Metatable

The metatable functions allow elevated access to locked metatables.

---

getrawmetatable

function getrawmetatable(object: table): table

Returns the metatable of object, where the __metatable field would normally lock the metatable.

Parameters

• object - An object with a metatable.

Example

local object = setmetatable({}, { __metatable = "Locked!" })
print(getmetatable(object)) --> Locked!
print(getrawmetatable(object)) --> table

---

hookmetamethod

function hookmetamethod(object: table, method: string, hook: function): function

Replaces func with hook internally, where hook will be invoked in place of func when called.

Returns a new function that can be used to access the original definition of func.

⚠️ Not yieldable

The function hook is not allowed to yield or block the thread.

⚠️ Recursion

Try not to invoke method from within the function hook! For example, do not index a property of an Instance from within a hook to __index.

Parameters

• object - An object with a metatable.

• method - The name of the method to hook.

• hook - The function to replace func with.

Example

Prevent scripts in PlayerGui from invoking the __namecall hook:

local refs = {}
local bannedScripts = game:GetService("Players").LocalPlayer.PlayerGui

refs.__namecall = hookmetamethod(game, "__namecall", function(...)
	local caller = getcallingscript()

	-- Use '.' notation to call the IsDescendantOf method without invoking
	-- __namecall and causing a recursive loop.
	local isBanned = caller.IsDescendantOf(caller, bannedScripts)

	if isBanned then
		error("Not allowed to invoke __namecall")
	end

	return refs.__namecall(...)
end)

---

getnamecallmethod

function getnamecallmethod(): string

Returns the name of the method that invoked the __namecall metamethod.

Example

Bans the use of game:service():

local refs = {}

refs.__namecall = hookmetamethod(game, "__namecall", function(...)
	local self = ...
	local method = getnamecallmethod()

	if self == game and method == "service" then
		error("Not allowed to run game:service()")
	end

	return refs.__namecall(...)
end)

---

isreadonly

function isreadonly(object: table): boolean

Returns whether object is frozen or read-only. Identical to table.isfrozen.

Parameters

• object - A table or userdata.

Example

local object = {}
table.freeze(object)
print(isreadonly(object)) --> true

---

setrawmetatable

function setrawmetatable(object: table, metatable: table): ()

Sets the metatable of object to metatable, where the __metatable field would normally lock the metatable.

Parameters

• object - A table or userdata.

• metatable - The metatable to set.

Example

local object = setmetatable({}, {})
print(getmetatable(object)) --> table
setrawmetatable(object, { __metatable = "Hello, world!" })
print(getmetatable(object)) --> Hello, world!

---

setreadonly

function setreadonly(object: table, readonly: boolean): ()

Sets whether object is frozen or read-only.

Parameters

• object - A table or userdata.

• readonly - Whether or not object should be frozen.

Example

local object = {}

table.freeze(object)
print(isreadonly(object)) --> true

setreadonly(object, false)
print(isreadonly(object)) --> false