debug.getupvalue
Reads upvalues. Globals: getupvalue / getupvalues.
Syntax
debug.getupvalue(func: any, index: number) -> anyParameters
| Parameter | Type | Description |
|---|---|---|
func | any | The func value used by the call. |
index | number | A one-based index. |
Returns
| Type | Description |
|---|---|
any | The value produced by the call. |
Description
debug.getupvalue is part of the Debug library. The debug library exposes the internals of the active Luau state, including protos, constants, upvalues and stack frames.
The call is read-only: it resolves the current value when invoked and does not change the underlying state.
The aliases debug.getupvalues(func) resolve to the same implementation.
Example
local value = 10
local function f() return value end
print(debug.getupvalue(f, 1))
print(#debug.getupvalues(f))Notes
- Aliases:
debug.getupvalues(func). - Writing protos, constants or upvalues can corrupt a running function; test changes carefully.