-/* rset is a "virtual base class", which will never exist on its own */
-/* all instances are rsets of some specific type, like rsisamb, or rsbool */
-/* They keep their own stuff behind the priv pointer. */
+/* rset is a "virtual base class", which will never exist on its own
+ * all instances are rsets of some specific type, like rsisamb, or rsbool
+ * They keep their own stuff behind the priv pointer. */
+
+/* On the old sysno-seqno type isams, the scope was hard-coded to be 2.
+ * This means that we count hits on the sysno level, and when matching an
+ * 'and', we consider it a match if both term occur within the same sysno.
+ * In more complex isams we can specify on what level we wish to do the
+ * matching and counting of hits. For example, we can have book / chapter /
+ * verse, and a seqno. Scope 2 means then "give me all verses that match",
+ * 3 would be chapters, 4 books.
+ * The resolution tells how much of the occurences we need to return. If we
+ * are doing some sort of proximity, we need to get the seqnos of all
+ * occurences, whereas if we are only counting hits, we do not need anything
+ * below the scope. Again 1 is seqnos, 2 sysnos (or verses), 3 books, etc.
+ */