Crystal module playing

modules.cr

module Ord(A)
  abstract def cmp(a : A, b : A)
end

class IntOrd
  include Ord(Int32)

  def cmp(a, b)
    a > b
  end
end

class Sorter(A)
  getter :order

  def initialize(@order : Ord(A))
  end

  def sort(list : Array(A))
    i = 0
    j = list.size - 1
    aux = nil
    while i < j
      if order.cmp(list[i], list[j])
        aux = list[i]
        list[i] = list[j]
        list[j] = aux
      end
      i += 1
      j -= 1
    end
    list
  end
end

ls = [5, 5, 2]
puts Sorter(Int32).new(IntOrd.new).sort(ls)
puts ls