From 3237c6de1490473954d58065138ed4a4204cd973 Mon Sep 17 00:00:00 2001
From: Andrew Pamment <apamment@yandex.com>
Date: Sat, 10 Dec 2016 07:31:44 +1000
Subject: [PATCH] Update LUA

---
 lua/Makefile   |   7 +-
 lua/lapi.c     |  48 ++--
 lua/lauxlib.c  |  29 ++-
 lua/lbaselib.c |  11 +-
 lua/lcode.c    | 694 +++++++++++++++++++++++++++++++++----------------
 lua/lcode.h    |   5 +-
 lua/lcorolib.c |   4 +-
 lua/ldebug.c   |  18 +-
 lua/ldo.c      |   9 +-
 lua/ldo.h      |   4 +-
 lua/lgc.c      |  35 +--
 lua/lgc.h      |   4 +-
 lua/liolib.c   |  19 +-
 lua/llex.c     |  35 +--
 lua/llex.h     |   3 +-
 lua/lobject.c  |  88 +++++--
 lua/loslib.c   |  91 ++++---
 lua/lparser.c  |  40 +--
 lua/lparser.h  |  53 ++--
 lua/lstate.h   |  15 +-
 lua/lstrlib.c  | 143 ++++++----
 lua/ltablib.c  |  41 +--
 lua/ltm.c      |  18 +-
 lua/ltm.h      |   5 +-
 lua/lua.h      |  10 +-
 lua/luaconf.h  |   4 +-
 lua/lvm.c      | 105 +++++---
 lua/lvm.h      |  31 ++-
 28 files changed, 975 insertions(+), 594 deletions(-)

diff --git a/lua/Makefile b/lua/Makefile
index 79f5ce8..d71c75c 100644
--- a/lua/Makefile
+++ b/lua/Makefile
@@ -26,7 +26,7 @@ MYOBJS=
 
 # == END OF USER SETTINGS -- NO NEED TO CHANGE ANYTHING BELOW THIS LINE =======
 
-PLATS= aix bsd c89 freebsd generic linux macosx mingw posix solaris minix
+PLATS= aix bsd c89 freebsd generic linux macosx mingw posix solaris
 
 LUA_A=	liblua.a
 CORE_O=	lapi.o lcode.o lctype.o ldebug.o ldo.o ldump.o lfunc.o lgc.o llex.o \
@@ -101,11 +101,8 @@ c89:
 	@echo ''
 
 
-minix:
-	$(MAKE) $(ALL) CC="clang" SYSCFLAGS="-DLUA_USE_LINUX" SYSLIBS="-L/usr/pkg/lib -Wl,-E -lreadline"
-
 freebsd:
-	$(MAKE) $(ALL) CC="cc" SYSCFLAGS="-DLUA_USE_LINUX -I/usr/local/include" SYSLIBS="-Wl,-E -L/usr/local/lib -lreadline"
+	$(MAKE) $(ALL) SYSCFLAGS="-DLUA_USE_LINUX" SYSLIBS="-Wl,-E -lreadline"
 
 generic: $(ALL)
 
diff --git a/lua/lapi.c b/lua/lapi.c
index 9a6a3fb..c9455a5 100644
--- a/lua/lapi.c
+++ b/lua/lapi.c
@@ -1,5 +1,5 @@
 /*
-** $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
 */
@@ -378,9 +378,9 @@ 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)
@@ -479,10 +479,10 @@ 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);
 }
@@ -494,12 +494,12 @@ 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;
 }
@@ -509,8 +509,8 @@ 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;
 }
@@ -520,10 +520,10 @@ 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;
 }
@@ -538,7 +538,6 @@ LUA_API void lua_pushcclosure (lua_State *L, lua_CFunction fn, int n) {
     CClosure *cl;
     api_checknelems(L, n);
     api_check(L, n <= MAXUPVAL, "upvalue index too large");
-    luaC_checkGC(L);
     cl = luaF_newCclosure(L, n);
     cl->f = fn;
     L->top -= n;
@@ -549,6 +548,7 @@ 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);
 }
 
@@ -585,16 +585,16 @@ 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);
@@ -626,17 +626,17 @@ LUA_API int lua_getfield (lua_State *L, int idx, const char *k) {
 
 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 (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);
   }
   lua_unlock(L);
   return ttnov(L->top - 1);
@@ -683,12 +683,12 @@ 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);
 }
 
@@ -740,15 +740,15 @@ 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 */
@@ -781,16 +781,16 @@ 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 (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 */
   }
   lua_unlock(L);
@@ -1140,7 +1140,6 @@ 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 */
@@ -1148,6 +1147,7 @@ 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);
 }
 
@@ -1183,10 +1183,10 @@ 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/lua/lauxlib.c b/lua/lauxlib.c
index 5d362c3..bacf43b 100644
--- a/lua/lauxlib.c
+++ b/lua/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/lua/lbaselib.c b/lua/lbaselib.c
index 861823d..d481c4e 100644
--- a/lua/lbaselib.c
+++ b/lua/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);
   }
@@ -251,9 +251,8 @@ static int ipairsaux (lua_State *L) {
 
 
 /*
-** This function will use either 'ipairsaux' or 'ipairsaux_raw' to
-** traverse a table, depending on whether the table has metamethods
-** that can affect the traversal.
+** 'ipairs' function. Returns 'ipairsaux', given "table", 0.
+** (The given "table" may not be a table.)
 */
 static int luaB_ipairs (lua_State *L) {
 #if defined(LUA_COMPAT_IPAIRS)
diff --git a/lua/lcode.c b/lua/lcode.c
index 7c6918f..2cd0dd2 100644
--- a/lua/lcode.c
+++ b/lua/lcode.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lcode.c,v 2.103 2015/11/19 19:16:22 roberto Exp $
+** $Id: lcode.c,v 2.109 2016/05/13 19:09:21 roberto Exp $
 ** Code generator for Lua
 ** See Copyright Notice in lua.h
 */
@@ -36,6 +36,10 @@
 #define hasjumps(e)	((e)->t != (e)->f)
 
 
+/*
+** If expression is a numeric constant, fills 'v' with its value
+** and returns 1. Otherwise, returns 0.
+*/
 static int tonumeral(expdesc *e, TValue *v) {
   if (hasjumps(e))
     return 0;  /* not a numeral */
@@ -51,13 +55,19 @@ static int tonumeral(expdesc *e, TValue *v) {
 }
 
 
+/*
+** Create a OP_LOADNIL instruction, but try to optimize: if the previous
+** instruction is also OP_LOADNIL and ranges are compatible, adjust
+** range of previous instruction instead of emitting a new one. (For
+** instance, 'local a; local b' will generate a single opcode.)
+*/
 void luaK_nil (FuncState *fs, int from, int n) {
   Instruction *previous;
   int l = from + n - 1;  /* last register to set nil */
   if (fs->pc > fs->lasttarget) {  /* no jumps to current position? */
     previous = &fs->f->code[fs->pc-1];
-    if (GET_OPCODE(*previous) == OP_LOADNIL) {
-      int pfrom = GETARG_A(*previous);
+    if (GET_OPCODE(*previous) == OP_LOADNIL) {  /* previous is LOADNIL? */
+      int pfrom = GETARG_A(*previous);  /* get previous range */
       int pl = pfrom + GETARG_B(*previous);
       if ((pfrom <= from && from <= pl + 1) ||
           (from <= pfrom && pfrom <= l + 1)) {  /* can connect both? */
@@ -73,37 +83,84 @@ void luaK_nil (FuncState *fs, int from, int n) {
 }
 
 
+/*
+** Gets the destination address of a jump instruction. Used to traverse
+** a list of jumps.
+*/ 
+static int getjump (FuncState *fs, int pc) {
+  int offset = GETARG_sBx(fs->f->code[pc]);
+  if (offset == NO_JUMP)  /* point to itself represents end of list */
+    return NO_JUMP;  /* end of list */
+  else
+    return (pc+1)+offset;  /* turn offset into absolute position */
+}
+
+
+/*
+** Fix jump instruction at position 'pc' to jump to 'dest'.
+** (Jump addresses are relative in Lua)
+*/
+static void fixjump (FuncState *fs, int pc, int dest) {
+  Instruction *jmp = &fs->f->code[pc];
+  int offset = dest - (pc + 1);
+  lua_assert(dest != NO_JUMP);
+  if (abs(offset) > MAXARG_sBx)
+    luaX_syntaxerror(fs->ls, "control structure too long");
+  SETARG_sBx(*jmp, offset);
+}
+
+
+/*
+** Concatenate jump-list 'l2' into jump-list 'l1'
+*/
+void luaK_concat (FuncState *fs, int *l1, int l2) {
+  if (l2 == NO_JUMP) return;  /* nothing to concatenate? */
+  else if (*l1 == NO_JUMP)  /* no original list? */
+    *l1 = l2;  /* 'l1' points to 'l2' */
+  else {
+    int list = *l1;
+    int next;
+    while ((next = getjump(fs, list)) != NO_JUMP)  /* find last element */
+      list = next;
+    fixjump(fs, list, l2);  /* last element links to 'l2' */
+  }
+}
+
+
+/*
+** Create a jump instruction and return its position, so its destination
+** can be fixed later (with 'fixjump'). If there are jumps to
+** this position (kept in 'jpc'), link them all together so that
+** 'patchlistaux' will fix all them directly to the final destination.
+*/
 int luaK_jump (FuncState *fs) {
   int jpc = fs->jpc;  /* save list of jumps to here */
   int j;
-  fs->jpc = NO_JUMP;
+  fs->jpc = NO_JUMP;  /* no more jumps to here */
   j = luaK_codeAsBx(fs, OP_JMP, 0, NO_JUMP);
   luaK_concat(fs, &j, jpc);  /* keep them on hold */
   return j;
 }
 
 
+/*
+** Code a 'return' instruction
+*/
 void luaK_ret (FuncState *fs, int first, int nret) {
   luaK_codeABC(fs, OP_RETURN, first, nret+1, 0);
 }
 
 
+/*
+** Code a "conditional jump", that is, a test or comparison opcode
+** followed by a jump. Return jump position.
+*/
 static int condjump (FuncState *fs, OpCode op, int A, int B, int C) {
   luaK_codeABC(fs, op, A, B, C);
   return luaK_jump(fs);
 }
 
 
-static void fixjump (FuncState *fs, int pc, int dest) {
-  Instruction *jmp = &fs->f->code[pc];
-  int offset = dest-(pc+1);
-  lua_assert(dest != NO_JUMP);
-  if (abs(offset) > MAXARG_sBx)
-    luaX_syntaxerror(fs->ls, "control structure too long");
-  SETARG_sBx(*jmp, offset);
-}
-
-
 /*
 ** returns current 'pc' and marks it as a jump target (to avoid wrong
 ** optimizations with consecutive instructions not in the same basic block).
@@ -114,15 +171,11 @@ int luaK_getlabel (FuncState *fs) {
 }
 
 
-static int getjump (FuncState *fs, int pc) {
-  int offset = GETARG_sBx(fs->f->code[pc]);
-  if (offset == NO_JUMP)  /* point to itself represents end of list */
-    return NO_JUMP;  /* end of list */
-  else
-    return (pc+1)+offset;  /* turn offset into absolute position */
-}
-
-
+/*
+** Returns the position of the instruction "controlling" a given
+** jump (that is, its condition), or the jump itself if it is
+** unconditional.
+*/
 static Instruction *getjumpcontrol (FuncState *fs, int pc) {
   Instruction *pi = &fs->f->code[pc];
   if (pc >= 1 && testTMode(GET_OPCODE(*(pi-1))))
@@ -133,37 +186,41 @@ static Instruction *getjumpcontrol (FuncState *fs, int pc) {
 
 
 /*
-** check whether list has any jump that do not produce a value
-** (or produce an inverted value)
+** Patch destination register for a TESTSET instruction.
+** If instruction in position 'node' is not a TESTSET, return 0 ("fails").
+** Otherwise, if 'reg' is not 'NO_REG', set it as the destination
+** register. Otherwise, change instruction to a simple 'TEST' (produces
+** no register value)
 */
-static int need_value (FuncState *fs, int list) {
-  for (; list != NO_JUMP; list = getjump(fs, list)) {
-    Instruction i = *getjumpcontrol(fs, list);
-    if (GET_OPCODE(i) != OP_TESTSET) return 1;
-  }
-  return 0;  /* not found */
-}
-
-
 static int patchtestreg (FuncState *fs, int node, int reg) {
   Instruction *i = getjumpcontrol(fs, node);
   if (GET_OPCODE(*i) != OP_TESTSET)
     return 0;  /* cannot patch other instructions */
   if (reg != NO_REG && reg != GETARG_B(*i))
     SETARG_A(*i, reg);
-  else  /* no register to put value or register already has the value */
+  else {
+     /* no register to put value or register already has the value;
+        change instruction to simple test */
     *i = CREATE_ABC(OP_TEST, GETARG_B(*i), 0, GETARG_C(*i));
-
+  }
   return 1;
 }
 
 
+/*
+** Traverse a list of tests ensuring no one produces a value
+*/
 static void removevalues (FuncState *fs, int list) {
   for (; list != NO_JUMP; list = getjump(fs, list))
       patchtestreg(fs, list, NO_REG);
 }
 
 
+/*
+** Traverse a list of tests, patching their destination address and
+** registers: tests producing values jump to 'vtarget' (and put their
+** values in 'reg'), other tests jump to 'dtarget'.
+*/
 static void patchlistaux (FuncState *fs, int list, int vtarget, int reg,
                           int dtarget) {
   while (list != NO_JUMP) {
@@ -177,15 +234,35 @@ static void patchlistaux (FuncState *fs, int list, int vtarget, int reg,
 }
 
 
+/*
+** Ensure all pending jumps to current position are fixed (jumping
+** to current position with no values) and reset list of pending
+** jumps
+*/
 static void dischargejpc (FuncState *fs) {
   patchlistaux(fs, fs->jpc, fs->pc, NO_REG, fs->pc);
   fs->jpc = NO_JUMP;
 }
 
 
+/*
+** Add elements in 'list' to list of pending jumps to "here"
+** (current position)
+*/
+void luaK_patchtohere (FuncState *fs, int list) {
+  luaK_getlabel(fs);  /* mark "here" as a jump target */
+  luaK_concat(fs, &fs->jpc, list);
+}
+
+
+/*
+** Path all jumps in 'list' to jump to 'target'.
+** (The assert means that we cannot fix a jump to a forward address
+** because we only know addresses once code is generated.)
+*/
 void luaK_patchlist (FuncState *fs, int list, int target) {
-  if (target == fs->pc)
-    luaK_patchtohere(fs, list);
+  if (target == fs->pc)  /* 'target' is current position? */
+    luaK_patchtohere(fs, list);  /* add list to pending jumps */
   else {
     lua_assert(target < fs->pc);
     patchlistaux(fs, list, target, NO_REG, target);
@@ -193,39 +270,26 @@ void luaK_patchlist (FuncState *fs, int list, int target) {
 }
 
