Replacing Python(roscidus.com)

    foo :: Int -> Int

    use std::option::Option;

    fn call_me_maybe(x: int) -> Option<int> {
        if(x > 5) {
            Some(x)
        } else {
            None
        }
    }

    fn main() {
        let i = 6;
        match call_me_maybe(i) {
            Some(x) => println!("Yes! {:i}", x),
            None    => println!("nope"),
        }
    }

    rust.rs:13:8: 15:9 error: non-exhaustive patterns: None not covered
    rust.rs:13         match call_me_maybe(i) {
    rust.rs:14             Some(x) => println!("Yes! {:i}", x),
    rust.rs:15         }

    let i = 6;
    i = i + 5;

    rust.rs:3:8: 3:9 error: re-assignment of immutable variable `i`
    rust.rs:3         i = i + 5;
                  ^
    rust.rs:2:12: 2:13 note: prior assignment occurs here
    rust.rs:2         let i = 6;

    fn main() {
        let i: ~int = ~6; // read: i is an owned pointer to an int.
        let j: @int = @6; // read: j is an managed pointer to an int.
        let k = i;
        let l = j;
        println(i.to_str()); // error: use of moved value: `i`
        println(j.to_str()); // this is fine
    }

    fn main() {
        let i: ~int = ~6; // read: i is an owned pointer to an int.
        let j: @int = @6; // read: j is an managed pointer to an int.

        do spawn {
            println(i.to_str()); // fine, prints
        }
        println(i.to_str()); // you can't use it after you've given it away, either!
        // error: use of moved value: `i`
        // println(i.to_str()); // 
        //        ^
        //note: `i` moved into closure environment here because it has type `~fn:Send()`, which is non-copyable (perhaps you meant to use clone()?)
        //do spawn {
        //    println(i.to_str()); // fine, prints
        //} 

        do spawn {
            println(j.to_str()); // error: cannot capture variable of
                                 // type `@int`, which does not fulfill
                                 // `Send`, in a bounded closure
        }
    }