[Python-Dev] PEP 351, the freeze protocol

Christopher Armstrong radeex at gmail.com
Mon Oct 24 11:54:20 CEST 2005

On 10/24/05, Josiah Carlson <jcarlson at uci.edu> wrote:
> "Should dicts and sets automatically freeze their mutable keys?"
> Dictionaries don't have mutable keys,

Since when?

class Foo:
    def __init__(self):
        self.x = 1

f = Foo()
d = {f: 1}
f.x = 2

Maybe you meant something else? I can't think of any way in which
"dictionaries don't have mutable keys" is true. The only rule about
dictionary keys that I know of is that they need to be hashable and
need to be comparable with the equality operator.

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