Interpreter Features Question

Hello guys!
Here I come with new problem,...

I'm stuck, I'm stuck, I'm stuck, Google can't help me anymore. *sob*

Btw, I have questions about dynamic function for interpreter that can interact with DLL.

1. How to call loaded DLL function with n parameter?

Code:

---

import long MessageBox as "MessageBoxA" (HWND hWnd, char *message ...) from "user32.dll";

MessageBox(0, "Hello world", "Test", 16);

---

Should I use assembly code for this?

Code:

---

push 0
push "Hello world"
push "Test"
push 16
call MessageBoxA

---

2. I need to make an interpreter that supports callback from DLL.
This means the interpreter should generate function pointers with n argument and pass it to the DLL function. For example: SetWindowsHookEx, SetWindowLong.

Code:

---

HRESULT OnActivate(HWND hWnd, ...)
{
  ...
}

SetWindowLong(frmMain.handle, GWL_WNDPROC, @OnActivate);

---

I absolutely have no idea on this one...

Please, if anyone have any reference for interpreter thing or dynamic function pointers... It might be help.

Thanks in advance.