__call and userdata

[Graham Wakefield <lists@...>]

Hi all,

I'm having trouble using __call in a metatable for userdata; is this  
supported?

Here's a rough sketch:

print(Noise)
table.foreach(Noise, print)
noise = Noise()

output:

table: 0x7162b8
__gc	function: 0x716318
__call	function: 0xffd00
__index	table: 0x7162b8
new	function: 0x7162e0
error: attempt to call global 'Noise' (a table value)

The C++ code called to load the Noise metatable:

int Noise :: init_metatable(lua_State * L)
{
	luaL_newmetatable(L, "Noise");	// create a new class metatable
	
	// mt.__index = mt
	lua_pushstring(L, "__index");
	lua_pushvalue(L, -2);	
	lua_settable(L, -3);
	
	// install constructor:
	lua_pushstring(L, "new");
	lua_pushcfunction(L, Noise::__new);
	lua_settable(L, -3);
	
	lua_pushstring(L, "__call");
	lua_pushcfunction(L, Noise::__new);
	lua_settable(L, -3);
	
	// install default destructor:
	lua_pushstring(L, "__gc");	
	lua_pushcfunction(L, Noise::__gc);
	lua_settable(L, -3);
	
	// make metatable available globally:
	lua_pushvalue(L, -1);
	lua_setglobal(L, "Noise");
	
	return 1;	// leaves the metatable on the stack
}