 
+/*
+** Path all jumps in 'list' to close upvalues up to given 'level'
+** (The assertion checks that jumps either were closing nothing
+** or were closing higher levels, from inner blocks.)
+*/
 void luaK_patchclose (FuncState *fs, int list, int level) {
   level++;  /* argument is +1 to reserve 0 as non-op */
-  while (list != NO_JUMP) {
-    int next = getjump(fs, list);
+  for (; list != NO_JUMP; list = getjump(fs, list)) {
     lua_assert(GET_OPCODE(fs->f->code[list]) == OP_JMP &&
                 (GETARG_A(fs->f->code[list]) == 0 ||
                  GETARG_A(fs->f->code[list]) >= level));
     SETARG_A(fs->f->code[list], level);
-    list = next;
-  }
-}
-
-
-void luaK_patchtohere (FuncState *fs, int list) {
-  luaK_getlabel(fs);
-  luaK_concat(fs, &fs->jpc, list);
-}
-
-
-void luaK_concat (FuncState *fs, int *l1, int l2) {
-  if (l2 == NO_JUMP) return;
-  else if (*l1 == NO_JUMP)
-    *l1 = l2;
-  else {
-    int list = *l1;
-    int next;
-    while ((next = getjump(fs, list)) != NO_JUMP)  /* find last element */
-      list = next;
-    fixjump(fs, list, l2);
   }
 }
 
 
+/*
+** Emit instruction 'i', checking for array sizes and saving also its
+** line information. Return 'i' position.
+*/
 static int luaK_code (FuncState *fs, Instruction i) {
   Proto *f = fs->f;
   dischargejpc(fs);  /* 'pc' will change */
@@ -241,6 +305,10 @@ static int luaK_code (FuncState *fs, Instruction i) {
 }
 
 
+/*
+** Format and emit an 'iABC' instruction. (Assertions check consistency
+** of parameters versus opcode.)
+*/
 int luaK_codeABC (FuncState *fs, OpCode o, int a, int b, int c) {
   lua_assert(getOpMode(o) == iABC);
   lua_assert(getBMode(o) != OpArgN || b == 0);
@@ -250,6 +318,9 @@ int luaK_codeABC (FuncState *fs, OpCode o, int a, int b, int c) {
 }
 
 
+/*
+** Format and emit an 'iABx' instruction.
+*/
 int luaK_codeABx (FuncState *fs, OpCode o, int a, unsigned int bc) {
   lua_assert(getOpMode(o) == iABx || getOpMode(o) == iAsBx);
   lua_assert(getCMode(o) == OpArgN);
@@ -258,12 +329,20 @@ int luaK_codeABx (FuncState *fs, OpCode o, int a, unsigned int bc) {
 }
 
 
+/*
+** Emit an "extra argument" instruction (format 'iAx')
+*/
 static int codeextraarg (FuncState *fs, int a) {
   lua_assert(a <= MAXARG_Ax);
   return luaK_code(fs, CREATE_Ax(OP_EXTRAARG, a));
 }
 
 
+/*
+** Emit a "load constant" instruction, using either 'OP_LOADK'
+** (if constant index 'k' fits in 18 bits) or an 'OP_LOADKX'
+** instruction with "extra argument".
+*/
 int luaK_codek (FuncState *fs, int reg, int k) {
   if (k <= MAXARG_Bx)
     return luaK_codeABx(fs, OP_LOADK, reg, k);
@@ -275,6 +354,10 @@ int luaK_codek (FuncState *fs, int reg, int k) {
 }
 
 
+/*
+** Check register-stack level, keeping track of its maximum size
+** in field 'maxstacksize'
+*/
 void luaK_checkstack (FuncState *fs, int n) {
   int newstack = fs->freereg + n;
   if (newstack > fs->f->maxstacksize) {
@@ -286,12 +369,20 @@ void luaK_checkstack (FuncState *fs, int n) {
 }
 
 
+/*
+** Reserve 'n' registers in register stack
+*/
 void luaK_reserveregs (FuncState *fs, int n) {
   luaK_checkstack(fs, n);
   fs->freereg += n;
 }
 
 
+/*
+** Free register 'reg', if it is neither a constant index nor
+** a local variable.
+)
+*/
 static void freereg (FuncState *fs, int reg) {
   if (!ISK(reg) && reg >= fs->nactvar) {
     fs->freereg--;
@@ -300,6 +391,9 @@ static void freereg (FuncState *fs, int reg) {
 }
 
 
+/*
+** Free register used by expression 'e' (if any)
+*/
 static void freeexp (FuncState *fs, expdesc *e) {
   if (e->k == VNONRELOC)
     freereg(fs, e->u.info);
@@ -307,8 +401,29 @@ static void freeexp (FuncState *fs, expdesc *e) {
 
 
 /*
+** Free registers used by expressions 'e1' and 'e2' (if any) in proper
+** order.
+*/
+static void freeexps (FuncState *fs, expdesc *e1, expdesc *e2) {
+  int r1 = (e1->k == VNONRELOC) ? e1->u.info : -1;
+  int r2 = (e2->k == VNONRELOC) ? e2->u.info : -1;
+  if (r1 > r2) {
+    freereg(fs, r1);
+    freereg(fs, r2);
+  }
+  else {
+    freereg(fs, r2);
+    freereg(fs, r1);
+  }
+}
+
+
+/*
+** Add constant 'v' to prototype's list of constants (field 'k').
 ** Use scanner's table to cache position of constants in constant list
-** and try to reuse constants
+** and try to reuse constants. Because some values should not be used
+** as keys (nil cannot be a key, integer keys can collapse with float
+** keys), the caller must provide a useful 'key' for indexing the cache.
 */
 static int addk (FuncState *fs, TValue *key, TValue *v) {
   lua_State *L = fs->ls->L;
@@ -337,17 +452,21 @@ static int addk (FuncState *fs, TValue *key, TValue *v) {
 }
 
 
+/*
+** Add a string to list of constants and return its index.
+*/
 int luaK_stringK (FuncState *fs, TString *s) {
   TValue o;
   setsvalue(fs->ls->L, &o, s);
-  return addk(fs, &o, &o);
+  return addk(fs, &o, &o);  /* use string itself as key */
 }
 
 
 /*
-** Integers use userdata as keys to avoid collision with floats with same
-** value; conversion to 'void*' used only for hashing, no "precision"
-** problems
+** Add an integer to list of constants and return its index.
+** Integers use userdata as keys to avoid collision with floats with
+** same value; conversion to 'void*' is used only for hashing, so there
+** are no "precision" problems.
 */
 int luaK_intK (FuncState *fs, lua_Integer n) {
   TValue k, o;
@@ -356,21 +475,29 @@ int luaK_intK (FuncState *fs, lua_Integer n) {
   return addk(fs, &k, &o);
 }
 
-
+/*
+** Add a float to list of constants and return its index.
+*/
 static int luaK_numberK (FuncState *fs, lua_Number r) {
   TValue o;
   setfltvalue(&o, r);
-  return addk(fs, &o, &o);
+  return addk(fs, &o, &o);  /* use number itself as key */
 }
 
 
+/*
+** Add a boolean to list of constants and return its index.
+*/
 static int boolK (FuncState *fs, int b) {
   TValue o;
   setbvalue(&o, b);
-  return addk(fs, &o, &o);
+  return addk(fs, &o, &o);  /* use boolean itself as key */
 }
 
 
+/*
+** Add nil to list of constants and return its index.
+*/
 static int nilK (FuncState *fs) {
   TValue k, v;
   setnilvalue(&v);
@@ -380,54 +507,79 @@ static int nilK (FuncState *fs) {
 }
 
 
+/*
+** Fix an expression to return the number of results 'nresults'.
+** Either 'e' is a multi-ret expression (function call or vararg)
+** or 'nresults' is LUA_MULTRET (as any expression can satisfy that).
+*/
 void luaK_setreturns (FuncState *fs, expdesc *e, int nresults) {
   if (e->k == VCALL) {  /* expression is an open function call? */
-    SETARG_C(getcode(fs, e), nresults+1);
+    SETARG_C(getinstruction(fs, e), nresults + 1);
   }
   else if (e->k == VVARARG) {
-    SETARG_B(getcode(fs, e), nresults+1);
-    SETARG_A(getcode(fs, e), fs->freereg);
+    Instruction *pc = &getinstruction(fs, e);
+    SETARG_B(*pc, nresults + 1);
+    SETARG_A(*pc, fs->freereg);
     luaK_reserveregs(fs, 1);
   }
+  else lua_assert(nresults == LUA_MULTRET);
 }
 
 
+/*
+** Fix an expression to return one result.
+** If expression is not a multi-ret expression (function call or
+** vararg), it already returns one result, so nothing needs to be done.
+** Function calls become VNONRELOC expressions (as its result comes
+** fixed in the base register of the call), while vararg expressions
+** become VRELOCABLE (as OP_VARARG puts its results where it wants).
+** (Calls are created returning one result, so that does not need
+** to be fixed.)
+*/
 void luaK_setoneret (FuncState *fs, expdesc *e) {
   if (e->k == VCALL) {  /* expression is an open function call? */
-    e->k = VNONRELOC;
-    e->u.info = GETARG_A(getcode(fs, e));
+    /* already returns 1 value */
+    lua_assert(GETARG_C(getinstruction(fs, e)) == 2);
+    e->k = VNONRELOC;  /* result has fixed position */
+    e->u.info = GETARG_A(getinstruction(fs, e));
   }
   else if (e->k == VVARARG) {
-    SETARG_B(getcode(fs, e), 2);
+    SETARG_B(getinstruction(fs, e), 2);
     e->k = VRELOCABLE;  /* can relocate its simple result */
   }
 }
 
 
+/*
+** Ensure that expression 'e' is not a variable.
+*/
 void luaK_dischargevars (FuncState *fs, expdesc *e) {
   switch (e->k) {
-    case VLOCAL: {
-      e->k = VNONRELOC;
+    case VLOCAL: {  /* already in a register */
+      e->k = VNONRELOC;  /* becomes a non-relocatable value */
       break;
     }
-    case VUPVAL: {
+    case VUPVAL: {  /* move value to some (pending) register */
       e->u.info = luaK_codeABC(fs, OP_GETUPVAL, 0, e->u.info, 0);
       e->k = VRELOCABLE;
       break;
     }
     case VINDEXED: {
-      OpCode op = OP_GETTABUP;  /* assume 't' is in an upvalue */
+      OpCode op;
       freereg(fs, e->u.ind.idx);
-      if (e->u.ind.vt == VLOCAL) {  /* 't' is in a register? */
+      if (e->u.ind.vt == VLOCAL) {  /* is 't' in a register? */
         freereg(fs, e->u.ind.t);
         op = OP_GETTABLE;
       }
+      else {
+        lua_assert(e->u.ind.vt == VUPVAL);
+        op = OP_GETTABUP;  /* 't' is in an upvalue */
+      }
       e->u.info = luaK_codeABC(fs, op, 0, e->u.ind.t, e->u.ind.idx);
       e->k = VRELOCABLE;
       break;
     }
-    case VVARARG:
-    case VCALL: {
+    case VVARARG: case VCALL: {
       luaK_setoneret(fs, e);
       break;
     }
@@ -436,12 +588,10 @@ void luaK_dischargevars (FuncState *fs, expdesc *e) {
 }
 
 
-static int code_label (FuncState *fs, int A, int b, int jump) {
-  luaK_getlabel(fs);  /* those instructions may be jump targets */
-  return luaK_codeABC(fs, OP_LOADBOOL, A, b, jump);
-}
-
-
+/*
+** Ensures expression value is in register 'reg' (and therefore
+** 'e' will become a non-relocatable expression).
+*/
 static void discharge2reg (FuncState *fs, expdesc *e, int reg) {
   luaK_dischargevars(fs, e);
   switch (e->k) {
@@ -466,8 +616,8 @@ static void discharge2reg (FuncState *fs, expdesc *e, int reg) {
       break;
     }
     case VRELOCABLE: {
-      Instruction *pc = &getcode(fs, e);
-      SETARG_A(*pc, reg);
+      Instruction *pc = &getinstruction(fs, e);
+      SETARG_A(*pc, reg);  /* instruction will put result in 'reg' */
       break;
     }
     case VNONRELOC: {
@@ -476,7 +626,7 @@ static void discharge2reg (FuncState *fs, expdesc *e, int reg) {
       break;
     }
     default: {
-      lua_assert(e->k == VVOID || e->k == VJMP);
+      lua_assert(e->k == VJMP);
       return;  /* nothing to do... */
     }
   }
@@ -485,17 +635,46 @@ static void discharge2reg (FuncState *fs, expdesc *e, int reg) {
 }
 
 
+/*
+** Ensures expression value is in any register.
+*/
 static void discharge2anyreg (FuncState *fs, expdesc *e) {
-  if (e->k != VNONRELOC) {
-    luaK_reserveregs(fs, 1);
-    discharge2reg(fs, e, fs->freereg-1);
+  if (e->k != VNONRELOC) {  /* no fixed register yet? */
+    luaK_reserveregs(fs, 1);  /* get a register */
+    discharge2reg(fs, e, fs->freereg-1);  /* put value there */
   }
 }
 
 
+static int code_loadbool (FuncState *fs, int A, int b, int jump) {
+  luaK_getlabel(fs);  /* those instructions may be jump targets */
+  return luaK_codeABC(fs, OP_LOADBOOL, A, b, jump);
+}
+
+
+/*
+** check whether list has any jump that do not produce a value
+** or produce an inverted value
+*/
+static int need_value (FuncState *fs, int list) {
+  for (; list != NO_JUMP; list = getjump(fs, list)) {
+    Instruction i = *getjumpcontrol(fs, list);
+    if (GET_OPCODE(i) != OP_TESTSET) return 1;
+  }
+  return 0;  /* not found */
+}
+
+
+/*
+** Ensures final expression result (including results from its jump
+** lists) is in register 'reg'.
+** If expression has jumps, need to patch these jumps either to
+** its final position or to "load" instructions (for those tests
+** that do not produce values).
+*/
 static void exp2reg (FuncState *fs, expdesc *e, int reg) {
   discharge2reg(fs, e, reg);
-  if (e->k == VJMP)
+  if (e->k == VJMP)  /* expression itself is a test? */
     luaK_concat(fs, &e->t, e->u.info);  /* put this jump in 't' list */
   if (hasjumps(e)) {
     int final;  /* position after whole expression */
@@ -503,8 +682,8 @@ static void exp2reg (FuncState *fs, expdesc *e, int reg) {
     int p_t = NO_JUMP;  /* position of an eventual LOAD true */
     if (need_value(fs, e->t) || need_value(fs, e->f)) {
       int fj = (e->k == VJMP) ? NO_JUMP : luaK_jump(fs);
-      p_f = code_label(fs, reg, 0, 1);
-      p_t = code_label(fs, reg, 1, 0);
+      p_f = code_loadbool(fs, reg, 0, 1);
+      p_t = code_loadbool(fs, reg, 1, 0);
       luaK_patchtohere(fs, fj);
     }
     final = luaK_getlabel(fs);
@@ -517,6 +696,10 @@ static void exp2reg (FuncState *fs, expdesc *e, int reg) {
 }
 
 
+/*
+** Ensures final expression result (including results from its jump
+** lists) is in next available register.
+*/
 void luaK_exp2nextreg (FuncState *fs, expdesc *e) {
   luaK_dischargevars(fs, e);
   freeexp(fs, e);
@@ -525,26 +708,39 @@ void luaK_exp2nextreg (FuncState *fs, expdesc *e) {
 }
 
