+extern type bind_pattern;
+{{Ways of describing in which cases a DNS mapping applies}}
+extern val literal : host -> bind_pattern;
+{{A rule applies only to this particular host.}}
+extern val default : bind_pattern;
+{{A rule applies directly to the domain for the current <tt>vhost</tt> block.}}
+extern val wildcard : bind_pattern;
+{{A rule applies to every host within the current domain.}}
+
+extern val dnsA : bind_pattern -> ip -> dnsRecord;
+extern val dnsAAAA : bind_pattern -> ipv6 -> dnsRecord;