cpython/Doc/reference
Matthew Rahtz 7d3497f617
gh-115528: Update language reference for PEP 646 (#121181)
To recap: the objective is to make starred expressions valid in `subscription`,
which is used for generics: `Generic[...]`, `list[...]`, etc.

What _is_ gramatically valid in such contexts? Seemingly any of the following.
(At least, none of the following throw `SyntaxError` in a 3.12.3 REPL.)

    Generic[x]
    Generic[*x]
    Generic[*x, y]
    Generic[y, *x]
    Generic[x := 1]
    Generic[x := 1, y := 2]

So introducting

    flexible_expression: expression | assignment_expression | starred_item

end then switching `subscription` to use `flexible_expression` sorts that.

But then we need to field `yield` - for which any of the following are
apparently valid:

    yield x
    yield x,
    yield x, y
    yield *x,
    yield *x, *y

Introducing a separate `yield_list` is the simplest way I've been figure out to
do this - separating out the special case of `starred_item ,`.



Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com>
2024-09-26 12:35:17 -07:00
..
compound_stmts.rst gh-115528: Update language reference for PEP 646 (#121181) 2024-09-26 12:35:17 -07:00
datamodel.rst gh-101100: Make __subclasses__ doctest stable (#124577) 2024-09-26 06:26:03 +00:00
executionmodel.rst gh-101100: Add a table of class attributes to the "Custom classes" section of the data model docs (#124480) 2024-09-25 19:29:58 +00:00
expressions.rst gh-115528: Update language reference for PEP 646 (#121181) 2024-09-26 12:35:17 -07:00
grammar.rst Docs: Add label to grammar spec for linking from PEPs (#113235) 2023-12-17 12:23:14 -07:00
import.rst import: permit __name__ for use in __name__ = "__main__": (#124381) 2024-09-25 10:39:14 -07:00
index.rst Merge from 3.2: remove unneeded "Release" and "Date" markers from index pages. 2012-10-28 11:10:24 -07:00
introduction.rst GH-103484: Fix permanently redirects reported by linkcheck (GH-124144) 2024-09-17 02:53:38 +00:00
lexical_analysis.rst closes gh-124016: update Unicode to 16.0.0 (#124017) 2024-09-13 07:47:04 -07:00
simple_stmts.rst gh-119180: Documentation for PEP 649 and 749 (#122235) 2024-09-11 07:49:59 -07:00
toplevel_components.rst GH-97950: Use new-style index directive ('builtin') (#104164) 2023-05-06 06:54:08 +03:00