diff --git a/luprex/cpp/core/animqueue.cpp b/luprex/cpp/core/animqueue.cpp
index 506ac0f8..6f486a27 100644
--- a/luprex/cpp/core/animqueue.cpp
+++ b/luprex/cpp/core/animqueue.cpp
@@ -171,7 +171,7 @@ void AnimStep::config_store_number(lua_State *L, int idx, float *target, float o
 void AnimStep::configure(LuaKeywordParser &kp, const AnimStep &aqback) {
     lua_State *L = kp.state();
     LuaVar value;
-    LuaOldStack LS(L, value);
+    LuaExtStack LS(L, value);
 
     if (kp.parse(value, "action")) {
         config_store_string(L, value.index(), &action_, 0, "action");
diff --git a/luprex/cpp/core/gui.cpp b/luprex/cpp/core/gui.cpp
index 96d31be7..475c7c82 100644
--- a/luprex/cpp/core/gui.cpp
+++ b/luprex/cpp/core/gui.cpp
@@ -59,7 +59,7 @@ eng::string Gui::menu_debug_string() const {
 LuaDefine(gui_menu_item, "action,label", "add a menu item to the current gui") {
     Gui *gui = Gui::fetch_global_pointer(L);
     LuaArg laction, llabel;
-    LuaOldStack LS(L, laction, llabel);
+    LuaDefStack LS(L, laction, llabel);
     eng::string action = LS.ckstring(laction);
     eng::string label = LS.ckstring(llabel);
     if (!sv::has_prefix(action, "cb_")) {
diff --git a/luprex/cpp/core/http.cpp b/luprex/cpp/core/http.cpp
index 367321ee..2a8ae3d2 100644
--- a/luprex/cpp/core/http.cpp
+++ b/luprex/cpp/core/http.cpp
@@ -683,7 +683,7 @@ void HttpClientRequest::set_params(LuaCoreStack &LS0, LuaSlot tab) {
         return;
     }
     LuaVar key, val;
-    LuaOldStack LS(LS0.state(), key, val);
+    LuaDefStack LS(LS0.state(), key, val);
     LS.set(key, LuaNil);
     while (LS.next(tab, key, val)) {
         set_param(LS, key, val);
@@ -736,7 +736,7 @@ void HttpClientRequest::set_defaults() {
 
 void HttpClientRequest::configure(LuaKeywordParser &kp) {
     LuaVar val;
-    LuaOldStack LS(kp.state(), val);
+    LuaExtStack LS(kp.state(), val);
     if (kp.parse(val, "method")) {
         set_method(LS, val);
     }
@@ -1032,7 +1032,7 @@ void HttpServerResponse::set_jsonvalue(LuaCoreStack &LS, LuaSlot val) {
 
 void HttpServerResponse::configure(LuaKeywordParser &kp) {
     LuaVar val;
-    LuaOldStack LS(kp.state(), val);
+    LuaExtStack LS(kp.state(), val);
     if (kp.parse(val, "status")) {
         set_status(LS, val);
     }
@@ -1470,7 +1470,7 @@ bool HttpParser::parse_content(std::string_view &view, bool closed) {
 
 void HttpParser::store(LuaCoreStack &LS0, LuaSlot tab) const {
     LuaVar ptab, djson;
-    LuaOldStack LS(LS0.state(), ptab, djson);
+    LuaExtStack LS(LS0.state(), ptab, djson);
 
