new API function `lua_type' + new type lua_Type

15 files changed, 125 insertions, 102 deletions

diff --git a/lapi.c b/lapi.c
index f2cd0b0d..48488d3a 100644
--- a/lapi.c
+++ b/lapi.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lapi.c,v 1.101 2000/09/29 12:42:13 roberto Exp roberto $
+** $Id: lapi.c,v 1.102 2000/10/02 14:47:43 roberto Exp roberto $
 ** Lua API
 ** See Copyright Notice in lua.h
 */
@@ -116,8 +116,16 @@ void lua_pushvalue (lua_State *L, int index) {
   return ((test) ? (value) : (default)); }
 
 
-const char *lua_type (lua_State *L, int index) {
-  btest(L, index, luaO_typename(o), "NO VALUE");
+lua_Type lua_type (lua_State *L, int index) {
+  btest(L, index, luaO_type(o), LUA_NOVALUE);
+}
+
+const char *lua_typename (lua_State *L, lua_Type t) {
+  static const char *const names[] = {
+    "NO VALUE", "userdata", "number", "string", "table", "function", "nil"
+  };
+  UNUSED(L);
+  return names[(int)t];
 }
 
 int lua_iscfunction (lua_State *L, int index) {
@@ -128,6 +136,11 @@ int lua_isnumber (lua_State *L, int index) {
   btest(L, index, (tonumber(Index(L, index)) == 0), 0);
 }
 
+int lua_isstring (lua_State *L, int index) {
+  lua_Type t = lua_type(L, index);
+  return (t == LUA_TSTRING || t == LUA_TNUMBER);
+}
+
 int lua_tag (lua_State *L, int index) {
   btest(L, index, 
    ((ttype(o) == TAG_USERDATA) ? tsvalue(o)->u.d.tag :
@@ -411,7 +424,7 @@ void lua_settag (lua_State *L, int tag) {
       break;
     default:
       luaO_verror(L, "cannot change the tag of a %.20s",
-                  luaO_typename(L->top-1));
+                  luaO_typename(L, L->top-1));
   }
   L->top--;
 }
diff --git a/lauxlib.c b/lauxlib.c
index d1fdb31d..d6398795 100644
--- a/lauxlib.c
+++ b/lauxlib.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lauxlib.c,v 1.36 2000/09/12 13:48:22 roberto Exp roberto $
+** $Id: lauxlib.c,v 1.37 2000/09/29 12:40:56 roberto Exp roberto $
 ** Auxiliary functions for building Lua libraries
 ** See Copyright Notice in lua.h
 */
@@ -40,11 +40,11 @@ void luaL_argerror (lua_State *L, int narg, const char *extramsg) {
 }
 
 
-static void type_error (lua_State *L, int narg, const char *type_name) {
+static void type_error (lua_State *L, int narg, lua_Type t) {
   char buff[100];
-  const char *rt = lua_type(L, narg);
+  const char *rt = lua_typename(L, lua_type(L, narg));
   if (*rt == 'N') rt = "no value";
-  sprintf(buff, "%.10s expected, got %.10s", type_name, rt);
+  sprintf(buff, "%.10s expected, got %.10s", lua_typename(L, t), rt);
   luaL_argerror(L, narg, buff);
 }
 
@@ -55,20 +55,21 @@ void luaL_checkstack (lua_State *L, int space, const char *mes) {
 }
 
 
-/*
-** use the 3rd letter of type names for testing:
-** nuMber, niL, stRing, fuNction, usErdata, taBle, anY
-*/
-void luaL_checktype(lua_State *L, int narg, const char *tname) {
-  const char *rt = lua_type(L, narg);
-  if (!(*rt != 'N' && (tname[2] == 'y' || tname[2] == rt[2])))
-    type_error(L, narg, tname);
+void luaL_checktype(lua_State *L, int narg, lua_Type t) {
+  if (lua_type(L, narg) != t)
+    type_error(L, narg, t);
+}
+
+
+void luaL_checkany (lua_State *L, int narg) {
+  if (lua_type(L, narg) == LUA_NOVALUE)
+    luaL_argerror(L, narg, "value expected");
 }
 
