anon_struct.go

package main

import (
	"fmt"
	"time"
)

func intervalIterator(from, to time.Time, interval time.Duration) struct {
	hasNext func() bool
	get     func() time.Time
} {
	now := from
	return struct {
		hasNext func() bool
		get     func() time.Time
	}{
		func() bool { return now.Before(to) },
		func() time.Time { defer func() { now = now.Add(interval) }(); return now },
	}
}

func main() {
	now := time.Now()
	itr := intervalIterator(
		now.Add(-24*time.Hour).Truncate(time.Hour),
		now,
		time.Hour,
	)

	for itr.hasNext() {
		fmt.Println(itr.get())
	}
}