Minimal "states" mixin in Ruby

showcase.rb

module HasStates
  def state_field(column, state_names)
    state_names.each do |name|
      define_method("#{name}?") do
        self.send(column) == name
      end
    end
  end
end

class MyModel
  extend HasStates
  state_field :status, [:start, :end]

  # IRL this can be an ActiveRecord attribute, no need to def
  def status
    :start
  end
end

m = MyModel.new
puts m.start? #=> true
puts m.end?   #=> false