xref: /openbmc/linux/rust/macros/concat_idents.rs (revision 7ae9fb1b7ecbb5d85d07857943f677fd1a559b18)
1*60f18c22SBjörn Roy Baron // SPDX-License-Identifier: GPL-2.0
2*60f18c22SBjörn Roy Baron 
3*60f18c22SBjörn Roy Baron use proc_macro::{token_stream, Ident, TokenStream, TokenTree};
4*60f18c22SBjörn Roy Baron 
5*60f18c22SBjörn Roy Baron use crate::helpers::expect_punct;
6*60f18c22SBjörn Roy Baron 
expect_ident(it: &mut token_stream::IntoIter) -> Ident7*60f18c22SBjörn Roy Baron fn expect_ident(it: &mut token_stream::IntoIter) -> Ident {
8*60f18c22SBjörn Roy Baron     if let Some(TokenTree::Ident(ident)) = it.next() {
9*60f18c22SBjörn Roy Baron         ident
10*60f18c22SBjörn Roy Baron     } else {
11*60f18c22SBjörn Roy Baron         panic!("Expected Ident")
12*60f18c22SBjörn Roy Baron     }
13*60f18c22SBjörn Roy Baron }
14*60f18c22SBjörn Roy Baron 
concat_idents(ts: TokenStream) -> TokenStream15*60f18c22SBjörn Roy Baron pub(crate) fn concat_idents(ts: TokenStream) -> TokenStream {
16*60f18c22SBjörn Roy Baron     let mut it = ts.into_iter();
17*60f18c22SBjörn Roy Baron     let a = expect_ident(&mut it);
18*60f18c22SBjörn Roy Baron     assert_eq!(expect_punct(&mut it), ',');
19*60f18c22SBjörn Roy Baron     let b = expect_ident(&mut it);
20*60f18c22SBjörn Roy Baron     assert!(it.next().is_none(), "only two idents can be concatenated");
21*60f18c22SBjörn Roy Baron     let res = Ident::new(&format!("{a}{b}"), b.span());
22*60f18c22SBjörn Roy Baron     TokenStream::from_iter([TokenTree::Ident(res)])
23*60f18c22SBjörn Roy Baron }
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