How to allow a class attribute to be accessible from the module global context in Python?

Question

I defined an enum class and would like to be able to use its attributes without need to access it through class name. I mean:

class MyEnum:
    ONE = 1
    TWO = 2
    ...

if MyEnum.ONE == 1:
    "Typic use"
if TWO == 2:
    "My desire"

Is there a way to do this?

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In my specific context, I'm calculating points externality of a window through Cohen–Sutherland algorithm, so I have the following code:

class Externality:
    INSIDE = 0
    LEFT = 1
    RIGTH = 2
    BELLOW = 4
    ABOVE = 8

# And at some point:
((x, y), externality) = actual

if not Externality.INSIDE in externality:
    del cohen_sutherland_list[0]

So, the needed of express Enum's name to access its items make the if statement (and the whole code) a little more verbose and redundant.

Answer 1

First things first: inherit from Enum.

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Like everything in Python, all you need to do is assign the names:

from enum import Enum

class MyEnum(Enum):
    ONE = 1
    TWO = 2

ONE = MyEnum.ONE
TWO = MyEnum.TWO

That can get annoying fast, so a helper function would be nice:

def export_enum(enum_cls, env):
    for member in enum_cls:
        env[member.name] = member

and in use:

>>> export_enum(MyEnum, globals())
>>> TWO
<MyEnum.TWO: 2>

If you use aenum¹ the export() function is already available, and can be used as a decorator:

from aenum import Enum, export

@export(globals())
class MyEnum(Enum):
    ONE = 1
    TWO = 2

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¹ Disclosure: I am the author of the Python stdlib Enum, the enum34 backport, and the Advanced Enumeration (aenum) library.