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! %sn",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! %sn",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 = %.2fn",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