return type same as class gives NameError.
dn
PythonList at DancesWithMice.info
Sun Oct 22 12:54:50 EDT 2023
On 23/10/2023 04.50, Antoon Pardon via Python-list wrote:
> I have the following small module:
>
> =-=-=-=-=-=-=-=-=-=-=-= 8< =-=-=-=-=-=-=-=-=-=-=-=-=
>
> from typing import NamedTuple, TypeAlias, Union
> from collections.abc import Sequence
>
> PNT: TypeAlias = tuple[float, float]
>
> class Pnt (NamedTuple):
> x: float
> y: float
>
> def __add__(self, other: PNT) -> Pnt:
> return Pnt(self[0] + other[0], self[1] + other[1])
>
> =-=-=-=-=-=-=-=-=-=-=-= >8 =-=-=-=-=-=-=-=-=-=-=-=-=
>
> But when I import this, I get the following diagnostic:
>
> Traceback (most recent call last):
> File "<stdin>", line 1, in <module>
> File "/home/sisc/projecten/iudex/problem.py", line 10, in <module>
> class Pnt (NamedTuple):
> File "/home/sisc/projecten/iudex/problem.py", line 14, in Pnt
> def __add__(self, other: PNT) -> Pnt:
> ^^^
> NameError: name 'Pnt' is not defined. Did you mean: 'PNT'?
>
>
> Can someone explain what I am doing wrong?
What happens when the advice is followed?
Not sure why declare type-alias and then don't use it, but if insist on
using class-name will be making a "forward-reference" (because class has
not yet been fully defined) - see
https://mypy.readthedocs.io/en/stable/cheat_sheet_py3.html#forward-references
--
Regards,
=dn
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