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lua 中pairs �?ipairs区别

Let me see see — Fri, 16 Dec 2011 00:43:00 GMT

标准库提供了集中�q�代器，包括�q�代文�g每行�?io.lines)�Q��P代table元素�?pairs)�Q��P代数�l�元素的(ipairs)�Q��P代字�W�串中单词的

(string.gmatch)�{�等。LUA手册中对与pairs,ipairs解释如下�Q?br />

`ipairs (t)`

Returns three values: an iterator function, the table t, and 0, so that the construction

for i,v in ipairs(t) do body end

will iterate over the pairs (1,t[1]), (2,t[2]), ···, up to the first integer key absent from the table.

`pairs (t)`

Returns three values: the next function, the table t, and nil, so that the construction

for k,v in pairs(t) do body end

will iterate over all key–value pairs of table t.

See function next for the caveats of modifying the table during its traversal.

�q�样��可以看�? ipairs以及pairs 的不同�?/p>

pairs可以遍历表中所有的key�Q��ƈ且除了�P代器本��n以及遍历表本�w�还可以�q�回nil;

但是ipairs则不能返回nil,只能�q�回数字0�Q�如果遇到nil则退出。它只能遍历到表中出现的�W�一个不是整数的key

下面举个例子吧！

eg�Q?/p>

local tabFiles = {

[3] = "test2",

[6] = "test3",

[4] = "test1"

}

for k, v in ipairs(tabFiles) do

print(k, v)

end

猜测它的输出�l�果是什么呢�Q?/p>

�Ҏ��刚才的分析，它在 ipairs(tabFiles) 遍历中，当key=1时候value��是nil�Q�所以直接蟩出��@环不输出��M��倹{�?/p>

>lua -e "io.stdout:setvbuf 'no'" "Test.lua"

>Exit code: 0

那么�Q�如果是

for k, v in pairs(tabFiles) do

print(k, v)

end

则会输出所�?�Q?/div>

>lua -e "io.stdout:setvbuf 'no'" "Test.lua"

3 test2

6 test3

4 test1

>Exit code: 0

现在改变一下表内容�Q?/div>

local tabFiles = {

[1] = "test1",

[6] = "test2",

[4] = "test3"

}

for k, v in ipairs(tabFiles) do

print(k, v)

end

现在的输出结果显而易见就是key=1时的value值test1

>lua -e "io.stdout:setvbuf 'no'" "Test.lua"

1 test1

>Exit code: 0

--[�C�Z��1.]--
local tt =
{
    [1] = "test3",
    [4] = "test4",
    [5] = "test5"
}

for i,v in pairs(tt) do        -- 输出 "test4" "test3" "test5"
    print( tt[i] )
end

for i,v in ipairs(tt) do    -- 输出 "test3" k=2时断开
    print( tt[i] )
end

-- [[�C�Z��2.]] --
tbl = {"alpha", "beta", [3] = "uno", ["two"] = "dos"}

for i,v in ipairs(tbl) do    --输出前三�?br />    print( tbl[i] )
end

for i,v in pairs(tbl) do    --全部输出
    print( tbl[i] )
end

Let me see see 2011-12-16 08:43 发表评论

lua5.1 �~�译+实例(�?

Let me see see — Tue, 28 Jun 2011 02:06:00 GMT

官方的Wiki:http://lua-users.org/wiki/TutorialExamples
以下是关于vs2005中��用lua

以下是我在vs2005中编译方法：

1:打开vs命��o行工兗��? 工具->visual studio 2005 command prompt

2:到lua-5.1的目录也��是etc的上一�U�目�? �Q�cd/d d:\lua-5.1

3:执行�Q�etc\luavs.bat(注意�Q�这里是\�Q�不�?)

