s.FSM - sengine API

Minimal finite state machine with explicit transitions between states.

FSM keeps track of one current state and only allows transitions that are explicitly registered on that state. This keeps state flow easy to reason about: if there is no transition, goto simply does nothing.

Typical usage:

var idle = new State();
var walking = new State();

idle[walking] = () -> trace("start walking");
walking[idle] = () -> trace("stop walking");

var fsm = new FSM(idle);
fsm.goto(walking);

Constructor

`new(?state:State)`

Creates a finite state machine.

Parameters:

`state`	Initial state. May be `null`, in which case `goto` cannot do anything until a state is assigned.

Variables

`current:State`

Current active state.

This field can be assigned directly, but in normal usage transitions should go through goto so transition callbacks are respected.

Methods

`goto(to:State):Void`

Transitions to another state if the current state defines a transition for it.

If the transition exists, the target state becomes current and the transition callback is invoked immediately.