From 0d0e9fe2ffc1683758a1985ef6dedeef5ecafdbc Mon Sep 17 00:00:00 2001 From: Bas van Beek <43369155+BvB93@users.noreply.github.com> Date: Tue, 22 Sep 2020 17:55:34 +0200 Subject: [PATCH] bpo-41810: Reintroduce `types.EllipsisType`, `.NoneType` & `.NotImplementedType` (GH-22336) closes issue 41810 --- Doc/library/constants.rst | 13 +++++++----- Doc/library/types.rst | 21 +++++++++++++++++++ Doc/whatsnew/3.10.rst | 8 +++++++ Lib/test/test_types.py | 10 +++++++++ Lib/types.py | 3 +++ Misc/ACKS | 1 + .../2020-09-20-15-14-05.bpo-41810.7l8lyV.rst | 3 +++ 7 files changed, 54 insertions(+), 5 deletions(-) create mode 100644 Misc/NEWS.d/next/Library/2020-09-20-15-14-05.bpo-41810.7l8lyV.rst diff --git a/Doc/library/constants.rst b/Doc/library/constants.rst index f17e1a37875..38dd552a036 100644 --- a/Doc/library/constants.rst +++ b/Doc/library/constants.rst @@ -19,19 +19,21 @@ A small number of constants live in the built-in namespace. They are: .. data:: None - The sole value of the type ``NoneType``. ``None`` is frequently used to - represent the absence of a value, as when default arguments are not passed to a - function. Assignments to ``None`` are illegal and raise a :exc:`SyntaxError`. + An object frequently used to represent the absence of a value, as when + default arguments are not passed to a function. Assignments to ``None`` + are illegal and raise a :exc:`SyntaxError`. + ``None`` is the sole instance of the :data:`NoneType` type. .. data:: NotImplemented - Special value which should be returned by the binary special methods + A special value which should be returned by the binary special methods (e.g. :meth:`__eq__`, :meth:`__lt__`, :meth:`__add__`, :meth:`__rsub__`, etc.) to indicate that the operation is not implemented with respect to the other type; may be returned by the in-place binary special methods (e.g. :meth:`__imul__`, :meth:`__iand__`, etc.) for the same purpose. It should not be evaluated in a boolean context. + ``NotImplemented`` is the sole instance of the :data:`types.NotImplementedType` type. .. note:: @@ -59,8 +61,9 @@ A small number of constants live in the built-in namespace. They are: .. index:: single: ...; ellipsis literal .. data:: Ellipsis - The same as the ellipsis literal "``...``". Special value used mostly in conjunction + The same as the ellipsis literal "``...``". Special value used mostly in conjunction with extended slicing syntax for user-defined container data types. + ``Ellipsis`` is the sole instance of the :data:`types.EllipsisType` type. .. data:: __debug__ diff --git a/Doc/library/types.rst b/Doc/library/types.rst index 79acdf4499a..25fa750f2cc 100644 --- a/Doc/library/types.rst +++ b/Doc/library/types.rst @@ -103,6 +103,13 @@ If you instantiate any of these types, note that signatures may vary between Pyt Standard names are defined for the following types: +.. data:: NoneType + + The type of :data:`None`. + + .. versionadded:: 3.10 + + .. data:: FunctionType LambdaType @@ -186,6 +193,13 @@ Standard names are defined for the following types: .. versionadded:: 3.7 +.. data:: NotImplementedType + + The type of :data:`NotImplemented`. + + .. versionadded:: 3.10 + + .. data:: MethodDescriptorType The type of methods of some built-in data types such as :meth:`str.join`. @@ -236,6 +250,13 @@ Standard names are defined for the following types: Defaults to ``None``. Previously the attribute was optional. +.. data:: EllipsisType + + The type of :data:`Ellipsis`. + + .. versionadded:: 3.10 + + .. class:: TracebackType(tb_next, tb_frame, tb_lasti, tb_lineno) The type of traceback objects such as found in ``sys.exc_info()[2]``. diff --git a/Doc/whatsnew/3.10.rst b/Doc/whatsnew/3.10.rst index ce888fec1d8..f88281a934c 100644 --- a/Doc/whatsnew/3.10.rst +++ b/Doc/whatsnew/3.10.rst @@ -145,6 +145,14 @@ Add :data:`sys.orig_argv` attribute: the list of the original command line arguments passed to the Python executable. (Contributed by Victor Stinner in :issue:`23427`.) +types +----- + +Reintroduced the :data:`types.EllipsisType`, :data:`types.NoneType` +and :data:`types.NotImplementedType` classes, providing a new set +of types readily interpretable by type checkers. +(Contributed by Bas van Beek in :issue:`41810`.) + unittest -------- diff --git a/Lib/test/test_types.py b/Lib/test/test_types.py index f499fb9c8c5..52a59d54f04 100644 --- a/Lib/test/test_types.py +++ b/Lib/test/test_types.py @@ -713,6 +713,16 @@ class TypesTests(unittest.TestCase): assert repr(int | None) == "int | None" assert repr(int | typing.GenericAlias(list, int)) == "int | list[int]" + def test_ellipsis_type(self): + self.assertIsInstance(Ellipsis, types.EllipsisType) + + def test_notimplemented_type(self): + self.assertIsInstance(NotImplemented, types.NotImplementedType) + + def test_none_type(self): + self.assertIsInstance(None, types.NoneType) + + class MappingProxyTests(unittest.TestCase): mappingproxy = types.MappingProxyType diff --git a/Lib/types.py b/Lib/types.py index 9642e7212ca..532f4806fc0 100644 --- a/Lib/types.py +++ b/Lib/types.py @@ -296,5 +296,8 @@ def coroutine(func): GenericAlias = type(list[int]) Union = type(int | str) +EllipsisType = type(Ellipsis) +NoneType = type(None) +NotImplementedType = type(NotImplemented) __all__ = [n for n in globals() if n[:1] != '_'] diff --git a/Misc/ACKS b/Misc/ACKS index e4bd3da6b6c..7b743464c1c 100644 --- a/Misc/ACKS +++ b/Misc/ACKS @@ -134,6 +134,7 @@ Robin Becker Torsten Becker Bill Bedford Michał Bednarski +Bas van Beek Ian Beer Stefan Behnel Reimer Behrends diff --git a/Misc/NEWS.d/next/Library/2020-09-20-15-14-05.bpo-41810.7l8lyV.rst b/Misc/NEWS.d/next/Library/2020-09-20-15-14-05.bpo-41810.7l8lyV.rst new file mode 100644 index 00000000000..515aea9e36c --- /dev/null +++ b/Misc/NEWS.d/next/Library/2020-09-20-15-14-05.bpo-41810.7l8lyV.rst @@ -0,0 +1,3 @@ +:data:`types.EllipsisType`, :data:`types.NotImplementedType` and +:data:`types.NoneType` have been reintroduced, providing a new set +of types readily interpretable by static type checkers.