 
+/*
+** Ensures final expression result (including results from its jump
+** lists) is in some (any) register and return that register.
+*/
 int luaK_exp2anyreg (FuncState *fs, expdesc *e) {
   luaK_dischargevars(fs, e);
-  if (e->k == VNONRELOC) {
-    if (!hasjumps(e)) return e->u.info;  /* exp is already in a register */
+  if (e->k == VNONRELOC) {  /* expression already has a register? */
+    if (!hasjumps(e))  /* no jumps? */
+      return e->u.info;  /* result is already in a register */
     if (e->u.info >= fs->nactvar) {  /* reg. is not a local? */
-      exp2reg(fs, e, e->u.info);  /* put value on it */
+      exp2reg(fs, e, e->u.info);  /* put final result in it */
       return e->u.info;
     }
   }
-  luaK_exp2nextreg(fs, e);  /* default */
+  luaK_exp2nextreg(fs, e);  /* otherwise, use next available register */
   return e->u.info;
 }
 
 
+/*
+** Ensures final expression result is either in a register or in an
+** upvalue.
+*/
 void luaK_exp2anyregup (FuncState *fs, expdesc *e) {
   if (e->k != VUPVAL || hasjumps(e))
     luaK_exp2anyreg(fs, e);
 }
 
 
+/*
+** Ensures final expression result is either in a register or it is
+** a constant.
+*/
 void luaK_exp2val (FuncState *fs, expdesc *e) {
   if (hasjumps(e))
     luaK_exp2anyreg(fs, e);
@@ -553,35 +749,26 @@ void luaK_exp2val (FuncState *fs, expdesc *e) {
 }
 
 
+/*
+** Ensures final expression result is in a valid R/K index
+** (that is, it is either in a register or in 'k' with an index
+** in the range of R/K indices).
+** Returns R/K index.
+*/  
 int luaK_exp2RK (FuncState *fs, expdesc *e) {
   luaK_exp2val(fs, e);
-  switch (e->k) {
-    case VTRUE:
-    case VFALSE:
-    case VNIL: {
-      if (fs->nk <= MAXINDEXRK) {  /* constant fits in RK operand? */
-        e->u.info = (e->k == VNIL) ? nilK(fs) : boolK(fs, (e->k == VTRUE));
-        e->k = VK;
-        return RKASK(e->u.info);
-      }
-      else break;
-    }
-    case VKINT: {
-      e->u.info = luaK_intK(fs, e->u.ival);
-      e->k = VK;
-      goto vk;
-    }
-    case VKFLT: {
-      e->u.info = luaK_numberK(fs, e->u.nval);
-      e->k = VK;
-    }
-    /* FALLTHROUGH */
-    case VK: {
+  switch (e->k) {  /* move constants to 'k' */
+    case VTRUE: e->u.info = boolK(fs, 1); goto vk;
+    case VFALSE: e->u.info = boolK(fs, 0); goto vk;
+    case VNIL: e->u.info = nilK(fs); goto vk;
+    case VKINT: e->u.info = luaK_intK(fs, e->u.ival); goto vk;
+    case VKFLT: e->u.info = luaK_numberK(fs, e->u.nval); goto vk;
+    case VK:
      vk:
+      e->k = VK;
       if (e->u.info <= MAXINDEXRK)  /* constant fits in 'argC'? */
         return RKASK(e->u.info);
       else break;
-    }
     default: break;
   }
   /* not a constant in the right range: put it in a register */
@@ -589,11 +776,14 @@ int luaK_exp2RK (FuncState *fs, expdesc *e) {
 }
 
 
+/*
+** Generate code to store result of expression 'ex' into variable 'var'.
+*/
 void luaK_storevar (FuncState *fs, expdesc *var, expdesc *ex) {
   switch (var->k) {
     case VLOCAL: {
       freeexp(fs, ex);
-      exp2reg(fs, ex, var->u.info);
+      exp2reg(fs, ex, var->u.info);  /* compute 'ex' into proper place */
       return;
     }
     case VUPVAL: {
@@ -607,29 +797,32 @@ void luaK_storevar (FuncState *fs, expdesc *var, expdesc *ex) {
       luaK_codeABC(fs, op, var->u.ind.t, var->u.ind.idx, e);
       break;
     }
-    default: {
-      lua_assert(0);  /* invalid var kind to store */
-      break;
-    }
+    default: lua_assert(0);  /* invalid var kind to store */
   }
   freeexp(fs, ex);
 }
 
 
+/*
+** Emit SELF instruction (convert expression 'e' into 'e:key(e,').
+*/
 void luaK_self (FuncState *fs, expdesc *e, expdesc *key) {
   int ereg;
   luaK_exp2anyreg(fs, e);
   ereg = e->u.info;  /* register where 'e' was placed */
   freeexp(fs, e);
   e->u.info = fs->freereg;  /* base register for op_self */
-  e->k = VNONRELOC;
+  e->k = VNONRELOC;  /* self expression has a fixed register */
   luaK_reserveregs(fs, 2);  /* function and 'self' produced by op_self */
   luaK_codeABC(fs, OP_SELF, e->u.info, ereg, luaK_exp2RK(fs, key));
   freeexp(fs, key);
 }
 
 
-static void invertjump (FuncState *fs, expdesc *e) {
+/*
+** Negate condition 'e' (where 'e' is a comparison).
+*/
+static void negatecondition (FuncState *fs, expdesc *e) {
   Instruction *pc = getjumpcontrol(fs, e->u.info);
   lua_assert(testTMode(GET_OPCODE(*pc)) && GET_OPCODE(*pc) != OP_TESTSET &&
                                            GET_OPCODE(*pc) != OP_TEST);
@@ -637,9 +830,15 @@ static void invertjump (FuncState *fs, expdesc *e) {
 }
 
 
+/*
+** Emit instruction to jump if 'e' is 'cond' (that is, if 'cond'
+** is true, code will jump if 'e' is true.) Return jump position.
+** Optimize when 'e' is 'not' something, inverting the condition
+** and removing the 'not'.
+*/
 static int jumponcond (FuncState *fs, expdesc *e, int cond) {
   if (e->k == VRELOCABLE) {
-    Instruction ie = getcode(fs, e);
+    Instruction ie = getinstruction(fs, e);
     if (GET_OPCODE(ie) == OP_NOT) {
       fs->pc--;  /* remove previous OP_NOT */
       return condjump(fs, OP_TEST, GETARG_B(ie), 0, !cond);
@@ -652,13 +851,16 @@ static int jumponcond (FuncState *fs, expdesc *e, int cond) {
 }
 
 
+/*
+** Emit code to go through if 'e' is true, jump otherwise.
+*/
 void luaK_goiftrue (FuncState *fs, expdesc *e) {
-  int pc;  /* pc of last jump */
+  int pc;  /* pc of new jump */
   luaK_dischargevars(fs, e);
   switch (e->k) {
-    case VJMP: {
-      invertjump(fs, e);
-      pc = e->u.info;
+    case VJMP: {  /* condition? */
+      negatecondition(fs, e);  /* jump when it is false */
+      pc = e->u.info;  /* save jump position */
       break;
     }
     case VK: case VKFLT: case VKINT: case VTRUE: {
@@ -666,22 +868,25 @@ void luaK_goiftrue (FuncState *fs, expdesc *e) {
       break;
     }
     default: {
-      pc = jumponcond(fs, e, 0);
+      pc = jumponcond(fs, e, 0);  /* jump when false */
       break;
     }
   }
-  luaK_concat(fs, &e->f, pc);  /* insert last jump in 'f' list */
-  luaK_patchtohere(fs, e->t);
+  luaK_concat(fs, &e->f, pc);  /* insert new jump in false list */
+  luaK_patchtohere(fs, e->t);  /* true list jumps to here (to go through) */
   e->t = NO_JUMP;
 }
 
 
+/*
+** Emit code to go through if 'e' is false, jump otherwise.
+*/
 void luaK_goiffalse (FuncState *fs, expdesc *e) {
-  int pc;  /* pc of last jump */
+  int pc;  /* pc of new jump */
   luaK_dischargevars(fs, e);
   switch (e->k) {
     case VJMP: {
-      pc = e->u.info;
+      pc = e->u.info;  /* already jump if true */
       break;
     }
     case VNIL: case VFALSE: {
@@ -689,29 +894,32 @@ void luaK_goiffalse (FuncState *fs, expdesc *e) {
       break;
     }
     default: {
-      pc = jumponcond(fs, e, 1);
+      pc = jumponcond(fs, e, 1);  /* jump if true */
       break;
     }
   }
-  luaK_concat(fs, &e->t, pc);  /* insert last jump in 't' list */
-  luaK_patchtohere(fs, e->f);
+  luaK_concat(fs, &e->t, pc);  /* insert new jump in 't' list */
+  luaK_patchtohere(fs, e->f);  /* false list jumps to here (to go through) */
   e->f = NO_JUMP;
 }
 
 
+/*
+** Code 'not e', doing constant folding.
+*/
 static void codenot (FuncState *fs, expdesc *e) {
   luaK_dischargevars(fs, e);
   switch (e->k) {
     case VNIL: case VFALSE: {
-      e->k = VTRUE;
+      e->k = VTRUE;  /* true == not nil == not false */
       break;
     }
     case VK: case VKFLT: case VKINT: case VTRUE: {
-      e->k = VFALSE;
+      e->k = VFALSE;  /* false == not "x" == not 0.5 == not 1 == not true */
       break;
     }
     case VJMP: {
-      invertjump(fs, e);
+      negatecondition(fs, e);
       break;
     }
     case VRELOCABLE:
@@ -722,30 +930,32 @@ static void codenot (FuncState *fs, expdesc *e) {
       e->k = VRELOCABLE;
       break;
     }
-    default: {
-      lua_assert(0);  /* cannot happen */
-      break;
-    }
+    default: lua_assert(0);  /* cannot happen */
   }
   /* interchange true and false lists */
   { int temp = e->f; e->f = e->t; e->t = temp; }
-  removevalues(fs, e->f);
+  removevalues(fs, e->f);  /* values are useless when negated */
   removevalues(fs, e->t);
 }
 
 
+/*
+** Create expression 't[k]'. 't' must have its final result already in a
+** register or upvalue.
+*/
 void luaK_indexed (FuncState *fs, expdesc *t, expdesc *k) {
-  lua_assert(!hasjumps(t));
-  t->u.ind.t = t->u.info;
-  t->u.ind.idx = luaK_exp2RK(fs, k);
-  t->u.ind.vt = (t->k == VUPVAL) ? VUPVAL
-                                 : check_exp(vkisinreg(t->k), VLOCAL);
+  lua_assert(!hasjumps(t) && (vkisinreg(t->k) || t->k == VUPVAL));
+  t->u.ind.t = t->u.info;  /* register or upvalue index */
+  t->u.ind.idx = luaK_exp2RK(fs, k);  /* R/K index for key */
+  t->u.ind.vt = (t->k == VUPVAL) ? VUPVAL : VLOCAL;
   t->k = VINDEXED;
 }
 
 
 /*
-** return false if folding can raise an error
+** Return false if folding can raise an error.
+** Bitwise operations need operands convertible to integers; division
+** operations cannot have 0 as divisor.
 */
 static int validop (int op, TValue *v1, TValue *v2) {
   switch (op) {
@@ -762,7 +972,8 @@ static int validop (int op, TValue *v1, TValue *v2) {
 
 
 /*
-** Try to "constant-fold" an operation; return 1 iff successful
+** Try to "constant-fold" an operation; return 1 iff successful.
+** (In this case, 'e1' has the final result.)
 */
 static int constfolding (FuncState *fs, int op, expdesc *e1, expdesc *e2) {
   TValue v1, v2, res;
@@ -773,7 +984,7 @@ static int constfolding (FuncState *fs, int op, expdesc *e1, expdesc *e2) {
     e1->k = VKINT;
     e1->u.ival = ivalue(&res);
   }
-  else {  /* folds neither NaN nor 0.0 (to avoid collapsing with -0.0) */
+  else {  /* folds neither NaN nor 0.0 (to avoid problems with -0.0) */
     lua_Number n = fltvalue(&res);
     if (luai_numisnan(n) || n == 0)
       return 0;
@@ -785,81 +996,97 @@ static int constfolding (FuncState *fs, int op, expdesc *e1, expdesc *e2) {
 
 
 /*
-** Code for binary and unary expressions that "produce values"
-** (arithmetic operations, bitwise operations, concat, length). First
-** try to do constant folding (only for numeric [arithmetic and
-** bitwise] operations, which is what 'lua_arith' accepts).
-** Expression to produce final result will be encoded in 'e1'.
+** Emit code for unary expressions that "produce values"
+** (everything but 'not').
+** Expression to produce final result will be encoded in 'e'.
 */
-static void codeexpval (FuncState *fs, OpCode op,
-                        expdesc *e1, expdesc *e2, int line) {
-  lua_assert(op >= OP_ADD);
-  if (op <= OP_BNOT && constfolding(fs, (op - OP_ADD) + LUA_OPADD, e1, e2))
-    return;  /* result has been folded */
-  else {
-    int o1, o2;
-    /* move operands to registers (if needed) */
-    if (op == OP_UNM || op == OP_BNOT || op == OP_LEN) {  /* unary op? */
-      o2 = 0;  /* no second expression */
-      o1 = luaK_exp2anyreg(fs, e1);  /* cannot operate on constants */
-    }
-    else {  /* regular case (binary operators) */
-      o2 = luaK_exp2RK(fs, e2);  /* both operands are "RK" */
-      o1 = luaK_exp2RK(fs, e1);
-    }
-    if (o1 > o2) {  /* free registers in proper order */
-      freeexp(fs, e1);
-      freeexp(fs, e2);
-    }
-    else {
-      freeexp(fs, e2);
-      freeexp(fs, e1);
-    }
-    e1->u.info = luaK_codeABC(fs, op, 0, o1, o2);  /* generate opcode */
-    e1->k = VRELOCABLE;  /* all those operations are relocatable */
-    luaK_fixline(fs, line);
-  }
+static void codeunexpval (FuncState *fs, OpCode op, expdesc *e, int line) {
+  int r = luaK_exp2anyreg(fs, e);  /* opcodes operate only on registers */
+  freeexp(fs, e);
+  e->u.info = luaK_codeABC(fs, op, 0, r, 0);  /* generate opcode */
+  e->k = VRELOCABLE;  /* all those operations are relocatable */
+  luaK_fixline(fs, line);
 }
 
 
-static void codecomp (FuncState *fs, OpCode op, int cond, expdesc *e1,
-                                                          expdesc *e2) {
-  int o1 = luaK_exp2RK(fs, e1);
-  int o2 = luaK_exp2RK(fs, e2);
-  freeexp(fs, e2);
-  freeexp(fs, e1);
-  if (cond == 0 && op != OP_EQ) {
-    int temp;  /* exchange args to replace by '<' or '<=' */
-    temp = o1; o1 = o2; o2 = temp;  /* o1 <==> o2 */
-    cond = 1;
+/*
+** Emit code for binary expressions that "produce values"
+** (everything but logical operators 'and'/'or' and comparison
+** operators).
+** Expression to produce final result will be encoded in 'e1'.
+*/
+static void codebinexpval (FuncState *fs, OpCode op,
+                           expdesc *e1, expdesc *e2, int line) {
+  int rk1 = luaK_exp2RK(fs, e1);  /* both operands are "RK" */
+  int rk2 = luaK_exp2RK(fs, e2);
+  freeexps(fs, e1, e2);
+  e1->u.info = luaK_codeABC(fs, op, 0, rk1, rk2);  /* generate opcode */
+  e1->k = VRELOCABLE;  /* all those operations are relocatable */
+  luaK_fixline(fs, line);
+}
+
+
+/*
+** Emit code for comparisons.
+** 'e1' was already put in R/K form by 'luaK_infix'.
+*/
+static void codecomp (FuncState *fs, BinOpr opr, expdesc *e1, expdesc *e2) {
+  int rk1 = (e1->k == VK) ? RKASK(e1->u.info)
+                          : check_exp(e1->k == VNONRELOC, e1->u.info);
+  int rk2 = luaK_exp2RK(fs, e2);
+  freeexps(fs, e1, e2);
+  switch (opr) {
+    case OPR_NE: {  /* '(a ~= b)' ==> 'not (a == b)' */
+      e1->u.info = condjump(fs, OP_EQ, 0, rk1, rk2);
+      break;
+    }
+    case OPR_GT: case OPR_GE: {
+      /* '(a > b)' ==> '(b < a)';  '(a >= b)' ==> '(b <= a)' */
+      OpCode op = cast(OpCode, (opr - OPR_NE) + OP_EQ);
+      e1->u.info = condjump(fs, op, 1, rk2, rk1);  /* invert operands */
+      break;
+    }
+    default: {  /* '==', '<', '<=' use their own opcodes */
+      OpCode op = cast(OpCode, (opr - OPR_EQ) + OP_EQ);
+      e1->u.info = condjump(fs, op, 1, rk1, rk2);
+      break;
+    }
   }
-  e1->u.info = condjump(fs, op, cond, o1, o2);
   e1->k = VJMP;
 }
 
