attribute (Gem::Specification)

    # File lib/rubygems/specification.rb, line 158
      def self.attribute(name, default=nil)
        ivar_name = "@#{name}".intern
        if default.nil? then
          @@nil_attributes << ivar_name
        else
          @@non_nil_attributes << [ivar_name, default]
        end

        @@attributes << [name, default]
        @@default_value[name] = default
        attr_accessor(name)
      end