https://github.com/python/cpython/commit/46cf4fc8a5646ca35f7d1ac06d2ef33eb9e... commit: 46cf4fc8a5646ca35f7d1ac06d2ef33eb9efca1d branch: 3.7 author: Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com> committer: GitHub <noreply@github.com> date: 2020-02-13T16:03:12-08:00 summary: bpo-39545: Document changes in the support of await in f-strings. (GH-18456) https://bugs.python.org/issue39545 (cherry picked from commit f632736023502816f2e6bd714d1b48c81aa2ccc1) Co-authored-by: Serhiy Storchaka <storchaka@gmail.com> files: M Doc/reference/lexical_analysis.rst M Doc/whatsnew/3.7.rst diff --git a/Doc/reference/lexical_analysis.rst b/Doc/reference/lexical_analysis.rst index 7b90f3b31c37b..9f51f41edd501 100644 --- a/Doc/reference/lexical_analysis.rst +++ b/Doc/reference/lexical_analysis.rst @@ -683,6 +683,11 @@ can contain line breaks (e.g. in triple-quoted strings), but they cannot contain comments. Each expression is evaluated in the context where the formatted string literal appears, in order from left to right. +.. versionchanged:: 3.7 + Prior to Python 3.7, an :keyword:`await` expression and comprehensions + containing an :keyword:`async for` clause were illegal in the expressions + in formatted string literals due to a problem with the implementation. + If a conversion is specified, the result of evaluating the expression is converted before formatting. Conversion ``'!s'`` calls :func:`str` on the result, ``'!r'`` calls :func:`repr`, and ``'!a'`` calls :func:`ascii`. diff --git a/Doc/whatsnew/3.7.rst b/Doc/whatsnew/3.7.rst index c7e3230db29e6..9644a4f31a957 100644 --- a/Doc/whatsnew/3.7.rst +++ b/Doc/whatsnew/3.7.rst @@ -493,6 +493,11 @@ of this mode. Other Language Changes ====================== +* An :keyword:`await` expression and comprehensions containing an + :keyword:`async for` clause were illegal in the expressions in + :ref:`formatted string literals <f-strings>` due to a problem with the + implementation. In Python 3.7 this restriction was lifted. + * More than 255 arguments can now be passed to a function, and a function can now have more than 255 parameters. (Contributed by Serhiy Storchaka in :issue:`12844` and :issue:`18896`.)