[Python-checkins] gh-95913: Copyedit, link & format Typing Features section in 3.11 What's New (GH-96097)
miss-islington
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Mon Sep 19 09:51:19 EDT 2022
https://github.com/python/cpython/commit/bda451b7944952d4066cc7c1891567187b6d70dc
commit: bda451b7944952d4066cc7c1891567187b6d70dc
branch: 3.11
author: Miss Islington (bot) <31488909+miss-islington at users.noreply.github.com>
committer: miss-islington <31488909+miss-islington at users.noreply.github.com>
date: 2022-09-19T06:51:08-07:00
summary:
gh-95913: Copyedit, link & format Typing Features section in 3.11 What's New (GH-96097)
Co-authored-by: Ezio Melotti <ezio.melotti at gmail.com>
Co-authored-by: Alex Waygood <Alex.Waygood at Gmail.com>
(cherry picked from commit 558768ff22e47582ae95ad7c3f8955407934916e)
Co-authored-by: C.A.M. Gerlach <CAM.Gerlach at Gerlach.CAM>
files:
M Doc/whatsnew/3.11.rst
diff --git a/Doc/whatsnew/3.11.rst b/Doc/whatsnew/3.11.rst
index b57e1427909..a84bfde5c48 100644
--- a/Doc/whatsnew/3.11.rst
+++ b/Doc/whatsnew/3.11.rst
@@ -208,6 +208,7 @@ PEP written by Zac Hatfield-Dodds.)
.. _new-feat-related-type-hints-311:
+.. _whatsnew311-typing-features:
New Features Related to Type Hints
==================================
@@ -215,15 +216,20 @@ New Features Related to Type Hints
This section covers major changes affecting :pep:`484` type hints and
the :mod:`typing` module.
+
+.. _whatsnew311-pep646:
+
PEP 646: Variadic generics
--------------------------
-:pep:`484` introduced :data:`~typing.TypeVar`, enabling creation
-of generics parameterised with a single type. :pep:`646` introduces
+:pep:`484` previously introduced :data:`~typing.TypeVar`, enabling creation
+of generics parameterised with a single type. :pep:`646` adds
:data:`~typing.TypeVarTuple`, enabling parameterisation
with an *arbitrary* number of types. In other words,
a :data:`~typing.TypeVarTuple` is a *variadic* type variable,
-enabling *variadic* generics. This enables a wide variety of use cases.
+enabling *variadic* generics.
+
+This enables a wide variety of use cases.
In particular, it allows the type of array-like structures
in numerical computing libraries such as NumPy and TensorFlow to be
parameterised with the array *shape*. Static type checkers will now
@@ -235,26 +241,30 @@ See :pep:`646` for more details.
Serhiy Storchaka and Jelle Zijlstra. PEP written by Mark Mendoza, Matthew
Rahtz, Pradeep Kumar Srinivasan, and Vincent Siles.)
+
+.. _whatsnew311-pep655:
+
PEP 655: Marking individual ``TypedDict`` items as required or not-required
---------------------------------------------------------------------------
:data:`~typing.Required` and :data:`~typing.NotRequired` provide a
straightforward way to mark whether individual items in a
-:data:`~typing.TypedDict` must be present. Previously this was only possible
+:class:`~typing.TypedDict` must be present. Previously, this was only possible
using inheritance.
-Fields are still required by default, unless the ``total=False``
-parameter is set.
-For example, the following specifies a dictionary with one required and
-one not-required key::
+All fields are still required by default,
+unless the *total* parameter is set to ``False``,
+in which case all fields are still not-required by default.
+For example, the following specifies a :class:`!TypedDict`
+with one required and one not-required key::
class Movie(TypedDict):
title: str
year: NotRequired[int]
- m1: Movie = {"title": "Black Panther", "year": 2018} # ok
- m2: Movie = {"title": "Star Wars"} # ok (year is not required)
- m3: Movie = {"year": 2022} # error (missing required field title)
+ m1: Movie = {"title": "Black Panther", "year": 2018} # OK
+ m2: Movie = {"title": "Star Wars"} # OK (year is not required)
+ m3: Movie = {"year": 2022} # ERROR (missing required field title)
The following definition is equivalent::
@@ -267,15 +277,20 @@ See :pep:`655` for more details.
(Contributed by David Foster and Jelle Zijlstra in :issue:`47087`. PEP
written by David Foster.)
+
+.. _whatsnew311-pep673:
+
PEP 673: ``Self`` type
----------------------
The new :data:`~typing.Self` annotation provides a simple and intuitive
way to annotate methods that return an instance of their class. This
-behaves the same as the :data:`~typing.TypeVar`-based approach specified
-in :pep:`484` but is more concise and easier to follow.
+behaves the same as the :class:`~typing.TypeVar`-based approach
+:pep:`specified in PEP 484 <484#annotating-instance-and-class-methods>`,
+but is more concise and easier to follow.
-Common use cases include alternative constructors provided as classmethods
+Common use cases include alternative constructors provided as
+:func:`classmethod <classmethod>`\s,
and :meth:`~object.__enter__` methods that return ``self``::
class MyLock:
@@ -300,6 +315,9 @@ See :pep:`673` for more details.
(Contributed by James Hilton-Balfe in :issue:`46534`. PEP written by
Pradeep Kumar Srinivasan and James Hilton-Balfe.)
+
+.. _whatsnew311-pep675:
+
PEP 675: Arbitrary literal string type
--------------------------------------
@@ -334,14 +352,17 @@ See :pep:`675` for more details.
(Contributed by Jelle Zijlstra in :issue:`47088`. PEP written by Pradeep
Kumar Srinivasan and Graham Bleaney.)
+
+.. _whatsnew311-pep681:
+
PEP 681: Data Class Transforms
------------------------------
:data:`~typing.dataclass_transform` may be used to
decorate a class, metaclass, or a function that is itself a decorator.
The presence of ``@dataclass_transform()`` tells a static type checker that the
-decorated object performs runtime "magic" that
-transforms a class, giving it :func:`dataclasses.dataclass`-like behaviors.
+decorated object performs runtime "magic" that transforms a class,
+giving it :func:`dataclass <dataclasses.dataclass>`-like behaviors.
For example::
@@ -353,26 +374,32 @@ For example::
cls.__ne__ = ...
return cls
- # The create_model decorator can now be used to create new model
- # classes, like this:
+ # The create_model decorator can now be used to create new model classes:
@create_model
class CustomerModel:
id: int
name: str
- c = CustomerModel(id=327, name="John Smith")
+ c = CustomerModel(id=327, name="Eric Idle")
See :pep:`681` for more details.
(Contributed by Jelle Zijlstra in :gh:`91860`. PEP written by
Erik De Bonte and Eric Traut.)
-PEP 563 May Not Be the Future
+
+.. _whatsnew311-pep563-deferred:
+
+PEP 563 may not be the future
-----------------------------
-* :pep:`563` Postponed Evaluation of Annotations, ``__future__.annotations``
- that was planned for this release has been indefinitely postponed.
- See `this message <https://mail.python.org/archives/list/python-dev@python.org/message/VIZEBX5EYMSYIJNDBF6DMUMZOCWHARSO/>`_ for more information.
+:pep:`563` Postponed Evaluation of Annotations
+(the ``from __future__ import annotations`` :ref:`future statement <future>`)
+that was originally planned for release in Python 3.10
+has been put on hold indefinitely.
+See `this message from the Steering Council <https://mail.python.org/archives/list/python-dev@python.org/message/VIZEBX5EYMSYIJNDBF6DMUMZOCWHARSO/>`__
+for more information.
+
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