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# statemachine-rs
A zero dependency crate to implement state machine.
### Usage
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.
```rust
use statemachine_rs::machine::{builder::StateMachineBuilder, StateMachine};
fn main() {
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 `enum`s 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`.
```rust
use statemachine_rs::machine::{builder::StateMachineBuilder, StateMachine};
#[derive(Clone, Debug, PartialEq)]
enum ButtonState {
On,
Off,
}
enum Input {
Press,
}
fn main() {
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());
}
```
### License
MIT
### Contribution
All contributions are welcome.
If you have an idea to improve this crate, create new issue or submit new pull request.
License: MIT