# Closures

## checkcaller

```lua
<boolean> checkcaller()
```

Returns whether the function currently running was called by the executor.

This is useful for metamethod hooks that behave differently when called by the game.

***

## clonefunction

```lua
<function> clonefunction(<function> func)
```

Generates a new closure based on the bytecode of function `func`.

```lua
local function foo()
    print("Hello, world!")
end

local bar = clonefunction(foo)

foo() --> Hello, world!
bar() --> Hello, world!
print(foo == bar) --> false
```

***

## getcallingscript

```lua
<BaseScript> getcallingscript()
```

Returns the script responsible for the currently running function.

***

## hookfunction

```lua
<function> hookfunction(<function> func, <function> hook)
```

Replaces `func` with `hook` internally, where `hook` will be invoked in place of `func` when called.&#x20;

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

If `func` is a Luau function (`islclosure(func) --> true`), the upvalue count of `hook` must be less than or equal to that of `func`. [Lua visibility rules](http://www.lua.org/manual/5.1/manual.html#2.6)

```lua
local function foo()
    print("Hello, world!")
end

local fooRef = hookfunction(foo, function(...)
    print("Hooked!")
end)

foo() --> Hooked!
fooRef() --> Hello, world!
```

***

## iscclosure

```lua
<boolean> iscclosure(<function> func)
```

Returns whether or not `func` is a closure whose source is written in C.

***

## islclosure

```lua
<boolean> islclosure(<function> func)
```

Returns whether or not `func` is a closure whose source is written in Luau.

***

## isexecutorclosure

```lua
<boolean> isexecutorclosure(<function> func)
```

Returns whether or not `func` was created by the executor.

***

## loadstring

```lua
<function?, string?> loadstring(<string> source, <string?> chunkname)
```

Generates a chunk from the given source code. The environment of the returned function is the global environment.

If there are no compilation errors, the chunk is returned by itself; otherwise, it returns `nil` plus the error message.

`chunkname` is used as the chunk name for error messages and debug information.

***

## newcclosure

```lua
<function> newcclosure(<function> func)
```

Returns a C closure that wraps `func`. The result is functionally identical to `func`, but identifies as a C closure.

```lua
local foo = function() return true end
local bar = newcclosure(foo)

print(bar()) --> true
```

***


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