[Python-ideas] Re: Make dataclass aware that it might be used with Enum

July 18, 2022

      On 7/7/22 18:22, Steve Jorgensen wrote:
...
After some playing around, I figured out a pattern that works without any changes to the
implementations of `dataclass` or `Enum`, and I like this because it keeps the 2 kinds of
concern separate. Maybe I'll try submitting an MR to add an example like this to the
documentation for `Enum`.
In [1]: from dataclasses import dataclass
In [2]: from enum import Enum
In [3]: @dataclass(frozen=True)
    ...: class CreatureDataMixin:
    ...:     size: str
    ...:     legs: int
    ...:
In [4]: class Creature(CreatureDataMixin, Enum):
    ...:     BEETLE = ('small', 6)
    ...:     DOG = ('medium', 4)
    ...:
In [5]: Creature.DOG
Out[5]: Creature(size='medium', legs=4)
I'm impressed that you found a way to make it work.  Be aware that some of the bug-fixing in 3.11 has changed the 
resulting repr() -- the above now looks like:

<Creature.DOG: CreatureDataMixin(size='medium', legs=4)>

It would be possible to have Enum check to see if the data type is a dataclass, and then see if the repr is set to be 
automatically created:
...
...
...
CreatureDataMixin.__dataclass_params__
_DataclassParams(init=True,repr=True,eq=True,order=False,unsafe_hash=False,frozen=True)
I'll have to look into that.

It does seem like a lot of extra work, or at least no less work, than just writing an `__init__` in the enum class directly.

--
~Ethan~

[Python-ideas] Re: Make dataclass aware that it might be used with Enum

Ethan Furman