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Hello, I'm trying to port over some libraries to kickstart prototyping on voxatron (such as 30log or cpml) and I got a weird issue with functions not finding an upvalue.

Let's say we have a B.lua file and a A.lua file
B.lua contains this:

B = {}

B_mt = {}

local function new()
    return setmetatable({}, B_mt)
end

function B.new()
    return new()
end

function B.draw()
    print("Called",0,0,7)
end

B_mt.__index = B
function B_mt.__call()
    return B.new()
end

B = setmetatable({}, B_mt)

It's basically a global class-ish definition with a constructor, an alias to the constructor via __index and the private constructor which is called internally.

Let's say we have an A.lua script which does:

local b = B()

function _update()
end

function _draw()
    b.draw()
end

It simply gets a B instance and calls its draw function yet it doesn't work on Voxatron 0.3.5. I don't know what are the private/public global/local stuff available on this platform but this kind of pattern doesn't work well. I get this kind of error.

In vanilla lua, it works pretty well, I can use dofile or require sequentially those files and call _draw() without error.

So I don't know if it's an error or a quirk designed by Voxatron limitations, but I'd like to know if it's intended and what are the extends of using local/global variables between scripts in Voxatron.

Thanks and have a nice day.

Edit : I'm calling those pseudo-modules because as we don't have Lua's module system, there are a few patterns that allows for psuedo modules to happen. They're just loaded during the cart initialization and in a sequential manner.

Edit 2 : For further indication, this is cpml's way of making classes.

P#60532 2019-01-03 16:28 ( Edited 2019-01-03 16:40)

B = setmetatable({}, B_mt)

You probably don't mean to be doing that after defining all of B's functions.

P#60533 2019-01-03 16:37

It still works because it's set to B_mt's __index. But I'm trying to simplify the bug case and it seems it also crashes without the metatable at all.

Using this code also doesn't work.

B = {}
local function new()
        return {draw = B.draw} -- ugly but only there to make the snippet work once it's fixed
end
function B.new()
        return new()
end
function B.draw()
        print("Called",0,0,7)
end

Update: it sounds like a scoping issue. Wrapping the code in a do/end scope works.

B = {}
do
local function new()
        return {draw = B.draw}
end
function B.new()
        return new()
end
function B.draw()
        print("Called",0,0,7)
end
end
P#60534 2019-01-03 16:45 ( Edited 2019-01-03 16:51)

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