Lua: 在C++中将table如何传入到lua中

 例一是参考别人的：

 //定义函数(返回table)
 int func_return_table(lua_State *L)
 {
  lua_newtable(L);//创建一个表格，放在栈顶
  lua_pushstring(L, "mydata");//压入key
  lua_pushnumber(L,66);//压入value
  lua_settable(L,-3);//弹出key,value，并设置到table里面去

  lua_pushstring(L, "subdata");//压入key
  lua_newtable(L);//压入value,也是一个table
  lua_pushstring(L, "mydata");//压入subtable的key
  lua_pushnumber(L,53);//value
  lua_settable(L,-3);//弹出key,value,并设置到subtable

  lua_settable(L,-3);//这时候父table的位置还是-3,弹出key,value(subtable),并设置到table里去
  lua_pushstring(L, "mydata2");//同上
  lua_pushnumber(L,77);
  lua_settable(L,-3);
  return 1;//堆栈里现在就一个table.其他都被弹掉了。
 }

输出结构体：

 {
      "mydata" = 66,
      "mydate2" = 77,
      "subdata" =
      {
           "mydata" = 53
      }
 }

这里算是一个嵌套的结构体了。

函数解释：

 lua_settable(lua_State* L, int index)

就是把表在lua堆栈中的值弹出来，index 是table 在堆栈中的位置，假如 table 在 -3, 则key 应该是 -2，value 是 -1

相当于 table[key] = value.

例二：

在工作中这里我想用一个类似数组的table,类似 tableaname[n].x

代码：

 struct BattleResultDamageData
 {
     Uint32 nIcon;
     Uint32 nDamage;
     Uint16 nPetPos;
     Uint16 nLv;
     Uint8  nStar;
     Uint8  nEvo;
     Uint8  nCurSkin;
     Uint8  nStage;
 };

 static int luaGetBattleResultData(lua_State *L_)
 {
     lua_newtable(L_); //创建一个表，放在栈顶
     int i = 1; //目的：类似tablename[i].id
     std::map::const_iterator map_it;
     for (map_it = SkillActObj::_BattleAtk.begin(); map_it != SkillActObj::_BattleAtk.end(); ++map_it,++i) //可忽略，目的遍历C++中的数据放在lua的table
     {
         lua_pushnumber(L_,i);
         lua_newtable(L_);
         lua_pushstring(L_,"id");
         lua_pushnumber(L_,map_it->first);
         lua_settable(L_,-3);//弹出key,value，并设置到table里面去
         lua_pushstring(L_,"dmg");
         lua_pushnumber(L_,map_it->second.nDamage);
         lua_settable(L_,-3);
         lua_pushstring(L_,"icon");
         lua_pushnumber(L_,map_it->second.nIcon);
         lua_settable(L_,-3);
         lua_pushstring(L_,"lv");
         lua_pushnumber(L_,map_it->second.nLv);
         lua_settable(L_,-3);
         lua_pushstring(L_,"star");
         lua_pushnumber(L_,map_it->second.nStar);
         lua_settable(L_,-3);
         lua_pushstring(L_,"evo");
         lua_pushnumber(L_,map_it->second.nEvo);
         lua_settable(L_,-3);
         lua_pushstring(L_,"pos");
         lua_pushnumber(L_,map_it->second.nPetPos);
         lua_settable(L_,-3);
         lua_pushstring(L_,"skin");
         lua_pushnumber(L_,map_it->second.nCurSkin);
         lua_settable(L_,-3);

         lua_settable(L_,-3);
     }
         return 1;
 }

在lua代码中的使用：

 local buffAtk = _G.getBattleResultData();

打印的buffAtk这个table结构体信息:

 0409-210505 654 Lookup local var buffAtk
 0409-210505 654 name = buffAtk   type = table    value = 0CB685A0
 0409-210505 654 name = buffAtk[1]    type = table    value = 06CCEA58
 0409-210505 670 name = buffAtk[1][dmg]   type = number   value = 89298
 0409-210505 670 name = buffAtk[1][skin]  type = number   value = 0
 0409-210505 670 name = buffAtk[1][star]  type = number   value = 6
 0409-210505 689 name = buffAtk[1][evo]   type = number   value = 10
 0409-210505 692 name = buffAtk[1][id]    type = number   value = 25165827
 0409-210505 693 name = buffAtk[1][lv]    type = number   value = 131
 0409-210505 693 name = buffAtk[1][icon]  type = number   value = 1090
 0409-210505 693 name = buffAtk[1][pos]   type = number   value = 19
 0409-210505 693 name = buffAtk[2]    type = table    value = 0CC8C038
 0409-210505 693 name = buffAtk[2][dmg]   type = number   value = 28726
 0409-210505 693 name = buffAtk[2][skin]  type = number   value = 0
 0409-210505 710 name = buffAtk[2][star]  type = number   value = 6
 0409-210505 711 name = buffAtk[2][evo]   type = number   value = 12
 0409-210505 711 name = buffAtk[2][id]    type = number   value = 25165828
 0409-210505 711 name = buffAtk[2][lv]    type = number   value = 90
 0409-210505 711 name = buffAtk[2][icon]  type = number   value = 1325
 0409-210505 711 name = buffAtk[2][pos]   type = number   value = 51

