One implementation detail that I think needs further consideration is in which way to expose the keys and to mix in list methods for ordered dictionaries.
In http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/107747 the keys are exposed via the keys() method which is bad. It should be a copy only, like for ordinary dicts (one comment also mentions that). In Foord/Larosa's odict, the keys are exposed as a public member which also seems to be a bad idea ("If you alter the sequence list so that it no longer reflects the contents of the dictionary, you have broken your OrderedDict"). I think it would be probably the best to hide the keys list from the public, but to provide list methods for reordering them (sorting, slicing etc.). For instance: d1 = OrderedDict( (1, 11), (2, 12), 3, 13) ) d1[1:] ==> OrderedDict( (2, 12), 3, 13) ) d1[0] + d1[2] ==> OrderedDict( (1, 11), (3, 13) ) d1.reverse() ==> OrderedDict( (3, 13), (2, 12), 1, 11) ) d1.insert(1, (4, 14)) ==> OrderedDict( (1, 11), (4, 14), (2, 12), 3, 13) ) etc. But no other way to directly manipulate the keys should be provided. -- Christoph -- http://mail.python.org/mailman/listinfo/python-list
