Shmuel H. <[email protected]> added the comment:
I think it was designed to. However, it is not very usable in production for a
number of reasons:
1. It won't work with frozen instances (you'll have to call
`object.__setattr__` directly).
2. It gets very messy with more than one or two `InitVar`s which makes it very
hard to differentiate between "real"
values, `InitVar`s and the init logic:
```python
from dataclasses import dataclass, InitVar
@dataclass
class DataClass:
member0_init: InitVar[str] = None
member1_init: InitVar[list] = None
member0: int = None
member1: dict = None
def __post_init__(self, member0_init: str, member1_init: list):
if member0_init is not None and self.member0 is None:
self.member0 = int(member0_init)
if member1_init is not None and self.member1 is None:
self.member1 = dict(member1_init)
```
That code should be equivalent to:
```python
from dataclasses import dataclass
from typing import Union
@dataclass
class DataClass:
member0: int
member1: dict
def __init__(self, member0: Union[int, str], member1: Union[dict, list]):
if isinstance(member0, str):
member0 = int(member0)
if isinstance(member1, list):
member1 = dict(member1)
self.__default_init__(member0=member0, member1=member1)
```
Which is much closer to regular python code to someone new for dataclasses.
I would be happy to hear if you have a better solution; I just think it is
pretty simple and straight-forward.
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<https://bugs.python.org/issue38444>
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