diff --git a/Doc/tools/sphinxext/pyspecific.py b/Doc/tools/sphinxext/pyspecific.py
index 415310d..a588b4d 100644
--- a/Doc/tools/sphinxext/pyspecific.py
+++ b/Doc/tools/sphinxext/pyspecific.py
@@ -5,11 +5,12 @@
 
     Sphinx extension with Python doc-specific markup.
 
-    :copyright: 2008, 2009 by Georg Brandl.
+    :copyright: 2008-2011 by Georg Brandl.
     :license: Python license.
 """
 
 ISSUE_URI = 'http://bugs.python.org/issue%s'
+SOURCE_URI = 'http://hg.python.org/cpython/file/2.7/%s'
 
 from docutils import nodes, utils
 
@@ -44,6 +45,14 @@
     return [refnode], []
 
 
+# Support for linking to Python source files easily
+
+def source_role(typ, rawtext, text, lineno, inliner, options={}, content=[]):
+    path = utils.unescape(text)
+    refnode = nodes.reference(path, path, refuri=SOURCE_URI % path)
+    return [refnode], []
+
+
 # Support for marking up implementation details
 
 from sphinx.util.compat import Directive
@@ -168,6 +177,7 @@
 
 def setup(app):
     app.add_role('issue', issue_role)
+    app.add_role('source', source_role)
     app.add_directive('impl-detail', ImplementationDetail)
     app.add_builder(PydocTopicsBuilder)
     app.add_builder(suspicious.CheckSuspiciousMarkupBuilder)