 
 const char *luaL_check_lstr (lua_State *L, int narg, size_t *len) {
   const char *s = lua_tostring(L, narg);
-  if (!s) type_error(L, narg, "string");
+  if (!s) type_error(L, narg, LUA_TSTRING);
   if (len) *len = lua_strlen(L, narg);
   return s;
 }
@@ -88,7 +89,7 @@ const char *luaL_opt_lstr (lua_State *L, int narg, const char *def,
 double luaL_check_number (lua_State *L, int narg) {
   double d = lua_tonumber(L, narg);
   if (d == 0 && !lua_isnumber(L, narg))  /* avoid extra test when d is not 0 */
-    type_error(L, narg, "number");
+    type_error(L, narg, LUA_TNUMBER);
   return d;
 }
 
diff --git a/lauxlib.h b/lauxlib.h
index 95d61006..54949d86 100644
--- a/lauxlib.h
+++ b/lauxlib.h
@@ -1,5 +1,5 @@
 /*
-** $Id: lauxlib.h,v 1.24 2000/09/11 20:29:27 roberto Exp roberto $
+** $Id: lauxlib.h,v 1.25 2000/09/12 13:48:22 roberto Exp roberto $
 ** Auxiliary functions for building Lua libraries
 ** See Copyright Notice in lua.h
 */
@@ -30,7 +30,8 @@ double luaL_check_number (lua_State *L, int numArg);
 double luaL_opt_number (lua_State *L, int numArg, double def);
 
 void luaL_checkstack (lua_State *L, int space, const char *msg);
-void luaL_checktype (lua_State *L, int narg, const char *tname);
+void luaL_checktype (lua_State *L, int narg, lua_Type t);
+void luaL_checkany (lua_State *L, int narg);
 
 void luaL_verror (lua_State *L, const char *fmt, ...);
 int luaL_findstring (const char *name, const char *const list[]);
diff --git a/lbaselib.c b/lbaselib.c
index 1a3031ac..9c1e6f0b 100644
--- a/lbaselib.c
+++ b/lbaselib.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lbaselib.c,v 1.6 2000/09/20 12:54:17 roberto Exp roberto $
+** $Id: lbaselib.c,v 1.7 2000/10/02 14:47:43 roberto Exp roberto $
 ** Basic library
 ** See Copyright Notice in lua.h
 */
@@ -34,7 +34,7 @@ static int luaB__ALERT (lua_State *L) {
 ** The library `liolib' redefines _ERRORMESSAGE for better error information.
 */
 static int luaB__ERRORMESSAGE (lua_State *L) {
-  luaL_checktype(L, 1, "string");
+  luaL_checktype(L, 1, LUA_TSTRING);
   lua_getglobal(L, LUA_ALERT);
   if (lua_isfunction(L, -1)) {  /* avoid error loop if _ALERT is not defined */
     lua_Debug ar;
@@ -87,7 +87,7 @@ static int luaB_print (lua_State *L) {
 static int luaB_tonumber (lua_State *L) {
   int base = luaL_opt_int(L, 2, 10);
   if (base == 10) {  /* standard conversion */
-    luaL_checktype(L, 1, "any");
+    luaL_checkany(L, 1);
     if (lua_isnumber(L, 1)) {
       lua_pushnumber(L, lua_tonumber(L, 1));
       return 1;
@@ -118,7 +118,7 @@ static int luaB_error (lua_State *L) {
 }
 
 static int luaB_setglobal (lua_State *L) {
-  luaL_checktype(L, 2, "any");
+  luaL_checkany(L, 2);
   lua_setglobal(L, luaL_check_string(L, 1));
   return 0;
 }
@@ -129,13 +129,13 @@ static int luaB_getglobal (lua_State *L) {
 }
 
 static int luaB_tag (lua_State *L) {
-  luaL_checktype(L, 1, "any");
+  luaL_checkany(L, 1);
   lua_pushnumber(L, lua_tag(L, 1));
   return 1;
 }
 
