(-compare:, -shouldNotImplement:): Added.

From-SVN: r5399

gcc/objc/Object.h

@@ -61,6 +61,7 @@ the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
 - - self;
 - (unsigned int)hash;
 - (BOOL)isEqual:anObject;
+- (int)compare:anotherObject;
 
         /* Testing object type */
 - (BOOL)isMetaClass;
@@ -102,6 +103,7 @@ the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
         /* Enforcing intentions */
 - - subclassResponsibility:(SEL)aSel;
 - - notImplemented:(SEL)aSel;
+- - shouldNotImplement:(SEL)aSel;
 
         /* Error handling */
 - - doesNotRecognize:(SEL)aSel;

gcc/objc/Object.m

@@ -116,6 +116,18 @@ extern int errno;
   return self==anObject;
 }
 
+- (int)compare:anotherObject;
+{
+  if ([self isEqual:anotherObject])
+    return 0;
+  // Ordering objects by their address is pretty useless, 
+  // so subclasses should override this is some useful way.
+  else if (self > anotherObject)
+    return 1;
+  else 
+    return -1;
+}
+
 - (BOOL)isMetaClass
 {
   return NO;
@@ -287,6 +299,12 @@ extern int errno;
   return [self error:"method %s not implemented", sel_get_name(aSel)];
 }
 
+- shouldNotImplement:(SEL)aSel
+{
+  return [self error:"%s should not implement %s", 
+	             object_get_class_name(self), sel_get_name(aSel)];
+}
+
 - doesNotRecognize:(SEL)aSel
 {
   return [self error:"%s does not recognize %s",