Re: Read-Only Tables Patch

[Michael Grubb <lua@...>]

Doh!  So it is.

Here is the right way 'round.

--- CUT ---
diff -ruN lua-5.1.1/src/ltm.c lua-rot-5.1.1/src/ltm.c
--- lua-5.1.1/src/ltm.c	2006-01-10 06:50:00.000000000 -0600
+++ lua-rot-5.1.1/src/ltm.c	2006-11-10 15:39:56.000000000 -0600
@@ -30,8 +30,11 @@
void luaT_init (lua_State *L) {
   static const char *const luaT_eventname[] = {  /* ORDER TM */
     "__index", "__newindex",
-    "__gc", "__mode", "__eq",
-    "__add", "__sub", "__mul", "__div", "__mod",
+    "__gc", "__mode",
+#ifdef LUA_READONLY_TABLES
+	"__readonly",
+#endif
+	"__eq", "__add", "__sub", "__mul", "__div", "__mod",
     "__pow", "__unm", "__len", "__lt", "__le",
     "__concat", "__call"
   };
diff -ruN lua-5.1.1/src/ltm.h lua-rot-5.1.1/src/ltm.h
--- lua-5.1.1/src/ltm.h	2005-06-06 08:30:25.000000000 -0500
+++ lua-rot-5.1.1/src/ltm.h	2006-11-10 15:39:59.000000000 -0600
@@ -20,6 +20,9 @@
   TM_NEWINDEX,
   TM_GC,
   TM_MODE,
+#ifdef LUA_READONLY_TABLES
+  TM_READONLY,
+#endif
   TM_EQ,  /* last tag method with `fast' access */
   TM_ADD,
   TM_SUB,
diff -ruN lua-5.1.1/src/luaconf.h lua-rot-5.1.1/src/luaconf.h
--- lua-5.1.1/src/luaconf.h	2006-04-10 13:27:23.000000000 -0500
+++ lua-rot-5.1.1/src/luaconf.h	2006-11-10 15:39:47.000000000 -0600
@@ -747,6 +747,12 @@
#endif
+/*
+@@ LUA_READONLY_TABLES controls whether to enable read-only table
+support by way of the __readonly metatable entry. CHANGE it (define it)
+to enable Read-Only support.
+*/
+#define LUA_READONLY_TABLES
/*  
=================================================================== */
diff -ruN lua-5.1.1/src/lvm.c lua-rot-5.1.1/src/lvm.c
--- lua-5.1.1/src/lvm.c	2006-06-05 10:58:59.000000000 -0500
+++ lua-rot-5.1.1/src/lvm.c	2006-11-10 14:26:17.000000000 -0600
@@ -140,11 +140,22 @@
     if (ttistable(t)) {  /* `t' is a table? */
       Table *h = hvalue(t);
       TValue *oldval = luaH_set(L, h, key); /* do a primitive set */
+#ifdef LUA_READONLY_TABLES
+	  if ( (tm = fasttm(L, h->metatable, TM_READONLY)) != NULL )
+	  {
+		  if (ttisfunction(tm)) {
+			  callTM(L, tm, t, key, val);
+			  return;
+		  }
+		  else
+			  luaG_runerror(L, "Attempt to modify a Read-Only Table!");
+	  }
+#endif
       if (!ttisnil(oldval) ||  /* result is no nil? */
           (tm = fasttm(L, h->metatable, TM_NEWINDEX)) == NULL) { /*  
or no TM? */
-        setobj2t(L, oldval, val);
-        luaC_barriert(L, h, val);
-        return;
+        	setobj2t(L, oldval, val);
+        	luaC_barriert(L, h, val);
+        	return;
       }
       /* else will try the tag method */
     }
--- CUT ---

On Nov 13, 2006, at 9:48 AM, Alex Queiroz wrote:

> Hallo,
>
> On 11/13/06, Michael Grubb <lua@dailyvoid.com> wrote:
> > The patch is below:
>
>     I guess your patch is backwards.
>
> --
> -alex
> http://www.ventonegro.org/