Challenge #236 [Easy] Random Bag System

main.rs

extern crate rand;

use rand::Rng;

use std::option::Option;

struct Bag {
    contents: Vec<char>,
    rng: rand::ThreadRng,
}

fn new_bag() -> Bag {
    Bag {
        contents: Vec::new(),
        rng: rand::thread_rng(),
    }
}

impl Iterator for Bag {
    type Item = char;

    fn next(&mut self) -> Option<Self::Item> {
        if !self.contents.is_empty() {
            self.contents.pop()
        } else {
            self.contents = vec!['O', 'I', 'S', 'Z', 'L', 'J', 'T'];
            self.rng.shuffle(&mut self.contents);
            self.contents.pop()
        }
    }
}


fn main() {
    let mut bag = new_bag();
    for c in (&mut bag).take(50) {
        print!("{}", c);
    }
    print!("\n");
}