Update lua plugin to 5.2.3

Prior to this patch the Lua plugin used version 5.1.4. This change
reduces the number of modifications in the Lua source using some new
defines and because the upstream source is now more flexible.

Unless otherwise stated, l*.[ch] files are taken unmodified from the
upstream lua-5.2.3.

fscanf.c:
file descriptors in rockbox are just ints, they are hidden behind a
void* now so liolib requires less modifications. fscanf is updated to
use void* too.

getc.c: this is a new file required for getc implementation in lauxlib.c

lauxlib.c: LoadF replaced FILE* with int, the rockbox file
descriptor int are cast to FILE* (actually void* due to typedef).
getc uses the PREFIX version. stdin is not used, as per 5.1.4.

lbaselib.c: now uses strspn in the number parsing. print uses DEBUGF now
rather than being commented out.

lbitlib.c: use the built-in version from 5.2.3 rather than Reuben
Thomas's external library. Backwards compatible and adds some new bit
operations.

ldo.c: the LUAI_THROW/TRY defines are now in the core lua code, so have
been removed from rockconf.h

liolib.c: here the implementation has changed to use the LStream from
the original source, and cast the FILE* pointers to int. This has
reduced the number of modifications from the upstream version.

llex.c: the only change from upstream is to remove the locale include.

lmathlib.c: updated from the 5.2.3 version and re-applied the changes
that were made vs 5.1.4 for random numbers and to remove unsupported
float functions.

loadlib.c: upstream version, with the 5.1.4 changes for missing
functions.

lobject.c: upstream version, with ctype.h added and sprintf changed to
snprintf.

loslib.c: upstream version with locale.h removed and 5.1.4 changes for
unsupportable functions.

lstrlib.c: sprintf changed to snprintf.

ltable.c: upstream with the hashnum function from 5.1.4 to avoid frexp
in luai_hashnum.

luaconf.h: updated to 5.2.3 version, restored relevant parts from the
original 5.1.4 configuration. The COMPAT defines that are no longer
available are not included.

lundump.c: VERSION macro conflicts with the core Rockbox equivalent.

rocklib.c: luaL_reg is no longer available, replaced by luaL_Reg
equivalent. Moved checkboolean/optboolean functions to this file and out
of core lua files. luaL_getn is no longer available, replaced by
luaL_rawlen. luaL_register is deprecated, use the newlib/setfuncs
replacements. rli_init has to be called before setting up the newlib to
avoid overwriting the rb table.

rocklib_aux.pl: use rli_checkboolean from rocklib.c.

rocklua.c: new default bits library used, update the library loading
code with idiomatic 5.2 code.

strcspn.c: no longer needed, but strspn.c is required for strspn in
lbaselib.c

Change-Id: I0c7945c755f79083afe98ec117e1e8cf13de2651
Reviewed-on: http://gerrit.rockbox.org/774
Tested: Richard Quirk <richard.quirk@gmail.com>
Reviewed-by: Marcin Bukat <marcin.bukat@gmail.com>

1 files changed, 218 insertions, 150 deletions

diff --git a/apps/plugins/lua/llex.c b/apps/plugins/lua/llex.c
index 85ac516be3..8d410f620d 100644
--- a/apps/plugins/lua/llex.c
+++ b/apps/plugins/lua/llex.c
@@ -1,12 +1,10 @@
 /*
-** $Id: llex.c,v 2.20.1.1 2007/12/27 13:02:25 roberto Exp $
+** $Id: llex.c,v 2.63.1.2 2013/08/30 15:49:41 roberto Exp $
 ** Lexical Analyzer
 ** See Copyright Notice in lua.h
 */
 
 
-#include <ctype.h>
-/* #include <locale.h> */
 #include <string.h>
 
 #define llex_c
@@ -14,6 +12,7 @@
 
 #include "lua.h"
 
+#include "lctype.h"
 #include "ldo.h"
 #include "llex.h"
 #include "lobject.h"
@@ -29,35 +28,36 @@
 
 
 
-
 #define currIsNewline(ls)       (ls->current == '\n' || ls->current == '\r')
 
 
 /* ORDER RESERVED */
-const char *const luaX_tokens [] = {
+static const char *const luaX_tokens [] = {
     "and", "break", "do", "else", "elseif",
-    "end", "false", "for", "function", "if",
+    "end", "false", "for", "function", "goto", "if",
     "in", "local", "nil", "not", "or", "repeat",
     "return", "then", "true", "until", "while",
-    "..", "...", "==", ">=", "<=", "~=",
-    "<number>", "<name>", "<string>", "<eof>",
-    NULL
+    "..", "...", "==", ">=", "<=", "~=", "::", "<eof>",
+    "<number>", "<name>", "<string>"
 };
 