 
+/*
+** Aplly prefix operation 'op' to expression 'e'.
+*/
 void luaK_prefix (FuncState *fs, UnOpr op, expdesc *e, int line) {
-  expdesc e2;
-  e2.t = e2.f = NO_JUMP; e2.k = VKINT; e2.u.ival = 0;
+  static expdesc ef = {VKINT, {0}, NO_JUMP, NO_JUMP};  /* fake 2nd operand */
   switch (op) {
-    case OPR_MINUS: case OPR_BNOT: case OPR_LEN: {
-      codeexpval(fs, cast(OpCode, (op - OPR_MINUS) + OP_UNM), e, &e2, line);
+    case OPR_MINUS: case OPR_BNOT:
+      if (constfolding(fs, op + LUA_OPUNM, e, &ef))
+        break;
+      /* FALLTHROUGH */
+    case OPR_LEN:
+      codeunexpval(fs, cast(OpCode, op + OP_UNM), e, line);
       break;
-    }
     case OPR_NOT: codenot(fs, e); break;
     default: lua_assert(0);
   }
 }
 
 
+/*
+** Process 1st operand 'v' of binary operation 'op' before reading
+** 2nd operand.
+*/
 void luaK_infix (FuncState *fs, BinOpr op, expdesc *v) {
   switch (op) {
     case OPR_AND: {
-      luaK_goiftrue(fs, v);
+      luaK_goiftrue(fs, v);  /* go ahead only if 'v' is true */
       break;
     }
     case OPR_OR: {
-      luaK_goiffalse(fs, v);
+      luaK_goiffalse(fs, v);  /* go ahead only if 'v' is false */
       break;
     }
     case OPR_CONCAT: {
@@ -871,7 +1098,9 @@ void luaK_infix (FuncState *fs, BinOpr op, expdesc *v) {
     case OPR_MOD: case OPR_POW:
     case OPR_BAND: case OPR_BOR: case OPR_BXOR:
     case OPR_SHL: case OPR_SHR: {
-      if (!tonumeral(v, NULL)) luaK_exp2RK(fs, v);
+      if (!tonumeral(v, NULL))
+        luaK_exp2RK(fs, v);
+      /* else keep numeral, which may be folded with 2nd operand */
       break;
     }
     default: {
@@ -882,18 +1111,24 @@ void luaK_infix (FuncState *fs, BinOpr op, expdesc *v) {
 }
 
 
+/*
+** Finalize code for binary operation, after reading 2nd operand.
+** For '(a .. b .. c)' (which is '(a .. (b .. c))', because
+** concatenation is right associative), merge second CONCAT into first
+** one.
+*/
 void luaK_posfix (FuncState *fs, BinOpr op,
                   expdesc *e1, expdesc *e2, int line) {
   switch (op) {
     case OPR_AND: {
-      lua_assert(e1->t == NO_JUMP);  /* list must be closed */
+      lua_assert(e1->t == NO_JUMP);  /* list closed by 'luK_infix' */
       luaK_dischargevars(fs, e2);
       luaK_concat(fs, &e2->f, e1->f);
       *e1 = *e2;
       break;
     }
     case OPR_OR: {
-      lua_assert(e1->f == NO_JUMP);  /* list must be closed */
+      lua_assert(e1->f == NO_JUMP);  /* list closed by 'luK_infix' */
       luaK_dischargevars(fs, e2);
       luaK_concat(fs, &e2->t, e1->t);
       *e1 = *e2;
@@ -901,15 +1136,16 @@ void luaK_posfix (FuncState *fs, BinOpr op,
     }
     case OPR_CONCAT: {
       luaK_exp2val(fs, e2);
-      if (e2->k == VRELOCABLE && GET_OPCODE(getcode(fs, e2)) == OP_CONCAT) {
-        lua_assert(e1->u.info == GETARG_B(getcode(fs, e2))-1);
+      if (e2->k == VRELOCABLE &&
+          GET_OPCODE(getinstruction(fs, e2)) == OP_CONCAT) {
+        lua_assert(e1->u.info == GETARG_B(getinstruction(fs, e2))-1);
         freeexp(fs, e1);
-        SETARG_B(getcode(fs, e2), e1->u.info);
+        SETARG_B(getinstruction(fs, e2), e1->u.info);
         e1->k = VRELOCABLE; e1->u.info = e2->u.info;
       }
       else {
         luaK_exp2nextreg(fs, e2);  /* operand must be on the 'stack' */
-        codeexpval(fs, OP_CONCAT, e1, e2, line);
+        codebinexpval(fs, OP_CONCAT, e1, e2, line);
       }
       break;
     }
@@ -917,15 +1153,13 @@ void luaK_posfix (FuncState *fs, BinOpr op,
     case OPR_IDIV: case OPR_MOD: case OPR_POW:
     case OPR_BAND: case OPR_BOR: case OPR_BXOR:
     case OPR_SHL: case OPR_SHR: {
-      codeexpval(fs, cast(OpCode, (op - OPR_ADD) + OP_ADD), e1, e2, line);
-      break;
-    }
-    case OPR_EQ: case OPR_LT: case OPR_LE: {
-      codecomp(fs, cast(OpCode, (op - OPR_EQ) + OP_EQ), 1, e1, e2);
+      if (!constfolding(fs, op + LUA_OPADD, e1, e2))
+        codebinexpval(fs, cast(OpCode, op + OP_ADD), e1, e2, line);
       break;
     }
+    case OPR_EQ: case OPR_LT: case OPR_LE:
     case OPR_NE: case OPR_GT: case OPR_GE: {
-      codecomp(fs, cast(OpCode, (op - OPR_NE) + OP_EQ), 0, e1, e2);
+      codecomp(fs, op, e1, e2);
       break;
     }
     default: lua_assert(0);
@@ -933,15 +1167,25 @@ void luaK_posfix (FuncState *fs, BinOpr op,
 }
 
 
+/*
+** Change line information associated with current position.
+*/
 void luaK_fixline (FuncState *fs, int line) {
   fs->f->lineinfo[fs->pc - 1] = line;
 }
 
 
+/*
+** Emit a SETLIST instruction.
+** 'base' is register that keeps table;
+** 'nelems' is #table plus those to be stored now;
+** 'tostore' is number of values (in registers 'base + 1',...) to add to
+** table (or LUA_MULTRET to add up to stack top).
+*/
 void luaK_setlist (FuncState *fs, int base, int nelems, int tostore) {
   int c =  (nelems - 1)/LFIELDS_PER_FLUSH + 1;
   int b = (tostore == LUA_MULTRET) ? 0 : tostore;
-  lua_assert(tostore != 0);
+  lua_assert(tostore != 0 && tostore <= LFIELDS_PER_FLUSH);
   if (c <= MAXARG_C)
     luaK_codeABC(fs, OP_SETLIST, base, b, c);
   else if (c <= MAXARG_Ax) {
diff --git a/lua/lcode.h b/lua/lcode.h
index 43ab86d..cd306d5 100644
--- a/lua/lcode.h
+++ b/lua/lcode.h
@@ -1,5 +1,5 @@
 /*
-** $Id: lcode.h,v 1.63 2013/12/30 20:47:58 roberto Exp $
+** $Id: lcode.h,v 1.64 2016/01/05 16:22:37 roberto Exp $
 ** Code generator for Lua
 ** See Copyright Notice in lua.h
 */
@@ -40,7 +40,8 @@ typedef enum BinOpr {
 typedef enum UnOpr { OPR_MINUS, OPR_BNOT, OPR_NOT, OPR_LEN, OPR_NOUNOPR } UnOpr;
 
 
-#define getcode(fs,e)	((fs)->f->code[(e)->u.info])
+/* get (pointer to) instruction of given 'expdesc' */
+#define getinstruction(fs,e)	((fs)->f->code[(e)->u.info])
 
 #define luaK_codeAsBx(fs,o,A,sBx)	luaK_codeABx(fs,o,A,(sBx)+MAXARG_sBx)
 
diff --git a/lua/lcorolib.c b/lua/lcorolib.c
index 0c0b7fa..2303429 100644
--- a/lua/lcorolib.c
+++ b/lua/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/lua/ldebug.c b/lua/ldebug.c
index 9bd86d0..e499ee3 100644
--- a/lua/ldebug.c
+++ b/lua/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
 */
@@ -69,7 +69,13 @@ static void swapextra (lua_State *L) {
 
 
 /*
-** this function can be called asynchronous (e.g. during a signal)
+** This function can be called asynchronously (e.g. during a signal).
+** Fields 'oldpc', 'basehookcount', and 'hookcount' (set by
+** 'resethookcount') are for debug only, and it is no problem if they
+** get arbitrary values (causes at most one wrong hook call). 'hookmask'
+** is an atomic value. We assume that pointers are atomic too (e.g., gcc
+** ensures that for all platforms where it runs). Moreover, 'hook' is
+** always checked before being called (see 'luaD_hook').
 */
 LUA_API void lua_sethook (lua_State *L, lua_Hook func, int mask, int count) {
   if (func == NULL || mask == 0) {  /* turn off hooks? */
@@ -558,7 +564,7 @@ static const char *varinfo (lua_State *L, const TValue *o) {
 
 
 l_noret luaG_typeerror (lua_State *L, const TValue *o, const char *op) {
-  const char *t = objtypename(o);
+  const char *t = luaT_objtypename(L, o);
   luaG_runerror(L, "attempt to %s a %s value%s", op, t, varinfo(L, o));
 }
 
@@ -590,9 +596,9 @@ l_noret luaG_tointerror (lua_State *L, const TValue *p1, const TValue *p2) {
 
 
 l_noret luaG_ordererror (lua_State *L, const TValue *p1, const TValue *p2) {
-  const char *t1 = objtypename(p1);
-  const char *t2 = objtypename(p2);
-  if (t1 == t2)
+  const char *t1 = luaT_objtypename(L, p1);
+  const char *t2 = luaT_objtypename(L, p2);
+  if (strcmp(t1, t2) == 0)
     luaG_runerror(L, "attempt to compare two %s values", t1);
   else
     luaG_runerror(L, "attempt to compare %s with %s", t1, t2);
diff --git a/lua/ldo.c b/lua/ldo.c
index 95efd56..8804c99 100644
--- a/lua/ldo.c
+++ b/lua/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
 */
@@ -242,9 +242,14 @@ void luaD_inctop (lua_State *L) {
 /* }================================================================== */
 
 
+/*
+** Call a hook for the given event. Make sure there is a hook to be
+** called. (Both 'L->hook' and 'L->hookmask', which triggers this
+** function, can be changed asynchronously by signals.)
+*/
 void luaD_hook (lua_State *L, int event, int line) {
   lua_Hook hook = L->hook;
-  if (hook && L->allowhook) {
+  if (hook && L->allowhook) {  /* make sure there is a hook */
     CallInfo *ci = L->ci;
     ptrdiff_t top = savestack(L, L->top);
     ptrdiff_t ci_top = savestack(L, ci->top);
diff --git a/lua/ldo.h b/lua/ldo.h
index 80582dc..4f5d51c 100644
--- a/lua/ldo.h
+++ b/lua/ldo.h
@@ -1,5 +1,5 @@
 /*
-** $Id: ldo.h,v 2.28 2015/11/23 11:29:43 roberto Exp $
+** $Id: ldo.h,v 2.29 2015/12/21 13:02:14 roberto Exp $
 ** Stack and Call structure of Lua
 ** See Copyright Notice in lua.h
 */
@@ -25,7 +25,7 @@
 	  { pre; luaD_growstack(L, n); pos; } else { condmovestack(L,pre,pos); }
 
 /* In general, 'pre'/'pos' are empty (nothing to save) */
-#define luaD_checkstack(L,n)	luaD_checkstackaux(L,n,,)
+#define luaD_checkstack(L,n)	luaD_checkstackaux(L,n,(void)0,(void)0)
 
 
 
diff --git a/lua/lgc.c b/lua/lgc.c
index 49d8ecb..7c29fb0 100644
--- a/lua/lgc.c
+++ b/lua/lgc.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lgc.c,v 2.210 2015/11/03 18:10:44 roberto Exp $
+** $Id: lgc.c,v 2.212 2016/03/31 19:02:03 roberto Exp $
 ** Garbage Collector
 ** See Copyright Notice in lua.h
 */
@@ -754,14 +754,11 @@ static GCObject **sweeplist (lua_State *L, GCObject **p, lu_mem count) {
 /*
 ** sweep a list until a live object (or end of list)
 */
-static GCObject **sweeptolive (lua_State *L, GCObject **p, int *n) {
+static GCObject **sweeptolive (lua_State *L, GCObject **p) {
   GCObject **old = p;
-  int i = 0;
   do {
-    i++;
     p = sweeplist(L, p, 1);
   } while (p == old);
-  if (n) *n += i;
   return p;
 }
 
@@ -856,10 +853,10 @@ static int runafewfinalizers (lua_State *L) {
 /*
 ** call all pending finalizers
 */
-static void callallpendingfinalizers (lua_State *L, int propagateerrors) {
+static void callallpendingfinalizers (lua_State *L) {
   global_State *g = G(L);
   while (g->tobefnz)
-    GCTM(L, propagateerrors);
+    GCTM(L, 0);
 }
 
 
@@ -909,7 +906,7 @@ void luaC_checkfinalizer (lua_State *L, GCObject *o, Table *mt) {
     if (issweepphase(g)) {
       makewhite(g, o);  /* "sweep" object 'o' */
       if (g->sweepgc == &o->next)  /* should not remove 'sweepgc' object */
-        g->sweepgc = sweeptolive(L, g->sweepgc, NULL);  /* change 'sweepgc' */
+        g->sweepgc = sweeptolive(L, g->sweepgc);  /* change 'sweepgc' */
     }
     /* search for pointer pointing to 'o' */
     for (p = &g->allgc; *p != o; p = &(*p)->next) { /* empty */ }
@@ -951,19 +948,16 @@ static void setpause (global_State *g) {
 
