Passing mutable self reference to method of owned object

by

Currently your Ball struct needs to know about the Field it’s contained in to be able to update itself. This doesn’t compile because the result would be cyclic references combined with mutation. You could make this work by using Cell or RefCell (the latter having a performance cost) but it would be even better to structure the code differently. Let the Field struct check for and resolve Ball–Ball and Ball–Wall collisions. The Ball struct’s update function can handle updating the Ball‘s position.

// Ball's update function
fn update(&mut self) {
    // update position
}

// Field's update function
fn update(&mut self) {
    for ball in self.balls.iter_mut() {
        ball.update();
    }

    // check for collisions

    // resolve any collisions
}

More Related Contents:

  1. Why can’t I store a value and a reference to that value in the same struct?
  2. Cannot move out of value which is behind a shared reference when unwrapping
  3. Why does refactoring by extracting a method trigger a borrow checker error?
  4. Temporarily move out of borrowed content
  5. Returning a reference from a HashMap or Vec causes a borrow to last beyond the scope it’s in?
  6. Mutably borrow one struct field while borrowing another in a closure
  7. Do mutable references have move semantics?
  8. Cannot borrow as immutable because it is also borrowed as mutable in function arguments
  9. Double mutable borrow error in a loop happens even with NLL on
  10. What are the options to end a mutable borrow in Rust?
  11. How to update-or-insert on a Vec?
  12. “borrowed value does not live long enough” when using the builder pattern
  13. How to use struct self in member method closure
  14. Can’t borrow mutably within two different closures in the same scope
  15. Temporary value is freed at the end of this statement [duplicate]
  16. How to use a struct’s member as its own key when inserting the struct into a map without duplicating it?
  17. How can I modify self in a closure called from a member function?
  18. How do I move out of a struct field that is an Option?
  19. Why does this mutable borrow live beyond its scope?
  20. Why can’t I reuse a &mut reference after passing it to a function that accepts a generic type?
  21. How do I convert a Vec to a Vec without copying the vector?
  22. Cannot move out of borrowed content when trying to transfer ownership
  23. How do you access enum values in Rust?
  24. Situations where Cell or RefCell is the best choice
  25. Why does my variable not live long enough?
  26. Why are recursive struct types illegal in Rust?
  27. How can I mutate other elements of a HashMap when using the entry pattern?
  28. How to embed resources in Rust executable?
  29. Extend lifetime of variable
  30. How to concatenate static strings in Rust

Leave a Comment