--- a/mercurial/help/revsets.txt	Sun Oct 10 12:41:36 2010 -0500
+++ b/mercurial/help/revsets.txt	Mon Oct 11 09:44:19 2010 -0500
@@ -94,6 +94,9 @@
 ``heads(set)``
   Members of set with no children in set.
 
+``id(string)``
+  Revision non-ambiguously specified by the given hex string prefix
+
 ``keyword(string)``
   Search commit message, user name, and names of changed files for
   string.
@@ -133,6 +136,9 @@
 ``removes(pattern)``
   Changesets which remove files matching pattern.
 
+``rev(number)``
+  Revision with the given numeric identifier.
+
 ``reverse(set)``
   Reverse order of set.
 

--- a/mercurial/revset.py	Sun Oct 10 12:41:36 2010 -0500
+++ b/mercurial/revset.py	Mon Oct 11 09:44:19 2010 -0500
@@ -173,6 +173,23 @@
 
 # functions
 
+def node(repo, subset, x):
+    l = getargs(x, 1, 1, _("rev wants one argument"))
+    n = getstring(l[0], _("rev wants a string"))
+    if len(n) == 40:
+        rn = repo[n].rev()
+    else:
+        rn = repo.changelog.rev(repo.changelog._partialmatch(n))
+    return [r for r in subset if r == rn]
+
+def rev(repo, subset, x):
+    l = getargs(x, 1, 1, _("rev wants one argument"))
+    try:
+        l = int(getstring(l[0], _("rev wants a number")))
+    except ValueError:
+        raise error.ParseError(_("rev expects a number"))
+    return [r for r in subset if r == l]
+
 def p1(repo, subset, x):
     ps = set()
     cl = repo.changelog
@@ -501,6 +518,7 @@
     "min": minrev,
     "merge": merge,
     "modifies": modifies,
+    "id": node,
     "outgoing": outgoing,
     "p1": p1,
     "p2": p2,
@@ -508,6 +526,7 @@
     "present": present,
     "removes": removes,
     "reverse": reverse,
+    "rev": rev,
     "roots": roots,
     "sort": sort,
     "tag": tag,

--- a/tests/test-revset.t	Sun Oct 10 12:41:36 2010 -0500
+++ b/tests/test-revset.t	Mon Oct 11 09:44:19 2010 -0500
@@ -247,6 +247,8 @@
   6
   $ log 'modifies(b)'
   4
+  $ log 'id(5)'
+  2
   $ log 'outgoing()'
   8
   9
@@ -276,6 +278,8 @@
   4
   3
   2
+  $ log 'rev(5)'
+  5
   $ log 'sort(limit(reverse(all()), 3))'
   7
   8