[Python-3000] Set literal

[Gustavo Niemeyer]

> I hope it isn't too confusing that {1: 1} creates a *mutable* dict
> while {1} creates an *immutable* frozenset. I still find this slightly
> inelegant. But the practicality of being able to treat set literals as
> compile-time constants wins me over.

Another point in favor of Raymond's suggestion is that problems created
by getting it wrong in the first try are more easily solved when going
frozenset => set than the opposite way.

-- 
Gustavo Niemeyer
http://niemeyer.net