Macro defer 

macro_rules! defer {
    ($func:expr) => { ... };
}

Used for deferring a FnOnce(). Deferred functions will called at the end of the scope.

Example

use deferrer::defer;
use std::cell::RefCell;

let mut s = RefCell::new(String::from("Hello"));
{
	defer!( || s.borrow_mut().push_str(" world!") );
	assert_eq!(*s.borrow(), "Hello");
}
assert_eq!(*s.borrow(), "Hello world!");