 
 #define save_and_next(ls) (save(ls, ls->current), next(ls))
 
 
+static l_noret lexerror (LexState *ls, const char *msg, int token);
+
+
 static void save (LexState *ls, int c) {
   Mbuffer *b = ls->buff;
-  if (b->n + 1 > b->buffsize) {
+  if (luaZ_bufflen(b) + 1 > luaZ_sizebuffer(b)) {
     size_t newsize;
-    if (b->buffsize >= MAX_SIZET/2)
-      luaX_lexerror(ls, "lexical element too long", 0);
-    newsize = b->buffsize * 2;
+    if (luaZ_sizebuffer(b) >= MAX_SIZET/2)
+      lexerror(ls, "lexical element too long", 0);
+    newsize = luaZ_sizebuffer(b) * 2;
     luaZ_resizebuffer(ls->L, b, newsize);
   }
-  b->buffer[b->n++] = cast(char, c);
+  b->buffer[luaZ_bufflen(b)++] = cast(char, c);
 }
 
 
@@ -66,23 +66,24 @@ void luaX_init (lua_State *L) {
   for (i=0; i<NUM_RESERVED; i++) {
     TString *ts = luaS_new(L, luaX_tokens[i]);
     luaS_fix(ts);  /* reserved words are never collected */
-    lua_assert(strlen(luaX_tokens[i])+1 <= TOKEN_LEN);
-    ts->tsv.reserved = cast_byte(i+1);  /* reserved word */
+    ts->tsv.extra = cast_byte(i+1);  /* reserved word */
   }
 }
 
 
-#define MAXSRC          80
-
-
 const char *luaX_token2str (LexState *ls, int token) {
-  if (token < FIRST_RESERVED) {
+  if (token < FIRST_RESERVED) {  /* single-byte symbols? */
     lua_assert(token == cast(unsigned char, token));
-    return (iscntrl(token)) ? luaO_pushfstring(ls->L, "char(%d)", token) :
-                              luaO_pushfstring(ls->L, "%c", token);
+    return (lisprint(token)) ? luaO_pushfstring(ls->L, LUA_QL("%c"), token) :
+                              luaO_pushfstring(ls->L, "char(%d)", token);
+  }
+  else {
+    const char *s = luaX_tokens[token - FIRST_RESERVED];
+    if (token < TK_EOS)  /* fixed format (symbols and reserved words)? */
+      return luaO_pushfstring(ls->L, LUA_QS, s);
+    else  /* names, strings, and numerals */
+      return s;
   }
-  else
-    return luaX_tokens[token-FIRST_RESERVED];
 }
 
 
@@ -92,38 +93,57 @@ static const char *txtToken (LexState *ls, int token) {
     case TK_STRING:
     case TK_NUMBER:
       save(ls, '\0');
-      return luaZ_buffer(ls->buff);
+      return luaO_pushfstring(ls->L, LUA_QS, luaZ_buffer(ls->buff));
     default:
       return luaX_token2str(ls, token);
   }
 }
 
 
-void luaX_lexerror (LexState *ls, const char *msg, int token) {
-  char buff[MAXSRC];
-  luaO_chunkid(buff, getstr(ls->source), MAXSRC);
+static l_noret lexerror (LexState *ls, const char *msg, int token) {
+  char buff[LUA_IDSIZE];
+  luaO_chunkid(buff, getstr(ls->source), LUA_IDSIZE);
   msg = luaO_pushfstring(ls->L, "%s:%d: %s", buff, ls->linenumber, msg);
   if (token)
-    luaO_pushfstring(ls->L, "%s near " LUA_QS, msg, txtToken(ls, token));
+    luaO_pushfstring(ls->L, "%s near %s", msg, txtToken(ls, token));
   luaD_throw(ls->L, LUA_ERRSYNTAX);
 }
 
 
-void luaX_syntaxerror (LexState *ls, const char *msg) {
-  luaX_lexerror(ls, msg, ls->t.token);
+l_noret luaX_syntaxerror (LexState *ls, const char *msg) {
+  lexerror(ls, msg, ls->t.token);
 }
 