4:然后lua51.dll �Q�lua51.lib�Q�lua.exe��q��成在src路径下了~�Q�注意因为是lua5.1的所以没有luac.exe,以前的版本有�Q?/span>

因�ؓ在vs2005中lua是外来的�Q�所以要让vs2005能找到lua的头文�g和库文�g�Q?/span>lua5.1中只有一个lua51.lib�Q�，在vs中包�?/span>

于是:工具->选项->��目和解��x��?>vc++ 目录双��选择包含文�g把src的�\径包含进来（关于头文件的�Q?/span>

�q�有库文件同意的操作�Q�不�q�这里就是后来一直出错的点，�q�里�q�种方式包含的库文�g是包含不�q�来的，后面讲到的一�U�方法可正确包含

头文件和库文仉��包含�q�来后就可以在c++中��用lua�?/span>

看一个实例如下：

#include

extern "C"

{

#include "lua.h"

#include "lualib.h"

#include "lauxlib.h"

}//在工具中包含文�g的那个~~

/* Lua解释器指�?*/

lua_State * L;

#pragma comment(lib,"lua51.lib")//包含库文件~~在工具里包含不进来，上面的包含不�q�来的处理办法是�Q?/span>

//把lua51.dll 拷到��目的dubug目录下，把lua51.lib拷到��目目录的项目名的文件夹�?/span>

int main ()

{

/* 初始化Lua */

L = lua_open();

/* 载入Lua基本�?*/

luaL_openlibs(L);

/* �q�行脚本 ,注意路径*/

luaL_dofile(L, "d:\\test.lua");

/* 清除Lua */

lua_close(L);

//printf( "Press enter to exit…" );

//getchar();

return 0;

}

上面是c++的一个空工程

下面是test.lua的代码：是一个石头剪子布的小的游戏实�?

代码如下�Q?/span>

---[[

math.randomseed(os.time()) --[[为随机数产生器生成一个种�?-]]

user_score = 0

comp_score = 0 -- 全局变量存分�?/span>

lookup = {}; --输赢对照�?/span>

lookup["rock"]={rock = "draw",paper = "lose",scissors ="win"}

lookup["paper"]={rock = "win",paper = "draw",scissors = "lose"}

lookup["scissors"]={rock = "lose",paper = "win",scissors = "draw"}

function GetAiMove() --Ai的函�?/span>

local int_to_string = {"rock","paper","scissors"} --局部一个table�Q�对照用

return int_to_string[math.random(3)]

end

function EvaluateTheGuess(user_guess,comp_guess) -- 计算�l�果的函�?/span>

if(lookup[user_guess][comp_guess]=="win") then

print ("user win the game")

--print()

user_score=user_score+1 --��错�?~已改

elseif (lookup[user_guess][comp_guess]=="lose") then

print ("user lose the game")

--print()

comp_score=comp_score+1

else

print ("draw!")

--print()

end

--下面开�?/span>

print ("game begin:enter q to guit game")

--print() --换行�Q?/span>

loop = true

while loop==true do

--print()

print("user: "..user_score.." comp: "..comp_score)

print()

print("p--�? r--招_�� s--�?)

print("误��入：")

--io.open()

user_guess =io.stdin:read '*l' --出错的地�?�q�里是l不是1

--user_guess = "r"

print()

local letter_to_string = {r="rock",s="scissors",p="paper"} --亦是局部的一个table 对照用的

if(user_guess == "q") then

loop = false

elseif(user_guess == "r") or (user_guess == "s") or(user_guess =="p") then

comp_guess=GetAiMove()

EvaluateTheGuess(letter_to_string[user_guess],comp_guess)

else

print ("invalid input,try again")

end

--]]

Let me see see 2011-06-28 10:06 发表评论

LUA脚本学习

Let me see see — Mon, 06 Sep 2010 10:18:00 GMT

从lua调用C++函数和对�?br>    利用LuaPlus可以方便的从C++中调用lua脚本�Q�翻�q�也一栗��通过注册函数或类对象�Q�lua便可以访问C++�?

一、C风格函数注册
    Lua提供了C风格的回调函数注册，该函数原型如下：
    int Callback(LuaState* state);

    无论是全局函数、类非虚函数、类虚函敎ͼ�只要�W�合上面的原型，都可以向Lua注册。我们以全局函数��Z��Q�下面是我们提供的一个回调函数CStyleAddFunc�Q?/p>

int CStyleAddFunc(LuaState * state)
{    LuaStack args(state);
      if( args[1].IsNumber() && args[2].IsNumber() )
      {    state->PushNumber(args[1].GetInteger() + args[2].GetInteger());
           return 1;
      }
      return 0;
}