 static int luaB_settag (lua_State *L) {
-  luaL_checktype(L, 1, "table");
+  luaL_checktype(L, 1, LUA_TTABLE);
   lua_pushvalue(L, 1);  /* push table */
   lua_settag(L, luaL_check_int(L, 2));
   lua_pop(L, 1);  /* remove second argument */
@@ -156,7 +156,7 @@ static int luaB_copytagmethods (lua_State *L) {
 static int luaB_globals (lua_State *L) {
   lua_getglobals(L);  /* value to be returned */
   if (!lua_isnull(L, 1)) {
-    luaL_checktype(L, 1, "table");
+    luaL_checktype(L, 1, LUA_TTABLE);
     lua_pushvalue(L, 1);  /* new table of globals */
     lua_setglobals(L);
   }
@@ -164,16 +164,16 @@ static int luaB_globals (lua_State *L) {
 }
 
 static int luaB_rawget (lua_State *L) {
-  luaL_checktype(L, 1, "table");
-  luaL_checktype(L, 2, "any");
+  luaL_checktype(L, 1, LUA_TTABLE);
+  luaL_checkany(L, 2);
   lua_rawget(L, -2);
   return 1;
 }
 
 static int luaB_rawset (lua_State *L) {
-  luaL_checktype(L, 1, "table");
-  luaL_checktype(L, 2, "any");
-  luaL_checktype(L, 3, "any");
+  luaL_checktype(L, 1, LUA_TTABLE);
+  luaL_checkany(L, 2);
+  luaL_checkany(L, 3);
   lua_rawset(L, -3);
   return 1;
 }
@@ -209,14 +209,14 @@ static int luaB_collectgarbage (lua_State *L) {
 
 
 static int luaB_type (lua_State *L) {
-  luaL_checktype(L, 1, "any");
-  lua_pushstring(L, lua_type(L, 1));
+  luaL_checkany(L, 1);
+  lua_pushstring(L, lua_typename(L, lua_type(L, 1)));
   return 1;
 }
 
 
 static int luaB_next (lua_State *L) {
-  luaL_checktype(L, 1, "table");
+  luaL_checktype(L, 1, LUA_TTABLE);
   lua_settop(L, 2);  /* create a 2nd argument if there isn't one */
   if (lua_next(L, 1))
     return 2;
@@ -269,7 +269,7 @@ static int luaB_call (lua_State *L) {
   int err = 0;  /* index of old error method */
   int i, status;
   int n;
-  luaL_checktype(L, 2, "table");
+  luaL_checktype(L, 2, LUA_TTABLE);
   n = lua_getn(L, 2);
   if (!lua_isnull(L, 4)) {  /* set new error method */
     lua_getglobal(L, LUA_ERRORMESSAGE);
@@ -303,26 +303,26 @@ static int luaB_call (lua_State *L) {
 
 static int luaB_tostring (lua_State *L) {
   char buff[64];
-  switch (lua_type(L, 1)[2]) {
-    case 'm':  /* nuMber */
+  switch (lua_type(L, 1)) {
+    case LUA_TNUMBER:
       lua_pushstring(L, lua_tostring(L, 1));
       return 1;
-    case 'r':  /* stRing */
+    case LUA_TSTRING:
       lua_pushvalue(L, 1);
       return 1;
-    case 'b':  /* taBle */
+    case LUA_TTABLE:
       sprintf(buff, "table: %p", lua_topointer(L, 1));
       break;
-    case 'n':  /* fuNction */
+    case LUA_TFUNCTION:
       sprintf(buff, "function: %p", lua_topointer(L, 1));
       break;
-    case 'e':  /* usErdata */
+    case LUA_TUSERDATA:
       sprintf(buff, "userdata(%d): %p", lua_tag(L, 1), lua_touserdata(L, 1));
       break;
-    case 'l':  /* niL */
+    case LUA_TNIL:
       lua_pushstring(L, "nil");
       return 1;
-    default:
+    case LUA_NOVALUE:
       luaL_argerror(L, 1, "value expected");
   }
   lua_pushstring(L, buff);
@@ -332,8 +332,8 @@ static int luaB_tostring (lua_State *L) {
 
