Re: Using Lua to implement C++ methods.
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- Subject: Re: Using Lua to implement C++ methods.
- From: Noel Frankinet <nfr@...>
- Date: 2006年5月31日 09:05:39 +0200
Hello all,
I'm new to Lua, but I think that it is an excellent scripting language
and would like to use it in combination with C++. I've read a good deal
of http://www.lua.org/pil/ ,
especially "Part IV. The C API", but
apparently due to my lack of experience with Lua, I've not been able to
my problem myself.
The problem is that I have a simple hierarchy (a tree) of C++ objects,
as for example windows that can be found in a GUI system:
(For clarity, I'm just providing pseudo-code, it will probably not compile.)
class Window
{
public:
Window* Find(char* n); // Find a window with name "n" in the
hierarchy tree of this window.
void Draw(); // Draws this window on the screen -
implemented in C++.
void SomeMethod(float f); // Some helper method for demonstration
purposes, also implem. in C++.
void OnMouseClick(); // Some event handler - supposed to be
implemented by a Lua script!
std::string name; // Name of this window, e.g. for
reference in Lua scripts.
int pos[2]; // The position of the top-left corner of
this window.
int size[2]; // The size of this window in pixels.
float back_col[3]; // The background color.
float text_col[3]; // The text / foreground color.
std::string text; // Text to be displayed in the window.
Window* parent; // The parent of this window (may be NULL).
vector<Window*> children; // The sub-windows of this window (e.g.
the buttons in a dialog).
};
Again, you can use Lunar for the OnClick call-back
here is what I do :
---------------------------------------------------------------------------
void LuaMenu::OnDispatch(void *ptr1,void *ptr2,const string & cmd)
{
Gui_dialog *d = (Gui_dialog *)ptr1;
Gui_gadget *g = (Gui_gadget *)ptr2;
lua_State *L = (lua_State *)d->user_info();
//find a way to push dialog and gadget on lua stack
/* push functions and arguments */
lua_getglobal(L, cmd.c_str());
LuaDialog dialog(L,d);
Lunar<LuaDialog>::push(L,&dialog);
LuaGadget gadget(L,g);
Lunar<LuaGadget>::push(L,&gadget);
/* do the call (0 arguments, 0 result) */
if (lua_pcall(L, 2, 0, 0) !=0)
{ char buf[500];
sprintf(buf, "error running function `f': %s",
lua_tostring(L, -1));
MessageBox(NULL,wstr(buf),L"Error",MB_OK);
}
}
-------------------------------------------------------
In the lua world you end up with a dialog and gadget "object" that you
can use "dialog:method"
Maybe it will help
Best wishes
--
Noël Frankinet
Gistek Software SA
http://www.gistek.net