--- a/hgext/mq.py	Fri May 06 10:17:07 2011 -0500
+++ b/hgext/mq.py	Fri May 06 16:07:35 2011 +0300
@@ -45,7 +45,7 @@
 from mercurial.i18n import _
 from mercurial.node import bin, hex, short, nullid, nullrev
 from mercurial.lock import release
-from mercurial import commands, cmdutil, hg, patch, scmutil, util
+from mercurial import commands, cmdutil, hg, patch, scmutil, util, revset
 from mercurial import repair, extensions, url, error
 import os, sys, re, errno, shutil
 
@@ -3096,6 +3096,20 @@
         ui.note(_("mq:     (empty queue)\n"))
     return r
 
+def revsetmq(repo, subset, x):
+    """``mq()``
+    Changesets managed by MQ.
+    """
+    revset.getargs(x, 0, 0, _("mq takes no arguments"))
+    applied = set([repo[r.node].rev() for r in repo.mq.applied])
+    return [r for r in subset if r in applied]
+
+def extsetup(ui):
+    revset.symbols['mq'] = revsetmq
+
+# tell hggettext to extract docstrings from these functions:
+i18nfunctions = [revsetmq]
+
 def uisetup(ui):
     mqopt = [('', 'mq', None, _("operate on patch repository"))]
 

--- a/tests/test-mq.t	Fri May 06 10:17:07 2011 -0500
+++ b/tests/test-mq.t	Fri May 06 16:07:35 2011 +0300
@@ -843,6 +843,14 @@
   1 foo qbase
   2 bar qtip tip
 
+mq revset
+
+  $ hg log -r 'mq()' --template '{rev}\n'
+  1
+  2
+  $ hg help revsets | grep -i mq
+      "mq()"
+        Changesets managed by MQ.
 
 bad node in status