Path: csiph.com!fu-berlin.de!uni-berlin.de!not-for-mail
From: Hynek Schlawack <hs@ox.cx>
Newsgroups: comp.lang.python.announce
Subject: attrs 17.3.0 released!
Date: Wed, 8 Nov 2017 19:20:58 +0100
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Hi everyone,

I=E2=80=99m very excited to announce the 17.3.0 release of attrs =
<http://www.attrs.org/>, the package that will make you love writing =
classes again!

A lot has happened under the hood but the main feature we=E2=80=99d like =
to point out is first-class support for types including PEP 526-style =
class variable annotations:

```pycon
>>> @attr.s
... class C:
...     x =3D attr.ib(type=3Dint)
...     y: int =3D attr.ib()
>>> attr.fields(C).x.type
<class 'int'>
>>> attr.fields(C).y.type
<class 'int'>
```

And if you=E2=80=99re OK with annotating *all* attributes, you can drop =
the `attr.ib()` completely with the new `auto_attribs` option.  Anything =
that is assigned to the attributes and isn=E2=80=99t an `attr.ib` is =
used as a default value:

```pycon
>>> import typing
>>> @attr.s(auto_attribs=3DTrue)
... class AutoC:
...     cls_var: typing.ClassVar[int] =3D 5  # this one is ignored
...     l: typing.List[int] =3D attr.Factory(list)
...     x: int =3D 1
...     bar: typing.Any =3D None
>>> AutoC()
AutoC(l=3D[], x=3D1, bar=3DNone)
```

Please note:

- This feature works with Python 3.6 and later only.
- The type information is currently *not* used by attrs itself, but it =
allows you to write advanced validators and serializers.

Check out the changelog for all changes: =
<http://www.attrs.org/en/stable/changelog.html>
Get it from PyPI: <https://pypi.org/project/attrs/>

For the attrs team,
Hynek Schlawack=