shared global ruby configuration dsl example

global.rb

module App
  module Global
    extend self

    def self.configure(&block)
      instance_eval(&block) 
    end

    def [](key)
      config[key]
    end

    private

    def set(key, value)
      config[key] = value
    end

    def config
      @config ||= Hash.new
    end

    def method_missing(sym, *args)
      if sym.to_s =~ /(.+)=$/
        config[$1] = args.first
      else
        config[sym]
      end
    end

  end
end

App::Global.configure do
  set :a, 1
end

class A
  def test
    puts("A: a=#{App::Global.a.inspect}")
    puts("A: b=#{App::Global.b.inspect}")
    puts("A: c=#{App::Global[:c].inspect}")
  end
end


class B
  App::Global.configure do
    set :b, 2
  end

  def test
    App::Global.configure do
      set :c, 3
    end

    puts("B: a=#{App::Global[:a].inspect}")
    puts("B: b=#{App::Global[:b].inspect}")
    puts("B: c=#{App::Global.c.inspect}")
  end
end

a = A.new
b = B.new
a.test
b.test
a.test