# Mutable Mutable is a crate to keep track of changes in structures\ It is still very much WIP Here is a small example: ```rust use mutable::Mutable; use mutable_derive::Mutable; #[derive(Mutable)] struct Simple { size: usize, } #[derive(Mutable)] struct Complex { id: String, value: Simple, } fn main() { let mut c0 = Complex { id: "a".to_string(), value: Simple { size: 32 } }; let c1 = Complex { id: "b".to_string(), value: Simple { size: 64 } }; assert_eq!(c0.update(c1), vec![ ComplexMutation::Id(("a".to_string(), "b".to_string())), ComplexMutation::Value(SimpleMutation::Size((32, 64))) ]); } ```