diff --git a/include/lstate.h b/include/lstate.h
index 93029b4..8aacb74 100644
--- a/include/lstate.h
+++ b/include/lstate.h
@@ -1,5 +1,5 @@
 /*
-** $Id: lstate.h,v 2.128 2015/11/13 12:16:51 roberto Exp $
+** $Id: lstate.h,v 2.130 2015/12/16 16:39:38 roberto Exp $
 ** Global State
 ** See Copyright Notice in lua.h
 */
@@ -33,6 +33,15 @@
 struct lua_longjmp;  /* defined in ldo.c */
 
 
+/*
+** Atomic type (relative to signals) to better ensure that 'lua_sethook' 
+** is thread safe
+*/
+#if !defined(l_signalT)
+#include <signal.h>
+#define l_signalT	sig_atomic_t
+#endif
+
 
 /* extra stack space to handle TM calls and some other extras */
 #define EXTRA_STACK   5
@@ -171,7 +180,7 @@ struct lua_State {
   struct lua_State *twups;  /* list of threads with open upvalues */
   struct lua_longjmp *errorJmp;  /* current error recover point */
   CallInfo base_ci;  /* CallInfo for first level (C calling Lua) */
-  lua_Hook hook;
+  volatile lua_Hook hook;
   ptrdiff_t errfunc;  /* current error handling function (stack index) */
   int stacksize;
   int basehookcount;
diff --git a/include/ltests.h b/include/ltests.h
index 6aceb16..760dc73 100644
--- a/include/ltests.h
+++ b/include/ltests.h
@@ -1,5 +1,5 @@
 /*
-** $Id: ltests.h,v 2.47 2014/12/26 14:44:44 roberto Exp $
+** $Id: ltests.h,v 2.49 2015/09/22 14:18:24 roberto Exp $
 ** Internal Header for Debugging of the Lua Implementation
 ** See Copyright Notice in lua.h
 */
diff --git a/include/lua.h b/include/lua.h
index 4937f94..e02ff9f 100644
--- a/include/lua.h
+++ b/include/lua.h
@@ -1,5 +1,5 @@
 /*
-** $Id: lua.h,v 1.329 2015/11/13 17:18:42 roberto Exp $
+** $Id: lua.h,v 1.331 2016/05/30 15:53:28 roberto Exp $
 ** Lua - A Scripting Language
 ** Lua.org, PUC-Rio, Brazil (http://www.lua.org)
 ** See Copyright Notice at the end of this file
@@ -19,11 +19,11 @@
 #define LUA_VERSION_MAJOR	"5"
 #define LUA_VERSION_MINOR	"3"
 #define LUA_VERSION_NUM		503
-#define LUA_VERSION_RELEASE	"2"
+#define LUA_VERSION_RELEASE	"3"
 
 #define LUA_VERSION	"Ravi " LUA_VERSION_MAJOR "." LUA_VERSION_MINOR
 #define LUA_RELEASE	LUA_VERSION "." LUA_VERSION_RELEASE
-#define LUA_COPYRIGHT	LUA_RELEASE "\nCopyright (C) 1994-2015 Lua.org, PUC-Rio\nPortions Copyright (C) 2015 Dibyendu Majumdar"
+#define LUA_COPYRIGHT	LUA_RELEASE "\nCopyright (C) 1994-2016 Lua.org, PUC-Rio\nPortions Copyright (C) 2015-2016 Dibyendu Majumdar"
 #define LUA_AUTHORS	"R. Ierusalimschy, L. H. de Figueiredo, W. Celes, Dibyendu Majumdar"
 
 
@@ -544,7 +544,7 @@ LUA_API void ravi_set_debuglevel(int level);
 
 
 /******************************************************************************
-* Copyright (C) 1994-2015 Lua.org, PUC-Rio.
+* Copyright (C) 1994-2016 Lua.org, PUC-Rio.
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
diff --git a/include/lvm.h b/include/lvm.h
index d74b1d4..2f898a4 100644
--- a/include/lvm.h
+++ b/include/lvm.h
@@ -1,5 +1,5 @@
 /*
-** $Id: lvm.h,v 2.39 2015/09/09 13:44:07 roberto Exp $
+** $Id: lvm.h,v 2.40 2016/01/05 16:07:21 roberto Exp $
 ** Lua virtual machine
 ** See Copyright Notice in lua.h
 */
@@ -49,25 +49,24 @@
 
