Macro defer 

macro_rules! defer {
    ($($t:tt)*) => { ... };
}

Calls the given closure at the end of the current scope

Example

use rs42::defer;
use std::cell::Cell;

let nb = Cell::new(0);
{
    defer!(nb.set(1));
    assert_eq!(nb.get(), 0);
}
assert_eq!(nb.get(), 1);