gistfile1.rb

class Module
  def name_finder(*methods)
    methods.each do |method|
      raise TypeError.new("method name is not symbol") unless method.is_a?(Symbol)
      metaclass = class << self; self; end
      metaclass.send(:define_method, method) do
        instance_variable_get(self.find_by_name(method.to_s))
      end
    end
  end
end

class Type
  set_table_name 'types'
  name_finder :mail, :phone, :sms
end

Type.mail