 static int luaB_foreachi (lua_State *L) {
   int n, i;
-  luaL_checktype(L, 1, "table");
-  luaL_checktype(L, 2, "function");
+  luaL_checktype(L, 1, LUA_TTABLE);
+  luaL_checktype(L, 2, LUA_TFUNCTION);
   n = lua_getn(L, 1);
   for (i=1; i<=n; i++) {
     lua_pushvalue(L, 2);  /* function */
@@ -349,8 +349,8 @@ static int luaB_foreachi (lua_State *L) {
 
 
 static int luaB_foreach (lua_State *L) {
-  luaL_checktype(L, 1, "table");
-  luaL_checktype(L, 2, "function");
+  luaL_checktype(L, 1, LUA_TTABLE);
+  luaL_checktype(L, 2, LUA_TFUNCTION);
   lua_pushnil(L);  /* first index */
   for (;;) {
     if (lua_next(L, 1) == 0)
@@ -367,7 +367,7 @@ static int luaB_foreach (lua_State *L) {
 
 
 static int luaB_assert (lua_State *L) {
-  luaL_checktype(L, 1, "any");
+  luaL_checkany(L, 1);
   if (lua_isnil(L, 1))
     luaL_verror(L, "assertion failed!  %.90s", luaL_opt_string(L, 2, ""));
   return 0;
@@ -375,7 +375,7 @@ static int luaB_assert (lua_State *L) {
 
 
 static int luaB_getn (lua_State *L) {
-  luaL_checktype(L, 1, "table");
+  luaL_checktype(L, 1, LUA_TTABLE);
   lua_pushnumber(L, lua_getn(L, 1));
   return 1;
 }
@@ -384,7 +384,7 @@ static int luaB_getn (lua_State *L) {
 static int luaB_tinsert (lua_State *L) {
   int v = lua_gettop(L);  /* last argument: to be inserted */
   int n, pos;
-  luaL_checktype(L, 1, "table");
+  luaL_checktype(L, 1, LUA_TTABLE);
   n = lua_getn(L, 1);
   if (v == 2)  /* called with only 2 arguments */
     pos = n+1;
@@ -405,7 +405,7 @@ static int luaB_tinsert (lua_State *L) {
 
 static int luaB_tremove (lua_State *L) {
   int pos, n;
-  luaL_checktype(L, 1, "table");
+  luaL_checktype(L, 1, LUA_TTABLE);
   n = lua_getn(L, 1);
   pos = luaL_opt_int(L, 2, n);
   if (n <= 0) return 0;  /* table is "empty" */
@@ -517,10 +517,10 @@ static void auxsort (lua_State *L, int l, int u) {
 
 static int luaB_sort (lua_State *L) {
   int n;
-  luaL_checktype(L, 1, "table");
+  luaL_checktype(L, 1, LUA_TTABLE);
   n = lua_getn(L, 1);
   if (!lua_isnull(L, 2))  /* is there a 2nd argument? */
-    luaL_checktype(L, 2, "function");
+    luaL_checktype(L, 2, LUA_TFUNCTION);
   lua_settop(L, 2);  /* make sure there is two arguments */
   auxsort(L, 1, n);
   return 0;
diff --git a/ldblib.c b/ldblib.c
index 761b37ea..13f2b078 100644
--- a/ldblib.c
+++ b/ldblib.c
@@ -1,5 +1,5 @@
 /*
-** $Id: ldblib.c,v 1.20 2000/09/05 19:33:32 roberto Exp roberto $
+** $Id: ldblib.c,v 1.21 2000/09/12 18:38:25 roberto Exp roberto $
 ** Interface from Lua to its debug API
 ** See Copyright Notice in lua.h
 */
@@ -103,7 +103,7 @@ static int setlocal (lua_State *L) {
   lua_Debug ar;
   if (!lua_getstack(L, luaL_check_int(L, 1), &ar))  /* level out of range? */
     luaL_argerror(L, 1, "level out of range");
-  luaL_checktype(L, 3, "any");
+  luaL_checkany(L, 3);
   lua_pushstring(L, lua_setlocal(L, &ar, luaL_check_int(L, 2)));
   return 1;
 }
diff --git a/ldebug.c b/ldebug.c
index 80eff4e3..cec9f191 100644
--- a/ldebug.c
+++ b/ldebug.c
@@ -1,5 +1,5 @@
 /*
-** $Id: ldebug.c,v 1.41 2000/09/12 18:38:02 roberto Exp roberto $
+** $Id: ldebug.c,v 1.42 2000/09/18 19:39:49 roberto Exp roberto $
 ** Debug Interface
 ** See Copyright Notice in lua.h
 */
@@ -433,7 +433,7 @@ static const char *getfuncname (lua_State *L, StkId f, const char **name) {
 void luaG_typeerror (lua_State *L, StkId o, const char *op) {
   const char *name;
   const char *kind = getobjname(L, o, &name);
-  const char *t = luaO_typename(o);
+  const char *t = luaO_typename(L, o);
   if (kind)
     luaO_verror(L, "attempt to %.30s %.20s `%.40s' (a %.10s value)",
                 op, kind, name, t);
@@ -442,7 +442,7 @@ void luaG_typeerror (lua_State *L, StkId o, const char *op) {
 }
 
