Is it possible to send closures via channels?

Question

I would like to send a closure via channels:

use std::thread;
use std::sync::mpsc;

#[derive(Debug)]
struct Test {
    s1: String,
    s2: String,
}

fn main() {         


        

Answer 1

The accepted answer doesn't go into detail, but you can send closures to threads via channels, even on stable, if you don't use FnOnce:

use std::thread;
use std::sync::mpsc;

struct RawFunc {
    data: Box,
}

impl RawFunc {
    fn new(data: T) -> RawFunc
    where
        T: Fn() + Send + 'static,
    {
        return RawFunc {
            data: Box::new(data),
        };
    }

    fn invoke(self) {
        (self.data)()
    }
}

fn main() {
    // Local
    let x = RawFunc::new(move || {
        println!("Hello world");
    });
    x.invoke();

    // Via channel
    let (sx, rx) = mpsc::channel::();
    sx.send(RawFunc::new(move || {
        println!("Hello world 2");
    })).unwrap();
    let output = rx.recv().unwrap();
    output.invoke();

    // In a thread
    let guard = thread::spawn(move || {
        let output = rx.recv().unwrap();
        output.invoke();
    });

    sx.send(RawFunc::new(move || {
        println!("Hello world 3!");
    })).unwrap();

    guard.join().unwrap();

    // Passing arbitrary data to a thread
    let (sx, rx) = mpsc::channel::();
    let guard = thread::spawn(move || {
        let output = rx.recv().unwrap();
        output.invoke();
    });

    let foo = String::from("Hello World 4");
    sx.send(RawFunc::new(move || {
        println!("Some moved data: {:?}", foo);
    })).unwrap();

    guard.join().unwrap();
}