Least unofficial enum support in python2.7 - flufl.enum or enum34?
enums, python, python-2.7
Solution
`enum34` matches what is in Python3.4, so that's the one to use.
The one big difference between the backport and 3.4's:
- In Python 2 you cannot get definition order (because `__prepare__` doesn't exist yet), but there is a work-around -- define `_order_` and it will be the "definition order" in Python 2 (it's simply ignored in Python 3). If you don't use the workaround the order used is the values of the members, in increasing order.
Update
the preferred spelling is now `_order_` (single instead of double leading and trailing underscores)
Python3.6+ will check that `_order_` matches the actual order (useful for keeping Python 2/3 code in sync)
1 Disclosure: I am the author of the Python stdlib `Enum`, the `enum34` backport , and the Advanced Enumeration (`aenum`) library.
Problem
Never thought I'd need to do this, but here I am intending to use enums in python 2.7. There is Barry's flufl.enum which PEP 435 says "...was the reference implementation upon which this PEP was originally based". But there is also a backport enum34 on pypi. These both seem semi-official, so which one should I use in new code? "There should be one obvious way to do it", but it's a hard topic to google for because there are dozens (hundreds?) of hand-rolled implementations out there. And the python 3.4 enum is still just a release candidate. I've tried out both `flufl.enum.Enum` and `enum34.Enum`, and the behaviour is quite different - most notably the differing semantics of `__getitem__`. According to this comment by Martijn Pieters, backport is/was challenging because implementation relies on the new `__prepare__` function on the metaclass. I've read this post and the PEP in entirety.