Re: [PATCH 7/7] rust: init: add support for arbitrary paths in init macros

[Benno Lossin]

On 25.06.23 23:01, Gary Guo wrote:
> On Sat, 24 Jun 2023 09:25:39 +0000
> Benno Lossin <benno.lossin@xxxxxxxxx> wrote:
> 
>> Previously only `ident` and generic types were supported in the
>> `{try_}{pin_}init!` macros. This patch allows arbitrary path fragments,
>> so for example `Foo::Bar` but also very complex paths such as
>> `<Foo as Baz>::Bar::<0, i32>`.
>>
>> Internally this is accomplished by using `path` fragments. Due to some
>> peculiar declarative macro limitations, we have to "forget" certain
>> additional parsing information in the token trees. This is achieved by
>> the new `retokenize` proc macro. It does not modify the input, but just
>> strips this information. For example, if a declarative macro takes
>> `$t:path` as its input, it cannot sensibly propagate this to a macro that
>> takes `$($p:tt)*` as its input, since the `$t` token will only be
>> considered one `tt` token for the second macro. If we first pipe the
>> tokens through `retokenize`, then it parses as expected.
> 
> I think this "retokenize" macro could also be functionally replaced by
> `paste`. Would you mind to apply my paste patch (referenced in a
> previous email) and see if it works?

I tried your patch and it seems to work. I also executed all of the test
in the userspace library and they passed.
The `paste!` code also looks good to me. One thing that I thought was this:
do we want to accept `paste!( [<= foo bar>])`? Because the `<` token has
spacing `Joint`, maybe add a check for that? No idea if that would be a problem.

-- 
Cheers,
Benno

> 
> Best,
> Gary
>