redflag_with_comment.rb

lambda {
  setups = []
  events = {}
  
  Kernel.send :define_method, :event do |name, &block|
    events[name] = block
  end
  
  Kernel.send :define_method, :setup do |&block|
    setups << block
  end
  
  Kernel.send :define_method, :each_event do |&block|
    events.each_pair do |name, event|
      block.call name, event
    end
  end
  
  Kernel.send :define_method, :each_setup do |&block|
    setups.each do |setup|
      block.call setup
    end
  end
}.call

Dir.glob('*events.rb').each do |file|
  load file
  # '*events.rb'でため込まれているけども、
  # lambda内のローカル変数setups, events は見えない。
  # p events, setups
  # => undefined local variable or method `events' for main:Object (NameError)
  
  each_event do |name, event|
    env = Object.new
    each_setup do |setup|
      env.instance_eval &setup
    end
    puts "ALERT: #{name}" if env.instance_eval &event
  end
end