def constant_node(name, value, options = {})
      attr_reader name.to_sym
      define_method("parse_#{name}".to_sym) do
        instance_variable_set("@#{name}", value)
      end
      register(name, options[:private])
    end
def constant_node(name, value, options = {})
      attr_reader name.to_sym
      define_method("parse_#{name}".to_sym) do
        instance_variable_set("@#{name}", value)
      end
      register(name, options[:private])
    end
Defines a method on your class returning a constant.