Do you know what else would work for being able
to enter empty sets?
A prefix to {} , like "s"
a = s{}
and
b = f{}
for an empty frozenset
(/me ducks, and hides in a place Chris won't find me)
On Mon, Mar 14, 2022 at 10:29 AM Chris Angelico <ros...@gmail.com> wrote:
> On Tue, 15 Mar 2022 at 00:07, Joao S. O. Bueno <jsbu...@python.org.br>
> wrote:
> >
> >
> >
> > On Mon, Mar 14, 2022 at 9:49 AM Chris Angelico <ros...@gmail.com> wrote:
> >>
> >> On Mon, 14 Mar 2022 at 23:35, <joao.p.f.batista...@gmail.com> wrote:
> >> >
> >> > Currently:
> >> > l = [] # new empty list
> >> > t = () # new empty tuple
> >> > s = set() # new empty set (no clean and consistent way of
> initializing regarding the others) <<<
> >> > d = {} # new empty dictionary
> >> >
> >> > Possible solution:
> >> > s = {} # new empty set
> >> > d = {:} # new empty dictionary (the ":" is a reference to key-value
> pairs)
> >>
> >> Nope, that would break tons of existing code. Not gonna happen.
> >
> > Of couse not. (And I mean it).
> > - but what about keeping what exists and adding {,} for an empty set?
> > (it is not that unlike the one-element tuple, which already exists)
>
> That's more plausible. However, the one-element tuple is actually
> written like this:
>
> t = x,
>
> The parentheses are a common form of clarity (and included in the
> repr), but aren't actually the part of the syntax that makes it a
> tuple - the comma is. So there's no real parallel, and it's basically
> "what can we write that wouldn't be ambiguous?", which is a weak
> justification.
>
> Unfortunately, Python simply doesn't have enough symbols available.
> Using precisely one opener/closer for each type is highly limiting,
> since the only characters available are those on a US-English keyboard
> and in the ASCII set. It would be nice if, for instance, ∅ could mean
> "new empty set", but then we'd need a way to type it, and it'd end up
> coming right back around to "just type set(), it's easier".
>
> I wonder what it would be like to have a fork of Python that
> introduces some non-ASCII non-US-English syntax, purely to give people
> a chance to play around with it. Someone might actually set up an
> editor feature so that "set()" transforms into "∅", not just visually
> but in the file, and since it's restricted to an input feature in the
> editor, it avoids the usual problems of "what if you shadow the name
> set". Who knows? Maybe it would catch on, maybe it wouldn't.
>
> It's not all that difficult to hack on Python and add this feature. I
> did it a while back, but since I didn't use sets enough to bother
> figuring out an input method, didn't end up using it. If you want to
> write it as a pure source-code transformation, {*()} is a syntax-only
> way to generate an empty set, so it'll guarantee that you don't run
> into name shadowing issues; but it would be better to make it actual
> syntax (and thus avoid unpacking a tuple into your set for no reason),
> and also change the repr accordingly.
>
> ChrisA
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