What is _VERSION for?

Help and Feedback Scripting Support
#1

So you have _G which is global variable and _VERSION. What is it for?

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#2

The version of Lua implementation it’s running.
It’d return Luau (previously Lua 5.1) if ran on Roblox.

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#3 
print(_VERSION)
>Lua 5.1
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#4

So it’s pretty much useless? Welp thanks for help

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#5

It’s probably a bit useless for Roblox devs. It’s useful if you were writing Lua code that might be used outside of Roblox. It would let you change the way you program to know what features might be available. In Roblox, _VERSION returns Luau as @Blockzez said.

So if you were trying to make a module that might be used both on Roblox or outside of Roblox, you could use this information to change the structure of your code. For instance, if I wanted to create a function for finding the index of an item in a table, this would look different based on the version since Roblox provides a non-standard library function for it already:

function FindIndex(tbl, item)
	if (_VERSION == "Luau") then
		return table.find(tbl, item)
	else
		for k,v in pairs(tbl) do
			if (v == item) then
				return k
			end
		end
	end
end

In a similar light, you could do this to switch between the feature changes across standard Lua versions too (e.g. later versions of Lua include the bit32 library)

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#6

Though you can check if table.find exists in case you’re in an environment where table.find is included even if you’re not using Luau.

if table.find then
        return table.find(tbl, item)
end
for i, v in ipairs(tbl) do
        if v == item then
                return i
        end
end
return nil

Lua 5.3+ deprecated this and introduced bitwise operators.

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#7

Yeah you could switch like that too. But in some cases, you might have a full feature set of implementations and it’s easier to just check the version than every piece.

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#8

Building on to all the other posts here, _G means Global,
Here’s a post on that, it really fits well with this!

The _G post

What is _G and for what i can use it?

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