lua与c++的相互调用、C/C++修改Lua中Table的内容

一、lua与c++的相互调用

1.1 lua调用C++

在lua中是以函数指针的形式调用函数, 并且所有的函数指针都必须满足如下此种类型:

typedef int (*lua_CFunction) (lua_State *L);　　

也就是说, 偶们在C++中定义函数时必须以lua_State为参数, 以int为返回值才能被Lua所调用. 但是不要忘记了, 偶们的lua_State是支持栈的, 所以通过栈可以传递无穷个参数, 大小只受内存大小限制. 而返回的int值也只是指返回值的个数真正的返回值都存储在lua_State的栈中. 偶们通常的做法是做一个wrapper, 把所有需要调用的函数都wrap一下, 这样就可以调用任意的函数了.

[cpp]
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#include<iostream>
usingnamespace std;
#include<stdio.h>
extern"C" {
#include <lua.h>
#include <lualib.h>
#include <lauxlib.h>
}
//#pragma comment(lib, "lua5.1.lib")
lua_State* L;
staticint average(lua_State *L)
{
//返回栈中元素的个数
int n = lua_gettop(L);
double sum = 0;
int i;
for (i = 1; i <= n; i++)
{
if (!lua_isnumber(L, i))
{
lua_pushstring(L, "Incorrect argument to 'average'");
lua_error(L);
}
sum += lua_tonumber(L, i);
}
/* push the average */
lua_pushnumber(L, sum / n);
/* push the sum */
lua_pushnumber(L, sum);

/* return the number of results */
return 2;
}
int main (int argc,char*argv[])
{
/* initialize Lua */
L = lua_open();
/* load Lua libraries */
luaL_openlibs(L);
/* register our function */
lua_register(L, "average", average);
/* run the script */
luaL_dofile(L, "e15.lua");

lua_getglobal(L,"avg");
cout<<"avg is:"<<lua_tointeger(L,-1)<<endl;
lua_pop(L,1);
lua_getglobal(L,"sum");
cout<<"sum is:"<<lua_tointeger(L,-1)<<endl;
/* cleanup Lua */
lua_close(L);

return 0;
}
//程序
//*lua_gettop()的作用是返回栈顶元素的序号. 由于Lua的栈是从1开始编号的,
// 所以栈顶元素的序号也相当于栈中的元素个数. 在这里, 栈中元素的个数就
// 是传入的参数个数.

//* for循环计算所有传入参数的总和. 这里用到了数值转换lua_tonumber().
//* 然后偶们用lua_pushnumber()把平均值和总和push到栈中.
//* 最后, 偶们返回2, 表示有两个返回值.
//* 虽然在C++中定义了average()函数, 但Lua程序并不知道, 所以需
// 要在main函数中加入
// // register our function
// lua_register(L, "average", average);
//　　这两行的作用就是告诉e15.lua有average()这样一个函数.
//* 这个程序可以存成cpp也可以存成c, 如果以.c为扩展名就不需要加extern "C"
// 　　
//编译的方法偶们上次说过了, 方法相同.
//e15.lua执行的方法只能用上例中的C++中执行, 而不能用命令行方式执行.*/

[cpp]
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#include "stdafx.h"
#include <stdio.h>
extern"C" {
#include "lua.h"
#include "lualib.h"
#include "lauxlib.h"
}
/* Lua解释器指针 */
lua_State* L;
int main (int argc,char
*argv[] )
{
/* 初始化Lua */
L = lua_open();
/* 载入Lua基本库 */
luaL_openlibs(L);
/* 运行脚本 */
luaL_dofile(L, "Lua1.lua");
/* 清除Lua */
lua_close(L);
/* 暂停 */
printf( "Press enter to exit…" );
getchar();
return 0;
}

#include "stdafx.h"
#include <stdio.h>
extern "C" {
#include "lua.h"
#include "lualib.h"
#include "lauxlib.h"
}
/* Lua解释器指针 */
lua_State* L;
int main ( int argc, char *argv[] )
{
/* 初始化Lua */
L = lua_open();
/* 载入Lua基本库 */
luaL_openlibs(L);
/* 运行脚本 */
luaL_dofile(L, "Lua1.lua");
/* 清除Lua */
lua_close(L);
/* 暂停 */
printf( "Press enter to exit…" );
getchar();
return 0;
}