 
+/*
+** creates a new string and anchors it in function's table so that
+** it will not be collected until the end of the function's compilation
+** (by that time it should be anchored in function's prototype)
+*/
 TString *luaX_newstring (LexState *ls, const char *str, size_t l) {
   lua_State *L = ls->L;
-  TString *ts = luaS_newlstr(L, str, l);
-  TValue *o = luaH_setstr(L, ls->fs->h, ts);  /* entry for `str' */
-  if (ttisnil(o))
-    setbvalue(o, 1);  /* make sure `str' will not be collected */
+  TValue *o;  /* entry for `str' */
+  TString *ts = luaS_newlstr(L, str, l);  /* create new string */
+  setsvalue2s(L, L->top++, ts);  /* temporarily anchor it in stack */
+  o = luaH_set(L, ls->fs->h, L->top - 1);
+  if (ttisnil(o)) {  /* not in use yet? (see 'addK') */
+    /* boolean value does not need GC barrier;
+       table has no metatable, so it does not need to invalidate cache */
+    setbvalue(o, 1);  /* t[string] = true */
+    luaC_checkGC(L);
+  }
+  else {  /* string already present */
+    ts = rawtsvalue(keyfromval(o));  /* re-use value previously stored */
+  }
+  L->top--;  /* remove string from stack */
   return ts;
 }
 
 
+/*
+** increment line number and skips newline sequence (any of
+** \n, \r, \n\r, or \r\n)
+*/
 static void inclinenumber (LexState *ls) {
   int old = ls->current;
   lua_assert(currIsNewline(ls));
@@ -135,17 +155,20 @@ static void inclinenumber (LexState *ls) {
 }
 
 
-void luaX_setinput (lua_State *L, LexState *ls, ZIO *z, TString *source) {
+void luaX_setinput (lua_State *L, LexState *ls, ZIO *z, TString *source,
+                    int firstchar) {
   ls->decpoint = '.';
   ls->L = L;
+  ls->current = firstchar;
   ls->lookahead.token = TK_EOS;  /* no look-ahead token */
   ls->z = z;
   ls->fs = NULL;
   ls->linenumber = 1;
   ls->lastline = 1;
   ls->source = source;
+  ls->envn = luaS_new(L, LUA_ENV);  /* create env name */
+  luaS_fix(ls->envn);  /* never collect this name */
   luaZ_resizebuffer(ls->L, ls->buff, LUA_MINBUFFER);  /* initialize buffer */
-  next(ls);  /* read first char */
 }
 
 
@@ -159,13 +182,16 @@ void luaX_setinput (lua_State *L, LexState *ls, ZIO *z, TString *source) {
 
 
 static int check_next (LexState *ls, const char *set) {
-  if (!strchr(set, ls->current))
+  if (ls->current == '\0' || !strchr(set, ls->current))
     return 0;
   save_and_next(ls);
   return 1;
 }
 
 
+/*
+** change all characters 'from' in buffer to 'to'
+*/
 static void buffreplace (LexState *ls, char from, char to) {
   size_t n = luaZ_bufflen(ls->buff);
   char *p = luaZ_buffer(ls->buff);
@@ -174,37 +200,59 @@ static void buffreplace (LexState *ls, char from, char to) {
 }
 
 
+#if !defined(getlocaledecpoint)
+#define getlocaledecpoint()     (localeconv()->decimal_point[0])
+#endif
+
+
+#define buff2d(b,e)     luaO_str2d(luaZ_buffer(b), luaZ_bufflen(b) - 1, e)
+
+/*
+** 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, SemInfo *seminfo) {
-  /* format error: try to update decimal point separator */
-  /* struct lconv *cv = localeconv(); */
   char old = ls->decpoint;
-  ls->decpoint = '.'; /* (cv ? cv->decimal_point[0] : '.'); */
-  buffreplace(ls, old, ls->decpoint);  /* try updated decimal separator */
-  if (!luaO_str2d(luaZ_buffer(ls->buff), &seminfo->r)) {
+  ls->decpoint = getlocaledecpoint();
+  buffreplace(ls, old, ls->decpoint);  /* try new decimal separator */
+  if (!buff2d(ls->buff, &seminfo->r)) {
     /* format error with correct decimal point: no more options */
     buffreplace(ls, ls->decpoint, '.');  /* undo change (for error message) */
-    luaX_lexerror(ls, "malformed number", TK_NUMBER);
+    lexerror(ls, "malformed number", TK_NUMBER);
   }
 }
 
