def require_rules(rules, locals = {}, target = binding)
  locals.each { target.local_variable_set(_1, _2) }
  path = File.join(Dir.getwd, rules)
  target.eval(
    if File.readable?(path)
      File.read(path)
    elsif File.readable?("#{path}.rb")
      File.read("#{path}.rb")
    elsif File.readable?("#{path}.rules")
      File.read("#{path}.rules")
    else
      raise LoadError, "#{path} is not readable"
    end
  )
end