 /*
 ** Enter first sweep phase.
-** The call to 'sweeptolive' makes pointer point to an object inside
-** the list (instead of to the header), so that the real sweep do not
-** need to skip objects created between "now" and the start of the real
-** sweep.
-** Returns how many objects it swept.
+** The call to 'sweeplist' tries to make pointer point to an object
+** inside the list (instead of to the header), so that the real sweep do
+** not need to skip objects created between "now" and the start of the
+** real sweep.
 */
-static int entersweep (lua_State *L) {
+static void entersweep (lua_State *L) {
   global_State *g = G(L);
-  int n = 0;
   g->gcstate = GCSswpallgc;
   lua_assert(g->sweepgc == NULL);
-  g->sweepgc = sweeptolive(L, &g->allgc, &n);
-  return n;
+  g->sweepgc = sweeplist(L, &g->allgc, 1);
 }
 
 
@@ -971,7 +965,7 @@ void luaC_freeallobjects (lua_State *L) {
   global_State *g = G(L);
   separatetobefnz(g, 1);  /* separate all objects with finalizers */
   lua_assert(g->finobj == NULL);
-  callallpendingfinalizers(L, 0);
+  callallpendingfinalizers(L);
   lua_assert(g->tobefnz == NULL);
   g->currentwhite = WHITEBITS; /* this "white" makes all objects look dead */
   g->gckind = KGC_NORMAL;
@@ -1064,12 +1058,11 @@ static lu_mem singlestep (lua_State *L) {
     }
     case GCSatomic: {
       lu_mem work;
-      int sw;
       propagateall(g);  /* make sure gray list is empty */
       work = atomic(L);  /* work is what was traversed by 'atomic' */
-      sw = entersweep(L);
+      entersweep(L);
       g->GCestimate = gettotalbytes(g);  /* first estimate */;
-      return work + sw * GCSWEEPCOST;
+      return work;
     }
     case GCSswpallgc: {  /* sweep "regular" objects */
       return sweepstep(L, g, GCSswpfinobj, &g->finobj);
diff --git a/lua/lgc.h b/lua/lgc.h
index 1775ca4..aed3e18 100644
--- a/lua/lgc.h
+++ b/lua/lgc.h
@@ -1,5 +1,5 @@
 /*
-** $Id: lgc.h,v 2.90 2015/10/21 18:15:15 roberto Exp $
+** $Id: lgc.h,v 2.91 2015/12/21 13:02:14 roberto Exp $
 ** Garbage Collector
 ** See Copyright Notice in lua.h
 */
@@ -112,7 +112,7 @@
 	  condchangemem(L,pre,pos); }
 
 /* more often than not, 'pre'/'pos' are empty */
-#define luaC_checkGC(L)		luaC_condGC(L,,)
+#define luaC_checkGC(L)		luaC_condGC(L,(void)0,(void)0)
 
 
 #define luaC_barrier(L,p,v) (  \
diff --git a/lua/liolib.c b/lua/liolib.c
index a91ba39..aa78e59 100644
--- a/lua/liolib.c
+++ b/lua/liolib.c
@@ -1,5 +1,5 @@
 /*
-** $Id: liolib.c,v 2.148 2015/11/23 11:36:11 roberto Exp $
+** $Id: liolib.c,v 2.149 2016/05/02 14:03:19 roberto Exp $
 ** Standard I/O (and system) library
 ** See Copyright Notice in lua.h
 */
@@ -375,14 +375,17 @@ static int io_lines (lua_State *L) {
 
 
 /* maximum length of a numeral */
-#define MAXRN		200
+#if !defined (L_MAXLENNUM)
+#define L_MAXLENNUM     200
+#endif
+
 
 /* auxiliary structure used by 'read_number' */
 typedef struct {
   FILE *f;  /* file being read */
   int c;  /* current character (look ahead) */
   int n;  /* number of elements in buffer 'buff' */
-  char buff[MAXRN + 1];  /* +1 for ending '\0' */
+  char buff[L_MAXLENNUM + 1];  /* +1 for ending '\0' */
 } RN;
 
 
@@ -390,7 +393,7 @@ typedef struct {
 ** Add current char to buffer (if not out of space) and read next one
 */
 static int nextc (RN *rn) {
-  if (rn->n >= MAXRN) {  /* buffer overflow? */
+  if (rn->n >= L_MAXLENNUM) {  /* buffer overflow? */
     rn->buff[0] = '\0';  /* invalidate result */
     return 0;  /* fail */
   }
@@ -403,10 +406,10 @@ static int nextc (RN *rn) {
 
 
 /*
-** Accept current char if it is in 'set' (of size 1 or 2)
+** Accept current char if it is in 'set' (of size 2)
 */
 static int test2 (RN *rn, const char *set) {
-  if (rn->c == set[0] || (rn->c == set[1] && rn->c != '\0'))
+  if (rn->c == set[0] || rn->c == set[1])
     return nextc(rn);
   else return 0;
 }
@@ -435,11 +438,11 @@ static int read_number (lua_State *L, FILE *f) {
   char decp[2];
   rn.f = f; rn.n = 0;
   decp[0] = lua_getlocaledecpoint();  /* get decimal point from locale */
-  decp[1] = '\0';
+  decp[1] = '.';  /* always accept a dot */
   l_lockfile(rn.f);
   do { rn.c = l_getc(rn.f); } while (isspace(rn.c));  /* skip spaces */
   test2(&rn, "-+");  /* optional signal */
-  if (test2(&rn, "0")) {
+  if (test2(&rn, "00")) {
     if (test2(&rn, "xX")) hex = 1;  /* numeral is hexadecimal */
     else count = 1;  /* count initial '0' as a valid digit */
   }
diff --git a/lua/llex.c b/lua/llex.c
index 16ea3eb..7032827 100644
--- a/lua/llex.c
+++ b/lua/llex.c
@@ -1,5 +1,5 @@
 /*
-** $Id: llex.c,v 2.95 2015/11/19 19:16:22 roberto Exp $
+** $Id: llex.c,v 2.96 2016/05/02 14:02:12 roberto Exp $
 ** Lexical Analyzer
 ** See Copyright Notice in lua.h
 */
@@ -162,7 +162,6 @@ static void inclinenumber (LexState *ls) {
 void luaX_setinput (lua_State *L, LexState *ls, ZIO *z, TString *source,
                     int firstchar) {
   ls->t.token = 0;
-  ls->decpoint = '.';
   ls->L = L;
   ls->current = firstchar;
   ls->lookahead.token = TK_EOS;  /* no look-ahead token */
@@ -207,35 +206,6 @@ static int check_next2 (LexState *ls, const char *set) {
 }
 
 
-/*
-** change all characters 'from' in buffer to 'to'
-*/
-static void buffreplace (LexState *ls, char from, char to) {
-  if (from != to) {
-    size_t n = luaZ_bufflen(ls->buff);
-    char *p = luaZ_buffer(ls->buff);
-    while (n--)
-      if (p[n] == from) p[n] = to;
-  }
-}
-
-
-/*
-** in case of format error, try to change decimal point separator to
-** the one defined in the current locale and check again
-*/
-static void trydecpoint (LexState *ls, TValue *o) {
-  char old = ls->decpoint;
-  ls->decpoint = lua_getlocaledecpoint();
-  buffreplace(ls, old, ls->decpoint);  /* try new decimal separator */
-  if (luaO_str2num(luaZ_buffer(ls->buff), o) == 0) {
-    /* format error with correct decimal point: no more options */
-    buffreplace(ls, ls->decpoint, '.');  /* undo change (for error message) */
-    lexerror(ls, "malformed number", TK_FLT);
-  }
-}
-
-
 /* LUA_NUMBER */
 /*
 ** this function is quite liberal in what it accepts, as 'luaO_str2num'
@@ -259,9 +229,8 @@ static int read_numeral (LexState *ls, SemInfo *seminfo) {
     else break;
   }
   save(ls, '\0');
-  buffreplace(ls, '.', ls->decpoint);  /* follow locale for decimal point */
   if (luaO_str2num(luaZ_buffer(ls->buff), &obj) == 0)  /* format error? */
-    trydecpoint(ls, &obj); /* try to update decimal point separator */
+    lexerror(ls, "malformed number", TK_FLT);
   if (ttisinteger(&obj)) {
     seminfo->i = ivalue(&obj);
     return TK_INT;
diff --git a/lua/llex.h b/lua/llex.h
index afb40b5..2363d87 100644
--- a/lua/llex.h
+++ b/lua/llex.h
@@ -1,5 +1,5 @@
 /*
-** $Id: llex.h,v 1.78 2014/10/29 15:38:24 roberto Exp $
+** $Id: llex.h,v 1.79 2016/05/02 14:02:12 roberto Exp $
 ** Lexical Analyzer
 ** See Copyright Notice in lua.h
 */
@@ -69,7 +69,6 @@ typedef struct LexState {
   struct Dyndata *dyd;  /* dynamic structures used by the parser */
   TString *source;  /* current source name */
   TString *envn;  /* environment variable name */
-  char decpoint;  /* locale decimal point */
 } LexState;
 
 
diff --git a/lua/lobject.c b/lua/lobject.c
index e24723f..a44b385 100644
--- a/lua/lobject.c
+++ b/lua/lobject.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lobject.c,v 2.108 2015/11/02 16:09:30 roberto Exp $
+** $Id: lobject.c,v 2.111 2016/05/20 14:07:48 roberto Exp $
 ** Some generic functions over Lua objects
 ** See Copyright Notice in lua.h
 */
@@ -243,20 +243,59 @@ static lua_Number lua_strx2number (const char *s, char **endptr) {
 /* }====================================================== */
 
 
-static const char *l_str2d (const char *s, lua_Number *result) {
+/* maximum length of a numeral */
+#if !defined (L_MAXLENNUM)
+#define L_MAXLENNUM	200
+#endif
+
+static const char *l_str2dloc (const char *s, lua_Number *result, int mode) {
   char *endptr;
-  if (strpbrk(s, "nN"))  /* reject 'inf' and 'nan' */
-    return NULL;
-  else if (strpbrk(s, "xX"))  /* hex? */
-    *result = lua_strx2number(s, &endptr);
-  else
-    *result = lua_str2number(s, &endptr);
-  if (endptr == s) return NULL;  /* nothing recognized */
-  while (lisspace(cast_uchar(*endptr))) endptr++;
-  return (*endptr == '\0' ? endptr : NULL);  /* OK if no trailing characters */
+  *result = (mode == 'x') ? lua_strx2number(s, &endptr)  /* try to convert */
+                          : lua_str2number(s, &endptr);
+  if (endptr == s) return NULL;  /* nothing recognized? */
+  while (lisspace(cast_uchar(*endptr))) endptr++;  /* skip trailing spaces */
+  return (*endptr == '\0') ? endptr : NULL;  /* OK if no trailing characters */
 }
 
 
+/*
+** Convert string 's' to a Lua number (put in 'result'). Return NULL
+** on fail or the address of the ending '\0' on success.
+** 'pmode' points to (and 'mode' contains) special things in the string:
+** - 'x'/'X' means an hexadecimal numeral
+** - 'n'/'N' means 'inf' or 'nan' (which should be rejected)
+** - '.' just optimizes the search for the common case (nothing special)
+** This function accepts both the current locale or a dot as the radix
+** mark. If the convertion fails, it may mean number has a dot but
+** locale accepts something else. In that case, the code copies 's'
+** to a buffer (because 's' is read-only), changes the dot to the
+** current locale radix mark, and tries to convert again.
+*/
+static const char *l_str2d (const char *s, lua_Number *result) {
+  const char *endptr;
+  const char *pmode = strpbrk(s, ".xXnN");
+  int mode = pmode ? ltolower(cast_uchar(*pmode)) : 0;
+  if (mode == 'n')  /* reject 'inf' and 'nan' */
+    return NULL;
+  endptr = l_str2dloc(s, result, mode);  /* try to convert */
+  if (endptr == NULL) {  /* failed? may be a different locale */
+    char buff[L_MAXLENNUM + 1];
+    char *pdot = strchr(s, '.');
+    if (strlen(s) > L_MAXLENNUM || pdot == NULL)
+      return NULL;  /* string too long or no dot; fail */
+    strcpy(buff, s);  /* copy string to buffer */
+    buff[pdot - s] = lua_getlocaledecpoint();  /* correct decimal point */
+    endptr = l_str2dloc(buff, result, mode);  /* try again */
+    if (endptr != NULL)
+      endptr = s + (endptr - buff);  /* make relative to 's' */
+  }
+  return endptr;
+}
+
+
+#define MAXBY10		cast(lua_Unsigned, LUA_MAXINTEGER / 10)
+#define MAXLASTD	cast_int(LUA_MAXINTEGER % 10)
+
 static const char *l_str2int (const char *s, lua_Integer *result) {
   lua_Unsigned a = 0;
   int empty = 1;
@@ -273,7 +312,10 @@ static const char *l_str2int (const char *s, lua_Integer *result) {
   }
   else {  /* decimal */
     for (; lisdigit(cast_uchar(*s)); s++) {
-      a = a * 10 + *s - '0';
+      int d = *s - '0';
+      if (a >= MAXBY10 && (a > MAXBY10 || d > MAXLASTD + neg))  /* overflow? */
+        return NULL;  /* do not accept it (as integer) */
+      a = a * 10 + d;
       empty = 0;
     }
   }
@@ -351,8 +393,10 @@ static void pushstr (lua_State *L, const char *str, size_t l) {
 }
 
 
-/* this function handles only '%d', '%c', '%f', '%p', and '%s' 
-   conventional formats, plus Lua-specific '%I' and '%U' */
+/*
+** this function handles only '%d', '%c', '%f', '%p', and '%s' 
+   conventional formats, plus Lua-specific '%I' and '%U'
+*/
 const char *luaO_pushvfstring (lua_State *L, const char *fmt, va_list argp) {
   int n = 0;
   for (;;) {
@@ -360,13 +404,13 @@ const char *luaO_pushvfstring (lua_State *L, const char *fmt, va_list argp) {
     if (e == NULL) break;
     pushstr(L, fmt, e - fmt);
     switch (*(e+1)) {
-      case 's': {
+      case 's': {  /* zero-terminated string */
         const char *s = va_arg(argp, char *);
         if (s == NULL) s = "(null)";
         pushstr(L, s, strlen(s));
         break;
       }
-      case 'c': {
+      case 'c': {  /* an 'int' as a character */
         char buff = cast(char, va_arg(argp, int));
         if (lisprint(cast_uchar(buff)))
           pushstr(L, &buff, 1);
@@ -374,28 +418,28 @@ const char *luaO_pushvfstring (lua_State *L, const char *fmt, va_list argp) {
           luaO_pushfstring(L, "<\\%d>", cast_uchar(buff));
         break;
       }
-      case 'd': {
+      case 'd': {  /* an 'int' */
         setivalue(L->top, va_arg(argp, int));
         goto top2str;
       }
-      case 'I': {
+      case 'I': {  /* a 'lua_Integer' */
         setivalue(L->top, cast(lua_Integer, va_arg(argp, l_uacInt)));
         goto top2str;
       }
-      case 'f': {
+      case 'f': {  /* a 'lua_Number' */
         setfltvalue(L->top, cast_num(va_arg(argp, l_uacNumber)));
-      top2str:
+      top2str:  /* convert the top element to a string */
         luaD_inctop(L);
         luaO_tostring(L, L->top - 1);
         break;
       }
-      case 'p': {
+      case 'p': {  /* a pointer */
         char buff[4*sizeof(void *) + 8]; /* should be enough space for a '%p' */
         int l = l_sprintf(buff, sizeof(buff), "%p", va_arg(argp, void *));
         pushstr(L, buff, l);
         break;
       }
-      case 'U': {
+      case 'U': {  /* an 'int' as a UTF-8 sequence */
         char buff[UTF8BUFFSZ];
         int l = luaO_utf8esc(buff, cast(long, va_arg(argp, long)));
         pushstr(L, buff + UTF8BUFFSZ - l, l);
diff --git a/lua/loslib.c b/lua/loslib.c
index 7dae533..4810655 100644
--- a/lua/loslib.c
+++ b/lua/loslib.c
@@ -1,5 +1,5 @@
 /*
-** $Id: loslib.c,v 1.60 2015/11/19 19:16:22 roberto Exp $
+** $Id: loslib.c,v 1.64 2016/04/18 13:06:55 roberto Exp $
 ** Standard Operating System library
 ** See Copyright Notice in lua.h
 */
@@ -24,18 +24,29 @@
 