 
 /*
-** fast track for 'gettable': 1 means 'aux' points to resulted value;
-** 0 means 'aux' is metamethod (if 't' is a table) or NULL. 'f' is
-** the raw get function to use.
+** fast track for 'gettable': if 't' is a table and 't[k]' is not nil,
+** return 1 with 'slot' pointing to 't[k]' (final result).  Otherwise,
+** return 0 (meaning it will have to check metamethod) with 'slot'
+** pointing to a nil 't[k]' (if 't' is a table) or NULL (otherwise).
+** 'f' is the raw get function to use.
 */
-#define luaV_fastget(L,t,k,aux,f) \
+#define luaV_fastget(L,t,k,slot,f) \
   (!ttistable(t)  \
-   ? (aux = NULL, 0)  /* not a table; 'aux' is NULL and result is 0 */  \
-   : (aux = f(hvalue(t), k),  /* else, do raw access */  \
-      !ttisnil(aux) ? 1  /* result not nil? 'aux' has it */  \
-      : (aux = fasttm(L, hvalue(t)->metatable, TM_INDEX),  /* get metamethod */\
-         aux != NULL  ? 0  /* has metamethod? must call it */  \
-         : (aux = luaO_nilobject, 1))))  /* else, final result is nil */
+   ? (slot = NULL, 0)  /* not a table; 'slot' is NULL and result is 0 */  \
+   : (slot = f(hvalue(t), k),  /* else, do raw access */  \
+      !ttisnil(slot)))  /* result not nil? */
 
 /*
 ** standard implementation for 'gettable'
 */
-#define luaV_fastgettable(L,t,k,v) { const TValue *aux; \
-  if (luaV_fastget(L,t,k,aux,luaH_get)) { setobj2s(L, v, aux); } \
-  else luaV_finishget(L,t,k,v,aux); }
+#define luaV_fastgettable(L,t,k,v) { const TValue *slot; \
+  if (luaV_fastget(L,t,k,slot,luaH_get)) { setobj2s(L, v, slot); } \
+  else luaV_finishget(L,t,k,v,slot); }
 
 
 /*
@@ -105,10 +104,11 @@ LUAI_FUNC void luaV_gettable (lua_State *L, const TValue *t, TValue *key,
 LUAI_FUNC void luaV_settable (lua_State *L, const TValue *t, TValue *key,
                                             StkId val);
 LUAI_FUNC void luaV_finishget (lua_State *L, const TValue *t, TValue *key,
-                               StkId val, const TValue *tm);
+                               StkId val, const TValue *slot);
 LUAI_FUNC void luaV_finishset (lua_State *L, const TValue *t, TValue *key,
-                               StkId val, const TValue *oldval);
+                               StkId val, const TValue *slot);
 LUAI_FUNC void luaV_finishOp (lua_State *L);
+/* The int return value is a Ravi extension */
 LUAI_FUNC int luaV_execute (lua_State *L);
 LUAI_FUNC void luaV_concat (lua_State *L, int total);
 LUAI_FUNC lua_Integer luaV_div (lua_State *L, lua_Integer x, lua_Integer y);
@@ -116,7 +116,7 @@ LUAI_FUNC lua_Integer luaV_mod (lua_State *L, lua_Integer x, lua_Integer y);
 LUAI_FUNC lua_Integer luaV_shiftl (lua_Integer x, lua_Integer y);
 LUAI_FUNC void luaV_objlen (lua_State *L, StkId ra, const TValue *rb);
 
-// RAVI changes
+/* RAVI changes for JIT */
 
 LUAI_FUNC int luaV_forlimit(const TValue *obj, lua_Integer *p, lua_Integer step,
   int *stopnow);
diff --git a/src/lapi.c b/src/lapi.c
index c2b05c8..943176c 100644
--- a/src/lapi.c
+++ b/src/lapi.c
@@ -1,11 +1,11 @@
 /*
-** $Id: lapi.c,v 2.257 2015/11/02 18:48:07 roberto Exp $
+** $Id: lapi.c,v 2.259 2016/02/29 14:27:14 roberto Exp $
 ** Lua API
 ** See Copyright Notice in lua.h
 */
 
 /*
-** Portions Copyright (C) 2015 Dibyendu Majumdar
+** Portions Copyright (C) 2015-2016 Dibyendu Majumdar
 */
 
 
@@ -412,9 +412,9 @@ LUA_API const char *lua_tolstring (lua_State *L, int idx, size_t *len) {
       return NULL;
     }
     lua_lock(L);  /* 'luaO_tostring' may create a new string */
+    luaO_tostring(L, o);
     luaC_checkGC(L);
     o = index2addr(L, idx);  /* previous call may reallocate the stack */
-    luaO_tostring(L, o);
     lua_unlock(L);
   }
   if (len != NULL)
@@ -517,10 +517,10 @@ LUA_API void lua_pushinteger (lua_State *L, lua_Integer n) {
 LUA_API const char *lua_pushlstring (lua_State *L, const char *s, size_t len) {
   TString *ts;
   lua_lock(L);
-  luaC_checkGC(L);
   ts = (len == 0) ? luaS_new(L, "") : luaS_newlstr(L, s, len);
   setsvalue2s(L, L->top, ts);
   api_incr_top(L);
+  luaC_checkGC(L);
   lua_unlock(L);
   return getstr(ts);
 }
@@ -532,12 +532,12 @@ LUA_API const char *lua_pushstring (lua_State *L, const char *s) {
     setnilvalue(L->top);
   else {
     TString *ts;
-    luaC_checkGC(L);
     ts = luaS_new(L, s);
     setsvalue2s(L, L->top, ts);
     s = getstr(ts);  /* internal copy's address */
   }
   api_incr_top(L);
+  luaC_checkGC(L);
   lua_unlock(L);
   return s;
 }
@@ -547,8 +547,8 @@ LUA_API const char *lua_pushvfstring (lua_State *L, const char *fmt,
                                       va_list argp) {
   const char *ret;
   lua_lock(L);
-  luaC_checkGC(L);
   ret = luaO_pushvfstring(L, fmt, argp);
+  luaC_checkGC(L);
   lua_unlock(L);
   return ret;
 }
@@ -558,10 +558,10 @@ LUA_API const char *lua_pushfstring (lua_State *L, const char *fmt, ...) {
   const char *ret;
   va_list argp;
   lua_lock(L);
-  luaC_checkGC(L);
   va_start(argp, fmt);
   ret = luaO_pushvfstring(L, fmt, argp);
   va_end(argp);
+  luaC_checkGC(L);
   lua_unlock(L);
   return ret;
 }
@@ -578,7 +578,6 @@ LUA_API void lua_pushcclosure (lua_State *L, lua_CFunction fn, int n) {
     if (n > MAXUPVAL)
       luaG_runerror(L, "upvalue index too large");
     api_check(L, n <= MAXUPVAL, "upvalue index too large");
-    luaC_checkGC(L);
     cl = luaF_newCclosure(L, n);
     cl->f = fn;
     L->top -= n;
@@ -589,6 +588,7 @@ LUA_API void lua_pushcclosure (lua_State *L, lua_CFunction fn, int n) {
     setclCvalue(L, L->top, cl);
   }
   api_incr_top(L);
+  luaC_checkGC(L);
   lua_unlock(L);
 }
 
@@ -625,16 +625,16 @@ LUA_API int lua_pushthread (lua_State *L) {
 
 
 static int auxgetstr (lua_State *L, const TValue *t, const char *k) {
-  const TValue *aux;
+  const TValue *slot;
   TString *str = luaS_new(L, k);
-  if (luaV_fastget(L, t, str, aux, luaH_getstr)) {
-    setobj2s(L, L->top, aux);
+  if (luaV_fastget(L, t, str, slot, luaH_getstr)) {
+    setobj2s(L, L->top, slot);
     api_incr_top(L);
   }
   else {
     setsvalue2s(L, L->top, str);
     api_incr_top(L);
-    luaV_finishget(L, t, L->top - 1, L->top - 1, aux);
+    luaV_finishget(L, t, L->top - 1, L->top - 1, slot);
   }
   lua_unlock(L);
   return ttnov(L->top - 1);
@@ -663,20 +663,21 @@ LUA_API int lua_getfield (lua_State *L, int idx, const char *k) {
   return auxgetstr(L, index2addr(L, idx), k);
 }
 
