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].idstd::map<unsigned, BattleResultDamageData>::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:

<Info>0409-210505 654 Lookup local var buffAtk<Info>0409-210505 654 name = buffAtk type = table value = 0CB685A0<Info>0409-210505 654 name = buffAtk[1] type = table value = 06CCEA58<Info>0409-210505 670 name = buffAtk[1][dmg] type = number value = 89298<Info>0409-210505 670 name = buffAtk[1][skin] type = number value = 0<Info>0409-210505 670 name = buffAtk[1][star] type = number value = 6<Info>0409-210505 689 name = buffAtk[1][evo] type = number value = 10<Info>0409-210505 692 name = buffAtk[1][id] type = number value = 25165827<Info>0409-210505 693 name = buffAtk[1][lv] type = number value = 131<Info>0409-210505 693 name = buffAtk[1][icon] type = number value = 1090<Info>0409-210505 693 name = buffAtk[1][pos] type = number value = 19<Info>0409-210505 693 name = buffAtk[2] type = table value = 0CC8C038<Info>0409-210505 693 name = buffAtk[2][dmg] type = number value = 28726<Info>0409-210505 693 name = buffAtk[2][skin] type = number value = 0<Info>0409-210505 710 name = buffAtk[2][star] type = number value = 6<Info>0409-210505 711 name = buffAtk[2][evo] type = number value = 12<Info>0409-210505 711 name = buffAtk[2][id] type = number value = 25165828<Info>0409-210505 711 name = buffAtk[2][lv] type = number value = 90<Info>0409-210505 711 name = buffAtk[2][icon] type = number value = 1325<Info>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tableint i = 1;std::map<unsigned, BattleResultDamageData>::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tablei = 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：

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

<Info>0409-212740 450 Lookup local var buffDef<Info>0409-212740 451 name = buffDef type = table value = 0CDD1EB8<Info>0409-212740 451 name = buffDef[1] type = table value = 0CEEFCA8<Info>0409-212740 451 name = buffDef[1][dmg] type = number value = 1992<Info>0409-212740 451 name = buffDef[1][skin] type = number value = 0<Info>0409-212740 466 name = buffDef[1][star] type = number value = 1<Info>0409-212740 466 name = buffDef[1][evo] type = number value = 4<Info>0409-212740 466 name = buffDef[1][id] type = number value = 25165829<Info>0409-212740 482 name = buffDef[1][lv] type = number value = 85<Info>0409-212740 482 name = buffDef[1][icon] type = number value = 1005<Info>0409-212740 482 name = buffDef[1][pos] type = number value = 2<Info>0409-212740 482 name = buffDef[2] type = table value = 0CEED4D0<Info>0409-212740 482 name = buffDef[2][dmg] type = number value = 2941<Info>0409-212740 482 name = buffDef[2][skin] type = number value = 0<Info>0409-212740 499 name = buffDef[2][star] type = number value = 2<Info>0409-212740 499 name = buffDef[2][evo] type = number value = 6<Info>0409-212740 499 name = buffDef[2][id] type = number value = 25165830<Info>0409-212740 499 name = buffDef[2][lv] type = number value = 85<Info>0409-212740 499 name = buffDef[2][icon] type = number value = 1075<Info>0409-212740 499 name = buffDef[2][pos] type = number value = 16<Info>0409-212740 499 name = buffDef[3] type = table value = 0D0E83A0<Info>0409-212740 516 name = buffDef[3][dmg] type = number value = 308<Info>0409-212740 519 name = buffDef[3][skin] type = number value = 1<Info>0409-212740 521 name = buffDef[3][star] type = number value = 0<Info>0409-212740 523 name = buffDef[3][evo] type = number value = 6<Info>0409-212740 523 name = buffDef[3][id] type = number value = 25165831<Info>0409-212740 523 name = buffDef[3][lv] type = number value = 85<Info>0409-212740 523 name = buffDef[3][icon] type = number value = 1080<Info>0409-212740 523 name = buffDef[3][pos] type = number value = 17<Info>0409-212740 523 name = buffDef[4] type = table value = 0CD85A00<Info>0409-212740 523 name = buffDef[4][dmg] type = number value = 792<Info>0409-212740 539 name = buffDef[4][skin] type = number value = 0<Info>0409-212740 539 name = buffDef[4][star] type = number value = 0<Info>0409-212740 539 name = buffDef[4][evo] type = number value = 0<Info>0409-212740 539 name = buffDef[4][id] type = number value = 25165832<Info>0409-212740 539 name = buffDef[4][lv] type = number value = 85<Info>0409-212740 539 name = buffDef[4][icon] type = number value = 1145<Info>0409-212740 539 name = buffDef[4][pos] type = number value = 30<Info>0409-212740 554 name = buffDef[5] type = table value = 0C7CF7F8<Info>0409-212740 554 name = buffDef[5][dmg] type = number value = 1608<Info>0409-212740 554 name = buffDef[5][skin] type = number value = 0<Info>0409-212740 554 name = buffDef[5][star] type = number value = 2<Info>0409-212740 554 name = buffDef[5][evo] type = number value = 4<Info>0409-212740 554 name = buffDef[5][id] type = number value = 25165833<Info>0409-212740 571 name = buffDef[5][lv] type = number value = 47<Info>0409-212740 574 name = buffDef[5][icon] type = number value = 1090<Info>0409-212740 577 name = buffDef[5][pos] type = number value = 19<Info>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<unsigned, BattleResultDamageData> *datas[] = {&SkillActObj::_BattleAtk, &SkillActObj::_BattleDef};for (unsigned i = 0; i < 2; ++i) {lua_newtable(L_);//new tableint j = 1;std::map<unsigned, BattleResultDamageData>::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！