介绍LuaPlus: 好用的Lua For C++扩展(修订)

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作者：沐枫
原文：http://www.cnblogs.com/ly4cn/archive/2005/11/27/285439.html

 

LuaPlus是Lua的C++增强，也就是说，LuaPlus本身就是在Lua的源码上进行增强得来的。用它与C++进行合作，是比较好的一个选择。
LuaPlus目前版本为：LuaPlus for Lua 5.01 Distribution Build 1080 (February 28, 2004)。大家可以到http://luaplus.org/ 站点下载：
源码   (http://wwhiz.com/LuaPlus/LuaPlus50_Build1081.zip)
目标码 (http://wwhiz.com/LuaPlus/LuaPlus50_Build1081_Win32Binaries.zip)

介绍LuaPlus: 好用的Lua For C++扩展     沐枫网志

[由于lua内核升级到5.1，因此，luaplus也同样跟着升级。最新的luaplus可以通过svn获取，地址 svn://svn.luaplus.org/LuaPlus/work51，
同时，luaplus基于5.0的内核仍然在维护更新，也可以通过svn获取，地址 svn://svn.luaplus.org/root/LuaPlus/Dev ]

我将在下面说明，如何使用LuaPlus，以及如何更方便的让LuaPlus与C++的类合作无间。

1. 调用Lua脚本

 

    // 创建Lua解释器：
    LuaStateOwner state; 
    
    // 执行Lua脚本：
    state->DoString("print('Hello World\\n')");
    // 载入Lua脚本文件并执行：
    state->DoFile("C:\\test.lua");
    // 载入编译后的Lua脚本文件并执行：
    state->DoFile("C:\\test.luac");

2. 与Lua脚本互相调用

    // 为Lua脚本设置变量
    state->GetGlobals().SetNumber("myvalue", 123456);
    // 获得Lua变量的值
    int myvalue = state->GetGlobal("myvalue").GetInteger();
    
    // 调用Lua函数
    LuaFunction<int> luaPrint = state->GetGlobal("print");
    luaPrint("Hello World\n");
    
    // 让Lua调用C语言函数
    int add(int a, int b){ return a+b;}
    state->GetGlobals().RegisterDirect("add", add);
    state->DoString("print(add(3,4))");
    
    // 让Lua调用C++类成员函数
    class Test{public: int add(int a, int b){return a+b;}};
    Test test;
    state->GetGlobals().RegisterDirect("add", test, &Test::add);
    state->DoString("print(add(3,4))");

   
3. 在Lua脚本中使用C++类
   
    这个稍微有点小麻烦。不过，我包装了一个LuaPlusHelper.h的文件，它可以很轻松的完成这个工作。它的实现也很简单，大家可以从源码上来获得如何用纯LuaPlus实现同样的功能。
    不过，这里仍然有一个限制没有解决：不能使用虚成员函数。不过考虑到我们仅是在Lua调用一下C++函数，并不是要将C++完美的导入到Lua，这个限制完全可以接受。
    另外，类成员变量不能直接在Lua中访问，可以通过类成员函数来访问（比如SetValue/GetValue之类)。 

// 下面是一个简单的C++类:    
 class Logger
 {
 public:
  void LOGMEMBER(const char* message)
  {
   printf("In member function: %s\n", message);
  }
 
  Logger()
  {
   printf("Constructing(%p)\n", this);
   v = 10;
  }
  virtual ~Logger()
  {
   printf("Destructing(%p)\n", this);
  }
 
  Logger(int n)
  {
   printf(" -- Constructing[%d](%p)\n", n, this);
  }
  Logger(Logger* logger)
  {
   printf(" -- Constructing[%p](%p)\n", logger, this);
   logger->LOGMEMBER(" Call From Constructor\n");
  }
  int SetValue(int val)
  {
   v = val;
  }
  int GetValue()
  {
   return v;
  }
 public:
  int v;
 };

 

