It does look like that would violate a basic property of `==` -- if two
values compare equal, they should be equally usable as dict keys. I can't
think of any counterexamples.
On Sat, May 2, 2020 at 1:33 PM Alex Hall <alex.moj...@gmail.com> wrote:
> On Sat, May 2, 2020 at 9:51 PM Serhiy Storchaka <storch...@gmail.com>
> wrote:
>
>> 02.05.20 21:34, Ahmed Amr пише:
>> > I see there are ways to compare them item-wise, I'm suggesting to bake
>> > that functionality inside the core implementation of such indexed
>> > structures.
>> > Also those solutions are direct with tuples and lists, but it wouldn't
>> > be as direct with arrays-lists/tuples comparisons for example.
>>
>> If make `(1, 2, 3) == [1, 2, 3]` we would need to make `hash((1, 2, 3))
>> == hash([1, 2, 3])`.
>>
>
> Would we? Is the contract `x == y => hash(x) == hash(y)` still required if
> hash(y) is an error? What situation involving dicts could lead to a bug if
> `(1, 2, 3) == [1, 2, 3]` but `hash((1, 2, 3))` is defined and `hash([1, 2,
> 3])` isn't?
>
> The closest example I can think of is that you might think you can do
> `{(1, 2, 3): 4}[[1, 2, 3]]`, but once you get `TypeError: unhashable type:
> 'list'` it'd be easy to fix.
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