This is an old feature request that appears from time to time. After a year of experimenting with various introspection capabilities in `typing_inspect` on PyPI, I propose to add these two most commonly used functions: `get_origin()` and `get_args()`. These are essentially thin public wrappers around private APIs: `__origin__` and `__args__`.
As discussed in the issue and on the typing tracker, exposing some public helpers instead of `__origin__` and `__args__` directly will give us more flexibility if we will decide to update the internal representation, while still maintaining backwards compatibility.
The implementation is very simple an is essentially a copy from `typing_inspect` with one exception: `ClassVar` was special-cased in `typing_inspect`, but I think this special-casing doesn't really help and only makes things more complicated.
I tried to get rid of the `_ProtocolMeta`, but unfortunately it didn'y work. My idea to return a generic alias from `@runtime_checkable` made runtime protocols unpickleable. I am not sure what is worse (a custom metaclass or having some classes unpickleable), so I decided to stick with the status quo (since there were no complains so far). So essentially this is a copy of the implementation in `typing_extensions` with two modifications:
* Rename `@runtime` to `@runtime_checkable` (plus corresponding updates).
* Allow protocols that extend `collections.abc.Iterable` etc.
The implementation is straightforward, it just mimics `ClassVar` (since the latter is also a name/access qualifier, not really a type). Also it is essentially copied from `typing_extensions`.
In order to support typing checks calling hex(), oct() and bin() on user-defined classes, a SupportIndex protocol is required. The ability to check these at runtime would be good to add for completeness sake. This is pretty much just a copy of SupportsInt with the names tweaked.
This also fixespython/typing#512
This also fixespython/typing#511
As was discussed in both issues, some typing forms deserve to be treated
as immutable by copy and pickle modules, so that:
* copy(X) is X
* deepcopy(X) is X
* loads(dumps(X)) is X # pickled by reference
This PR adds such behaviour to:
* Type variables
* Special forms like Union, Any, ClassVar
* Unsubscripted generic aliases to containers like List, Mapping, Iterable
This not only resolves inconsistencies mentioned in the issues, but also
improves backwards compatibility with previous versions of Python
(including 3.6).
Note that this requires some dances with __module__ for type variables
(similar to NamedTuple) because the class TypeVar itself is define in typing,
while type variables should get module where they were defined.
https://bugs.python.org/issue32873
This makes the default behavior (without specifying `globalns` manually) more
predictable for users, finds the right globalns automatically.
Implementation for classes assumes has a `__module__` attribute and that module
is present in `sys.modules`. It does this recursively for all bases in the
MRO. For modules, the implementation just uses their `__dict__` directly.
This is backwards compatible, will just raise fewer exceptions in naive user
code.
Originally implemented and reviewed at https://github.com/python/typing/pull/470.
This PR contains two updates to typing module:
- Support ContextManager on all versions (original PR by Jelle Zijlstra).
- Add generic AsyncContextManager.
(Upstream is https://github.com/python/typing)
- Add TYPE_CHECKING (false at runtime, true in type checkers) (upstream #230).
- Avoid error on Union[xml.etree.cElementTree.Element, str] (upstream #229).
- Repr of Tuple[()] should be 'Tuple[()]' (upstream #231).
- Add NewType() (upstream #189).
This has no semantic impact as the class is guarded with a hasattr()
check; this is being done to keep typing.py in sync between Python 3.5
and 3.6 as requested by Guido.
This syncs to rev 7b43ada77821d23e55e3a4b35f6055a59b9e1ad7 there.
Summary:
- Add typing.DefaultDict (as a generic variant of collections.defaultdict).
- Use collections.Reversible if it exists (only relevant for Python 3.6).
- Revamped generic class behavior to conform to updated PEP 484.
- Improve speed of Generic.__new__.
- Make sure __init__ is called for new Generic instances. Fix issue #26391.
- Refactor async support to be compatible with 3.2, 3.3, 3.4.
- Remove 'io' and 're' from __all__ (they still exist, just not
included by "import *"). Fix issue #26234.
- Change @overload -- you can now use it outside stubs (you still
cannot call the decorated function though).
There area bunch of TODOs here, but the biggest (not mentioned in the
file) is that I'm going to take out __instancecheck__ and
__subclasscheck__. However my personal schedule is such that I
probably won't have time for these before Larry tags beta 1. But I
will try -- this commit is mostly to make sure that typing.py doesn't
completely miss the train.
PS. I'm tracking issues at https://github.com/ambv/typehinting/issues.
Ivan Levkivskyi
Anthony Sottile
Paul Dagnelie
Raymond Hettinger
Ismo Toijala
Srinivas Thatiparthy (శ్రీనివాస్ తాటిపర్తి)
Noah Wood
Tim McNamara
João D. Ferreira
Serhiy Storchaka
Nina Zakharenko
Ville Skyttä
aetracht
Łukasz Langa
Guido van Rossum
Raymond Hettinger
Guido van Rossum
Brett Cannon