 
-void luaG_binerror (lua_State *L, StkId p1, lua_Type t, const char *op) {
+void luaG_binerror (lua_State *L, StkId p1, lua_Tag t, const char *op) {
   if (ttype(p1) == t) p1++;
   LUA_ASSERT(ttype(p1) != t, "must be an error");
   luaG_typeerror(L, p1, op);
@@ -450,8 +450,8 @@ void luaG_binerror (lua_State *L, StkId p1, lua_Type t, const char *op) {
 
 
 void luaG_ordererror (lua_State *L, StkId top) {
-  const char *t1 = luaO_typename(top-2);
-  const char *t2 = luaO_typename(top-1);
+  const char *t1 = luaO_typename(L, top-2);
+  const char *t2 = luaO_typename(L, top-1);
   if (t1[2] == t2[2])
     luaO_verror(L, "attempt to compare two %.10s values", t1);
   else
diff --git a/ldebug.h b/ldebug.h
index eabad3d7..94baa17b 100644
--- a/ldebug.h
+++ b/ldebug.h
@@ -1,5 +1,5 @@
 /*
-** $Id: ldebug.h,v 1.4 2000/08/10 19:50:47 roberto Exp roberto $
+** $Id: ldebug.h,v 1.5 2000/08/11 16:17:28 roberto Exp roberto $
 ** Auxiliary functions from Debug Interface module
 ** See Copyright Notice in lua.h
 */
@@ -13,7 +13,7 @@
 
 
 void luaG_typeerror (lua_State *L, StkId o, const char *op);
-void luaG_binerror (lua_State *L, StkId p1, lua_Type t, const char *op);
+void luaG_binerror (lua_State *L, StkId p1, lua_Tag t, const char *op);
 int luaG_getline (int *lineinfo, int pc, int refline, int *refi);
 void luaG_ordererror (lua_State *L, StkId top);
 
diff --git a/ldo.c b/ldo.c
index ebf08346..90bb601b 100644
--- a/ldo.c
+++ b/ldo.c
@@ -1,5 +1,5 @@
 /*
-** $Id: ldo.c,v 1.98 2000/09/29 12:42:13 roberto Exp roberto $
+** $Id: ldo.c,v 1.99 2000/10/02 14:47:43 roberto Exp roberto $
 ** Stack and Call structure of Lua
 ** See Copyright Notice in lua.h
 */
@@ -332,7 +332,7 @@ struct lua_longjmp {
 
