Kotlin Standard Library Cookbook

How to do it...

1. Let's start with implementing the Iterator interface for the LocalDate type. We are going to create a custom LocalDateIterator class, which implements the Iterator<LocalDate> interface:

class DateIterator(startDate: LocalDate,                   val endDateInclusive: LocalDate,                   val stepDays: Long) : Iterator<LocalDate> {    private var currentDate = startDate    override fun hasNext() = currentDate <= endDateInclusive    override fun next(): LocalDate {        val next = currentDate        currentDate = currentDate.plusDays(stepDays)        return next    }}

2. Now, we can implement the progression for the LocalDate type. Let's create a new class called DateProgression, which is going to implement the Iterable<LocalDate> and ClosedRange<LocalDate> interfaces:

class DateProgression( ...