Crate statemachine_rs[−][src]

A zero dependency crate to implement state machine.

Let's have a look at the following simple example. This example shows the state machine can transit its number (it called current_state in this machine) from given string ("next") and then, it produces outputs.

use statemachine_rs::machine::{builder::StateMachineBuilder, StateMachine};

let sm = StateMachineBuilder::start()
    .initial_state(1)
    .transition(|state, input| match (state, input) {
        (1, "next") => 2,
        (2, "next") => 3,
        _ => unreachable!(),
    })
    .build()
    .unwrap();

assert_eq!(1, sm.current_state());
sm.consume("next");
assert_eq!(2, sm.current_state());

You can assemble your state machine by using statemachine_rs::machine::builder::StateMachineBUilder. StateMachineBuilder::initial_state() initializes the initial state of its machine. StateMachineBuilder::transition() defines the transition model.

Of cource we can use enums for representing states and inputs. Let's have a look at another example.

The following example describes if you press the button, the state turns to be On. Otherwise, Off.

use statemachine_rs::machine::{builder::StateMachineBuilder, StateMachine};

#[derive(Clone, Debug, PartialEq)]
enum ButtonState {
    On,
    Off,
}

enum Input {
    Press,
}

let sm = StateMachineBuilder::start()
    .initial_state(ButtonState::Off)
    .transition(|state, input| match (state, input) {
        (ButtonState::On, Input::Press) => ButtonState::Off,
        (ButtonState::Off, Input::Press) => ButtonState::On,
    })
    .build()
    .unwrap();

assert_eq!(ButtonState::Off, sm.current_state());
sm.consume(Input::Press);
assert_eq!(ButtonState::On, sm.current_state());

Crate statemachine_rs[−][src]

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