[Python-checkins] Improve code examples in `typing.rst` (#105346)
AlexWaygood
webhook-mailer at python.org
Wed Jun 7 02:47:20 EDT 2023
https://github.com/python/cpython/commit/81c81328a4fa13fead6f8cc9053a1a32a62a0279
commit: 81c81328a4fa13fead6f8cc9053a1a32a62a0279
branch: main
author: Alex Waygood <Alex.Waygood at Gmail.com>
committer: AlexWaygood <Alex.Waygood at Gmail.com>
date: 2023-06-07T07:47:11+01:00
summary:
Improve code examples in `typing.rst` (#105346)
files:
M Doc/library/typing.rst
diff --git a/Doc/library/typing.rst b/Doc/library/typing.rst
index 503bef137e31..f75fb48f09f2 100644
--- a/Doc/library/typing.rst
+++ b/Doc/library/typing.rst
@@ -2,6 +2,11 @@
:mod:`typing` --- Support for type hints
========================================
+.. testsetup:: *
+
+ import typing
+ from typing import *
+
.. module:: typing
:synopsis: Support for type hints (see :pep:`484`).
@@ -261,19 +266,22 @@ Callable
Frameworks expecting callback functions of specific signatures might be
type hinted using ``Callable[[Arg1Type, Arg2Type], ReturnType]``.
-For example::
+For example:
+
+.. testcode::
from collections.abc import Callable
def feeder(get_next_item: Callable[[], str]) -> None:
- # Body
+ ... # Body
def async_query(on_success: Callable[[int], None],
on_error: Callable[[int, Exception], None]) -> None:
- # Body
+ ... # Body
async def on_update(value: str) -> None:
- # Body
+ ... # Body
+
callback: Callable[[str], Awaitable[None]] = on_update
It is possible to declare the return type of a callable without specifying
@@ -431,11 +439,14 @@ In this case ``MyDict`` has a single parameter, ``T``.
Using a generic class without specifying type parameters assumes
:data:`Any` for each position. In the following example, ``MyIterable`` is
-not generic but implicitly inherits from ``Iterable[Any]``::
+not generic but implicitly inherits from ``Iterable[Any]``:
+
+.. testcode::
from collections.abc import Iterable
class MyIterable(Iterable): # Same as Iterable[Any]
+ ...
User-defined generic type aliases are also supported. Examples::
@@ -701,9 +712,11 @@ These can be used as types in annotations and do not support ``[]``.
A string created by composing ``LiteralString``-typed objects
is also acceptable as a ``LiteralString``.
- Example::
+ Example:
+
+ .. testcode::
- def run_query(sql: LiteralString) -> ...
+ def run_query(sql: LiteralString) -> None:
...
def caller(arbitrary_string: str, literal_string: LiteralString) -> None:
@@ -1596,9 +1609,9 @@ without the dedicated syntax, as documented below.
def __abs__(self) -> "Array[*Shape]": ...
def get_shape(self) -> tuple[*Shape]: ...
- Type variable tuples can be happily combined with normal type variables::
+ Type variable tuples can be happily combined with normal type variables:
- DType = TypeVar('DType')
+ .. testcode::
class Array[DType, *Shape]: # This is fine
pass
@@ -1606,6 +1619,9 @@ without the dedicated syntax, as documented below.
class Array2[*Shape, DType]: # This would also be fine
pass
+ class Height: ...
+ class Width: ...
+
float_array_1d: Array[float, Height] = Array() # Totally fine
int_array_2d: Array[int, Height, Width] = Array() # Yup, fine too
@@ -1759,7 +1775,9 @@ without the dedicated syntax, as documented below.
The type of type aliases created through the :keyword:`type` statement.
- Example::
+ Example:
+
+ .. doctest::
>>> type Alias = int
>>> type(Alias)
@@ -1769,7 +1787,9 @@ without the dedicated syntax, as documented below.
.. attribute:: __name__
- The name of the type alias::
+ The name of the type alias:
+
+ .. doctest::
>>> type Alias = int
>>> Alias.__name__
@@ -2147,7 +2167,11 @@ These are not used in annotations. They are building blocks for declaring types.
group: list[T]
To create a generic ``TypedDict`` that is compatible with Python 3.11
- or lower, inherit from :class:`Generic` explicitly::
+ or lower, inherit from :class:`Generic` explicitly:
+
+ .. testcode::
+
+ T = TypeVar("T")
class Group(TypedDict, Generic[T]):
key: T
@@ -2160,7 +2184,9 @@ These are not used in annotations. They are building blocks for declaring types.