    // 导入到Lua脚本：
    LuaClass<Logger>(state)
       .create("Logger") // 定义构造函数 Logger::Logger()
       .create<int>("Logger2")  // 定义构造函数 Logger::Logger(int)
       .create<Logger*>("Logger3") // 定义构造函数 Logger::Logger(Logger*)
       .destroy("Free")  // 定义析构函数 Logger::~Logger()
       .destroy("__gc")  // 定义析构函数 Logger::~Logger()
       .def("lm", &Logger::LOGMEMBER)  // 定义成员函数 Logger::LOGMEMBER(const char*)
       .def("SetValue", &Logger::SetValue)
       .def("GetValue", &Logger::GetValue);

 

    // 在Lua中使用Logger类(1)：
    state->DoString(
        "l = Logger();"  // 调用构造函数 Logger::Logger()
        "l:lm('Hello World 1');"  // 调用成员函数 Logger::LOGMEMBER(const char*)
        "l:Free();"  // 调用析构函数 Logger::~Logger()
        );

 

    // 在Lua中使用Logger类(2)：
    state->DoString(
        "m = Logger2(10);" // 调用构造函数 Logger::Logger(int)
        "m:lm('Hello World 2');"  // 调用成员函数 Logger::LOGMEMBER(const char*)
        "n = Logger3(m);" // 调用构造函数 Logger::Logger(Logger*)
        "n:lm('Hello World 3');"  // 调用成员函数 Logger::LOGMEMBER(const char*)
        "m:SetValue(11);"
        "print(m.GetValue());"
        "m,n = nil, nil;" // m,n 将由Lua的垃极回收来调用析构函数
        );

4. 将一组C函数归类到Lua模块

 

    //同上面一样，我采用LuaPlusHelper.h来简化：
    LuaModule(state, "mymodule")
       .def("add", add)
       .def("add2", test, add);
 
    state->DoString(
        "print(mymodule.add(3,4));"
        "print(mymodule.add2(3,4));"
        );

5. 使用Lua的Table数据类型

    // 在Lua中创建Table
    LuaObject table = state->GetGlobals().CreateTable("mytable");
    table.SetInteger("m", 10);
    table.SetNumber("f", 1.99);
    table.SetString("s", "Hello World");
    table.SetWString("ch", L"你好");
    table.SetString(1, "What");
    
    // 相当于Lua中的：
    // mytable = {m=10, f=1.99, s="Hello World", ch=L"你好", "What"}

  

    // 也可以使用table作为key和value:
    state->GetGlobals().CreateTable("nexttable")
        .SetString(table, "Hello")
        .SetObject("obj", table);
    // 相当于Lua中的：
    // nexttable = {mytable="Hello", obj=mytable}

 

    //获得Table的内容：
    LuaObject t2 = state->GetGlobals("mytable");
    int m = t2.GetByName("m").GetInteger();
    
    LuaObject t3 = state->GetGlobals("nexttable");
    std::string str = t3.GetByObject(t2).GetString();

   
6  遍历Table

 

 LuaStateOwner state;
 state.DoString( "MyTable = { Hi = 5, Hello = 10, Yo = 6 }" );
 
 LuaObject obj = state.GetGlobals()[ "MyTable" ];
 for ( LuaTableIterator it( obj ); it; it.Next() )
 {
     const char* key = it.GetKey().GetString();
     int num = it.GetValue().GetInteger();
 }

篇尾

上面我只是简单的举一些例子来说明LuaPlus以及LuaPlusHelper的使用方法，具体文档请参见LuaPlus。

需要下载LuaPlusHelper，请点这里：
http://files.cnblogs.com/ly4cn/LuaPlusHelper.rar

 