 
 /* LUA_NUMBER */
+/*
+** this function is quite liberal in what it accepts, as 'luaO_str2d'
+** will reject ill-formed numerals.
+*/
 static void read_numeral (LexState *ls, SemInfo *seminfo) {
-  lua_assert(isdigit(ls->current));
-  do {
-    save_and_next(ls);
-  } while (isdigit(ls->current) || ls->current == '.');
-  if (check_next(ls, "Ee"))  /* `E'? */
-    check_next(ls, "+-");  /* optional exponent sign */
-  while (isalnum(ls->current) || ls->current == '_')
-    save_and_next(ls);
+  const char *expo = "Ee";
+  int first = ls->current;
+  lua_assert(lisdigit(ls->current));
+  save_and_next(ls);
+  if (first == '0' && check_next(ls, "Xx"))  /* hexadecimal? */
+    expo = "Pp";
+  for (;;) {
+    if (check_next(ls, expo))  /* exponent part? */
+      check_next(ls, "+-");  /* optional exponent sign */
+    if (lisxdigit(ls->current) || ls->current == '.')
+      save_and_next(ls);
+    else  break;
+  }
   save(ls, '\0');
   buffreplace(ls, '.', ls->decpoint);  /* follow locale for decimal point */
-  if (!luaO_str2d(luaZ_buffer(ls->buff), &seminfo->r))  /* format error? */
+  if (!buff2d(ls->buff, &seminfo->r))  /* format error? */
     trydecpoint(ls, seminfo); /* try to update decimal point separator */
 }
 
 
+/*
+** skip a sequence '[=*[' or ']=*]' and return its number of '='s or
+** -1 if sequence is malformed
+*/
 static int skip_sep (LexState *ls) {
   int count = 0;
   int s = ls->current;
@@ -219,43 +267,23 @@ static int skip_sep (LexState *ls) {
 
 
 static void read_long_string (LexState *ls, SemInfo *seminfo, int sep) {
-  int cont = 0;
-  (void)(cont);  /* avoid warnings when `cont' is not used */
   save_and_next(ls);  /* skip 2nd `[' */
   if (currIsNewline(ls))  /* string starts with a newline? */
     inclinenumber(ls);  /* skip it */
   for (;;) {
     switch (ls->current) {
       case EOZ:
-        luaX_lexerror(ls, (seminfo) ? "unfinished long string" :
-                                   "unfinished long comment", TK_EOS);
+        lexerror(ls, (seminfo) ? "unfinished long string" :
+                                 "unfinished long comment", TK_EOS);
         break;  /* to avoid warnings */
-#if defined(LUA_COMPAT_LSTR)
-      case '[': {
-        if (skip_sep(ls) == sep) {
-          save_and_next(ls);  /* skip 2nd `[' */
-          cont++;
-#if LUA_COMPAT_LSTR == 1
-          if (sep == 0)
-            luaX_lexerror(ls, "nesting of [[...]] is deprecated", '[');
-#endif
-        }
-        break;
-      }
-#endif
       case ']': {
         if (skip_sep(ls) == sep) {
           save_and_next(ls);  /* skip 2nd `]' */
-#if defined(LUA_COMPAT_LSTR) && LUA_COMPAT_LSTR == 2
-          cont--;
-          if (sep == 0 && cont >= 0) break;
-#endif
           goto endloop;
         }
         break;
       }
-      case '\n':
-      case '\r': {
+      case '\n': case '\r': {
         save(ls, '\n');
         inclinenumber(ls);
         if (!seminfo) luaZ_resetbuffer(ls->buff);  /* avoid wasting space */
@@ -273,51 +301,91 @@ static void read_long_string (LexState *ls, SemInfo *seminfo, int sep) {
 }
 
