startrule:       network_object(s)
network_object:  /network:(\w+)/ '=' '{'
                     'ip'   '=' ip
                     'mask' '=' ip
                     hosts_or_range(s?)
                 '}'
                 { print "Found network object named $item[1] ", 
                         "with IP $item[6] and MASK $item[9]\n"
                 }

hosts_or_range:  host | host_range
host_range:      /host:\w+/ '=' '{' 'range' '=' ip '-' ip    '}'
host:            /host:\w+/ '=' '{' 'ip'    '=' ip(s) '}'
ip:              / \d{1,3} (?:\.\d{1,3}){3} ;? /x