lua_createtable(L, 0, 3); 创建大小为3的table

lua_pushcfunction(L, lcopy); 将lcopy压栈

lua_setfield(L, -2, "copy");

{
	copy = lcopy,
}

====================================================================

lua_createtable(L, 0, 2); 创建大小为2的table

lua_pushcfunction(L, ldeletewriter),
lua_setfield(L, -2, "__gc");

lua_pushcfunction(L, lupdate),
lua_setfield(L, -2, "__call");

table = {
	__gc = ldeletewriter,
	__call = lupdate,
}

luaL_Reg writer[] = {
	{ "new", lnewwriter },
	{ NULL, NULL },
};
luaL_setfuncs(L, writer, 1);
将 writer 压入栈顶，并将table作为上值

====================================================================

lua_createtable(L, 0, 2);
lua_pushcfunction(L, ldeletereader),
lua_setfield(L, -2, "__gc");
lua_pushcfunction(L, lread),
lua_setfield(L, -2, "__call");

table = {
	__gc = ldeletereader,
	__call = lread,
}

luaL_Reg reader[] = {
	{ "newcopy", lnewreader },
	{ NULL, NULL },
};
luaL_setfuncs(L, reader, 1);
将 reader 压入栈顶，并将table作为上值

====================================================================

{
	copy = lcopy,
	writer = ...,
	reader = ...,
}

====================================================================

	luaL_Reg m[] = {
		{ "pop", lpop },
		{ "push", lpush },
		{ "size", lsize },
		{ NULL, NULL },
	};
	luaL_newmetatable(L, "dangge.deque"); 创建一个meta表并压栈
	lua_pushvalue(L, -1); 复制一个meta表
	lua_setfield(L, -2, "__index"); meta = {__index = meta}
	luaL_setfuncs(L, m, 0); meta = {pop = lpop, push = lpush, size = lsize}