     LS.newtable(tab);
     if (!is_request_) {
@@ -1659,7 +1659,7 @@ void HttpClientRequestMap::deserialize(StreamBuffer *sb) {
 LuaDefine(http_fixurl, "url", "validate URL and repair minor flaws in the URL syntax") {
     LuaArg url;
     LuaRet fixed;
-    LuaOldStack LS(L, url, fixed);
+    LuaDefStack LS(L, url, fixed);
     ParsedURL parsed(LS.ckstring(url));
     if (!parsed.valid) {
         luaL_error(L, "invalid URL, not fixable");
@@ -1715,7 +1715,7 @@ LuaDefine(http_clientrequest, "request",
     "|that would be sent.") {
     LuaArg tab;
     LuaRet str;
-    LuaOldStack LS(L, tab, str);
+    LuaDefStack LS(L, tab, str);
     LuaKeywordParser kp(LS, tab);
     HttpClientRequest req;
     req.configure(kp);
@@ -1774,7 +1774,7 @@ LuaDefine(http_clientresponse, "response",
     "|an actual HTTP response string.  This is for debugging only.") {
     LuaArg text;
     LuaRet tab;
-    LuaOldStack LS(L, text, tab);
+    LuaDefStack LS(L, text, tab);
     HttpParser parser;
     parser.parse_response(LS.ckstring(text), true, "GET");
     parser.store(LS, tab);
@@ -1829,7 +1829,7 @@ LuaDefine(http_serverrequest, "request",
     "|an actual HTTP request string.  This is for debugging only.") {
     LuaArg text;
     LuaRet tab;
-    LuaOldStack LS(L, text, tab);
+    LuaDefStack LS(L, text, tab);
     HttpParser parser;
     parser.parse_request(LS.ckstring(text), true);
     parser.store(LS, tab);
@@ -1887,7 +1887,7 @@ LuaDefine(http_serverresponse, "response",
     "|that would be sent.") {
     LuaArg tab;
     LuaRet str;
-    LuaOldStack LS(L, tab, str);
+    LuaDefStack LS(L, tab, str);
     LuaKeywordParser kp(LS, tab);
     HttpServerResponse resp;
     resp.configure(kp);
@@ -1901,7 +1901,7 @@ LuaDefine(http_serverresponse, "response",
 LuaDefine(http_validmime, "(mt)", "") {
     LuaArg str;
     LuaRet ok;
-    LuaOldStack LS(L, str, ok);
+    LuaDefStack LS(L, str, ok);
     LS.set(ok, valid_mime_type(LS.ckstring(str)));
     return LS.result();
 }
@@ -1909,7 +1909,7 @@ LuaDefine(http_validmime, "(mt)", "") {
 LuaDefine(http_statusstring, "(statuscode)", "Convert a 3-digit status code to a string") {
     LuaArg code;
     LuaRet str;
-    LuaOldStack LS(L, code, str);
+    LuaDefStack LS(L, code, str);
     int icode = LS.ckint(code);
     LS.set(str, status_code_to_string(icode));
     return LS.result();
@@ -1918,7 +1918,7 @@ LuaDefine(http_statusstring, "(statuscode)", "Convert a 3-digit status code to a
 LuaDefine(http_statuscode, "(statusstring)", "Convert a string to a 3-digit status code") {
     LuaArg str;
     LuaRet code;
-    LuaOldStack LS(L, code, str);
+    LuaDefStack LS(L, code, str);
     eng::string sstr = LS.ckstring(str);
     LS.set(code, status_code_from_string(sstr));
     int iresult = LS.result();
diff --git a/luprex/cpp/core/json.cpp b/luprex/cpp/core/json.cpp
index fb9b742e..75ccb650 100644
--- a/luprex/cpp/core/json.cpp
+++ b/luprex/cpp/core/json.cpp
@@ -311,7 +311,7 @@ static bool decode_number(lua_State *L, std::string_view &v) {
     // is OK.
     if (sv::valid_number(n, true, true, false, false)) {
         int64_t i = sv::to_int64(n);
-        if (!LuaOldStack::int64_storable(i)) return false;
+        if (!LuaCoreStack::int64_storable(i)) return false;
         lua_pushnumber(L, double(i));
         return true;
     } else {
@@ -361,7 +361,7 @@ static bool decode_int_string(lua_State *L, std::string_view &v) {
     // Make sure the number fits in a lua double,
     // and push it on the stack.
     int64_t i = sv::to_int64(n);
-    if (!LuaOldStack::int64_storable(i)) {
+    if (!LuaCoreStack::int64_storable(i)) {
         return false;
     }
     lua_pushnumber(L, double(i));
@@ -661,7 +661,7 @@ LuaDefine(json_encode, "data, indent, maxlen",
     "|") {
     LuaArg data, indent, maxlen;
     LuaRet encoded;
-    LuaOldStack LS(L, data, indent, maxlen, encoded);
+    LuaDefStack LS(L, data, indent, maxlen, encoded);
     eng::string out;
     eng::string error = json::encode(LS, data, out, LS.ckboolean(indent), LS.ckint(maxlen));
     if (!error.empty()) {
@@ -695,7 +695,7 @@ LuaDefine(json_decode, "data",
     "|") {
     LuaArg encoded;
     LuaRet data;
-    LuaOldStack LS(L, encoded, data);
+    LuaDefStack LS(L, encoded, data);
     std::string_view v = LS.ckstringview(encoded);
     bool ok = json::decode(LS, data, v);
     if (!ok) {
@@ -707,7 +707,7 @@ LuaDefine(json_decode, "data",
 // LuaDefine(base64_encode, "data", "") {
 //     LuaArg str;
 //     LuaRet ret;
-//     LuaOldStack LS(L, str, ret);
+//     LuaDefStack LS(L, str, ret);
 //     eng::string cstr = LS.ckstring(str);
 //     eng::ostringstream oss;
 //     util::base64_encode(cstr, &oss);
@@ -718,7 +718,7 @@ LuaDefine(json_decode, "data",
 // LuaDefine(base64_decode, "data", "") {
 //     LuaArg str;
 //     LuaRet ret;
-//     LuaOldStack LS(L, str, ret);
+//     LuaDefStack LS(L, str, ret);
 //     eng::string cstr = LS.ckstring(str);
 //     eng::ostringstream oss;
 //     util::base64_decode(cstr, &oss);
diff --git a/luprex/cpp/core/luastack.hpp b/luprex/cpp/core/luastack.hpp
index e8a8e3a3..0683412d 100644
--- a/luprex/cpp/core/luastack.hpp
+++ b/luprex/cpp/core/luastack.hpp
@@ -181,6 +181,7 @@ public:
     
