1 unstable release
0.1.0-alpha | Feb 25, 2023 |
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#1919 in Rust patterns
28KB
598 lines
restate
restate
is a Rust library that provides a simple way of defining and using finite state machines.
Installation
Add the following to your Cargo.toml file:
[dependencies]
restate = "0.1.0-alpha"
Or use
cargo add restate
Usage
restate can be used to define state machines that can transition between different states based on events. Here is an example:
use restate::blocking::*;
#[derive(Debug, Clone, PartialEq, Eq)]
struct Active;
#[derive(PartialEq, Eq)]
enum CountEvent {
Increment,
Decrement,
}
let mut sm = Machine::with_context(0)
.on_next(
Builder::self_transition(Active, CountEvent::Increment).action(
|cx: ContextMut<Active, CountEvent, i32>| {
*cx.context += 1;
},
),
)
.on_next(
Builder::self_transition(Active, CountEvent::Decrement).action(
|cx: ContextMut<Active, CountEvent, i32>| {
*cx.context -= 1;
},
),
)
.start(Active);
sm.send(CountEvent::Increment).unwrap();
sm.send(CountEvent::Increment).unwrap();
sm.send(CountEvent::Increment).unwrap();
sm.send(CountEvent::Decrement).unwrap();
assert_eq!(*sm.context(), 2);
This example creates a state machine with a single state Active and two events Increment and Decrement. It then adds a self-transition for each event that increments or decrements an integer in the machine's context. Finally, it starts the machine with the Active state, sends some events to it, and checks the final value of the context.
License
This library is licensed under the MIT license. See the LICENSE file for more details.