repr.py

class Repr:
    """Repr method generator

    Automatically parse object init-based definition.
    To include extra fields, list them in `__repr_include__`.

    >>> class User(Repr):
    ...     __repr_include__ = ['uri']
    ...
    ...     def __init__(self, uid: int, uname: str, referral: int = None):
    ...         self.id = uid
    ...         self.uname = uname
    ...         self.referral = referral
    ...
    ...     @property
    ...     def uri(self):
    ...         return f'https://example.com/users/{self.id}'

    >>> User(2, uname='Bob', referral=1)
    User(2, uname='Bob', referral=1)  # uri='https://example.com/users/2'

    """

    __repr_include__ = []

    def __new__(cls, *args, **kwargs):
        _ = super().__new__(cls)
        _._source_data_ = (args, kwargs)

        return _

    def __repr__(self):
        """Auto generated repr.

        Return code of object init-definition, based on name
        and data, provided while initialization.

        Extra fields from `__repr_include__` will be joined
        as comment for initialization code. If field not found,
        this key will be just skipped.

        """

        arguments = ', '.join(map(repr, self._source_data_[0]))
        keyword_arguments = ', '.join(f'{k}={repr(v)}' for k, v in self._source_data_[1].items())
        include = ', '.join(f'{k}={repr(getattr(self, k))}'
                            for k in self.__repr_include__
                            if k in self.__dir__())

        if keyword_arguments:
            keyword_arguments = ', ' + keyword_arguments

        result = f'{self.__class__.__name__}({arguments + keyword_arguments})'

        if include:
            result += '  # ' + include

        return result