-LUA_API int lua_geti(lua_State *L, int idx, lua_Integer n) {
+
+LUA_API int lua_geti (lua_State *L, int idx, lua_Integer n) {
   StkId t;
-  const TValue *aux;
+  const TValue *slot;
   lua_lock(L);
   t = index2addr(L, idx);
   if (!ttistable(t) || hvalue(t)->ravi_array.array_type == RAVI_TTABLE) {
-    if (luaV_fastget(L, t, n, aux, luaH_getint)) {
-      setobj2s(L, L->top, aux);
+    if (luaV_fastget(L, t, n, slot, luaH_getint)) {
+      setobj2s(L, L->top, slot);
       api_incr_top(L);
     }
     else {
       setivalue(L->top, n);
       api_incr_top(L);
-      luaV_finishget(L, t, L->top - 1, L->top - 1, aux);
+      luaV_finishget(L, t, L->top - 1, L->top - 1, slot);
     }
   }
   else {
@@ -741,7 +742,8 @@ LUA_API int lua_rawget(lua_State *L, int idx) {
   return ttnov(L->top - 1);
 }
 
-LUA_API int lua_rawgeti(lua_State *L, int idx, lua_Integer n) {
+
+LUA_API int lua_rawgeti (lua_State *L, int idx, lua_Integer n) {
   StkId t;
   Table *h;
   lua_lock(L);
@@ -768,6 +770,7 @@ LUA_API int lua_rawgeti(lua_State *L, int idx, lua_Integer n) {
   return ttnov(L->top - 1);
 }
 
+
 LUA_API int lua_rawgetp (lua_State *L, int idx, const void *p) {
   StkId t;
   TValue k;
@@ -788,12 +791,12 @@ LUA_API int lua_rawgetp (lua_State *L, int idx, const void *p) {
 LUA_API void lua_createtable (lua_State *L, int narray, int nrec) {
   Table *t;
   lua_lock(L);
-  luaC_checkGC(L);
   t = luaH_new(L);
   sethvalue(L, L->top, t);
   api_incr_top(L);
   if (narray > 0 || nrec > 0)
     luaH_resize(L, t, narray, nrec);
+  luaC_checkGC(L);
   lua_unlock(L);
 }
 
@@ -804,10 +807,10 @@ LUA_API void ravi_create_integer_array(lua_State *L, int narray,
                                      lua_Integer initial_value) {
   Table *t;
   lua_lock(L);
-  luaC_checkGC(L);
   t = raviH_new_integer_array(L, (unsigned int)narray, initial_value);
   sethvalue(L, L->top, t);
   api_incr_top(L);
+  luaC_checkGC(L);
   lua_unlock(L);
 }
 
@@ -818,10 +821,10 @@ LUA_API void ravi_create_number_array(lua_State *L, int narray,
                                     lua_Number initial_value) {
   Table *t;
   lua_lock(L);
-  luaC_checkGC(L);
   t = raviH_new_number_array(L, (unsigned int)narray, initial_value);
   sethvalue(L, L->top, t);
   api_incr_top(L);
+  luaC_checkGC(L);
   lua_unlock(L);
 }
 
@@ -872,7 +875,6 @@ LUA_API void ravi_create_slice(lua_State *L, int idx, unsigned int start,
   Table *slice;
   const char *errmsg = NULL;
   lua_lock(L);
-  luaC_checkGC(L);
   /* The do-while loop here is just for error handling */
   parent = index2addr(L, idx);
   if (!ttistable(parent)) {
@@ -891,6 +893,7 @@ LUA_API void ravi_create_slice(lua_State *L, int idx, unsigned int start,
   slice = raviH_new_slice(L, parent, start, len);
   sethvalue(L, L->top, slice);
   api_incr_top(L);
+  luaC_checkGC(L);
 done:
   lua_unlock(L);
   if (errmsg)
@@ -944,15 +947,15 @@ LUA_API int lua_getuservalue (lua_State *L, int idx) {
 ** t[k] = value at the top of the stack (where 'k' is a string)
 */
 static void auxsetstr (lua_State *L, const TValue *t, const char *k) {
-  const TValue *aux;
+  const TValue *slot;
   TString *str = luaS_new(L, k);
   api_checknelems(L, 1);
-  if (luaV_fastset(L, t, str, aux, luaH_getstr, L->top - 1))
+  if (luaV_fastset(L, t, str, slot, luaH_getstr, L->top - 1))
     L->top--;  /* pop value */
   else {
     setsvalue2s(L, L->top, str);  /* push 'str' (to make it a TValue) */
     api_incr_top(L);
-    luaV_finishset(L, t, L->top - 1, L->top - 2, aux);
+    luaV_finishset(L, t, L->top - 1, L->top - 2, slot);
     L->top -= 2;  /* pop value and key */
   }
   lua_unlock(L);  /* lock done by caller */
@@ -984,17 +987,17 @@ LUA_API void lua_setfield (lua_State *L, int idx, const char *k) {
 
