A tested, dynamic approach to building configuration objects on the fly

configurator.rb

class Configurator

  def self.configure(&block)
    configuration ||= new
    configuration.instance_eval(&block)
    return configuration
  end

  def respond_to_missing?(method_name, include_private = false)
    super unless self.instance_variables.include?(convert_method_to_symbol(method_name))
  end

  def method_missing(m, *args, &block)
    super(m, *args, &block) if respond_to?(m)

    ivar = convert_method_to_symbol(m)
    data = args.size == 1 ? args.first : args

    #define getter, setter and predicate methods
    self.class.__send__(:attr_accessor, ivar)
    self.class.__send__(:define_method, "#{ivar}?", proc { !!data })

    #set the value
    instance_variable_set("@#{ivar}", data)

    self
  end

  def convert_method_to_symbol(meth)
    meth.to_s.gsub('=', '').to_sym
  end
end

#Configurator.configure do |conf|
#  conf.port = 8080
#  conf.hostname = 'testing'
#  conf.password = '$3(r3t'
#end

require 'minitest/autorun'
require 'minitest/pride'

class TestConfigurator < Minitest::Test

  def test_config_methods
    @configuration =  Configurator.configure { |c| c.foo = 'meh' }

    assert_includes @configuration.methods, :foo
    assert_includes @configuration.methods, :foo?
    assert_includes @configuration.methods, :foo=
  end
end