PEP 802: Display Syntax for the Empty Set

[dg-pb]

@tjreedy

Then {-} for a set.

That is θ, not ∅.

@AlSweigart

The lack of syntax for an empty frozenset is a noticeable absence for me, so I’d rather not kick the can down the road.

Given there is already not enough syntax for frozenset, what is there left for frozendict ?

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Have the same concern.

Thus, created `frozenset`, `frozendict` comprehensions. Consideration .

Or if TLTR, it is essentially:

@Dutcho

mapping set
mutable {} {/}
frozen f{} f{/}

Which is at worst the fallback solution if there actually is not enough syntax.

And in the best case ends up something that is actually ok, given not needing to venture into {{...}} and its various complications.

I doubt this would be the best path if all 6 were being designed at the same time from the start, but it gives me peace of mind as such fallback is not too bad.

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I don’t mind {/} (voted for it) and I would be pleased if it turns out to fit well.

But given the above, I think it would be sensible not to rush with this and see what happens with frozenset and frozendict and try to manage this in parallel.