hook_method.rb

module HookMethod
  def hook_method(hook, *methods)
    methods.each do |method|
      orig = "#{method}_without_logging".to_sym
      if instance_methods.include?(orig)
        raise NameError, "#{orig} isn't a unique name"
      end

      alias_method orig, method

      define_method(method) do |*args, &block|
        result = send(orig, *args, &block)
        send(hook)
        result
      end
    end
  end
end

def print_message
  puts 'hook message'
end

Array.extend HookMethod
Array.hook_method(:print_message, :first, :at)
puts [1, 2, 3].first
puts [2, 3, 4].at(1)