diff options
Diffstat (limited to 'Lib/collections.py')
| -rw-r--r-- | Lib/collections.py | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/Lib/collections.py b/Lib/collections.py index 1126fb1..e849296 100644 --- a/Lib/collections.py +++ b/Lib/collections.py @@ -31,7 +31,9 @@ class OrderedDict(dict, MutableMapping): # The internal self.__map dictionary maps keys to links in a doubly linked list. # The circular doubly linked list starts and ends with a sentinel element. # The sentinel element never gets deleted (this simplifies the algorithm). - # The back links are weakref proxies (to prevent circular references). + # The prev/next links are weakref proxies (to prevent circular references). + # Individual links are kept alive by the hard reference in self.__map. + # Those hard references disappear when a key is deleted from an OrderedDict. def __init__(self, *args, **kwds): '''Initialize an ordered dictionary. Signature is the same as for @@ -60,8 +62,7 @@ class OrderedDict(dict, MutableMapping): root = self.__root last = root.prev link.prev, link.next, link.key = last, root, key - last.next = link - root.prev = proxy(link) + last.next = root.prev = proxy(link) dict.__setitem__(self, key, value) def __delitem__(self, key, dict_delitem=dict.__delitem__): |