On Sun, Jan 16, 2022 at 05:53:19PM -0800, Brendan Barnwell wrote:
> > f{1, 2, 3}
>
> I don't like that syntax. In the first place, as others have noted,
> it treads too close to existing function-call and indexing syntax. In
> those syntaxes, `f` is a name, whereas here it is not a name but just a
> syntactic marker (as in f-strings).
I think the horse has well and truly bolted on that. We've had syntactic
markers that look like names forever: r"" goes back to Python 1.x days.
Given the proposed syntax `f{a, b, c}`, that would be a transformation
of three arguments a, b and c to a frozenset. That makes it closer to a
function call than r"abc", which is not a transformation at all.
So if this looks like a function call, good, that's because semantically
it is kind of like a function call.
> In the second place, I don't like the idea of using prefixes to
> change the types of objects like this. As far as I know we only have
> one
> example of that, namely byte strings.
Okay, so we have a precedence where a prefix on the delimiter changes
the type: b'' is a different type to ''. In Python 2, it was the other
way around, it was u'' that returned a different type.
I think that the use of a prefix has been a moderately good design, good
enough to cautiously extend it beyond raw strings to unicode strings,
f-strings, and byte-strings, and beyond that to other delimiters.
But if you think that the difference between '' and b'' is a terrible
design flaw that has caused all sorts of badness in Python 3, I'm all
ears. Please explain, and persuade me.
> I would prefer some sort of augmented bracket notation, like {:1, 2,
> 3:} or something along those lines.
You don't think that people will associate {:1, 2:} with badly-written
dicts rather than sets? If not, is there some sort of mental association
between frozensets and those colons inside the set syntax?
--
Steve
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