     friend class LuaCoreStack;
     friend class LuaOldStack;
+    friend class LuaDefStack;
     friend class LuaExtStack;
 };
 
@@ -275,6 +276,8 @@ class LuaCoreStack : public eng::nevernew {
 protected:
     lua_State *L_;
     
+    LuaCoreStack(lua_State *L) : L_(L) {}
+    
 private:
     // Push any value on the stack, by type.
     void push_any_value(LuaNewTableMarker s) const { lua_newtable(L_); }
@@ -549,8 +552,7 @@ private:
 
 public:
     template<class... SS>
-    LuaOldStack(lua_State *L, SS & ... stackslots) {
-        L_ = L;
+    LuaOldStack(lua_State *L, SS & ... stackslots) : LuaCoreStack(L) {
         count_slots<0, 0, 0>(stackslots...);
         if (lua_gettop(L) < narg_) {
             luaL_error(L, "not enough arguments to function");
@@ -624,8 +626,7 @@ private:
 
 public:
     template<class... SS>
-    LuaDefStack(lua_State *L, SS & ... stackslots) {
-        L_ = L;
+    LuaDefStack(lua_State *L, SS & ... stackslots) : LuaCoreStack(L) {
         count_slots<0, 0, 0>(stackslots...);
         if (lua_gettop(L_) != narg_) {
             luaL_error(L_, "function expects exactly %d arguments", narg_);
@@ -642,11 +643,12 @@ public:
         assign_slots(1, 1 + nret_, 1 + nret_ + narg_, stackslots...);
     }
 
