feat: add parse_attr_into

[cathaysia]

add parse_attr_into macro, making the following code possible:

#[derive(Debug, Default, FromMeta)]
#[darling(default)]
pub struct Attr {
    pub default: bool,
}

#[proc_macro_attribute]
pub fn api(attr: TokenStream, input: TokenStream) -> TokenStream {
    let _attr = parse_attr_into!(attr as Attr);
    input
}

[TedDriggs]

I made some changes here but for some reason those aren't showing up on the PR.

[cathaysia]

I agree with your changes. Now that the changes have been written to the branch of this repository, this PR should be closed. If you think it's okay, please close this PR

[cathaysia]

I see that the branch has not been merged yet. Do you have any questions?

[TedDriggs]

No - I’m traveling for work right now, so haven’t had time to tidy this up.

[TedDriggs]

I'm going to have to revert this, since it appears to be incorrect in the macro definition. I don't think it should be ident, and I'm not sure why it passed tests with this in place.

[cathaysia]

ok

[TedDriggs]

I think it probably wants a tt or something else in this position; do you know what syn's equivalent macro takes?

[TedDriggs]

If we can revert and fix in rapid succession that'd be great, because I do like the concept here.

[TedDriggs]

Yep, it's a tt (source)

[TedDriggs]

Here's the call that's failing and I don't think should fail:

let x: NegatableIdentList = parse_meta!(inner(example::flag, my_feature));

The impl of NegatableIdentList shouldn't matter, as the error I'm getting is...

error: no rules expected the token `(`
  --> examples/negative_flag.rs:46:38
   |
46 |     let attr_demo = parse_meta!(inner(example::flag, my_feature));
   |                                      ^ no rules expected this token in macro call
   |
note: while trying to match meta-variable `$attr:tt`
  --> /Users/teddriggs/repos/darling/core/src/lib.rs:63:6
   |
63 |     ($attr:tt) => {
   |      ^^^^^^^^

[cathaysia]

may it should be ($id:ident $params:tt). Judging from the source code of quote, this piece needs to be parsed recursively.

[TedDriggs]

Okay - I'm not sure how we reopen a PR; can you take a fork from my branch for this and submit a new PR with the updates off that?

[cathaysia]

emm, ok. I will do it tomorrow

---

From: Ted Driggs @.> Sent: Monday, March 11, 2024 11:02:21 PM To: TedDriggs/darling @.> Cc: DragonBillow @.>; Author @.> Subject: Re: [TedDriggs/darling] feat: add parse_attr_into (PR #277)

Okay - I'm not sure how we reopen a PR; can you take a fork from my branch for this and submit a new PR with the updates off that?

― Reply to this email directly, view it on GitHubhttps://github.com/TedDriggs/darling/pull/277#issuecomment-1988652149, or unsubscribehttps://github.com/notifications/unsubscribe-auth/AKBJ6AIJYYBW3VCP6WBDIV3YXXIQ3AVCNFSM6AAAAABD7K3FGOVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMYTSOBYGY2TEMJUHE. You are receiving this because you authored the thread.Message ID: @.***>