2017-06-24 13:26:04 -05:00
|
|
|
// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
|
|
|
|
// file at the top-level directory of this distribution and at
|
|
|
|
// http://rust-lang.org/COPYRIGHT.
|
|
|
|
//
|
|
|
|
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
|
|
|
|
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
|
|
|
|
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
|
|
|
|
// option. This file may not be copied, modified, or distributed
|
|
|
|
// except according to those terms.
|
|
|
|
|
|
|
|
macro_rules! enum_number {
|
|
|
|
($name:ident { $($variant:ident = $value:expr, )* }) => {
|
|
|
|
enum $name {
|
|
|
|
$($variant = $value,)*
|
|
|
|
}
|
|
|
|
|
|
|
|
fn foo(value: i32) -> Option<$name> {
|
|
|
|
match value {
|
|
|
|
$( $value => Some($name::$variant), )* // PatKind::Lit
|
|
|
|
$( $value ... 42 => Some($name::$variant), )* // PatKind::Range
|
|
|
|
_ => None
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
enum_number!(Change {
|
|
|
|
Pos = 1,
|
|
|
|
Neg = -1,
|
|
|
|
Arith = 1 + 1, //~ ERROR arbitrary expressions aren't allowed in patterns
|
2017-10-25 08:02:26 -05:00
|
|
|
//~^ ERROR only char and numeric types are allowed in range patterns
|
2017-06-24 13:26:04 -05:00
|
|
|
});
|
|
|
|
|
|
|
|
fn main() {}
|
|
|
|
|