在回调函��C��Q�我们通过栈来讉K��参数�Q�栈中可以存贮多个参敎ͼ�LuaStack args(state);语句获取栈对象供后箋讉K��?nbsp; 接下来判断参数是否是数字�Q�如果两个参数都是数字，那么�q�行加操作，��结果压入栈中，��压入栈中的数据的个数返回。注意，�q�回��g��表压入栈中的元素的个敎ͼ�而不是某�U�计��结果或其它意义的返回倹{��通过改变�q�回值来查看�E�序的输出，�q�样可以对返回值的含义有个感性的了解�?nbsp; 要注册回到只需调用Register函数卛_��Q�这在第一��中已经用到。下面是��试函数�Q?/p>

void TestCFunctionCallBack()
{
   LuaStateOwner state;      //"print" need this
   state->OpenLibs();      //register my function CStyleAddFunc to Add
   state->GetGlobals().Register("Add", CStyleAddFunc);      //call my function and print the result
   state->DoString("ret = Add(1,5);print(ret)");
}

   state->DoString("ret = Add(1,5); print(ret)");该句用来从执行Lua命��o丌Ӏ�我们先调用Add�q�将�l�果赋值给ret变量�Q�然后打印ret的倹{�?main函数如下�Q?

int _tmain(int argc, _TCHAR* argv[])
{
   TestCFunctionCallBack();
   return 0;
}

�~�译�q�行�Q�一切OK�?nbsp; 我们也可以从Lua脚本文�g中调用注册的回调函数�Q�第一��中有演�C��?nbsp; 要注册类的成员函敎ͼ�则需要调用Register的另一�U��Ş式Register( const char* funcName, const Callee& callee, int (Callee::*func)(LuaState*), int nupvalues = 0 );�Q�提供类实例指针和函数即可完成注册。下面是�C�Z��代码�Q?/p>

class CTestCallBack
{
public:
   int NonVirtualFunc(LuaState *state)
   {
    LuaStack args(state);
    printf("In non-virtual member function. no msg. ");
    return 0;
   }

   int virtual VirtualFunc(LuaState *state)
   {
    LuaStack args(state);
    printf("In virtual member function.msg=%s ", args[1].GetString());
    return 0;
   }
};

void TestClassMemberFuncReg()
{
   LuaStateOwner state;      //"print" need this
   state->OpenLibs();
   LuaObject globalobj = state->GetGlobals();
   CTestCallBack tcb;
   globalobj.Register("MemberFunc", tcb, &CTestCallBack::NonVirtualFunc);
   state->DoString("MemberFunc()");
   globalobj.Register("VirMemberFunc", tcb, &CTestCallBack::VirtualFunc);
   state->DoString("VirMemberFunc('Hi,myboy')");
}

修改一下main函数�Q�将TestClassMemberFuncReg()加进��d��可以看效果了�?/p>

二、�Q意�Ş式C++函数注册
LuaPlus提供�?RegisterDirect() 来直接注册�Q意�Ş式的函数�Q�这��h��为直接，不必受限于上�q�的函数原型�Q��用�v来很方便。同��h��函数像Register一��P��可以注册�cȝ��成员函数�Q�也需要显�C�指定this指针�Q�。下面是代码:

float Add(float num1, float num2)
{
return num1 + num2;
}

class CForRegDirect
{
public:
int Sum(int a, int b, int c)
{
     return a+b+c;
}      //const is necessary
virtual void SeeMessage(const char *msg)
{
     printf("msg=%s ", msg);
}
};

void TestRegisterDirect()
{
LuaStateOwner state;
state->OpenLibs();
LuaObject gobj = state->GetGlobals();        //register global function directly
gobj.RegisterDirect("Add", Add);
state->DoString("print(Add(1.5, 2.3))");      //register memberfunction
CForRegDirect forobj;
gobj.RegisterDirect("MemberSum", forobj, CForRegDirect::Sum);
state->DoString("print(MemberSum(1,2,7))");
gobj.RegisterDirect("VirCMsg", forobj, CForRegDirect::SeeMessage);
state->DoString("print(VirCMsg('haha,Do you see me?'))");
}

