attrs 21.3: New Namespace and match_args

Overview

attrs 21.3, released on December 28, 2021, introduces import attrs as a new namespace and adds match_args support for pattern matching.

Main Features

attrs namespace

The new import attrs namespace with attrs.define replaces the old @attr.s, offering a more modern API.

import attrs

@attrs.define
class Point:
    x: float
    y: float

p = Point(1.0, 2.0)
print(p)  # Point(x=1.0, y=2.0)

match_args

__match_args__ support lets attrs classes work with Python 3.10+ pattern matching.

import attrs

@attrs.define
class Command:
    action: str
    target: str

cmd = Command('move', 'north')

match cmd:
    case Command('move', direction):
        print(f'Moving {direction}')
    case Command('look', _):
        print('Looking around')

Sources

• attrs Changelog