Rust clone_army! macro

clone_army.rs

use std::sync::Arc;

macro_rules! clone_army {
    ($vars:tt | | $body:expr) => {
        clone_army!(@emit $vars [] [] $body)
    };
    ($vars:tt move | | $body:expr) => {
        clone_army!(@emit $vars [] [move] $body)
    };
    ($vars:tt || $body:expr) => {
        clone_army!(@emit $vars [] [] $body)
    };
    ($vars:tt move || $body:expr) => {
        clone_army!(@emit $vars [] [move] $body)
    };
    ($vars:tt |$($param:ident),+| $body:expr) => {
        clone_army!(@emit $vars [$($param),*] [] $body)
    };
    ($vars:tt move |$($param:ident),+| $body:expr) => {
        clone_army!(@emit $vars [$($param),*] [move] $body)
    };
    (@emit [$($var:ident),*] [$($param:ident),*] [$($mov:ident)*] $body:expr) => {{
        $(let $var = $var.clone();)*
        $($mov)* |$($param),*| $body
    }}
}

#[derive(Debug)]
struct S;

impl Clone for S {
    fn clone(&self) -> Self {
        println!("cloning!");
        S
    }
}

fn main() {
    let a = Arc::new(42);
    let b = S;
    clone_army!([a, b] move || println!("{} {:?}", a, b))();
}