--- The application currently has two modes. The default, Regex, will
--- compute a regular expression matching the input CIDRs. Reduce, on
--- the other hand, will combine any redundant/adjacent CIDR blocks
--- into one.
-data Mode = Regex | Reduce
+-- | The application currently has six modes. The default, Regex,
+-- will compute a regular expression matching the input
+-- CIDRs.
+--
+-- Reduce, on the other hand, will combine any redundant/adjacent
+-- CIDR blocks into one.
+--
+-- Dupe will show you what would be removed by Reduce.
+--
+-- Diff will show both additions and deletions in a diff-like
+-- format.
+--
+-- List will enumerate the IP addresses contained within the input
+-- CIDRs.
+--
+-- Reverse will perform a reverse DNS (PTR) lookup on each IP
+-- address contained within the input CIDRs.
+--
+data Mode = Regex | Reduce | Dupe | Diff | List | Reverse