 static void message (lua_State *L, const char *s) {
   const TObject *em = luaH_getglobal(L, LUA_ERRORMESSAGE);
-  if (*luaO_typename(em) == 'f') {
+  if (luaO_type(em) == LUA_TFUNCTION) {
     *L->top = *em;
     incr_top;
     lua_pushstring(L, s);
diff --git a/liolib.c b/liolib.c
index 2b4e2f0e..c1453a19 100644
--- a/liolib.c
+++ b/liolib.c
@@ -1,5 +1,5 @@
 /*
-** $Id: liolib.c,v 1.84 2000/09/14 14:09:31 roberto Exp roberto $
+** $Id: liolib.c,v 1.85 2000/09/22 18:14:06 roberto Exp roberto $
 ** Standard I/O (and system) library
 ** See Copyright Notice in lua.h
 */
@@ -449,7 +449,7 @@ static int io_write (lua_State *L) {
   if (f) arg++;
   else f = getfilebyref(L, ctrl, OUTFILE);  /* get _OUTPUT */
   for (; arg <=  lastarg; arg++) {
-    if (lua_type(L, arg)[2] == 'm') {  /* nuMber? */  /* LUA_NUMBER */
+    if (lua_type(L, arg) == LUA_TNUMBER) {  /* LUA_NUMBER */
       /* optimization: could be done exactly as for strings */
       status = status && fprintf(f, "%.16g", lua_tonumber(L, arg)) > 0;
     }
diff --git a/lobject.c b/lobject.c
index 2256e953..9c478692 100644
--- a/lobject.c
+++ b/lobject.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lobject.c,v 1.48 2000/09/12 13:47:39 roberto Exp roberto $
+** $Id: lobject.c,v 1.49 2000/09/29 12:42:13 roberto Exp roberto $
 ** Some generic functions over Lua objects
 ** See Copyright Notice in lua.h
 */
@@ -17,16 +17,14 @@
 #include "lstate.h"
 
 
-/*
-** you can use the fact that the 3rd letter of each name is always different
-** (e-m-r-b-n-l) to compare and switch these strings
-*/
-const char *const luaO_typenames[] = { /* ORDER LUA_T */
-    "userdata", "number", "string", "table", "function", "function", "nil",
-    "function", "function"
+
+const lua_Type luaO_typearr[] = { /* ORDER LUA_T */
+  LUA_TUSERDATA, LUA_TNUMBER, LUA_TSTRING, LUA_TTABLE,
+  LUA_TFUNCTION, LUA_TFUNCTION, LUA_TNIL
 };
 
 
+
 const TObject luaO_nilobject = {TAG_NIL, {NULL}};
 
 
diff --git a/lobject.h b/lobject.h
index bd8a5a73..d6f667f4 100644
--- a/lobject.h
+++ b/lobject.h
@@ -1,5 +1,5 @@
 /*
-** $Id: lobject.h,v 1.76 2000/09/11 20:29:27 roberto Exp roberto $
+** $Id: lobject.h,v 1.77 2000/09/29 12:42:13 roberto Exp roberto $
 ** Type definitions for Lua objects
 ** See Copyright Notice in lua.h
 */
@@ -48,7 +48,7 @@ typedef enum {
   TAG_LMARK,    /* mark for Lua closures */
   TAG_CMARK     /* mark for C closures */
 
-} lua_Type;
+} lua_Tag;
 
 /* tags for values visible from Lua == first user-created tag */
 #define NUM_TAGS        7
@@ -80,7 +80,7 @@ typedef union {
 
 
 typedef struct lua_TObject {
-  lua_Type ttype;
+  lua_Tag ttype;
   Value value;
 } TObject;
 
@@ -189,10 +189,12 @@ typedef struct CallInfo {
 } CallInfo;
 
 
-extern const char *const luaO_typenames[];
+extern const lua_Type luaO_typearr[];
 extern const TObject luaO_nilobject;
 
-#define luaO_typename(o)        luaO_typenames[ttype(o)]
+#define luaO_tag2type(t)        (luaO_typearr[(int)(t)])
+#define luaO_type(o)            (luaO_tag2type(ttype(o)))
+#define luaO_typename(L, o)     (lua_typename(L, luaO_type(o)))
 
