This tool uses undataclass.py to demonstrate what dataclasses really do for us. Python's dataclass decorator gives us __init__, __repr__, and __eq__ methods and (depending on what options we send) much more as well!
Paste your dataclass below to see what happens.
Or play around:
remove frozen=True
,
add kw_only=True
,
add = field(repr=False, default=0)
to the last line,
or try something complex.
Curious how this works? Read how and why I used match-case while writing this and the full walk through of how this works.
class Point:
__slots__ = ('x', 'y', 'z')
__match_args__ = ('x', 'y', 'z')
def __init__(self, x: float, y: float, z: float) -> None:
object.__setattr__(self, 'x', x)
object.__setattr__(self, 'y', y)
object.__setattr__(self, 'z', z)
def __repr__(self):
cls = type(self).__name__
return f'{cls}(x={self.x!r}, y={self.y!r}, z={self.z!r})'
def __eq__(self, other):
if not isinstance(other, Point):
return NotImplemented
return (self.x, self.y, self.z) == (other.x, other.y, other.z)
def __hash__(self):
return hash((self.x, self.y, self.z))
def __setattr__(self, name, value):
raise AttributeError(f"Can't set attribute {name!r}")
def __delattr__(self, name):
raise AttributeError(f"Can't delete attribute {name!r}")
def __getstate__(self):
return (self.x, self.y, self.z)
def __setstate__(self, state):
fields = ('x', 'y', 'z')
for field, value in zip(fields, state):
object.__setattr__(self, field, value)