hookfunction

Replaces target with hook and returns the original target function, so the original behavior is still callable.

hookfunction(target: function, hook: function): function

Once hooked, every call to target runs hook instead.

Most commonly used to intercept a function (i.e. print), or wrap its calls without losing access to the original.

Closure types may differ between target and hook - Luau-to-Luau, C-to-C, or any cross-direction.

newcclosure-wrapped targets work, and the hook can carry a different upvalue count from the target.

Parameters

Both arguments are required, otherwise - errors.

Parameter	Type	Description
target	function	The function to replace. Lclosure, cclosure, or newcclosure-wrapped - all accepted.
hook	function	The function that runs in target’s place.

Returns

function - original target function, before the hook was applied. Use it from inside hook to trigger pre-hook behavior - return original(...).

Handles don’t go stale on re-hook. Hook target a second time and the earlier handle still calls the body that was live when you first got it back.

Aliases

• hookfunc
• replaceclosure

Example

You want to mirror every call to a game function into your own pipeline - logs, counters, side-channel events. Hook the function so your code fires first, then defer to the original.

Example 1

<<<<<<< HEAD
local oldPrint = hookfunction(print, function(...)
    return oldPrint(...)
end)
=======
-- hookfunction(target: function, hook: function): function
>>>>>>> 50e30f53759b0538759af25c9b271514aa2c9290

Always call the returned handle from inside your hook, not the target’s original name. Calling StockUpdated(...) inside the hook re-enters the hook and recurses until the script crashes. Old(...) skips the hook and calls the pre-hook body.