 
+static void escerror (LexState *ls, int *c, int n, const char *msg) {
+  int i;
+  luaZ_resetbuffer(ls->buff);  /* prepare error message */
+  save(ls, '\\');
+  for (i = 0; i < n && c[i] != EOZ; i++)
+    save(ls, c[i]);
+  lexerror(ls, msg, TK_STRING);
+}
+
+
+static int readhexaesc (LexState *ls) {
+  int c[3], i;  /* keep input for error message */
+  int r = 0;  /* result accumulator */
+  c[0] = 'x';  /* for error message */
+  for (i = 1; i < 3; i++) {  /* read two hexadecimal digits */
+    c[i] = next(ls);
+    if (!lisxdigit(c[i]))
+      escerror(ls, c, i + 1, "hexadecimal digit expected");
+    r = (r << 4) + luaO_hexavalue(c[i]);
+  }
+  return r;
+}
+
+
+static int readdecesc (LexState *ls) {
+  int c[3], i;
+  int r = 0;  /* result accumulator */
+  for (i = 0; i < 3 && lisdigit(ls->current); i++) {  /* read up to 3 digits */
+    c[i] = ls->current;
+    r = 10*r + c[i] - '0';
+    next(ls);
+  }
+  if (r > UCHAR_MAX)
+    escerror(ls, c, i, "decimal escape too large");
+  return r;
+}
+
+
 static void read_string (LexState *ls, int del, SemInfo *seminfo) {
-  save_and_next(ls);
+  save_and_next(ls);  /* keep delimiter (for error messages) */
   while (ls->current != del) {
     switch (ls->current) {
       case EOZ:
-        luaX_lexerror(ls, "unfinished string", TK_EOS);
-        continue;  /* to avoid warnings */
+        lexerror(ls, "unfinished string", TK_EOS);
+        break;  /* to avoid warnings */
       case '\n':
       case '\r':
-        luaX_lexerror(ls, "unfinished string", TK_STRING);
-        continue;  /* to avoid warnings */
-      case '\\': {
-        int c;
+        lexerror(ls, "unfinished string", TK_STRING);
+        break;  /* to avoid warnings */
+      case '\\': {  /* escape sequences */
+        int c;  /* final character to be saved */
         next(ls);  /* do not save the `\' */
         switch (ls->current) {
-          case 'a': c = '\a'; break;
-          case 'b': c = '\b'; break;
-          case 'f': c = '\f'; break;
-          case 'n': c = '\n'; break;
-          case 'r': c = '\r'; break;
-          case 't': c = '\t'; break;
-          case 'v': c = '\v'; break;
-          case '\n':  /* go through */
-          case '\r': save(ls, '\n'); inclinenumber(ls); continue;
-          case EOZ: continue;  /* will raise an error next loop */
-          default: {
-            if (!isdigit(ls->current))
-              save_and_next(ls);  /* handles \\, \", \', and \? */
-            else {  /* \xxx */
-              int i = 0;
-              c = 0;
-              do {
-                c = 10*c + (ls->current-'0');
-                next(ls);
-              } while (++i<3 && isdigit(ls->current));
-              if (c > UCHAR_MAX)
-                luaX_lexerror(ls, "escape sequence too large", TK_STRING);
-              save(ls, c);
+          case 'a': c = '\a'; goto read_save;
+          case 'b': c = '\b'; goto read_save;
+          case 'f': c = '\f'; goto read_save;
+          case 'n': c = '\n'; goto read_save;
+          case 'r': c = '\r'; goto read_save;
+          case 't': c = '\t'; goto read_save;
+          case 'v': c = '\v'; goto read_save;
+          case 'x': c = readhexaesc(ls); goto read_save;
+          case '\n': case '\r':
+            inclinenumber(ls); c = '\n'; goto only_save;
+          case '\\': case '\"': case '\'':
+            c = ls->current; goto read_save;
+          case EOZ: goto no_save;  /* will raise an error next loop */
+          case 'z': {  /* zap following span of spaces */
+            next(ls);  /* skip the 'z' */
+            while (lisspace(ls->current)) {
+              if (currIsNewline(ls)) inclinenumber(ls);
+              else next(ls);
             }
-            continue;
+            goto no_save;
+          }
+          default: {
+            if (!lisdigit(ls->current))
+              escerror(ls, &ls->current, 1, "invalid escape sequence");
+            /* digital escape \ddd */
+            c = readdecesc(ls);
+            goto only_save;
           }
         }
-        save(ls, c);
-        next(ls);
-        continue;
+       read_save: next(ls);  /* read next character */
+       only_save: save(ls, c);  /* save 'c' */
+       no_save: break;
       }
       default:
         save_and_next(ls);
@@ -333,38 +401,41 @@ static int llex (LexState *ls, SemInfo *seminfo) {
   luaZ_resetbuffer(ls->buff);
   for (;;) {
     switch (ls->current) {
-      case '\n':
-      case '\r': {
+      case '\n': case '\r': {  /* line breaks */
