[Python-Dev] PEP520 and absence of __definition_order__

[Victor Stinner]

2016-09-10 3:49 GMT-04:00 Ethan Furman <ethan at stoneleaf.us>:
> With __definition_order__ Enum can display the actual creation order of enum
> members and methods, while relying on Enum.__dict__.keys() presents a
> jumbled mess with many attributes the user never wrote, the enum members either
> appearing /after/ all the methods (even if actually written before), or
> entirely absent.

Python 3.5 also returns methods in Enum.__dict__(). So it would be a
new feature, right?

The use case seems to be specific to Enum. Can't you add a new method
which only returns members (ordered by insertion order)?

list(myenum._member_maps.keys()) returns members, sorted by insertion
order. Is it what you want?

Code:
---
import enum

class Color(enum.Enum):
    red = 1
    blue = red
    green = 2

print(Color.__dict__.keys())
print(list(Color._member_map_.keys()))
---

Python 3.5:
---
dict_keys(['__module__', '_member_names_', 'green', '_member_type_',
'blue', '_value2member_map_', '_member_map_', '__new__', 'red',
'__doc__'])
['red', 'blue', 'green']
---

Python 3.6:
---
dict_keys(['_generate_next_value_', '__module__', '__doc__',
'_member_names_', '_member_map_', '_member_type_',
'_value2member_map_', 'red', 'blue', 'green', '__new__'])
['red', 'blue', 'green']
---

Note: It seems like dir(myenum) ignores "aliases" like blue=red in my example.

Victor