--- a/hgext3rd/topic/__init__.py	Tue Mar 15 17:26:57 2016 +0000
+++ b/hgext3rd/topic/__init__.py	Mon Mar 14 18:39:19 2016 +0000
@@ -12,6 +12,7 @@
 """
 import functools
 import contextlib
+import re
 
 from mercurial.i18n import _
 from mercurial import branchmap
@@ -51,7 +52,22 @@
     return self.extra().get(constants.extrakey, '')
 context.basectx.topic = _contexttopic
 
+topicrev = re.compile(r'^t\d+$')
+
+
 def _namemap(repo, name):
+    if topicrev.match(name):
+        idx = int(name[1:])
+        topic = repo.currenttopic
+        if not topic:
+            raise error.Abort(_('cannot resolve "%s": no active topic') % name)
+        revs = list(stack.getstack(repo, topic))
+        try:
+            r = revs[idx]
+        except IndexError:
+            msg = _('cannot resolve "%s": topic "%s" has only %d changesets')
+            raise error.Abort(msg % (name, topic, len(revs)))
+        return [repo[r].node()]
     return [ctx.node() for ctx in
             repo.set('not public() and extra(topic, %s)', name)]