lua_学习

 

1， 类型

local bTemp = true;
print(bTemp);

local iTemp = 0;
print(iTemp);

local szTemp = "Hello World";
print(szTemp .. ":" .. #szTemp);
szTemp = string.gsub(szTemp, "World", "Lua");
print(szTemp .. ":" .. #szTemp);

local tab = {}
for i=1, 10, 1
do
 if 5 ~= i then
  tab[i] = i;
 end
end
for i=1,#tab, 1
do
 print(tab[i]);
end

for i=1,table.maxn(tab), 1
do
 print(tab[i]);
end

 

 

2， 函数

local fun = function(x,y)
 return x + y;
end

local fun1 = function(x,y,funAdd)
 return x + y + funAdd(x,y);
end

print( fun(3,2));

print( fun1(3,2,fun));

local tab = {}
tab[1] = fun;
tab[2] = fun1;

print( tab[1](3,2));
print( tab[2](3,2,tab[1]));

--lua支持尾调用消除，即如果函数最后一条语句是调用其它函数，则当前函数会消除栈然后转到其它函数，从而避免递归时栈溢出问题。

local fun2;
fun2 = function(n)
 if 1 == n then
  return n;
 else
  return n+fun2(n-1);
 end
end

print( fun2(3));

function newCount()
 local dNum = 0
 local function Count() --[[ 闭包（双重函数): 外部变量成为静态变量]]
  dNum = dNum + 1
  return dNum
 end
 return  Count
end

print("...");
funCount = newCount()
funCount1 = newCount()
print(newCount())

print(funCount())
print(funCount())
print(funCount())

print(funCount1())
print(funCount1())
print(funCount1())

 

3， 迭代器

 

4， C里调用Lua

lua文件：

function newHellow()
 local function doHellow()
  return "Hello Lua"
 end
 return doHellow
end
funHellow = newHellow()

 

function newCount()
 local iCount = 0
 local function Count()
  iCount = iCount + 1
  return iCount
 end
 return Count
end
funCount = newCount()

 

function funAdd(x, y)
 local function doAdd()
  return x + y
 end
 return doAdd()
end

 

C++的文件：

/********************************************************************
 file name : LuaAPI.h
 author  :  Clark
 created  :  1:8:2011
 purpose  :
*********************************************************************/

#pragma once

extern "C"
{  
#include <lua.h> 
#include <lauxlib.h>   
#include <lualib.h>   
}

class LuaAPI
{
public:
 LuaAPI(void);
 virtual ~LuaAPI(void);
 void init(const char* file_name) throw(char*);
 bool operator()(const char* func, const char* sig, ...); //LuaAPI("func","di>d",x,y,&z)

private:
 void uninit();
 lua_State *m_pL;
};

 

 

//----------------------------

 

#include "LuaAPI.h"
#include <string.h>

#pragma comment(lib,"lua5.1.lib")  

LuaAPI::LuaAPI():m_pL(NULL)
{
}

LuaAPI::~LuaAPI()
{
 uninit();
}

void LuaAPI::init(const char* file_name) throw(char*)
{
 uninit();
 m_pL = lua_open();
 luaL_openlibs(m_pL);
    if( luaL_loadfile(m_pL, file_name))
 {
  char strError[512];
  strcpy(strError,"Failed in init -> ");
  strncat(strError,file_name,256);
  strcat(strError,"\n");
  throw strError;
 }
 lua_resume(m_pL, 0);
}

void LuaAPI::uninit()
{
 if( NULL != m_pL)
 {
  lua_close(m_pL);
 }
}

//LuaAPI("func","di>d",x,y,&z)
bool LuaAPI::operator()(const char* func, const char* sig, ...)
{
 if( NULL == m_pL)
  return false;

 va_list vl;
 int narg, nres;
 va_start(vl, sig);
 lua_getglobal(m_pL,func);

 //压入参数
 for(narg = 0; *sig; narg++)
 {
  luaL_checkstack(m_pL, 1, "too many arguments");
  switch(*sig++)
  {
  case 'd': lua_pushnumber(m_pL, va_arg(vl, double)); break;
  case 'i': lua_pushinteger(m_pL, va_arg(vl, int)); break;
  case 's': lua_pushstring(m_pL, va_arg(vl, char*)); break;
  case '>': goto endargs;
  default: NULL;
  }
 }
endargs:

 nres = strlen(sig);
 if( 0 != lua_pcall(m_pL, narg, nres, 0))
 {
  //error(m_pL,"error calling '%s': %s", func, lua_tostring(m_pL,-1));
  return false;
 }

 //检索结果
 nres = -nres;
 while(*sig)
 {
  switch(*sig++)
  {
  case 'd': 
   {
    if(!lua_isnumber(m_pL, nres))
      break;
    *va_arg(vl, double*) = lua_tonumber(m_pL,nres);
   }
   break; 
  case 'i': 
   {
    if(!lua_isnumber(m_pL, nres))
      break;
    *va_arg(vl, int*) = lua_tointeger(m_pL,nres);
   }
   break; 
  case 's': 
   {
    if(!lua_isstring(m_pL, nres))
      break;
    *va_arg(vl, const char**) = lua_tostring(m_pL,nres);
   }
   break; 
  default: NULL;
  }
  nres++;
 }

 va_end(vl);
 return true;
}

 

//--------------------

 

#include <iostream>  
#include "LuaAPI.h"

using namespace std;

void main()
{

 int iSum = 0;

 LuaAPI lua_test;
 LuaAPI lua_test1;
 try
 {
  lua_test.init("lua_test.lua");
  lua_test1.init("lua_test1.lua");
 }
 catch(char* pError)
 {
  cout<<pError<<endl;
  system("pause");
  exit(0);
 }

 lua_test("funAdd", "ii>i", 2,3,&iSum);
 printf("%d\n",iSum);
 lua_test1("funAdd", "ii>i", 5,6,&iSum);
 printf("%d\n",iSum);

 system("pause");
}