#pragma once#include "luaplus.h"#include <string>class LuaConvert{public:LuaConvert(LuaObject& obj): refobj(obj){}operator int(){return refobj.GetInteger();}operator float(){return refobj.GetFloat();}operator double(){return refobj.GetDouble();}operator const char* (){return refobj.GetString();}operator const wchar_t* (){return refobj.GetWString();}operator std::string(){return std::string(refobj.GetString());}operator std::wstring(){return std::wstring(refobj.GetWString());}operator void* (){return refobj.GetUserData();}template<typename T>operator T* (){return (T*)refobj.GetUserData();}template<typename R>operator LuaFunction<R> (){return LuaFunction<R>(refobj);}private:LuaObject refobj;};template<typename Object>class LuaConstructor{private:staticint ConstructorHelper(LuaState* state, Object* pObj){std::string metaname("MetaClass_");metaname += typeid(Object).raw_name();LuaObject obj = state->BoxPointer(pObj);obj.SetMetaTable(state->GetGlobal(metaname.c_str()));obj.PushStack();return 1;}public:staticint Constructor(LuaState* state){return ConstructorHelper(state, new Object());}template<typename A1>staticint Constructor(LuaState* state){LuaConvert a1 = LuaObject(state, 1);return ConstructorHelper(state, new Object((A1)a1) );}template<typename A1, typename A2>staticint Constructor(LuaState* state){LuaConvert a1 = LuaObject(state, 1);LuaConvert a2 = LuaObject(state, 2);return ConstructorHelper(state, new Object((A1)a1, (A2)a2) );}template<typename A1, typename A2, typename A3>staticint Constructor(LuaState* state){LuaConvert a1 = LuaObject(state, 1);LuaConvert a2 = LuaObject(state, 2);LuaConvert a3 = LuaObject(state, 3);return ConstructorHelper(state, new Object((A1)a1, (A2)a2, (A3)a3) );}template<typename A1, typename A2, typename A3, typename A4>staticint Constructor(LuaState* state){LuaConvert a1 = LuaObject(state, 1);LuaConvert a2 = LuaObject(state, 2);LuaConvert a3 = LuaObject(state, 3);LuaConvert a4 = LuaObject(state, 4);return ConstructorHelper(state, new Object((A1)a1, (A2)a2, (A3)a3, (A4)a4) );}template<typename A1, typename A2, typename A3, typename A4, typename A5>staticint Constructor(LuaState* state){LuaConvert a1 = LuaObject(state, 1);LuaConvert a2 = LuaObject(state, 2);LuaConvert a3 = LuaObject(state, 3);LuaConvert a4 = LuaObject(state, 4);LuaConvert a5 = LuaObject(state, 5);return ConstructorHelper(state, new Object((A1)a1, (A2)a2, (A3)a3, (A4)a4, (A5)a5) );}static int Destructor(LuaState* state){LuaObject o(state, 1);delete (Object*)state->UnBoxPointer(1);LuaObject meta = state->GetGlobal("MetaClass_Nil");if(meta.IsNil()){meta = state->GetGlobals().CreateTable("MetaClass_Nil");}o.SetMetaTable(meta);return 0;}};template<typename Object>class LuaClass{public:LuaClass(LuaState* state){luaGlobals = state->GetGlobals();std::string metaname("MetaClass_");metaname += typeid(Object).raw_name();metaTableObj = luaGlobals.CreateTable(metaname.c_str());metaTableObj.SetObject("__index", metaTableObj);//metaTableObj.Register("__gc", &Destructor);//metaTableObj.Register("Free", &Destructor);}template<typename Func>inline LuaClass& def(const char* name, Func func){metaTableObj.RegisterObjectDirect(name, (Object*) 0, func);return *this;}inline LuaClass& create(const char* name){luaGlobals.Register(name, LuaConstructor<Object>::Constructor);return *this;}template<typename A1>inline LuaClass& create(const char* name){luaGlobals.Register(name, LuaConstructor<Object>::Constructor<A1>);return *this;}template<typename A1, typename A2>inline LuaClass& create(const char* name){luaGlobals.Register(name, LuaConstructor<Object>::Constructor<A1, A2>);return *this;}template<typename A1, typename A2, typename A3>inline LuaClass& create(const char* name){luaGlobals.Register(name, LuaConstructor<Object>::Constructor<A1, A2, A3>);return *this;}template<typename A1, typename A2, typename A3, typename A4>inline LuaClass& create(const char* name){luaGlobals.Register(name, LuaConstructor<Object>::Constructor<A1, A2, A3, A4>);return *this;}template<typename A1, typename A2, typename A3, typename A4, typename A5>inline LuaClass& create(const char* name){luaGlobals.Register(name, LuaConstructor<Object>::Constructor<A1, A2, A3, A4, A5>);return *this;}inline LuaClass& destroy(const char* name){metaTableObj.Register(name, LuaConstructor<Object>::Destructor);return *this;}private:LuaObject metaTableObj;LuaObject luaGlobals;};class LuaModule{public:LuaModule(LuaState* state){luaModuleObj = state->GetGlobals();}LuaModule(LuaState* state, const char* name){luaModuleObj = state->GetGlobals().CreateTable(name);}template<typename Func>inline LuaModule& def(const char* name, Func func){luaModuleObj.RegisterDirect(name, func);return *this;}template<typename Object, typename Func>inline LuaModule& def(const char* name, Object& o, Func func){luaModuleObj.RegisterDirect(name, o, func);return *this;}private:LuaObject luaModuleObj;};