例三：

上例返回一个，这里我想返回两个tableaname[n].x
如：一个tablename1[n].x 与 另一个 tablename2[n].x

 static int luaGetBattleResultData(lua_State *L_)
 {
     lua_newtable(L_); // 建立一个table
     int i = 1;
     std::map::const_iterator map_it;
     for (map_it = SkillActObj::_BattleAtk.begin(); map_it != SkillActObj::_BattleAtk.end(); ++map_it,++i)
     {
         lua_pushnumber(L_,i);
         lua_newtable(L_);
         lua_pushstring(L_,"id");
         lua_pushnumber(L_,map_it->first);
         lua_settable(L_,-3);//弹出key,value，并设置到table里面去
         //...
         lua_pushstring(L_,"skin");
         lua_pushnumber(L_,map_it->second.nCurSkin);
         lua_settable(L_,-3);

         lua_settable(L_,-3);
     }

     lua_newtable(L_); //建立另一个table
     i = 1;
     for (map_it = SkillActObj::_BattleDef.begin(); map_it != SkillActObj::_BattleDef.end(); ++map_it,++i)
     {
         lua_pushnumber(L_,i);
         lua_newtable(L_);
         lua_pushstring(L_,"id");
         lua_pushnumber(L_,map_it->first);
         lua_settable(L_,-3);//弹出key,value，并设置到table里面去
         // ...
         lua_pushstring(L_,"skin");
         lua_pushnumber(L_,map_it->second.nCurSkin);
         lua_settable(L_,-3);

         lua_settable(L_,-3);
     }
     return 2; // 返回这两个table
 }

在lua中调用：

 local buffAtk, buffDef= _G.getBattleResultData();

打印这两个table的信息：

 0409-210505 654 Lookup local var buffAtk
 0409-210505 654 name = buffAtk   type = table    value = 0CB685A0
 0409-210505 654 name = buffAtk[1]    type = table    value = 06CCEA58
 0409-210505 670 name = buffAtk[1][dmg]   type = number   value = 89298
 0409-210505 670 name = buffAtk[1][skin]  type = number   value = 0
 0409-210505 670 name = buffAtk[1][star]  type = number   value = 6
 0409-210505 689 name = buffAtk[1][evo]   type = number   value = 10
 0409-210505 692 name = buffAtk[1][id]    type = number   value = 25165827
 0409-210505 693 name = buffAtk[1][lv]    type = number   value = 131
 0409-210505 693 name = buffAtk[1][icon]  type = number   value = 1090
 0409-210505 693 name = buffAtk[1][pos]   type = number   value = 19
 0409-210505 693 name = buffAtk[2]    type = table    value = 0CC8C038
 0409-210505 693 name = buffAtk[2][dmg]   type = number   value = 28726
 0409-210505 693 name = buffAtk[2][skin]  type = number   value = 0
 0409-210505 710 name = buffAtk[2][star]  type = number   value = 6
 0409-210505 711 name = buffAtk[2][evo]   type = number   value = 12
 0409-210505 711 name = buffAtk[2][id]    type = number   value = 25165828
 0409-210505 711 name = buffAtk[2][lv]    type = number   value = 90
 0409-210505 711 name = buffAtk[2][icon]  type = number   value = 1325
 0409-210505 711 name = buffAtk[2][pos]   type = number   value = 51
 0409-210505 711

