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://

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-uses.html http://sigfpe.blogspot.com/2009/01/haskell-monoids-and-their... Very clear and accessible, IMO.