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authorGuido van Rossum <guido@dropbox.com>2015-09-09 18:21:18 (GMT)
committerGuido van Rossum <guido@dropbox.com>2015-09-09 18:21:18 (GMT)
commitac062f7935f47db37eb20b19c58304a5573eb8c3 (patch)
treefb216fe93e61f180d746d918489caca27291f084 /Doc
parent03728fac15204428ac4282710944170cb8f0b613 (diff)
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Merge typing docs cleanup diff by Zach Ware from default back into 350 branch.
Diffstat (limited to 'Doc')
-rw-r--r--Doc/library/typing.rst97
1 files changed, 50 insertions, 47 deletions
diff --git a/Doc/library/typing.rst b/Doc/library/typing.rst
index 594933c..e09b647 100644
--- a/Doc/library/typing.rst
+++ b/Doc/library/typing.rst
@@ -20,8 +20,9 @@ The function below takes and returns a string and is annotated as follows::
def greeting(name: str) -> str:
return 'Hello ' + name
-In the function `greeting`, the argument `name` is expected to by of type `str`
-and the return type `str`. Subtypes are accepted as arguments.
+In the function ``greeting``, the argument ``name`` is expected to by of type
+:class:`str` and the return type :class:`str`. Subtypes are accepted as
+arguments.
Type aliases
------------
@@ -49,8 +50,8 @@ For example::
It is possible to declare the return type of a callable without specifying
the call signature by substituting a literal ellipsis
-for the list of arguments in the type hint: `Callable[..., ReturnType]`.
-`None` as a type hint is a special case and is replaced by `type(None)`.
+for the list of arguments in the type hint: ``Callable[..., ReturnType]``.
+``None`` as a type hint is a special case and is replaced by ``type(None)``.
Generics
--------
@@ -108,11 +109,12 @@ A user-defined class can be defined as a generic class.
def log(self, message: str) -> None:
self.logger.info('{}: {}'.format(self.name, message))
-`Generic[T]` as a base class defines that the class `LoggedVar` takes a single
-type parameter `T` . This also makes `T` valid as a type within the class body.
+``Generic[T]`` as a base class defines that the class ``LoggedVar`` takes a
+single type parameter ``T`` . This also makes ``T`` valid as a type within the
+class body.
-The `Generic` base class uses a metaclass that defines `__getitem__` so that
-`LoggedVar[t]` is valid as a type::
+The :class:`Generic` base class uses a metaclass that defines
+:meth:`__getitem__` so that ``LoggedVar[t]`` is valid as a type::
from typing import Iterable
@@ -132,7 +134,7 @@ be constrained::
class StrangePair(Generic[T, S]):
...
-Each type variable argument to `Generic` must be distinct.
+Each type variable argument to :class:`Generic` must be distinct.
This is thus invalid::
from typing import TypeVar, Generic
@@ -152,9 +154,9 @@ You can use multiple inheritance with `Generic`::
class LinkedList(Sized, Generic[T]):
...
-Subclassing a generic class without specifying type parameters assumes `Any`
-for each position. In the following example, `MyIterable` is not generic but
-implicitly inherits from `Iterable[Any]`::
+Subclassing a generic class without specifying type parameters assumes
+:class:`Any` for each position. In the following example, ``MyIterable`` is
+not generic but implicitly inherits from ``Iterable[Any]``::
from typing import Iterable
@@ -162,24 +164,24 @@ implicitly inherits from `Iterable[Any]`::
Generic metaclasses are not supported.
-The `Any` type
---------------
+The :class:`Any` type
+---------------------
-A special kind of type is `Any`. Every type is a subtype of `Any`.
-This is also true for the builtin type object. However, to the static type
-checker these are completely different.
+A special kind of type is :class:`Any`. Every type is a subtype of
+:class:`Any`. This is also true for the builtin type object. However, to the
+static type checker these are completely different.
-When the type of a value is `object`, the type checker will reject almost all
-operations on it, and assigning it to a variable (or using it as a return value)
-of a more specialized type is a type error. On the other hand, when a value has
-type `Any`, the type checker will allow all operations on it, and a value of
-type `Any` can be assigned to a variable (or used as a return value) of a more
-constrained type.
+When the type of a value is :class:`object`, the type checker will reject
+almost all operations on it, and assigning it to a variable (or using it as a
+return value) of a more specialized type is a type error. On the other hand,
+when a value has type :class:`Any`, the type checker will allow all operations
+on it, and a value of type :class:`Any` can be assigned to a variable (or used
+as a return value) of a more constrained type.