 /*
 ** {==================================================================
-** list of valid conversion specifiers for the 'strftime' function
+** List of valid conversion specifiers for the 'strftime' function;
+** options are grouped by length; group of length 2 start with '||'.
 ** ===================================================================
 */
 #if !defined(LUA_STRFTIMEOPTIONS)	/* { */
 
-#if defined(LUA_USE_C89)
-#define LUA_STRFTIMEOPTIONS	{ "aAbBcdHIjmMpSUwWxXyYz%", "" }
+/* options for ANSI C 89 */
+#define L_STRFTIMEC89		"aAbBcdHIjmMpSUwWxXyYZ%"
+
+/* options for ISO C 99 and POSIX */
+#define L_STRFTIMEC99 "aAbBcCdDeFgGhHIjmMnprRStTuUVwWxXyYzZ%" \
+	"||" "EcECExEXEyEY" "OdOeOHOIOmOMOSOuOUOVOwOWOy"
+
+/* options for Windows */
+#define L_STRFTIMEWIN "aAbBcdHIjmMpSUwWxXyYzZ%" \
+	"||" "#c#x#d#H#I#j#m#M#S#U#w#W#y#Y"
+
+#if defined(LUA_USE_WINDOWS)
+#define LUA_STRFTIMEOPTIONS	L_STRFTIMEWIN
+#elif defined(LUA_USE_C89)
+#define LUA_STRFTIMEOPTIONS	L_STRFTIMEC89
 #else  /* C99 specification */
-#define LUA_STRFTIMEOPTIONS \
-	{ "aAbBcCdDeFgGhHIjmMnprRStTuUVwWxXyYzZ%", "", \
-	  "E", "cCxXyY",  \
-	  "O", "deHImMSuUVwWy" }
+#define LUA_STRFTIMEOPTIONS	L_STRFTIMEC99
 #endif
 
 #endif					/* } */
@@ -195,6 +206,23 @@ static void setboolfield (lua_State *L, const char *key, int value) {
   lua_setfield(L, -2, key);
 }
 
+
+/*
+** Set all fields from structure 'tm' in the table on top of the stack
+*/
+static void setallfields (lua_State *L, struct tm *stm) {
+  setfield(L, "sec", stm->tm_sec);
+  setfield(L, "min", stm->tm_min);
+  setfield(L, "hour", stm->tm_hour);
+  setfield(L, "day", stm->tm_mday);
+  setfield(L, "month", stm->tm_mon + 1);
+  setfield(L, "year", stm->tm_year + 1900);
+  setfield(L, "wday", stm->tm_wday + 1);
+  setfield(L, "yday", stm->tm_yday + 1);
+  setboolfield(L, "isdst", stm->tm_isdst);
+}
+
+
 static int getboolfield (lua_State *L, const char *key) {
   int res;
   res = (lua_getfield(L, -1, key) == LUA_TNIL) ? -1 : lua_toboolean(L, -1);
@@ -210,18 +238,18 @@ static int getboolfield (lua_State *L, const char *key) {
 
 static int getfield (lua_State *L, const char *key, int d, int delta) {
   int isnum;
-  int t = lua_getfield(L, -1, key);
+  int t = lua_getfield(L, -1, key);  /* get field and its type */
   lua_Integer res = lua_tointegerx(L, -1, &isnum);
-  if (!isnum) {  /* field is not a number? */
+  if (!isnum) {  /* field is not an integer? */
     if (t != LUA_TNIL)  /* some other value? */
-      return luaL_error(L, "field '%s' not an integer", key);
+      return luaL_error(L, "field '%s' is not an integer", key);
     else if (d < 0)  /* absent field; no default? */
       return luaL_error(L, "field '%s' missing in date table", key);
     res = d;
   }
   else {
     if (!(-L_MAXDATEFIELD <= res && res <= L_MAXDATEFIELD))
-      return luaL_error(L, "field '%s' out-of-bounds", key);
+      return luaL_error(L, "field '%s' is out-of-bound", key);
     res -= delta;
   }
   lua_pop(L, 1);
@@ -230,21 +258,15 @@ static int getfield (lua_State *L, const char *key, int d, int delta) {
 
 
 static const char *checkoption (lua_State *L, const char *conv, char *buff) {
-  static const char *const options[] = LUA_STRFTIMEOPTIONS;
-  unsigned int i;
-  for (i = 0; i < sizeof(options)/sizeof(options[0]); i += 2) {
-    if (*conv != '\0' && strchr(options[i], *conv) != NULL) {
-      buff[1] = *conv;
-      if (*options[i + 1] == '\0') {  /* one-char conversion specifier? */
-        buff[2] = '\0';  /* end buffer */
-        return conv + 1;
-      }
-      else if (*(conv + 1) != '\0' &&
-               strchr(options[i + 1], *(conv + 1)) != NULL) {
-        buff[2] = *(conv + 1);  /* valid two-char conversion specifier */
-        buff[3] = '\0';  /* end buffer */
-        return conv + 2;
-      }
+  const char *option;
+  int oplen = 1;
+  for (option = LUA_STRFTIMEOPTIONS; *option != '\0'; option += oplen) {
+    if (*option == '|')  /* next block? */
+      oplen++;  /* next length */
+    else if (memcmp(conv, option, oplen) == 0) {  /* match? */
+      memcpy(buff, conv, oplen);  /* copy valid option to buffer */
+      buff[oplen] = '\0';
+      return conv + oplen;  /* return next item */
     }
   }
   luaL_argerror(L, 1,
@@ -271,18 +293,10 @@ static int os_date (lua_State *L) {
     luaL_error(L, "time result cannot be represented in this installation");
   if (strcmp(s, "*t") == 0) {
     lua_createtable(L, 0, 9);  /* 9 = number of fields */
-    setfield(L, "sec", stm->tm_sec);
-    setfield(L, "min", stm->tm_min);
-    setfield(L, "hour", stm->tm_hour);
-    setfield(L, "day", stm->tm_mday);
-    setfield(L, "month", stm->tm_mon+1);
-    setfield(L, "year", stm->tm_year+1900);
-    setfield(L, "wday", stm->tm_wday+1);
-    setfield(L, "yday", stm->tm_yday+1);
-    setboolfield(L, "isdst", stm->tm_isdst);
+    setallfields(L, stm);
   }
   else {
-    char cc[4];
+    char cc[4];  /* buffer for individual conversion specifiers */
     luaL_Buffer b;
     cc[0] = '%';
     luaL_buffinit(L, &b);
@@ -292,7 +306,7 @@ static int os_date (lua_State *L) {
       else {
         size_t reslen;
         char *buff = luaL_prepbuffsize(&b, SIZETIMEFMT);
-        s = checkoption(L, s + 1, cc);
+        s = checkoption(L, s + 1, cc + 1);  /* copy specifier to 'cc' */
         reslen = strftime(buff, SIZETIMEFMT, cc, stm);
         luaL_addsize(&b, reslen);
       }
@@ -319,6 +333,7 @@ static int os_time (lua_State *L) {
     ts.tm_year = getfield(L, "year", -1, 1900);
     ts.tm_isdst = getboolfield(L, "isdst");
     t = mktime(&ts);
+    setallfields(L, &ts);  /* update fields with normalized values */
   }
   if (t != (time_t)(l_timet)t || t == (time_t)(-1))
     luaL_error(L, "time result cannot be represented in this installation");
diff --git a/lua/lparser.c b/lua/lparser.c
index 282a6b1..22530a5 100644
--- a/lua/lparser.c
+++ b/lua/lparser.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lparser.c,v 2.149 2015/11/02 16:09:30 roberto Exp $
+** $Id: lparser.c,v 2.153 2016/05/13 19:10:16 roberto Exp $
 ** Lua Parser
 ** See Copyright Notice in lua.h
 */
@@ -164,7 +164,8 @@ static int registerlocalvar (LexState *ls, TString *varname) {
   int oldsize = f->sizelocvars;
   luaM_growvector(ls->L, f->locvars, fs->nlocvars, f->sizelocvars,
                   LocVar, SHRT_MAX, "local variables");
-  while (oldsize < f->sizelocvars) f->locvars[oldsize++].varname = NULL;
+  while (oldsize < f->sizelocvars)
+    f->locvars[oldsize++].varname = NULL;
   f->locvars[fs->nlocvars].varname = varname;
   luaC_objbarrier(ls->L, f, varname);
   return fs->nlocvars++;
@@ -230,7 +231,8 @@ static int newupvalue (FuncState *fs, TString *name, expdesc *v) {
   checklimit(fs, fs->nups + 1, MAXUPVAL, "upvalues");
   luaM_growvector(fs->ls->L, f->upvalues, fs->nups, f->sizeupvalues,
                   Upvaldesc, MAXUPVAL, "upvalues");
-  while (oldsize < f->sizeupvalues) f->upvalues[oldsize++].name = NULL;
+  while (oldsize < f->sizeupvalues)
+    f->upvalues[oldsize++].name = NULL;
   f->upvalues[fs->nups].instack = (v->k == VLOCAL);
   f->upvalues[fs->nups].idx = cast_byte(v->u.info);
   f->upvalues[fs->nups].name = name;
@@ -255,7 +257,8 @@ static int searchvar (FuncState *fs, TString *n) {
 */
 static void markupval (FuncState *fs, int level) {
   BlockCnt *bl = fs->bl;
-  while (bl->nactvar > level) bl = bl->previous;
+  while (bl->nactvar > level)
+    bl = bl->previous;
   bl->upval = 1;
 }
 
@@ -264,27 +267,26 @@ static void markupval (FuncState *fs, int level) {
   Find variable with given name 'n'. If it is an upvalue, add this
   upvalue into all intermediate functions.
 */
-static int singlevaraux (FuncState *fs, TString *n, expdesc *var, int base) {
+static void singlevaraux (FuncState *fs, TString *n, expdesc *var, int base) {
   if (fs == NULL)  /* no more levels? */
-    return VVOID;  /* default is global */
+    init_exp(var, VVOID, 0);  /* default is global */
   else {
     int v = searchvar(fs, n);  /* look up locals at current level */
     if (v >= 0) {  /* found? */
       init_exp(var, VLOCAL, v);  /* variable is local */
       if (!base)
         markupval(fs, v);  /* local will be used as an upval */
-      return VLOCAL;
     }
     else {  /* not found as local at current level; try upvalues */
       int idx = searchupvalue(fs, n);  /* try existing upvalues */
       if (idx < 0) {  /* not found? */
-        if (singlevaraux(fs->prev, n, var, 0) == VVOID) /* try upper levels */
-          return VVOID;  /* not found; is a global */
+        singlevaraux(fs->prev, n, var, 0);  /* try upper levels */
+        if (var->k == VVOID)  /* not found? */
+          return;  /* it is a global */
         /* else was LOCAL or UPVAL */
         idx  = newupvalue(fs, n, var);  /* will be a new upvalue */
       }
-      init_exp(var, VUPVAL, idx);
-      return VUPVAL;
+      init_exp(var, VUPVAL, idx);  /* new or old upvalue */
     }
   }
 }
@@ -293,10 +295,11 @@ static int singlevaraux (FuncState *fs, TString *n, expdesc *var, int base) {
 static void singlevar (LexState *ls, expdesc *var) {
   TString *varname = str_checkname(ls);
   FuncState *fs = ls->fs;
-  if (singlevaraux(fs, varname, var, 1) == VVOID) {  /* global name? */
+  singlevaraux(fs, varname, var, 1);
+  if (var->k == VVOID) {  /* global name? */
     expdesc key;
     singlevaraux(fs, ls->envn, var, 1);  /* get environment variable */
-    lua_assert(var->k == VLOCAL || var->k == VUPVAL);
+    lua_assert(var->k != VVOID);  /* this one must exist */
     codestring(ls, &key, varname);  /* key is variable name */
     luaK_indexed(fs, var, &key);  /* env[varname] */
   }
@@ -499,7 +502,8 @@ static Proto *addprototype (LexState *ls) {
   if (fs->np >= f->sizep) {
     int oldsize = f->sizep;
     luaM_growvector(L, f->p, fs->np, f->sizep, Proto *, MAXARG_Bx, "functions");
-    while (oldsize < f->sizep) f->p[oldsize++] = NULL;
+    while (oldsize < f->sizep)
+      f->p[oldsize++] = NULL;
   }
   f->p[fs->np++] = clp = luaF_newproto(L);
   luaC_objbarrier(L, f, clp);
@@ -1226,7 +1230,7 @@ static void labelstat (LexState *ls, TString *label, int line) {
   checkrepeated(fs, ll, label);  /* check for repeated labels */
   checknext(ls, TK_DBCOLON);  /* skip double colon */
   /* create new entry for this label */
-  l = newlabelentry(ls, ll, label, line, fs->pc);
+  l = newlabelentry(ls, ll, label, line, luaK_getlabel(fs));
   skipnoopstat(ls);  /* skip other no-op statements */
   if (block_follow(ls, 0)) {  /* label is last no-op statement in the block? */
     /* assume that locals are already out of scope */
@@ -1494,7 +1498,7 @@ static void exprstat (LexState *ls) {
   }
   else {  /* stat -> func */
     check_condition(ls, v.v.k == VCALL, "syntax error");
-    SETARG_C(getcode(fs, &v.v), 1);  /* call statement uses no results */
+    SETARG_C(getinstruction(fs, &v.v), 1);  /* call statement uses no results */
   }
 }
 
@@ -1511,8 +1515,8 @@ static void retstat (LexState *ls) {
     if (hasmultret(e.k)) {
       luaK_setmultret(fs, &e);
       if (e.k == VCALL && nret == 1) {  /* tail call? */
-        SET_OPCODE(getcode(fs,&e), OP_TAILCALL);
-        lua_assert(GETARG_A(getcode(fs,&e)) == fs->nactvar);
+        SET_OPCODE(getinstruction(fs,&e), OP_TAILCALL);
+        lua_assert(GETARG_A(getinstruction(fs,&e)) == fs->nactvar);
       }
       first = fs->nactvar;
       nret = LUA_MULTRET;  /* return all values */
diff --git a/lua/lparser.h b/lua/lparser.h
index 62c50ca..02e9b03 100644
--- a/lua/lparser.h
+++ b/lua/lparser.h
@@ -1,5 +1,5 @@
 /*
-** $Id: lparser.h,v 1.74 2014/10/25 11:50:46 roberto Exp $
+** $Id: lparser.h,v 1.76 2015/12/30 18:16:13 roberto Exp $
 ** Lua Parser
 ** See Copyright Notice in lua.h
 */
@@ -13,25 +13,38 @@
 
