begin
  require 'features/ruby18'
rescue LoadError
end

module RRB
  
  class RRBError < StandardError
  end

  module Once
    def once(*ids)
      for id in ids
	module_eval <<-"end;"
	  alias_method :__#{id.to_i}__, :#{id.to_s}
	  private :__#{id.to_i}__
	  def #{id.to_s}(*args, &block)
	    (@__#{id.to_i}__ ||= [__#{id.to_i}__(*args, &block)])[0]
	  end
	end;
      end
    end
  
    private :once

  end

end