@@ -212,6 +212,14 @@ module Streamly.Internal.Data.Fold
212212 -- ** Classifying
213213 -- | In an input stream of key value pairs fold values for different keys
214214 -- in individual output buckets using the given fold.
215+ --
216+ -- Different types of maps can be used with these combinators via the IsMap
217+ -- type class. Hashmap performs better when there are more collisions, trie
218+ -- Map performs better otherwise. Trie has an advantage of sorting the keys
219+ -- at the same time. For example if we want to store a dictionary of words
220+ -- and their meanings then trie Map would be better if we also want to
221+ -- display them in sorted order.
222+
215223 , classify
216224 , classifyWith
217225 , classifyMutWith