diff --git a/luprex/core/cpp/table.cpp b/luprex/core/cpp/table.cpp
index 51347772..05cb235d 100644
--- a/luprex/core/cpp/table.cpp
+++ b/luprex/core/cpp/table.cpp
@@ -7,26 +7,27 @@
 
 bool table_equal(LuaStack &LS, LuaSlot t1, LuaSlot t2) {
     lua_State *L = LS.state();
+    int top = lua_gettop(L);
     LS.checktable(t1);
     LS.checktable(t2);
+    int nkeys1 = lua_nkeys(L, t1.index());
+    int nkeys2 = lua_nkeys(L, t2.index());
+    if (nkeys1 != nkeys2) return false;
+    int total = 0;
     lua_pushnil(L);
-    int total1 = 0;
     while (lua_next(L, t1.index()) != 0) {
         lua_pushvalue(L, -2);   // k v1 k
         lua_rawget(L, t2.index());  // k v1 v2
         if (!lua_rawequal(L, -1, -2)) {
+            lua_settop(L, top);
             return false;
         }
         lua_pop(L, 2);
-        total1 += 1;
+        total += 1;
     }
-    int total2 = 0;
-    lua_pushnil(L);
-    while (lua_next(L, t2.index()) != 0) {
-        lua_pop(L, 1);
-        total2 += 1;
-    }
-    return total1 == total2;
+    assert(total == nkeys1);
+    lua_settop(L, top);
+    return true;
 }
 
 LuaDefine(table_equal, "table1,table2", "return true if two tables contain the same keys and values") {
@@ -103,7 +104,7 @@ LuaDefine(table_find, "vector,value", "find the first occurrence of value in vec
     }
 }
 
-LuaDefine(table_empty, "table", "return true if the table is empty") {
+LuaDefine(table_empty, "table", "return true if the table has zero keys") {
     luaL_checktype(L, -1, LUA_TTABLE);
     int total = lua_nkeys(L, -1);
     lua_pushboolean(L, (total == 0)?1:0);