ISet

protocolsince v0.0-927 clojure.lang/IPersistentSetEdit
implemented for PersistentHashSet PersistentTreeSet

Source docstring:
Protocol for adding set functionality to a collection.
Source code @ clojurescript:src/main/cljs/cljs/core.cljs
(defprotocol ISet
  (^clj -disjoin [coll v]
    "Returns a new collection of coll that does not contain v."))