PEP 614: Relaxing Grammar Restrictions On Decorators

[brandtbucher]

BPO	39702
Nosy	@gvanrossum, @miss-islington, @brandtbucher, @gousaiyang, @shankarj67
PRs	bpo-39702: Relax grammar restrictions on decorators (PEP 614). #18570 bpo-39702: Update the Language Reference (PEP 614). #18802 bpo-39868: Add the documentation for Assignment Expressions (PEP 572). #18851 bpo-39702: Remove dotted_name from decorator documentation #25234 [3.9] bpo-39702: Remove dotted_name from decorator documentation (GH-25234) #25290

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = 'https://github.com/brandtbucher'
closed_at = <Date 2020-03-07.19:13:10.129>
created_at = <Date 2020-02-20.16:12:25.133>
labels = ['interpreter-core', 'type-feature', '3.9']
title = 'PEP 614: Relaxing Grammar Restrictions On Decorators'
updated_at = <Date 2021-04-08.23:04:03.217>
user = 'https://github.com/brandtbucher'

bugs.python.org fields:

activity = <Date 2021-04-08.23:04:03.217>
actor = 'miss-islington'
assignee = 'brandtbucher'
closed = True
closed_date = <Date 2020-03-07.19:13:10.129>
closer = 'brandtbucher'
components = ['Interpreter Core']
creation = <Date 2020-02-20.16:12:25.133>
creator = 'brandtbucher'
dependencies = []
files = []
hgrepos = []
issue_num = 39702
keywords = ['patch']
message_count = 8.0
messages = ['362328', '363311', '363312', '363319', '363324', '363612', '390568', '390570']
nosy_count = 5.0
nosy_names = ['gvanrossum', 'miss-islington', 'brandtbucher', 'gousaiyang', 'shankarj67']
pr_nums = ['18570', '18802', '18851', '25234', '25290']
priority = 'normal'
resolution = None
stage = 'resolved'
status = 'closed'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue39702'
versions = ['Python 3.9']

[brandtbucher]

The attached PR implements PEP-614's revised grammar for decorators, with tests. In short:

decorator: '@' dotted_name [ '(' [arglist] ')' ] NEWLINE

becomes

decorator: '@' namedexpr_test NEWLINE

I'm marking it as DO-NOT-MERGE until the PEP is accepted, but code review is still appreciated. Discussion of the PEP itself should go to the Python-Dev thread:

https://mail.python.org/archives/list/python-dev@python.org/thread/SLKFAR56RA6A533O5ZOZ7XTJ764EMB7I

[gvanrossum]

New changeset be501ca by Brandt Bucher in branch 'master':
bpo-39702: Relax grammar restrictions on decorators (PEP-614) (GH-18570)
be501ca

[gvanrossum]

I'm guessing there's some doc update that needs to happen now the code has landed.

[brandtbucher]

Agreed. I'll have something up later, hopefully.

I'll add a tiny blurb to whatsnew, as well as adding the PEP to the "See also:" note in https://docs.python.org/3.9/reference/compound_stmts.html and updating the mini-grammar there. I don't think it needs much else.

Hmmm. It looks like the page of the docs that I've linked above wasn't ever updated for the walrus. We should probably add updating this part of the docs to https://devguide.python.org/grammar/...

[gvanrossum]

Sounds good. If you feel like it you can submit a PR to the devguide, I'm sure Brett will merge it quickly...

[gvanrossum]

New changeset 8f13053 by Brandt Bucher in branch 'master':
bpo-39702: Update the Language Reference (PEP-614) (GH-18802)
8f13053