macros/
concat_idents.rs

1// SPDX-License-Identifier: GPL-2.0
2
3use proc_macro::{token_stream, Ident, TokenStream, TokenTree};
4
5use crate::helpers::expect_punct;
6
7fn expect_ident(it: &mut token_stream::IntoIter) -> Ident {
8    if let Some(TokenTree::Ident(ident)) = it.next() {
9        ident
10    } else {
11        panic!("Expected Ident")
12    }
13}
14
15pub(crate) fn concat_idents(ts: TokenStream) -> TokenStream {
16    let mut it = ts.into_iter();
17    let a = expect_ident(&mut it);
18    assert_eq!(expect_punct(&mut it), ',');
19    let b = expect_ident(&mut it);
20    assert!(it.next().is_none(), "only two idents can be concatenated");
21    let res = Ident::new(&format!("{a}{b}"), b.span());
22    TokenStream::from_iter([TokenTree::Ident(res)])
23}