Indeed, there needs to be a way to get back and forth from the little typing
language to Python and back.
That’s why I suggested the t-string format: in analogy to f-strings you could
use {expression} constructs in there that would be evaluated in the normal
Python environment (and syntax).
For the sake of argument lets assume for now that the little language uses
- a : b to be equivalent to Mapping[a, b]
- [a] to be Sequence[a]
- (a, b) being Tuple[a, b]
- (a, b) -> c being Callable,
- *a being Iterable[a]
- ?a being Optional[a]
Then your example would become something like
T = TypeVar(’T’)
Data = t’str : [(int, T)]’
Factory = t’(int, *str) -> ?[Data(T)]’
And note that I’m making up the syntax as I’m typing. Maybe it’s much better to
use keywords (like optional, iterable) in stead of symbols).
--
Jack Jansen, <jack.jan...@cwi.nl>, http://www.cwi.nl/~jack
If I can't dance I don't want to be part of your revolution -- Emma Goldman
> On 8 Jan 2022, at 11:32, Serhiy Storchaka <storch...@gmail.com> wrote:
>
> 08.01.22 01:59, jack.jan...@cwi.nl пише:
>>> If I can make a wild suggestion: why not create a little language for
>>> type specifications?
>
> We need a way to define aliases. For example, write:
>
> Data = Mapping[str, Sequence[Tuple[int, T]]]
> Factory = Callable[[int, Iterable[str]], Optional[list[Data[T]]]]
>
> def get_foo_factory(type: str, id: int) -> Factory[Foo]: ...
>
> instead of
>
> def get_foo_factory(type: str, id: int) -> Callable[[int,
> Iterable[str]], Optional[list[Mapping[str, Sequence[Tuple[int,
> Foo]]]]]]: ...
>
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