import Public.Protocols;

int main() {
  object input = Stdio.UDP();
  input->bind(1515);
  input->set_nonblocking(syslog_packet);
  return -1;
}

void syslog_packet(mapping packet) {
  packet += Syslog.decode(packet->data);
  write("%O\n", packet);
}

Output is:
([ /* 8 elements */
  "data": "<86>Oct 12 17:17:01 fido CRON[3720]: pam_unix(cron:session): session closed for user root\n",
  "facility": 10,
  "host": "fido",
  "ip": "127.0.0.1",
  "message": "CRON[3720]: pam_unix(cron:session): session closed for user root\n",
  "port": 33075,
  "severity": 6,
  "timestamp": "Oct 12 17:17:01"
])