Lua编程示例（五）： C语言对Lua表的读取和添加

#include "stdafx.h"

lua_State *L;


void load_lua(char *filename){
 L=luaL_newstate();
 luaL_openlibs(L);
 if((luaL_loadfile(L,filename) || lua_pcall(L,0,0,0))!= 0){
 luaL_error(L,"loadfile error! \n %s",lua_tostring(L,-1));
 }
}

double getfield(lua_State *L,char * key){
 double res;
 //默认栈顶是table，将key入栈
 lua_pushstring(L,key);
 lua_gettable(L,-2);  //查找键值为key的元素，置于栈顶
 if(!lua_isnumber(L,-1)){
 luaL_error(L,"num get error! %s\n",lua_tostring(L,-1));
 }
 res = lua_tonumber(L,-1);
 lua_pop(L,1); //删掉产生的查找结果
 return res;
}
void setfield(lua_State *L,char *key,double value){
 //默认栈顶是table
 lua_pushstring(L,key);
 lua_pushnumber(L,value);
 lua_settable(L,-3); //将这一对键值设成元素
}

struct mycolor{
 char *name;
 unsigned char red,green,blue;
}Color[]={
 {"WIETH",1,1,1},
 {"BLACK",0,0,0},
 {"BLUE",0,0,1}
};
//先创建一个空的栈，填入元素，用lua_setglobal弹出表，并赋成全局变量
void setcolor(lua_State *L,struct mycolor col){
 lua_newtable(L);
 setfield(L,"r",col.red);
 setfield(L,"g",col.green);
 setfield(L,"b",col.blue);
 lua_setglobal(L,col.name);
}

void getcolor(lua_State *L,char *key){
 lua_getglobal(L,key);
 if(!lua_istable(L,-1)){
 luaL_error(L,"'background' is not a table! %s\n",lua_tostring(L,-1));
 }
 double red;
 double green;
 double blue; 
 red = getfield(L,"r");
 blue = getfield(L,"b");
 green = getfield(L,"g");
 printf("The %s color : red = %.2f ,green = %.2f ,blue = %.2f\n",key,red,green,blue);
}

int _tmain(int argc, _TCHAR* argv[])
{
 load_lua("test.lua");
 getcolor(L,"background");
 int i = 0;
 while(Color[i].name != NULL){
 setcolor(L,Color[i]);
 i++;
 }
 getcolor(L,"WIETH");
 getcolor(L,"BLUE");
 return 0;
}

test.lua 中就一行代码：

background = {r=1,g=0.5,b=0.7}  

运行输出结果为：

The background color : red = 1.00 ,green = 0.50 ,blue = 0.70
The WIETH color : red = 1.00 ,green = 1.00 ,blue = 1.00
The BLUE color : red = 0.00 ,green = 0.00 ,blue = 1.00