Added more readable __str__ and __repr__ methods to MergeDict.

Thanks, john@calixto.net. Fixed #3508.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@13721 bcc190cf-cafb-0310-a4f2-bffc1f526a37

AUTHORS

@@ -238,6 +238,7 @@ answer newbie questions, and generally made Django that much better:
     jcrasta@gmail.com
     jdetaeye
     jhenry <jhenry@theonion.com>
+    john@calixto.net
     Zak Johnson <zakj@nox.cx>
     Nis Jørgensen <nis@superlativ.dk>
     Michael Josephson <http://www.sdjournal.com/>

django/utils/datastructures.py

@@ -77,6 +77,27 @@ class MergeDict(object):
         """Returns a copy of this object."""
         return self.__copy__()
 
+    def __str__(self):
+        '''
+        Returns something like
+
+            "{'key1': 'val1', 'key2': 'val2', 'key3': 'val3'}"
+
+        instead of the generic "<object meta-data>" inherited from object.
+        '''
+        return str(dict(self.items()))
+
+    def __repr__(self):
+        '''
+        Returns something like
+
+            MergeDict({'key1': 'val1', 'key2': 'val2'}, {'key3': 'val3'})
+
+        instead of generic "<object meta-data>" inherited from object.
+        '''
+        dictreprs = ', '.join(repr(d) for d in self.dicts)
+        return '%s(%s)' % (self.__class__.__name__, dictreprs)
+
 class SortedDict(dict):
     """
     A dictionary that keeps its keys in the order in which they're inserted.