Dataclasses and property decorator

Question

I\'ve been reading up on Python 3.7\'s dataclass as an alternative to namedtuples (what I typically use when having to group data in a structure). I was wondering if datacla

Answer 1

Some wrapping could be good:

# Copyright 2019 Xu Siyuan
# 
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
# 
# http://www.apache.org/licenses/LICENSE-2.0
# 
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License. 

from dataclasses import dataclass, field

MISSING = object()
__all__ = ['property_field', 'property_dataclass']


class property_field:
    def __init__(self, fget=None, fset=None, fdel=None, doc=None, **kwargs):
        self.field = field(**kwargs)
        self.property = property(fget, fset, fdel, doc)

    def getter(self, fget):
        self.property = self.property.getter(fget)
        return self

    def setter(self, fset):
        self.property = self.property.setter(fset)
        return self

    def deleter(self, fdel):
        self.property = self.property.deleter(fdel)
        return self


def property_dataclass(cls=MISSING, / , **kwargs):
    if cls is MISSING:
        return lambda cls: property_dataclass(cls, **kwargs)
    remembers = {}
    for k in dir(cls):
        if isinstance(getattr(cls, k), property_field):
            remembers[k] = getattr(cls, k).property
            setattr(cls, k, getattr(cls, k).field)
    result = dataclass(**kwargs)(cls)
    for k, p in remembers.items():
        setattr(result, k, p)
    return result

You can use it like this:

@property_dataclass
class B:
    x: int = property_field(default_factory=int)

    @x.getter
    def x(self):
        return self._x

    @x.setter
    def x(self, value):
        self._x = value