PEP Idea: Better return type annotation syntax
With the recent submission of [PEP 677][1], I was reminded of an idea I had with function annotation syntax since the very beginning: why not let me write: ```python def f() -> tuple[int, str]: return 42, 'foo' ``` as: ```python def f() -> (int, str): return 42, 'foo' ``` Is there any inherent reason for this, other than that it isn't an actual "type"? I think it looks much cleaner, and if there isn't any drawbacks to adding this syntax, I'd love to work on bringing this to life. [1]: https://www.python.org/dev/peps/pep-0677/
On Thu, Jan 6, 2022 at 10:44 PM Tushar Sadhwani < tushar.sadhwani000@gmail.com> wrote:
With the recent submission of [PEP 677][1], I was reminded of an idea I had with function annotation syntax since the very beginning:
why not let me write:
```python def f() -> tuple[int, str]: return 42, 'foo' ```
as:
```python def f() -> (int, str): return 42, 'foo' ```
Is there any inherent reason for this, other than that it isn't an actual "type"?
I like this too. A practical issue is that list[(a, b)] and list[a, b] look the same to the compiler, but they would mean very different things. It's not obvious how to fix this in a backward-compatible way.
I think it looks much cleaner, and if there isn't any drawbacks to adding this syntax, I'd love to work on bringing this to life.
[1]: https://www.python.org/dev/peps/pep-0677/ _______________________________________________ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-leave@python.org https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/NLZOBG... Code of Conduct: http://python.org/psf/codeofconduct/
Jelle Zijlstra wrote:
I like this too. A practical issue is that list[(a, b)] and list[a, b] look the same to the compiler, but they would mean very different things. It's not obvious how to fix this in a backward-compatible way. I think it looks much cleaner, and if there isn't any drawbacks to adding this syntax, I'd love to work on bringing this to life.
Restricting it to only the top level of a return type annotation should do the trick! Such that: def f() -> (X, Y, Z): ... is interpreted as tuple[X, Y, Z], but: def f(x: (X, Y, Z)) -> None: ... def f() -> Union[int, (X, Y, Z)]: ... def f() -> list[(X, Y, Z)]: ... Are not considered as tuple[...]
participants (2)
-
Jelle Zijlstra -
Tushar Sadhwani