counter.cr

require "spec"

class Counter(B)
  include Iterator(Array(B))

  def initialize(@size : Int, @range : Range(B, E))
    @array = Array.new(@size, @range.begin)
    @stop = false
  end

  def next
    return stop if @stop == true

    value = @array.dup

    i = 0
    while true
      if @array[i] == @range.end
        if i == @array.size - 1
          @stop = true
          break
        end
        @array[i] = @range.begin
        i += 1
        next
      end
      @array[i] = @array[i].succ
      break
    end

    value
  end

  def rewind
    @array.fill(@range.begin)
    @stop = false
    self
  end
end

describe Counter do
  it "counts" do
    counter = Counter.new(2, 'a'..'b')
    counter.to_a.should eq([['a', 'a'], ['b', 'a'], ['a', 'b'], ['b', 'b']])
  end
end