Merged revisions 62080-62262 via svnmerge from

svn+ssh://pythondev@svn.python.org/sandbox/trunk/2to3/lib2to3

........
  r62092 | collin.winter | 2008-04-01 18:27:10 +0200 (Di, 01 Apr 2008) | 1 line

  Add get_prev_sibling() to complement pytree's get_next_sibling().
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  r62226 | collin.winter | 2008-04-08 21:07:56 +0200 (Di, 08 Apr 2008) | 1 line

  Add min() and max() to the list of special contexts that don't require adding list() calls around dict methods.
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  r62232 | collin.winter | 2008-04-09 00:12:38 +0200 (Mi, 09 Apr 2008) | 4 lines

  Fix for http://bugs.python.org/issue2596

  This extends fix_xrange to know about the (mostly) same special contexts as fix_dict (where a special context is something that is guaranteed to fully consume the iterable), adding list() calls where appropriate. It also special-cases "x in range(y)".
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1 files changed, 16 insertions, 2 deletions

diff --git a/Lib/lib2to3/pytree.py b/Lib/lib2to3/pytree.py
index 8b6780afdb..18a2de34f2 100644
--- a/Lib/lib2to3/pytree.py
+++ b/Lib/lib2to3/pytree.py
@@ -167,13 +167,27 @@ class Base(object):
             return None
 
         # Can't use index(); we need to test by identity
-        for i, sibling in enumerate(self.parent.children):
-            if sibling is self:
+        for i, child in enumerate(self.parent.children):
+            if child is self:
                 try:
                     return self.parent.children[i+1]
                 except IndexError:
                     return None
 
+    def get_prev_sibling(self):
+        """Return the node immediately preceding the invocant in their
+        parent's children list. If the invocant does not have a previous
+        sibling, return None."""
+        if self.parent is None:
+            return None
+
+        # Can't use index(); we need to test by identity
+        for i, child in enumerate(self.parent.children):
+            if child is self:
+                if i == 0:
+                    return None
+                return self.parent.children[i-1]
+
     def get_suffix(self):
         """Return the string immediately following the invocant node. This
         is effectively equivalent to node.get_next_sibling().get_prefix()"""