go-like defer for rust

defer.rs

#[feature(macro_rules)];

struct ScopeCall<'cls> {
    c: 'cls ||
}
#[unsafe_destructor]
impl<'cls> Drop for ScopeCall<'cls> {
    fn drop(&mut self) {
        (self.c)();
    }
}

macro_rules! defer(
    ($e:expr) => (
        let _scope_call = ScopeCall{ c: || -> () { $e; } };
    )
)

fn main() {
    let x = ~42u8;
    defer!(println!("defer 1"));
    defer!({println!("defer 2"); println!("{}", *x)});
    println!("normal execution {}", *x);
}

output

$ ./t.exe
normal execution 42
defer 2
42
defer 1