RE: [Python-Dev] The memo of pickle

7 Aug 2002

      [Tim]
...
The object's id() (address) is the key.  Else only hashable objects
could be pickled.
[Greg Ewing]
...
Hmmm, I see.
It occurs to me that what you really want here is a special
kind of dictionary that uses "is" instead of "==" to compare
key values.
Possibly.  The *effect* of that could be gotten via a wrapper object, like

class KeyViaId:
    def __init__(self, obj):
        self.obj = obj
    def __hash__(self):
        return hash(id(self.obj))
    def __eq__(self, other):
        return self.obj is other.obj

but if Martin is worried about two-tuple sizes, he's not going to fall in
love with that.
...
Or is that what was meant by an "identity dictionary"?
Guido asked, but if Martin answered that question I haven't seen it yet.

RE: [Python-Dev] The memo of pickle

Tim Peters