 LUA_API void lua_seti(lua_State *L, int idx, lua_Integer n) {
   StkId t;
-  const TValue *aux;
+  const TValue *slot;
   lua_lock(L);
   api_checknelems(L, 1);
   t = index2addr(L, idx);
   if (!ttistable(t) || hvalue(t)->ravi_array.array_type == RAVI_TTABLE) {
-    if (luaV_fastset(L, t, n, aux, luaH_getint, L->top - 1))
+    if (luaV_fastset(L, t, n, slot, luaH_getint, L->top - 1))
       L->top--; /* pop value */
     else {
       setivalue(L->top, n);
       api_incr_top(L);
-      luaV_finishset(L, t, L->top - 1, L->top - 2, aux);
+      luaV_finishset(L, t, L->top - 1, L->top - 2, slot);
       L->top -= 2; /* pop value and key */
     }
   }
@@ -1030,6 +1033,7 @@ LUA_API void lua_seti(lua_State *L, int idx, lua_Integer n) {
 
 LUA_API void lua_rawset(lua_State *L, int idx) {
   StkId o;
+  TValue *slot;
   Table *t;
   lua_lock(L);
   api_checknelems(L, 2);
@@ -1037,7 +1041,8 @@ LUA_API void lua_rawset(lua_State *L, int idx) {
   api_check(L, ttistable(o), "table expected");
   t = hvalue(o);
   if (t->ravi_array.array_type == RAVI_TTABLE) {
-    setobj2t(L, luaH_set(L, t, L->top - 2), L->top - 1);
+    slot = luaH_set(L, t, L->top - 2);
+    setobj2t(L, slot, L->top - 1);
     invalidateTMcache(t);
     luaC_barrierback(L, t, L->top - 1);
   }
@@ -1122,7 +1127,7 @@ LUA_API void lua_rawseti(lua_State *L, int idx, lua_Integer n) {
 LUA_API void lua_rawsetp (lua_State *L, int idx, const void *p) {
   StkId o;
   Table *t;
-  TValue k;
+  TValue k, *slot;
   lua_lock(L);
   api_checknelems(L, 1);
   o = index2addr(L, idx);
@@ -1130,7 +1135,8 @@ LUA_API void lua_rawsetp (lua_State *L, int idx, const void *p) {
   t = hvalue(o);
   api_check(L, t->ravi_array.array_type == RAVI_TTABLE, "Lua table expected");
   setpvalue(&k, cast(void *, p));
-  setobj2t(L, luaH_set(L, t, &k), L->top - 1);
+  slot = luaH_set(L, t, &k);
+  setobj2t(L, slot, L->top - 1);
   luaC_barrierback(L, t, L->top - 1);
   L->top--;
   lua_unlock(L);
@@ -1437,7 +1443,6 @@ LUA_API void lua_concat (lua_State *L, int n) {
   lua_lock(L);
   api_checknelems(L, n);
   if (n >= 2) {
-    luaC_checkGC(L);
     luaV_concat(L, n);
   }
   else if (n == 0) {  /* push empty string */
@@ -1445,6 +1450,7 @@ LUA_API void lua_concat (lua_State *L, int n) {
     api_incr_top(L);
   }
   /* else n == 1; nothing to do */
+  luaC_checkGC(L);
   lua_unlock(L);
 }
 