 0409-212740 450 Lookup local var buffDef
 0409-212740 451 name = buffDef   type = table    value = 0CDD1EB8
 0409-212740 451 name = buffDef[1]    type = table    value = 0CEEFCA8
 0409-212740 451 name = buffDef[1][dmg]   type = number   value = 1992
 0409-212740 451 name = buffDef[1][skin]  type = number   value = 0
 0409-212740 466 name = buffDef[1][star]  type = number   value = 1
 0409-212740 466 name = buffDef[1][evo]   type = number   value = 4
 0409-212740 466 name = buffDef[1][id]    type = number   value = 25165829
 0409-212740 482 name = buffDef[1][lv]    type = number   value = 85
 0409-212740 482 name = buffDef[1][icon]  type = number   value = 1005
 0409-212740 482 name = buffDef[1][pos]   type = number   value = 2
 0409-212740 482 name = buffDef[2]    type = table    value = 0CEED4D0
 0409-212740 482 name = buffDef[2][dmg]   type = number   value = 2941
 0409-212740 482 name = buffDef[2][skin]  type = number   value = 0
 0409-212740 499 name = buffDef[2][star]  type = number   value = 2
 0409-212740 499 name = buffDef[2][evo]   type = number   value = 6
 0409-212740 499 name = buffDef[2][id]    type = number   value = 25165830
 0409-212740 499 name = buffDef[2][lv]    type = number   value = 85
 0409-212740 499 name = buffDef[2][icon]  type = number   value = 1075
 0409-212740 499 name = buffDef[2][pos]   type = number   value = 16
 0409-212740 499 name = buffDef[3]    type = table    value = 0D0E83A0
 0409-212740 516 name = buffDef[3][dmg]   type = number   value = 308
 0409-212740 519 name = buffDef[3][skin]  type = number   value = 1
 0409-212740 521 name = buffDef[3][star]  type = number   value = 0
 0409-212740 523 name = buffDef[3][evo]   type = number   value = 6
 0409-212740 523 name = buffDef[3][id]    type = number   value = 25165831
 0409-212740 523 name = buffDef[3][lv]    type = number   value = 85
 0409-212740 523 name = buffDef[3][icon]  type = number   value = 1080
 0409-212740 523 name = buffDef[3][pos]   type = number   value = 17
 0409-212740 523 name = buffDef[4]    type = table    value = 0CD85A00
 0409-212740 523 name = buffDef[4][dmg]   type = number   value = 792
 0409-212740 539 name = buffDef[4][skin]  type = number   value = 0
 0409-212740 539 name = buffDef[4][star]  type = number   value = 0
 0409-212740 539 name = buffDef[4][evo]   type = number   value = 0
 0409-212740 539 name = buffDef[4][id]    type = number   value = 25165832
 0409-212740 539 name = buffDef[4][lv]    type = number   value = 85
 0409-212740 539 name = buffDef[4][icon]  type = number   value = 1145
 0409-212740 539 name = buffDef[4][pos]   type = number   value = 30
 0409-212740 554 name = buffDef[5]    type = table    value = 0C7CF7F8
 0409-212740 554 name = buffDef[5][dmg]   type = number   value = 1608
 0409-212740 554 name = buffDef[5][skin]  type = number   value = 0
 0409-212740 554 name = buffDef[5][star]  type = number   value = 2
 0409-212740 554 name = buffDef[5][evo]   type = number   value = 4
 0409-212740 554 name = buffDef[5][id]    type = number   value = 25165833
 0409-212740 571 name = buffDef[5][lv]    type = number   value = 47
 0409-212740 574 name = buffDef[5][icon]  type = number   value = 1090
 0409-212740 577 name = buffDef[5][pos]   type = number   value = 19
 0409-212740 578

看到这，是不是感觉哪里不对？是不是感觉代码好臃肿？

下面是最最终优化后的代码：

 static void setTableInt(lua_State *L_, const char *sKey, lua_Number nVal)
 {
     lua_pushstring(L_, sKey);
     lua_pushnumber(L_, nVal);
     lua_settable(L_,-3);
 }

 static void newDmgTable(lua_State *L_, unsigned nEntityId, const BattleResultDamageData &data)
 {
     lua_newtable(L_);
     setTableInt(L_, "id", nEntityId);
     setTableInt(L_, "dmg", data.nDamage);
     setTableInt(L_, "icon", data.nIcon);
     setTableInt(L_, "lv", data.nLv);
     setTableInt(L_, "star", data.nStar);
     setTableInt(L_, "evo", data.nEvo);
     setTableInt(L_, "pos", data.nPetPos);
     setTableInt(L_, "skin", data.nCurSkin);
 }

 static int luaGetBattleResultData(lua_State *L_)
 {
     std::map *datas[] = {&SkillActObj::_BattleAtk, &SkillActObj::_BattleDef};
     for (unsigned i = 0; i < 2; ++i)
     {
         lua_newtable(L_);   //new table
         int j = 1;
         std::map::const_iterator map_it = datas[i]->begin(), map_it_end = datas[i]->end();
         for (; map_it != map_it_end; ++map_it, ++j) {
             lua_pushinteger(L_, j);
             newDmgTable(L_, map_it->first, map_it->second);   //atker or defer[id] = dmg_table;
             lua_settable(L_, -3);
         }
     }
     return 2;
 }

这下是不是感觉一下子少了好多？这就是代码的重用性！