[cpp]
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/* A simple Lua interpreter. */
#include <stdio.h>
extern"C" {
#include <lua.h>
#include <lualib.h>
#include <lauxlib.h>
}
#include <stdio.h>
extern"C" {//
这是个C++程序, 所以要extern "C",
// 因为lua的头文件都是C格式的
#include "lua.h"
#include "lualib.h"
#include "lauxlib.h"
}
#pragma comment(lib, "lua5.1.lib")
/* the Lua interpreter */
lua_State* L;
int luaadd (int x,int
y )
{
int sum;
/* the function name */
lua_getglobal(L, "add");int nTop = lua_gettop(L);//得到栈的元素个数。栈顶的位置。

/* the first argument */
lua_pushnumber(L, x); nTop = lua_gettop(L);
/* the second argument */
lua_pushnumber(L, y); nTop = lua_gettop(L);
/* call the function with 2
arguments, return 1 result */
lua_call(L, 2, 1); nTop = lua_gettop(L);
/* get the result */
sum = (int)lua_tonumber(L, -1); nTop = lua_gettop(L);
/*清掉返回值*/
lua_pop(L, 1); nTop = lua_gettop(L);
/*取出脚本中的变量z的值*/
lua_getglobal(L, "z"); nTop = lua_gettop(L);
int z = (int)lua_tonumber(L, 1);nTop = lua_gettop(L);
lua_pop(L, 1); nTop = lua_gettop(L);

//没调通
/*lua_pushnumber(L, 4); nTop = lua_gettop(L);
lua_setglobal(L, "r"); nTop = lua_gettop(L);
int r = (int)lua_tonumber(L, 1);nTop = lua_gettop(L);*/
return sum;
}
int main (int argc,char
*argv[] )
{
int sum;
/* initialize Lua */
L = lua_open();
/* load Lua base libraries */
//lua_baselibopen(L);
/* load the script */
luaL_dofile(L, "e12.lua");
/* call the add function */
sum = luaadd( 10, 15 );
/* print the result */
printf( "The sum is %d", sum );
/* cleanup Lua */
lua_close(L);
return 0;
}
/*程序说明:
main中过程偶们上次已经说过了, 所以这次只说说luaadd的过程
* 首先用lua_getglobal()把add函数压栈
* 然后用lua_pushnumber()依次把x,y压栈
* 然后调用lua_call(), 并且告诉程序偶们有两个参数一个返回值
* 接着偶们从栈顶取回返回值, 用lua_tonumber()
* 最后偶们用lua_pop()把返回值清掉
*/

/* A simple Lua interpreter. */
#include <stdio.h>
extern "C" {
#include <lua.h>
#include <lualib.h>
#include <lauxlib.h>
}
#include <stdio.h>
extern "C" { // 这是个C++程序, 所以要extern "C",
// 因为lua的头文件都是C格式的
#include "lua.h"
#include "lualib.h"
#include "lauxlib.h"
}
#pragma comment(lib, "lua5.1.lib")
/* the Lua interpreter */
lua_State* L;
int luaadd ( int x, int y )
{
int sum;
/* the function name */
lua_getglobal(L, "add"); int nTop = lua_gettop(L); //得到栈的元素个数。栈顶的位置。
/* the first argument */
lua_pushnumber(L, x); nTop = lua_gettop(L);
/* the second argument */
lua_pushnumber(L, y); nTop = lua_gettop(L);
/* call the function with 2
arguments, return 1 result */
lua_call(L, 2, 1); nTop = lua_gettop(L);
/* get the result */
sum = (int)lua_tonumber(L, -1); nTop = lua_gettop(L);
/*清掉返回值*/
lua_pop(L, 1); nTop = lua_gettop(L);
/*取出脚本中的变量z的值*/
lua_getglobal(L, "z"); nTop = lua_gettop(L);
int z = (int)lua_tonumber(L, 1);nTop = lua_gettop(L);
lua_pop(L, 1); nTop = lua_gettop(L);