-    ~LuaDefStack() {
-        if (!lua_isthrowing(L_)) {
-            lua_settop(L_, nret_);
-        };
+    int result() {
+        lua_settop(L_, nret_);
+        return nret_;
     }
+
+    ~LuaDefStack() { }
 };
 
 class LuaExtStack : public LuaCoreStack {
@@ -673,8 +675,7 @@ private:
 
 public:
     template<class... SS>
-    LuaExtStack(lua_State *L, SS & ... stackslots) {
-        L_ = L;
+    LuaExtStack(lua_State *L, SS & ... stackslots) : LuaCoreStack(L) {
         count_slots<0>(stackslots...);
         lua_checkstack(L_, nvar_ + 20);
         oldtop_ = lua_gettop(L_);
@@ -685,8 +686,7 @@ public:
     }
 
     template<class... SS>
-    LuaExtStack(const LuaCoreStack &LS0, SS & ... stackslots) {
-        L_ = LS0.state();
+    LuaExtStack(const LuaCoreStack &LS0, SS & ... stackslots) : LuaCoreStack(LS0.state()) {
         count_slots<0>(stackslots...);
         lua_checkstack(L_, nvar_ + 20);
         oldtop_ = lua_gettop(L_);
diff --git a/luprex/cpp/core/table.cpp b/luprex/cpp/core/table.cpp
index b8b22771..53040aaa 100644
--- a/luprex/cpp/core/table.cpp
+++ b/luprex/cpp/core/table.cpp
@@ -33,7 +33,7 @@ bool table_equal(LuaCoreStack &LS, LuaSlot t1, LuaSlot t2) {
 LuaDefine(table_equal, "table1,table2", "return true if two tables contain the same keys and values") {
     LuaArg t1, t2;
     LuaRet eql;
-    LuaOldStack LS(L, t1, t2, eql);
+    LuaDefStack LS(L, t1, t2, eql);
     LS.set(eql, table_equal(LS, t1, t2));
     return LS.result();
 }
@@ -121,7 +121,7 @@ LuaDefine(table_count, "table", "return the number of keys in table") {
 LuaDefine(table_clear, "table,metaflag", "clear all keys, and optionally the metatable") {
     LuaArg tab, clearmeta;
     LuaVar metatable, metafield;
-    LuaOldStack LS(L, tab, clearmeta, metatable, metafield);
+    LuaDefStack LS(L, tab, clearmeta, metatable, metafield);
     LS.checktable(tab, "table");
     if (LS.ckboolean(clearmeta)) {
         LS.getmetatable(metatable, tab);
@@ -142,7 +142,7 @@ LuaDefine(table_clear, "table,metaflag", "clear all keys, and optionally the met
 LuaDefine(table_getflagbits, "table", "get the table's flag bits (debugging only)") {
     LuaArg tab;
     LuaRet bits;
-    LuaOldStack LS(L, tab, bits);
+    LuaDefStack LS(L, tab, bits);
     uint16_t ubits = lua_getflagbits(L, tab.index());
     LS.set(bits, ubits);
     return LS.result();
@@ -150,7 +150,7 @@ LuaDefine(table_getflagbits, "table", "get the table's flag bits (debugging only
 
 LuaDefine(table_setflagbits, "table,bits", "set the table's flag bits (debugging only)") {
     LuaArg tab, bits;
-    LuaOldStack LS(L, tab, bits);
+    LuaDefStack LS(L, tab, bits);
     uint16_t ubits = LS.ckinteger(bits);
     lua_setflagbits(L, tab.index(), ubits);
     return LS.result();
@@ -232,7 +232,7 @@ int deque_make_room(lua_State *L, int deque, int left, int fill, int max) {
 LuaDefine(deque_create, "", "create a deque") {
     LuaRet rdeque;
     LuaVar classobj;
-    LuaOldStack LS(L, rdeque, classobj);
+    LuaDefStack LS(L, rdeque, classobj);
     const int imax = 4;
     eng::string err = LS.getclass(classobj, "deque");
     if (err != "") {
@@ -251,7 +251,7 @@ LuaDefine(deque_create, "", "create a deque") {
 