.. attribute:: __total__
``Point2D.__total__`` gives the value of the ``total`` argument.
- Example::
+ Example:
+
+ .. doctest::
>>> from typing import TypedDict
>>> class Point2D(TypedDict): pass
@@ -2190,7 +2216,9 @@ These are not used in annotations. They are building blocks for declaring types.
non-required keys in the same ``TypedDict`` . This is done by declaring a
``TypedDict`` with one value for the ``total`` argument and then
inheriting from it in another ``TypedDict`` with a different value for
- ``total``::
+ ``total``:
+
+ .. doctest::
>>> class Point2D(TypedDict, total=False):
... x: int
@@ -2844,12 +2872,12 @@ Functions and decorators
decorated object performs runtime "magic" that
transforms a class, giving it :func:`dataclasses.dataclass`-like behaviors.
- Example usage with a decorator function::
+ Example usage with a decorator function:
- T = TypeVar("T")
+ .. testcode::
@dataclass_transform()
- def create_model(cls: type[T]) -> type[T]:
+ def create_model[T](cls: type[T]) -> type[T]:
...
return cls
@@ -2953,7 +2981,9 @@ Functions and decorators
runtime but should be ignored by a type checker. At runtime, calling
a ``@overload``-decorated function directly will raise
:exc:`NotImplementedError`. An example of overload that gives a more
- precise type than can be expressed using a union or a type variable::
+ precise type than can be expressed using a union or a type variable:
+
+ .. testcode::
@overload
def process(response: None) -> None:
@@ -2965,7 +2995,7 @@ Functions and decorators
def process(response: bytes) -> str:
...
def process(response):
- <actual implementation>
+ ... # actual implementation goes here
See :pep:`484` for more details and comparison with other typing semantics.
@@ -3057,10 +3087,13 @@ Functions and decorators
This helps prevent bugs that may occur when a base class is changed without
an equivalent change to a child class.
- For example::
+ For example:
+
+ .. testcode::
class Base:
- def log_status(self)
+ def log_status(self) -> None:
+ ...
class Sub(Base):
@override
@@ -3119,14 +3152,16 @@ Introspection helpers
The function recursively replaces all ``Annotated[T, ...]`` with ``T``,
unless ``include_extras`` is set to ``True`` (see :class:`Annotated` for
- more information). For example::
+ more information). For example:
+
+ .. testcode::
class Student(NamedTuple):
name: Annotated[str, 'some marker']
- get_type_hints(Student) == {'name': str}
- get_type_hints(Student, include_extras=False) == {'name': str}
- get_type_hints(Student, include_extras=True) == {
+ assert get_type_hints(Student) == {'name': str}
+ assert get_type_hints(Student, include_extras=False) == {'name': str}
+ assert get_type_hints(Student, include_extras=True) == {
'name': Annotated[str, 'some marker']
}
@@ -3153,7 +3188,9 @@ Introspection helpers
If ``X`` is an instance of :class:`ParamSpecArgs` or :class:`ParamSpecKwargs`,
return the underlying :class:`ParamSpec`.
Return ``None`` for unsupported objects.
- Examples::
+ Examples:
+
+ .. testcode::
assert get_origin(str) is None
assert get_origin(Dict[str, int]) is dict
@@ -3172,7 +3209,9 @@ Introspection helpers
generic type, the order of ``(Y, Z, ...)`` may be different from the order
of the original arguments ``[Y, Z, ...]`` due to type caching.
Return ``()`` for unsupported objects.
- Examples::
+ Examples:
+
+ .. testcode::
assert get_args(int) == ()
assert get_args(Dict[int, str]) == (int, str)
@@ -3184,14 +3223,20 @@ Introspection helpers
Check if a type is a :class:`TypedDict`.
- For example::
+ For example:
+
+ .. testcode::
class Film(TypedDict):
title: str
year: int
- is_typeddict(Film) # => True
- is_typeddict(list | str) # => False
+ assert is_typeddict(Film)
+ assert not is_typeddict(list | str)
+
+ # TypedDict is a factory for creating typed dicts,
+ # not a typed dict itself
+ assert not is_typeddict(TypedDict)
.. versionadded:: 3.10
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