@@ -1480,10 +1486,10 @@ LUA_API void lua_setallocf (lua_State *L, lua_Alloc f, void *ud) {
 LUA_API void *lua_newuserdata (lua_State *L, size_t size) {
   Udata *u;
   lua_lock(L);
-  luaC_checkGC(L);
   u = luaS_newudata(L, size);
   setuvalue(L, L->top, u);
   api_incr_top(L);
+  luaC_checkGC(L);
   lua_unlock(L);
   return getudatamem(u);
 }
diff --git a/src/lauxlib.c b/src/lauxlib.c
index b1de175..b9427f5 100644
--- a/src/lauxlib.c
+++ b/src/lauxlib.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lauxlib.c,v 1.284 2015/11/19 19:16:22 roberto Exp $
+** $Id: lauxlib.c,v 1.286 2016/01/08 15:33:09 roberto Exp $
 ** Auxiliary functions for building Lua libraries
 ** See Copyright Notice in lua.h
 */
@@ -17,7 +17,8 @@
 #include <string.h>
 
 
-/* This file uses only the official API of Lua.
+/*
+** This file uses only the official API of Lua.
 ** Any function declared here could be written as an application function.
 */
 
@@ -198,6 +199,10 @@ static void tag_error (lua_State *L, int arg, int tag) {
 }
 
 
+/*
+** The use of 'lua_pushfstring' ensures this function does not
+** need reserved stack space when called.
+*/
 LUALIB_API void luaL_where (lua_State *L, int level) {
   lua_Debug ar;
   if (lua_getstack(L, level, &ar)) {  /* check function at level */
@@ -207,10 +212,15 @@ LUALIB_API void luaL_where (lua_State *L, int level) {
       return;
     }
   }
-  lua_pushliteral(L, "");  /* else, no information available... */
+  lua_pushfstring(L, "");  /* else, no information available... */
 }
 
 
+/*
+** Again, the use of 'lua_pushvfstring' ensures this function does
+** not need reserved stack space when called. (At worst, it generates
+** an error with "stack overflow" instead of the given message.)
+*/
 LUALIB_API int luaL_error (lua_State *L, const char *fmt, ...) {
   va_list argp;
   va_start(argp, fmt);
@@ -349,10 +359,15 @@ LUALIB_API int luaL_checkoption (lua_State *L, int arg, const char *def,
 }
 