 LuaDefine(deque_pushl, "deque,value", "push onto the left end of a deque") {
     LuaArg deque, elt;
-    LuaOldStack LS(L, deque, elt);
+    LuaDefStack LS(L, deque, elt);
     int left, fill, max;
     deque_get_info(L, deque.index(), &left, &fill, &max);
     max = deque_make_room(L, deque.index(), left, fill, max);
@@ -265,7 +265,7 @@ LuaDefine(deque_pushl, "deque,value", "push onto the left end of a deque") {
 
 LuaDefine(deque_pushr, "deque,value", "push onto the right end of a deque") {
     LuaArg deque, elt;
-    LuaOldStack LS(L, deque, elt);
+    LuaDefStack LS(L, deque, elt);
     int left, fill, max;
     deque_get_info(L, deque.index(), &left, &fill, &max);
     max = deque_make_room(L, deque.index(), left, fill, max);
@@ -279,7 +279,7 @@ LuaDefine(deque_pushr, "deque,value", "push onto the right end of a deque") {
 LuaDefine(deque_popl, "deque", "pop the left end of a deque") {
     LuaArg deque;
     LuaRet result;
-    LuaOldStack LS(L, deque, result);
+    LuaDefStack LS(L, deque, result);
     int left, fill, max;
     deque_get_info(L, deque.index(), &left, &fill, &max);
     if (fill == 0) {
@@ -297,7 +297,7 @@ LuaDefine(deque_popl, "deque", "pop the left end of a deque") {
 LuaDefine(deque_popr, "deque", "pop the right end of a deque") {
     LuaArg deque;
     LuaRet result;
-    LuaOldStack LS(L, deque, result);
+    LuaDefStack LS(L, deque, result);
     int left, fill, max;
     deque_get_info(L, deque.index(), &left, &fill, &max);
     if (fill == 0) {
@@ -315,7 +315,7 @@ LuaDefine(deque_popr, "deque", "pop the right end of a deque") {
 LuaDefine(deque_nthl, "deque,n", "return the nth item from the left end of a deque") {
     LuaArg deque, nn;
     LuaRet result;
-    LuaOldStack LS(L, deque, nn, result);
+    LuaDefStack LS(L, deque, nn, result);
     int left, fill, max;
     deque_get_info(L, deque.index(), &left, &fill, &max);
     int n = LS.ckint(nn);
@@ -331,7 +331,7 @@ LuaDefine(deque_nthl, "deque,n", "return the nth item from the left end of a deq
 LuaDefine(deque_nthr, "deque,n", "return the nth item from the right end of a deque") {
     LuaArg deque, nn;
     LuaRet result;
-    LuaOldStack LS(L, deque, nn, result);
+    LuaDefStack LS(L, deque, nn, result);
     int left, fill, max;
     deque_get_info(L, deque.index(), &left, &fill, &max);
     int n = LS.ckint(nn);
@@ -346,7 +346,7 @@ LuaDefine(deque_nthr, "deque,n", "return the nth item from the right end of a de
 
 LuaDefine(deque_setl, "deque,n,value", "set the nth item from the left end of a deque") {
     LuaArg deque, nn, val;
-    LuaOldStack LS(L, deque, nn, val);
+    LuaDefStack LS(L, deque, nn, val);
     int left, fill, max;
     deque_get_info(L, deque.index(), &left, &fill, &max);
     int n = LS.ckint(nn);
@@ -361,7 +361,7 @@ LuaDefine(deque_setl, "deque,n,value", "set the nth item from the left end of a
 
