> Rust has a feature called traits. Traits are a way of doing compile-time static dispatch, and can also be used to do runtime dispatch (although in practice th

> Rust has a feature called traits. Traits are a way of doing compile-time static dispatch, and can also be used to do runtime dispatch (although in practice that’s rarely useful.) Hmm, I dunno about that. If you need to keep a collection of callbacks, that would most certainly be a collection of Fn/FnMut trait objects, that is this: struct Thing { callbacks: Vec<Box<FnMut(i32) -> i32>> } and not this: struct Thing<F> where F: FnMut(i32) -> i32 { callbacks: Vec<F> } The same applies for any use of traits where the exact impl to be used is not known until runtime, like choosing a behavior from some set of behaviors in a configuration file.