Have pprint() respect the order in an OrderedDict.

Lib/pprint.py

@@ -35,7 +35,7 @@
 """
 
 import sys as _sys
-
+from collections import OrderedDict as _OrderedDict
 from io import StringIO as _StringIO
 
 __all__ = ["pprint","pformat","isreadable","isrecursive","saferepr",
@@ -163,7 +163,7 @@ def _format(self, object, stream, indent, allowance, context, level):
 
         if sepLines:
             r = getattr(typ, "__repr__", None)
-            if issubclass(typ, dict) and r is dict.__repr__:
+            if issubclass(typ, dict):
                 write('{')
                 if self._indent_per_level > 1:
                     write((self._indent_per_level - 1) * ' ')
@@ -171,7 +171,10 @@ def _format(self, object, stream, indent, allowance, context, level):
                 if length:
                     context[objid] = 1
                     indent = indent + self._indent_per_level
-                    items  = sorted(object.items(), key=_safe_tuple)
+                    if issubclass(typ, _OrderedDict):
+                        items = list(object.items())
+                    else:
+                        items = sorted(object.items(), key=_safe_tuple)
                     key, ent = items[0]
                     rep = self._repr(key, context, level)
                     write(rep)

Lib/test/test_pprint.py

@@ -3,6 +3,8 @@
 import unittest
 import test.test_set
 import random
+import collections
+import itertools
 
 # list, tuple and dict subclasses that do or don't overwrite __repr__
 class list2(list):
@@ -195,6 +197,20 @@ def test_sorted_dict(self):
         self.assertEqual(pprint.pformat({"xy\tab\n": (3,), 5: [[]], (): {}}),
             r"{5: [[]], 'xy\tab\n': (3,), (): {}}")
 
+    def test_ordered_dict(self):
+        words = 'the quick brown fox jumped over a lazy dog'.split()
+        d = collections.OrderedDict(zip(words, itertools.count()))
+        self.assertEqual(pprint.pformat(d),
+"""\
+{'the': 0,
+ 'quick': 1,
+ 'brown': 2,
+ 'fox': 3,
+ 'jumped': 4,
+ 'over': 5,
+ 'a': 6,
+ 'lazy': 7,
+ 'dog': 8}""")
     def test_subclassing(self):
         o = {'names with spaces': 'should be presented using repr()',
              'others.should.not.be': 'like.this'}

Misc/NEWS

@@ -16,6 +16,9 @@ Core and Builtins
 Library
 -------
 
+- The pprint module now supports printing OrderedDicts in their given
+  order (formerly, it would sort the keys).
+
 - Logging: Added QueueHandler class to facilitate logging usage with
   multiprocessing.