- * delimited string, except that " may appear in it, and on output,
- * the char* is a pointer to a string which would be legal either
- * inside or outside " delimiters, and any characters not usually
- * legal in domain names will be quoted as \X (if the character is
- * 33-126 except \ and ") or \DDD.
+ * delimited string, except that " may appear in it unquoted. On
+ * output, the char* is a pointer to a string which would be legal
+ * either inside or outside " delimiters; any character which isn't
+ * legal in a hostname (ie alphanumeric or hyphen) or one of _ / +
+ * (the three other punctuation characters commonly abused in domain
+ * names) will be quoted, as \X if it is a printing ASCII character or
+ * \DDD otherwise.
+ *
+ * (The characters which will be unquoted are the printing 7-bit ASCII
+ * characters except the punctuation characters " ( ) @ ; $ \
+
+ * I.e. unquoted characters are alphanumerics, and the following
+ * punctuation characters: ! # % ^ & * - _ = + [ ] { }