a small optimization

ltm.h

@@ -1,5 +1,5 @@
 /*
-** $Id: ltm.h,v 1.19 2000/12/26 18:46:09 roberto Exp roberto $
+** $Id: ltm.h,v 1.20 2001/01/19 13:20:30 roberto Exp roberto $
 ** Tag methods
 ** See Copyright Notice in lua.h
 */
@@ -35,6 +35,21 @@ typedef enum {
 } TMS;
 
 
+
+/*
+** masks for allowable tag methods
+*/
+#define HAS_TM_GETGLOBAL(L,t)	(1<<(t) & ((1<<LUA_TUSERDATA) | \
+                                           (1<<LUA_TTABLE) | \
+                                           (1<<LUA_TNIL)))
+
+#define HAS_TM_SETGLOBAL(L,t)	(1<<(t) & ((1<<LUA_TUSERDATA) | \
+                                           (1<<LUA_TTABLE) | \
+                                           (1<<LUA_TNIL) | \
+                                           (1<<LUA_TFUNCTION)))
+
+
+
 struct TM {
   Closure *method[TM_N];
   TString *collected;  /* list of garbage-collected udata with this tag */