C遍歷lua的table

假設table的在stack中的索引位置爲index，如今從C代碼裏面對這個lua的table進行遍歷，方法以下：

方法一、當index爲正值的時候，可用以下代碼：

注意：t>0

void printtb(lua_State *L,int index)
{
    /* table is in the stack at index 'index' */
     lua_pushnil(L);  /* first key  若是index是負數，此時table的索引位置變化了：假如原來是-1，如今變成-2了*/
     while (lua_next(L, index) != 0) {
       /* uses 'key' (at index -2) and 'value' (at index -1) */
       printf("%s - %s\n",lua_tostring(L, -1), lua_tostring(L, -2));
              //lua_typename(L, lua_type(L, -2)),
              //lua_typename(L, lua_type(L, -1)));
       /* removes 'value'; keeps 'key' for next iteration */
       lua_pop(L, 1);
     }
}

方法二、index爲任意狀況：

static void iterate_and_print(lua_State *L, int index)
{
    // Push another reference to the table on top of the stack (so we know
    // where it is, and this function can work for negative, positive and
    // pseudo indices
    lua_pushvalue(L, index);
    // stack now contains: -1 => table
    lua_pushnil(L);
    // stack now contains: -1 => nil; -2 => table
    while (lua_next(L, -2))
    {
        // stack now contains: -1 => value; -2 => key; -3 => table
        // copy the key so that lua_tostring does not modify the original
        lua_pushvalue(L, -2);
        // stack now contains: -1 => key; -2 => value; -3 => key; -4 => table
        printf("%s => %s\n", lua_tostring(L, -1), lua_tostring(L, -2));
        // pop value + copy of key, leaving original key
        lua_pop(L, 2);
        // stack now contains: -1 => key; -2 => table
    }
    // stack now contains: -1 => table (when lua_next returns 0 it pops the key
    // but does not push anything.)
    // Pop table
    lua_pop(L, 1);
    // Stack is now the same as it was on entry to this function
}

參考：

http://www.lua.org/manual/5.2/manual.html#lua_next

http://stackoverflow.com/questions/6137684/iterate-through-lua-table

http://stackoverflow.com/questions/1438842/iterating-through-a-lua-table-from-c