File: postfix-yield.rs

package info (click to toggle)
rustc 1.87.0%2Bdfsg1-1
  • links: PTS, VCS
  • area: main
  • in suites: forky, sid
  • size: 925,564 kB
  • sloc: xml: 158,127; python: 36,039; javascript: 19,761; sh: 19,737; cpp: 18,981; ansic: 13,133; asm: 4,376; makefile: 710; perl: 29; lisp: 28; ruby: 19; sql: 11
file content (34 lines) | stat: -rw-r--r-- 912 bytes parent folder | download | duplicates (2)
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
// This demonstrates a proposed alternate or additional option of having yield in postfix position.

//@ run-pass
//@ edition: 2024

#![feature(gen_blocks, coroutines, coroutine_trait, yield_expr)]

use std::ops::{Coroutine, CoroutineState};
use std::pin::pin;

fn main() {
    // generators (i.e. yield doesn't return anything useful)
    let mut gn = gen {
        yield 1;
        2.yield;
    };

    assert_eq!(gn.next(), Some(1));
    assert_eq!(gn.next(), Some(2));
    assert_eq!(gn.next(), None);

    //coroutines (i.e. yield returns something useful)
    let mut coro = pin!(
        #[coroutine]
        |_: i32| {
            let x = 1.yield;
            (x + 2).yield;
        }
    );

    assert_eq!(coro.as_mut().resume(0), CoroutineState::Yielded(1));
    assert_eq!(coro.as_mut().resume(2), CoroutineState::Yielded(4));
    assert_eq!(coro.as_mut().resume(3), CoroutineState::Complete(()));
}