2021-09-28 12:03:12 -05:00
|
|
|
extern crate proc_macro;
|
2024-09-24 04:58:04 -05:00
|
|
|
use proc_macro::{Delimiter, Group, Ident, Span, TokenStream, TokenTree, token_stream};
|
2021-09-28 12:03:12 -05:00
|
|
|
|
|
|
|
fn read_ident(iter: &mut token_stream::IntoIter) -> Ident {
|
|
|
|
match iter.next() {
|
|
|
|
Some(TokenTree::Ident(i)) => i,
|
|
|
|
_ => panic!("expected ident"),
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
#[proc_macro_derive(DeriveBadSpan)]
|
|
|
|
pub fn derive_bad_span(input: TokenStream) -> TokenStream {
|
|
|
|
let mut input = input.into_iter();
|
|
|
|
assert_eq!(read_ident(&mut input).to_string(), "struct");
|
|
|
|
let ident = read_ident(&mut input);
|
|
|
|
let mut tys = match input.next() {
|
|
|
|
Some(TokenTree::Group(g)) if g.delimiter() == Delimiter::Parenthesis => g.stream().into_iter(),
|
|
|
|
_ => panic!(),
|
|
|
|
};
|
|
|
|
let field1 = read_ident(&mut tys);
|
|
|
|
tys.next();
|
|
|
|
let field2 = read_ident(&mut tys);
|
|
|
|
|
|
|
|
<TokenStream as FromIterator<TokenTree>>::from_iter(
|
|
|
|
[
|
|
|
|
Ident::new("impl", Span::call_site()).into(),
|
|
|
|
ident.into(),
|
|
|
|
Group::new(
|
|
|
|
Delimiter::Brace,
|
|
|
|
<TokenStream as FromIterator<TokenTree>>::from_iter(
|
|
|
|
[
|
|
|
|
Ident::new("fn", Span::call_site()).into(),
|
|
|
|
Ident::new("_foo", Span::call_site()).into(),
|
|
|
|
Group::new(Delimiter::Parenthesis, TokenStream::new()).into(),
|
|
|
|
Group::new(
|
|
|
|
Delimiter::Brace,
|
|
|
|
<TokenStream as FromIterator<TokenTree>>::from_iter(
|
|
|
|
[
|
|
|
|
Ident::new("if", field1.span()).into(),
|
|
|
|
Ident::new("true", field1.span()).into(),
|
|
|
|
{
|
|
|
|
let mut group = Group::new(Delimiter::Brace, TokenStream::new());
|
|
|
|
group.set_span(field1.span());
|
|
|
|
group.into()
|
|
|
|
},
|
|
|
|
Ident::new("if", field2.span()).into(),
|
|
|
|
Ident::new("true", field2.span()).into(),
|
|
|
|
{
|
|
|
|
let mut group = Group::new(Delimiter::Brace, TokenStream::new());
|
|
|
|
group.set_span(field2.span());
|
|
|
|
group.into()
|
|
|
|
},
|
|
|
|
]
|
|
|
|
.iter()
|
|
|
|
.cloned(),
|
|
|
|
),
|
|
|
|
)
|
|
|
|
.into(),
|
|
|
|
]
|
|
|
|
.iter()
|
|
|
|
.cloned(),
|
|
|
|
),
|
|
|
|
)
|
|
|
|
.into(),
|
|
|
|
]
|
|
|
|
.iter()
|
|
|
|
.cloned(),
|
|
|
|
)
|
|
|
|
}
|