//没调通
/*lua_pushnumber(L, 4); nTop = lua_gettop(L);
lua_setglobal(L, "r"); nTop = lua_gettop(L);
int r = (int)lua_tonumber(L, 1);nTop = lua_gettop(L);*/
return sum;
}
int main ( int argc, char *argv[] )
{
int sum;
/* initialize Lua */
L = lua_open();
/* load Lua base libraries */
//lua_baselibopen(L);
/* load the script */
luaL_dofile(L, "e12.lua");
/* call the add function */
sum = luaadd( 10, 15 );
/* print the result */
printf( "The sum is %d", sum );
/* cleanup Lua */
lua_close(L);
return 0;
}
/*程序说明:
main中过程偶们上次已经说过了, 所以这次只说说luaadd的过程
* 首先用lua_getglobal()把add函数压栈
* 然后用lua_pushnumber()依次把x,y压栈
* 然后调用lua_call(), 并且告诉程序偶们有两个参数一个返回值
* 接着偶们从栈顶取回返回值, 用lua_tonumber()
* 最后偶们用lua_pop()把返回值清掉
*/

脚本为：

-- add two numbers

function add ( x, y )

return x + y + 2

end

z = 6

二、C/C++修改Lua中的Table的内容

WriteLuaTable.lua

luat_Test1={a=123, b=456, c=789} luat_Test2={123, 456, 789}

WriteLuaTable.cpp

#include <lua.hpp> static void WriteTableFromKey(lua_State *L, const char* lpszTableName, const char* lpszTableItem, int nVal) { lua_getglobal(L, lpszTableName); lua_pushnumber(L, nVal); lua_setfield(L, -2, lpszTableItem); lua_pop(L, 1); } static void WriteTableFromIndex(lua_State *L, const char* lpszTableName, int index, int nVal) { lua_getglobal(L, lpszTableName); lua_pushnumber(L, nVal); lua_rawseti(L, -2, index); lua_pop(L, 1); } static void ReadTableFromKey(lua_State *L, const char* lpszTableName, const char* lpszTableItem) { lua_getglobal(L, lpszTableName); lua_pushstring(L, lpszTableItem); lua_gettable(L, -2); printf("%s.%s=%d\n", lpszTableName, lpszTableItem, (int)lua_tonumber(L, -1)); lua_pop(L, 2); } static void ReadTableFromIndex(lua_State *L, const char* lpszTableName, int index) { lua_getglobal(L, lpszTableName); lua_rawgeti(L, -1, index); printf("%s[%d]=%d\n", lpszTableName, index, (int)lua_tonumber(L, -1)); lua_pop(L, 2); } int main (int argc, char* argv[]) { lua_State *L = lua_open(); luaopen_base(L); luaL_dofile(L, "WriteLuaTable.lua"); ReadTableFromKey(L, "luat_Test1", "a"); ReadTableFromKey(L, "luat_Test1", "b"); ReadTableFromKey(L, "luat_Test1", "c"); puts("\n"); WriteTableFromKey(L, "luat_Test1", "a", 147); // luat_Test1['a'] = 147 WriteTableFromKey(L, "luat_Test1", "b", 258); // luat_Test1['b'] = 258 WriteTableFromKey(L, "luat_Test1", "c", 369); // luat_Test1['c'] = 369 WriteTableFromKey(L, "luat_Test1", "d", 159); // luat_Test1['d'] = 159 ReadTableFromKey(L, "luat_Test1", "a"); ReadTableFromKey(L, "luat_Test1", "b"); ReadTableFromKey(L, "luat_Test1", "c"); ReadTableFromKey(L, "luat_Test1", "d"); puts("\n--------------------------"); ReadTableFromIndex(L, "luat_Test2", 1); ReadTableFromIndex(L, "luat_Test2", 2); ReadTableFromIndex(L, "luat_Test2", 3); puts("\n"); WriteTableFromIndex(L, "luat_Test2", 1, 147); // luat_Test2[1] = 147 WriteTableFromIndex(L, "luat_Test2", 2, 258); // luat_Test2[2] = 258 WriteTableFromIndex(L, "luat_Test2", 3, 369); // luat_Test2[3] = 369 WriteTableFromIndex(L, "luat_Test2", 4, 159); // luat_Test2[4] = 159 ReadTableFromIndex(L, "luat_Test2", 1); ReadTableFromIndex(L, "luat_Test2", 2); ReadTableFromIndex(L, "luat_Test2", 3); ReadTableFromIndex(L, "luat_Test2", 4); lua_close(L); return 0; }