--- a/mercurial/cmdutil.py	Mon Mar 08 11:12:48 2010 -0600
+++ b/mercurial/cmdutil.py	Mon Mar 08 19:43:24 2010 +0100
@@ -660,6 +660,46 @@
     if runfn:
         return runfn()
 
+def export(repo, revs, template='hg-%h.patch', fp=None, switch_parent=False,
+           opts=None):
+    '''export changesets as hg patches.'''
+
+    total = len(revs)
+    revwidth = max([len(str(rev)) for rev in revs])
+
+    def single(rev, seqno, fp):
+        ctx = repo[rev]
+        node = ctx.node()
+        parents = [p.node() for p in ctx.parents() if p]
+        branch = ctx.branch()
+        if switch_parent:
+            parents.reverse()
+        prev = (parents and parents[0]) or nullid
+
+        if not fp:
+            fp = make_file(repo, template, node, total=total, seqno=seqno,
+                           revwidth=revwidth, mode='ab')
+        if fp != sys.stdout and hasattr(fp, 'name'):
+            repo.ui.note("%s\n" % fp.name)
+
+        fp.write("# HG changeset patch\n")
+        fp.write("# User %s\n" % ctx.user())
+        fp.write("# Date %d %d\n" % ctx.date())
+        if branch and (branch != 'default'):
+            fp.write("# Branch %s\n" % branch)
+        fp.write("# Node ID %s\n" % hex(node))
+        fp.write("# Parent  %s\n" % hex(prev))
+        if len(parents) > 1:
+            fp.write("# Parent  %s\n" % hex(parents[1]))
+        fp.write(ctx.description().rstrip())
+        fp.write("\n\n")
+
+        for chunk in patch.diff(repo, prev, node, opts=opts):
+            fp.write(chunk)
+
+    for seqno, rev in enumerate(revs):
+        single(rev, seqno + 1, fp)
+
 class changeset_printer(object):
     '''show changeset information when templating not requested.'''