1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
|
// run-pass
// Regression test for issue #25436: permit token-trees to be followed
// by sequences, enabling more general parsing.
use self::Join::*;
#[derive(Debug)]
#[allow(unused_tuple_struct_fields)]
enum Join<A,B> {
Keep(A,B),
Skip(A,B),
}
macro_rules! parse_list {
( < $a:expr; > $($b:tt)* ) => { Keep(parse_item!($a),parse_list!($($b)*)) };
( $a:tt $($b:tt)* ) => { Skip(parse_item!($a), parse_list!($($b)*)) };
( ) => { () };
}
macro_rules! parse_item {
( $x:expr ) => { $x }
}
fn main() {
let list = parse_list!(<1;> 2 <3;> 4);
assert_eq!("Keep(1, Skip(2, Keep(3, Skip(4, ()))))",
format!("{:?}", list));
}
|
