Trait Transition 

pub trait Transition<DestinationState>: Into<DestinationState> + State {
    // Required method
    fn guard(&self) -> TransitGuard;

    // Provided method
    fn action(&mut self) { ... }
}

Trait that must be implemented by a state that want to transition to DestinationState.

All states can have none or many transitions. On top of the transition trait the state must implement the Into<DestinationState> trait to specify what happens with the source state data while transitioning and how the destination state is generated. The action method is run once the transition executes. The only non optional method is the guard function that specifies when the state transitions.

Required Methods

fn guard(&self) -> TransitGuard

Specifies when the state has to transit. Return TransitGuard::Remain to remain in the current state and TransitGuard::Transit to transit into the next one. This is the only function that must be implemented by the transition. The others are optional and situational.

    fn guard(&self) -> TransitGuard {
        let foo = 0;
        if foo == 0 {
            TransitGuard::Remain
        } else {
            TransitGuard::Transit
        }
    }

Provided Methods

fn action(&mut self)

Implement any behavior that hast to be executed when exiting the state.

    fn action(&mut self) {
        println!("Called while transitioning to another state");
    }

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors