https://github.com/python/cpython/commit/f632736023502816f2e6bd714d1b48c81aa... commit: f632736023502816f2e6bd714d1b48c81aa2ccc1 branch: master author: Serhiy Storchaka <storchaka@gmail.com> committer: GitHub <noreply@github.com> date: 2020-02-13T15:57:35-08:00 summary: bpo-39545: Document changes in the support of await in f-strings. (GH-18456) https://bugs.python.org/issue39545 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 c0e13b53698e6..3d4b03e6bd459 100644 --- a/Doc/reference/lexical_analysis.rst +++ b/Doc/reference/lexical_analysis.rst @@ -685,6 +685,11 @@ 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 04cfa57e1446f..59b96621bdd4b 100644 --- a/Doc/whatsnew/3.7.rst +++ b/Doc/whatsnew/3.7.rst @@ -493,6 +493,11 @@ description. 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`.)