[Python-ideas] constant/enum type in stdlib

[Giampaolo Rodolà]

2013/1/30 Eli Bendersky <eliben at gmail.com>:
>
>
>
> On Wed, Jan 30, 2013 at 8:27 AM, Barry Warsaw <barry at python.org> wrote:
>>
>> On Jan 30, 2013, at 08:17 AM, Eli Bendersky wrote:
>>
>> >Barry, since you've obviously given this issue a lot of thought, maybe
>> > you
>> >could summarize it in a PEP so we have a clear way of moving forward for
>> >3.4 ?
>>
>> I'm happy to do so if there's a realistic chance of it being accepted.  We
>> already have one rejected enum PEP (354) and we probably don't need two.
>> ;)
>>
>
> Reading this thread it seems that many core devs are interested in the
> feature and the discussion is mainly deciding on the exact semantics and
> implementation. Even Guido didn't really speak against it (only somewhat
> against adding new syntax).
>
> Eli


Personally I'm -1 for a variety of reasons.

1) a const/enum type looks like something which is subject to personal
taste to me. I personally don't like, for example, how flufl requires
to define constants by using a class.
It's just a matter of taste but to me module.FOO looks more "right"
than module.Bar.FOO.
Also "Colors.red < Colors.blue" raising an exception is something
subject to personal taste.

2) introducing something like that (class-based) wouldn't help
migrating the existent module-level constants we have in the stdlib.
Only new projects or new stdlib modules would benefit from it.

3) other than being subject to personal taste, a const/enum type is
also pretty easy to implement.
For example, I came up with this:
http://code.google.com/p/psutil/source/browse/trunk/psutil/_common.py?spec=svn1562&r=1524#33
...which is sufficient for my needs.
Users having different needs can do a similar thing pretty easily.

4) I'm getting the impression that the language is growing too big. To
me, this looks like yet another thing that infrequent users have to
learn before being able to read and understand Python code.
Also consider that people lived without const/enum for 2 decades now.


--- Giampaolo
http://code.google.com/p/pyftpdlib/
http://code.google.com/p/psutil/
http://code.google.com/p/pysendfile/