         inclinenumber(ls);
-        continue;
+        break;
       }
-      case '-': {
+      case ' ': case '\f': case '\t': case '\v': {  /* spaces */
+        next(ls);
+        break;
+      }
+      case '-': {  /* '-' or '--' (comment) */
         next(ls);
         if (ls->current != '-') return '-';
         /* else is a comment */
         next(ls);
-        if (ls->current == '[') {
+        if (ls->current == '[') {  /* long comment? */
           int sep = skip_sep(ls);
           luaZ_resetbuffer(ls->buff);  /* `skip_sep' may dirty the buffer */
           if (sep >= 0) {
-            read_long_string(ls, NULL, sep);  /* long comment */
-            luaZ_resetbuffer(ls->buff);
-            continue;
+            read_long_string(ls, NULL, sep);  /* skip long comment */
+            luaZ_resetbuffer(ls->buff);  /* previous call may dirty the buff. */
+            break;
           }
         }
         /* else short comment */
         while (!currIsNewline(ls) && ls->current != EOZ)
-          next(ls);
-        continue;
+          next(ls);  /* skip until end of line (or end of file) */
+        break;
       }
-      case '[': {
+      case '[': {  /* long string or simply '[' */
         int sep = skip_sep(ls);
         if (sep >= 0) {
           read_long_string(ls, seminfo, sep);
           return TK_STRING;
         }
         else if (sep == -1) return '[';
-        else luaX_lexerror(ls, "invalid long string delimiter", TK_STRING);
+        else lexerror(ls, "invalid long string delimiter", TK_STRING);
       }
       case '=': {
         next(ls);
@@ -386,56 +457,52 @@ static int llex (LexState *ls, SemInfo *seminfo) {
         if (ls->current != '=') return '~';
         else { next(ls); return TK_NE; }
       }
-      case '"':
-      case '\'': {
+      case ':': {
+        next(ls);
+        if (ls->current != ':') return ':';
+        else { next(ls); return TK_DBCOLON; }
+      }
+      case '"': case '\'': {  /* short literal strings */
         read_string(ls, ls->current, seminfo);
         return TK_STRING;
       }
-      case '.': {
+      case '.': {  /* '.', '..', '...', or number */
         save_and_next(ls);
         if (check_next(ls, ".")) {
           if (check_next(ls, "."))
-            return TK_DOTS;   /* ... */
-          else return TK_CONCAT;   /* .. */
-        }
-        else if (!isdigit(ls->current)) return '.';
-        else {
-          read_numeral(ls, seminfo);
-          return TK_NUMBER;
+            return TK_DOTS;   /* '...' */
+          else return TK_CONCAT;   /* '..' */
         }
+        else if (!lisdigit(ls->current)) return '.';
+        /* else go through */
+      }
+      case '0': case '1': case '2': case '3': case '4':
+      case '5': case '6': case '7': case '8': case '9': {
+        read_numeral(ls, seminfo);
+        return TK_NUMBER;
       }
       case EOZ: {
         return TK_EOS;
       }
       default: {
-        if (isspace(ls->current)) {
-          lua_assert(!currIsNewline(ls));
-          next(ls);
-          continue;
-        }
-        else if (isdigit(ls->current)) {
-          read_numeral(ls, seminfo);
-          return TK_NUMBER;
-        }
-        else if (isalpha(ls->current) || ls->current == '_') {
-          /* identifier or reserved word */
+        if (lislalpha(ls->current)) {  /* identifier or reserved word? */
           TString *ts;
           do {
             save_and_next(ls);
-          } while (isalnum(ls->current) || ls->current == '_');
+          } while (lislalnum(ls->current));
           ts = luaX_newstring(ls, luaZ_buffer(ls->buff),
                                   luaZ_bufflen(ls->buff));
-          if (ts->tsv.reserved > 0)  /* reserved word? */
-            return ts->tsv.reserved - 1 + FIRST_RESERVED;
+          seminfo->ts = ts;
+          if (isreserved(ts))  /* reserved word? */
+            return ts->tsv.extra - 1 + FIRST_RESERVED;
           else {
-            seminfo->ts = ts;
             return TK_NAME;
           }
         }
-        else {
+        else {  /* single-char tokens (+ - / ...) */
           int c = ls->current;
           next(ls);
-          return c;  /* single-char tokens (+ - / ...) */
+          return c;
         }
       }
     }
@@ -454,8 +521,9 @@ void luaX_next (LexState *ls) {
 }
 
 
-void luaX_lookahead (LexState *ls) {
+int luaX_lookahead (LexState *ls) {
   lua_assert(ls->lookahead.token == TK_EOS);
   ls->lookahead.token = llex(ls, &ls->lookahead.seminfo);
+  return ls->lookahead.token;
 }