Move Eval from Runtime to Parse Time

You need to use eval but want to limit the number of times eval is necessary.

Move the use of eval from within the method definition to defining the method itself.

class Person
  def self.attr_with_default(options)
    options.each_pair do |attribute, default_value|
      define_method attribute do
        eval "@#{attribute} ||= #{default_value}"
      end
    end
  end

  attr_with_default :emails => "[]", 
                              :employee_number   =>"EmployeeNumberGenerator.next"
end

class Person
  def self.attr_with_default(options)
    options.each_pair do |attribute, default_value|
      eval "define_method #{attribute} do
               @#{attribute} ||= #{default_value}
              end"
    end
  end
  
    attr_with_default :emails => "[]", 
                    :employee_number
                    =>"EmployeeNumberGenerator.next"
end