of course it’s ugly, but it’s also obvious that it had to be suggested, because it’s the only obvious idea.

which leaves us with either a non-obvious idea or no empty set literal, which is a bit sad and inconsistent.

if i’d develop a language from scratch, i’d possibly use the following empty literals:

[] = list; () = tuple, {} = set
[:] = ordered dict, (:) = named tuple, {:} = dict

but that ship has sailed.


2014-06-10 18:39 GMT+02:00 Guido van Rossum <guido@python.org>:
No. Jeez. :-(


On Tue, Jun 10, 2014 at 9:25 AM, Ryan Gonzalez <rymg19@gmail.com> wrote:
+1 for using {,}.


On Tue, Jun 10, 2014 at 4:07 AM, Wichert Akkerman <wichert@wiggy.net> wrote:
Victor Stinner wrote:
2014-06-10 8:15 GMT+02:00 Neil Girdhar <mistersheik at gmail.com>:

> I've seen this proposed before, and I personally would love this, but my
> guess is that it breaks too much code for too little gain.
>
> On Wednesday, May 21, 2014 12:33:30 PM UTC-4, Frédéric Legembre wrote:
>>
>>
>>    Now   |  Future  |
>> ----------------------------------------------------
>>    ()    |   ()     |  empty tuple  ( 1, 2, 3 )
>>    []    |   []     |  empty list   [ 1, 2, 3 ]
>>    set() |   {}     |  empty set    { 1, 2, 3 }
>>    {}    |   {:}    |  empty dict   { 1:a, 2:b, 3:c }


Your guess is right. It will break all Python 2 and Python 3 in the world.

Technically, set((1, 2)) is different than {1, 2}: the first creates a
tuple and loads the global name "set" (which can be replaced at
runtime!), whereas the later uses bytecode and only store values
(numbers 1 and 2).

It would be nice to have a syntax for empty set, but {} is a no-no.

Perhaps {,} would be a possible spelling. For consistency you might want to allow (,) to create an empty tuple as well; personally I would find that more intuitive that (()).
Wichert.
 


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