fsm.go

package main

import (
	"fmt"

	"github.com/looplab/fsm"
)

type Turnstile struct {
	To  string
	FSM *fsm.FSM
	// InternalState for the FSM
	Profit int
}

func NewTurnstile(to string) *Turnstile {

	t := &Turnstile{
		To: to,
	}
	// List of events
	var events = fsm.Events{
		{Name: "push", Src: []string{"closed", "open"}, Dst: "closed"},
		{Name: "coin", Src: []string{"open", "closed"}, Dst: "open"},
	}
	// List of callbacks
	var callbacks = fsm.Callbacks{
		// The function we run when we enter the state
		"enter_state": func(e *fsm.Event) { t.enterState(e) },
		// Callback to change internal state
		"coin": func(e *fsm.Event) { t.Profit++ },
	}

	// Start new FSM with events and callbacks.
	t.FSM = fsm.NewFSM(
		"closed",
		// Define the transitions
		events,
		// Callbacks for the state changes
		callbacks,
	)

	return t
}

func (t *Turnstile) enterState(e *fsm.Event) {
	fmt.Printf("The turnstile to %s is %s\n", t.To, e.Dst)
}

func main() {
	t := NewTurnstile("heaven")

	fmt.Println("Enter coin! ")
	err := t.FSM.Event("coin")
	if err != nil {
		fmt.Println(err)
	}

	fmt.Println("Current profit: ", t.Profit)
	fmt.Println("Push!")
	err = t.FSM.Event("push")
	if err != nil {
		fmt.Println(err)
	}
	fmt.Println("Enter coin! ")
	err = t.FSM.Event("coin")
	if err != nil {
		fmt.Println(err)
	}
	fmt.Println("Enter coin! ")
	err = t.FSM.Event("coin")
	if err != nil {
		fmt.Println(err)
	}
	fmt.Println("Current profit: ", t.Profit)
	fmt.Println("Push!")
	err = t.FSM.Event("push")
	if err != nil {
		fmt.Println(err)
	}
}