Rust Programming Cookbook

How to do it...

Let's create a test to establish the best way to share mutable ownership in just a few steps:

1. Let's create a couple of new functions inside the testing module:

    use std::cell::{Cell, RefCell};    use std::borrow::Cow;    use std::ptr::eq;    fn min_sum_cow(min: i32, v: &mut Cow<[i32]>) {        let sum: i32 = v.iter().sum();        if sum < min {            v.to_mut().push(min - sum);        }    }    fn min_sum_refcell(min: i32, v: &RefCell<Vec<i32>>) {        let sum: i32 = v.borrow().iter().sum();        if sum < min {            v.borrow_mut().push(min - sum);        }    }    fn min_sum_cell(min: i32, v: &Cell<Vec<i32>>) {        let mut vec = v.take();        let sum: i32 = vec.iter().sum();        if sum < min {            vec.push(min - sum);        }        v.set(vec);    }

2. These functions dynamically (based on incoming data) mutate a list of ...