 lint32 luaO_power2 (lint32 n);
 char *luaO_openspace (lua_State *L, size_t n);
diff --git a/ltests.c b/ltests.c
index 49717a93..70cbd78f 100644
--- a/ltests.c
+++ b/ltests.c
@@ -1,5 +1,5 @@
 /*
-** $Id: ltests.c,v 1.45 2000/09/29 12:42:13 roberto Exp roberto $
+** $Id: ltests.c,v 1.46 2000/10/02 14:47:43 roberto Exp roberto $
 ** Internal Module for Debugging of the Lua Implementation
 ** See Copyright Notice in lua.h
 */
@@ -182,7 +182,7 @@ static int hash_query (lua_State *L) {
   }
   else {
     Hash *t;
-    luaL_checktype(L, 2, "table");
+    luaL_checktype(L, 2, LUA_TTABLE);
     t = hvalue(luaA_index(L, 2));
     lua_pushnumber(L, luaH_mainposition(t, luaA_index(L, 1)) - t->node);
   }
@@ -193,7 +193,7 @@ static int hash_query (lua_State *L) {
 static int table_query (lua_State *L) {
   const Hash *t;
   int i = luaL_opt_int(L, 2, -1);
-  luaL_checktype(L, 1, "table");
+  luaL_checktype(L, 1, LUA_TTABLE);
   t = hvalue(luaA_index(L, 1));
   if (i == -1) {
     lua_pushnumber(L, t->size);
@@ -238,7 +238,7 @@ static int string_query (lua_State *L) {
 
 
 static int tref (lua_State *L) {
-  luaL_checktype(L, 1, "any");
+  luaL_checkany(L, 1);
   lua_pushvalue(L, 1);
   lua_pushnumber(L, lua_ref(L, luaL_opt_int(L, 2, 1)));
   return 1;
@@ -262,7 +262,7 @@ static int newuserdata (lua_State *L) {
 }
 
 static int udataval (lua_State *L) {
-  luaL_checktype(L, 1, "userdata");
+  luaL_checktype(L, 1, LUA_TUSERDATA);
   lua_pushnumber(L, (int)lua_touserdata(L, 1));
   return 1;
 }
@@ -290,7 +290,7 @@ static int loadlib (lua_State *L) {
 }
 
 static int closestate (lua_State *L) {
-  luaL_checktype(L, 1, "userdata");
+  luaL_checktype(L, 1, LUA_TUSERDATA);
   lua_close((lua_State *)lua_touserdata(L, 1));
   return 0;
 }
@@ -299,7 +299,7 @@ static int doremote (lua_State *L) {
   lua_State *L1;
   const char *code = luaL_check_string(L, 2);
   int status;
-  luaL_checktype(L, 1, "userdata");
+  luaL_checktype(L, 1, LUA_TUSERDATA);
   L1 = (lua_State *)lua_touserdata(L, 1);
   status = lua_dostring(L1, code);
   if (status != 0) {
@@ -316,7 +316,7 @@ static int doremote (lua_State *L) {
 }
 
 static int settagmethod (lua_State *L) {
-  luaL_checktype(L, 3, "any");
+  luaL_checkany(L, 3);
   lua_settagmethod(L, luaL_check_int(L, 1), luaL_check_string(L, 2));
   return 1;
 }
@@ -436,7 +436,7 @@ static int testC (lua_State *L) {
       lua_dostring(L, luaL_check_string(L, getnum));
     }
     else if EQ("type") {
-      lua_pushstring(L, lua_type(L, getnum));
+      lua_pushstring(L, lua_typename(L, lua_type(L, getnum)));
     }
     else luaL_verror(L, "unknown instruction %.30s", buff);
   }
diff --git a/ltm.c b/ltm.c
index fd854d66..524b4fb2 100644
--- a/ltm.c
+++ b/ltm.c
@@ -1,5 +1,5 @@
 /*
-** $Id: ltm.c,v 1.49 2000/09/11 20:29:27 roberto Exp roberto $
+** $Id: ltm.c,v 1.50 2000/09/29 12:42:13 roberto Exp roberto $
 ** Tag methods
 ** See Copyright Notice in lua.h
 */
@@ -118,7 +118,7 @@ int lua_copytagmethods (lua_State *L, int tagto, int tagfrom) {
 
