Model (for validators, ORM, form library) by using dataclass

dataclass_model.py

from dataclasses import dataclass, field as dc_field


# Library


def field(default, verbose_name="", help_text=""):
    return dc_field(
        default=default,
        metadata={
            'verbose_name': verbose_name,
            'help_text': help_text,
        }
    )


# mypy doen't recognize aliases for dataclass
# So we can't provide nice @model class decorator intead of dataclass
# https://github.com/python/mypy/issues/5383

class Model:
    def print_fields(self):
        for name, field in self.__dataclass_fields__.items():
            print(field.metadata['verbose_name'], getattr(self, name))


# User

@dataclass
class User(Model):
    name: str = field("john", "名前", "User name")


user = User(name="hiroki")
user.print_fields()  # 名前 hiroki