https://github.com/python/cpython/commit/ee141f027715658e1e69b5f3b6f7e8c6c2f95b2c commit: ee141f027715658e1e69b5f3b6f7e8c6c2f95b2c branch: 3.14 author: Miss Islington (bot) <31488909+miss-isling...@users.noreply.github.com> committer: gpshead <g...@krypto.org> date: 2025-06-15T00:38:19Z summary:
[3.14] gh-135171: Update documentation for the generator expression (GH-135351) (#135524) gh-135171: Update documentation for the generator expression (GH-135351) * gh-135171: Update documentation for the generator expression Document that the iterator for the leftmost "for" clause is created immediately. * Update Doc/reference/expressions.rst --------- (cherry picked from commit 8979d3afe376c67931665070a79f6939ebcd940b) Co-authored-by: Serhiy Storchaka <storch...@gmail.com> Co-authored-by: Brian Skinn <brian.sk...@gmail.com> files: A Misc/NEWS.d/next/Documentation/2025-06-10-17-02-06.gh-issue-135171.quHvts.rst M Doc/reference/expressions.rst diff --git a/Doc/reference/expressions.rst b/Doc/reference/expressions.rst index 2a550b504ca765..3d3bf1d9840eef 100644 --- a/Doc/reference/expressions.rst +++ b/Doc/reference/expressions.rst @@ -406,8 +406,9 @@ brackets or curly braces. Variables used in the generator expression are evaluated lazily when the :meth:`~generator.__next__` method is called for the generator object (in the same fashion as normal generators). However, the iterable expression in the -leftmost :keyword:`!for` clause is immediately evaluated, so that an error -produced by it will be emitted at the point where the generator expression +leftmost :keyword:`!for` clause is immediately evaluated, and the +:term:`iterator` is immediately created for that iterable, so that an error +produced while creating the iterator will be emitted at the point where the generator expression is defined, rather than at the point where the first value is retrieved. Subsequent :keyword:`!for` clauses and any filter condition in the leftmost :keyword:`!for` clause cannot be evaluated in the enclosing scope as they may diff --git a/Misc/NEWS.d/next/Documentation/2025-06-10-17-02-06.gh-issue-135171.quHvts.rst b/Misc/NEWS.d/next/Documentation/2025-06-10-17-02-06.gh-issue-135171.quHvts.rst new file mode 100644 index 00000000000000..129ff74189bc64 --- /dev/null +++ b/Misc/NEWS.d/next/Documentation/2025-06-10-17-02-06.gh-issue-135171.quHvts.rst @@ -0,0 +1,2 @@ +Document that the :term:`iterator` for the leftmost :keyword:`!for` clause +in the generator expression is created immediately. _______________________________________________ Python-checkins mailing list -- python-checkins@python.org To unsubscribe send an email to python-checkins-le...@python.org https://mail.python.org/mailman3//lists/python-checkins.python.org Member address: arch...@mail-archive.com
