prime_generator.rs

// date: 2020-01-10
// update: 2024-04-01
// license: GPLv3 https://www.gnu.org/licenses/gpl-3.0.txt
// author: nanpuyue <[email protected]> https://blog.nanpuyue.com

#![feature(coroutines)]
#![feature(coroutine_trait)]

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

fn prime_generator() -> impl Coroutine<Yield = u16, Return = Vec<u16>> {
    || {
        yield 2;
        yield 3;
        let mut n = 3u16;
        let mut l = vec![n];
        while let Some(x) = n.checked_add(2) {
            n = x;
            let mut y = true;
            for &i in &l {
                let (q, r) = (n / i, n % i);
                if i > q {
                    break;
                } else if r == 0 {
                    y = false;
                    break;
                }
            }
            if y {
                l.push(n);
                yield n;
            }
        }
        l
    }
}

fn main() {
    let mut coroutine = prime_generator();
    let mut i = 0;
    print!("\n   0: ");
    loop {
        match Pin::new(&mut coroutine).resume(()) {
            CoroutineState::Yielded(x) => {
                print!("{x:5} ");
                if i % 10 == 9 {
                    print!("\n{:4}: ", i + 1);
                }
                i += 1;
            }
            CoroutineState::Complete(v) => {
                println!("\n\ntotal: {}", v.len() + 1);
                break;
            }
        }
    }
}

https://play.rust-lang.org/?version=nightly&mode=release&edition=2024&gist=e1934ace1f900b5a961982899b4b8e15