测试程序(VC7.1)：
http://files.cnblogs.com/ly4cn/LuaPlusTest.rar

 

// LuaCppWrapper.cpp : 定义控制台应用程序的入口点。//#include "stdafx.h"#include "LuaPlusHelper.h"void LOG(const char* message){printf("In global function: %s\n", message);}class Logger{public:void LOGMEMBER(const char* message){printf("In member function: %s\n", message);}virtual void LOGVIRTUAL(const char* message){printf("In virtual member function: %s\n", message);}Logger(){printf("Constructing(%p)...\n", this);v = 10;}virtual ~Logger(){printf("Destructing(%p)...\n", this);}Logger(int n){printf(" -- Constructing[%d](%p)...\n", n, this);}Logger(Logger* logger){printf(" -- Constructing[%p](%p)...\n", logger, this);logger->LOGMEMBER("-- 0000---0000\n");}public:int v;};void LOG2(const char* message, LuaObject xlogger){Logger* logger = (Logger*)xlogger.GetUserData();printf("In global function: %s\n", message);printf("---%d\n", logger->v);logger->LOGMEMBER(message);}int _tmain(int argc, _TCHAR* argv[]){{LuaStateOwner state; Logger logger;LuaModule(state).def("LOG", LOG).def("LOGMEMBER", logger, &Logger::LOGMEMBER).def("LOGVIRTUAL", logger, &Logger::LOGVIRTUAL).def("LOG2", LOG2);LuaClass<Logger>(state).create("Logger").create<int>("Logger2").create<Logger*>("Logger3").destroy("Free").destroy("__gc").def("lm", &Logger::LOGMEMBER).def("lv", &Logger::LOGVIRTUAL);state->GetGlobals().SetNumber("a", 123456);int a = state->GetGlobal("a").GetInteger();printf(" a = %d\n", a);state->DoString("LOG('Hello')");state->DoString("LOGMEMBER('Hello')");state->DoString("LOGVIRTUAL('Hello')");state->DoString("print('=========');""print(Logger, _G['MetaClass_.?AVLogger@@']);""l = Logger();");state->DoString("print(l);""print(l.lv);""print(l.lm);");state->DoString("print('=========');");state->DoString("l:lm('Hhhhh');");//state->DoString("l:lv('Eeeee');"); //--虚函数不能用！！！state->DoString("--l:Free();l=nil;");state->DoString("print('=========');");state->DoString("LOG2('SSSS', l)");state->DoString("print('=========');");state->DoString("k = Logger2(10);k:lm('World2');k:Free();");state->DoString("print('=========', l);");state->DoString("h = Logger3(l);h:lm('World!!!!!!!!!');");LuaFunction<int> l = state->GetGlobal("LOG");l("DDDDDD");}system("Pause");return 0;}