 
 /*
-** Expression descriptor
+** Expression and variable descriptor.
+** Code generation for variables and expressions can be delayed to allow
+** optimizations; An 'expdesc' structure describes a potentially-delayed
+** variable/expression. It has a description of its "main" value plus a
+** list of conditional jumps that can also produce its value (generated
+** by short-circuit operators 'and'/'or').
 */
 
+/* kinds of variables/expressions */
 typedef enum {
-  VVOID,	/* no value */
-  VNIL,
-  VTRUE,
-  VFALSE,
-  VK,		/* info = index of constant in 'k' */
-  VKFLT,	/* nval = numerical float value */
-  VKINT,	/* nval = numerical integer value */
-  VNONRELOC,	/* info = result register */
-  VLOCAL,	/* info = local register */
-  VUPVAL,       /* info = index of upvalue in 'upvalues' */
-  VINDEXED,	/* t = table register/upvalue; idx = index R/K */
-  VJMP,		/* info = instruction pc */
-  VRELOCABLE,	/* info = instruction pc */
-  VCALL,	/* info = instruction pc */
-  VVARARG	/* info = instruction pc */
+  VVOID,  /* when 'expdesc' describes the last expression a list,
+             this kind means an empty list (so, no expression) */
+  VNIL,  /* constant nil */
+  VTRUE,  /* constant true */
+  VFALSE,  /* constant false */
+  VK,  /* constant in 'k'; info = index of constant in 'k' */
+  VKFLT,  /* floating constant; nval = numerical float value */
+  VKINT,  /* integer constant; nval = numerical integer value */
+  VNONRELOC,  /* expression has its value in a fixed register;
+                 info = result register */
+  VLOCAL,  /* local variable; info = local register */
+  VUPVAL,  /* upvalue variable; info = index of upvalue in 'upvalues' */
+  VINDEXED,  /* indexed variable;
+                ind.vt = whether 't' is register or upvalue;
+                ind.t = table register or upvalue;
+                ind.idx = key's R/K index */
+  VJMP,  /* expression is a test/comparison;
+            info = pc of corresponding jump instruction */
+  VRELOCABLE,  /* expression can put result in any register;
+                  info = instruction pc */
+  VCALL,  /* expression is a function call; info = instruction pc */
+  VVARARG  /* vararg expression; info = instruction pc */
 } expkind;
 
 
@@ -41,14 +54,14 @@ typedef enum {
 typedef struct expdesc {
   expkind k;
   union {
+    lua_Integer ival;    /* for VKINT */
+    lua_Number nval;  /* for VKFLT */
+    int info;  /* for generic use */
     struct {  /* for indexed variables (VINDEXED) */
       short idx;  /* index (R/K) */
       lu_byte t;  /* table (register or upvalue) */
       lu_byte vt;  /* whether 't' is register (VLOCAL) or upvalue (VUPVAL) */
     } ind;
-    int info;  /* for generic use */
-    lua_Number nval;  /* for VKFLT */
-    lua_Integer ival;    /* for VKINT */
   } u;
   int t;  /* patch list of 'exit when true' */
   int f;  /* patch list of 'exit when false' */
diff --git a/lua/lstate.h b/lua/lstate.h
index 65c914d..b3033be 100644
--- a/lua/lstate.h
+++ b/lua/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
@@ -162,14 +171,14 @@ 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;
   int hookcount;
   unsigned short nny;  /* number of non-yieldable calls in stack */
   unsigned short nCcalls;  /* number of nested C calls */
-  lu_byte hookmask;
+  l_signalT hookmask;
   lu_byte allowhook;
 };
 
diff --git a/lua/lstrlib.c b/lua/lstrlib.c
index fe30e34..12264f8 100644
--- a/lua/lstrlib.c
+++ b/lua/lstrlib.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lstrlib.c,v 1.239 2015/11/25 16:28:17 roberto Exp $
+** $Id: lstrlib.c,v 1.251 2016/05/20 14:13:21 roberto Exp $
 ** Standard library for string operations and pattern-matching
 ** See Copyright Notice in lua.h
 */
@@ -13,6 +13,7 @@
 #include <ctype.h>
 #include <float.h>
 #include <limits.h>
+#include <locale.h>
 #include <stddef.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -26,7 +27,8 @@
 
 /*
 ** maximum number of captures that a pattern can do during
-** pattern-matching. This limit is arbitrary.
+** pattern-matching. This limit is arbitrary, but must fit in
+** an unsigned char.
 */
 #if !defined(LUA_MAXCAPTURES)
 #define LUA_MAXCAPTURES		32
@@ -214,9 +216,8 @@ typedef struct MatchState {
   const char *src_end;  /* end ('\0') of source string */
   const char *p_end;  /* end ('\0') of pattern */
   lua_State *L;
-  size_t nrep;  /* limit to avoid non-linear complexity */
   int matchdepth;  /* control for recursive depth (to avoid C stack overflow) */
-  int level;  /* total number of captures (finished or unfinished) */
+  unsigned char level;  /* total number of captures (finished or unfinished) */
   struct {
     const char *init;
     ptrdiff_t len;
@@ -234,17 +235,6 @@ static const char *match (MatchState *ms, const char *s, const char *p);
 #endif
 
 
-/*
-** parameters to control the maximum number of operators handled in
-** a match (to avoid non-linear complexity). The maximum will be:
-** (subject length) * A_REPS + B_REPS
-*/
-#if !defined(A_REPS)
-#define A_REPS		4
-#define B_REPS		100000
-#endif
-
-
 #define L_ESC		'%'
 #define SPECIALS	"^$*+?.([%-"
 
@@ -502,8 +492,6 @@ static const char *match (MatchState *ms, const char *s, const char *p) {
             s = NULL;  /* fail */
         }
         else {  /* matched once */
-          if (ms->nrep-- == 0)
-            luaL_error(ms->L, "pattern too complex");
           switch (*ep) {  /* handle optional suffix */
             case '?': {  /* optional */
               const char *res;
@@ -607,10 +595,6 @@ static void prepstate (MatchState *ms, lua_State *L,
   ms->src_init = s;
   ms->src_end = s + ls;
   ms->p_end = p + lp;
-  if (ls < (MAX_SIZET - B_REPS) / A_REPS)
-    ms->nrep = A_REPS * ls + B_REPS;
-  else  /* overflow (very long subject) */
-    ms->nrep = MAX_SIZET;  /* no limit */
 }
 
 
@@ -681,6 +665,7 @@ static int str_match (lua_State *L) {
 typedef struct GMatchState {
   const char *src;  /* current position */
   const char *p;  /* pattern */
+  const char *lastmatch;  /* end of last match */
   MatchState ms;  /* match state */
 } GMatchState;
 
@@ -688,14 +673,12 @@ typedef struct GMatchState {
 static int gmatch_aux (lua_State *L) {
   GMatchState *gm = (GMatchState *)lua_touserdata(L, lua_upvalueindex(3));
   const char *src;
+  gm->ms.L = L;
   for (src = gm->src; src <= gm->ms.src_end; src++) {
     const char *e;
     reprepstate(&gm->ms);
-    if ((e = match(&gm->ms, src, gm->p)) != NULL) {
-      if (e == src)  /* empty match? */
-        gm->src =src + 1;  /* go at least one position */
-      else
-        gm->src = e;
+    if ((e = match(&gm->ms, src, gm->p)) != NULL && e != gm->lastmatch) {
+      gm->src = gm->lastmatch = e;
       return push_captures(&gm->ms, src, e);
     }
   }
@@ -711,7 +694,7 @@ static int gmatch (lua_State *L) {
   lua_settop(L, 2);  /* keep them on closure to avoid being collected */
   gm = (GMatchState *)lua_newuserdata(L, sizeof(GMatchState));
   prepstate(&gm->ms, L, s, ls, p, lp);
-  gm->src = s; gm->p = p;
+  gm->src = s; gm->p = p; gm->lastmatch = NULL;
   lua_pushcclosure(L, gmatch_aux, 3);
   return 1;
 }
@@ -778,12 +761,13 @@ static void add_value (MatchState *ms, luaL_Buffer *b, const char *s,
 
 static int str_gsub (lua_State *L) {
   size_t srcl, lp;
-  const char *src = luaL_checklstring(L, 1, &srcl);
-  const char *p = luaL_checklstring(L, 2, &lp);
-  int tr = lua_type(L, 3);
-  lua_Integer max_s = luaL_optinteger(L, 4, srcl + 1);
+  const char *src = luaL_checklstring(L, 1, &srcl);  /* subject */
+  const char *p = luaL_checklstring(L, 2, &lp);  /* pattern */
+  const char *lastmatch = NULL;  /* end of last match */
+  int tr = lua_type(L, 3);  /* replacement type */
+  lua_Integer max_s = luaL_optinteger(L, 4, srcl + 1);  /* max replacements */
   int anchor = (*p == '^');
-  lua_Integer n = 0;
+  lua_Integer n = 0;  /* replacement count */
   MatchState ms;
   luaL_Buffer b;
   luaL_argcheck(L, tr == LUA_TNUMBER || tr == LUA_TSTRING ||
@@ -796,16 +780,15 @@ static int str_gsub (lua_State *L) {
   prepstate(&ms, L, src, srcl, p, lp);
   while (n < max_s) {
     const char *e;
-    reprepstate(&ms);
-    if ((e = match(&ms, src, p)) != NULL) {
+    reprepstate(&ms);  /* (re)prepare state for new match */
+    if ((e = match(&ms, src, p)) != NULL && e != lastmatch) {  /* match? */
       n++;
-      add_value(&ms, &b, src, e, tr);
+      add_value(&ms, &b, src, e, tr);  /* add replacement to buffer */
+      src = lastmatch = e;
     }
-    if (e && e>src) /* non empty match? */
-      src = e;  /* skip it */
-    else if (src < ms.src_end)
+    else if (src < ms.src_end)  /* otherwise, skip one character */
       luaL_addchar(&b, *src++);
-    else break;
+    else break;  /* end of subject */
     if (anchor) break;
   }
   luaL_addlstring(&b, src, ms.src_end-src);
@@ -830,7 +813,6 @@ static int str_gsub (lua_State *L) {
 ** Hexadecimal floating-point formatter
 */
 
-#include <locale.h>
 #include <math.h>
 
 #define SIZELENMOD	(sizeof(LUA_NUMBER_FRMLEN)/sizeof(char))
@@ -922,16 +904,14 @@ static int lua_number2strx (lua_State *L, char *buff, int sz,
 #define MAX_FORMAT	32
 
 
-static void addquoted (lua_State *L, luaL_Buffer *b, int arg) {
-  size_t l;
-  const char *s = luaL_checklstring(L, arg, &l);
+static void addquoted (luaL_Buffer *b, const char *s, size_t len) {
   luaL_addchar(b, '"');
-  while (l--) {
+  while (len--) {
     if (*s == '"' || *s == '\\' || *s == '\n') {
       luaL_addchar(b, '\\');
       luaL_addchar(b, *s);
     }
-    else if (*s == '\0' || iscntrl(uchar(*s))) {
+    else if (iscntrl(uchar(*s))) {
       char buff[10];
       if (!isdigit(uchar(*(s+1))))
         l_sprintf(buff, sizeof(buff), "\\%d", (int)uchar(*s));
@@ -946,6 +926,57 @@ static void addquoted (lua_State *L, luaL_Buffer *b, int arg) {
   luaL_addchar(b, '"');
 }
 
+
+/*
+** Ensures the 'buff' string uses a dot as the radix character.
+*/
+static void checkdp (char *buff, int nb) {
+  if (memchr(buff, '.', nb) == NULL) {  /* no dot? */
+    char point = lua_getlocaledecpoint();  /* try locale point */
+    char *ppoint = memchr(buff, point, nb);
+    if (ppoint) *ppoint = '.';  /* change it to a dot */
+  }
+}
+
+
+static void addliteral (lua_State *L, luaL_Buffer *b, int arg) {
+  switch (lua_type(L, arg)) {
+    case LUA_TSTRING: {
+      size_t len;
+      const char *s = lua_tolstring(L, arg, &len);
+      addquoted(b, s, len);
+      break;
+    }
+    case LUA_TNUMBER: {
+      char *buff = luaL_prepbuffsize(b, MAX_ITEM);
+      int nb;
+      if (!lua_isinteger(L, arg)) {  /* float? */
+        lua_Number n = lua_tonumber(L, arg);  /* write as hexa ('%a') */
+        nb = lua_number2strx(L, buff, MAX_ITEM, "%" LUA_NUMBER_FRMLEN "a", n);
+        checkdp(buff, nb);  /* ensure it uses a dot */
+      }
+      else {  /* integers */
+        lua_Integer n = lua_tointeger(L, arg);
+        const char *format = (n == LUA_MININTEGER)  /* corner case? */
+                           ? "0x%" LUA_INTEGER_FRMLEN "x"  /* use hexa */
+                           : LUA_INTEGER_FMT;  /* else use default format */
+        nb = l_sprintf(buff, MAX_ITEM, format, n);
+      }
+      luaL_addsize(b, nb);
+      break;
+    }
+    case LUA_TNIL: case LUA_TBOOLEAN: {
+      luaL_tolstring(L, arg, NULL);
+      luaL_addvalue(b);
+      break;
+    }
+    default: {
+      luaL_argerror(L, arg, "value has no literal form");
+    }
+  }
+}
+
+
 static const char *scanformat (lua_State *L, const char *strfrmt, char *form) {
   const char *p = strfrmt;
   while (*p != '\0' && strchr(FLAGS, *p) != NULL) p++;  /* skip flags */
@@ -1025,7 +1056,7 @@ static int str_format (lua_State *L) {
           break;
         }
         case 'q': {
-          addquoted(L, &b, arg);
+          addliteral(L, &b, arg);
           break;
         }
         case 's': {
@@ -1070,8 +1101,8 @@ static int str_format (lua_State *L) {
 
 
 /* value used for padding */
-#if !defined(LUA_PACKPADBYTE)
-#define LUA_PACKPADBYTE		0x00
+#if !defined(LUAL_PACKPADBYTE)
+#define LUAL_PACKPADBYTE		0x00
 #endif
 
