Config.rb

require 'yaml'

module Config
  class << self
    def configure(file_or_yaml=nil)
      @@configuration ||= {}
      
      if file_or_yaml
        @@configuration = File.exists?(file_or_yaml) ? YAML.load_file(file_or_yaml) : YAML.load(file_or_yaml)
      end
      
      yield(self) if block_given?
    end
    
    def method_missing(method, *args)
      method = method.to_s
      
      case
      when method.to_s.include?("=") # make this better (regex)
        @@configuration[method.to_s.gsub("=", "")] = args.first if args.first
      when (value = @@configuration[method])
        value
      else
        # Here we can either raise no_method for Object or nil...
        # super(method.to_sym, *args)
        nil
      end
    end
  end
end

# Standalone (without YAML)

Config.configure do |config|
  config.example_one = "One"
  config.example_two = "Two"
end

puts Config.example_one
puts Config.example_two
puts Config.doesnt_exist



# With YAML (inline)

yaml = <<CONTENT

example_one: "Oooooo"
example_two: "It loads from YAML too!"

CONTENT

Config.configure(yaml)

puts Config.example_one
puts Config.example_two



# With YAML (file)

Config.configure("config.yml")

puts Config.example_one
puts Config.example_two



# Or go nuts (inline yaml and block)

yaml = <<CONTENT

example_three: "Oooooo"
example_four: "It loads from YAML too!"

CONTENT

Config.configure(yaml) do |config|
  config.example_one = "One"
  config.example_two = "Two"
end

puts Config.example_one
puts Config.example_two
puts Config.example_three
puts Config.example_four

config.yml

example_one: "YAMLLY"
example_two: "YAMLLY AHA"