 
 int luaT_effectivetag (lua_State *L, const TObject *o) {
-  lua_Type t = ttype(o);
+  lua_Tag t = ttype(o);
   switch (t) {
     case TAG_USERDATA: {
       int tag = tsvalue(o)->u.d.tag;
@@ -151,7 +151,7 @@ void lua_settagmethod (lua_State *L, int t, const char *event) {
   checktag(L, t);
   if (!luaT_validevent(t, e))
     luaO_verror(L, "cannot change `%.20s' tag method for type `%.20s'%.20s",
-                luaT_eventname[e], luaO_typenames[t],
+                luaT_eventname[e], lua_typename(L, luaO_tag2type(t)),
                 (t == TAG_TABLE || t == TAG_USERDATA) ? " with default tag"
                                                           : "");
   temp = *(L->top - 1);
diff --git a/lua.h b/lua.h
index fcae18cf..5257ecc9 100644
--- a/lua.h
+++ b/lua.h
@@ -1,5 +1,5 @@
 /*
-** $Id: lua.h,v 1.70 2000/09/18 19:39:18 roberto Exp roberto $
+** $Id: lua.h,v 1.71 2000/10/02 14:47:43 roberto Exp roberto $
 ** Lua - An Extensible Extension Language
 ** TeCGraf: Grupo de Tecnologia em Computacao Grafica, PUC-Rio, Brazil
 ** e-mail: lua@tecgraf.puc-rio.br
@@ -48,6 +48,13 @@ typedef struct lua_State lua_State;
 typedef int (*lua_CFunction) (lua_State *L);
 
 
+typedef enum lua_Type {
+  LUA_NOVALUE, LUA_TUSERDATA, LUA_TNUMBER, LUA_TSTRING,
+  LUA_TTABLE, LUA_TFUNCTION, LUA_TNIL
+} lua_Type;
+
+
+
 /*
 ** state manipulation
 */
@@ -70,8 +77,10 @@ int            lua_stackspace (lua_State *L);
 ** access functions (stack -> C)
 */
 
-const char    *lua_type (lua_State *L, int index);
+lua_Type       lua_type (lua_State *L, int index);
+const char    *lua_typename (lua_State *L, lua_Type t);
 int            lua_isnumber (lua_State *L, int index);
+int            lua_isstring (lua_State *L, int index);
 int            lua_iscfunction (lua_State *L, int index);
 int            lua_tag (lua_State *L, int index);
 
@@ -171,12 +180,11 @@ void           lua_concat (lua_State *L, int n);
 #define lua_pushcfunction(L,f)  lua_pushcclosure(L, f, 0)
 #define lua_clonetag(L,t)       lua_copytagmethods(L, lua_newtag(L), (t))
 
-#define lua_isfunction(L,n)     (*lua_type(L,n) == 'f')
-#define lua_isstring(L,n)       (lua_tostring(L,n) != 0)
-#define lua_istable(L,n)        (*lua_type(L,n) == 't')
-#define lua_isuserdata(L,n)     (*lua_type(L,n) == 'u')
-#define lua_isnil(L,n)          (lua_type(L,n)[2] == 'l')
-#define lua_isnull(L,n)         (*lua_type(L,n) == 'N')
+#define lua_isfunction(L,n)     (lua_type(L,n) == LUA_TFUNCTION)
+#define lua_istable(L,n)        (lua_type(L,n) == LUA_TTABLE)
+#define lua_isuserdata(L,n)     (lua_type(L,n) == LUA_TUSERDATA)
+#define lua_isnil(L,n)          (lua_type(L,n) == LUA_TNIL)
+#define lua_isnull(L,n)         (lua_type(L,n) == LUA_NOVALUE)
 
 #endif
 
diff --git a/lvm.c b/lvm.c
index 8d058673..4eda5436 100644
--- a/lvm.c
+++ b/lvm.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lvm.c,v 1.137 2000/09/25 14:48:42 roberto Exp roberto $
+** $Id: lvm.c,v 1.138 2000/10/02 14:47:43 roberto Exp roberto $
 ** Lua virtual machine
 ** See Copyright Notice in lua.h
 */
@@ -85,7 +85,7 @@ static void traceexec (lua_State *L, StkId base, StkId top, lua_Hook linehook) {
 }
 
 
-static Closure *luaV_closure (lua_State *L, lua_Type t, int nelems) {
+static Closure *luaV_closure (lua_State *L, lua_Tag t, int nelems) {
   Closure *c = luaF_newclosure(L, nelems);
   L->top -= nelems;
   while (nelems--)