[Python-ideas] Enums

[Michael Foord]

On 27 July 2011 13:44, M.-A. Lemburg <mal at egenix.com> wrote:

> Raymond Hettinger wrote:
> >
> > On Jul 24, 2011, at 6:19 PM, Jack Diederich wrote:
> >
> >> On Sun, Jul 24, 2011 at 8:33 PM, Guido van Rossum <guido at python.org>
> wrote:
> >>> For enums, I think we should just pick a solution. I'm in favor of
> >>> Barry Warsaw's version, flufl.enum.
> >>
> >> I don't care for enums but enough other people do that I wouldn't mind
> >> including a blessed implemenation.
> >
> > I also don't care for enums and recommend against adding them to the
> language.
> > IMO, it is something that makes good sense in statically compiled
> languages
> > and is unnecessary for us.  Not to mention, we already have several ways
> to do it
> > (module and class namespaces for example).
> >
> > Also, when this idea came up in the past, it tended to get shot down
> because
> > the various use cases suggested differing implementations with different
> > features.
> >
> > I also urge caution because Python has already stopped being a small
> language.
> > Enums are especially problematic because they will pop up everywhere.
> > You won't have the option of ignoring them.
>
> +1
>
>
Actually, as they should behave exactly like constants you should entirely
be able to "ignore" them (to the same extent you ignore the existing
constants anyway).

Whether they're exposed at the module level, or grouped in a single
namespace (the container), or both, is a stylistic issue for module authors.
I've seen plenty of Python modules that group constants as class attributes
for convenience even without an enum in the standard library. This proposal
just makes those more useful and doesn't add any overhead for *using* them.

I think a lot of the objections come from perceived negative experience of
Enums in other languages (not particularly aimed at you here MAL). When we
discussed this on python-dev several developers were much happier with the
proposal if we called them NamedConstants and GroupedConstants rather than
Enums.

Michael



> > Python has achieved an amazing adoption rate without enums.
> > Most people just don't need them.  Many, large and clean apps have
> > been built without them.  Those that have found did were typically
> > able to implement them easily with the existing toolset.
>
> --
> Marc-Andre Lemburg
> eGenix.com
>
> Professional Python Services directly from the Source  (#1, Jul 27 2011)
> >>> Python/Zope Consulting and Support ...        http://www.egenix.com/
> >>> mxODBC.Zope.Database.Adapter ...             http://zope.egenix.com/
> >>> mxODBC, mxDateTime, mxTextTools ...        http://python.egenix.com/
> ________________________________________________________________________
>
> ::: Try our new mxODBC.Connect Python Database Interface for free ! ::::
>
>
>   eGenix.com Software, Skills and Services GmbH  Pastor-Loeh-Str.48
>    D-40764 Langenfeld, Germany. CEO Dipl.-Math. Marc-Andre Lemburg
>           Registered at Amtsgericht Duesseldorf: HRB 46611
>               http://www.egenix.com/company/contact/
> _______________________________________________
> Python-ideas mailing list
> Python-ideas at python.org
> http://mail.python.org/mailman/listinfo/python-ideas
>



-- 

http://www.voidspace.org.uk/

May you do good and not evil
May you find forgiveness for yourself and forgive others
May you share freely, never taking more than you give.
-- the sqlite blessing http://www.sqlite.org/different.html
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.python.org/pipermail/python-ideas/attachments/20110727/216d41d3/attachment.html>