require 'benchmark'

class Object
  def either?(*args)
    args.include? self
  end
  def in?(*args)
    case args.length
    when 0
      false
    when 1
      self == args[0]
    when 2
      self == args[0] || self == args[1]
    else
      args.include?(self)
    end
  end
end

count = 10000000

Benchmark.bmbm do |x|

  x.report "includes?" do
    count.times do
      [:one, :two].include?(:one)
    end
  end

  x.report "either?" do
    count.times do
      :one.either?(:one, :two)
    end
  end

  x.report "compare" do
    count.times do
      :one == :one or :one == :two
    end
  end
end