Threads can have task xor service semantics

thread_as_task_or_service.rs

use std::sync::mpsc::{Sender, Receiver};
use std::sync::mpsc;
use rayon::prelude::*;

fn main() {
    let (tx, rx): (Sender<u8>, Receiver<u8>) = mpsc::channel();
    // Thread as an event loop (service)
    // Long lived
    // May use messaging and shared state
    std::thread::spawn(move || {
        loop {😉
            // let e = events.next();
            // do_sume_cool_stuff(e);
            let e = rx.recv().unwrap();
            println!("{e}");
            if e == 3 {
                break
            }
        }
    });
    
    // Thread as a parallel function (task)
    // Only input and output
    // No messaging unless being silly.
    // Maybe shared state
    fn my_func(i: u8) -> u8 { i * i }
    let input = [(1u8, tx.clone()), (2u8, tx.clone()), (3u8, tx.clone())];
    let r: u8 = input.par_iter()
        .map(|(i, tx)| { 
            tx.send(*i).unwrap(); // Ok, we are silly 😉
            my_func(*i)
        })
        .sum();
    assert_eq!(r, 14);
    
    println!("Exit");
}