File: macro-pat.rs

package info (click to toggle)
rustc 1.85.0%2Bdfsg3-1
  • links: PTS, VCS
  • area: main
  • in suites: experimental, sid, trixie
  • size: 893,396 kB
  • sloc: xml: 158,127; python: 35,830; javascript: 19,497; cpp: 19,002; sh: 17,245; ansic: 13,127; asm: 4,376; makefile: 1,051; perl: 29; lisp: 29; ruby: 19; sql: 11
file content (41 lines) | stat: -rw-r--r-- 724 bytes parent folder | download | duplicates (5)
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
29
30
31
32
33
34
35
36
37
38
39
40
41
//@ run-pass
//@ edition:2021

use Foo::*;

#[allow(dead_code)]
#[derive(Eq, PartialEq, Debug)]
enum Foo {
    A(u64),
    B(u64),
    C,
    D,
}

macro_rules! foo {
    ($orpat:pat, $val:expr) => {
        match $val {
            x @ ($orpat) => x, // leading vert would not be allowed in $orpat
            _ => B(0xDEADBEEFu64),
        }
    };
}

macro_rules! bar {
    ($orpat:pat, $val:expr) => {
        match $val {
            $orpat => 42, // leading vert allowed here
            _ => 0xDEADBEEFu64,
        }
    };
}

fn main() {
    // Test or-pattern.
    let y = foo!(A(_)|B(_), A(32));
    assert_eq!(y, A(32));

    // Leading vert in or-pattern.
    let y = bar!(|C| D, C);
    assert_eq!(y, 42u64);
}