Difficulty with implementing a state machine in Rust using enums and match statements
I tried several approaches but none seem to work. I've looked through the documentation and I'm still confused about I'm trying to implement a simple state machine in Rust using enums and match statements, but I'm running into issues with ensuring that the state transitions are valid at compile-time. My state machine has three states: `Idle`, `Processing`, and `Completed`. I want to make sure that it can only transition from `Idle` to `Processing` and from `Processing` to `Completed`, but I keep getting borrow checker errors when I try to manage the state transitions. Here’s a simplified version of my code: ```rust enum State { Idle, Processing, Completed, } struct StateMachine { state: State, } impl StateMachine { fn new() -> Self { StateMachine { state: State::Idle } } fn process(&mut self) { match self.state { State::Idle => { println!("Starting processing..."); self.state = State::Processing; } State::Processing => { println!("Processing..."); self.state = State::Completed; } State::Completed => { println!("Already completed."); } } } } ``` When I call `process()` on my `StateMachine`, it compiles fine, but I get an behavior if I try to call `process()` a second time after it has transitioned to `Completed`. The behavior message is: `behavior[E0507]: want to move out of borrowed content`. I initially thought this was a question with mutable references or ownership, but I’m not quite sure how to structure my match statement to handle this better. I want to follow Rust's ownership principles without running into borrow checker issues. Is there a better design pattern I should consider for this state machine, or is there a way to structure my code to avoid this behavior? Any insights would be appreciated! Thanks in advance! For reference, this is a production web app. Thanks for taking the time to read this! What would be the recommended way to handle this?