三、注册函子对�?br> 上面两节的方式可以实现简单的回调注册�Q�注册类的成员函数时需要显式提供类指针�Q�不适合用于映射C++中的�cȝ��构�?nbsp; RegisterObjectFunctor()和元表（metatable�Q�结合，提供了一�U�新的方法。我们不需要在注册函数时显式的提供this指针�Q�作为替代，this指针可以从调用者的userdata或__object成员获取�?nbsp; 元表�Q�metatable�Q�是一个普通的表对象，它定义了一些可以被重写的操作，如add�Q�sub�Q�mul�Q�index�Q�call�{�，�q�些操作�?__"开��_��如__add�Q�__index�{�。加入你重写了__add�Q�那么在执行add操作时就会调用你自己定义的__add操作。这�U�特性可以用来模拟C++中的�c�d��象，注册函子对象正是利用了这�U�特性来实现的�?nbsp; 下面我们��一个C++�c�L��到Lua中。类代码如下�Q?/p>

class CMultiObject
{
public:
   CMultiObject(int num) :m_num(num)
   {     }

   int Print(LuaState* state)
   {
    printf("%d ", m_num);
    return 0;
   }
protected:
   int m_num;

};
void TestRegObjectDispatchFunctor()
{
   LuaStateOwner state;
   state->OpenLibs();      //create metaTable

   LuaObject metaTableObj = state->GetGlobals().CreateTable("MultiObjectMetaTable");
   metaTableObj.SetObject("__index", metaTableObj);     //register functor for multiobject
   metaTableObj.RegisterObjectFunctor("Print", CMultiObject::Print);      //get a instances of CMultiObject

   CMultiObject obj1(10);     //"clone" a object in lua, the lua object(here is table) has obj1's data
   LuaObject obj1Obj = state->BoxPointer(&obj1);     //set lua object's metatable to MetaTableObj
   obj1Obj.SetMetaTable(metaTableObj);     //put lua object to Global scope, thus it can be accessed later.
   state->GetGlobals().SetObject("obj1", obj1Obj);

   CMultiObject obj2(20);
   LuaObject obj2Obj = state->BoxPointer(&obj2);
   obj2Obj.SetMetaTable(metaTableObj);
   state->GetGlobals().SetObject("obj2", obj2Obj);      //now call Print and Print2
   state->DoString("obj1:Print();");
   state->DoString("obj2:Print();");
}

    首先我们需要生成一个元表（metatable�Q�，��C++�cȝ��成员函数注册到该元表中。然后依据CMultiObject的实例生成lua中与其对应的对象�Q�也是表�Q�，��该对象的metatable�Q�也卌��表的__object成员�Q�设�|��ؓ之前产生的元表。最后将新生成的lua对象攄��到全局作用域中�Q�这样后面就可以直接引用�q�些对象�?nbsp;    我们可以做这��L��q�似理解�Q�每个实例的数据元素存放在与已对应的lua table中，而类的成员函数则存放在metatable中（函子对象�Q�。当调用obj1obj:Print()�Ӟ��会先扑ֈ�其metatable�Q�然后在metatable中找Print()函数�?nbsp;    �q�样便实��C��c�M��C++中的�cȝ��构。每个实例有自己的数据，而所有实例共享一份方法列表�?/span>         另外一�U�方式是利用表的userdata来实玎ͼ�需要先创徏一个lua表对象，然后��C++对象obj1讄��表的userdata�Q�也是设�|�其__object成员�Q�，再将该表对象的metatable讄��为我们之前创建的元表。最后就可以用表明来调用Print函数。代码如下：

LuaObject table1Obj = state->GetGlobals().CreateTable("table1");
table1Obj.SetLightUserData("__object", &obj1);
table1Obj.SetMetaTable(metaTableObj);
LuaObject table2Obj = state->GetGlobals().CreateTable("table2");
table2Obj.SetLightUserData("__object", &obj2);
table2Obj.SetMetaTable(metaTableObj);
state->DoString("table1:Print()");
state->DoString("table2:Print()");

注册函子对象�Q�RegisterObjectFunctor�Q�这�U�方式的限制在于�Q�要注册的函数必��ȝ��合原型（int Callback(LuaState* state);�Q�。�ؓ了打破这�U�限�Ӟ��LuaPlus提供了另外一�U�方式�?br>


四、直接注册函子对�?/p>

    直接注册函子对象�Q�RegisterObjectDirect�Q�和RegisterDirect�c�M��Q�不考虑函数原型�Q�可以直接向元表注册��L��形式的函数�?nbsp;    为CMultiObject��d��新的成员函数�Q?br>
void Print2(int num)
{
   printf("%d %d\n", m_num, num);
}

调用RegisterObjectDirect�Ҏ��Q?
metaTableObj.RegisterObjectDirect("Print2", (CMultiObject*)0, &CMultiObject::Print2);

�W�二个参�?CMultiObject*)0有点奇怪，�q�是模板参数的需要�?

