On Sun, Apr 10, 2022 at 2:39 AM Daniel Pope <lord.ma...@gmail.com> wrote:
> On Fri, 8 Apr 2022, 17:44 Guido van Rossum, <gu...@python.org> wrote:
>
>> The interesting idea here seems to make "lazy imports" easier to
>> implement by making them explicit in the code. So far, most lazy import
>> frameworks for Python have done hacks with `__getattribute__` overrides.
>>
>
> The value is more than ease of implementation. Having syntax for import
> expressions makes them statically analysable, which is needed for type
> checkers and IDE autocompletion.
>
> But I also see value in being able to type out code that uses modules not
> yet imported without breaking my flow to add an import statement. I don't
> yet trust IDEs to do this because I've been bitten by them doing so
> incorrectly in the past.
>
> The key questions to me are
>> - What should the notation be?
>>
>
> I would like to bid again for (import package.module) as an expression.
> Instead of doing the import and assigning package to a variable package it
> would evaluate to the module object package.module.
>
That is an extremely subtle shift for what `import x.y` does compared to
`(import x.y)`. That requires a context switch of not only seeing `import`
in an expression context, but that the statement also acts differently in
terms of what is returned by the equivalent statement. I really don't to
try and teach that distinction to a newcomer. And I don't think the
ergonomics are great enough to warrant the context switch.
Plus you can do this today with imortlib.import_module(). Unless you're
suggesting the name also be bound in the scope it's run in? In which case
that's `(abc := importlib.import_module("collections.abc")).Mapping`.
-Brett
>
> The `as` form is not needed because no name is assigned and the `from`
> form isn't as valuable because you can just use attribute access afterwards.
>
> It isn't terse but it does make use of the import keyword and is thus
> instantly recognisable. It is even syntax highlighted correctly by much
> existing software. If we're using the import keyword then I think it has to
> look like this.
>
> But I concede that it isn't particularly elegant to type hint things with
>
> (import collections.abc).Mapping
>
> ...but not so inelegant that I couldn't see myself using it for a few
> one-off imports per module.
>
> A quirk is that it means there's a big difference between the statements
>
> import foo
>
> and
>
> (import foo)
>
> because one assigns a variable. I don't mind that; I don't think it is too
> ambiguous to a reader.
>
>
>
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