You can use these to build persistent data structures. Since you never change anything, you always have all the previous versions of the datastructure available

You can use these to build persistent data structures. Since you never change anything, you always have all the previous versions of the datastructure available. This has applications in file systems (fe zfs,btrfs,...) or databases (CouchDB,....) For an introduction, take a look here: http://blog.incubaid.com/2011/10/03/what-are-you-playing-with-today/ http://blog.incubaid.com/2011/10/03/what-are-you-playing-wit...