refinements.rb

require_relative 'library'

# This is the library:
#
# class Lord
#   def self.printar(x)
#     puts x.reverse
#   end
# end

module StringExtensions
  refine String do
    def reverse
      "Refined reverse()"
    end
  end

  refine Fixnum do
    def succ
      self + 2
    end
  end
end

module StringStuff
  using StringExtensions

  puts "abcd".reverse # => Refined reverse()
  Lord.printar("abcd") # => bcda
end

class CrazyString
  using StringExtensions

  def reverse
    "nthoeunth".reverse
  end
end

cs = CrazyString.new

puts cs.reverse # => Refined
Lord.printar(cs) # => Refined