
local a
---@type string[]
local b
---@type table[]
local c

for i, s, t in zip(a, b, c) do
---[[
    in which,
    `i` -> integer,
    `s` -> string,
    `t` -> table
---]]
end

[sumneko]

Generics are very complex, and the current implementation is not quite right. I suggest you not to put too much effort into it for now.

[eigenbom]

Thanks for implementing this! It helps me a lot with #1816

One thing I noticed is a conflict between subarrays and lua strings. The first form works, the second gets confused.

I'm not sure what a good resolution here is, but the second form is an invalid lua string (as the type annotations don't seem to allow multi-line params here..?) so it probably should be inferred as a tuple type.