gistfile1.rb

module Commute

  class EnumRouter
    include Enumerable

    # Initialize the router with a main route.
    #
    # main - Enumerable
    def initialize main
      @path = []
      self.route main
    end

    # Push a route on the path (detour).
    #
    # route - Enumerable
    def route route
      @path.push route.to_enum
    end

    # Figure out the next stop.
    def succ
      begin
        return nil if @path.empty?
        @path.last.next
      rescue StopIteration
        @path.pop
        retry
      end
    end

    # Implement Enumerable.
    def each
      yield succ while succ = self.succ
    end
  end
end