Default argument values
-----------------------
-Use a literal ellipsis `...` to declare an argument as having a default value::
+Use a literal ellipsis ``...`` to declare an argument as having a default value::
from typing import AnyStr
@@ -195,9 +197,10 @@ The module defines the following classes, functions and decorators:
Special type indicating an unconstrained type.
- * Any object is an instance of `Any`.
- * Any class is a subclass of `Any`.
- * As a special case, `Any` and `object` are subclasses of each other.
+ * Any object is an instance of :class:`Any`.
+ * Any class is a subclass of :class:`Any`.
+ * As a special case, :class:`Any` and :class:`object` are subclasses of
+ each other.
.. class:: TypeVar
@@ -224,22 +227,22 @@ The module defines the following classes, functions and decorators:
return x if len(x) >= len(y) else y
The latter example's signature is essentially the overloading
- of `(str, str) -> str` and `(bytes, bytes) -> bytes`. Also note
- that if the arguments are instances of some subclass of `str`,
- the return type is still plain `str`.
+ of ``(str, str) -> str`` and ``(bytes, bytes) -> bytes``. Also note
+ that if the arguments are instances of some subclass of :class:`str`,
+ the return type is still plain :class:`str`.
- At runtime, `isinstance(x, T)` will raise `TypeError`. In general,
- `isinstance` and `issublass` should not be used with types.
+ At runtime, ``isinstance(x, T)`` will raise :exc:`TypeError`. In general,
+ :func:`isinstance` and :func:`issublass` should not be used with types.
Type variables may be marked covariant or contravariant by passing
- `covariant=True` or `contravariant=True`. See :pep:`484` for more
+ ``covariant=True`` or ``contravariant=True``. See :pep:`484` for more
details. By default type variables are invariant.
.. class:: Union
- Union type; `Union[X, Y]` means either X or Y.
+ Union type; ``Union[X, Y]`` means either X or Y.
- To define a union, use e.g. `Union[int, str]`. Details:
+ To define a union, use e.g. ``Union[int, str]``. Details:
* The arguments must be types and there must be at least one.
@@ -259,37 +262,37 @@ The module defines the following classes, functions and decorators:
Union[int, str] == Union[str, int]
- * If `Any` is present it is the sole survivor, e.g.::
+ * If :class:`Any` is present it is the sole survivor, e.g.::
Union[int, Any] == Any
* You cannot subclass or instantiate a union.
- * You cannot write `Union[X][Y]`
+ * You cannot write ``Union[X][Y]``
- * You can use `Optional[X]` as a shorthand for `Union[X, None]`.
+ * You can use ``Optional[X]`` as a shorthand for ``Union[X, None]``.
.. class:: Optional
Optional type.
- `Optional[X]` is equivalent to `Union[X, type(None)]`.
+ ``Optional[X]`` is equivalent to ``Union[X, type(None)]``.
.. class:: Tuple
- Tuple type; `Tuple[X, Y]` is the is the type of a tuple of two items
+ Tuple type; ``Tuple[X, Y]`` is the is the type of a tuple of two items
with the first item of type X and the second of type Y.
- Example: `Tuple[T1, T2]` is a tuple of two elements corresponding
- to type variables T1 and T2. `Tuple[int, float, str]` is a tuple
+ Example: ``Tuple[T1, T2]`` is a tuple of two elements corresponding
+ to type variables T1 and T2. ``Tuple[int, float, str]`` is a tuple
of an int, a float and a string.
To specify a variable-length tuple of homogeneous type,
- use literal ellipsis, e.g. `Tuple[int, ...]`.
+ use literal ellipsis, e.g. ``Tuple[int, ...]``.
.. class:: Callable
- Callable type; `Callable[[int], str]` is a function of (int) -> str.
+ Callable type; ``Callable[[int], str]`` is a function of (int) -> str.
The subscription syntax must always be used with exactly two
values: the argument list and the return type. The argument list
@@ -297,9 +300,9 @@ The module defines the following classes, functions and decorators:
There is no syntax to indicate optional or keyword arguments,
such function types are rarely used as callback types.
- `Callable[..., ReturnType]` could be used to type hint a callable
- taking any number of arguments and returning `ReturnType`.
- A plain `Callable` is equivalent to `Callable[..., Any]`.
+ ``Callable[..., ReturnType]`` could be used to type hint a callable
+ taking any number of arguments and returning ``ReturnType``.
+ A plain :class:`Callable` is equivalent to ``Callable[..., Any]``.
.. class:: Generic