# File lib/vpim/vevent.rb, line 169
        def add_rrule(rule = nil, &block) #:yield: Rrule::Maker
          # TODO - should be in Property::Reccurrence::Set
          unless rule
            rule = Rrule::Maker.new(&block).encode
          end
          @comp.properties.push(Vpim::DirectoryInfo::Field.create("RRULE", rule))
          self
        end