What is the data structure behind Clojure's sets?

Question

I recently listened to Rich Hickey\'s interview on Software Engineering Radio. During the interview Rich mentioned that Clojure\'s collections are implemented as trees. I\'m

Answer 1

You probably need to read the work of Phil Bagwell. His research into data structures is the base of Clojure, Haskell and Scala persistent data structures.

There is this talk by Phil at Clojure/Conj: http://www.youtube.com/watch?v=K2NYwP90bNs

There are also some papers:

• Fast Functional Lists, Hash-Lists, Deques and Variable Length Arrays
• Ideal Hash Trees
• More from Phil here

You can also read Purely Functional Data Structures by Chris Okasaki. This blog post talks about the book: http://okasaki.blogspot.com.br/2008/02/ten-years-of-purely-functional-data.html