+ # Creates and installs a new Action, one-time by default.
+ # _period_:: Action delay
+ # _opts_:: options for Action#new, see there
+ # _block_:: Action callback code
+ #
+ # Returns the id of the created Action
+ def add_once(period, opts = {}, &block)
+ self.add(period, {:repeat => false}.merge(opts), &block)
+ end
+
+ # blocks an existing Action
+ # _aid_:: Action id, obtained previously from add() or add_once()
+ def block(aid)
+ debug "blocking #{aid}"
+ self.synchronize { self[aid].block }
+ end