Some configuration techniques in Ruby

foobar_config.rb

module Foobar
  module Config
    class << self
      attr_writer :foo, :bar, :baz

      def foo(value = nil)
        if value
          self.foo = value
        else
          @foo
        end
      end

      def bar(value = nil)
        if value
          self.bar = value
        else
          @bar
        end
      end

      def baz(value = nil)
        if value
          self.baz = value
        else
          @baz
        end
      end
    end
  end



  def self.config(&block)
    if block_given?
      if block.arity > 0
        yield Config
      else
        Config.class_exec &block
      end
    else
      Config
    end
  end
end

foobar_config_2.rb

module Foobar
  module Config
    ATTRIBUTES = [:foo, :bar, :baz]

    class << self
      attr_writer *ATTRIBUTES


      ATTRIBUTES.each do |attribute|
        class_eval "def #{attribute}(value = nil)
          if value
            self.#{attribute} = value;
          else
            @#{attribute}
          end
        end", __FILE__, __LINE__+1
      end

    end
  end



  def self.config(&block)
    if block_given?
      if block.arity > 0
        yield Config
      else
        Config.class_exec &block
      end
    else
      Config
    end
  end
end

how_to_use.rb

conf_module = Foobar.config

Foobar.config.foo = 1

Foobar.config do |conf|
  conf.foo = "hello"
  conf.bar = "good bye"
end

Foobar.config do
  bar 42
  baz 1337
end