Function dataclass

Lib/dataclasses.py:1415–1443

Add dunder methods based on the fields defined in the class. Examines PEP 526 __annotations__ to determine fields. If init is true, an __init__() method is added to the class. If repr is true, a __repr__() method is added. If order is true, rich comparison dunder methods are added.

(cls=None, /, *, init=True, repr=True, eq=True, order=False,
              unsafe_hash=False, frozen=False, match_args=True,
              kw_only=False, slots=False, weakref_slot=False)

def dataclass(cls=None, /, *, init=True, repr=True, eq=True, order=False,
              unsafe_hash=False, frozen=False, match_args=True,
              kw_only=False, slots=False, weakref_slot=False):
    """Add dunder methods based on the fields defined in the class.

    Examines PEP 526 __annotations__ to determine fields.

    If init is true, an __init__() method is added to the class. If repr
    is true, a __repr__() method is added. If order is true, rich
    comparison dunder methods are added. If unsafe_hash is true, a
    __hash__() method is added. If frozen is true, fields may not be
    assigned to after instance creation. If match_args is true, the
    __match_args__ tuple is added. If kw_only is true, then by default
    all fields are keyword-only. If slots is true, a new class with a
    __slots__ attribute is returned.
    """

    def wrap(cls):
        return _process_class(cls, init, repr, eq, order, unsafe_hash,
                              frozen, match_args, kw_only, slots,
                              weakref_slot)

    # See if we're being called as @dataclass or @dataclass().
    if cls is None:
        # We're called with parens.
        return wrap

    # We're called as @dataclass without parens.
    return wrap(cls)


def fields(class_or_instance):