--- a/obsolete.py	Wed Sep 07 12:08:24 2011 +0200
+++ b/obsolete.py	Wed Sep 07 12:09:05 2011 +0200
@@ -8,6 +8,7 @@
 
 from mercurial import util
 from mercurial import context
+from mercurial import revset
 from mercurial.node import hex, bin
 
 # Patch changectx
@@ -27,6 +28,16 @@
     return ohidden(ctx)
 context.changectx.hidden = hidden
 
+# revset
+#############################
+
+def revsetobsolete(repo, subset, x):
+    args = revset.getargs(x, 0, 0, 'publicheads takes no arguments')
+    return [r for r in subset if repo[r].obsolete()] # XXX slow
+
+def extsetup(ui):
+    revset.symbols["obsolete"] = revsetobsolete
+
 # New commands
 #############################