 /* maximum size for the binary representation of an integer */
@@ -1308,7 +1339,7 @@ static int str_pack (lua_State *L) {
     KOption opt = getdetails(&h, totalsize, &fmt, &size, &ntoalign);
     totalsize += ntoalign + size;
     while (ntoalign-- > 0)
-     luaL_addchar(&b, LUA_PACKPADBYTE);  /* fill alignment */
+     luaL_addchar(&b, LUAL_PACKPADBYTE);  /* fill alignment */
     arg++;
     switch (opt) {
       case Kint: {  /* signed integers */
@@ -1343,13 +1374,11 @@ static int str_pack (lua_State *L) {
       case Kchar: {  /* fixed-size string */
         size_t len;
         const char *s = luaL_checklstring(L, arg, &len);
-        if ((size_t)size <= len)  /* string larger than (or equal to) needed? */
-          luaL_addlstring(&b, s, size);  /* truncate string to asked size */
-        else {  /* string smaller than needed */
-          luaL_addlstring(&b, s, len);  /* add it all */
-          while (len++ < (size_t)size)  /* pad extra space */
-            luaL_addchar(&b, LUA_PACKPADBYTE);
-        }
+        luaL_argcheck(L, len <= (size_t)size, arg,
+                         "string longer than given size");
+        luaL_addlstring(&b, s, len);  /* add string */
+        while (len++ < (size_t)size)  /* pad extra space */
+          luaL_addchar(&b, LUAL_PACKPADBYTE);
         break;
       }
       case Kstring: {  /* strings with length count */
@@ -1372,7 +1401,7 @@ static int str_pack (lua_State *L) {
         totalsize += len + 1;
         break;
       }
-      case Kpadding: luaL_addchar(&b, LUA_PACKPADBYTE);  /* FALLTHROUGH */
+      case Kpadding: luaL_addchar(&b, LUAL_PACKPADBYTE);  /* FALLTHROUGH */
       case Kpaddalign: case Knop:
         arg--;  /* undo increment */
         break;
diff --git a/lua/ltablib.c b/lua/ltablib.c
index b3c9a7c..98b2f87 100644
--- a/lua/ltablib.c
+++ b/lua/ltablib.c
@@ -1,5 +1,5 @@
 /*
-** $Id: ltablib.c,v 1.90 2015/11/25 12:48:57 roberto Exp $
+** $Id: ltablib.c,v 1.93 2016/02/25 19:41:54 roberto Exp $
 ** Library for Table Manipulation
 ** See Copyright Notice in lua.h
 */
@@ -53,7 +53,7 @@ static void checktab (lua_State *L, int arg, int what) {
       lua_pop(L, n);  /* pop metatable and tested metamethods */
     }
     else
-      luaL_argerror(L, arg, "table expected");  /* force an error */
+      luaL_checktype(L, arg, LUA_TTABLE);  /* force an error */
   }
 }
 
@@ -139,7 +139,7 @@ static int tmove (lua_State *L) {
     n = e - f + 1;  /* number of elements to move */
     luaL_argcheck(L, t <= LUA_MAXINTEGER - n + 1, 4,
                   "destination wrap around");
-    if (t > e || t <= f || tt != 1) {
+    if (t > e || t <= f || (tt != 1 && !lua_compare(L, 1, tt, LUA_OPEQ))) {
       for (i = 0; i < n; i++) {
         lua_geti(L, 1, f + i);
         lua_seti(L, tt, t + i);
@@ -152,7 +152,7 @@ static int tmove (lua_State *L) {
       }
     }
   }
-  lua_pushvalue(L, tt);  /* return "to table" */
+  lua_pushvalue(L, tt);  /* return destination table */
   return 1;
 }
 
@@ -172,7 +172,7 @@ static int tconcat (lua_State *L) {
   size_t lsep;
   const char *sep = luaL_optlstring(L, 2, "", &lsep);
   lua_Integer i = luaL_optinteger(L, 3, 1);
-  last = luaL_opt(L, luaL_checkinteger, 4, last);
+  last = luaL_optinteger(L, 4, last);
   luaL_buffinit(L, &b);
   for (; i < last; i++) {
     addfield(L, &b, i);
@@ -232,6 +232,10 @@ static int unpack (lua_State *L) {
 */
 
 
+/* type for array indices */
+typedef unsigned int IdxT;
+
+
 /*
 ** Produce a "random" 'unsigned int' to randomize pivot choice. This
 ** macro is used only when 'sort' detects a big imbalance in the result
@@ -270,7 +274,7 @@ static unsigned int l_randomizePivot (void) {
 #define RANLIMIT	100u
 
 
-static void set2 (lua_State *L, unsigned int i, unsigned int j) {
+static void set2 (lua_State *L, IdxT i, IdxT j) {
   lua_seti(L, 1, i);
   lua_seti(L, 1, j);
 }
@@ -303,10 +307,9 @@ static int sort_comp (lua_State *L, int a, int b) {
 ** Pos-condition: a[lo .. i - 1] <= a[i] == P <= a[i + 1 .. up]
 ** returns 'i'.
 */
-static unsigned int partition (lua_State *L, unsigned int lo,
-                                             unsigned int up) {
-  unsigned int i = lo;  /* will be incremented before first use */
-  unsigned int j = up - 1;  /* will be decremented before first use */
+static IdxT partition (lua_State *L, IdxT lo, IdxT up) {
+  IdxT i = lo;  /* will be incremented before first use */
+  IdxT j = up - 1;  /* will be decremented before first use */
   /* loop invariant: a[lo .. i] <= P <= a[j .. up] */
   for (;;) {
     /* next loop: repeat ++i while a[i] < P */
@@ -340,10 +343,9 @@ static unsigned int partition (lua_State *L, unsigned int lo,
 ** Choose an element in the middle (2nd-3th quarters) of [lo,up]
 ** "randomized" by 'rnd'
 */
-static unsigned int choosePivot (unsigned int lo, unsigned int up,
-                                 unsigned int rnd) {
-  unsigned int r4 = (unsigned int)(up - lo) / 4u;  /* range/4 */
-  unsigned int p = rnd % (r4 * 2) + (lo + r4);
+static IdxT choosePivot (IdxT lo, IdxT up, unsigned int rnd) {
+  IdxT r4 = (up - lo) / 4;  /* range/4 */
+  IdxT p = rnd % (r4 * 2) + (lo + r4);
   lua_assert(lo + r4 <= p && p <= up - r4);
   return p;
 }
@@ -352,11 +354,11 @@ static unsigned int choosePivot (unsigned int lo, unsigned int up,
 /*
 ** QuickSort algorithm (recursive function)
 */
-static void auxsort (lua_State *L, unsigned int lo, unsigned int up,
+static void auxsort (lua_State *L, IdxT lo, IdxT up,
                                    unsigned int rnd) {
   while (lo < up) {  /* loop for tail recursion */
-    unsigned int p;  /* Pivot index */
-    unsigned int n;  /* to be used later */
+    IdxT p;  /* Pivot index */
+    IdxT n;  /* to be used later */
     /* sort elements 'lo', 'p', and 'up' */
     lua_geti(L, 1, lo);
     lua_geti(L, 1, up);
@@ -400,7 +402,7 @@ static void auxsort (lua_State *L, unsigned int lo, unsigned int up,
       n = up - p;  /* size of smaller interval */
       up = p - 1;  /* tail call for [lo .. p - 1]  (lower interval) */
     }
-    if ((up - lo) / 128u > n) /* partition too imbalanced? */
+    if ((up - lo) / 128 > n) /* partition too imbalanced? */
       rnd = l_randomizePivot();  /* try a new randomization */
   }  /* tail call auxsort(L, lo, up, rnd) */
 }
@@ -410,11 +412,10 @@ static int sort (lua_State *L) {
   lua_Integer n = aux_getn(L, 1, TAB_RW);
   if (n > 1) {  /* non-trivial interval? */
     luaL_argcheck(L, n < INT_MAX, 1, "array too big");
-    luaL_checkstack(L, 40, "");  /* assume array is smaller than 2^40 */
     if (!lua_isnoneornil(L, 2))  /* is there a 2nd argument? */
       luaL_checktype(L, 2, LUA_TFUNCTION);  /* must be a function */
     lua_settop(L, 2);  /* make sure there are two arguments */
-    auxsort(L, 1, (unsigned int)n, 0u);
+    auxsort(L, 1, (IdxT)n, 0);
   }
   return 0;
 }
diff --git a/lua/ltm.c b/lua/ltm.c
index 22b4df3..4650cc2 100644
--- a/lua/ltm.c
+++ b/lua/ltm.c
@@ -1,5 +1,5 @@
 /*
-** $Id: ltm.c,v 2.36 2015/11/03 15:47:30 roberto Exp $
+** $Id: ltm.c,v 2.37 2016/02/26 19:20:15 roberto Exp $
 ** Tag methods
 ** See Copyright Notice in lua.h
 */
@@ -83,6 +83,22 @@ const TValue *luaT_gettmbyobj (lua_State *L, const TValue *o, TMS event) {
 }
 
 
+/*
+** Return the name of the type of an object. For tables and userdata
+** with metatable, use their '__name' metafield, if present.
+*/
+const char *luaT_objtypename (lua_State *L, const TValue *o) {
+  Table *mt;
+  if ((ttistable(o) && (mt = hvalue(o)->metatable) != NULL) ||
+      (ttisfulluserdata(o) && (mt = uvalue(o)->metatable) != NULL)) {
+    const TValue *name = luaH_getshortstr(mt, luaS_new(L, "__name"));
+    if (ttisstring(name))  /* is '__name' a string? */
+      return getstr(tsvalue(name));  /* use it as type name */
+  }
+  return ttypename(ttnov(o));  /* else use standard type name */
+}
+
+
 void luaT_callTM (lua_State *L, const TValue *f, const TValue *p1,
                   const TValue *p2, TValue *p3, int hasres) {
   ptrdiff_t result = savestack(L, p3);
diff --git a/lua/ltm.h b/lua/ltm.h
index 180179c..63db726 100644
--- a/lua/ltm.h
+++ b/lua/ltm.h
@@ -1,5 +1,5 @@
 /*
-** $Id: ltm.h,v 2.21 2014/10/25 11:50:46 roberto Exp $
+** $Id: ltm.h,v 2.22 2016/02/26 19:20:15 roberto Exp $
 ** Tag methods
 ** See Copyright Notice in lua.h
 */
@@ -51,11 +51,12 @@ typedef enum {
 #define fasttm(l,et,e)	gfasttm(G(l), et, e)
 
 #define ttypename(x)	luaT_typenames_[(x) + 1]
-#define objtypename(x)	ttypename(ttnov(x))
 
 LUAI_DDEC const char *const luaT_typenames_[LUA_TOTALTAGS];
 
 
+LUAI_FUNC const char *luaT_objtypename (lua_State *L, const TValue *o);
+
 LUAI_FUNC const TValue *luaT_gettm (Table *events, TMS event, TString *ename);
 LUAI_FUNC const TValue *luaT_gettmbyobj (lua_State *L, const TValue *o,
                                                        TMS event);
diff --git a/lua/lua.h b/lua/lua.h
index 06381d7..f78899f 100644
--- a/lua/lua.h
+++ b/lua/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	"Lua " LUA_VERSION_MAJOR "." LUA_VERSION_MINOR
 #define LUA_RELEASE	LUA_VERSION "." LUA_VERSION_RELEASE
-#define LUA_COPYRIGHT	LUA_RELEASE "  Copyright (C) 1994-2015 Lua.org, PUC-Rio"
+#define LUA_COPYRIGHT	LUA_RELEASE "  Copyright (C) 1994-2016 Lua.org, PUC-Rio"
 #define LUA_AUTHORS	"R. Ierusalimschy, L. H. de Figueiredo, W. Celes"
 
 
@@ -361,7 +361,7 @@ LUA_API void      (lua_setallocf) (lua_State *L, lua_Alloc f, void *ud);
 #define lua_pushliteral(L, s)	lua_pushstring(L, "" s)
 
 #define lua_pushglobaltable(L)  \
-	lua_rawgeti(L, LUA_REGISTRYINDEX, LUA_RIDX_GLOBALS)
+	((void)lua_rawgeti(L, LUA_REGISTRYINDEX, LUA_RIDX_GLOBALS))
 
 #define lua_tostring(L,i)	lua_tolstring(L, (i), NULL)
 
@@ -460,7 +460,7 @@ struct lua_Debug {
 
 
 /******************************************************************************
-* 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/lua/luaconf.h b/lua/luaconf.h
index b4ed500..fd447cc 100644
--- a/lua/luaconf.h
+++ b/lua/luaconf.h
@@ -1,5 +1,5 @@
 /*
-** $Id: luaconf.h,v 1.254 2015/10/21 18:17:40 roberto Exp $
+** $Id: luaconf.h,v 1.255 2016/05/01 20:06:09 roberto Exp $
 ** Configuration file for Lua
 ** See Copyright Notice in lua.h
 */
@@ -612,7 +612,7 @@
 ** provide its own implementation.
 */
 #if !defined(LUA_USE_C89)
-#define lua_number2strx(L,b,sz,f,n)	l_sprintf(b,sz,f,n)
+#define lua_number2strx(L,b,sz,f,n)	((void)L, l_sprintf(b,sz,f,n))
 #endif
 
 
diff --git a/lua/lvm.c b/lua/lvm.c
index aba7ace..84ade6b 100644
--- a/lua/lvm.c
+++ b/lua/lvm.c
@@ -1,5 +1,5 @@
 /*
-** $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
 */
@@ -153,55 +153,69 @@ static int 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 */
     }
-    if (ttisfunction(tm)) {  /* metamethod is a function */
+    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)) {  /* 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));
-      /* must check the metamethod */
-      if ((tm = fasttm(L, hvalue(t)->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, hvalue(t), key), 1))) {
+    const TValue *tm;  /* '__newindex' metamethod */
+    if (slot != NULL) {  /* is 't' a table? */
+      Table *h = hvalue(t);  /* save 't' table */
+      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);
-        invalidateTMcache(hvalue(t));
-        luaC_barrierback(L, hvalue(t), val);
+        setobj2t(L, cast(TValue *, slot), val);  /* set its new value */
+        invalidateTMcache(h);
+        luaC_barrierback(L, h, val);
         return;
       }
       /* else will try the metamethod */
@@ -216,11 +230,11 @@ 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 */
   }
-  luaG_runerror(L, "settable chain too long; possible loop");
+  luaG_runerror(L, "'__newindex' chain too long; possible loop");
 }
 
 
@@ -738,18 +752,28 @@ void luaV_finishOp (lua_State *L) {
            luai_threadyield(L); }
 
 
+/* fetch an instruction and prepare its execution */
+#define vmfetch()	{ \
+  i = *(ci->u.l.savedpc++); \
+  if (L->hookmask & (LUA_MASKLINE | LUA_MASKCOUNT)) \
+    Protect(luaG_traceexec(L)); \
+  ra = RA(i); /* WARNING: any stack reallocation invalidates 'ra' */ \
+  lua_assert(base == ci->u.l.base); \
+  lua_assert(base <= L->top && L->top < L->stack + L->stacksize); \
+}
+
 #define vmdispatch(o)	switch(o)
 #define vmcase(l)	case l:
 #define vmbreak		break
 
 
 /*
-** 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' */
@@ -772,14 +796,9 @@ void luaV_execute (lua_State *L) {
   base = ci->u.l.base;  /* local copy of function's base */
   /* main loop of interpreter */
   for (;;) {
-    Instruction i = *(ci->u.l.savedpc++);
+    Instruction i;
     StkId ra;
-    if (L->hookmask & (LUA_MASKLINE | LUA_MASKCOUNT))
-      Protect(luaG_traceexec(L));
-    /* WARNING: several calls may realloc the stack and invalidate 'ra' */
-    ra = RA(i);
-    lua_assert(base == ci->u.l.base);
-    lua_assert(base <= L->top && L->top < L->stack + L->stacksize);
+    vmfetch();
     vmdispatch (GET_OPCODE(i)) {
       vmcase(OP_MOVE) {
         setobjs2s(L, ra, RB(i));
diff --git a/lua/lvm.h b/lua/lvm.h
index fd0e748..bcf52d2 100644
--- a/lua/lvm.h
+++ b/lua/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_gettable(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_gettable(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); }
 
 
 /*
@@ -100,9 +99,9 @@ LUAI_FUNC int luaV_lessequal (lua_State *L, const TValue *l, const TValue *r);
 LUAI_FUNC int luaV_tonumber_ (const TValue *obj, lua_Number *n);
 LUAI_FUNC int luaV_tointeger (const TValue *obj, lua_Integer *p, int mode);
 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);
 LUAI_FUNC void luaV_execute (lua_State *L);
 LUAI_FUNC void luaV_concat (lua_State *L, int total);