Interesting implementation of state machine in Golang

state_machine.go

package main

import "fmt"

type connection struct {
	closed bool
	usage  int
}
type state func(*connection) state

func begin(c *connection) state {
	if c.closed {
		return end
	}

	c.usage++
	return second
}

func second(c *connection) state {
	if c.closed {
		return end
	} else {
		c.usage++
		return third
	}
}

func third(c *connection) state {
	const maxUsage = 10

	c.usage++
	if c.usage > maxUsage {
		return end
	}

	return third
}

func end(*connection) state {
	return nil
}

func main() {
	c := &connection{}

	state := begin
	for {
		state = state(c)
		fmt.Println(c)
		if state == nil {
			fmt.Println("breaking the loop")
			break
		}
	}
}