gistfile1.rs

use std::cell::{Ref,RefCell};

#[deriving(Show)]
struct Creature {
    x: int
}

struct Foo {
    creatures: Vec<RefCell<Creature>>
}

impl Foo {
    fn creature_at<'a>(&'a self, x: int) -> Option<Ref<'a, Creature>> {
        match self.creatures.iter().find(
            |cr| match cr.try_borrow() {
                Some(cr) => cr.x == x,
                None => false
            }
        ) {
            Some(cr) => Some(cr.borrow()),
            None => None
        }
    }
}

fn main() {
    let foo = Foo {
        creatures: vec!(RefCell::new(Creature { x: 3 }), RefCell::new(Creature { x: 4 }))
    };
    println!("{}", foo.creature_at(4).map(|c| *c));
}