Add first stab a yacc grammar+lexer

Makefile

@@ -15,7 +15,10 @@ GOFILES=\
 	dnssec.go\
 	keygen.go\
 	string.go\
+	y.go\
 
+y.go:	dns.y
+	goyacc dns.y
 
 include $(GOROOT)/src/Make.pkg
 

dns.y

@@ -6,3 +6,36 @@ package dns
 // A yacc parser for DNS Resource Records contained in strings
 
 %}
+
+%union {
+    string  string
+    rrtype  uint16
+    class   uint16
+    ttl     uint16
+
+}
+
+/*
+ * Types known to package dns
+ */
+%token <rrtype> RR_A RR_NS RR_MX RR_CNAME RR_AAAA RR_DNSKEY RR_RRSIG RR_DS
+
+/*
+ * Other elements of the Resource Records
+ */
+%token <ttl>    TTL
+%token <class>  CLASS
+%token <string> STR
+%%
+rr:     name TTL CLASS 
+  {
+  
+  };
+
+name:   label
+    |   name '.' label
+
+label:  STR
+%%
+
+type DnsLex int