'luaL_getmetafield' returns type of metafield (instead of a boolean)

lauxlib.c

@@ -1,5 +1,5 @@
 /*
-** $Id: lauxlib.c,v 1.266 2014/07/17 12:30:53 roberto Exp roberto $
+** $Id: lauxlib.c,v 1.267 2014/07/19 14:37:09 roberto Exp roberto $
 ** Auxiliary functions for building Lua libraries
 ** See Copyright Notice in lua.h
 */
@@ -170,13 +170,13 @@ LUALIB_API int luaL_argerror (lua_State *L, int arg, const char *extramsg) {
 
 static int typeerror (lua_State *L, int arg, const char *tname) {
   const char *msg;
-  const char *typearg = luaL_typename(L, arg);
-  if (lua_getmetatable(L, arg)) {
-    if (lua_getfield(L, -1, "__name") == LUA_TSTRING)
-      typearg = lua_tostring(L, -1);
-  }
+  const char *typearg;  /* name for the type of the actual argument */
+  if (luaL_getmetafield(L, arg, "__name") == LUA_TSTRING)
+    typearg = lua_tostring(L, -1);  /* use the given type name */
   else if (lua_type(L, arg) == LUA_TLIGHTUSERDATA)
-    typearg = "light userdata";
+    typearg = "light userdata";  /* special name for messages */
+  else
+    typearg = luaL_typename(L, arg);  /* standard name */
   msg = lua_pushfstring(L, "%s expected, got %s", tname, typearg);
   return luaL_argerror(L, arg, msg);
 }
@@ -701,22 +701,23 @@ LUALIB_API int luaL_loadstring (lua_State *L, const char *s) {
 
 LUALIB_API int luaL_getmetafield (lua_State *L, int obj, const char *event) {
   if (!lua_getmetatable(L, obj))  /* no metatable? */
-    return 0;
+    return LUA_TNIL;
+  else {
+    int tt;
     lua_pushstring(L, event);
-  if (lua_rawget(L, -2) == LUA_TNIL) {  /* is metafield nil? */
+    tt = lua_rawget(L, -2);
+    if (tt == LUA_TNIL)  /* is metafield nil? */
       lua_pop(L, 2);  /* remove metatable and metafield */
-    return 0;
-  }
-  else {
+    else
       lua_remove(L, -2);  /* remove only metatable */
-    return 1;
+    return tt;  /* return metafield type */
   }
 }
 
 
 LUALIB_API int luaL_callmeta (lua_State *L, int obj, const char *event) {
   obj = lua_absindex(L, obj);
-  if (!luaL_getmetafield(L, obj, event))  /* no metafield? */
+  if (luaL_getmetafield(L, obj, event) == LUA_TNIL)  /* no metafield? */
     return 0;
   lua_pushvalue(L, obj);
   lua_call(L, 1, 1);

lbaselib.c

@@ -1,5 +1,5 @@
 /*
-** $Id: lbaselib.c,v 1.295 2014/08/01 17:33:08 roberto Exp roberto $
+** $Id: lbaselib.c,v 1.296 2014/08/21 20:07:56 roberto Exp roberto $
 ** Basic library
 ** See Copyright Notice in lua.h
 */
@@ -129,7 +129,7 @@ static int luaB_setmetatable (lua_State *L) {
   luaL_checktype(L, 1, LUA_TTABLE);
   luaL_argcheck(L, t == LUA_TNIL || t == LUA_TTABLE, 2,
                     "nil or table expected");
-  if (luaL_getmetafield(L, 1, "__metatable"))
+  if (luaL_getmetafield(L, 1, "__metatable") != LUA_TNIL)
     return luaL_error(L, "cannot change a protected metatable");
   lua_settop(L, 2);
   lua_setmetatable(L, 1);
@@ -212,7 +212,7 @@ static int luaB_type (lua_State *L) {
 
 static int pairsmeta (lua_State *L, const char *method, int iszero,
                       lua_CFunction iter) {
-  if (!luaL_getmetafield(L, 1, method)) {  /* no metamethod? */
+  if (luaL_getmetafield(L, 1, method) == LUA_TNIL) {  /* no metamethod? */
     luaL_checktype(L, 1, LUA_TTABLE);  /* argument must be a table */
     lua_pushcfunction(L, iter);  /* will return generator, */
     lua_pushvalue(L, 1);  /* state, */
@@ -279,8 +279,8 @@ static int ipairsaux (lua_State *L) {
 */
 static int luaB_ipairs (lua_State *L) {
   lua_CFunction iter =
-     (luaL_getmetafield(L, 1, "__len") ||
-      luaL_getmetafield(L, 1, "__index"))
+     (luaL_getmetafield(L, 1, "__len") != LUA_TNIL ||
+      luaL_getmetafield(L, 1, "__index") != LUA_TNIL)
         ? ipairsaux : ipairsaux_raw;
 #if defined(LUA_COMPAT_IPAIRS)
   return pairsmeta(L, "__ipairs", 1, iter);

ltablib.c

@@ -1,5 +1,5 @@
 /*
-** $Id: ltablib.c,v 1.74 2014/08/21 19:13:55 roberto Exp roberto $
+** $Id: ltablib.c,v 1.75 2014/08/21 20:07:56 roberto Exp roberto $
 ** Library for Table Manipulation
 ** See Copyright Notice in lua.h
 */
@@ -126,10 +126,10 @@ static int tmove (lua_State *L) {
   luaL_argcheck(L, f > 0, 2, "initial position must be positive");
   if (e >= f) {  /* otherwise, nothing to move */
     lua_Integer n, i;
-    ta.geti = (!luaL_getmetafield(L, 1, "__index"))
+    ta.geti = (luaL_getmetafield(L, 1, "__index") == LUA_TNIL)
       ? (luaL_checktype(L, 1, LUA_TTABLE), lua_rawgeti)
       : lua_geti;
-    ta.seti = (!luaL_getmetafield(L, tt, "__newindex"))
+    ta.seti = (luaL_getmetafield(L, tt, "__newindex") == LUA_TNIL)
       ? (luaL_checktype(L, tt, LUA_TTABLE), lua_rawseti)
       : lua_seti;
     n = e - f + 1;  /* number of elements to move */