 
+/*
+** Ensures the stack has at least 'space' extra slots, raising an error
+** if it cannot fulfill the request. (The error handling needs a few
+** extra slots to format the error message. In case of an error without
+** this extra space, Lua will generate the same 'stack overflow' error,
+** but without 'msg'.)
+*/
 LUALIB_API void luaL_checkstack (lua_State *L, int space, const char *msg) {
-  /* keep some extra space to run error routines, if needed */
-  const int extra = LUA_MINSTACK;
-  if (!lua_checkstack(L, space + extra)) {
+  if (!lua_checkstack(L, space)) {
     if (msg)
       luaL_error(L, "stack overflow (%s)", msg);
     else
@@ -678,7 +693,7 @@ static int skipcomment (LoadF *lf, int *cp) {
   if (c == '#') {  /* first line is a comment (Unix exec. file)? */
     do {  /* skip first line */
       c = getc(lf->f);
-    } while (c != EOF && c != '\n') ;
+    } while (c != EOF && c != '\n');
     *cp = getc(lf->f);  /* skip end-of-line, if present */
     return 1;  /* there was a comment */
   }
diff --git a/src/lbaselib.c b/src/lbaselib.c
index 93450bf..4f59788 100644
--- a/src/lbaselib.c
+++ b/src/lbaselib.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lbaselib.c,v 1.312 2015/10/29 15:21:04 roberto Exp $
+** $Id: lbaselib.c,v 1.313 2016/04/11 19:18:40 roberto Exp $
 ** Basic library
 ** See Copyright Notice in lua.h
 */
@@ -102,8 +102,8 @@ static int luaB_tonumber (lua_State *L) {
 static int luaB_error (lua_State *L) {
   int level = (int)luaL_optinteger(L, 2, 1);
   lua_settop(L, 1);
-  if (lua_isstring(L, 1) && level > 0) {  /* add extra information? */
-    luaL_where(L, level);
+  if (lua_type(L, 1) == LUA_TSTRING && level > 0) {
+    luaL_where(L, level);   /* add extra information */
     lua_pushvalue(L, 1);
     lua_concat(L, 2);
   }
diff --git a/src/lcorolib.c b/src/lcorolib.c
index 0c0b7fa..2303429 100644
--- a/src/lcorolib.c
+++ b/src/lcorolib.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lcorolib.c,v 1.9 2014/11/02 19:19:04 roberto Exp $
+** $Id: lcorolib.c,v 1.10 2016/04/11 19:19:55 roberto Exp $
 ** Coroutine Library
 ** See Copyright Notice in lua.h
 */
@@ -75,7 +75,7 @@ static int luaB_auxwrap (lua_State *L) {
   lua_State *co = lua_tothread(L, lua_upvalueindex(1));
   int r = auxresume(L, co, lua_gettop(L));
   if (r < 0) {
-    if (lua_isstring(L, -1)) {  /* error object is a string? */
+    if (lua_type(L, -1) == LUA_TSTRING) {  /* error object is a string? */
       luaL_where(L, 1);  /* add extra info */
       lua_insert(L, -2);
       lua_concat(L, 2);
diff --git a/src/ldebug.c b/src/ldebug.c
index c751712..18ea101 100644
--- a/src/ldebug.c
+++ b/src/ldebug.c
@@ -1,5 +1,5 @@
 /*
-** $Id: ldebug.c,v 2.117 2015/11/02 18:48:07 roberto Exp $
+** $Id: ldebug.c,v 2.120 2016/03/31 19:01:21 roberto Exp $
 ** Debug Interface
 ** See Copyright Notice in lua.h
 */
diff --git a/src/ldo.c b/src/ldo.c
index b6e91f8..169b6ba 100644
--- a/src/ldo.c
+++ b/src/ldo.c
@@ -1,5 +1,5 @@
 /*
-** $Id: ldo.c,v 2.150 2015/11/19 19:16:22 roberto Exp $
+** $Id: ldo.c,v 2.151 2015/12/16 16:40:07 roberto Exp $
 ** Stack and Call structure of Lua
 ** See Copyright Notice in lua.h
 */
diff --git a/src/lvm.c b/src/lvm.c
index c620f37..10b6d05 100644
--- a/src/lvm.c
+++ b/src/lvm.c
@@ -1,11 +1,11 @@
 /*
-** $Id: lvm.c,v 2.265 2015/11/23 11:30:45 roberto Exp $
+** $Id: lvm.c,v 2.268 2016/02/05 19:59:14 roberto Exp $
 ** Lua virtual machine
 ** See Copyright Notice in lua.h
 */
 
 /*
-** Portions Copyright (C) 2015 Dibyendu Majumdar
+** Portions Copyright (C) 2015-2016 Dibyendu Majumdar
 */
 
 
@@ -166,55 +166,67 @@ int luaV_forlimit (const TValue *obj, lua_Integer *p, lua_Integer step,
 
 
 /*
-** Complete a table access: if 't' is a table, 'tm' has its metamethod;
-** otherwise, 'tm' is NULL.
+** Finish the table access 'val = t[key]'.
+** if 'slot' is NULL, 't' is not a table; otherwise, 'slot' points to
+** t[k] entry (which must be nil).
 */
 void luaV_finishget (lua_State *L, const TValue *t, TValue *key, StkId val,
-                      const TValue *tm) {
+                      const TValue *slot) {
   int loop;  /* counter to avoid infinite loops */
-  lua_assert(tm != NULL || !ttistable(t));
+  const TValue *tm;  /* metamethod */
   for (loop = 0; loop < MAXTAGLOOP; loop++) {
-    if (tm == NULL) {  /* no metamethod (from a table)? */
-      if (ttisnil(tm = luaT_gettmbyobj(L, t, TM_INDEX)))
+    if (slot == NULL) {  /* 't' is not a table? */
+      lua_assert(!ttistable(t));
+      tm = luaT_gettmbyobj(L, t, TM_INDEX);
+      if (ttisnil(tm))
         luaG_typeerror(L, t, "index");  /* no metamethod */
+      /* else will try the metamethod */
+    }
+    else {  /* 't' is a table */
+      lua_assert(ttisnil(slot));
+      tm = fasttm(L, hvalue(t)->metatable, TM_INDEX);  /* table's metamethod */
+      if (tm == NULL) {  /* no metamethod? */
+        setnilvalue(val);  /* result is nil */
+        return;
+      }
+      /* else will try the metamethod */
     }
-    if (ttisfunction(tm)) {  /* metamethod is a function */
+    if (ttisfunction(tm)) {  /* is metamethod a function? */
       luaT_callTM(L, tm, t, key, val, 1);  /* call it */
       return;
     }
-    t = tm;  /* else repeat access over 'tm' */
-    if (luaV_fastget(L,t,key,tm,luaH_get)) {  /* try fast track */
-      setobj2s(L, val, tm);  /* done */
+    t = tm;  /* else try to access 'tm[key]' */
+    if (luaV_fastget(L,t,key,slot,luaH_get)) {  /* fast track? */
+      setobj2s(L, val, slot);  /* done */
       return;
     }
-    /* else repeat */
+    /* else repeat (tail call 'luaV_finishget') */
   }
-  luaG_runerror(L, "gettable chain too long; possible loop");
+  luaG_runerror(L, "'__index' chain too long; possible loop");
 }
 
