etsm 0.1.3

c# etsm

Tiny state machine for c#, see etsm

Description

Implement a bare bones state machine in many languages. This library aim to be simple as possible and support only basic features:

• states on object (owner)
• enter/exit methods
• virtual state methods
• is in
• unrestricted transitions
• no runtime allocation

Install

Edit your vcproj and add:

  <ItemGroup>
    <PackageReference Include="etsm" Version="x.y.z" />
  </ItemGroup>

latest version:

Or

Add this file directly into your project: etsm

Example

Simple

Declare state machine and state in your class

    public class Foo
    {
        private StateMachine<State> stateMachine;
        private State stateA;
        private State stateB;
    ...

Create them in the constructor and bind enter/exit

        public Foo()
        {
            stateMachine = new StateMachine<State>();
            stateA = new State(EnterA, ExitA);
            stateB = new State(EnterB, null);
        }

Make your callback methods

        void EnterA()
        {
            System.Console.Write(" ->A ");
        }

        void ExitA()
        {
            System.Console.Write(" A-> ");
        }

        void EnterB()
        {
            System.Console.Write(" ->B ");
        }

Execute transitions

        public void Run()
        {
            stateMachine.Transition(stateA);
            stateMachine.Transition(stateB);
            stateMachine.Transition(null);
        }

Output: " →A A-> →B "

full sample here

Virtual State Methods

    // Define your own state and add Run Action.
    public class State : Etsm.State
    {
        public Action? Run { get; private set; }

        public State(Action? enter, Action? exit, Action? run = null)
            : base(enter, exit)
        {
            Run = run;
        }
    }

    public class Foo
    {
        private StateMachine<State> stateMachine;
        private State stateA;
        private State stateB;

        public Foo()
        {
            stateMachine = new StateMachine<State>();
            stateA = new State(null, null, RunA);
            stateB = new State(null, null, RunB);
        }

        private void RunA()
        {
            Console.Write(" A ");
        }

        private void RunB()
        {
            Console.Write(" B ");
        }

        // call run on the current state
        private void Run()
        {
            stateMachine.CurrentState?.Run?.Invoke();
        }

        public void Test()
        {
            stateMachine.Transition(stateA);
            Run();
            stateMachine.Transition(stateB);
            Run();
        }
    }

Output: " A B "
full sample here