Question: how to deal with functions that return multiple values

[al1-ce]

Assume lua code:

local ok, ret = pcall(func, "something")

How would I translate it with js2lua?

[xiangnanscu]

I don't get it. This repo is about JS to lua, so JS will always return a single value for lua.

[al1-ce]

True, but I'm asking about how to deal in js with lua functions that return multiple values like pcall

I tried

let [ok, ret] = pcall(require, "somemod");

But it was generating something like

local ok, ret;
local __tmp = pcall(require, "somemod")
ok = __tmp[1]
ret = __tmp[2]

Which would produce errors since __tmp is not an array

I did found quick and dirty solution to that

function pack2(a, b) {
    return [a, b];
}

let status = pack2(pcall(require, "somemod"))

But it is indeed quick and dirty and it'd be preferable to have some sort of way to do it natively

[xiangnanscu]

I get it. On one hand, we would like to get local ok, ret = foo() from let [ok, ret] = foo() if foo is a common Lua function that returns multiple values (like pcall, xpcall, etc.). On the other hand, we might also want let [e1, e2, e3] = foo() to be processed in the current way if foo is a user-defined function that returns an array. Given this repo's slogan, "Writing LuaJIT with the expressiveness of JavaScript," functions like pcall should be specially handled, while other functions will be handled as usual. So JS code:

let [ok, ret] = pcall()
let [e1, e2] = my_func()

Will be:

local ok, ret = pcall()
local e1, e2
do
    local __tmp = my_func()
    e1 = __tmp[1]
    e2 = __tmp[2]
end

What's your opinion?

[al1-ce]

I've rarely seen non-std lua functions return multiple values so this is a good solution imo

[xiangnanscu]

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