 
 /*
-** Main function for table assignment (invoking metamethods if needed).
-** Compute 't[key] = val'
+** Finish a table assignment 't[key] = val'.
+** If 'slot' is NULL, 't' is not a table.  Otherwise, 'slot' points
+** to the entry 't[key]', or to 'luaO_nilobject' if there is no such
+** entry.  (The value at 'slot' must be nil, otherwise 'luaV_fastset'
+** would have done the job.)
 */
 void luaV_finishset (lua_State *L, const TValue *t, TValue *key,
-                     StkId val, const TValue *oldval) {
+                     StkId val, const TValue *slot) {
   int loop;  /* counter to avoid infinite loops */
   for (loop = 0; loop < MAXTAGLOOP; loop++) {
-    const TValue *tm;
-    if (oldval != NULL) {
-      lua_assert(ttistable(t) && ttisnil(oldval));
+    const TValue *tm;  /* '__newindex' metamethod */
+    if (slot != NULL) {  /* is 't' a table? */
       Table *h = hvalue(t);  /* save 't' table */
-      lua_assert(ttisnil(oldval));
-      /* must check the metamethod */
-      if ((tm = fasttm(L, h->metatable, TM_NEWINDEX)) == NULL &&
-         /* no metamethod; is there a previous entry in the table? */
-         (oldval != luaO_nilobject ||
-         /* no previous entry; must create one. (The next test is
-            always true; we only need the assignment.) */
-         (oldval = luaH_newkey(L, h, key), 1))) {
+      lua_assert(ttisnil(slot));  /* old value must be nil */
+      tm = fasttm(L, h->metatable, TM_NEWINDEX);  /* get metamethod */
+      if (tm == NULL) {  /* no metamethod? */
+        if (slot == luaO_nilobject)  /* no previous entry? */
+          slot = luaH_newkey(L, h, key);  /* create one */
         /* no metamethod and (now) there is an entry with given key */
-        setobj2t(L, cast(TValue *, oldval), val);
+        setobj2t(L, cast(TValue *, slot), val);  /* set its new value */
         invalidateTMcache(h);
         luaC_barrierback(L, h, val);
         return;
@@ -231,7 +243,7 @@ void luaV_finishset (lua_State *L, const TValue *t, TValue *key,
       return;
     }
     t = tm;  /* else repeat assignment over 'tm' */
-    if (luaV_fastset(L, t, key, oldval, luaH_get, val))
+    if (luaV_fastset(L, t, key, slot, luaH_get, val))
       return;  /* done */
     /* else loop */
   }
@@ -854,12 +866,12 @@ void luaV_finishOp (lua_State *L) {
 
 
 /*
-** copy of 'luaV_gettable', but protecting call to potential metamethod
-** (which can reallocate the stack)
+** copy of 'luaV_gettable', but protecting the call to potential
+** metamethod (which can reallocate the stack)
 */
-#define gettableProtected(L,t,k,v)  { const TValue *aux; \
-  if (luaV_fastget(L,t,k,aux,luaH_get)) { setobj2s(L, v, aux); } \
-  else Protect(luaV_finishget(L,t,k,v,aux)); }
+#define gettableProtected(L,t,k,v)  { const TValue *slot; \
+  if (luaV_fastget(L,t,k,slot,luaH_get)) { setobj2s(L, v, slot); } \
+  else Protect(luaV_finishget(L,t,k,v,slot)); }
 
 
 /* same for 'luaV_settable' */