Add Rc<T> and Arc<T> sources

[InfiniteCoder01]

No description provided.

[jeertmans]

Nice @InfiniteCoder01! Running the checks, can you update the code to make all tests pas?

[InfiniteCoder01]

@jeertmans, sorry for not reading feature list properly. Now I've fixed it (I don't think Rc and Arc appear in nostd environment)

[jeertmans]

Thanks @InfiniteCoder01! Could you please add one or two tests, and a docstring on top of each class, to show very basic examples?

[InfiniteCoder01]

I don't see any tests for implementation of Source trait for str and [u8]. Could you give me an example?
As for docs, I didn't add any structs/types, just implemented some traits.

[jeertmans]

@InfiniteCoder01 Did you check https://github.com/maciejhirsz/logos/blob/master/logos/src/source.rs?

It contains implementation of Source for both str and [u8].

[InfiniteCoder01]

Those are implementations, but there are no docs, nor tests for them (docs only for Source trait). But there is a module-level doc comment where I've added new sources.

[jeertmans]

True, but that's not because there is no documentation at the moment that it isn't worth adding some :-)

[InfiniteCoder01]

In rust, you can't add docs to impl Trait and it's methods. But I'll add some tests then

[InfiniteCoder01]

Can't really add tests until #341

[jeertmans]

oh yeah, you've got a good point!

Looking at your code, I actually wonder if it just makes sense to rather implement Source for AsRef<T: impl Source>?

[ikrivosheev]

@InfiniteCoder01 hello! It will be cool to add Box.

[marcospb19]

I implemented this for Rc and Arc using a single impl block:

//! * `Source` - implemented by default for `&str`, `&[u8]` and wrapper types, used by the `Lexer`.

...

#[cfg(feature = "std")]
impl<T> Source for T
where
    T: Deref,
    <T as Deref>::Target: Source,
{
    type Slice<'a> = <T::Target as Source>::Slice<'a>
        where T: 'a;

    fn len(&self) -> usize {
        self.deref().len()
    }

    fn read<'a, Chunk>(&'a self, offset: usize) -> Option<Chunk>
    where
        Chunk: self::Chunk<'a>,
    {
        self.deref().read(offset)
    }
    
    ...
}

@InfiniteCoder01 hello! It will be cool to add Box.

Box also implements Deref, so the impl above covers it too.

[marcospb19]

I tried using AsRef instead of Deref but couldn't.

impl<T, Inner> Source for T
where
    T: AsRef<Inner>,
    Inner: Source,
{

error[E0207]: the type parameter `Inner` is not constrained by the impl trait, self type, or predicates

Deref uses associated types and AsRef doesn't, I think that makes it impossible to implement this for AsRef.

[jeertmans]

Makes sense, thank you! @InfiniteCoder01 Could you please update your branch with respect to the master and resolve conflicts? So I can merge it :)

[InfiniteCoder01]

Sorry for closing the PR, I'm still bad at git stuff. Should work now, tested with cargo test and cargo hack check --feature-powerset --no-dev-deps

[jeertmans]

No issue, thanks for replying so quickly @InfiniteCoder01! Running CI, it seems that you should run cargo fmt on your code :-)

[jeertmans]

Thank you for your contribution!