在C中存储对Lua值的引用，该怎么做呢？
在C中存储对Lua值的引用，该怎么做呢？
提问于 2012-08-19 11:14:55
例如，假设我有一个键处理接口，在C++中定义为：
class KeyBoardHandler
{
public:
virtual onKeyPressed(const KeyEventArgs& e);
virtual onKeyReleased(const KeyEventArgs& e);
}现在，我想将其扩展到Lua，以允许Lua利用并在脚本中注册KeyboardHandler。
这是到目前为止的原型。
class ScriptKeyboardHandler : public KeyboardHandler
{
public:
... previous methods omitted
static void createFromScript(lua_State* L);
bool createCppData();
private:
ScriptKeyBoardHandler(lua_State* L);
int mSelf;
int mKeyPressFunc;
int mKeyReleaseFunc;
lua_State* mpLuaState;
}现在，我知道实现会是这样的：
ScriptKeyboardHandler::ScriptKeyboardHandler(lua_State* L) :
mpState(L)
{ }
ScriptKeyboardHandler::onKeyPressed(...) {
// check if mKeyPressFunc is a function
// call it, passing in mself, and the event args as params
}
// On Key Release omitted because being similar to the key pressed
ScriptKeyboardHandler::createFromScript(lua_State* L)
{
auto scriptKeyboardHandler = new ScriptKeyboardHandler(L);
if (scriptKeyboardHandler->createCppData())
{
// set the light user data and return a reference to ourself (mSelf)
}
}
ScriptKeyboardHandler::createCppData()
{
// get the constructor data (second param) and find the keyPressed and keyReleased function, store those for later usage
// any other data within the constructor data will apply to object
}
-- Syntax of the lua code
MyScriptHandler = { }
MyScriptHandler.__index = MyScriptHandler
MyScriptHandler.onKeyPress = function(self, args)
end
handler = createScriptHandler(handler, MyScriptHandler)
registerKeyHandler(handler)我只是不知道当函数作为参数传递到表中时如何查找它们。
我这样做对吗？我希望我是，因为tolua不容易支持虚拟类，不能从脚本中派生出来，所以这一直是一个痛苦的问题。
我不担心其他函数，只是我如何从C代码中找到这些变量(按键函数等
回答 1
Stack Overflow用户
回答已采纳
发布于 2012-08-19 11:36:59
下面是我的onKeyPressed实现的大致情况。
void ScriptKeyboardHandler::onKeyPressed()
{
//Get the table corresponding to this object from the C registry
lua_pushlightuserdata(mpLuaState, this);
lua_gettable(mpLuaState,LUA_REGISTRYINDEX);
//Now get the function to call from the object
lua_pushstring(mpLuaState,"onKeyPress");
lua_gettable(mpLuaState,-2);
//Now call the function
lua_pushvalue(mpLuaState, -2 ); // Duplicate the self table as first argument
//TODO: Add the other arguments
lua_pcall(mpLuaState, 1, 0, 0 ); // TODO: You'll need some error checking here and change the 1 to represent the number of args.
lua_pop(mpLuaState,1); //Clean up the stack
}但是，您还需要更新构造函数以将表示处理程序的lua对象存储到注册表中。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/12023943
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