

The best of explanation of Finger Trees (data structure) I have seen - mark_h
http://apfelmus.nfshost.com/monoid-fingertree.html

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brl
Since Finger Trees are powered by Monoids, this is also a very good
explanation of why Monoids are useful in Haskell.

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mark_h
Exactly, and thank you for reminding me -- I meant to add a comment pointing
to this overview of what a monoid is, and why they're useful, from sigfpe:

[http://sigfpe.blogspot.com/2009/01/haskell-monoids-and-
their...](http://sigfpe.blogspot.com/2009/01/haskell-monoids-and-their-
uses.html)

Very clear and accessible, IMO.

