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

1 files changed, 7 insertions, 6 deletions

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 @@ The abstract grammar is currently defined as follows:
 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 @@ and classes for traversing abstract syntax trees:
    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