stator

Clearly manage state transitions using closures in Rust.

Create your state definition struct

struct States;
impl States
{
    fn a() -> &'static str { "a" }
    fn b() -> &'static str { "b" }
    fn c() -> &'static str { "c" }
}

Create a new Stator object, specifying initial state

let mut state = Stator::new(States::a());

Add some state handlers

1. Specify Stator::any_state() as the first parameter and a custom state as the second to execute on state enter
2. Specify a custom state as the first parameter and Stator::any_state() as the second to execute on state exit
3. Specify a custom state as both parameters to execute on transition between the two states
4. Specify Stator::any_state() as both parameters to execute on every state change

state.add_handler(States::a(), States::b(), |from: &String|
{
    println!("a -> b");
});

state.add_handler(Stator::any_state(), States::b(), |from: &String|
{
    println!("? -> b");
});

state.add_handler(States::a(), Stator::any_state(), |from: &String|
{
    println!("a -> ?");
});

state.add_handler(Stator::any_state(), States::a(), |from: &String|
{
    println!("? -> a");
});

Enter a new state at any time

Protip: Don't pass Stator::any_state() to the enter() method.

state.enter(States::b());

Enjoy the irony

Stator: The stator is the stationary part of a rotary system, found in electric generators, electric motors, sirens, or biological rotors.