最后：
state->DoString("obj1:Print2(5)");
state->DoString("obj2:Print2(15)");
state->DoString("table1:Print2(5)");
state->DoString("table2:Print2(15)");

五、注销回调

    注销回调是�g��单的事情�Q�调用SetNil("yourCallBack")卛_��Q�如�Q?
gobj.SetNil("Add");
metaTableObj.SetNil("Print2");

好了�Q�迄今�ؓ止最长的一��，看着像是LuaPlus文档的翻译（�Q�）�Q�不�q�还是加入了一些自��q��理解。文档我看了下，琢磨了半天才明白。希望能快点��LuaPlus用�v来�?
资料�Q?nbsp;    �Q?�Q�Lua5.1参考手�?nbsp;    �Q?�Q�Lua入门wiki     �Q?�Q�LuaPlus.html�Q�源码包中带的�?br>
转蝲�?a >http://hi.baidu.com/li9chuan/blog/item/e65e1d6dc0bd79f642169461.html

参考：http://gpwiki.org/index.php/Scripting_with_LuaPlus_and_Cpp ��单的LUA脚本�~�写
            http://wwhiz.com/LuaPlus/LuaPlus.html
            http://m.shnenglu.com/iwangchuchu/default.html?page=2

------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
引擎中的��单应用：

void CAICharacterCore::LoadLuaScript( const char* LuaFileName )
{

    try
    {
     //LuaScript->GetGlobals().RegisterDirect( "Thinking", *this, &CAICharacterCore::Thinking );

     //////////////////////////////////////////////////////////////////////////

     LuaObject metaTableObj = m_LuaScript->GetGlobals().CreateTable("MultiObjectMetaTable");
     metaTableObj.SetObject("__index", metaTableObj);
     //metaTableObj.RegisterObjectFunctor( "ClearMoveStep", &CAICharacterCore::ClearMoveStep );
     //metaTableObj.RegisterObjectFunctor( "RestoreHPInstant", &CAICharacterCore::RestoreHPInstant );
     //metaTableObj.RegisterObjectDirect( "SetSayTimeInterval", (CAICharacterCore*)0, &CAICharacterCore::SetSayTimeInterval );

     metaTableObj.RegisterObjectDirect( "LoseHPInstant", (CAICharacterCore*)0, &CAICharacterCore::LoseHPInstant );
     metaTableObj.RegisterObjectDirect( "LoseMPInstant", (CAICharacterCore*)0, &CAICharacterCore::LoseMPInstant );
     metaTableObj.RegisterObjectDirect( "RestoreHPInstant", (CAICharacterCore*)0, &CAICharacterCore::RestoreHPInstant );
     metaTableObj.RegisterObjectDirect( "RestoreMPInstant", (CAICharacterCore*)0, &CAICharacterCore::RestoreMPInstant );
     metaTableObj.RegisterObjectDirect( "GetHP", (CAICharacterCore*)0, &CAICharacterCore::GetHP );
     metaTableObj.RegisterObjectDirect( "GetMP", (CAICharacterCore*)0, &CAICharacterCore::GetMP );
     metaTableObj.RegisterObjectDirect( "GetHPMax", (CAICharacterCore*)0, &CAICharacterCore::GetHPMax );
     metaTableObj.RegisterObjectDirect( "GetMPMax", (CAICharacterCore*)0, &CAICharacterCore::GetMPMax );
     metaTableObj.RegisterObjectDirect( "UseSkill", (CAICharacterCore*)0, &CAICharacterCore::UseSkill );
     metaTableObj.RegisterObjectDirect( "Say", (CAICharacterCore*)0, &CAICharacterCore::Say );
     metaTableObj.RegisterObjectDirect( "SayAdvance", (CAICharacterCore*)0, &CAICharacterCore::SayAdvance );
     metaTableObj.RegisterObjectDirect( "GetRand", (CAICharacterCore*)0, &CAICharacterCore::GetRand );
     metaTableObj.RegisterObjectDirect( "GetLevel", (CAICharacterCore*)0, &CAICharacterCore::GetLevel );
     metaTableObj.RegisterObjectDirect( "DropItemRand", (CAICharacterCore*)0, &CAICharacterCore::DropItemRand );
     metaTableObj.RegisterObjectDirect( "AddTimer", (CAICharacterCore*)0, &CAICharacterCore::AddTimer );
     metaTableObj.RegisterObjectDirect( "GetTimer", (CAICharacterCore*)0, &CAICharacterCore::GetTimer );
     metaTableObj.RegisterObjectDirect( "GetTargetHP", (CAICharacterCore*)0, &CAICharacterCore::GetTargetHP );
     metaTableObj.RegisterObjectDirect( "GetTargetMP", (CAICharacterCore*)0, &CAICharacterCore::GetTargetMP );
     metaTableObj.RegisterObjectDirect( "GetTargetHPMax", (CAICharacterCore*)0, &CAICharacterCore::GetTargetHPMax );
     metaTableObj.RegisterObjectDirect( "GetTargetMPMax", (CAICharacterCore*)0, &CAICharacterCore::GetTargetMPMax );
     metaTableObj.RegisterObjectDirect( "GetTargetLevel", (CAICharacterCore*)0, &CAICharacterCore::GetTargetLevel );
     metaTableObj.RegisterObjectDirect( "GetTargetEnmity", (CAICharacterCore*)0, &CAICharacterCore::GetTargetEnmity );
     metaTableObj.RegisterObjectDirect( "SetTargetEnmity", (CAICharacterCore*)0, &CAICharacterCore::SetTargetEnmity );
        metaTableObj.RegisterObjectDirect( "GetTargetDistance", (CAICharacterCore*)0, &CAICharacterCore::GetTargetDistance );
        metaTableObj.RegisterObjectDirect( "SetArray", (CAICharacterCore*)0, &CAICharacterCore::SetArray );
     metaTableObj.RegisterObjectDirect( "GetArray", (CAICharacterCore*)0, &CAICharacterCore::GetArray );
     metaTableObj.RegisterObjectDirect( "SetBoolArray", (CAICharacterCore*)0, &CAICharacterCore::SetBoolArray );
     metaTableObj.RegisterObjectDirect( "GetBoolArray", (CAICharacterCore*)0, &CAICharacterCore::GetBoolArray );

     metaTableObj.RegisterObjectDirect( "SelfMurder", (CAICharacterCore*)0, &CAICharacterCore::SelfMurder );

     //metaTableObj.RegisterObjectDirect( "GetTargetName", (CAICharacterCore*)0, &CAICharacterCore::GetTargetName );

     LuaObject CAICharacterCoreObj = m_LuaScript->BoxPointer(this);

     CAICharacterCoreObj.SetMetaTable(metaTableObj);

     m_LuaScript->GetGlobals().SetObject( "AI", CAICharacterCoreObj );

     if( !m_LuaScript->LoadFile( LuaFileName ) )
     {
      m_bLuaScriptLoaded = true;
      m_LuaScript->Call( 0, 0 );
     }

     //LuaStateOwner LuaScript;
     //LuaScript->LoadFile( "D:/ArenWorkstation/XSanguoRun/Server/Script/AI/test.lua" );
     //LuaObject luaFun = LuaScript->GetGlobal( "Event_OnInit" );

     //if( luaFun.IsFunction() )
     //{
     // int y = 0;
     //}

     //m_LuaScript->DoString("print(obj1:ClearMoveStep())");
     //LuaScript->LoadFile( "D:/ArenWorkstation/XSanguoRun/Server/test.lua" );
    }
    catch (LuaPlus::LuaException &e)
    {
        char szErr[1024] = {0};
        _snprintf(szErr, sizeof(szErr)-1, "怪物 %s AI脚本载入错误�Q?nbsp;%s", m_data.szCharacterName, e.GetErrorMessage());
        GetErrorLog()->logString(szErr);
        m_bLuaScriptLoaded = false;
    }

}

Let me see see 2010-09-06 18:18 发表评论