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介绍LuaPlus: 好用的Lua For C++扩展(修订)

本文版权归 博客沐枫 所有,转载请按如下方式详细标明原创作者及出处,以示尊重!!
 
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

{publicint 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 " , 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:

	static	int 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:

	static	int Constructor(LuaState* state)
	{
		return ConstructorHelper(state,new Object());
	}

	template<typename A1>
		static	int Constructor(LuaState* state)
	{
		LuaConvert a1 = LuaObject(state,1);
		return ConstructorHelper(state,new Object((A1)a1) );
	}

	template<typename A1,typename A2>
		static	int 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>
		static	int Constructor(LuaState* state)
	{
		LuaConvert a1 = LuaObject(state,2);
		LuaConvert a3 = LuaObject(state,3);
		return ConstructorHelper(state,(A2)a2,(A3)a3) );
	}

	template<typename A1,typename A3,typename A4>
		static	int Constructor(LuaState* state)
	{
		LuaConvert a1 = LuaObject(state,3);
		LuaConvert a4 = LuaObject(state,4);
		return ConstructorHelper(state,(A3)a3,(A4)a4) );
	}

	template<typename A1,typename A4,typename A5>
		static	int Constructor(LuaState* state)
	{
		LuaConvert a1 = LuaObject(state,4);
		LuaConvert a5 = LuaObject(state,5);
		return ConstructorHelper(state,(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 A3>
		inline LuaClass& create(const char* name)
	{
		luaGlobals.Register(name,A2,A3>);
		return *this;
	}
	template<typename A1,typename A4>
		inline LuaClass& create(const char* name)
	{
		luaGlobals.Register(name,A3,A4>);
		return *this;
	}
	template<typename A1,typename A5>
		inline LuaClass& create(const char* name)
	{
		luaGlobals.Register(name,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,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::LOGMEMBER)
			.def("LOGVIRTUAL",&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;
}

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