FluentStateMachine

Finite-state machine (FSM) with a fluent interface and mediators compatibility

Example

enum States { S1, S2, S3 }
enum Events { E1, E2, E3 }

var fsm = new FsmBuilder<States, Events>(States.S1)
    .OnEnter(x => Console.WriteLine($"State change to {x.State} from {x.PrevState}"))
    .State(States.S1)
        .On(Events.E1).Execute(x => { /* some operations */ return "some results"; })
        .On(Events.E2).JumpTo(States.S2)
    .State(States.S2)
        .On(Events.E3).Enable(x => /* some conditions */ true).JumpTo(States.S3)
    .State(States.S3)
        .OnEnter(x => Console.WriteLine($"Enter to final state"))
    .Build();


Console.WriteLine(fsm.Trigger(Events.E1));
fsm.Trigger(Event.E2);
fsm.Trigger(Event.E3);


// Console output:
// some results
// State change to S2 from S1
// State change to S3 from S2
// Enter to final state

ReadmeExample1.cs

Example with type-based events

class Event1 : IFsmEvent<string>
{
    public int SomeProp { get; set; }
}

class Event2 : IFsmEvent;
class Event3 : IFsmEvent;

var fsm = new FsmBuilder<States, Type>(States.S1)
    .OnEnter(x => Console.WriteLine($"State change to {x.State} from {x.PrevState}"))
    .State(States.S1)
        .On<Event1, string>().Execute(x => $"{x.Data.SomeProp} results")
        .On<Event2>().JumpTo(States.S2)
    .State(States.S2)
        .On<Event3>().JumpTo(States.S3)
    .State(States.S3)
        .OnEnter(x => Console.WriteLine($"Enter to final state"))
    .Build();


Console.WriteLine(
    fsm.Trigger(new Event1 { 
        SomeProp = 123 
    }));

fsm.Trigger(new Event2());
fsm.Trigger(new Event3());


// Console output:
// 123 results
// State change to S2 from S1
// State change to S3 from S2
// Enter to final state

ReadmeExample2.cs

Example of use for workflows

Example with mediator (MediatR)