variant of merge that separates Analysis from Action.

gistfile1.rs

fn merge<T: Ord + Clone>(l1: &[T], l2: &[T]) -> ~[T] {
    let mut merged = ~[];
    let mut l1 = l1.to_owned().move_iter().peekable();
    let mut l2 = l2.to_owned().move_iter().peekable();

    enum Step { Left, Right, Done }

    loop {
        let step = {
            let a = l1.peek();
            let b = l2.peek();
            match (a, b) {
                (None, None) => Done,
                (Some(el1), None) => { merged.push(el1.clone()); Left }
                (None, Some(el2)) => { merged.push(el2.clone()); Right }
                (Some(el1), Some(el2)) => {
                    if el1 < el2 {
                        merged.push(el1.clone()); Left
                    } else {
                        merged.push(el2.clone()); Right
                    }
                }
            }
        };
        match step {
            Left => l1.next(),
            Right => l2.next(),
            Done => return merged
        };
    }
}

fn main() { }