On Jan 20, 7:27 pm, Don Stewart wrote:

http://apfelmus.nfshost.com/monoid-fingertree.html

Thanks Apfelmus for this inspiring contribution!

For additional reading material on a use of Monoids may I suggest my article in the Monad.Reader issue 11 "How to Refold a Map." http://haskell.org/sitewiki/images/6/6a/TMR-Issue11.pdf I also sketched an implementation of my incremental map data structure using Finger Trees. http://haskell.org/haskellwiki/The_Monad.Reader/Discuss_Issue11