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https://github.com/PrettyWood/future-typing
Backport for type hinting generics in standard collections and union types as X | Y
https://github.com/PrettyWood/future-typing
Last synced: about 1 month ago
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Backport for type hinting generics in standard collections and union types as X | Y
- Host: GitHub
- URL: https://github.com/PrettyWood/future-typing
- Owner: PrettyWood
- License: mit
- Created: 2021-01-25T22:09:32.000Z (almost 4 years ago)
- Default Branch: main
- Last Pushed: 2021-05-14T12:04:33.000Z (over 3 years ago)
- Last Synced: 2024-04-29T11:31:59.921Z (8 months ago)
- Language: Python
- Size: 44.9 KB
- Stars: 16
- Watchers: 1
- Forks: 1
- Open Issues: 5
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
- awesome-python-typing - future-typing - Backport for type hinting generics in standard collections and union types as `X | Y`. (Backports and improvements)
README
# future-typing
[](https://github.com/PrettyWood/future-typing/actions)
[](https://codecov.io/gh/PrettyWood/future-typing)
[](https://pypi.python.org/pypi/future-typing)
[](https://github.com/PrettyWood/future-typing)
[](https://github.com/PrettyWood/future-typing/blob/master/LICENSE)
Use generic type hints and new union syntax `|` with python 3.6+
If you just want to use new annotations for type checkers like `mypy`, then do not use this library
and simply add `from __future__ import annotations`.
But if you want to use those annotations at runtime, then you may be at the right place!
This library exposes:
- `transform_annotation`, which will transform `list[str|int|float]` into
* `typing.List[typing.Union[str, int, float]]` for python 3.6 to 3.8
* `list[typing.Union[str, int, float]]` for python 3.9 (since generic types are natively supported)
- a custom source code encoding `future_typing` that you can use to trigger the transformation at
interpretation time
- a CLI to see the transformed source
## Installation
``` bash
pip install future_typing
```
## Codec
Just add this custom source code encoding at the top of your file
```
# -*- coding: future_typing -*-
```
and then use `|` and `list[str]`, `dict[str, int]`, ... as if you were using `python 3.10`
```python
# -*- coding: future_typing -*-
from typing import Literal
class C:
@staticmethod
def g(t: tuple[int, ...]) -> tuple[int, ...]:
return t
def f(a: list[str | int] | dict[str, str], b: Literal['pika'] | None = None) -> type[C]:
x: set[str | int] = set(a)
y: frozenset[str] = frozenset(['y1', 'y2'])
t: tuple[int, ...] = (1, 2)
print(f'it works! a: {a!r}, b: {b!r}')
return C
f(['a', 'b', 1], 'pika')
```
```console
$ python3.8 pika.py
it works! a: ['a', 'b'], b: 'pika'
$ mypy pika.py
Success: no issues found in 1 source file
```
## CLI
```console
$ future_typing pika.py
import typing as typing___
from typing import Literal
class C :
@staticmethod
def g (t :typing___.Tuple [int ,...])->typing___.Tuple [int ,...]:
return t
def f (a :typing___.Union [typing___.List [typing___.Union [str ,int ]],typing___.Dict [str ,str ]],b :typing___.Union [Literal ['pika'],None ]=None )->typing___.Type [C ]:
x :typing___.Set [typing___.Union [str ,int ]]=set (a )
y :typing___.FrozenSet [str ]=frozenset (['y1','y2'])
t :typing___.Tuple [int ,...]=(1 ,2 )
print (f'it works! a: {a!r}, b: {b!r}')
return C
f (['a','b',1 ],'pika')
```