package main

import (
	"fmt"
	"iter"
)

// As long as the loop continues to run, yield will keep returning true,
// indicating that more values exist.
// However, if the loop terminates (for instance, due to a break or return),
// yield will return false.
// This allows to perform any necessary cleanup.
func generateFibonacci() iter.Seq[int] {
	return func(yield func(int) bool) {
		a, b := 1, 1

		for {
			if !yield(a) {
				fmt.Println("Stop sequence")
				return
			}

			a, b = b, a+b
		}
	}
}

func main() {
	for v := range generateFibonacci() {
		fmt.Println(v)

		if v > 10 {
			break
		}
	}
}

// $ go run main.go 
// 1
// 1
// 2
// 3
// 5
// 8
// 13
// Stop sequence