bpo-35766: Change format for feature_version to (major, minor) (GH-13992)
(A single int is still allowed, but undocumented.)
https://bugs.python.org/issue35766
diff --git a/Doc/library/ast.rst b/Doc/library/ast.rst
index 1884bea..1e71838 100644
--- a/Doc/library/ast.rst
+++ b/Doc/library/ast.rst
@@ -126,7 +126,7 @@
Apart from the node classes, the :mod:`ast` module defines these utility functions
and classes for traversing abstract syntax trees:
-.. function:: parse(source, filename='<unknown>', mode='exec', *, type_comments=False, feature_version=-1)
+.. function:: parse(source, filename='<unknown>', mode='exec', *, type_comments=False, feature_version=None)
Parse the source into an AST node. Equivalent to ``compile(source,
filename, mode, ast.PyCF_ONLY_AST)``.
@@ -145,11 +145,12 @@
modified to correspond to :pep:`484` "signature type comments",
e.g. ``(str, int) -> List[str]``.
- Also, setting ``feature_version`` to the minor version of an
- earlier Python 3 version will attempt to parse using that version's
- grammar. For example, setting ``feature_version=4`` will allow
- the use of ``async`` and ``await`` as variable names. The lowest
- supported value is 4; the highest is ``sys.version_info[1]``.
+ Also, setting ``feature_version`` to a tuple ``(major, minor)``
+ will attempt to parse using that Python version's grammar.
+ Currently ``major`` must equal to ``3``. For example, setting
+ ``feature_version=(3, 4)`` will allow the use of ``async`` and
+ ``await`` as variable names. The lowest supported version is
+ ``(3, 4)``; the highest is ``sys.version_info[0:2]``.
.. warning::
It is possible to crash the Python interpreter with a