How can I tell this function that it returns a metatable?

Help and Feedback Scripting Support
#1

Hi,

So , Im wondering how I could say a type is a metatable, as when you return a metatable, it would look something like this in script:

{ @metatable a, {- -} } 

-- when making a metatable using `setmetatable`
-- it tells you that it returns this item which
-- is the metatable.

So, I’m wondering how I can do this in this script? If its even possible?
Because when using --!strict, it gives you warnings about how things are returning when you give it something to expect.

--!strict

type SomeData = {} -- How can I make this type a metatable?

local module = {} -- module table

function module.example(): SomeData -- function 'returns' the custom type
    local self = setmetatable({}, {__index = module})

    self.self = self -- lol

    return self -- using --!strict gives me a warning about the return
end
2 Likes
#2

Would the issue still happen if you changed the name of the local variable? (from “self” to somthing else)
Probably isn’t the isssue, but figured I’d suggest it.

#3

Not really an issue, just asking how I can make this type a metatable, but thats not really how that works.

#4

There isn’t really a way (that I know of) that does what you want cus one thing stops the other from working so it won’t be so good.

#5 
local module = {} -- module table

function module.example(): SomeData -- function 'returns' the custom type
    local self = setmetatable({}, {__index = module})

    self.self = self -- lol

    return self -- using --!strict gives me a warning about the return
end

type SomeData = typeof(module.example())

I believe this should get the script editor to play nicely with the metatable.

2 Likes
#6

Bad to do this.
That disables the autocomplete for methods so that didn’t fix anything.

That’s exactly what (s)he’s trying to avoid.

#7

Forget that I managed to fix it. Try this:

--!strict

local Class = {}
Class.__index = Class

type Data = {
	a: number,
	b: number,
}
type Class = typeof(setmetatable(({}), Class)) & Data

function Class.new(a: number, b: number): Class
	return setmetatable({
		a = a,
		b = b,
	}, Class) :: Class
end

function Class.Sum(self: Class): number	
	return self.a + self.b
end

local class = Class.new(2, 2)
class:Sum()

return Class
1 Like
#8

I don’t know what is happening on your end, but autocomplete works perfectly fine.

But isn’t that what’s exactly in the post?

#9

Weird.

I don’t get what you mean by this but your avoiding the usage of --!strict and:

#10

The code wont recognize the module.example because it is trying to fire something that doesnt exist yet, and using Global Variables also causes Warnings, which is what I want to avoid

After Edit:
I don’t think that would work with arguments.

#11

Fixed the ordering of things, but using global variables don’t cause warnings?

image
image747×317 11.3 KB

#12

To be more specific:

var = {}        -- Global Variable
local Item = {} -- Local Variable
#13

There are no global variables instantiated in the code at all.

Correct, it does need a little bit more modification.

--!strict

local module = {} -- module table

function module.example(x : number, y: number): SomeData -- function 'returns' the custom type
	local self = setmetatable({}, {__index = module})

	self.x = x -- lol
	self.y = y

	return self -- using --!strict gives me a warning about the return
end
type SomeData = typeof(module.example(table.unpack(...)))
local a = module.example(2, 3)
print(a.x)
print(a.y)
1 Like
#14

That seems to work, as im no longer getting any warnings, but im not entire sure if that is the best way to do it.

Edit: Not really, got the same warning again.

#15

What warnings? I had 0.
There’d no other way to do this but if you find one do let me know.

#16

This works

local function ClassPrototype() -- You define all the properties you want your class to have here
    return {
        Property = true;
    }
end

local Object = {}
Object.Class = {}
Object.Metatable = {__index = Object.Class}

function Object.new(): typeof(setmetatable(ClassPrototype(), Object.Metatable))
    local NewObject = ClassPrototype()

    return setmetatable(NewObject, Object.Metatable)
end

function Object.Class:Method()

end

local NewObject = Object.new()
local Property = NewObject.Property
NewObject:Method()
#17

Well, I cannot test this rn, so I’ll have to do it later.
Also, I wasn’t asking for wntire code.

#18

Doesnt really seem to work, but this is what I want to do:

Change the function from saying this:

example(...): { @metatable module, {...} }

to saying this:

example(...): SomeData -- Looks much cleaner

but since the item its returning is a metatable, and not an ordinary table, im not sure how I can do this change.

#19

You should explain what doesn’t work because it’s a little hard to help you otherwise.

“SomeData” can be a type you define somewhere in your code, doesn’t matter where but you have to define it. Something like

type SomeData = typeof(setmetatable(ClassPrototype(), Object.Metatable))

somewhere at the bottom also works.