 LuaDefine(deque_setr, "deque,n,value", "set the nth item from the right end of a deque") {
     LuaArg deque, nn, val;
-    LuaOldStack LS(L, deque, nn, val);
+    LuaDefStack LS(L, deque, nn, val);
     int left, fill, max;
     deque_get_info(L, deque.index(), &left, &fill, &max);
     int n = LS.ckint(nn);
@@ -378,7 +378,7 @@ LuaDefine(deque_findl, "deque,value", "find the first occurence of value in dequ
     LuaArg deque, val;
     LuaRet pos;
     LuaVar check;
-    LuaOldStack LS(L, deque, val, pos, check);
+    LuaDefStack LS(L, deque, val, pos, check);
     int left, fill, max;
     deque_get_info(L, deque.index(), &left, &fill, &max);
     for (int i = 0; i < fill; i++) {
@@ -397,7 +397,7 @@ LuaDefine(deque_findr, "deque,value", "find the first occurrence of value in deq
     LuaArg deque, val;
     LuaRet pos;
     LuaVar check;
-    LuaOldStack LS(L, deque, val, pos, check);
+    LuaDefStack LS(L, deque, val, pos, check);
     int left, fill, max;
     deque_get_info(L, deque.index(), &left, &fill, &max);
     int base = left + fill - 1;
@@ -416,7 +416,7 @@ LuaDefine(deque_findr, "deque,value", "find the first occurrence of value in deq
 LuaDefine(deque_size, "deque", "return the number of items in the deque") {
     LuaArg deque;
     LuaRet size;
-    LuaOldStack LS(L, deque, size);
+    LuaDefStack LS(L, deque, size);
     LS.checktable(deque, "deque");
     LS.rawget(size, deque, DEQUE_FILL);
     LS.checknumber(size, "deque size");
@@ -537,7 +537,7 @@ static void auxsort (lua_State *L, int tab, int l, int u) {
 bool table_getpairs(LuaCoreStack &LS0, LuaSlot tab, LuaSlot pairs, bool sort) {
     lua_State *L = LS0.state();
     LuaVar key, value;
-    LuaOldStack LS(L, key, value);
+    LuaExtStack LS(L, key, value);
     bool sorted = true;
     // Create the table, store the initial 1.
     int total = lua_nkeys(L, tab.index());
@@ -558,7 +558,6 @@ bool table_getpairs(LuaCoreStack &LS0, LuaSlot tab, LuaSlot pairs, bool sort) {
     if (sort) {
         auxsort(L, pairs.index(), 1, total);
     }
-    LS.result();
     return sorted;
 }
 
@@ -602,7 +601,7 @@ LuaDefine(table_sortedpairs, "table",
     "|") {
     LuaArg tab;
     LuaRet closure, rtab, key;
-    LuaOldStack LS(L, tab, closure, rtab, key);
+    LuaDefStack LS(L, tab, closure, rtab, key);
     bool sorted = table_getpairs(LS, tab, rtab, true);
     if (!sorted) {
         luaL_error(L, "Cannot sort the table keys");
@@ -625,7 +624,7 @@ LuaDefine(table_semisortedpairs, "table",
     "|") {
     LuaArg tab;
     LuaRet closure, rtab, key;
-    LuaOldStack LS(L, tab, closure, rtab, key);
+    LuaDefStack LS(L, tab, closure, rtab, key);
     table_getpairs(LS, tab, rtab, true);
     LS.set(closure, lfn_table_nextsortedpair);
     LS.set(key, LuaNil);
@@ -665,7 +664,7 @@ LuaDefine(genlt, "obj1,obj2",
     "|") {
     LuaArg o1,o2;
     LuaRet lt;
-    LuaOldStack LS(L, o1, o2, lt);
+    LuaDefStack LS(L, o1, o2, lt);
     int ltf = lua_genlt(L, o1.index(), o2.index());
     LS.set(lt, ltf ? true:false);
     return LS.result();