What's new in purely functional data structures since Okasaki?New purely functional data structures published since 1998: 2001: Ideal Hash Trees, and its 2000 predecessor, Fast And Space Efficient Trie Searches, by Phil Bagwell: Apparently used as a fundamental building block in Clojure's standard library. 2001: A Simple Implementation Technique for Priority Search Queues, by Ralf Hinze: a really simple and beautiful technique for implementing this important
